CN1365268A - Method and apparatus for sealing capsules and capsules suitable for use in said method and apparatus - Google Patents

Abstract

The invention is concerned with a method of sealing a hardshell capsule having coaxial body parts which overlap when telescopically joined with each other, thereby forming a gap around a circumference of the capsule, comprising the steps of individually applying a sealing liquid including a solvent uniformly to the external edge of the gap of a capsule to be sealed to form a liquid ring around the circumference of the capsule, removing excess sealing liquid from the exterior of the capsule, drying the capsule by applying thermal energy from outside while gently tumbling and conveying the capsule on a spiral path.

Description

Method and device for sealing capsules and capsules suitable for the method and device

The present invention relates to methods and apparatus for sealing snap-fit capsules having coaxial partially overlapping capsule portions by sequential application of solvent and thermal energy. The invention further relates to capsule designs particularly suitable for such methods and devices.

Capsules to be sealed using the present invention are preferably hard shell gelatin capsules or other capsules made from those materials or combinations thereof which are pharmaceutically acceptable in terms of chemical and physical properties.

The problem that this type of capsule needs to solve compared to other dosage forms is the fact that the coaxial capsule body part must be well sealed in order to avoid any leakage of the contents to the outside or to avoid its contamination. Furthermore, damage to the contents or the capsule itself for safety purposes should be obvious and visible from the outside, and any technique for sealing capsules must be suitable for large-scale mass production to reduce manufacturing time and cost and reduce product defects due to waste caused by products.

EP0116743A1 and EP0116744A1 respectively disclose similar methods and apparatus for sealing such capsules having a hard-shell coaxial closure and a capsule body portion which would overlap when inserted into engagement. The method used involves the steps of immersing a batch of capsules randomly oriented in a mesh cage or with their lid portion oriented upwards in a sealing liquid, creating capillary action at the overlap of the lid and body portions, or A sealing liquid or its vapor is sprayed onto the overlapping seam, a blower is used to remove the sealing liquid from the surface of the capsule, and thermal energy is applied to the capsule as the cage is conveyed through the dryer. Both documents disclose the use of a wide range of sealing liquids and specific temperatures and patterns of applied thermal energy, the disclosures of which are incorporated herein by reference.

EP-0180543A1 also discloses a method for sealing an insert-engaged capsule having coaxial capsule portions, the method comprising sequentially applying a sealing liquid into the overlapping region of the junction between the cap and the capsule , removing excess sealing liquid, and applying thermal energy to dry. This document describes in particular various capsule designs suitable for use in such methods, which have ridges in the lid and/or body to facilitate accurate coaxial positioning of the lid and body. The disclosure of this document is also incorporated herein by reference.

Existing systems for sealing insert-engaged capsules having coaxial capsule portions by sequential application of solvent and application of thermal energy are partially inadequate with regard to the quality of the seal and the controllability of the various process parameters affecting the quality of the seal.

The present invention seeks to provide an improved method and apparatus for sealing insert-engaged capsules having coaxial partially overlapping capsule portions by sequential application of solvent and thermal energy, and an improved capsule design particularly suited for such methods and apparatus.

To this end, the present invention provides a method and apparatus and a capsule design for sealing a insert-engaged capsule having coaxial partially overlapping capsule portions as defined in the appended claims.

The present invention will now be described in more detail with reference to the accompanying drawings, using examples in which:

Figure 1 shows a magnified view of the overlapping sealing parts of a capsule according to the invention, and

Figure 2 shows the schematic structure of the drying cage used in the method and apparatus of the present invention and the path of the capsules during operation.

First, a general illustration of a system and capsule comprising the method and apparatus of the invention is given to highlight the key structural features and aspects of the invention. The enumeration below is not sequential or comprehensive, but simply covers the aspects in which the system of the present invention differs from prior art methods.

The present invention provides the following aspects:

It does not require an oriented capsule, simplifying the operation and increasing the reliability of the method.

The application of the sealing liquid is spatially controlled to optimize the wetted area for a good seal, the lowest tack and the fastest drying.

The temperature of the sealing liquid can be controlled to achieve efficient capillary action and optimum dissolution rate. This means that heating and cooling systems are used, e.g. systems using gelatin capsules require temperatures above ambient, whereas HPMC (hydroxypropylmethylcellulose) systems dry well with hot solvents and ambient temperatures.

The volume of sealing liquid applied to the space around the gap between the capsule body part (ie the cover and the body) is adjustable to prevent over wetting.

The sealing liquid is evenly applied around the capsule to achieve the desired full area seal.

Gas injection and/or suction is used to remove excess sealing liquid.

The system is designed so that capsule size changes require minimal compositional changes.

The system is designed to operate with a range of sealing liquids including but not limited to alcohol/water mixtures for gelatin capsules as described in EP0116743A1 and EP0116744A1 which are incorporated herein by reference. For capsules made from other materials such as starch, HPMC, etc., other solvent systems are required. The present invention provides various means of controlling key sealing and drying parameters such as temperature, solvent formulation, time, air flow, enabling the use of an optimal method and good control over it.

The transport of the capsules after sealing is effected in such a way that contact between the capsules and the surface of the device and between the capsules is minimized to reduce the risk of sticking or cosmetic damage.

The rate of drying of the capsules is carefully controlled to ensure that the inner overlapping surfaces are firmly bonded to each other as the solvent evaporates without the fluid having time to diffuse into the bulk of the capsule material.

Reliable bonding on the lid and capsule requires overlapping surfaces to be in contact under conditions in which the surfaces will fuse and join with strength for a time comparable to the minimum time required for entanglement of long-chain gelatin molecules. This sets the drying speed that the system will regulate.

The contact pressure between the surfaces to be bonded is maintained by a combination of interfering forces derived from precise production control of the capsules and expansion of the capsules due to fluid absorption.

Drying at a uniform rate across all surfaces is required to avoid distortion or poor sealing action, and can be achieved by the capsule inversion mechanism of the air-blown, drying cage device of the present invention.

The drying process can be carried out by controlling the temperature of the airflow, selecting the flow rate and humidity, so as to achieve the temperature, time and humidity conditions required for the strong bonding of the capsules.

The capsules are dried in a drying cage device that enables controlled delivery speed while inverting the capsules to ensure that the entire surface is dried evenly and that the capsules do not stick together.

The surface, material and form of the screw conveyors in the drying cage device are designed to ensure that capsules are not retained therein and are minimally damaged by contact with them during handling.

The porosity of the structure making up the drying cage device is designed to ensure low airflow resistance and uniform airflow over the capsules.

Two or more high velocity air nozzles, adjustable in width and position, are directed upwards in a line along the lowest point of the drying cage device, at a velocity sufficient to lift any capsules that tend to adhere to the surface.

The rotational speed control of the drying cage device allows the drying time to be controlled since the axial slip rate is a function of the rotational speed.

The control of the drying air parameters is achieved by using a servo control system in order to maintain a uniform state even in the presence of external variations.

The operation of the total sealing system is done in a small footprint self-contained device, making it compatible with the device in the capsule filling line environment.

The system of the present invention is therefore capable of sealing liquid-filled capsules immediately after filling at a speed comparable to conventional capsule filling lines.

Since the device of the present invention can be fed from a standard hopper, it is not necessary to closely connect the discharge port of the filler with the feed port of the sealing device of the present invention. This allows a buffer volume to be used to smooth the production flow to accommodate short downtimes of filling or sealing equipment.

The basic improvement of the method and apparatus of the present invention over prior art sealing systems consists in the control of the slit geometry of the capsule body portion to ensure a completely uniform capillarity along the entire overlapping length, and the A drying method or design of suitable equipment which removes the solvent in such a way that the gap is completely closed and the capsule parts adhere well together.

                                        

The capsule design most suitable for use in the sealing system of the present invention consists of two halves which partially overlap concentrically when snapped together. The basic method of sealing between the two halves is to introduce a solvent or sealing liquid into the gap between the two halves in the overlapping area so that when the solvent evaporates, the inner surfaces come into contact in a softened state and fuse together .

In order to achieve a good seal with this method, it is necessary that the sealing liquid, ie the solvent, must be filled in all the gaps between the two surfaces to be bonded together. For capsules, this is the total length of the overlap between the lid and body. The two surfaces that need to be bonded together tend to react with the solvent so that the inner surface is soft and tacky when they are brought together into a bonded relationship. This can be achieved by controlling the temperature and time at which the solvent is in the gap before the solvent evaporates bringing the two surfaces into contact with each other. Finally, the action of solvent removal requires the application of external force to the two surfaces to be bonded in order to hold them together in bonded form.

The present invention addresses these issues in capsule design, solvent application and drying mechanism.

In order to support uniform filling of the solvent in the gap, the capsule is designed with structural features that evenly separate the two surfaces by a predetermined distance while introducing the solvent into the gap. If the gap is wider in some places and not in others, the distribution of solvent over the entire area changes, resulting in a poor seal at some points around the capsule. The gap is completely closed when the solvent is removed and the bond is formed. This closing force has a finite strength, so that any resistance to the two surfaces being pulled together reduces the bond strength. Additionally, the capsule design is preferably such that contamination of the crevice by the capsule product is prevented since the product within the capsule is not a solvent for the capsule material and if it penetrates into the crevice it will block the action of the sealing solvent.

An important aspect of the present invention is the precision due to which all these requirements can be controlled by the tolerances of the capsule manufacturing industry and the various parameters of the sealing system such as temperature, time, solvent volume, solvent position, drying conditions accomplish.

There are various designs for capsules in order to achieve the required gap control while maintaining all other requirements of the capsule, such as appearance, manufacturability, ease of swallowing, etc. Several suitable designs have been incorporated by reference into the disclosure content of EP-0180543A1. A preferred embodiment uses a symmetrical arrangement of at least 3 bumps within the capsule, which optionally lock into recesses or grooves within the closure. These features provide axial positioning and maintain the closure in a concentric position with the balloon to provide a uniform gap. Specific examples include one or more variations such as axially raised rings and mating grooves, uniform rough surfaces on one or more faces, multiple protrusions and recesses, multiple annular grooves and recesses, and Ridges and valleys.

The size of the gap is selected so that the volume of solvent capillary is sufficient to infuse the inner surface of the gap, thereby modifying the surface sufficiently to make it soft and viscous so that the two surfaces bond when pressed together. This volume will depend on the material, temperature and force applied to bond the two surfaces. Typically, the gap is in the range of 0.05mm to 0.5mm. Typically, the volume of solvent required to initially fill the gap is between 5 μl and 20 μl.

In order for the gap to close when the solvent is removed, some tolerance must be allowed for movement. This can be achieved through a number of designs, the common structural feature is that the design does not allow these structural features to extend into the gap, the design remains sufficiently rigid to prevent the gap from closing. When spaced features are used, then a design with spaced features deformed by softening under the action of the solvent to allow the desired movement is particularly desirable. An example of such a structural feature is shown in FIG. 1 .

The geometry of the spacing features shown in this figure should be such that there is peripheral space for the material of the protrusion to flow in when the slit is closed. Corresponding designs of other embodiments are possible, as long as the principle of allowing deformation of the shaped body to accommodate the minimum flow is complied with.

Preventing product from infusing into the crevice area in the presence of a solvent would require providing a seal at the end of the crevice exposed to the interior region of the capsule, providing positive pressure from the outside of the capsule to the inside to prevent product from flowing into the crevice, and/or immobilizing the product. to prevent it from flowing into narrow gaps.

A preferred embodiment of the capsule used in the method and apparatus of the invention is to seal the top of the slit by a suitable design featuring a snap-fit feature.

Solvent application

A second requirement for sealing is to modify the inner surface of the gap between the lid and bladder so that they become soft and tacky when they fit together. As previously stated, this requires control of the type and amount of sealing liquid or solvent and its temperature. The present invention provides the principles for realizing this concept using a number of solvents of the type described in prior patent applications related to the art or incorporated by reference. The use of capsules with well-controlled gaps sealing the contents apart facilitates impregnation of the interior surfaces with the desired volume of solvent.

In a preferred embodiment of the invention, the solvent is delivered uniformly along the circumference to the outer edge of the gap. Surface tension allows solvent to be drawn up evenly from the outside into the crevices, as long as the crevice spacing is even. To prevent softening of the outer surfaces, remove any excess solvent as quickly as possible.

Various techniques are available to apply solvent to the slit, including: a spray from several points around the capsule towards the outer edge of the slit for a time designed to distribute the appropriate volume of solvent on the capsule; e.g. Embodiments described above, wherein the nozzles are replaced by an array of piezoelectric or heated inkjet heads that dispense the appropriate solvent, arrangements of sponges, brushes, wicking strips, etc. that transfer the solvent by contact to the desired location; and the solvent The steam nozzle is aimed at the open end of the slit to condense the steam directly on the capsule.

In addition to distributing the desired volume evenly around the slit entrance, the system must remove any excess liquid solvent on the capsule surface prior to softening the capsule material. This can be achieved by various means including suction to suck liquid away, air jets to blow liquid off surfaces, wicking liquid by contact, centrifugal force to throw excess liquid, oscillation to remove excess liquid or these combination of measures.

A preferred embodiment of the sealing device of the present invention uses 3 nozzles spaced 120° along the circumference, directed at the outer opening of the overlapping gap, wherein excess liquid is removed by a combination of air injection and suction. In addition to precise control of the volume and location of solvent application, the temperature of the capsule, solvent and atmosphere need to be kept within defined limits. The level of control required depends on the diversity of materials and circumstances. The equipment is fitted with a suitable temperature control system to provide suitable operating conditions over a wide range of environments.

Solvent removal

The third requirement is to remove the solvent from the crevices in such a way that a force is created to hold the two surfaces together as they dry. The final method of solvent removal is as a vapor whose transport is achieved by entrainment in a gas stream at an appropriate temperature. Solvent transport from the gap to the air can be achieved by several principles, such as flow along the gap to support evaporation from the exposed liquid surface, evaporation from the outer surface by diffusion of the capsule cover material, diffusion by the capsule body material and contact with the contained liquid. The fluid mixes or absorbs into the content fluid, and diffuses and binds to the capsule material of both the cap and the capsule body.

All of these methods are able to participate in the drying process in a way that removes the solvent but does not introduce air. As this process occurs, atmospheric pressure forces the lid and bladder surfaces together at a pressure of up to 100,000 N/ ^m2 .

All of these transport mechanisms are accelerated if the temperature is increased. However, excessive temperatures can lead to the following situations: prevent the formation of a good bond, such as bubble formation and distorted surfaces, excessive flow rates in the liquid lead to air entrapment, internal pressure increases so that air is expelled from the inside of the capsule through the gaps, Thermal stress distorts the capsule, or excessive drying of the outer surface increases the stiffness against closure.

The present invention optimizes the temperature and air flow so that the drying of the capsules takes place at an industrially acceptable rate without compromising the quality of the seal, by any of the principles described above.

In the following, preferred embodiments of the apparatus for sealing capsules are described in detail.

In a preferred embodiment, all requirements and equipment for effective sealing are implemented in a self-contained machine.

This embodiment has an input hopper that accepts capsules from any source at any rate. Typically the capsules are fed by using a conveyor belt or air conveying system.

Capsules at this stage are mechanically held closed by a number of structural features in the capsule lid and body, and have a sealing system to provide a partial seal that prevents the contents of the capsule from escaping during mechanical transfer .

The hopper is designed to feed the capsules at several feed tubes, which convey the capsules into the sealing device. Capsules are fed by gravity from a hopper into the tube, the movement of the capsules is by means of the feed tube at a distance between 0.5 cm and 5.0 cm and a reciprocating vertical at a rate designed to ensure smooth, blockage free movement sports.

An optional capsule orientation device can be inserted between the hopper and the input tube to ensure that the capsules enter the tube in a predetermined orientation. This feature is not required for an effective seal, but can be used in conjunction with a reduced jet spray head design to minimize the volume of solvent used or to limit softening of the outer surface of the capsule.

In one embodiment six inlet tubes are used, this number is taken as an example for the subsequent description, however, embodiments with any number of parallel paths may be used to meet the required throughput.

The capsule in the infusion tube is prevented from moving by a mechanical lock, and its opening cycle is controlled by the system controller. In order to achieve the sealing function, the various actions must be utilized with precise timing and various relationships. In a preferred embodiment, all of these actions are controlled through the use of a programmable logic controller (PLC), so that the program and timing can be adjusted to meet the requirements of various solvent systems, to accommodate different capsule designs and materials. A feature of the invention is that the PLC enables a single machine to operate with different methods, materials and capsule sizes.

The action required by the controller can be achieved by using a combination of regulators including, but not limited to, solenoids, pneumatic valves and cylinders, motors and cams.

At the beginning of the sealing cycle, the PLC releases the locks holding the capsules and lets the leading capsule in each tube drop into position for sealing. This point is called the spray bar. The spout has a mechanism to hold the capsule in place and the solvent is sprayed onto the middle portion of the capsule so that it evenly contacts around the trailing end of the overlapping portion capped on the capsule body. This can be achieved by surrounding each capsule with an annular manifold provided with a number of small holes. The positions and angles of these holes are such that liquid ejected from them will reach the capsule at the intended location. When the capsule is not oriented, then the area on the capsule encountered by the solvent must be such that whatever the orientation of the capsule, the trailing end of the gap is covered in solvent. When the capsule is oriented, the area covered by solvent can be reduced to an area just around the trailing end of the slit. To achieve the desired coverage, the holes are angled, typically 45°, and spaced evenly around the capsule.

The spouts have a number of holes, typically 6, for each of the capsule input tubes, and the liquid is delivered into the nozzles through a branch within the spout. The liquid is forced to spray from the nozzle onto the capsule by connecting the liquid to a permanent pressurized source via a control valve to pressurize the liquid. By adjusting the time the valve is open and the pressure of the pressure supply source, the form and volume of solvent dispensed to the capsule can be controlled by the EFD valve controller. To prevent solvent transfer when not needed, additional interlock valves can be configured in the transfer line.

The system typically delivers a liquid volume of 20 μl to 200 μl to each capsule, using pressures in the range of 1 bar gauge to 5 bar gauge and injection times between 0.1 seconds and 1.0 seconds, depending on capsule size and Material.

The velocity and volume of solvent flow into the annular space around the capsule can be adjusted in a desired pattern to ensure uniform penetration of the solvent into the gap between the cap and capsule body. This includes conditions such as high speeds forming an aerosol mist, medium speeds forming a jet of liquid onto a surface, and low speeds forming a liquid ring that expands just to touch the capsule.

This system delivers more solvent into the capsule than can be absorbed into the crevices, in order to ensure that all areas are adequately supplied with solvent. Excess solution is removed from around the capsule by negative pressure suction and/or air jets. This action can also be controlled by the PLC, using an additional row of holes located near the nozzle to remove air/solvent from the area around each capsule. These holes are interconnected by means of a second manifold within the nozzle and thus into a vacuum pump and a collector where the solvent vapor condenses and the liquid is trapped.

At the end of solvent spraying and excess solvent removal, the capsule has let solvent into the crevices, but it is still tacky due to the action of the solvent on the outer surface. The capsule must be dried under carefully controlled conditions so that the seal is properly formed and the capsule does not stick or become cosmetically damaged by sticking to other surfaces.

This is accomplished in a preferred embodiment by rotating the spout away from the inlet tube so that entry ports line the capsules into the drying cage. This can be achieved by mounting the nozzle in a rotatable cylinder. To eject the capsules from the nozzle, the cylinder is rotated through 120° and the capsules are expelled using the combined action of the push rod and the air jet. Capsules drop from each input tube into one end of the drying cage at an angle of 60° relative to the vertical.

In order to maintain high throughput, the cylinder with nozzles installed has holders to hold 3 nozzles at 120° intervals. This rotational expulsion (capsule) leads to the introduction of a new nozzle below the input pipe, ready for the start of the next cycle.

Additional features allow the spout barrel to rotate in the opposite direction when directed by the PLC, and allow the capsules to be expelled into a separate shute that is not fed into the barrel but delivered to a separate outlet. This enables the capsules to be ejected from the machine after sealing, but before drying, for diagnostic purposes or for process measurements.

In order to operate the machine with capsules of different sizes but maintain precise control of the capsule feeding and sealing operations, some hardware changes are required to account for the capsule size variation. Preferred embodiments limit these changes to a few easily accessible items, such as inlet pipe assemblies, nozzles, and outlet screens.

Additionally, to ensure that the machine is functioning correctly, a number of sensors may be used to ensure that the capsules and fluids are normal and delivered correctly. These include optical sensors at the feed hopper to determine if the capsules are healthy, fiber optic sensors in the tube between the spout and the drum dryer, pressure and vacuum sensors in place, and flow sensors.

The cage (into which the capsule is expelled after filling) comprises a tubular mesh arrangement with internal helical guides. The cylinder rotates slowly so that the internal helix causes the capsule (which falls off the sides as it is lifted by the rotation) to move along the axis of the cylinder. In this way, the capsule gently inverts along the cylinder following the helical trajectory of the internal helical guide.

Drying cage function

The conditions under which the capsule is dried after the solvent has been introduced into the crevice are the key factors for obtaining a good sealing effect. The key functions that need to be achieved in drying are:

- the capsules are transported through the drying zone to the bulk storage container;

- Control the time of the capsules in the drying area to ensure that the capsules are fully dry and no longer sticking when they enter the bulk storage container;

- Air flows over the capsules for quick and even drying;

- Minimize capsule-to-capsule contact to prevent them from sticking;

- Minimize contact of the capsule with the cage, preventing sticking to the walls; and

- Minimizes mechanical shock and prevents breakage.

The drying cage device preferably has a design comprising a columnar structure mainly made of stainless steel mesh. Preferably the inner material of the double helical guide also belongs to the stainless steel material.

The dimensions of the cylinder are preferably between 600 and 1,000mm in length and between 100mm and 200mm in diameter, with a length of 800mm and a diameter of 160mm being a preferred embodiment. The ratio of diameter to length is chosen to control the mechanical properties, the length being a function of the time required in the drying zone and the diameter being a function of the amount of capsules to be processed.

In this embodiment having the dimensions described above, the length is chosen so as to produce a residence time of the capsules in the drying cage of between 10 and 100 seconds.

The cylindrical drying cage is oriented with its axis horizontal. In a preferred embodiment, the cage is driven by rollers, allowing it to rotate freely along a horizontal axis. The rollers are manufactured with sufficient functionality to enable one of the rollers to be driven to cause the drying cage to rotate or to directly drive the cage by coupling at one end. The means of support and rotational drive must provide free airflow throughout the cage and be compatible with washing and maintaining cleanliness.

In one embodiment, the inner double helix functions to cause the capsule to flip in one axis when the cage is rotated. The pitch and form of the helix is critical to ensure that all capsules are conveyed axially at the same rate. In this embodiment, the spiral is formed from blades extending from the central axis to the web of the cylinder. Each blade is composed of two single petals, and the two single petals extend diametrically from the central axis to the cylindrical wire mesh. Each blade is mounted on a shaft to rotate at a fixed angle relative to its neighbors. This angle is typically 12 degrees. The blades are compression molded from stainless steel sheet typically having a thickness of 0.75 mm and are optionally coated with PTFE to ensure low surface energy. The attachment of the blades to the shaft and cylinder is achieved by mechanical fittings incorporated in their design. For this purpose, the shaft has circular grooves to accommodate the blades at intervals chosen to provide the required helical pitch. This pitch is typically 5.993mm for 118 blades, resulting in a double helix structure with a helix pitch of 179.8mm. The shaft has diametrically opposed flats and the vanes have corresponding structural profiles in their central bores to enable the vanes to slide onto the shaft and lock onto the shaft by rotation at the desired grooves. The mounting and fixation of the blades on the cylinder is achieved by grooves on the outer profile of the blades, which match the axial lines attached to the inside of the cylindrical mesh. In a typical implementation, 30 wires spaced 12° apart are used to match the vane arrangement. Assembly of the blade into the cage is accomplished by sliding the blade onto the shaft and rotating until it locks into place. The mesh of the outer cylinder is constructed to accommodate the capsule and provide a secure fitment for the vanes, while maximizing the open area to allow good air flow. To achieve this, 134 individual loops of 0.16 mm diameter stainless steel wire were welded along 30 longitudinal wires of 0.2 mm diameter stainless steel arranged in increments of 121 along the circumference. The longitudinal wires are inside the circumferential wires so that they can be used as fixed parts of the blade.

Another embodiment uses separate cages constructed from separate sections for easier drainage. In this embodiment, a 3cm helical configuration was used such that each helix had a helix pitch of 240mm and the cage had an inner diameter of 185mm. The cage exterior and helical arms are fabricated from flat die stampings, each with 3 arms and with edges that create a castellation so that when stacked together at a complementary angle of 6° along the central axis, the layers pass through The castellations were spaced at approximately 4mm intervals and formed an internal spiral with the required pitch. Known features interlock the parts together so that all parts are driven from one end to rotate.

The configuration of the drying cage in the previously described embodiments is an example of a means of achieving the required transport conditions for the capsules as they pass through the drying zone. The concept can also be realized using various design and construction techniques. This includes, but is not limited to, rectangular cross-section cages with flat angled baffles arranged in such a way that capsules migrate above the cage in one direction as the cage rotates, as shown in Figure 2.

A rectangular cross-section can significantly reduce production costs.

Another alternative is a conveyor belt system where the conveyor belt has an open mesh structure to allow air to circulate around the capsules, where vibration or air jets can optionally be used to prevent the capsules from sticking together or to Either on a conveyor belt, or a counterflow dropper, where warm air is delivered to the bottom of the riser at a rate regulated so that the weight of the capsule is just slightly greater than the aerodynamic resistance of the upward airflow. The downward movement speed of the capsule can thus be adjusted by adjusting the air flow speed, allowing sufficient delivery time to dry off excess fluid.

In yet another preferred embodiment of the cylindrical drying cage device, the central structural feature has branches forming 3 interwoven helices, the helices being angled such that the helix makes 2 to 4 revolutions along the length of the drying cage.

The open cell nature of both the outer cylinder and the helical arms allows air to flow through the drying cage to mix freely with the capsules.

The cage is installed by enclosing it in a surrounding hard-walled container with ventilation holes to allow air to enter and exit. Air enters through two or more axial slits in the bottom of the cage. The slit is dimensioned to ensure that the incoming air has a high velocity sufficient to lift the capsules from the inner surface of the cage to enhance the tumbling action and ensure that the capsules neither stick to the walls nor to each other. Air exits the chamber through a port located at the opposite end from the capsule feed.

The air fed to the drying cage comes from a compressor unit capable of delivering large volumes of air at high speeds. To condition the air to the required temperature, a heating or cooling heat exchanger is installed between the compressor and the slot inlet point. The air entering the compressor from the room is raised in temperature by the action of compression and, without additional conditioning, enters the dryer at a temperature between ambient and 30°C above ambient. This temperature range can be controlled within the range of 5°C to 80°C by heating or cooling. The cooling heat exchanger is preferably an air-water system of the same design as used in motor vehicles. Exhaust air from the drying cage is drawn by an additional high capacity air pump which directs the air and solvent vapors away from the machine along the ventilation ducts.

The exhaust air can thus be vented indoors, to the outside air via ducts and chimneys or into a condenser/scrubber to remove solvents and treat the off-gases to be released.

The selection of the extraction system depends on the site of operation and the solvents used.

The use of high capacity supply and suction air pumps makes it possible to regulate the pressure inside the cage. At all points within the dryer, it is important that the pressure is below the room ambient pressure when it is necessary to avoid the release of solvent into the surrounding air. The PLC is able to control the two motors that drive the two pumps, so that pressure and flow can be adjusted independently.

The effect of the spiral in the drying cage means that the residence time of the capsules in the drying cage can be controlled simply by the speed of rotation. When the capsules reach the end of the cage, they fall into a sieve and then into a storage container or onto a conveyor mechanism.

When the solvent used should not be released into the room air, additional structural features can be included in the system to ensure that all solvent is removed by air purge. These include: a protective shield around the nozzle cylinder assembly which forms a substantially closed space connected to the exhaust pump to ensure that any vapors released in this area are removed, a transparent shield installed in place of the inlet pipe assembly Shielding, which allows the operator to observe the nozzles with solvent poured into them before starting the sealing operation, as a method of visual inspection of their performance, by pressure balancing the gas flow to ensure that the entire space containing solvent is kept below At atmospheric pressure, the airflow setting at the outlet allows the capsules to exit without loss of solvent vapor, in extreme cases the capsules leaving the dryer can be contained in a sealed container through which air is blown into the exhaust to remove any residue Solvent vapors, by controlling interlocks to prevent entry into the liquid feed section of the machine after a certain period of time after spraying, and/or selecting all materials in contact with liquid or solvent vapors, ensure that there is no prolonged degradation.

Claims (11)

1. sealing has the method for the hard-shell capsule of coaxial utricule part, and wherein utricule can be overlapping when being bonded with each other in the mode of imbedding, thereby formed the slit around capsular circumference, and this method may further comprise the steps:

The seal fluid that will comprise solvent separately is applied on the outward flange in capsule slit of needs sealing equably, so that around capsular circumference, form pendular ring,

Remove excessive seal fluid from capsular outside,

By in spiral passageway, applying the dry capsule of heat energy from the outside in upset leniently and the delivery capsule.

2. the process of claim 1 wherein excessive seal fluid by aerojet and suction and be used for removing.

3. claim 1 or 2 method are wherein controlled flow velocity, so that just touch capsular pendular ring after being formed on expansion in applying the process of seal fluid.

4. be used to seal the equipment of the hard-shell capsule with coaxial utricule part, wherein utricule can be overlapping when being bonded with each other in the mode of imbedding, thereby formed the slit around capsular circumference, and this equipment comprises:

The seal fluid that is used for will comprising individually solvent is applied on the outward flange in capsule slit of needs sealing equably so that form the device of pendular ring around capsular circumference,

Be used for removing the device of excessive seal fluid from capsular outside,

Be used for by leniently overturn at spiral passageway and delivery capsule in apply the dry capsular device of heat energy from the outside.

5. the equipment of claim 4, the wherein said device that is used for applying separately seal fluid comprises: evenly spaced and point to a plurality of nozzles of overlapping slit outside opening and be used to control the device of seal fluid, capsule and the atmosphere temperature at place, slit around the capsule circumference.

6. claim 4 or 5 equipment, wherein saidly be used for dry capsular device and comprise rotatable cylindrical dry cage equipment, it has the inner vanes arrangement of extending along the axle of cylinder, and the arrangement mode of these blades makes that capsule overturns and carries when dry cage device rotates on spiral path.

7. the equipment of claim 6, the sclerine container that wherein said cylindrical dry cage device is had passage centers on, and the air that will provide after equipment will be regulated at full speed infeeds in the dry cage device with large volume.

8. claim 6 or 7 equipment, the straight angle baffle plate that wherein said dry cage device has rectangular cross section and arranges as inner vanes.

9. the capsule that has the coaxial utricule part of duricrust, it can be overlapping when being engaged with each other in the mode of imbedding, and utilize the enforcement that is used for of the solvent that is applied to the overlay region to seal, wherein provide spaced features so that in formation (uniformly) slit, overlay region, this spaced features structurally should make them softening under the effect of solvent, makes this slit closure thus.

10. the capsule of claim 9 wherein provides sealing function in the slot ends that is exposed to the capsule zone, flows in this slit with the product that prevents to be filled in this interior zone.

11. the capsule of claim 9 or 10, the product that wherein is filled in the interior zone is fixed to prevent that it from flowing in the described slit.

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