DE102018008846A1 - Solenoid valve, control electronics for a solenoid valve and method for controlling a solenoid valve - Google Patents

Abstract

Solenoid valve in particular for an electropneumatic drive, which is used in particular in a process engineering system, comprising an in particular ring-shaped magnet coil, a magnetic yoke receiving a magnet coil made of a magnetizable material, on the inside of which an armature is movably arranged and the outside of which at least partially surrounds the magnet coil , a magnetic field sensor, in particular a Hall sensor, for detecting, in particular measuring, the magnetic flux density, a profile jump, such as a profile depression, for example a groove, being formed on the outside of the magnetic yoke, the magnetic field sensor being arranged in the region of the profile jump.

Description

The present invention relates to a solenoid valve, in particular for an electropneumatic drive, which is used in particular in a process plant, for example a chemical or petrochemical plant, a food processing plant, a nuclear power plant or other process plant. The pneumatic actuator can be used, for example, to actuate a control valve, such as a control valve. Furthermore, the invention relates to control electronics for controlling a solenoid valve and a method for controlling the solenoid valve.

Such a solenoid valve can be provided with a sensor for determining an armature position in such a solenoid valve. Furthermore, the invention relates to a method for controlling the solenoid valve and a positioner, in particular an electropneumatic positioner, which can operate according to the mode of operation of the control method according to the invention and / or comprises a solenoid valve according to the invention. Such a positioner can be coupled to a pneumatic drive that actuates a field device of the process engineering system, such as a control valve or an emergency shutdown valve.

Solenoid valves are usually operated by an electromagnet. The generic solenoid valve has, in particular, an annular magnet coil, the inductances of which generate a magnetic field that preferably allows an armature of the solenoid valve to be displaced in a translatory actuating movement. It is known that the armature of the solenoid valve moves into a retracted position when energized, while in the absence of a magnetic field the armature is moved into an extended position. Depending on the position of the armature, the solenoid valve opens or closes. The coil is usually wound around a central section or magnetic core of a so-called magnetic yoke of the solenoid valve. The movable armature is usually ferromagnetic and is attracted by the magnetic field generated by the coil and amplified by the magnetic core. The magnetic field formed between the armature and the core exerts a force, in particular from the air gap formed between the armature and the magnetic core depends. The smaller the distance between the magnetic core and the armature, the stronger the magnetic force. The solenoid valve is usually provided with a valve seat which cooperates with a valve member coupled to the armature in such a way that it opens and or at least partially seals channels or paths in the valve housing in one or more positions of the valve member.

A solenoid valve with a magnetic sensor for measuring a magnetic flux and thus for calculating and regulating the forces acting on the armature is off DE 10 2015 116 464 A1 known. The solenoid valve has a magnetic field sensor, in particular a Hall sensor, for measuring the magnetic flux density, which is arranged between the armature and the magnetic core in an air gap. The air gap is formed in the interior of the magnetic yoke, radially on the inside with respect to the ring coil of the solenoid valve, which is received in the magnetic yoke. A hollow cylindrical web is used to partially cover the air gap and forms part of an outer section of the magnetic return path of the solenoid valve. Due to the magnetizable web, part of the magnetic field is conducted through the air gap, the magnetic flux density of which is similar to the flux density of an air gap between the core and the armature. By measuring the magnetic field, conclusions can be drawn about the forces acting on the armature.

The solenoid valve described above requires a special and complex housing or yoke structure, in particular around the web, which engages in an annular cylindrical cavity in order to form an adequate measuring air gap.

For actuation of the above-described or other generic solenoid valves, a single, in particular maximum, electrical power is required for energizing the coil. The magnetic armature is set into motion after overcoming static friction and is kept in the switched state when current is present (peak current, pull-in current). This maximum power is always requested, although it is not necessary to hold the magnet armature.

The object of the invention is to overcome the disadvantages of the prior art, in particular to provide a solenoid valve which is operated in an energy-efficient manner and in particular reliably detects a malposition of the solenoid valve without having to change the basic structure of the solenoid valve.

This object is achieved by a solenoid valve according to claim 1. Advantageous further developments result from the subclaims.

According to a first aspect of the invention, a solenoid valve is proposed in particular for an electropneumatic drive, which is used in particular in a process engineering system.

The solenoid valve according to the invention has in particular the function of a direct acting Solenoid valve. The solenoid valve is operated by an electromagnet. By applying an electrical voltage, a coil is energized and generates a magnetic field that attracts an armature attached to a valve stem, so that the valve opens or closes. The valve seat is in particular designed such that it switches and seals corresponding channels in the valve housing in both end positions.

The solenoid valve according to the invention comprises an in particular ring-shaped solenoid coil and a magnetic yoke receiving a solenoid coil, on the inside of which an armature is movably arranged, in particular mounted, and the outside of which at least partially surrounds the solenoid coil and / or which at least partially encloses the solenoid coil. The inference limits an in particular cylindrical cavity in which an armature, for example like a piston, can be moved back and forth along a linear adjusting movement. The conclusion can also be called a magnetic yoke. The coil can also be referred to as a winding or inductance. The magnetic valve according to the invention also has a magnetic field sensor, in particular a Hall sensor, a Hall switch sensor or a reed contact, for detecting, in particular measuring, the magnetic flux density. According to the invention, a profile jump, such as a profile recess ( 20th ), for example a groove, wherein the magnetic field sensor is arranged in the area of the profile jump. The profile jump forms in particular a weakening of the magnetizable material of the magnetic yoke, as a result of which the magnetic resistance of the magnetic circuit in the magnetic yoke is increased. In the specific energized state of the coil, field lines in the area of the profile jump can emerge from the inference. With a specific excitation current applied to the magnetic coil, this makes it possible, based on the magnetic field sensor placed in the area of the profile jump, to infer the dimension of the so-called working air gap between the armature and the magnetic yoke, in particular its central core section, which working air gap is in the course of the Operation of the solenoid valve enlarged and reduced. The magnetic field sensor detects the magnetic flux in the area of the profile jump, in particular in the profile recess, in order in particular to determine the position of the armature.

If the armature drops, for example, the total magnetic resistance increases and, with the excitation current remaining the same, the magnetic field strength in the recess decreases, which is detected by the sensor. Conclusions about the anchor position can be drawn from this. The sensor thus detects whether the armature is attracted or not when the voltage is applied. In the recess, the sensor thus detects the strength of the stray field through the slot air gap or changes the predefined initial state when a switching threshold is undershot / exceeded. In this way, the sensor can differentiate between the “anchor pulled up” and “anchor dropped” states and output a corresponding electrical signal that is recorded by a control unit.

In a preferred embodiment of the invention, the profile jump is designed as a profile recess, such as a groove. The profile recess is preferably formed in the otherwise otherwise uniform outside of the body of the magnetic yoke. For example, the outside of the magnetic yoke is an outside face, which lies flat and / or perpendicular to the direction of displacement of the armature, or a rotationally shaped, in particular cylindrical, surrounding outside, which in particular preferably completely surrounds the magnet coil. The groove preferably has a radial or axial profile depth of less than 20 or 10 mm, in particular a profile depth of more than 50%, 60%, 70%, 80% of the wall thickness of the yoke towards the coil.

An air gap is preferably formed between the magnetic field sensor arranged in the profile recess and a wall of the profile recess. The wall of the profile recess is defined in particular by wall regions, for example side walls or a bottom section of an in particular blind hole-shaped and / or circumferential recess on the outside of the magnetic yoke. In particular or alternatively, the profile recess is made in the form of a blind hole and / or circumferentially in the magnetic yoke, and / or a measuring point of the magnetic field sensor is arranged within the profile recess. The profile recess preferably has a depth taken from an outside, such as an end face or a cylindrical circumferential side, of the magnetic yoke, a dimension which is selected such that the structural extension of the magnetic field sensor and / or the optimal measuring point defined by the magnetic field sensor is completely within the profile recess is arranged. The magnetic field sensor is preferably arranged in such a way that it, in particular its structural dimension, projects into the profile recess.

The magnetic field sensor is preferably designed to detect whether a predetermined magnetic field strength, such as a solenoid valve switching threshold (armature pulled in / armature dropped out), is exceeded, in order, depending on the situation, to indicate a corresponding status signal, such as an overshoot signal or an undershoot signal can deliver control electronics that preferably cause energization of the solenoid. The control electronics can be, for example, a higher-level central control or a solenoid valve-specific micro-computing unit that is coupled directly to the magnetic field sensor. The control electronics can form part of the structure of the solenoid valve. The control electronics can comprise a printed circuit board to which electronic components and / or the magnetic field sensor is fastened, wherein in particular the longitudinal extension of the printed circuit board can be selected such that it can protrude beyond the outside of the magnetic yoke in the profile recess.

In a development of the invention, the magnetic field sensor is designed to determine the position of the armature, in particular along its translational travel path, using a magnetic flux in the area of the profile jump. The magnetic field sensor can act as a position sensor that can communicate with a position control, such as a positioner.

In a preferred embodiment of the invention, the solenoid valve according to the invention has control electronics which is designed in particular in accordance with the control electronics according to the invention explained below and / or is designed to deliver a pull-in current or a holding current to the solenoid coil as excitation current, the pull-in current in particular being set in this way that the armature moves into the particularly retracted end position. The control electronics are preferably designed to deliver a holding current to the magnetic coil as an excitation current as soon as the armature is in a particularly retracted end position, the holding current in particular being set such that it is lower than the pull-in current and / or the armature in particular retracted end position holds.

The inference is made of a magnetizable material, preferably a ferritic material. In one example, the yoke has a circumferential receiving body for receiving the magnetic coil and a core which is substantially axially diametrically opposite the armature and which is formed along an axis of symmetry of the yoke or a translational movement axis of the armature and / or on which the armature is located in particular in one of the End positions of the solenoid valve supports or strikes.

According to a preferred embodiment, the armature is connected to a core of the yoke via a spring element, the working air gap being formed between the armature and the core. The size of the working air gap varies as the anchor moves in and out of the room. When the magnetic field is not present, the armature is forced into an extended position by the spring element. The armature is in a retracted position when the magnetic field is applied. In one example, the armature can be moved translationally along a longitudinal direction of the armature and / or along an axis of symmetry of the solenoid valve from the retracted position to the extended position. In one example, the armature actuates a valve member (closure member) of a control valve.

According to a further preferred embodiment, the solenoid valve has control electronics which are designed to draw a pull-in current or a holding current as excitation current to the solenoid coil ( 14 ), whereby in particular the pull-in current is set such that the armature ( 12th ) moved into the retracted end position in particular. The control electronics can preferably be designed to transmit a holding current as an excitation current to the magnetic coil ( 14 ) to be emitted as soon as the armature is in a particularly retracted end position, the holding current in particular being set such that it is lower than the pull-in current and / or holding the armature in the particularly retracted end position.

The control electronics regulate the excitation current in such a way that the respectively required current is present on the coil to attract and to hold the armature securely. This can reduce the current consumption of the solenoid valve. Since a magnetic air gap has decreased in a first position after switching the valve and thereby also the magnetic resistance of the magnetic circuit, a reduced current or a reduced magnetic field is sufficient to hold the armature in the retracted position. The current is regulated to a lower holding current after a specified time, which reduces the power consumption. However, there is now a risk that due to external force (e.g. impulse / acceleration in the form of a blow to the solenoid valve or due to pipeline vibrations) the armature can drop due to insufficient magnetic attraction forces in the holding state and an unintentional position of the valve seat is achieved, which is achieved by the solenoid valve described above is detected. After detecting an anchor drop, it is possible to tighten the anchor again with a high output in order to counteract the undesired effect of the anchor drop.

According to a further preferred embodiment, the recess is dimensioned such that the back yoke, preferably iron back yoke, is in a magnetic saturation state in the region of the recess when the excitation current is applied, preferably just just exceeds the limit of the saturation state when the anchor is held in the retracted position. The saturation state of the magnetic yoke describes the state in which some of the magnetic field lines emerge from the material of the yoke. The field strength in the area of the recess with magnetic saturation is for example in the range of 6-15 mT, in particular 10-15mT, preferably 12-14 mT.

According to one embodiment, the magnetic field sensor is designed to detect the state of saturation in the recess and to output a first signal that the armature is in the drawn-in position or in the held state in the retracted position. According to one embodiment, the sensor is also designed to detect that the recess is not in the saturation state and to output a second signal that the armature drops in the direction of the extended position, in particular as a result of a malfunction or an incorrect operation of the solenoid valve.

Due to the lower holding current compared to the attraction current, the armature can drop out of the retracted position due to insufficient magnetic attraction forces. A drop can be triggered, for example, by external forces (e.g. shock, pipe vibrations). If the armature moves away from the core with a constant holding current, i.e. falls, the air gap between the core and the armature increases. An increase in the air gap causes an increase in the total resistance of the magnetic circuit. This means that the area of the recess is less flooded. The magnetic material of the inference is now no longer saturated and can lead the required flux completely. The field line strength is thus reduced, for example to a range of 1-5 mT, in particular 1-3 mT, in the air region of the recess. The anchor status "attracted" or "fallen off" can also be indicated by a display element (e.g. LED). Furthermore, this signal can also be transmitted to the control room in order to check the cause of the unwanted anchor drop on site if necessary.

Furthermore, the invention relates to an electronic control for actuating a solenoid valve, in particular according to the above-mentioned, according to the invention, in particular for an electropneumatic drive, which is used in particular in a process engineering system. The solenoid valve can be brought into an on-switching state and an off-switching state. The electronic control according to the invention comprises a supply output for applying an excitation current to a coil of the solenoid valve in order to move the solenoid valve from the off-switching state to the on-switching state. In order to apply a supply voltage to the electronic control, it can also have an electrical supply input, which in particular also serves to supply the electronic components of the electronic control with electrical energy. Furthermore, the electronic control according to the invention has a switching regulator for setting the excitation current on the coil, the switching regulator being designed to apply a pull-in current to the coil of the solenoid valve when it is switched to the on state and to apply a holding current to subsequently hold the on state applied to the coil, which is lower than the pull-in current. The control variable of the switching regulator can be, for example, the magnetic flux density, the magnetic resistance of the magnetic circuit, etc., which parameters can be determined and used in particular by the magnetic field sensor.

In the preferred embodiment of the invention, the electronic control can have a sensor, in particular a magnetic field sensor, for detecting whether the solenoid valve has reached a specific switching state, such as the on-switching state, the sensor being electrical from an input voltage applied to the electronic control is supplied and / or the sensor is arranged in a recess, such as a groove, a metal body, such as a yoke, of the magnetic yoke, and / or comprise a circuit board for power electronics of the switching regulator, the magnetic sensor on the circuit board in a recess, such as a groove, a metal body, such as a yoke, of the magnetic yoke is arranged, wherein in particular the sensor is also applied to the circuit board. The groove is preferably circumferential.

According to a further embodiment, the control electronics have a resistor, preferably a shunt resistor, a comparator, and a transistor, preferably MOSFET, in order to regulate the excitation current in the coil to the holding current. The resistor connected in series with the coil can generate a voltage drop proportional to the excitation current. When the pull-in current is applied as an excitation current, the voltage drop across the resistor reaches a threshold value, the threshold value being determinable in the comparator. The comparator interrupts the current flow in the coil via the transistor towards ground when this threshold value is reached. A freewheeling diode connected to the coil dissipates the current in the coil when the comparator interrupts the current flow. The transistor closes automatically after a predetermined time, preferably in the range of a few microseconds, so that the current flow from the coil towards the ground increases again and is interrupted again by the comparator when the threshold value is reached. The threshold is in that Comparator for regulating from a pull-in current to a holding current to a lower threshold value, so that the excitation current in the coil can be regulated to the desired holding current.

The control electronics can also be referred to as power electronics. The control unit applies a pull-in current to the coil until the armature changes its state and the sensor outputs the "armature energized" status signal. The pull-in current can also be called the peak current. If the armature is attracted, the control unit lowers the current after a certain time and applies the holding current to the coil. The holding current can also be a hold current. By monitoring the armature position and regulating the coil current to a low level, a very large amount of energy can be saved without endangering regular valve operation.

According to a further embodiment, the control electronics are designed such that they receive the second signal from the magnetic field sensor when the armature has dropped out unintentionally, the control unit then changing the threshold value in the comparator in such a way that the coil can be excited with the attraction current and the anchor can be pulled back into the retracted position.

At the same time, the electronic connection of the control electronics can also take place in such a way that the sensor - as already described above - is evaluated. If the magnetic field sensor outputs the second signal "armature dropped off", the electronics increase the threshold voltage of the comparator to the pull-in current and thus ensure that the armature changes to the "armature pulled up" state.

According to a further embodiment, the control electronics are designed to signal that the armature is in a blocked position when the applied pull-in current is received and the second signal from the sensor is received.

For example, the complete armature stroke cannot be carried out due to a foreign body within the valve and flow area or due to seal or material failure, in particular friction, blocking or jamming. Furthermore, a continuous evaluation of the armature stroke can be carried out by means of the detection of the attraction current described above and the evaluation of the signal from the sensor. This makes it possible to detect an intermediate position and to obtain further conclusions about the position of the valve stem. For example, a complete and safe valve lift can be prevented by a fault, so that either opening or closing of the valve plug on the valve seat is prevented. This would not guarantee the corresponding safety position, particularly in safety-relevant applications, and a critical state would occur. By recording the various anchor positions, the exact valve position can be recorded and, if necessary, reported back to the user / operator as a malfunction.

According to one embodiment, the sensor is a magnetic field sensor, preferably a Hall sensor or a Hall switch sensor or a reed contact.

To detect the drop of the anchor, i.e. the detection of the field strength in the slightly saturated state to the non-saturated state can be used, for example, a Hall Switch Sensor that has a defined switching threshold between the states "armature attracted" and "armature dropped", which is preferably between 13.6 and 1.7 mT , preferably in the middle is 7.6 mT.

According to one embodiment, a control circuit board of the control electronics receives the magnetic field sensor directly. The magnetic field sensor is arranged in such a way that it projects into the recess. This makes it possible to place the sensor directly on the outside of the solenoid valve and directly on a control circuit board of the control electronics without additional connecting elements. The sensor is supplied, for example, like the control unit via the input voltage. Complicated housing structures and cable entries inside the solenoid valve can be avoided.

Finally, the invention relates to a method for controlling a solenoid valve according to the invention, described above, for example for an electropneumatic drive, which is used in particular in a process engineering system. In the method, the solenoid valve can either be brought into an on-switching state or into an off-switching state. A pulling current is applied to a coil of the solenoid valve to move the solenoid valve from the off-switching state to the on-switching state. In the on-state, the pull-in current remains applied to the coil for a pull-in time, and after the pull-in time, a holding current is applied to the coil that is lower than the pull-in current.

In a preferred embodiment of the invention, during the application of the holding current to the coil by means of a sensor, preferably a magnetic field sensor, the on-state of the solenoid valve is monitored whether the solenoid valve leaves the on-state and, if the solenoid valve leaves the on-state , the pull-in current is applied to the coil, whereby in particular, leaving the specific switching state of the solenoid valve by detecting an increase in a magnetic resistance of the magnetic metal circuit in the area of the magnetic yoke of the solenoid valve, in particular in the area of a weakening, such as a depression, for example a groove, in a metal body of the magnetic yoke.

In a development of the method according to the invention, it can be provided that the holding current is only applied when a specific switching state of the solenoid valve, preferably the on-switching state, is reached, in particular when the specific switching state is reached by means of a sensor, in particular a magnetic field sensor which, in particular, can detect the strength of a stray field on the outside of a metal body of a yoke of the solenoid valve, and / or when the holding current is present, the pull-in current is reapplied to the coil when a deviation of the solenoid valve, which is determined in particular by the specific switching state , preferably from the on-switching state, in particular from a sensor such as a magnetic field sensor.

According to a further aspect of the invention, the method according to the invention for regulating a solenoid valve is proposed, which has the following steps: actuation of the solenoid valve with a pulling current in order to move an armature into a retracted position. The solenoid valve is actuated by a holding current to hold the armature in the retracted position, the holding current being lower than the pull-in current. The current is set depending on how the armature positions itself with respect to a core section of the magnetic yoke and / or a magnetic field sensor determines the position of the armature.

According to a further embodiment, the method further comprises the following steps: detecting by a sensor, preferably a magnetic field sensor, that the armature is in the drawn-in state or in the held state in the retracted position, and then outputting a first signal.

According to a further embodiment, the method further comprises the following steps: detecting a drop in the armature in the direction of an extended position by the sensor, and then outputting a second signal.

According to a further embodiment, the method also has the following steps: application of the pull-in current by the control unit, so that the coil can be excited with the pull-in current and the armature is pulled back into the retracted position. Operate the solenoid valve with the holding current to hold the armature in the first position.

According to a further embodiment, the method also has the following steps: detection by the control unit whether the attraction current and the second signal are present, and then signal that the armature is in a blocked position.

In a further example, the solenoid valve can also function as a seismograph by considering the armature-spring element unit as a spring-mass system, as well as the sensor, preferably a Hall sensor for detecting the vibrations, and the control unit for processing / converting the signal and is further used for signal evaluation.

• 1a eine schematische Querschnittsansichten eines Magnetventils gemäß einer Ausführungsform;
• 1b eine schematische Querschnittsansichten eines Magnetventils gemäß einer weiteren Ausführungsform; und
• 2a,b schematische Ansichten zum Verlauf der magnetischen Feldlinien im magnetischen Rückschluss mit Profilsprung gemäß einer Ausführungsform.

Further properties, features and advantages of the invention will become clear from the description of preferred embodiments of the invention with reference to the accompanying exemplary drawings, in which:

• 1a a schematic cross-sectional views of a solenoid valve according to an embodiment;
• 1b a schematic cross-sectional views of a solenoid valve according to a further embodiment; and
• 2a, b schematic views of the course of the magnetic field lines in the magnetic yoke with profile jump according to one embodiment.

1a-b show a solenoid valve 10th , comprising a magnetic yoke 14 , which can consist in particular of an iron body, which has a cup shape, in the middle of which a cylindrical guide is formed, in which an anchor 12th is arranged movably. The magnetic inference 14 has a substantially flat face 9 and a cylindrical circumferential side. ( 21st Kitchen sink)

In a central core section 16 of the iron body is a recess 17th trained in a compression spring 19th is arranged. The compression spring 19th reaches into one in the anchor 12th trained recess, and is thus stably mounted in radial directions. Compression spring 19th forces the anchor 12th in an extended end position, which in the 1a and 1b is not shown.

The magnetic inference 14 comprises an in particular annular cavity, in which a radially open winding body 25th is arranged, which receives a magnetic coil. The solenoid extends longitudinally in the axial direction much of the core section 16 and overlaps the anchor 12th over its entire axial working amplitude.

The outside of the winding body 21st limited at least partially (also an inside of the inference 14 ) the guide cylinder 23 in which the anchor 12th is retractable and extendable.

Between the anchor 12th and the core section 16 of magnetic inference 14 is a working air gap 25th educated. When an excitation current is provided on the solenoid 18th magnetic forces occur that cause the anchor 12th from its one end position into which the compression spring 19th the anchor 12th forces to be pulled into a retracted end position, which in the 1a and b is shown.

The solenoid valve according to the invention 10th has a pneumatic input 31 and a pneumatic outlet 33 which by a valve member 35 can be opened and closed. In the in the 1a and 1b The end position shown is a pneumatic connection between the channels 31 , 35 Cut. The end positions are determined by the opposite valve seat stops. The valve member 35 is fixed to the anchor 12th connected, in particular made from a piece of magnetizable material.

One in the 1a and 1b Control electronics, not shown, energize the coil 18th , whereby the pneumatic input / output ( 31 , 33 ) can be provided. The control electronics, not shown, can be part of a pneumatic positioner, which is part of a pneumatic drive of a process engineering system.

On the outside, namely on the front 9 , the body's magnetic inference 14 is a profile jump in the form of a groove 20th trained who according to 1a concentric to the longitudinal axis A the translational movement of the anchor 12th extends. The groove 20th is trained all round.

According to the execution 1b can the circumferential groove 20th also on the circumferential side 21st of magnetic inference 14 be trained. The groove forms in both versions 20th a weakening of the magnetic body of the inference 14 . So that is the magnetic resistance within the magnetic yoke 14 elevated.

A magnetic field sensor 22 is in the groove 20th arranged. The sensor 22 detects a magnetic flux in the groove 20th to a position of the anchor 12th to determine. In one example is the groove 20th a recess with a rectangular cross section 2nd opposite side walls and a bottom section. As in the 1a and 1b there is an air gap between the sensor 20th and one of the side walls and the bottom portion. Further recesses such as an arcuate recess are also conceivable.

It is in the 1a, b shown that the anchor 12th with a core section 16 the conclusion 14 via the compression spring 19th connected, being between the anchor 12th and the core section 16 the working air gap 25th is formed. The conclusion 14 is exemplary as a the coil 18th and the anchor 12th encased casing. The core section 16 is preferably an integral part of the inference 14 formed and along an axis of symmetry A of the solenoid valve 10th arranged. The core section 16 is as one towards the anchor 12th protruding section of inference 14 educated. One end of the anchor 12th and the face of the core 16 are arranged opposite each other and along the axis of symmetry of the solenoid valve 10th aligned. The size of the working air gap 25th varies due to the partial retraction and extension of the anchor 12th in and out of by inference 14 formed space. The anchor 12th is when the magnetic field is not applied by the spring element 19th pressed into the extended position. The anchor 12th is in a retracted position when the magnetic field is applied.

In one example is the anchor 12th translationally along a longitudinal direction of the armature and / or along an axis of symmetry of the solenoid valve 10th movable from the retracted position to the extended position. In an example shown here, the armature actuates 12th the valve member 35 (Closure organ). The closure element, which is directly connected to the magnetic armature, is pulled up and closes the upper seat of the valve (here 3/2 way valve as an example). When the excitation current is switched off, there is no magnetic field and the spring element 19th presses the anchor 12th back to its starting position, eg to the extended position and the locking device 35 closes the lower seat.

In a preferred embodiment, the solenoid valve 10th control electronics. The control electronics are designed such that a pull-in current or a holding current is supplied to the coil as an excitation current 14 to deliver. The attraction current is set around the armature 12th to move into the retracted position. The holding current after the anchor 12th located in the retracted position is set to the anchor 12th to keep in the retracted position. The holding current is lower than the pull-in current. The control electronics regulate the excitation current in such a way that to attract as well as securely holding the anchor 12th the current required at the coil 18th is present. This can reduce the power consumption of the solenoid valve 10th be reduced.

According to a further preferred embodiment, the groove 20th dimensioned so that the inference 22 , preferably iron yoke, in the area of the recess 20th is in a magnetic saturation state when the excitation current is applied, preferably just just exceeds the limit of the saturation state when the armature 12th is held in the retracted position, see 3a . The saturation state of the magnetic yoke 14 describes the state that part of the magnetic field lines from the material of the inference 14 emerge. In 3b is the working air gap 25th big, the anchor 12th has therefore dropped, the excitation current or the holding current still being present. The magnetic resistance of the magnetic circuit has increased due to the enlargement of the air gap. This will make the groove 20th , as in 3b shown, less flooded, ie the ferromagnetic inference 14 is no longer saturated and can lead the magnetic flux completely. Thus the field line portion goes in the air area of the groove 20th towards zero, or becomes significantly lower. In the image acquisition of the simulation in 3b the sensor detects just 1.7mT.

According to a further embodiment, the control electronics 24th , as in 2nd hinted at a resistance 26 , preferably shunt resistor, a comparator 28 , and a transistor 32 , preferably MOSFET, on to the excitation current in the coil 18th to regulate the holding current. The can to the coil 18th series resistor 26 generate a voltage drop proportional to the excitation current. When the pull-in current is applied as the excitation current, the voltage drop across the resistor reaches 26 a threshold value in the comparator 28 is definable. The comparator 28 interrupts the current flow in the coil 18th about the transistor 32 towards the mass when this threshold is reached. A freewheeling diode connected to the coil 30th carries the current in the coil 18th off when the comparator 28 interrupts the flow of electricity. The transistor 32 closes automatically after a set time, preferably in the range of a few microseconds, so that the current flows from the coil 18th in the direction of mass and again when the threshold value is reached by the comparator 28 is interrupted. The threshold is in the comparator 28 for regulation from a pull-in current to a holding current to a lower threshold value, so that the excitation current in the coil 18th can be regulated to the desired holding current.

The control electronics 24th can also be referred to as power electronics. The control electronics 24th follows a switching logic that the coil 18th impresses a pull-in current until the armature 12th its state changes and the sensor 22 the status signal to a control logic 36 (like a microcomputer) outputs "Anchor pulled". The pull-in current can also be called the peak current. Is the anchor 12th tightened, the control electronics lower 24th the current after a certain time and impresses the holding current on the coil. The holding current can also be a hold current. By monitoring the armature position and regulating the coil current to a low level, a very large amount of energy can be saved without endangering regular valve operation.

The principle of operation of peak and hold current is based on the switching regulator type "buck converter". One in line to the coil 34 switched shunt resistor 26 generates a voltage drop proportional to the excitation current. After applying a supply voltage, the excitation current increases in the coil 18th on, the voltage drop across the shunt resistor reaches 26 a certain upper limit, which is determined and detected via a comparator circuit. The comparator 28 interrupts via the transistor when this threshold value is reached 32 or the electronic switch (eg a MOSFET switch) the current flow through the coil 18th towards the crowd. Because the current through the coil 18th does not stop abruptly, it is targeted via a free-wheeling diode 30th continued. The control logic closes after a specified time of a few microseconds 36 the control electronics 24th the electrical switch again and until then via the freewheeling diode 30th flowing current in the coil 18th flows back towards the mass. As a result, the current rises until the voltage at the shunt resistor 26 the comparator threshold voltage is reached and the MOSFET interrupts the connection to ground again. This process is now repeated, causing the current in the coil 18th is kept on a rippled, constant current.

By changing the comparator threshold voltage during the operation of the valve 10th the level of the coil current or excitation current can be varied. The threshold voltage of the comparator 28 control electronics regulates lower 24th effectively a lower current in the coil 18th . Through clever wiring, it can be achieved that after the first energization of the circuit an attraction current (peak current) is regulated, which leads to the valve armature 12th safely changes to the "starter dressed" state. If this state is reached after a certain time, the control electronics will move 24th the current down to the holding current, thereby reducing the current from the coil 18th power consumed is reduced.

At the same time, the electronic connection of the control electronics 24th also take place in such a way that the sensor - as already described above 22 is evaluated. The sensor gives 22 the second signal "anchor dropped" to the control logic 36 off, the electronics increase the threshold voltage of the comparator 28 on the pull-in current and thus achieves that the armature 12th changes to the "anchor pulled" state.

According to a preferred embodiment, a control circuit board takes the control electronics 24th the magnetic field sensor 22 directly on. The magnetic field sensor 22 is arranged so that it fits into the groove 20th protrudes as in 1a shown schematically. This makes it possible for the sensor 22 directly on the outside of the solenoid valve 10th and without additional connecting elements directly on a control circuit board 40 the control electronics 24th to arrange. The sensor 22 becomes, for example, like the control electronics 24th supplied via the input voltage.

Complicated housing structures and cable entries inside the solenoid valve 10th can be avoided.

According to a further aspect of the invention, a method for regulating a solenoid valve 10th proposed, which has the following steps: actuation of the solenoid valve 10th with a pull current to an anchor 12th to move a retracted position. Actuation of the solenoid valve 10th with a holding current to the anchor 12th to keep in the retracted position, the holding current being lower than the attraction current.

According to a further embodiment, the method also has the following steps: Detection by a sensor, preferably a magnetic field sensor 22 that the anchor 12th is in a tightened state or in a held state in the retracted position and then outputting a first signal.

According to a further embodiment, the method further comprises the following steps: detecting a drop in the armature 12th towards an extended position by the sensor, and then outputting a second signal.

According to a further embodiment, the method also has the following steps: application of the pull-in current by the control electronics 24th so that the coil 18th is excitable with the attraction current and the armature 12th is pulled back into the retracted position. Actuation of the solenoid valve 10th with the holding current to the anchor 12th to keep in the first position.

According to a further embodiment, the method also has the following steps: detection by the control electronics 24th whether the attraction current and the second signal are present and then signal that the armature is in a blocked position.

In another example, the solenoid valve 10th also act as a seismograph in that the armature-spring element unit is regarded as a spring-mass system and the sensor, preferably a Hall sensor, is used to detect the vibrations, and the control unit is used for processing / converting the signal and further for signal evaluation.

The exemplary embodiments described above can be combined in different ways. In particular, aspects of the method can also be used for embodiments of the devices and use of the devices and vice versa.

In addition, it should be pointed out that "comprehensive" does not exclude other elements or steps and "one" or "one" does not exclude a large number. The features disclosed in the above description, the figures and the claims can be important both individually and in any combination for realizing the invention in the various configurations.

Reference symbol list

9

Face

10th

magnetic valve

12

anchor

14

Conclusion

16

Core section

17th

Recess

18th

Solenoid

19th

Compression spring

20th

Groove

21

Perimeter

22

Magnetic field sensor

23

Guide cylinder

25th

Bobbin

26

Shunt resistance

28

Comparator

30th

Free-wheeling diode

31

pneumatic input

32

transistor

33

pneumatic output

35

Valve member

36

Control logic

40

Electronics circuit board

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015116464 A1 [0004]

Claims (16)

Solenoid valve (10) in particular for an electropneumatic drive, which is used in particular in a process engineering system, comprising: an in particular ring-shaped magnet coil (18); a magnetic yoke (14) receiving a magnet coil (18) and made of a magnetizable material, on the inside of which an armature (12) is movably arranged and on the outside of which at least partially surrounds the magnet coil (18); a magnetic field sensor (22), in particular a Hall sensor, for detecting, in particular measuring, the magnetic flux density; characterized in that a profile jump, such as a profile recess, for example a groove (20), is formed on the outside of the magnetic yoke (14), the magnetic field sensor (22) being arranged in the region of the profile jump. Solenoid valve (10) after Claim 1 , characterized in that the profile jump is designed as a profile recess, such as a groove (20), an air gap being present in particular between the magnetic field sensor (22) arranged in the profile recess (20) and a wall of the profile recess (20) and / or that the profile recess (20) is made in the form of a blind hole and / or circumferentially in the magnetic yoke (14) and / or a measuring point of the magnetic field sensor (42) is arranged within the profile recess, the magnetic field sensor (22) in particular being arranged such that it the profile recess protrudes. Solenoid valve (10) after Claim 1 or 2nd , characterized in that the magnetic field sensor (22) is designed to detect an overshoot and / or undershoot of a predetermined magnetic field strength, such as a solenoid valve switching threshold (armature pulled up / armature dropped out), in accordance with a corresponding status signal, such as an overshoot signal or can emit an undershoot signal, in particular to control electronics (24) which preferably cause energization of the magnetic coil (18); and / or that the magnetic field sensor is designed to use a magnetic flux in the area of the profile recess (20) to determine the position of the armature (12), in particular along its translational travel path. Solenoid valve (10) after Claim 1 The armature (12) is supported on the yoke (14), in particular a core (16) of the yoke (14) via a spring element (19) and in particular in an end position of the solenoid valve (10) between the armature (12) and the core (16) is formed a working air gap (25), the size of which varies in a translational setting direction (A) due to the retraction and extension of the armature (12); and / or wherein the armature (12) is forced into an extended end position by a spring element (19) when the magnetic field is not present; the armature (12) being magnetically attracted to the core (16) when the magnetic field is applied to a retracted position. Solenoid valve (10) according to one of the preceding claims, wherein it comprises control electronics (24) which is designed to deliver a pull-in current or a holding current as excitation current to the solenoid coil (18), in particular the pull-in current being set such that the Armature (12) moved into the in particular retracted end position; The control electronics (24) in particular are designed to deliver a holding current to the magnet coil (18) as an excitation current as soon as the armature (12) is in a particularly retracted end position, the holding current in particular being set such that it is lower than that Is pull-in current and / or holds the armature in the retracted end position, and / or a control circuit board of the control electronics (24) directly receives the magnetic field sensor (22). Solenoid valve (10) according to one of the preceding claims, wherein the profile jump is dimensioned such that the yoke (14), preferably an iron yoke, in the area of the profile jump when the excitation current is applied is in a magnetic saturation state, preferably slightly exceeds the limit of the saturation state by in particular to spend or hold the anchor (12) in the retracted or extended end position in particular. Solenoid valve (10) according to one of the preceding claims, wherein the magnetic field sensor (22) is designed to detect the state of saturation in the profile jump and to output a first signal, preferably to signal that the armature (12) is in a tightened state or held state in the retracted position, and / or the magnetic field sensor (22) is designed to detect whether there is a saturation state in the region of the profile projection and to output a second signal, preferably to signal that the armature (12) in Direction of the extended position. Electronic control (24) for confirming a solenoid valve (10) designed in particular according to one of the preceding claims, in particular for an electropneumatic drive, which is used in particular in a process engineering system, the solenoid valve (10) between an on-switching state and an off-switching state can be spent; comprising a supply output for applying an excitation current a coil (18) of the solenoid valve (10) for moving the solenoid valve (10) from the off-switching state to the on-switching state; a switching regulator for setting the excitation current on the coil (18), the switching regulator being designed to apply a pull-in current to the coil (18) of the solenoid valve (10) when it is brought into the on-switching state and for holding the on-switching state subsequently Holding current applied to the coil (18), which is lower than the pull-in current. Electronic control (24) after Claim 8 , It has a sensor, in particular a magnetic field sensor (22), for detecting whether the solenoid valve (10) has reached a specific switching state, such as the on-switching state, the sensor being applied to the electronic control (24) Input voltage is electrically supplied and / or the sensor is arranged in a recess, such as a groove (20), a metal body, such as a yoke, of the magnetic yoke (18), and / or it comprises a circuit board for power electronics of the switching regulator, the Magnetic sensor located on the circuit board is arranged in a recess, such as a groove (20), of a metal body, such as a yoke, of the magnetic yoke (18) Electronic control after Claim 8 or 9 , wherein the switching regulator (24) has a resistor (26), preferably a shunt resistor, which is connected in series with the coil (18) and is designed to generate a voltage drop which substantially corresponds to the increase in the current applied to the coil (18) , a comparator (28), which monitors the voltage drop across the resistor (26) with respect to a threshold value, a transistor (32), preferably a metal oxide semiconductor field effect transistor (MOSFET), which, when this threshold value is reached, the current flow to the coil ( 18) interrupts, and a freewheeling diode (30) connected in particular in parallel with the coil removes the current in the coil (18) when the comparator (28) interrupts the current flow; the transistor (32) in particular closes automatically after a predetermined time, preferably in the range of at least one microsecond, so that in particular the current flow from the coil (18) towards the ground increases again, in particular when the threshold value is reached again by the comparator ( 28) is interrupted; wherein the threshold value in the comparator (28) for regulating from a pull-in current to a holding current can be regulated to a lower threshold value, so that the excitation current in the coil (18) can be regulated to the desired holding current. Electronic control (24) according to one of the Claims 8 to 10th which according to the steps of one of the Claims 12 to 14 defined method for controlling a solenoid valve (10). Method for controlling a particular one of the Claims 1 - 7 Trained solenoid valve, in particular for an electropneumatic drive, which is used in particular in a process engineering system, wherein: the solenoid valve (10) can be moved between an on-switching state and an off-switching state; in order to move the solenoid valve (10) from the off-switching state to the on-switching state, a pull-in current is applied to a coil (18) of the solenoid valve (10); in the switched-on state, the pull-in current remains applied to the coil (18) for a pull-in time and a holding current is applied to the coil (18) after the pull-in time, which is lower than the pull-in current. Procedure according to Claim 12 , wherein: during the application of the holding current to the coil (18) by means of a sensor, preferably a magnetic field sensor (22), the on-state of the solenoid valve (10) is monitored whether the solenoid valve (10) leaves the on-state, and , the solenoid valve (10) should leave the on-switching state, the pull-in current is applied to the coil (18), in particular leaving the specific switching state of the solenoid valve (10) by detecting an increase in a magnetic resistance of the magnetic metal circuit in the area of the magnetic yoke (14) of the solenoid valve, in particular in the region of a weakening, such as a depression, for example a groove (20), is determined in a metal body of the magnetic yoke (14). Procedure according to Claim 14 or 15 , wherein: the holding current is only applied when a specific switching state of the solenoid valve (10), preferably the on-switching state, is reached, in particular when the specific switching state is reached by means of a sensor, in particular a magnetic field sensor (22), which, in particular, can detect the strength of a stray field on the outside (9, 21) of a metal body of a yoke (18) of the solenoid valve (10), and / or if the holding current is applied, the pull-in current is then reapplied to the coil (18), if a deviation of the solenoid valve (10), in particular determined in advance from the specific switching state, preferably from the on-switching state, in particular from a sensor, such as a magnetic field sensor (22), is detected. Procedure according to Claim 12 or 13 wherein an armature (12) of the solenoid valve (10) is brought into a retracted position, such as an open position The method includes the method steps: detecting a drop in the armature in the direction of an extended position, in particular by a sensor, such as a magnetic field sensor (22), and then outputting a pull-in current signal to the coil of the solenoid valve (10) and / or to an electronic control (24) for applying the pull-in current to the coil (18), and / or detecting when the armature (12) has been reached and / or remained in the retracted position and then outputting a holding current signal to the coil (18) of the solenoid valve (10) and / or to the electronic control (24) for applying the holding current to the coil (18). Procedure according to Claim 12 to 14 , further comprising the steps: detecting in particular by the electronic control (24) whether the pull-in current and possibly the holding current signal are present, and then signaling that the armature (12) is in the retracted position.

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