Patent Grant
8511350
The invention is broadly concerned with dispensing cartridges for fluid filling masses, in particular with multicomponent cartridges which are used for dispensing two or more components contemporaneously. In a multicomponent cartridge, each of the components is stored into its own storage chamber prior to dispensing. The storage chamber for each one of the components is separate from the storage chamber for any of the other components, such that the components may not mix during the storage period. The innovation pertains in particular to a cartridge comprising a piston setting device and a piston setting device for a cartridge as well as a method for operating a piston setting device to set a piston in said cartridge.
When filling a cartridge chamber of a cartridge with a filling mass, it is common practice to close the cartridge chamber by inserting a piston into the cartridge chamber containing the filling mass. That means a piston is set or inserted into the cartridge chamber. It is desirable not to trap air in the cartridge chamber during this setting operation due to the fact that air may be harmful for the component stored in the cartridge chamber and due to the fact that air as a compressible gas may cause the piston to tilt when moved for discharging the filling mass from the cartridge. Additionally, the presence of a compressible gas will cause a pressure variation inside the chamber during dispensing which creates undesirable variations in flow and may result in poor performance of discharged material.
According to DE 298 00 594 U, a micropore filter is inserted into a pocket formed in the piston. By means of this micropore filter, the air trapped between the filling mass and the piston can escape when the piston is inserted into the cartridge. Furthermore, this micropore filter is to prevent any emission of the filling mass. However, volatile components of the filling mass can penetrate the micropore filter, which may lead to leakage.
DE 295 06 800 U shows another ventilation device. Here, the ventilation is performed by means of a plurality of valve plugs mounted around a divided circle of the piston cover, and these plugs are lifted from valve cones when the piston is pressed into the cartridge, thus enabling the discharge of air. However, this ventilation device can only be manufactured with tight manufacturing tolerances. Another disadvantage can be seen in that parts of the filling mass can advance up to the valves, which are then contaminated, so that their sealing function is adversely affected.
A cartridge piston is also known from DE 200 10 417 U1. The piston has a first piston part which is provided with a sealing lip which is designed for contact with the cartridge wall. The first piston part has a circular cylindrical recess. Furthermore, the piston has a second piston part which has a circular cylindrical wall part which is latched to the first piston part at the base of the recess and thus forms a latch connection. The circular cylindrical wall part merges in arcuate form into a valve pin of a venting valve. This valve pin passes through a cylindrical bore arranged along the piston axis in the first piston part and has a valve cone which comes into contact with a valve lip of the first piston part. The latch connection is interrupted by a small air passage which forms a filter path between the circular cylindrical wall part and the first piston part. The filter path is made up of narrow passages at the inner wall of the circular cylindrical wall part.
If the cartridge piston is inserted into a cartridge, the valve pin is moved such that the venting valve is opened and the air enclosed between the filling mass and the cartridge piston escapes via the air passage and the filter path and is discharged via the venting valve. If the cartridge piston is pressed toward the filling mass, filling mass can move via the air passage up to the filter path, but is prevented by the labyrinth formed by the filter path from being discharged through the venting valve.
Additionally, many materials packaged in cartridges are very viscous and form irregular surfaces rendering current piston setting techniques ineffective. Such irregular surfaces are in general not flat, but may comprise a plurality of peaks and valleys of irregular shape.
It is the object of the invention to provide a cartridge piston with a piston setting device which allows for a faster setting of the piston, thus for higher discharge rate of air.
The system and the piston setting device according to the invention allows the extraction of unwanted air between the fluid mass and piston by creating a negative pressure differential between fluid mass and cartridge piston.
At the same time, the valve remains dry and free of dirt. Creeping, oil-like components of the filling masses should be prevented from leaking from the valve.
The invention relates to a system for filling cartridges, to a piston setting device for setting a piston within a cartridge filled with a filling mass and to a method of setting a piston in a cartridge.
The invention relates to a system comprising a piston setting device and a cartridge comprising a piston and a cartridge chamber which can be filled by a filling mass. The filling mass can be enclosed between a closed outlet opening and a piston. The piston comprises a first piston part which rests in a sealed manner against the cartridge wall and a second piston part, which forms a venting valve comprising a valve plug together with the first piston part. Said valve plug opens when a pressure is exerted on the side of the piston opposite to the filling mass by a piston setting device. When the valve plug opens, any air trapped between the filling mass and the piston can escape. The escaping air is sucked into a conduit arranged in the piston setting device leading to a vacuum source when the valve plug is opened. The piston setting device comprises a housing, a conduit arranged in said housing, said conduit having a first end and a second end, said first end comprising an attachment element connectable to a vacuum source and said second end comprising a plunger, said plunger being connectable to the valve plug of the piston for opening said valve plug when said piston setting device is attached to said piston. A vacuum tube can be attached to the attachment element.
The pressure differential between the cartridge chamber and the drive side of the piston is thereby increased. The drive side of the piston is the side of the piston opposite the filling mass, thus the side of the piston to which the piston setting device is attached to. As a consequence of the higher pressure differential, the air leaves the cartridge chamber more rapidly. Therefore the piston setting device can be operated at higher speed, which in turn allows for the displacement speed of the piston to be increased.
The piston setting device advantageously comprises a gasket for providing a sealing of said piston in said cartridge. Thereby the conduit in the piston setting device is sealed from the environment in order to apply a vacuum to said conduit.
The plunger contacts the valve plug of the venting valve of the piston, when said piston setting device is pushed against said piston. According to a first embodiment of the invention, said plunger can be an integral part of said piston setting device.
According to a second embodiment of the invention said piston setting device contains an interior plunger which is movable relative to said housing of said piston setting device.
The cartridge is fillable with a filling mass, the filling mass being enclosed by the piston and the cartridge wall, wherein the piston comprises a first piston part resting in a sealed manner against the cartridge wall and a second piston part, whereby a valve plug is formed by the first and second piston parts, said valve plug being opened for the passage of air trapped between the filling mass and the piston by the piston setting device when a pressure is exerted on a rear side of the piston.
A filter section is provided in the air passage between the first and second piston parts according to an advantageous embodiment of the invention.
This filter section has advantageously at least one narrow channel which forms a penetration barrier for the filling mass and ensures that the valve plug remains dry and free of dirt.
Advantageously the valve plug and the filter section are arranged concentrically to each other.
An outer region of the second piston part engages with the first piston part by an engagement connection, the engagement connection is interrupted by an air channel, and the filter section connects to the engagement connection.
The piston setting device is attached in a fluid-tight manner to said piston, A seal element can be provided between the piston setting device and the piston.
The piston setting device for a cartridge comprises a housing, a conduit arranged in said housing, said conduit having a first end and a second end, said first end comprising a plunger, said plunger being connectable to a venting valve of the piston comprising a valve plug for displacing said valve plug to an open position for allowing air to flow through the conduit and the second end comprising an attachment element connectable to a vacuum source.
Advantageously a vacuum tube is connected to the attachment element.
According to a preferred embodiment, the first end of the conduit has an inlet opening arranged adjacent said plunger. Alternatively the first end of the conduit may comprise a plurality of inlet openings. A plurality of inlet openings is in particular advantageous to increase the flow rate of the air. The inlet openings are preferably arranged circumferentially around the plunger, so that the flow path of the air is substantially the same regardless of the location of the passage at the engagement connection of the first piston part with the second piston part.
The inlet openings merge into the conduit prior the second end of the conduit. Thereby the air coming from a plurality of inlet openings can be collected to be directed to the outlet opening which is connected to the vacuum source. According to an advantageous embodiment, the attachment element may be plugged into the conduit. Alternatively a thread can be provided in the conduit for receiving the attachment element. The attachment element can be screwed into the thread.
Advantageously the housing can have an outer diameter which is smaller than the diameter of the piston. Thereby the housing can be introduced into the cartridge chamber at any desired position.
At least one inlet opening is arranged on the first end of the conduit on a face of the piston setting device, wherein the face of the piston setting device is the surface facing the piston. The outlet opening on the second end of the conduit is arranged in the wall of the piston setting device.
According to a second embodiment, the piston setting device for a cartridge comprises a housing, a conduit arranged in said housing, said conduit having a first end and a second end, said first end comprising a plunger, said plunger being connectable to a venting valve of the piston comprising a valve plug for displacing said valve plug to an open position for allowing air to flow through the conduit and the second end comprising an attachment element connectable to a vacuum source wherein said housing contains an interior plunger for closing the valve plug upon completion of the extraction of air. The interior plunger preferably has a longitudinal axis which is essentially coincident with the axis of the venting valve for closing the valve plug upon completion of the extraction of air.
The interior plunger is according to
Furthermore the invention relates to a method for setting a piston in a cartridge comprising the step of attaching a piston setting device to a piston in a fluid tight manner, opening a valve plug in the piston by actuating the valve plug thereby opening a passageway for air from the cartridge chamber to a conduit in the piston setting device by contacting a plunger arranged on the face of the piston setting device with the valve plug and pushing the valve plug in an open position by the plunger, connecting an attachment element arranged on the piston setting device to a vacuum source.
A method for setting a piston in a cartridge according to a further embodiment of the invention comprises the step of attaching a piston setting device to a piston in a fluid tight manner, opening a valve plug in the piston by actuating the valve plug, thereby opening a passageway for air from the cartridge chamber to a conduit in the piston setting device wherein the valve plug is actuated by an interior plunger during the setting process for allowing a vacuum source to extract air between a filling mass disposed in said cartridge chamber and said piston and the interior plunger closes the valve plug after the extraction of air has been completed.
The preferred embodiments are described in more detail in the following with reference to the drawings. Shown are in:
a: a piston according to
b: a variant of a piston and a piston setting device according to a second embodiment of the invention:
c: a detail of
A cartridge 26 comprises a piston 25 which is moveable within a cartridge chamber 27 containing a filling mass 30. The piston 25 from
This second piston part 4 includes a circular cylindrical wall part 5 that engages with the first piston part 1 at the base of the recess 3. The engagement connection is designated with reference numeral 6. The circular cylindrical wall part 5 transitions along an arc into a valve plug 7. This valve plug 7 penetrates a cylindrical hole 11 in the first piston part 1 and has a valve face 9 that contacts the valve lip 10 of the first piston part 1. The arc-like transition region 8 crosses over the cylindrical wall 12 between the hole 11 and the recess 3.
The engagement connection 6 is interrupted by a small air channel 13. A filter section 14 is formed between the outer side of the wall 12 and the inner side of the circular cylindrical wall part 5. This filter section 14 comprises narrow channels in the inner wall of the wall part 5. The filter section 14 can be formed by circular channels, which have interruptions for passage of air between channels. They can also be formed by longitudinal ribs. Preferably, the filter section 14 is formed by threads, in particular helical threads. The channels of the filter section have a thickness of less than a millimeter, preferably less than 0.5 mm, particularly preferred less than 0.1 mm, so that viscous filling masses cannot penetrate through these channels.
The arc-like transition region 8 ensures that the valve plug 7 is pressed against the rear side of the piston. If the piston is inserted into a cartridge chamber by a piston setting device, then the valve plug 7 is moved upwards, whereby the valve formed by the valve face 9 and the valve lip 10 is opened. The air trapped between the filling mass and the piston escapes through the recess 3, the channel 13, and the filter section 14, and is emitted by the valve. If the piston is pushed against the filling mass, then this mass reaches completely throughout the channel 13, but not into the filter section 14. In this way, the filling mass is prevented from reaching the valve. For filling masses that secrete creeping, oil-like components, it is completely possible for these components to penetrate the filter section 14, but their emission is prevented by the venting valve 21.
The first piston part 1 can be at least partially covered by a cover plate having holes on the side facing the filling mass, which is not shown in the FIGS.
According to
The coaxial cartridge 38 has an inner storage chamber 33 which serves for the reception of the first component 31 and an outer chamber 34 which surrounds the inner storage chamber 33 and which serves for the reception of the second component 32. The inner storage chamber 33 and the outer storage chamber 34 are divided from one another by a jacket element 35. The jacket element 35 can in particular be made as an inner tube having a circular cross-section. The outer storage chamber 34 is in turn surrounded by an outer jacket element 36 which can in particular be made as an outer tube with a circular cross-section. The jacket element 35 is received concentrically in the outer jacket element 36. The inner surface of the outer jacket element 36 will be called a cartridge wall 37 in the following.
The first and second flowable components 31, 32 can thus be dispensed from the corresponding inner and outer storage chambers 33, 34 simultaneously by movement of an inner piston 25 and of an annular piston 15.
The coaxial cartridge has an inlet end and outlet end, which is not shown in the FIGS. The first component 31 and the second component 32 exit through the outlet end when they are dispensed from the inner and outer storage chambers 33, 34. Outlet passages, which are closable by a closure element, are provided for this purpose at the outlet end.
A coaxial cartridge is usually filled via the inlet end. For this purpose, the outlet passages are held closed by the closure element, at least toward the end of the filling procedure, to keep the components 31, 32 completely separate from one another. Any air captured between the components 31, 32 and the outlet passages can escape by occasional release of the outlet passages or by the respective valve according to FIG. 1,2 or 7.
Once the filling of the inner storage chamber 33 with the first component 31 and of the outer storage chamber 34 with the second component 32 is completed, the inner storage chamber 33 is closed by the inner piston 25 and the outer storage chamber is closed by the annular piston 15. In this state, the two components 31, 32 are enclosed in the coaxial cartridge such that they are transportable and can be stored at least for a limited period.
a shows a piston 25 according to
The piston setting device 40 for a cartridge comprises a housing 41, a conduit 42 arranged in said housing, said conduit 42 having a first end 43 and a second end 44, said first end 43 comprising a plunger 45, said plunger 45 being connectable to a valve plug 7 of a venting valve 21 of the piston for displacing said valve plug 7 to an open position for allowing air to flow through the conduit 42 and the second end 44 comprising an attachment element 46 connectable to a vacuum source 48. The attachment element 46 can be plugged into the conduit 42. This allows for an easy assembly and disassembly of the attachment element 46. The attachment element 46 can be a conventional hose adapter. Alternatively a thread can be provided in the conduit 42 at the second end 44 thereof for receiving the attachment element 46. Such a thread is shown in
Advantageously a vacuum tube 47 is connected to the attachment element. Such a vacuum tube can be a flexible hose allowing for a displacement of the piston setting device 40 together with the piston.
The first end 43 of the conduit 42 has at least one inlet opening 49, 50, 51 arranged adjacent said plunger 45. Preferably, the first end 43 of the conduit 42 comprises a plurality of inlet openings 49, 50, 51, which is best seen in
Between the piston and the face 53 of the piston setting device 40, a sealing element 52 can be provided.
b shows a piston 25 according to
The interior plunger 150 is according to the embodiment of
It is thus possible to open the passageway to the conduit 42 at any position of the piston setting device 40. The piston setting device 40 can thus operate as a plunger to displace the piston 15, 25 to discharge the filling mass 152 from the respective cartridge chamber 106, 107 as best seen in
The piston of
The piston setting device 40 may belong to a commercial expulsion gun which is not shown in the FIGS. Such a piston setting device is shown in part in
The two-component cartridge has a first filling end 112 and a second filling end 113. A first piston 103 and a second piston 104 can be inserted into the corresponding first and second cartridge chamber 106, 107. The first piston 103 is moveable within the first cartridge chamber 106, the second piston 104 is moveable within the second cartridge chamber 107. Each of the first and second pistons 103, 104 is provided with a sealing element 135, 136 to provide a fluid-tight seal for the filling mass in the cartridge chambers.
The first and second cartridge chambers 106, 107 have different cross-sectional areas due to the fact that the mixing ratio of the first and second components 108, 109 is not necessarily 1:1.
The first piston 103 slides along a first cartridge wall 124 of the first cartridge chamber 106 in direction of the first discharge end 114 if the filling mass present in the first cartridge chamber 106, this being the first component 108 is to be discharged from the first cartridge chamber 106. The second piston 104 slides along a second cartridge wall 125 of the second cartridge chamber 107 in direction of the second discharge end 115 if the filling mass present in the second cartridge chamber 107, this being the second component 109, is to be discharged from the second cartridge chamber 107. The components 108, 109 are shown as transparent filling mass so as to make the structure of the cartridge visible.
The first and second pistons 103, 104 are each movable by a plunger element which is not shown in
The first cartridge chamber 106 and the second cartridge chamber 107 are connected at their first and second discharge ends 114, 115, thereby defining the spatial position of the first cartridge chamber 106 with respect to the second cartridge chamber 107. The first and second discharge ends 114, 115 lead into a corresponding first and second discharge element 118, 119 which contains the corresponding first discharge opening 120 and second discharge opening 121. The first and second cartridge chambers 106 and 107 are located next to each other and the longitudinal axis 126 of the first cartridge chamber 106 is parallel to the longitudinal axis 127 of the second cartridge chamber 107.
In operation, the two component cartridge is filled from the first filling end 112 and the second filling end 113 with the corresponding first and second components 108, 109. The first and second discharge opening 120 and 121 are each closed at least after any air remaining enclosed between the respective filling mass and the discharge opening is vented. After completion of the filling of the first cartridge chamber 106 with the first component 108 and the second cartridge chamber 107 with the second component 109, the first piston 103 is inserted into the first cartridge chamber 106 and the second piston 104 is inserted into the second cartridge chamber 107. The first piston 103 comprises a first valve 122 and the second piston 104 comprises a second valve 123. Each of these first and second valves 122, 123 may be of a similar construction as shown in
The first piston 103 comprises a first piston body 133 which has a first height dimension 144. The second piston 104 comprises a second piston body 134 which has a second height dimension 145. The passage of any air between the piston 103, 104 and the respective cartridge wall 124, 125 is prevented by respective first and second sealing elements 135, 136, which can comprise one or more elastically deformable protrusions.
When the first and second components 108, 109 are discharged from their respective cartridge chambers 106, 107 pressure is applied to the first and second pistons 103, 104 by a plunger element. The pistons 103, 104 are thereby advanced in the direction of the respective first and second discharge element 118, 119. The first and second components 108, 109 are moved into the first discharge opening 120 and the second discharge opening 121. Thereby two separate fluid streams of each of the components 108, 109 are produced which can be applied to the desired application or can be lead into a mixer attached to the first and second discharge elements 118, 119. The mixer can be in particular a static mixer.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5100241 | Chan | Mar 1992 | A |
| 5601107 | Moore et al. | Feb 1997 | A |
| 6257714 | Seccombe | Jul 2001 | B1 |
| 6494348 | Prestele | Dec 2002 | B2 |
| 6598766 | Brugner | Jul 2003 | B1 |
| Number | Date | Country |
|---|---|---|
| 295 06 800 | Aug 1996 | DE |
| 298 00 594 | Mar 1998 | DE |
| 200 10 417 | Oct 2001 | DE |
| Number | Date | Country | |
|---|---|---|---|
| 20110146836 A1 | Jun 2011 | US |
