DE102024114869A1 - Pneumatic actuator for a metering valve - Google Patents

Abstract

A pneumatic actuator (1) for a metering valve (4) for metering a dosing agent (DS) is described. This pneumatic actuator (1) has a plunger (2) for dispensing the dosing agent (DS) from the metering valve (4). The plunger (2) is formed in one piece and comprises at its end a piston (20) which is mounted in a cylinder (10) of the pneumatic actuator (1) without a seal against the cylinder (10). At least one side (21, 21') of the piston (20) can be pressurized with a pressure medium (DL) to move the plunger (2) in a direction (R). The invention further relates to an actuator module (3) with such a pneumatic actuator (1), a metering head (9) with at least one actuator module (3), a metering valve (4) with a pneumatic actuator (1), and a method for controlling a pneumatic actuator (1).

Description

The invention relates to a pneumatic actuator for a metering valve for dispensing a dosing agent, which pneumatic actuator has a plunger for dispensing the dosing agent from the metering valve, and to an actuator module with such a pneumatic actuator. The invention further relates to a metering head with at least one actuator module, a metering valve with a pneumatic actuator, and a method for controlling a pneumatic actuator for a metering valve for dispensing a dosing agent.

Metering valves are used in a wide variety of applications to precisely dispense a medium, typically a liquid to viscous dosing agent. In so-called "micro-dosing technology," it is often necessary to apply very small quantities of the medium to a target surface with high precision—that is, at the right time, in the right place, and in a precisely measured amount. The dispensing of the dosing agent from a metering valve can be contact-based or non-contact, meaning without direct contact between the metering valve and the target surface. The dosing agent can be applied to the target surface, for example, in a diffuse, linear, and/or spot manner.

Metering valves are increasingly used in the manufacture of rotors and stators for motors and generators. Such rotors and stators typically consist of several thin sheets, which are, for example, stamped from a continuous strip or cut using a laser, with the individual sheet metal parts then being joined into stacks. In addition to mechanical joining methods for producing these sheet metal stacks, adhesive bonding processes are used, for example, to achieve the highest possible efficiency of the rotors and stators.

In some processes, adhesives, such as cyanoacrylate adhesives, are applied to sheet metal parts at defined points, and these parts are then bonded together to form sheet metal stacks. Applying the adhesive in a specific pattern, for example, in the form of individual adhesive dots, can be achieved using appropriate metering valves. This reduces material usage compared to so-called baking varnish technology, and curing can occur without heating, making production more cost-effective.

Due to increasing electrification, ever higher demands are being placed on the efficiency of rotors and stators, while cost pressures are simultaneously growing. Furthermore, the mechanical requirements for rotors and stators, as well as for the joining process of the laminated cores, are constantly increasing. For example, there is a desire to increase the rotational speed of electric motors and generators and to boost the power output of electric motors. Therefore, efforts are being made to apply individual dots of adhesive to the sheet metal parts for bonding and to achieve the highest possible density of adhesive dots.

In other areas of technology, it is also desirable to apply dosing materials in the form of individual dots to a target surface in such a way as to achieve the highest possible density of individual dots or a high dot density. This applies, for example, to the additive manufacturing of objects or painting applications.

To generate a specific dispensing pattern, several dispensing valves are often used in parallel to apply the same dispensing surface with the metering material. In such multiple dispensing systems, the dispensing valves can be arranged on a dispensing head and move together with it. While such a dispensing head with several dispensing valves, for example, fixed to it, can achieve a certain point density and can have a relatively simple design, the maximum possible point density in known systems is limited because the installation space of the individual dispensing valves often does not permit an even denser arrangement, for example, on a single dispensing head. Therefore, known systems with dispensing valves often can no longer meet the increasing demands placed on the dispensing process in various technical fields.

It is an object of the present invention to provide a pneumatic actuator for a metering valve for dispensing a dosing substance, an actuator module with a pneumatic actuator, a metering head with at least one actuator module, a metering valve with a pneumatic actuator and a method for controlling a pneumatic actuator for a metering valve for dispensing a dosing substance, with which the aforementioned disadvantages are reduced and preferably avoided.

This problem is solved by a pneumatic actuator according to claim 1, an actuator module according to claim 10, a metering head according to claim 14, a metering valve according to claim 17 and a method according to claim 18.

A pneumatic actuator according to the invention is designed for use in a metering valve for dispensing a dosing agent. In particular, the pneumatic actuator is configured to enable the intended dispensing of the dosing agent by a metering valve. The metering valve can preferably The pneumatic actuator may be a jet valve. It has at least one plunger for dispensing metering fluid from the metering valve, provided the pneumatic actuator is part of a metering valve. The plunger is also referred to as the ejection element. According to the invention, the plunger is formed in one piece. This means that the plunger is manufactured from only one continuous piece and/or consists of a single part.

According to the invention, the plunger comprises at least one piston at its end, which is movably mounted in a cylinder of the pneumatic actuator without a seal relative to the cylinder, in particular relative to an inner wall of the cylinder facing the piston. The piston is preferably movably mounted in a cylindrical interior of the pneumatic actuator. The cylinder is, in particular, a hollow cylinder. Accordingly, the piston can be movably arranged in a hollow cylinder of the pneumatic actuator and mounted without a seal relative to an inner wall of the hollow cylinder. The term "seal-free" means that there is no seal between an outer surface of the piston and an associated inner wall of the cylinder or hollow cylinder. In particular, the piston is designed without a piston seal along its entire longitudinal extent. The plunger is arranged at least partially in the cylinder or hollow cylinder, with parts of the plunger, in particular a plunger tip, projecting out of the cylinder. The cylinder or hollow cylinder is preferably arranged within a housing of the pneumatic actuator.

The plunger comprises an elongated pushrod that connects to the piston on one side and is integrally formed with the piston. The pushrod has a plunger tip at its free end, opposite the piston, measured along its longitudinal axis. The pushrod can be movably mounted, at least partially, within the cylinder or hollow cylinder of the pneumatic actuator, particularly without a seal against an associated inner wall of the cylinder. The pushrod's function is to dispense metering fluid from a metering valve via the plunger tip, with the piston forming a plunger head, thereby enabling movement of the entire plunger.

The pneumatic actuator is designed such that at least one side or surface of the piston, in particular a piston base and/or a piston top, can be pressurized, directly and/or indirectly, with a pressure medium to move the plunger in one direction. Preferably, at least one side of the piston can be directly pressurized with a pressure medium during operation of the pneumatic actuator to set the plunger in motion. The piston can also be referred to as a pneumatic piston. Preferably, a controllable pneumatic valve, in particular a 5/2-way valve, is associated with the pneumatic actuator to pressurize the piston with a pressure medium during operation.

The pneumatic actuator preferably comprises at least one actuator chamber. During operation, the actuator chamber can be filled with a pressure medium, with one side of the piston being pressurized to move the plunger. The actuator chamber is formed within the housing of the pneumatic actuator and is bounded by one side or surface of the piston. In particular, the actuator chamber can encompass a portion of the interior of the cylinder or hollow cylinder in which the piston is movable.

Advantageously, a one-piece plunger allows for a minimal moving mass. Unlike conventional plungers, no connecting elements are required to join individual plunger components. In multi-piece plungers, a pushrod is often screwed or otherwise connected to a piston, increasing the mass. The one-piece design results in a plunger mass lower than that of conventional multi-piece plungers. Furthermore, the one-piece construction contributes to the relatively inexpensive manufacturing and less wear-prone nature of the plunger compared to multi-piece designs, thereby reducing the manufacturing and operating costs of the pneumatic actuator.

Advantageously, due to the relatively low mass of the plunger, the actuator chamber of the pneumatic actuator, which is filled with pressurized medium to deflect the plunger, can have a relatively small filling volume, especially compared to known pneumatic actuators. This allows a specific pressure to be generated in the actuator chamber very quickly, achieving the highest possible plunger acceleration. This also allows for the highest possible plunger velocity during operation. Furthermore, the comparatively small filling volume of the actuator chamber allows the installation space of the pneumatic actuator to be as small and compact as possible, especially smaller than in known pneumatic actuators. This space saving can be particularly advantageous in multi-dose applications and/or in dosing heads with multiple dosing valves. This allows for an increased point density compared to known systems.

Furthermore, the one-piece construction and the relatively small (piston) can be advantageous. This allows for the use of a relatively small piston, for example, a reduced piston diameter compared to conventional pneumatic actuators. This enables the plunger to be mounted in the cylinder or hollow cylinder without a seal, while still maintaining acceptable pressure medium consumption during operation. The term "seal-free" means that a free space can exist between the outer surface of the piston and the inner wall of the cylinder or hollow cylinder. Specifically, during plunger movement within the pneumatic actuator, there is no direct contact between the piston and the inner wall forming the cylinder or hollow cylinder. Eliminating a (piston) seal between the piston and the cylinder or hollow cylinder can reduce wear on the pneumatic actuator and minimize friction during operation, which has a beneficial effect on the plunger's speed and/or acceleration.

The special pneumatic actuator can be part of an actuator module, a metering head, and/or a metering valve. This is described elsewhere. Since the piston can move up and down in a cylindrical (hollow) space within the pneumatic actuator, the cylinder of the pneumatic actuator, in which the piston is mounted without seals and is movably mounted, is preferably a hollow cylinder. The invention is described, without limitation and unless explicitly stated otherwise, using a cylinder in the form of a hollow cylinder.

The invention relates to a pneumatic actuator for a metering valve for dispensing a metering substance, in particular a pneumatic actuator as described above, which pneumatic actuator has a plunger for dispensing metering substance from the metering valve. The plunger comprises at its end a piston which is movably mounted in a cylinder or in a hollow cylinder of the pneumatic actuator. At least one side of the piston can be pressurized with a pressure medium to move the plunger in one direction. The pneumatic actuator is preferably designed such that two opposite sides of the piston can be pressurized with a pressure medium, preferably directly, to move the plunger in different, opposite directions. Accordingly, the pneumatic actuator can comprise two actuator chambers, with the two sides of the piston facing different actuator chambers. At least one pneumatic roller valve or rotary valve is associated with the pneumatic actuator to supply it with pressure medium. Preferably, the pneumatic actuator can have a roller valve in the form of a 5/2-way valve, as described elsewhere.

An actuator module according to the invention comprises a pneumatic actuator according to the invention. Accordingly, the actuator module has at least one plunger with an end piston and a cylinder or hollow cylinder in which the plunger is slidably and without seals mounted. Preferably, the actuator module has at least one actuator chamber, and in particular two actuator chambers.

In addition to the pneumatic actuator, the actuator module includes a fluidic unit connected to the pneumatic actuator. This connection can be fixed or reversible/detachable. Preferably, at least parts of the fluidic unit can be connected to the cylinder or hollow cylinder of the pneumatic actuator, which contains the piston, and form a module. The actuator module can preferably be reversibly connected to a module carrier, to which at least one pneumatic valve and a media supply are assigned, including a metering valve. This will be described later.

The fluidic unit is designed to supply a metering medium in the area of the plunger tip, at least during operation. The actuator module can comprise a complete or a partial fluidic unit. Consequently, it is possible for the actuator module to contain only parts of a fluidic unit that can interact with other components to form a fully functional fluidic unit.

Advantageously, the modular design allows for particularly quick and easy disassembly of the wear parts of a metering valve, for example, for cleaning, maintenance, and/or replacement. These wear parts include the plunger, a nozzle of the fluidic unit, and a seal between the fluidic unit and the plunger. Furthermore, it is advantageous to keep tolerance chains within the actuator module as tight as possible. This optimizes concentricity between the plunger tip and the nozzle, especially the nozzle opening. Another advantage is the use of turned parts in the actuator module, minimizing the number of parts requiring the highest manufacturing precision. This reduces the manufacturing costs of the actuator module. Additionally, optimized material pairings can be used on the plunger's running surfaces within a single module to further reduce wear. Consequently, the running surfaces of the piston and/or the pushrod and the respective associated areas of the inner wall of the hollow cylinder and/or the pneumatic actuator, with respect to which a relative movement takes place, can have materials matched to each other.

A dosing head according to the invention comprises at least one actuator module according to the invention, wherein the actuator module is in particular detachably arranged on the dosing head and wherein the dosing head has a supply element with channels to supply the actuator module with dosing material and pressure medium during operation.

Alternatively or additionally, the dosing head has a plurality of actuator modules according to the invention, i.e., two or more actuator modules, wherein the respective actuator modules are in particular detachably arranged on the dosing head and wherein the dosing head has a supply element with channels to supply the respective actuator modules separately or independently of each other with dosing material and pressure medium.

Regardless of the specific design, some or all channels can be integrated into the supply element. The dispensing head can have a holder for each actuator module to secure the actuator module to the dispensing head during operation. The respective holder can preferably be provided by the supply element. In addition to the supply element, the dispensing head can have further elements, such as a movement mechanism to move the dispensing head and the actuator modules arranged on it relative to a dispensing surface. Preferably, the dispensing head can have a reservoir for the pressure medium. All pneumatic valves of the dispensing head can be supplied from this reservoir or tank during operation. Advantageously, this reservoir can act as a buffer in the event of a temporarily high demand for pressure medium, for example, during pulsed, simultaneous dispensing of the metering medium by a large number of actuator modules. Furthermore, the design of the dispensing head can be simplified because a separate supply for each pneumatic valve is no longer necessary.

The metering head can additionally have at least one pneumatic valve to supply the respective actuator modules with a pressure medium during operation, in particular via the channels in the supply element. The respective pneumatic valve can be part of the supply element, and in particular can be detachably arranged on it. Furthermore, the metering head preferably includes a media supply to supply the respective actuator modules with metering fluid during operation, in particular via the channels in the supply element. The channels of the supply element can be part of the media supply. Preferably, the supply element can be connected to a metering fluid reservoir, which is preferably designed separately from the metering head, in order to supply the metering fluid to the supply element.

Preferably, the dispensing head has at least one module carrier to which a pneumatic valve and a media supply are assigned. The dispensing head can have multiple such module carriers, with each actuator module being detachably coupled to a module carrier to form a dispensing valve. The respective module carrier is preferably also designed to hold the actuator module on the dispensing head during operation. Depending on the embodiment, some or all of the dispensing head's module carriers can be implemented using the supply element. The dispensing head can be movable during operation. For example, the (entire) dispensing head with the respective actuator module can be rotated during operation and/or moved linearly, particularly with respect to a dispensing surface.

A metering valve according to the invention comprises a pneumatic actuator according to the invention, preferably an actuator module according to the invention, and at least one controllable pneumatic valve and a media supply. It is also possible for a metering valve to comprise a pneumatic actuator according to the invention and a fluid unit, which can be detachably coupled to it, as well as a controllable pneumatic valve and a media supply. This embodiment therefore does not have an actuator module. Regardless of the specific design, the pneumatic valve can preferably be a 5/2-way valve. Optionally, the valve can be a pneumatic roller valve, e.g., a 5/2-way valve. Regardless of the specific design, the metering valve can be part of a metering head. However, the metering valve can also be operated independently, in particular independently of a metering head.

A method according to the invention relates to the control of the operation of a pneumatic actuator for a metering valve, in particular as part of a metering valve, for metering a dosing agent, preferably a pneumatic actuator according to the invention. The pneumatic actuator has a plunger for dispensing dosing agent from the metering valve, wherein the plunger is formed in one piece and comprises at its end a piston which is mounted in a cylinder or hollow cylinder of the pneumatic actuator without a seal against the cylinder or hollow cylinder, in particular the inner wall of the cylinder. In the method, at least one side or surface of the piston is acted upon with a pressure medium, in particular directly, in order to move the plunger in one direction.

The method preferably controls the operation of a pneumatic actuator of an actuator module, wherein the actuator module can be part of a dosing head. If the dosing head has a plurality of actuator modules, the pneumatic actuators can preferably be controlled separately or independently of each other. Furthermore, in The process controls the operation of a pneumatic actuator of a metering valve. The metering valve can be part of a metering head or can be operated independently of a metering head.

Advantageously, the actuator module, the dosing head and the dosing valve as well as the method for controlling the pneumatic actuator are based on the pneumatic actuator according to the invention, so that the same advantageous effects can be achieved in each case.

Further, particularly advantageous embodiments and developments of the invention are described in the dependent claims and the following description, wherein the claims of one claim category may also be further developed analogously to the claims and descriptions of another claim category, and in particular, individual features of different embodiments or variants may be combined to form new embodiments or variants. Some advantageous developments of the pneumatic actuator are described with reference to features of a metering valve, an actuator module, or a metering head. With regard to these features, it is assumed that the pneumatic actuator is part of the corresponding component and/or at least interacts with it, so that the described effects are achieved.

The pneumatic actuator is preferably arranged in a housing that has at least a partially cylindrical outer shape. Additionally, the housing may have non-cylindrical areas, both inside and out. For example, the housing may have external locking mechanisms to hold it to a metering head and/or seals to connect the pneumatic actuator to compressed air channels. In addition to the hollow cylinder and the plunger, further elements of the pneumatic actuator may be arranged in the housing, in particular two actuator chambers, a (stroke) stop for the plunger, and optionally a diaphragm. The housing is preferably made of metal. The housing can preferably be connected to a cylindrical part of the fluidic unit by nesting them together to form an actuator module.

The pneumatic actuator is preferably designed such that two opposing sides or surfaces of the piston can be pressurized, preferably directly, with a pressure medium to move the plunger in different, opposite directions. Accordingly, the pneumatic actuator can comprise two actuator chambers, with the two sides of the piston facing different actuator chambers. The two actuator chambers are preferably arranged in the housing of the pneumatic actuator. Each actuator chamber can comprise at least a portion of the hollow cylinder in which the piston moves during operation. The volume of each actuator chamber can preferably correspond to the piston's stroke volume during operation.

Preferably, a first side of the piston, e.g., the piston base, can face a first actuator chamber, in particular defining the actuator chamber in one direction. A second side of the piston, opposite the first side, can face a second actuator chamber, in particular defining the actuator chamber in one direction. This means that the two actuator chambers are separated by the movable piston. The two actuator chambers are preferably formed by an inner wall of the hollow cylinder and by an outer surface of the piston, optionally by an outer surface of the pushrod.

The volume of the two actuator chambers can change depending on the piston's position within the hollow cylinder. For example, a first actuator chamber, completely filled with pressurized fluid, may briefly have a maximum volume, while the second, other actuator chamber simultaneously has a minimum volume. Each actuator chamber includes at least one supply line for pressurized fluid to pressurize the side of the piston facing that chamber. This supply line can be implemented, for example, via bores in the pneumatic actuator housing. The second actuator chamber, in particular, can have multiple bores or openings in the housing, arranged, for example, in a circular pattern, branching off from an annular compressed air channel. The respective actuator chamber with its supply line is also referred to as the actuator space.

The two actuator chambers each have their own connection for a pressure medium to fill the respective actuator chamber with pressure medium and/or to discharge pressure medium from the actuator chamber. Preferably, the respective connection is connected to a working port of a pneumatic valve. The pressure medium can preferably be compressed air, e.g., compressed room air. In principle, other compressed gases are also possible. The invention is described, without limitation, using compressed air as the pressure medium. The pressure of the inflowing pressure medium and/or the pressure of the pressure medium in the respective actuator chamber for deflecting the plunger can be at least 2 bar, preferably at least 4 bar, preferably at least 6 bar and/or at most 100 bar, preferably at most 20 bar, preferably at most 10 bar. The piston, and thus the entire plunger, can be moved up and down in the hollow cylinder of the pneumatic actuator by means of the pressure medium.

Advantageously, the plunger can be moved particularly efficiently in different directions by means of two actuator chambers, with the actuator chambers being filled and vented accordingly by means of the pneumatic valve. The description assumes, without limitation, that the pneumatic valve is a 5/2-way solenoid valve. Preferably, following the filling of the first actuator chamber, the plunger is moved towards the nozzle of the fluid unit, in particular such that the plunger tip directly contacts a nozzle insert. In a jet valve, this movement of the plunger is referred to as an ejection movement because the movement of the plunger tip actively ejects a droplet of the metering medium from the nozzle. The invention is described, without limitation, using a jet valve as an example. To move the plunger away from the nozzle, the second actuator chamber can be filled with pressurized medium and/or the first actuator chamber can be vented to reduce pressure. Preferably, both processes can occur in parallel, at least temporarily. Accordingly, in this process it is preferred that the first actuator chamber is filled while the second actuator chamber is vented at the same time, and vice versa.

The movement of the plunger in the pneumatic actuator preferably occurs parallel to the dispensing direction of the metering material from the metering valve. To control the pneumatic actuator, particularly to build up or release pressure in the respective actuator chamber, the pneumatic valve can be controlled accordingly by a control unit. The control unit can be part of the individual metering valve and/or a higher-level control unit can be provided that preferably controls the operation of several metering valves and/or several metering heads separately.

Advantageously, this pneumatic actuator eliminates the need for a spring to move the piston, which improves its performance. In known systems, a spring is often used to move the plunger towards the nozzle for a closing motion, but the spring force must be overcome for a return movement. To overcome this spring force, pistons with relatively large diameters are frequently used, particularly larger than those in the described pneumatic actuator. This results in an increase in the overall mass of the piston and plunger, which negatively impacts acceleration and plunger velocity. A large piston diameter can also necessitate a larger actuator chamber volume, which can further reduce the pneumatic actuator's performance. Additionally, the large piston diameter can increase the plunger mass, potentially leading to high wear at the plunger tip due to contact with the nozzle. Furthermore, a large piston diameter requires more space, thus increasing the overall installation volume of the pneumatic actuator. The aforementioned disadvantages can be significantly reduced by the special pneumatic actuator, particularly due to its one-piece construction and the two actuator chambers. For the sake of completeness, it should be noted that the pneumatic actuator can, in principle, also have only one actuator chamber, in which case a counter-rotating movement of the plunger can be effected by means of spring force. However, it is preferred that the pneumatic actuator comprises two actuator chambers, and the invention is described with reference to such an embodiment.

Since the piston is mounted without a seal in the hollow cylinder, a fluid connection between the two actuator chambers can exist, at least temporarily, during operation. Preferably, the gap between an outer surface of the piston, also referred to as the plunger head, and an inner wall of the hollow cylinder can be less than 5 µm. To minimize the consumption of pressurized fluid during operation, the pneumatic actuator can have at least one sealing element. For this purpose, the pneumatic actuator can have a (stroke) stop for the piston, which stop forms a first sealing element for the piston. The (stroke) stop is preferably arranged in the housing of the pneumatic actuator, e.g., it can be removable. For example, the (stroke) stop can be inserted or pressed into the cylindrical housing of the pneumatic actuator from above. The (stroke) stop is preferably oriented towards a side of the piston that points away from the plunger tip.

The first sealing element is preferably made of the same material as the (stroke) stop itself. The first sealing element is preferably designed to form a tight seal between the piston and an inward-facing wall of the cylinder or hollow cylinder in a first end position of the plunger. In this description, the term "tight" is preferably understood to mean a substantially airtight seal. The first end position of the plunger is preferably defined by the piston being in contact with the (stroke) stop of the pneumatic actuator and/or by the volume of the first actuator chamber being at its minimum. Accordingly, the nozzle opening can be unobstructed in the first end position of the plunger.

The first sealing element preferably interacts with a (base) surface of the piston such that, in the first end position of the plunger, the first actuator chamber is tightly, and in particular essentially airtight, sealed against the second actuator chamber. The first sealing element is preferably part of the first actuator chamber. The respective (base) surface of the piston is understood to be a portion of the piston that is essentially orthogonal to a direction of movement of the piston during operation.

In the case of a piston with a cross-sectionally concentric shape, the (stroke) stop can comprise at least one section that points towards the piston and is designed as a hollow cylinder. The hollow cylinder of the (stroke) stop can extend into the hollow cylinder of the pneumatic actuator. Preferably, the piston can directly contact the hollow cylinder of the (stroke) stop in its end position. In particular, tight contact can be established between a (base) surface of the piston and an adjacent part of the hollow cylinder, provided that the hollow cylinder is directly contacted by the piston or by a (base) surface of the piston and/or when the piston is in the first end position.

The (stroke) stop is preferably designed to introduce compressed air into the first actuator chamber and/or to discharge compressed air from the first actuator chamber. For this purpose, the hollow cylinder of the (stroke) stop can be filled with compressed air, serving as the compressed air supply line. The hollow cylinder of the (stroke) stop can be part of the first actuator chamber. The material of the first sealing element and/or the (stroke) stop is preferably selected to be metal. Since there is no double fit between the first sealing element and the plunger in the nozzle, no tolerances need to be compensated for, and a sealing effect is achieved even with hard materials.

The pneumatic actuator can have an elastic, in particular reversibly deformable, sealing element designed to form a tight seal between the piston and an inner wall of the cylinder or hollow cylinder in a second end position of the plunger, which differs from the first end position. This second sealing element is preferably separate from the first sealing element. The second end position of the plunger is preferably defined by the volume of the second actuator chamber being minimal and/or by the plunger tip directly contacting the nozzle, in particular a nozzle insert. The metering valve is then temporarily closed. Accordingly, the pneumatic actuator can have an elastic end-position seal for the plunger.

The second sealing element preferably interacts with a (base) surface of the piston in such a way that, in the second end position of the plunger, the second actuator chamber is tightly, and in particular essentially airtight, sealed from the first actuator chamber. The second sealing element is preferably part of the second actuator chamber. The second sealing element preferably comprises or is itself an elastomer. Preferably, the sealing element comprises a lip that points towards the (base) surface of the piston and directly contacts it in the second end position of the plunger. The sealing element can also be implemented as an O-ring, e.g., as an elastomer, or as a bellows, e.g., made of metal.

Regardless of the material, the (first and/or second) sealing element is preferably adapted to the design of the piston, in particular to the shape of the (base) surface and/or to a cross-sectional area of the piston. Accordingly, the respective sealing element can also be oval or rectangular. Consequently, the piston itself can have a polygonal or oval cross-section. This means that the invention is not limited to round pistons (cross-sections). Consequently, the hollow cylinder in which the piston is movable can also have a polygonal or oval cross-section and need not necessarily be round. However, it is preferred that the hollow cylinder, the piston, and the pushrod are each circular in cross-section.

Advantageously, the sealing elements allow for a further reduction in compressed air consumption during operation, thus lowering operating costs. When the metering valve is closed, which is the predominant operating state for jet valves, the pneumatic actuator's air consumption can be significantly reduced, with no compressed air being consumed at all during this time. Furthermore, the elasticity of the second sealing element ensures that the plunger is not decelerated before impacting the nozzle insert, thus maintaining the desired metering parameters.

The pneumatic actuator can, alternatively or additionally to the described sealing elements, have a (sealing) diaphragm that rests on the piston, particularly on a side of the piston facing away from the plunger tip. Preferably, the pneumatic actuator can have a combination of a first sealing element and a diaphragm (instead of a second sealing element). Preferably, one side of the diaphragm faces the piston and the opposite side faces away from the piston. The diaphragm is preferably separate from the plunger. This means that the diaphragm is then not rigidly or permanently attached to the piston. The diaphragm is connected to the piston. In this case, there is no positive fit or material bond between the diaphragm and the piston. Alternatively, the diaphragm can be connected to the piston, preferably only at a central point of the diaphragm. The invention is described, without limitation, using a loose diaphragm as an example.

The diaphragm is movably mounted within the cylinder or hollow cylinder and can be moved into different positions. Preferably, the diaphragm can be pressurized and/or deflected by means of a pressure medium. Preferably, one side of the diaphragm can be directly pressurized to move the diaphragm and/or the piston in one direction, particularly for an ejection movement. Preferably, a counter-movement, contrary to the ejection movement, of the diaphragm and/or the piston can be achieved by directly pressurizing a side of the piston facing away from the diaphragm, whereby the diaphragm is moved (indirectly) by means of the plunger. Accordingly, the diaphragm is preferably moved up and down within the hollow cylinder together with the piston.

The diaphragm is preferably movably mounted within the cylinder or hollow cylinder such that, in a sealing position, the diaphragm forms a tight connection, particularly a substantially airtight connection, to an inner wall of the cylinder or hollow cylinder. In another position, the diaphragm is positioned within the cylinder or hollow cylinder such that the pressure medium can flow from one side of the diaphragm to the opposite side. This means that the diaphragm only provides a seal in the sealing position and, in other positions and/or during movement of the diaphragm, can be passed (laterally) by the pressure medium. If the diaphragm is not in the sealing position, the pressure medium can flow between the diaphragm and the inner wall of the hollow cylinder. Consequently, it is preferred that the diameter of the diaphragm be larger than the diameter of the piston and/or smaller than the inner cross-section of the hollow cylinder of the pneumatic actuator, apart from a stop for the diaphragm to create a seal.

The hollow cylinder preferably includes an internal stop for the diaphragm to position the diaphragm in the sealing position. The stop can preferably be implemented by a section-by-section change in the internal cross-section of the hollow cylinder. Preferably, the stop is in the form of a step connecting two sections of the hollow cylinder with different diameters. Consequently, the diaphragm can contact the stop directly in sections, particularly resting on top of it, e.g., on the step, with the diaphragm in the sealing position. To move the diaphragm into the sealing position, it can be pressurized with a pressure medium, e.g., starting from the first end position of the plunger, so that the diaphragm moves together with the plunger. The piston is then only indirectly pressurized with the pressure medium. As a result of the movement, an outer part of the diaphragm rests against the stop, creating a sealing effect. A central section of the diaphragm is further deflected or bent by the one-sided overpressure, so that the plunger is pressed into the nozzle insert by means of the diaphragm. Advantageously, this ensures that no air is consumed by the pneumatic actuator when the metering valve is closed. The diaphragm can therefore form a partition between the two actuator chambers of the pneumatic actuator, particularly in the sealing position.

To open the metering valve or to move the plunger to its first end position, the plunger can be directly pressurized with compressed air on the side facing away from the diaphragm. The plunger moves together with the diaphragm until it reaches its first end position and/or until the diaphragm contacts a (stroke) stop of the pneumatic actuator. As described, the (stroke) stop can comprise a hollow cylinder pointing towards the piston, with one wall of the hollow cylinder being contactable by the diaphragm. This wall of the (stroke) stop can have one or more (material) recesses or cutouts facing the piston, with no direct contact between the diaphragm and the hollow cylinder or (stroke) stop occurring in the area of the recesses. Advantageously, this allows compressed air from the first actuator chamber to enter the interior of the hollow cylinder of the (stroke) stop through the recesses during piston movement towards the (stroke) stop, i.e., during an upward movement, and to be discharged from the pneumatic actuator via this opening. This minimizes or eliminates any resistance to the piston's (upward) movement. Furthermore, this advantageously ensures that the plunger (via the diaphragm) is securely pressed against the (stroke) stop, and not just that the diaphragm rests against it and seals. Accordingly, in this embodiment, the (stroke) stop itself preferably does not have an additional sealing element. The pneumatic actuator is preferably designed such that, at least in the first end position of the plunger, and preferably also during an (upward) movement of the piston, a constant airflow can pass through the diaphragm towards the (stroke) stop, preferably laterally between the diaphragm and the piston. ran and the inner wall of the hollow cylinder of the pneumatic actuator.

The stop for the diaphragm is preferably designed such that the diaphragm contacts the stop before the plunger tip contacts the nozzle insert. Preferably, the stop is designed such that the plunger is moved by a distance of at most 100 µm after the diaphragm is in the sealing position. This means that the diaphragm is deflected or bent by at most 100 µm in a central region after reaching the sealing position. Advantageously, this results in the plunger being hardly or not at all damped before impacting the nozzle insert, while still optimizing air consumption.

The diaphragm is preferably very thin to achieve the lowest possible spring rate. For example, the diaphragm can be disc-shaped, and in particular, free of cavities. The thickness of the diaphragm can be, for example, at least 5 µm, preferably at least 10 µm and/or at most 100 µm, preferably at most 50 µm. The diaphragm material can be metal and/or plastic and/or elastomer. For example, the diaphragm can be made of stainless steel. The diaphragm is preferably round. In principle, oval or rectangular diaphragms are also possible.

The sealing membrane described above and/or the features described in connection with the sealing membrane can preferably be used in the pneumatic actuator according to the invention. However, it should be noted that a sealing membrane and/or the features described in connection with the sealing membrane are not limited to a pneumatic actuator according to the invention. Rather, the use of a sealing membrane as an end-position seal in a pneumatic actuator constitutes an independent aspect of the invention. Accordingly, a sealing membrane as an end-position seal, and in particular the described embodiments, can be used in combination with various pneumatic actuators, e.g., with known pneumatic actuators. It is therefore particularly possible for a sealing membrane to be used as an end-position seal for operating a pneumatic actuator that has a multi-part plunger and/or a piston with a piston seal.

The pneumatic actuator is preferably designed such that the weight of the entire plunger is less than 2 grams, preferably less than 1.5 grams, more preferably less than 1 gram, and particularly preferably less than 0.5 grams. Alternatively or additionally, the plunger may weigh at least 0.1 grams, preferably more than 0.1 grams. Preferably, the plunger may weigh at least 0.25 grams and/or at most 1.4 grams.

The plunger material can be selected from hard metal, e.g., tungsten carbide, preferably with a density of 14.5 g/ ^cm³ , and/or from ceramic, e.g., zirconium oxide, preferably with a density of 6 g/ ^cm³ , and/or silicon nitride, preferably with a density of 3.21 g/ ^cm³ . Alternatively or additionally, the plunger material can be selected from polyetheretherketone (PEEK), preferably with a density of 1.32 g/ ^cm³ , and/or from polyetheretherketone with carbon fibers, preferably with a density of 1.42 g/ ^cm³ , and/or from titanium, preferably with a density of 4.51 g/ ^cm³ , and/or from carbon fiber reinforced plastic, preferably with a density of 1.5 g/ ^cm³ . The plunger material can be a mixture of some or all of the aforementioned materials. Particularly preferred are very lightweight materials for the plunger, e.g., silicon nitride and PEEK with carbon fibers and CFRP. For example, the plunger can comprise, or even consist entirely of, PEEK with a carbon fiber content of 30 wt.%. In principle, the plunger material, e.g., a thermoplastic, can have a carbon fiber content of up to 50 wt.% or up to 60 wt.%.

The outer diameter of the piston can be less than 6 millimeters (mm), preferably less than 5 mm. Alternatively or additionally, the outer diameter of the piston can be more than 3 mm, preferably more than 4 mm, in particular about 4.62 mm.

As a purely illustrative example, a piston can have a diameter of approximately 4.62 mm, with the entire plunger (including the piston) consisting of approximately 1.16 grams of hard metal, 0.49 grams of zirconium oxide, and 0.26 grams of silicon nitride. This advantageously allows for a particularly light and compact plunger, whereas conventional plungers and pistons for pneumatic actuators typically weigh more than 5 grams, often between 5 and 20 grams, and have a piston diameter often between 15 and 30 millimeters. An advantage of the relatively low mass is reduced wear when the plunger impacts the nozzle, especially with filled media or metering fluids. With filled metering fluids containing particularly soft components, such as solder paste or gold filling, the particles are not deformed as much by the special plunger as with heavier or conventional plungers, which can lead to nozzle clogging. Therefore, the nozzle requires less frequent cleaning due to the special plunger, resulting in a more stable metering process. This can be achieved. Furthermore, the described plunger allows for a particularly small installation space for the pneumatic actuator. By setting a specific plunger stroke length during operation, e.g., 500 µm, comparable plunger closing speeds can be achieved even with a relatively small piston diameter, as with known pneumatic actuators with considerably heavier plungers. The low weight of the plunger and the provision of two actuator chambers can enhance this effect. With larger plunger strokes, e.g., greater than 500 µm, significantly higher plunger speeds than with known pneumatic actuators can be achieved with this special pneumatic actuator.

Preferably, the plunger speed and/or acceleration can be adjusted during operation by at least one of the following parameters: the (filling) pressure of the actuator chambers, the mass of the plunger, or the stroke of the plunger. In principle, the pneumatic actuator can be designed such that a theoretical acceleration (without friction or losses) is greater than 1000 g.

Preferably, the pneumatic actuator is designed such that only a specific section of the plunger is wetted with the metering medium during operation. Preferably, a wetted section of the plunger rod, extending from the plunger tip, can have a length of at most 6 mm, more preferably at most 5 mm, more preferably at most 4 mm, more preferably at most 3 mm, most preferably at most 2 mm, and particularly preferably at most 1 mm. Advantageously, minimizing the wetted section of the plunger rod can help to reduce damping and friction occurring at the plunger during operation.

The pneumatic actuator can have at least one seal designed such that only a specific section of the plunger comes into contact with the metering fluid. This seal, also referred to as a metering fluid seal, can have a projection with a sealing lip facing and/or protruding towards the plunger tip. This allows a sealing effect to be created closer to the plunger tip, thereby shortening the wetted length of the plunger. Preferably, such a metering fluid seal can be implemented as part of the fluidic unit, particularly in a cylindrical section of the fluidic unit.

The pneumatic actuator can be designed such that the pushrod, at least in the area of the metering seal of the pneumatic actuator, has a coating that reduces the coefficient of friction of the pushrod's base material. Coefficient of friction refers to the frictional force, i.e., the value of the friction acting between the pushrod and the metering seal.

The pneumatic actuator can be designed such that the ratio of the piston's outer circumference to the pushrod's outer circumference is at least 3:1 or greater, preferably 4:1. For example, the diameter of a round piston can be approximately 4 mm and the diameter of a round pushrod approximately 1 mm. The pushrod diameter can preferably be a mean diameter based on the pushrod's longitudinal extent. Advantageously, using the smallest possible pushrod diameter further reduces friction in the area of the metering fluid seal.

As described, the pneumatic actuator can have a (stroke) stop for the piston to set a specific plunger stroke or actuator stroke and/or a specific plunger speed during operation. The (stroke) stop is preferably designed to move the plunger into the first end position and/or to hold the plunger in the first end position. In particular, the (stroke) stop can terminate the plunger movement as soon as the first end position is reached. Preferably, the (stroke) stop comprises a hollow cylinder, wherein the piston, in the first end position, bears (directly or indirectly) against an annular wall of the hollow cylinder facing the piston. The (stroke) stop can be fixedly connected to the housing of the pneumatic actuator or can be detachably integrated into the housing. Preferably, the (stroke) stop can be pressed into a cylindrical section of the housing of the pneumatic actuator, in particular sealed against the housing.

To set a specific actuator stroke, the position of the (stroke) stop in the pneumatic actuator can be changed, and/or the position of the (stroke) stop relative to the pneumatic actuator housing can be set, and/or the length of the (stroke) stop can be set. For example, one or more washers can be placed on the (stroke) stop to achieve a specific distance between the (stroke) stop and the nozzle. It is also possible for the (stroke) stop to be adjustable, e.g., automatically or manually, to allow for stepless stroke adjustment and to compensate for tolerances. Alternatively or additionally, plungers of different lengths can be used in the pneumatic actuator to achieve a specific stroke. The stroke is defined as the distance the piston or plunger travels in the pneumatic actuator during an upward and downward movement.

The actuator stroke, or plunger stroke, can be determined, for example, by the viscosity of the metering medium. For very low-viscosity media, a plunger stroke of at least 50 µm and/or at most 150 µm may be preferred. For high-viscosity media, where significantly higher plunger speeds are required, the plunger stroke can range from 0.5 mm to several millimeters. Accordingly, the plunger stroke can be up to 2 mm, optionally up to 5 mm. A minimum plunger stroke can be approximately 50 µm.

The displacement volume of each actuator chamber to be filled depends, among other things, on the set stroke and can be changed accordingly by the position of the stroke stop. For example, with relatively small strokes, e.g., 50 µm, the displacement volume can be approximately 0.8 ^mm³ . With larger strokes, e.g., 2 mm, the displacement volume can be 33 ^mm³ , and with strokes of 5 mm, the displacement volume can be 84 ^mm³ .

According to one embodiment, the pneumatic actuator can have a plunger guide (or guide area) for guiding the plunger during operation, i.e., during movement. This plunger guide is realized (only) by means of the piston and/or the cylinder. A plunger guide is generally understood to be a device or construction that enables or causes the intended (longitudinal) movement of the plunger during operation, particularly for dispensing metering fluid. The plunger guide ensures, in particular, that the plunger tip is aligned concentrically to the nozzle and/or a nozzle insert during operation. Preferably, the plunger guide can be realized exclusively by the piston and the (hollow) cylinder. It is possible that the plunger guidance during operation is realized by means of only a single plunger guide formed by the piston and/or the cylinder, particularly through an interaction of the piston and cylinder. In other words, the plunger can be guided only by the piston (or two pistons) in the cylinder during operation. It is particularly possible that, during operation, the plunger only has direct contact with the pneumatic actuator material in the area of the plunger guide, i.e., along the (hollow) cylinder. It is possible that outside the cylinder there is no direct contact between the plunger and the pneumatic actuator and/or actuator module (apart from the plunger tip). The plunger can have two spaced-apart pistons at its end, pointing away from the plunger tip. A material recess can be provided between the pistons. Accordingly, the plunger guide can be realized (only) by the two pistons in combination with the cylinder. Preferably, during operation, the respective outer surfaces of the pistons, i.e., the sides of the two pistons that point away from each other, can be pressurized with the pressure medium.

Advantageously, the pneumatic actuator can be designed to be particularly small because additional guide elements outside the cylinder, especially along the pushrod, can be omitted. This also allows the pushrod to be particularly short. This compact design enables the use of a particularly lightweight plunger, resulting in high dynamics. By implementing two guide points or positions (within the same plunger guide) using the two pistons, two sealing points are created in the pneumatic actuator, reducing compressed air consumption. A further advantage is that the risk of double fitting is avoided, simplifying manufacturing. The pneumatic actuator according to this embodiment can be combined with other embodiments of the invention, particularly with end-position seals.

According to one embodiment, the fluidic unit can have a metering seal that forms a further (second) plunger guide or a guide area for guiding the plunger during operation. The actuator module for guiding the plunger during operation can then have the plunger guide of the metering seal and a further plunger guide realized by means of the piston and/or the cylinder. In this embodiment, the plunger can, in principle, have two pistons, with one piston being preferred. It is possible that the plunger is guided during operation only by means of the (second) plunger guide of the metering seal and the (first) plunger guide realized by the piston and/or the (hollow) cylinder. Similarly, the plunger can be guided during operation only by the piston in the cylinder in combination with the metering seal. Additional guide elements can, in principle, be omitted. It is particularly possible that, during operation, the plunger only has direct contact with the material of the pneumatic actuator and/or actuator module in the area of the two plunger guides. Outside of this area, there is no direct contact between the plunger and the pneumatic actuator and/or actuator module (apart from the plunger tip). The actuator module according to this embodiment can be combined with other embodiments of the invention, in particular with the end-position seals. Such a metering seal, which provides a (second) plunger guide, can generally be part of a fluidic unit, in particular regardless of the specific design of the (rest of the) fluidic unit. For example, it is possible that the fluidic unit has only one channel for the medium, which opens into a nozzle chamber. It is also possible that the fluidic unit has two channels that open into a nozzle chamber and which can be separately supplied with medium.

Advantageously, a pneumatic actuator can be provided with the smallest possible installation space (height). A particularly short plunger can be used, resulting in the lowest possible moving mass and allowing for higher dynamics. The pneumatic actuator also has a simple design, which reduces manufacturing costs. Since the metering fluid seal is already integrated in many cases, additional guide elements can be omitted. In this embodiment, the plunger seal acts as the guide element. Furthermore, components can be manufactured with tighter tolerances because there is no risk of a double fit, as only two guide areas are present.

If the pneumatic actuator is part of an actuator module, the respective actuator module may preferably have a guide element, in particular an inlay, that forms a sliding surface for the pushrod. Such a guide element with a sliding surface can form a (further) pushrod guide for the plunger. Such a guide element, e.g., an inlay, can be implemented as an alternative or additional to the first and/or the second pushrod guide (as described above). The guide element can be designed such that a sliding surface is assigned to only a specific portion of the pushrod, relative to its longitudinal extent. The guide element is preferably sleeve-shaped and fully encloses the pushrod at least along a portion of its longitudinal extent. Preferably, the guide element is designed such that the piston, the metering fluid seal, and the plunger tip are not surrounded by the guide element.

The guide element can be at least partially arranged within the housing of the pneumatic actuator and can form part of an inner wall of the cylindrical housing. Preferably, the guide element is pressed into the pneumatic actuator, particularly into the cylindrical housing. Preferably, another part of the guide element, which is not located within the housing of the pneumatic actuator, can be arranged within the fluidic unit.

Preferably, the pneumatic actuator is designed such that the distance between an inner wall of the guide element and an outer surface of the pushrod changes at least once along the longitudinal extent of the pushrod. Preferably, in one section of the pushrod, the distance between the pushrod and the guide element can be at most 10 µm, preferably at most 5 µm, and more preferably at most 3 µm. Preferably, in another section of the pushrod, particularly along the running surface of the pushrod, the distance between the pushrod and the guide element can be at most 1000 µm, preferably at most 500 µm, and more preferably at most 300 µm. It is possible that the pushrod, with its running surface, makes direct contact with the guide element, particularly in the area of a sliding surface of the guide element.

Alternatively or additionally, the guide element is made of a material selected from cemented carbide and/or sapphire and/or ruby and/or ceramic and/or mixtures thereof. Preferably, such a material is present specifically (only) in the area of the sliding surface of the guide element, with other areas of the guide element consisting of a different material. It is also possible for the entire guide element to consist of one of the aforementioned materials. Preferably, the running surfaces of the pushrod, i.e., the areas that may come into contact with an inner wall of the guide element during operation, and the sliding surfaces of the guide element, i.e., the areas that may come into contact with the pushrod during operation, may have compatible materials. Preferably, at least the running surfaces of the pushrod and the sliding surfaces of the guide element may both be made of cemented carbide. It is also possible for at least the running surfaces of the pushrod to be made of cemented carbide, with the sliding surfaces of the guide element being made of sapphire.

Advantageously, the guide element can form a plunger guide, thus further improving concentricity between the plunger tip and the nozzle opening, particularly with delicate plunger rods. The use of hard metal contributes to a reduction in wear in this area of the pneumatic actuator. It should be noted that the described guide element is not limited to an actuator module but can also be used independently in a pneumatic actuator according to the invention.

The respective actuator module preferably comprises a fluidic unit that connects to the pneumatic actuator in the direction of the plunger tip. The fluidic unit itself can have a cylindrical section and can accommodate and completely enclose a portion of the plunger rod, particularly the plunger tip. This means that the cylindrical section of the fluidic unit can form an extension of the cylindrical housing of the pneumatic actuator, terminating with the nozzle of the fluidic unit. Preferably, the cylindrical section of the fluidic unit can at least partially surround the guide element of the pneumatic actuator. Accordingly, the guide element can be arranged both in the pneumatic actuator and in the fluidic unit. Preferably, the cylindrical section of the fluidic unit can be located externally. The pneumatic actuator and fluidic unit are slid onto the guide element and can optionally be detachably attached to the pneumatic actuator to form the actuator module. This means that the pneumatic actuator and the fluidic unit form a single, integrated unit (one module) during operation, although the components can, in principle, be separated from each other.

The fluidic unit can have two separate channels, each opening into a nozzle chamber within the unit and allowing separate flow of a medium. Each channel is preferably a bore with a media connection at its end, particularly for coupling to a module carrier. The nozzle chamber is formed within the fluidic unit and comprises the nozzle with an internal nozzle insert. During operation, the plunger tip projects into the nozzle chamber and can be pressed into the nozzle insert to eject metering fluid and/or close the metering valve. The terms metering fluid and metering medium are used synonymously in this description.

Advantageously, the fluidic unit, and in particular the nozzle insert, can be flushed with a solvent via the two channels without having to disconnect the fluidic unit from the pneumatic actuator or the metering valve. This can be done, for example, during production breaks. One channel can serve as a supply for a flushing medium, which flows through the fluidic unit and out through the other channel, which is temporarily connected to a disposal container, for example. During metering operation, both channels can be supplied with metering fluid and feed it to the nozzle chamber. Furthermore, the two channels can also be used to flush the fluidic unit with metering fluid, for example, shortly before the start of a metering process to remove air from the system. A continuous flow of metering fluid can also be advantageously generated in the fluidic unit, even during short metering breaks, thus preventing sedimentation. Furthermore, the two channels can be used to temperature control at least parts of the fluidic unit using the dosing fluid.

The respective actuator module can be coupled or connected to a module carrier, particularly in a detachable manner, to form a metering valve. For example, one actuator module can be installed in each module carrier. Each module carrier is associated with at least one pneumatic valve, preferably a 5/2-way valve, and a media supply, and preferably also with a control unit for controlling the operation of the pneumatic actuator. The module carrier is preferably designed to connect the respective actuator module to at least one pneumatic valve and a media supply to enable the intended operation of the actuator module.

The respective module carrier preferably comprises several channels for supplying compressed air separately to the first and second actuator chambers of the respective pneumatic actuator. Furthermore, the module carrier comprises at least one channel, preferably two channels, for supplying metering fluid to the fluidic unit of the connected actuator module. The module carrier can also include fastening means to hold the actuator module in a specific position during operation, particularly in conjunction with the pneumatic valve and the media supply. The respective module carrier can be implemented wholly or partially by means of a metering head supply element. In this case, several module carriers can be provided by means of a (common) supply element. This means that the supply element performs some or all of the functions of the module carriers. Alternatively, it is also possible for a module carrier to be designed independently of a supply element and/or a metering head, whereby a single metering valve can be provided by coupling an actuator module to a module carrier (e.g., for stand-alone operation).

The media supply, also referred to as the media supply unit, comprises – regardless of the specific design of the actuator module – preferably a storage or reservoir for metering fluid and means for introducing the metering fluid into the respective assigned channel of a specific module carrier and/or a specific fluidic unit of an actuator module. The metering fluid can preferably be supplied to the fluidic unit at a specific (over)pressure and/or at a specific temperature.

The media supply unit can include additional elements adapted to the respective actuator module. For example, the media supply unit can have connections that can be coupled to a respective module carrier to supply the fluidic unit connected to that module carrier with metering fluid. In the case of a metering head with multiple actuator modules, the media supply unit can be connected to a supply element of the metering head to supply metering fluid to the respective actuator modules via channels in the supply element. The supply element can have one or more media connections that can be connected to the metering fluid reservoir and/or to a waste container for the fluid. The media supply unit can The controllable system must be designed so that all actuator modules of a dosing head receive the same dosing medium and/or so that the supply of dosing medium to each actuator module is controlled separately. The media supply unit may also be designed to supply a cleaning fluid to the supply element, in particular to flush the respective fluidic unit with cleaning fluid.

The elements of a module carrier can be spatially spaced apart from one another. For example, the respective actuator module can be spatially separated from the pneumatic valve and/or the control unit and/or a metering fluid reservoir. Similarly, the respective metering valve can also have several elements that are spatially separated from one another and interact to form the metering valve. Furthermore, it is possible for elements of a module carrier to be assigned to several actuator modules and/or metering valves simultaneously. In particular, a pneumatic valve can be assigned to two or more actuator modules and/or several metering valves in parallel. This can be particularly advantageous in a metering head with several actuator modules, as described below, although the invention is not limited thereto.

A preferred dispensing head can have at least one pneumatic valve that is assigned to two or more actuator modules simultaneously or in parallel to operate the respective pneumatic actuator. This advantageously allows for a high density of actuator modules, as pneumatic valves require comparatively more space than actuator modules. Since each actuator module can generate a dispensing point during operation, this enables a particularly high point density. Depending on the dispensing requirements, it is possible to trigger all pneumatic valves of a dispensing head simultaneously, as all dispensing valves are intended to dispense concurrently, allowing for relatively simple control. Alternatively, it is also possible for each actuator module of a dispensing head to be assigned its own pneumatic valve and/or for the respective pneumatic valves of a dispensing head to be controlled separately.

The metering head can optionally include at least one pneumatic rotary valve to supply at least one pneumatic actuator of an actuator module with compressed air. Preferably, two or more pneumatic actuators can be supplied with compressed air simultaneously or in parallel via one rotary valve. The respective rotary valve is preferably a 5/2-way valve. A rotary valve is defined as a valve in which a roller with cross-connections in the form of channels rotates at a constant speed within a housing, with different channels being switched (i.e., temporarily opened or closed) per revolution. Each actuator chamber of a pneumatic actuator is assigned two channels in the rotary valve, which alternately connect to the respective actuator chamber to either fill or vent it. It should be noted that a rotary valve is not limited to the metering head. Rather, the use of a roller valve for operating a pneumatic actuator constitutes an independent aspect of the invention. Accordingly, a roller valve can be used in combination with various pneumatic actuators, e.g., with known pneumatic actuators. It is therefore particularly possible that the roller valve is designed to operate a pneumatic actuator that has a multi-part plunger and/or a piston with a piston seal.

Advantageously, a rotary valve allows for the rapid switching of relatively large channel diameters, enabling high flow rates and allowing the parallel operation of multiple actuator modules (or pneumatic actuators in general). Furthermore, the individual channels of the rotary valve, which close or open the metering valve, can be of different sizes to achieve varying closing and opening times. These channels can partially overlap or be spaced a defined distance apart. The latter allows for the venting of one actuator chamber before pressure builds up in the other. A rotary valve also allows for higher maximum metering frequencies than other 5/2-way valves, while simultaneously achieving high flow rates. It should be noted that a metering head can have different pneumatic valves. Furthermore, the described rotary valve can be used to supply a pneumatic actuator independently of a metering head. A preferred dispensing head comprises a separate holder for each actuator module, enabling the actuator module to be detachably mounted on the dispensing head. The holders are preferably arranged spatially on the dispensing head such that a specific dispensing pattern is achieved. One actuator module can be provided for each dispensing point. The respective holder can be provided by the module carrier, with each actuator module being connectable to a module carrier. Preferably, the dispensing head can have one or more mounting plates with a plurality of recesses or bores, wherein one actuator module can be arranged in each recess, particularly detachably. The respective mounting plate can be part of the supply element. The dispensing head can have two or more, optionally separate, mounting plates. each holding several actuator modules. This allows the actuator modules of a specific mounting plate to be replaced independently of other actuator modules of the dosing head.

The supply element can include multiple pneumatic valves. These can be mounted externally on the supply element and/or housed within the dosing head. The pneumatic valves are preferably connected to a control unit and a compressed air supply. The control unit can be part of a dosing head. For example, the control unit can include a circuit board located on or within the supply element and connected to the respective actuator modules. The supply element can also be connected to the media supply, such as an external dosing fluid tank. Furthermore, the supply element can have a controllable heating element to heat the fluid units of the respective actuator modules. For example, the supply element can have a central heating element to heat the dosing fluid to a set temperature in all fluid units, such as all nozzle chambers.

According to one embodiment, at least one actuator module or several actuator modules of a dispensing head can have pneumatic pilot control. Preferably, each actuator module, or only a specific group of actuator modules, is assigned pneumatic pilot control, which is controlled by at least one (or more) central pneumatic valve. The central pneumatic valve can be part of the dispensing head. The design allows for a pneumatic valve with a relatively low flow rate to provide pilot control for several actuator modules. The pneumatic pilot control can comprise one, preferably several, pneumatic actuators, each controlled by the central pneumatic valve. Each pneumatic actuator, in turn, switches (depending on the control by the central pneumatic valve) further pneumatic outputs or channels to operate an associated actuator module and/or an associated pneumatic actuator. It is possible for one pneumatic actuator to be assigned to two or more actuator modules and/or pneumatic actuators simultaneously. For example, the central pneumatic valve can form a pilot valve and the respective pneumatic actuator can form the main valve or actuating valve.

Advantageously, the number of pneumatic solenoid valves can be reduced. In extreme cases, a single pneumatic solenoid valve can be used for a dispensing head. This reduces costs. Furthermore, it is advantageous that the respective switching operation can be carried out as close as possible to the respective actuator module or pneumatic actuator via the pilot control, e.g., in direct proximity to the actuator module, which enables particularly fast switching times. It is possible for some actuator modules to have pneumatic pilot control while other actuator modules of the same dispensing head are supplied directly by a pneumatic valve.

Advantageously, an actuator module with pneumatic pilot control is not limited to a single dosing head. It is possible for each actuator module to have pneumatic pilot control independently of a dosing head. In particular, an actuator module with pneumatic pilot control can be sold and/or installed as a unit. For example, one or more actuator modules with pneumatic pilot control can be operated together using a pneumatic valve (independent of a dosing head).

Advantageously, each pneumatic actuator can have a pneumatic pilot control, particularly independent of an actuator module and/or a dosing head. In particular, a pneumatic actuator according to the invention can be sold and/or installed with a pneumatic pilot control (as a unit). For example, one or more pneumatic actuators assigned a pneumatic pilot control can be operated together by means of a pneumatic valve (independent of an actuator module and/or dosing head). The pneumatic pilot control can generally be configured as described above, particularly with regard to the pneumatic actuators and the central pneumatic valve.

The supply element can comprise two or more plates stacked horizontally on top of each other. Each plate can contain or form parts or sections of multiple channels. The channel sections can, for example, be milled into the plates. The plates are preferably arranged relative to each other, and in particular the channel sections of the respective plates are aligned with each other, such that functional channels for the metering fluid and/or pressure medium are formed to supply the actuator modules in the supply element. The individual plates are arranged like sandwich panels so that they seal against each other. Depending on the design of the metering head, a round supply element can be created by several, for example identical, sub-segments, each of which has a plurality of plates with integrated channels.

Alternatively or additionally, the supply element can be completely additively manufactured or at least have an additively manufactured part (3D printed part) with integrated channels for supply. The actuator modules are supplied, in particular for the delivery of dosing material and/or printing medium. Preferably, a 3D-printed part can also provide the respective holders to keep the actuator modules on the dispensing head during operation. Preferably, a component of the delivery element can be additively manufactured using stereolithography (SLA) or selective laser sintering (SLS). Suitable materials include plastics, e.g., polyetheretherketone, aluminum, stainless steel, and/or mixtures thereof.

Regardless of the specific design, the supply element is preferably configured such that each actuator module is supplied with metering fluid via at least one channel, preferably two channels. These channels of the supply element are also referred to as metering fluid channels. Preferably, all actuator modules of a metering head can receive the same metering fluid. The metering fluid channels can be part of the media supply system. The supply element further comprises channels for supplying each actuator module with compressed air during operation. These channels are also referred to as compressed air channels. Preferably, the supply element is configured such that one compressed air channel is provided for each actuator module for filling and/or venting the first actuator chamber, and a separate channel is provided for filling and/or venting the second actuator chamber. Preferably, each compressed air channel is connected to a working port of a pneumatic valve.

Preferably, the air distribution channels (compressed air channels) in the supply element are designed such that a single pneumatic valve supplies two or more actuator modules with compressed air, in particular simultaneously.

Preferably, the supply element is configured such that two or more compressed air channels, each assigned to a first actuator chamber of different actuator modules, branch off from or originate in a common (main) channel, wherein the (main) channel is connected at its end to a working port of a pneumatic valve and can be pressurized with compressed air. Alternatively or additionally, the supply element is configured such that two or more compressed air channels, each assigned to a second actuator chamber of different actuator modules, branch off from or originate in a common (main) channel, wherein the (main) channel is connected at its end to a working port of a pneumatic valve and can be pressurized with compressed air. For example, each (main) channel can be divided into four or more individual compressed air channels. Advantageously, this allows several actuator modules to be operated by means of the same pneumatic valve, whereby the (main) channel can be divided as close as possible to the assigned actuator modules, which can simplify the manufacture of the supply element. Another advantage is that all compressed air channels assigned to a pneumatic valve can have the same length, resulting in identical dynamic behavior and delay for the relevant actuator modules. This can have a beneficial effect on comparable dosing.

The supply element can be designed such that the respective actuator modules are at least partially located within the supply element itself during operation, i.e., section by section, integrated into it. For example, it is possible that the (entire) pneumatic actuator is located within the sandwich panels and/or in a 3D-printed unit, with only the fluidic unit protruding from the supply element, possibly only the nozzle. It is also possible that a respective actuator module is located entirely within the supply element, with the nozzle being flush with an outer surface of the supply element.

The spatial arrangement of the actuator modules on the dispensing head is preferably determined by the desired dispensing pattern. Accordingly, asymmetrical (dispensing) patterns are also possible. If an application requires separate control of each actuator module, each actuator module or specific actuator modules can be assigned their own pneumatic valve. The respective pneumatic valves can be operated separately by means of a control unit. It is also possible to supply different dispensing materials to different actuator modules. Advantageously, this allows for the dispensing of any desired and even complex patterns, particularly in combination with a movable dispensing head.

A supply element preferably comprises at least one plate, e.g., a milled part, and at least one additively manufactured part. Preferably, one part of the supply element, comprising the compressed air channels, can be an additively manufactured component. Correspondingly, another part of the supply element, comprising the metering channels, can be a milled part. Such a milled part can be made of plastic, in particular polyetheretherketone. A milled part, preferably consisting of a (single) plate with integrated metering channels, preferably forms a media distributor for supplying a plurality of actuator modules. Thus, the supply element can preferably be multi-part and/or comprise parts made of different materials. It is also possible for a supply element to comprise two or more plates, e.g., milled parts. and/or features two or more separately manufactured 3D printed parts that work together to provide the supply element.

The use of an additively manufactured supply element allows for particularly flexible routing of (all) channels within the supply element. This enables the actuator modules to be arranged even more individually relative to each other on the dispensing head, e.g., even at very small intervals. Furthermore, 3D printing offers the advantage of optimizing the air channels from a flow perspective. For example, curved paths and/or trumpet-shaped transitions can lead to higher performance. Advantageously, the respective channels can be essentially the same length, which is important for comparable dispensing. Additionally, the choice of material for 3D printing can ensure exceptional media resistance.

It is possible for a pneumatic valve and the associated compressed air channels for supplying at least one actuator module to form a pneumatic module. Preferably, such a pneumatic module can have an additively manufactured base body and a pneumatic valve interacting with it. The pneumatic valve can be arranged at least partially within the additively manufactured part, e.g., inserted. The pneumatic module can preferably be detachably coupled to other, particularly identical, pneumatic modules and/or can be detachably coupled to a media distributor comprising metering channels to form a supply element. The media distributor can be a milled part.

It is preferred that each pneumatic module comprises two or more pneumatic valves and is designed such that two or more actuator modules can be supplied with compressed air during operation. For example, a pneumatic module can have two pneumatic valves, with compressed air channels for supplying four actuator modules (per pneumatic valve) being formed in the additively manufactured base body. The additively manufactured part of the pneumatic module preferably has a recess for each (to be coupled) actuator module, into which at least the area of the respective pneumatic actuator with the first and second pressure chambers can be received. The fluidic unit of the respective actuator module can preferably be received in a recess in the media distributor. Advantageously, a metering head can have one or more such pneumatic modules that are detachably connected to it. This simplifies the disassembly of the actuator modules, e.g. for maintenance, by separating the relevant pneumatic module as a unit from the rest of the supply element or the dosing head.

Depending on the dispensing requirements, several actuator modules can be arranged in a row on the dispensing head. Consequently, the dispensing head is not limited to round shapes but can have various designs. Even with a linear arrangement, each actuator module can be assigned its own pneumatic valve, for example, to dispense samples or to allow the dispensing head to be tilted relative to its direction of movement. A linear arrangement of the actuator modules may be desirable, for example, in painting applications.

It is possible for two or more actuator modules to be combined into a single assembly. This assembly can include a corresponding number of module carriers to supply the actuator modules with compressed air and metering medium during operation. The module carriers can be implemented as a supply element, for example, as previously described using a metering head.

For example, four module carriers can be combined into a single unit. Such an actuator module assembly can have a single pneumatic valve or a separate pneumatic valve for each actuator module. Preferably, several such assemblies can be combined for a dispensing process. For example, several actuator module assemblies can be connected in series. Advantageously, a dispensing head and/or a supply element can consist of several units (actuator module assemblies) that can be combined or coupled together during operation. This allows for flexible adaptation to specific dispensing requirements. The individual actuator modules can preferably have a constant distance from each other. Such a linear arrangement can be useful for painting tasks, e.g., for large-area coatings.

• 1 und 2 im Schnitt dargestellte Ansichten von Aktormodulen gemäß der Erfindung,
• 3 eine im Schnitt dargestellte Ansicht von Teilen eines Pneumatikaktors gemäß der Erfindung und zwei vergrößerte Ausschnitte,
• 4 im Schnitt dargestellte und teilweise vergrößerte Ansichten von Teilen eines Pneumatikaktors gemäß der Erfindung,
• 5 eine im Schnitt dargestellte Ansicht eines Aktormoduls gemäß der Erfindung,
• 6 bis 8 im Schnitt dargestellte Ansichten von Teilen von Pneumatikaktoren gemäß der Erfindung,
• 9 und 10 perspektivische Ansichten von Dosierköpfen gemäß der Erfindung,
• 11 und 12 perspektivische Ansichten von Teilen von Dosierköpfen gemäß der Erfindung,
• 13 eine Ansicht eines Teils eines Dosierkopfs gemäß der Erfindung,
• 14 und 15 Ansichten von Aktormodulbaugruppen mit Aktormodulen gemäß der Erfindung,
• 16 und 17 Ansichten von Pneumatikaktoren gemäß der Erfindung mit Walzenventilen,
• 18 bis 22 Ansichten, teilweise im Schnitt, von Dosierköpfen gemäß der Erfindung,
• 23 eine Ansicht eines Teils eines Dosierkopfs gemäß der Erfindung,
• 24 eine im Schnitt dargestellte Ansicht eines Aktormoduls gemäß der Erfindung,
• 25 eine im Schnitt dargestellte Ansicht eines Aktormoduls gemäß der Erfindung.

The invention is explained in more detail below with reference to the accompanying figures and exemplary embodiments. The same components are designated with identical reference numerals in the various figures. The figures are generally not to scale. They schematically show:

• 1 and 2 Sectional views of actuator modules according to the invention,
• 3 a cross-sectional view of parts of a pneumatic actuator according to the invention and two enlarged sections,
• 4 Sectional and partially enlarged views of parts of a pneumatic actuator according to the invention,
• 5 a cross-sectional view of an actuator module according to the invention,
• 6 to 8 Sectional views of parts of pneumatic actuators according to the invention,
• 9 and 10 perspective views of dosing heads according to the invention,
• 11 and 12 perspective views of parts of dosing heads according to the invention,
• 13 a view of part of a dosing head according to the invention,
• 14 and 15 Views of actuator module assemblies with actuator modules according to the invention,
• 16 and 17 Views of pneumatic actuators according to the invention with roller valves,
• 18 to 22 Views, some in section, of dosing heads according to the invention,
• 23 a view of part of a dosing head according to the invention,
• 24 a cross-sectional view of an actuator module according to the invention,
• 25 A cross-sectional view of an actuator module according to the invention.

In 1 and 2 Each figure schematically shows an actuator module according to the invention, wherein 2 an exploded view of the actuator module from 1 The actuator module 3 comprises a pneumatic actuator 1 and an associated fluidic unit 30. In this example, the pneumatic actuator 1 and the fluidic unit 30 are manufactured as separate components that are inserted into one another to form the actuator module 3 and are firmly connected to each other. The pneumatic actuator 1 comprises a housing 17. Inside the housing 17, a cylinder 10, or a hollow cylinder 10, is formed, wherein a piston 20, also referred to as a pneumatic piston, can be moved up and down in opposite directions R within an interior 10" of the hollow cylinder 10. The hollow cylinder 10 of the pneumatic actuator 1 is limited at the top by a stop 11, also referred to as a stroke stop 11, of the pneumatic actuator 1. The stroke stop 11 also has a hollow cylinder 12, which has a free space in the center for the flow of pressure medium DL, or compressed air DL.

The pneumatic actuator 1 has a plunger 2 with an elongated plunger rod 22, which is rigidly connected to the piston 20 on one side. The plunger rod 22 and the piston 20 are manufactured as a single unit, so that the plunger 2 is a single, monolithic component. The plunger rod 22 extends from the piston 20 to an end plunger tip 25. The plunger tip 25 is located in a nozzle chamber 36, which contains metering fluid DS during operation (not shown). The nozzle chamber 36 is bounded at the top by a metering fluid seal 26, which completely surrounds the plunger 2 in one section. A drainage opening 27 is located above the metering fluid seal 26 to allow the escape of metering fluid DS in the event of a leak in the metering fluid seal 26.

In 2 It can be seen that the nozzle chamber 36 is part of the fluidic unit 30 and is bounded downwards by a nozzle 37, which has an internal nozzle insert 37'. For supplying metering fluid DS (not shown) into the nozzle chamber 36, the fluidic unit 30 has a channel with a media connection 39 at its end. The fluidic unit 30 can be connected to a media supply (not shown) via the media connection 39. The fluidic unit 30 comprises a cylindrical part 38, which forms an interior space for receiving the plunger 2 and other parts of the pneumatic actuator 1. The cylindrical part 38 can be slid onto the lower part of the pneumatic actuator 1, parallel to the longitudinal extent of the plunger 2, to form the actuator module 3. This allows parts of the plunger 2, e.g. the plunger tip 25, and parts of a guide element 31 of the pneumatic actuator 1, to be accommodated in the cylindrical part 38 of the fluidic unit 30.

In 2 The hollow cylinder 10 is shown at the upper end of the pneumatic actuator 1, wherein the hollow cylinder 10 has a free interior 10" in which the piston 20 is movably mounted, and is bounded by an inwardly facing wall 10'. In the assembled state of the pneumatic actuator 1, the stroke stop 11 extends into the interior 10" of the hollow cylinder 10 ( 1 Unlike what is shown here, the position of the stroke stop 11 in the housing 17 of the pneumatic actuator 1 can be changed. The stroke stop 11 in turn comprises a hollow cylinder 12 with a freely flowing interior 12" ( 3 ), wherein a wall 12' of the hollow cylinder 12 forms a sealing element 13 at an end pointing downwards towards the piston 20. This is demonstrated by 3 described in more detail.

3 Figure 1 schematically shows a cross-section through a pneumatic actuator according to the invention and parts of a fluidic unit, as well as two enlarged sections of the pneumatic actuator. The pneumatic actuator 1 is constructed as shown in Figure 1. 1 and 2 as described. The enlarged section at the top right shows an example of a first operating state of the pneumatic actuator 1, with the piston 20 in a first end position EP. In the end position EP, the piston 20 rests against the stroke stop 11. To move the piston 20 into this end position EP, i.e., for an upward movement of the piston 20, compressed air DL is introduced into a second actuator chamber 16, which is located below the piston 20. The compressed air DL directly impacts a side 21' or surface 21' of the piston 20. Simultaneously, compressed air DL flows out of a first actuator chamber 15, which is located above the piston 20. The flow of the compressed air DL is symbolized by arrows. This configuration of the pneumatic actuator 1 moves the piston 20 upwards in the direction R.

The upward movement of the piston 20 is terminated when a side 21 or surface 21 of the piston 20 abuts the downward-facing end of the wall 12' of the stroke stop 11. The (end) region of the wall 12' facing the piston 20 forms a sealing element 13. In the end position EP shown here, the side 21 of the piston 20 rests against the sealing element 13, creating a seal. Accordingly, in the first end position EP, a substantially airtight connection can be formed between the piston 20 and the inner wall 10' of the hollow cylinder 10 of the pneumatic actuator 1 by means of the sealing element 13. This ensures that the first actuator chamber 15 is substantially airtight from the second actuator chamber 16, and that, when the second actuator chamber 16 is filled, as little compressed air DL as possible escapes unused, even though the piston 20 is mounted without a seal in the hollow cylinder 10. The inset at the top right indicates that the piston 20 has no seal in area B, which corresponds to a longitudinal extension of the piston 20, in particular no piston seal. The seal-free mounting of the piston 20 is shown in 4 shown in detail using a different embodiment.

4 This schematically shows parts of sectional views of a pneumatic actuator. The right-hand section shows an enlarged section of pneumatic actuator 1, while the enlarged section (in the left-hand part of) 4 ) is marked with a dashed line. In the enlarged section (right part of 4 It can be seen that a free gap SP exists between an outer surface of the piston 20 and the inner wall 10' of the hollow cylinder 10 of the pneumatic actuator 1. This gap SP can be filled with compressed air DL, at least during an upward and downward movement of the piston 20. Accordingly, compressed air DL can flow through the gap SP from one side of the piston 20 to the other. The gap SP is preferably formed along the entire longitudinal extent of the piston 20, since the piston 20 is arranged without a seal in the hollow cylinder 10.

In 3 The enlarged section at the bottom right shows another operating state of the pneumatic actuator 1, with the piston 20 in a second end position EP'. This end position EP' is characterized by the plunger tip being pressed into the sealing seat of the nozzle (not shown), with a corresponding metering valve closed. To move the plunger from the first end position EP to the second end position EP', i.e., for a downward movement of the piston 20 in the direction R, the first actuator chamber 15 can be filled with compressed air DL. For this purpose, the upward-facing side 21 of the piston 20 can be directly pressurized with compressed air DL. Simultaneously, compressed air DL can flow out of the second actuator chamber 16. When the piston 20 is in the second end position EP', the downward-facing side 21' of the piston 20 directly contacts a second, elastic sealing element 14. By means of the second sealing element 14, an essentially airtight connection can be formed between the piston 20 and the inwardly facing wall 10' of the hollow cylinder 10. This means that no compressed air DL is consumed when the metering valve is closed.

In 5 Figure 1 shows a schematic view of an actuator module 3 comprising a pneumatic actuator 1 and an associated fluidic unit 30. The plunger rod 22 of the plunger 2 is partially arranged in a guide element 31. The guide element 31 is pressed into the housing 17 of the pneumatic actuator 1. The fluidic unit 30, with its cylindrical part 28, is pushed onto the guide element 31 and the housing 17 from the outside and is connected to the housing 17 of the pneumatic actuator 1. Accordingly, the guide element 31 is arranged in both the pneumatic actuator 1 and the fluidic unit 30. The guide element 31 serves as a plunger guide and can support a concentric alignment of the plunger tip 25 with respect to the nozzle insert 37'.

The pushrod 22 has different circumferences or diameters along its length. As a result, in one region B', there is a specific distance between an outer surface 22' of the pushrod 22 and an inner wall 33 of the guide element 31. In another region B'', which adjoins region B' towards the pushrod tip 25, and where the pushrod 22 has a larger diameter than in region B', the distance between the outer surface 22' of the pushrod 22 and the inner wall 33 of the guide element 31 is correspondingly smaller. It is also possible that the pushrod 22 makes direct contact with the guide element 31 in region B'' during an upward or downward movement. To minimize wear, the pushrod 22 can have a particularly wear-resistant material, e.g., a hard metal, in the area of its running surface 23, via which it may contact the guide element 31. Furthermore, the guide element 31 can have a particularly wear-resistant material in the area of a sliding surface 32, which may be contacted by the pushrod 22 during operation. The guide element 31 must be made of a resistant material. For example, the inner wall 33 of the guide element 31 in region B'' can be made of hard metal. The pushrod 22 has a coating 24 in the region of the plunger seal 26 to minimize wear. The pushrod 22 includes a further region B'', which is located below the piston 20 or extends from the piston 20 towards the plunger tip 25. In this region B'', the pushrod 22 has a larger diameter than in region B', with a correspondingly smaller distance between the outer surface 22' of the pushrod 22 and the inner wall 33 of the guide element 31. It is also possible that the pushrod 22 makes direct contact with the guide element 31 in the (upper) region B'' during an upward or downward movement. It is generally preferred that the two areas B'' with enlarged circumference and/or the corresponding contact areas with the guide element 31 are located as far apart as possible in order to prevent tilting or jamming of the plunger 2. This arrangement allows for more precise concentric guidance of the plunger 2.

The fluidic unit 30 comprises two separate channels 34 and 35, each with a media connection 39 at its end and leading into the nozzle chamber 36. During operation, the channels 34 and 35 can be used in parallel to supply metering fluid to the nozzle chamber 36. Furthermore, the channels 34 and 35 can be used to flush the fluidic unit 30, for example, to remove air. For this purpose, metering fluid can be passed through the nozzle chamber 36 via the channels 34 and 35. It is also possible to clean the fluidic unit 30, in particular the nozzle insert 37', using the channels 34 and 35, for example, by passing a cleaning medium through the nozzle chamber 36.

In 24 Figure 1 shows a schematic view of an actuator module 3 comprising a pneumatic actuator 1 and an associated fluidic unit 30. In this embodiment, unlike, for example, in Figure 2, the actuator module 3 is not connected to a pneumatic actuator 1. 5 No guide element is provided along the pushrod 22. The actuator module 3 is designed such that the plunger 2 is guided during operation only by the piston 20 in the cylinder 10 and by the metering seal 26 during its upward and downward movement. Accordingly, the interaction of the piston 20 and the cylinder 10 can form a first plunger guide, and the metering seal 26 can form a second plunger guide. It can be seen that the length of the plunger 2 (perpendicular to the piston 20) is considerably shorter than, for example, in 5 .

In 25 Figure 1 shows a schematic view of an actuator module 3 comprising a pneumatic actuator 1 and an associated fluidic unit 30. In this embodiment, unlike, for example, in Figure 2, the actuator module 3 is not connected to a pneumatic actuator 1. 5 and similarly 24 No guide element is provided along the pushrod 22. In this embodiment, the plunger 2 comprises two pistons 20, 20' which are spaced apart from each other. Accordingly, the cylinder 10 is also extended in the longitudinal direction of the plunger 2 (compared to an embodiment with only one piston 20). In this example, the guidance of the plunger during the upward and downward movement is achieved solely by the interaction of the two pistons 20, 20' with the cylinder 10. Thus, there is only a single plunger guide, which comprises two guide positions in the area of the two pistons 20, 20'. The metering fluid seal 26 does not play a significant role in guiding the plunger 2 in this example. In this embodiment as well, the length of the plunger 2 (transverse to the pistons 20, 20') is considerably shorter than, for example, in 5 The actuator modules 3 in 24 and 25 Apart from the special features concerning the plunger guide and the plunger 2, they can be constructed similarly or identically to, for example, the actuator modules in the 1 to 8 .

In 6 to 8 Schematic sectional views of parts of pneumatic actuators according to the invention are shown, wherein in these examples the pneumatic actuator comprises a diaphragm to further reduce compressed air consumption during operation. The diaphragm is shown here as an alternative to the second sealing element 14 in 3 planned. In 6 It is shown that the pneumatic actuator 1 comprises a housing 17 in which, among other things, a hollow cylinder 10 is formed in which the piston 20 is movably mounted in opposite directions R. A stroke stop 11 for the piston 20 is also arranged in the housing 17. The stroke stop 11 includes, among other things, a hollow cylinder 12 formed by a cylinder wall 12', the free end of which points towards the piston 20. An interior space 12'' is formed in the hollow cylinder 12 of the stroke stop 11, through which compressed air DL can flow during operation to fill or vent the actuator chamber 15. A diaphragm 5 is arranged on a side 21 of the piston 20 that points towards the stroke stop 11. The diaphragm 5 rests on the piston 20 or the plunger head and is not connected to the plunger head in this example. The diameter of the diaphragm 5 is larger than the diameter D of the piston 20. It can be seen that the diaphragm 5 is flat and very thin in order to achieve the lowest possible spring rate. The diaphragm 5 can, for example, be made of stainless steel.

In 7 Is pneumatic actuator 1 off? 6 The figure shows an operating state corresponding to a closed state of an associated metering valve, i.e., when the pneumatic actuator 1 is inserted in a metering valve. The first actuator chamber 15 is filled with compressed air DL, whereby in this case one side 50 of the diaphragm 5 is directly connected to Compressed air DL is applied instead of the piston 20. This causes the diaphragm 5 to move. 7 The diaphragm 5 is deflected or pressed downwards, causing the piston 20 to also move downwards in the direction R. A stop 52, located inside the pneumatic actuator 1, is associated with the diaphragm 5. The stop 52 is designed as a step connecting two sections of the hollow cylinder 10 with different diameters. Since the diameter of the diaphragm 5 is larger than the diameter D of the piston 20 and larger than the diameter of the hollow cylinder 10 in a constricted area below the stop 52 (pointing towards the pushrod 22), the diaphragm 5 is pressed towards the stop 52 by the application of compressed air DL and ultimately rests directly against it. Once the diaphragm 5 rests against the annular stop 52, it seals against it, essentially creating an airtight seal, with the diaphragm 5 in a sealing position DT. As a result of the application of compressed air DL, the diaphragm 5 deflects downwards in a central area, whereby the piston 20 is further deflected in the direction R by means of the diaphragm 5 and the plunger 20 is pressed into the nozzle insert (not shown). Advantageously, this ensures that no unnecessary compressed air DL is consumed in the closed position of the metering valve, since the diaphragm 5 is in the sealing position DT and the flow of compressed air DL past the piston 20 is prevented.

In 8 Is pneumatic actuator 1 off? 7 The figure shows a different operating state, corresponding to an open position of an associated metering valve. To move the plunger 2 upwards in the direction R to open the metering valve, the second actuator chamber 16 can be filled with compressed air DL, directly pressurizing the downward-facing side 21' of the piston 20 with compressed air DL. This moves the piston 20 towards the stroke stop 11, with the diaphragm 5, resting on top of the piston 20, moving together with the piston 20. The upward movement in the direction R is stopped as soon as the piston 20 is pressed against the stroke stop 11 via the diaphragm 5. Once the piston 20 indirectly rests against the stroke stop 11, the diaphragm 5 is in a position S that allows compressed air DL to pass from one side 51 to the other side 50 of the diaphragm 5. Arrows symbolize that compressed air DL can flow between the diaphragm 5, which is in position S, and the inward-facing wall 10' of the hollow cylinder 10. In position S shown here, the diaphragm 5 therefore has no sealing function. The stroke stop 1 has several recesses 53 in which the diaphragm 5 does not directly contact the stroke stop 11 and is spaced from it. These (material) recesses 53 allow compressed air DL to flow into the interior 12'' of the stroke stop 11, thus enabling a constant airflow and ensuring that the piston 20 is pressed against the stroke stop 11 (indirectly via the diaphragm 5).

In 9 and 10 Perspective views of dispensing heads according to the invention are shown. Each dispensing head 9 comprises a plurality of actuator modules 3 arranged on two concentric circles. The actuator modules 3 are held in retaining plates 97 of a supply element 90 and are arranged according to the dispensing pattern. One actuator module 3 is provided per dispensing point. It can be seen that parts of each actuator module 3 are located inside the supply element 90. During operation, the actuator modules 3 are supplied with compressed air and dispensing fluid via the supply element 90. The supply element 90 comprises four plates 93, or sandwich plates, by means of which channels for compressed air and dispensing fluid are formed.

10 shows another view of the dosing head 9 from 9 It can be seen that the supply element 90 includes a media supply 8, which, via channels inside the supply element 90, supplies the respective actuator modules 3 with metering fluid. The media supply 8 includes connections that can be connected, for example, to an external metering fluid supply and a metering fluid reservoir (not shown). In this example, 24 pneumatic valves 7 are arranged on the supply element 90. Each pneumatic valve 7 is assigned to four actuator modules 3 to supply them simultaneously with compressed air. Accordingly, each pneumatic valve 7 is connected to four individual actuator modules 3 via the compressed air channels in the supply element 90. The pneumatic valves 7 are 5/2-way solenoid valves. Details of the pneumatic valves 7, such as the electrical supply and the connection to an external compressed air source, are not shown here.

In the 11 and 12 Schematic views of parts of dosing heads according to the invention are shown, e.g. the dosing head made of 9 In 11 and 12 Some parts of the supply element 90 are shown transparently in order to show the channels inside the supply element 90 as far as possible. 11 A partial segment of a dosing head 9 is shown, comprising three pneumatic valves 7 and 12 actuator modules 3, which are only partially visible. The actuator modules 3 are each arranged in a mounting plate 97 of the supply element 90. In this example, each mounting plate 97 holds four actuator modules 3. This allows the respective actuator modules 3 to be replaced independently of the other actuator modules 3 of the dosing head. The supply element 90 includes a media supply 8, with two connections for an external metering agent supply shown here. A channel 91, also referred to as a metering agent channel, is connected to each connection of the media supply 8 inside the supply element 90. This channel runs predominantly vertically through the individual plates 93 of the supply element 90. This means that the individual plates 93 comprise a section of the channel 91 and interact to form the complete channel 91. The plates 93 seal against each other. Inside the supply element 90, each channel 91 divides into several channels 91' (in 11 (not visible in detail), e.g. in six channels 91', each channel 91' being connected to a fluidic unit 30 of an actuator module 3.

The supply element 90 is designed such that each pneumatic valve 7 is connected to two channels 96 in the supply element 90, wherein in 11 For technical reasons, only one channel 96 is visible at a time. These channels 96, or compressed air channels, are designed to supply the actuator modules 3 with compressed air and to switch the pneumatic actuators accordingly. This is demonstrated by 12 described in more detail.

In 12 is the sub-segment of the dosing head 9 made of 11 The diagram shows a top view, with the uppermost plate 93' of the supply element 90 shown transparently. Each pneumatic valve 7 is connected to two separate channels 96, 96', or compressed air channels, in the supply element 90. Each channel 96 is connected to a working port of the respective pneumatic valve 7 and runs predominantly vertically through the plates 93', 93 downwards, supplying the second actuator chamber of the pneumatic actuators of the actuator modules 3. The channel 96 divides into four individual channels in one of the lower plates 93, i.e., in a plane below the plate 93 visible here. Of these channels, which are not visible here for technical reasons, each channel is assigned to a specific actuator module 3.

In the second plate 93 of the supply element 90, the other compressed air channel 96', which is assigned, for example, to the middle pneumatic valve 7, divides into four individual channels 92'. Each channel 92' is assigned to a different actuator module 3 to supply the first actuator chamber of the pneumatic actuators of the actuator modules 3 with compressed air. The compressed air channel 96', which is also referred to as the (main) channel, runs downwards in the visible plate 93 and is connected to a working port of the middle pneumatic valve 7. It should be noted that preferably each compressed air channel 96' of the supply element 90 is configured in the manner described. Furthermore, the respective compressed air channel 96 for supplying the second actuator chamber can also divide into several channels in a comparable manner, but in a different level or plate of the supply element 90.

In 12 It is shown that each metering valve 4 comprises at least one actuator module 3, a media supply 8, and an associated pneumatic valve 7 as components. Furthermore, it can be seen that in this example, a respective module carrier 6 is provided by means of the supply element 90.

In 13 Figure 1 shows a schematic view of a portion of a dispensing head according to the invention, wherein in this example the supply element 90 comprises an additively manufactured part 94. The supply element 90 is shown predominantly transparent to reveal the internal channels as far as possible. The section of the supply element 90 shown includes a media supply 8 with two connections for connecting to an external supply of dispensing material. A channel 91 extends downwards from each connection within the supply element 90 to supply two actuator modules 3 with dispensing material.

To supply the pneumatic actuators of the actuator modules 3, two compressed air channels 96, 96' are arranged in the supply element 90, which are also referred to as (main) channels, each channel 96, 96' being connected to a working end of the same pneumatic valve. The pneumatic valve is in 13 not shown and could, for example, be located on the rear of the supply element 90. A first channel 96 divides into two separate channels 92, which run downwards parallel to a longitudinal extension of the actuator modules 3. Each of these two channels 92 is connected to two actuator modules 3 to fill the respective second actuator chamber with compressed air, so that the plunger of the actuator modules 3 moves upwards and a nozzle opening of the actuator modules 3 is exposed. Venting of the respective second actuator chamber can also occur via these channels. A second channel 96' divides into four channels 92', with each channel 92' being connected to an actuator module 3 to fill the first actuator chamber with compressed air, so that the plunger moves downwards and is pressed into the nozzle insert of the nozzle. Venting of the respective first actuator chamber is also possible via these channels. Channel 96' can, for example, run downwards from the branching point and be connected to a working port of the pneumatic valve below the other channel 96. 13 Further bores 95 are shown in the supply element 90, which are used, for example, for coupling the supply element. 90 are provided with other parts of the dosing head 9.

14 and 15 show schematic views of actuator module assemblies with actuator modules according to the invention, wherein in 14 A supply element 90 is shown partially transparently. The actuator module assembly 9' in 14 The system comprises four actuator modules 3, which are partially arranged and held within the supply element 90. The actuator modules 3 are arranged linearly. The supply element 90 includes a connection for a media supply as part of a media supply 8, wherein a channel 91, or metering fluid channel, extends towards the fluid units 30 to supply each of them with metering fluid DS. Shortly before reaching the fluid units 30, the channel 91 divides into four channels 91'.

In 14 An example of a pneumatic valve 7, e.g., a 5/2-way valve, with two working ports 70, 71 is shown. A first working port 70 is connected to a channel 96, which is designed to supply the second actuator chamber of the pneumatic actuator in the actuator module 3 on the right with compressed air DL. The channel 96 includes an annular channel 96 that runs around the outside of the actuator module 3 to introduce compressed air DL into the second actuator chamber via bores. A second working port 71 is connected to a channel 96', which is designed to introduce compressed air into the first actuator chamber of the actuator module 3 on the right, e.g., via a cavity in the stroke stop. In the example shown, each actuator module 3 is assigned a separate pneumatic valve 7. Consequently, the connection of the remaining actuator modules 3 of the actuator module assembly 9' to the respective pneumatic valves 7 can be carried out in the manner described above. 14 It is further shown that the supply element has 90 connections 98 to supply the respective pneumatic valve 7 with compressed air DL.

In 15 Four actuator module assemblies 9' are shown, which are connected to each other and form a dosing head 9. The actuator module assemblies 9' are constructed as shown in the following: 14 as described. Such a dosing head 9 can be used, for example, for large-area coatings.

In 16 and 17 The diagram shows schematic and highly simplified views of pneumatic actuators with roller valves. 16 Figure 1 shows an operating state of the pneumatic actuator 1 in which the plunger 2 is moved downwards in the direction R. For this purpose, the first actuator chamber 15 is filled with compressed air DL. Simultaneously, the second actuator chamber 16 is vented. Unlike the purely schematic representation shown here, the first actuator chamber 15 is connected to a working port 106 of the roller valve 100. The second actuator chamber 16 is connected to a different working port 107. During operation, the roller valve 100 rotates at a constant speed in a housing 101 around its longitudinal axis, with different channels 102-105 being switched through with each revolution. 16 Currently, channel 102 is open, meaning it is being flowed with compressed air DL in the direction of the arrow. Simultaneously, channel 104 is open, with compressed air DL flowing out of the second actuator chamber 16. In a summary of 16 and 17 It is evident that the respective channels 102-105 have different widths or sizes, meaning they are open for different durations during operation of the roller valve 100 to allow the flow of compressed air DL. For example, channel 102, particularly its opening, is significantly wider than channel 103. As a result, the first actuator chamber 15 is filled with compressed air DL for a relatively long time and vented for only a relatively short time. Consequently, the plunger 2 is pressed downwards for most of the operation, with a corresponding metering valve closed. Similarly, channel 104 is also relatively wide, allowing compressed air DL to flow out through it for a relatively long period, thus venting the second actuator chamber 16 for a relatively long time. In contrast, channel 105, which fills the second actuator chamber 16, is relatively narrow. It should be noted that the use of roller valves for operating a pneumatic actuator is not limited to a specific type of pneumatic actuator.

In 18 to 22 The figures show schematic and partially sectional views of a dosing head according to the invention or parts thereof. In this example, the dosing head 9 has 72 actuator modules 3, which are detachably connected to the dosing head 9. The dosing head 9 has a multi-part housing 110 and has a connection 111 for the power supply and a connection 111' for the electrical supply of the pneumatic valves of the dosing head 9. The dosing head 9 has, among other things, a media distributor 113, e.g., a milled part, in the form of a plate with a plurality of internal dosing channels and four media connections 114, which are only partially visible. The media connections 114 and the media distributor 113 are parts of the supply element 90.

In 21 It can be seen that the media distributor 113 has four channels 116, 116' in the form of circular segments. Each media connection 114 is connected to two different channels 116, 116'. Accordingly, each actuator module is assigned two media connections 114 for its supply. For example, the leftmost media connection 114 can be used to introduce a cleaning medium into channel 116'. The cleaning medium can then be removed from channel 116' via the middle media connection 114. This allows the channel 116', located at the bottom left of the media distributor 113, to be cleaned. The other three channels 116, 116' are not cleaned, although the associated actuator modules could dispense during this time. The seal 115 seals the channels 116, 116' against other elements of the dosing head 9 when assembled.

In 19 Two pneumatic valves 7 are visible, arranged in the housing 110, each supplying four actuator modules 3 with compressed air in this example. The operation of the pneumatic valves 7 is controlled by a circuit board 122 as a control unit. The metering head 9 includes a compressed air tank 119 as a storage reservoir, which is implemented as part of the supply element 90.

The compressed air tank 119 supplies all pneumatic valves 7 of the metering head 9 with compressed air during operation. The compressed air tank 119 has several hose fittings 121 which are connected to hoses (not shown) during operation to supply compressed air to the compressed air tank 119 from outside the metering head 119. The metering head 9 also includes a collection area 120 for compressed air that has already flowed out of the metering valves 7. The collection area 120 is part of the supply element 90 and has several hose fittings 121' to convey the compressed air outside the metering head 9 via hoses (not shown).

The dosing head 9 has a retaining plate 117 with a plurality of recesses, in each of which an actuator module 3 can be inserted into a recess and, as in 20 shown, detachably arranged by means of screws on the mounting plate 117. The respective actuator module 3 protrudes with its upper part through the media distributor 113 and is arranged in a 3D printed part 123 of the dosing head 9 ( 19 ). In 19 It is further evident that the supply element 90 includes a heating element 118 which is connected to the circuit board 122 in a manner not shown in detail, in order to heat the mounting plate 117 and thus (indirectly) the fluidic units 30 of the actuator modules 3.

In 22 and 23 It is shown that the dosing head 9 in this example has nine pneumatic modules 124, each comprising two pneumatic valves 7. The two pneumatic valves 7 are arranged here in an optional housing. The pneumatic valves 7 are partially arranged in a 3D-printed part 123, which is shown here transparently and which can be connected by screws to another 3D-printed part 123' of the supply element 90. The 3D-printed part 123 of the pneumatic module 124 includes channels 125, 125' which, in the assembled state of the dosing head, are connected to the compressed air tank 119 and to the compressed air collection area 120 in the dosing head, respectively. The 3D printed part 123 further includes channels arranged such that the compressed air from a working port 126 of the respective pneumatic valve 7 is directed to the second actuator chambers of four coupled actuator modules (not shown), with the compressed air of the other working port 126' being directed to the respective other actuator chambers of the four actuator modules.

Finally, it should be noted once again that the pneumatic actuators, actuator modules, metering valves, and metering heads described in detail above are merely exemplary embodiments which can be modified in various ways by those skilled in the art without departing from the scope of the invention. In particular, the described pneumatic actuator is not limited to jet valves but can also be used in other metering valves with a movable plunger. Furthermore, the use of the indefinite articles "a" or "an" does not preclude the possibility that the relevant features may be present multiple times.

Reference symbol list

1

pneumatic actuator

2

Pestle

3

Actuator module

4

Metering valve

5

membrane

6

Module carrier

7

pneumatic valve

8

Media supply

9

dosing head

9'

Actuator module assembly

10

Cylinder/Hollow Cylinder

10'

Wall

10''

interior

11

Stop/lift stop

12

Hollow cylinder

12'

Wall

12''

interior

13

Sealing element

14

Sealing element

15

Actuator chamber

16

Actuator chamber

17

Housing

20,

20' piston

21,

21' Side/Area Piston

22

pushrod

22'

Outer surface of pushrod

23

tread

24

coating

25

Pestle tip

26

Metering material seal

27

Drainage opening

30

Fluidic unit

31

Guide element

32

sliding surface

33

Interior wall guide element

34,

35 Channel

36

Nozzle chamber

37

nozzle

37'

nozzle insert

38

cylindrical part

39

Media connection

50, 51

Membrane

52

stop

53

recess

70, 71

Work connection

90

Supply element

91, 91', 92, 92'

channel

93, 93'

plate

94

additively manufactured part

95

Drilling

96, 96'

channel

97

Mounting plate

98

Connection

99

Housing

100

Roller valve

101

Housing

102-105

channel

106, 107

Work connection

110

Housing

111, 111'

Connection

113

Media distribution list

114

Media connection

115

seal

116, 116'

channel

117

Mounting plate

118

heating element

119

compressed air tank

120

Collection area

121, 121'

hose fitting

122

circuit board

123, 123'

3D printed part

124

Pneumatic module

125, 125'

channel

126, 126'

Work connection

B, B', B''

Area

D

diameter

DL

Pressure medium/compressed air

DS

Dosage substance

DT

Sealing position

EP, EP'

Final position

R

Direction

S

position

SP

gap

Claims (18)

Pneumatic actuator (1) for a metering valve (4) for metering metering substance (DS), which pneumatic actuator (1) has a plunger (2) for dispensing metering substance (DS) from the metering valve (4), wherein the plunger (2) is formed in one piece and comprises at its end a piston (20) which is mounted in a cylinder (10) of the pneumatic actuator (1) without a seal relative to the cylinder (10), and wherein at least one side (21, 21') of the piston (20) can be pressurized with a pressure medium (DL) to move the plunger (2) in a direction (R). pneumatic actuator according to Claim 1 , wherein two opposite sides (21, 21') of the piston (20) can be acted upon with a pressure medium (DL) to move the plunger (2) in different directions (R). pneumatic actuator according to Claim 1 or 2 , wherein the pneumatic actuator (1) has a stop (11) for the piston (20), which stop (11) forms a sealing element (13) wherein the sealing element (13) is configured to form a tight connection between the piston (20) and a wall (10') of the cylinder (10) in a first end position (EP) of the plunger (2), and/or wherein the pneumatic actuator (1) has an elastic sealing element (14) configured to form a tight connection between the piston (20) and a wall (10') of the cylinder (10) in a second end position (EP') of the plunger (2) which differs from a first end position (EP). Pneumatic actuator (1) for a metering valve (4) for metering a metering substance (DS), in particular according to one of the preceding claims, wherein the pneumatic actuator (1) has a plunger (2) for dispensing metering substance (DS) from the metering valve (4), wherein the plunger (2) comprises at its end a piston (20) which is mounted in a cylinder (10) of the pneumatic actuator (1), wherein at least one side (21, 21') of the piston (20) can be pressurized with a pressure medium (DL) to move the plunger (2) in a direction (R), and wherein the pneumatic actuator (1) has a diaphragm (5) which rests on the piston (20), wherein the diaphragm (5) is movably mounted in the cylinder (10) such that in a sealing position (DT) of the diaphragm (5) a tight connection to a wall (10') of the cylinder (10) is formed, wherein in another position (S) the pressure medium (DL) can flow from one side (50) of the membrane (5) to the other side (51). Pneumatic actuator according to one of the preceding claims, wherein the weight of the plunger (2) is less than 2 grams, preferably less than 1.5 grams, more preferably less than 1 gram, particularly preferably less than 0.5 grams, and/or wherein the weight of the plunger (2) is at least 0.1 grams, and/or wherein the material of the plunger (2) is selected from hard metal, ceramic, polyetheretherketone, polyetheretherketone with carbon fibers, titanium and/or carbon fiber reinforced plastic and/or mixtures thereof, and/or wherein the diameter (D) of the piston (20) is less than 6 mm, preferably less than 5 mm, and/or wherein the diameter (D) of the piston (20) is greater than 3 mm, preferably greater than 4 mm, in particular 4.62 mm. Pneumatic actuator according to one of the preceding claims, wherein a pushrod (22) of the plunger (2) has a coating (24) at least in the region of a metering seal (26) which reduces the coefficient of friction of the pushrod (22), and/or wherein a ratio of a circumference of the piston (20) and a circumference of a pushrod (22) of the plunger (2) is at least 3 to 1 or greater, preferably 4 to 1, and/or wherein the piston (20) has a square or oval cross-section, and/or wherein the pneumatic actuator (1) has a stop (11) for the piston (20) to set a specific actuator stroke and/or a specific speed of the plunger (2). Pneumatic actuator according to one of the preceding claims, wherein the pneumatic actuator (1) has a plunger guide for guiding the plunger (2) which is realized by means of the piston (20, 20') and/or the cylinder (10), wherein preferably the plunger (2) has two pistons (20, 20') spaced apart from each other at its end. Pneumatic actuator (1) for a metering valve (4) for metering metering substance (DS), in particular according to one of the preceding claims, wherein the pneumatic actuator (1) has a plunger (2) for dispensing metering substance (DS) from the metering valve (4), wherein the plunger (2) comprises at its end a piston (20) which is mounted in a cylinder (10) of the pneumatic actuator (1), wherein at least one side (21, 21') of the piston (20) can be pressurized with a pressure medium (DL) to move the plunger (2) in a direction (R), and wherein at least one pneumatic roller valve (100) is associated with the pneumatic actuator to supply the pneumatic actuator (1) with pressure medium (DL). Pneumatic actuator according to one of the preceding claims, wherein the pneumatic actuator (1) has a pneumatic pre-control. Actuator module (3) with a pneumatic actuator (1) according to one of the preceding claims, wherein the actuator module (3) has a fluidic unit (30) which is connected to the pneumatic actuator (1) and which is configured to provide metering medium (DS) in the region of a plunger tip (25) of the plunger (2), and/or wherein a fluidic unit (30) of the actuator module has two channels (34, 35) which open into a nozzle chamber (36) of the fluidic unit (30) and which can be separately supplied with medium (DS). Actuator module after Claim 10 , wherein the fluidic unit (30) has a metering seal (26) which forms a plunger guide for guiding the plunger (2), wherein the actuator module (3) for guiding the plunger (2) has the plunger guide of the metering seal (26) and a further plunger guide which is realized by means of the piston (20, 20') and/or the cylinder (10). Actuator module after Claim 10 or 11 , wherein the actuator module (3) has a guide element (31) which forms a sliding surface (32) for a pushrod (22) of the plunger (2), wherein preferably the guide element (31) is located in the pneumatic matikaktor (1) is pressed in, and/or wherein a guide element (31) of the actuator module (3) has at least in the area of a sliding surface (32) a material selected from hard metal and/or sapphire and/or ruby and/or ceramic. Actuator module according to one of the Claims 10 until 12 , wherein the actuator module (3) can be coupled to a module carrier (6) which has at least one pneumatic valve (7) and a media supply (8) to form a metering valve (4), and/or wherein the actuator module (3) has a pneumatic pilot control. Dosing head (9) with at least one actuator module (3) after one of the Claims 10 until 13 , wherein the actuator module (3) is arranged on the metering head (9) and wherein the metering head (9) has a supply element (90) with channels (91, 91', 92, 92', 96, 96') to supply the actuator module (3) with metering fluid (DS) and with pressure medium (DL), and/or wherein the metering head (9) has a plurality of actuator modules (3) according to one of the Claims 10 until 13 comprising, wherein the actuator modules (3) are arranged on the dosing head (9) and wherein the dosing head (9) has a supply element (90) with channels (91, 91', 92, 92', 96, 96') to supply the actuator modules (3) separately with dosing material (DS) and with pressure medium (DL). Dosing head after Claim 14 , wherein the metering head (9) has at least one pneumatic valve (7) which is assigned to two or more actuator modules (3), and/or wherein each actuator module (3) has a pneumatic valve (7) assigned to it, and/or wherein the metering head (9) has at least one pneumatic roller valve (100) to supply at least one actuator module (3) of the metering head (9) with pressure medium (DL), and/or wherein at least one actuator module (3) or several actuator modules (3) have pneumatic pilot control. Dosing head after one of the Claims 14 or 15 , wherein the supply element (90) has several plates (93, 93') which each comprise parts of channels (91, 91', 92, 92', 96, 96') and wherein the plates (93, 93') are arranged such that channels (91, 91', 92, 92', 96, 96') are formed for metering material (DS) and/or pressure medium (DL) for supplying the actuator modules (3), and/or wherein the supply element (90) is additively manufactured or at least has an additively manufactured part (94) with channels (91, 92, 92', 96, 96') for supplying the actuator modules (3). Metering valve (4) with a pneumatic actuator (1) according to one of the Claims 1 until 9 , preferably with an actuator module (3) according to one of the Claims 10 until 13 , and with at least one pneumatic valve (7) and a media supply (8). Method for controlling a pneumatic actuator (1) for a metering valve (4) for metering a metering substance (DS), wherein the pneumatic actuator (1) has a plunger (2) for dispensing metering substance (DS) from the metering valve (4), wherein the plunger (2) is formed in one piece and comprises at its end a piston (20) which is mounted in a cylinder (10) of the pneumatic actuator (1) without a seal relative to the cylinder (10), and wherein at least one side (21, 21') of the piston (20) is acted upon with a pressure medium (DL) in order to move the plunger (2) in a direction (R).