EP0915743B1 - Device for squeezing flowable material out of a tubular bag - Google Patents

Description

The invention relates to an arrangement for pressing a flowable substance with an elongated tubular bag containing it according to the preamble of claim 1 and claim 5.

It is known to be a flowable, pasty mass such as sealant or dental impression material from a tubular bag squeeze out by introducing it into a cylinder space which is loaded with a piston from one end and one at the other end where the bag is opened Has discharge opening or discharge nozzle. It becomes special Emphasis on the sealing of the bag opening containing end of the tubular bag opposite the emptying opening forming end of the cylinder space and the discharge nozzle. If you tight the tubular bag for this purpose connects with the device forming the cylinder space (FR-A 1 161 905) one makes the multiple use of the squeezing device impossible for several tubular bags. If you do that Tubular bag in one piece or via thread with the dispensing nozzle connects (DE-A 35 00 625), prevented or difficult one the exchange of the tubular bag, if not the nozzle is also designed as a disposable part. The latter is often not possible or undesirable. The arrangement of with special clamping or screw parts to be fixed sealing elements between the end of the tubular bag and the dispensing nozzle or emptying opening (EP-A 319 666) complicates the Exchange. To avoid these disadvantages is the one in the preamble of claim 1 arrangement for squeezing replaceable tubular bags become known (EP-A 541 972), in which the gathered, forming the bag opening End of the tubular bag firmly connected with a sealing ring is that has a conical sealing surface with a corresponding conical sealing surface in the discharge opening of the squeezer. Under the effect of The piston of the sealing ring is pressed into the conical one Emptying opening pressed, provided that it is sufficiently centered beforehand is. If there is insufficient centering, there will be no sealing conditions. If the cone of the sealing ring is exactly centered in the discharge opening sits, it seems possible a sufficient Achieve sealing effect, as long as the effect of Piston force stops. This sealing effect ends when Termination of the piston force the arrangement "breathes". There during of squeezing out most of the pressure drop not in the Bag opening or the discharge opening of the squeezer, but in the downstream rooms of the nozzle and the existing mixing device takes place, builds up during of squeezing in these downstream of the emptying opening Clear up a considerable amount of pressure that is too appropriate Expansion of the associated walls leads. Ends the squeezing force of the piston, this expansion leads to a back pressure and a backflow of the mass in the area of the discharge opening. This allows the cone of the sealing ring to move away from its conical one Be lifted off the seat in the emptying opening; the Sealing gap opens and the mass can be sealed in the Space between the sealing ring and tubular bag on the one hand and Penetrating the cylinder space on the other hand. Also mutual Centering is lost, so that the cone of the sealing ring not in the correct position the next time it is pressed on is returned. Soiling of the device can be caused by the known arrangement cannot be avoided entirely. To comes the disadvantage that the emptying opening when changing the Tubular bag must be cleaned carefully, otherwise Remains of the mass remaining there and possibly solidified a complete seal even while working Make pressing out impossible, which then leads to further contamination of the device. The well-known type of sealing also requires Careful manufacture and assembly of the seal involved parts, which is expensive. It is known (EP-A-663348) to counteract these disadvantages by that the ring bearing the cone has an inside diameter of the cylinder space receiving the tubular bag Has edge diameter and fixed in a circumferential groove that is between the end of the wall of the cylinder space and a lid forming the dispensing nozzle is formed. However this has the disadvantage that the tubular bag only in such devices can be used, the cylinder space contains the mentioned circumferential groove and one on the discharge side for insertion of the tubular bag to be opened lid.

The invention has for its object an arrangement of to provide in the preamble of claim 1 specified type which is less expensive, an easy change of the Tubular bag enables and yet a sufficient seal guaranteed.

The solution according to the invention consists in the features of the claim 1 or 5.

Appropriate developments of the invention are in the respective dependent claims described.

The exclusive action of the sealing elements of the sealing ring on the end face surrounding the emptying opening or on the of this formed edge of the discharge opening makes one Careful cleaning of the less accessible discharge opening dispensable. There is also a cleaning of the face often dispensable because experience shows that the crowd seldom penetrates so far. In the area of the edge are any Ground residues are displaced without affecting the sealing effect. The interacting sealing surfaces make less demands to accurate manufacture and assembly because it is not required is, any diameters exactly on top of each other vote. Finally, the invention has the advantage that the seal is independent of the design the emptying opening and the tubular bag therefore in different Extractors can be used. Also the sealing effect cannot be caused by any misalignment of the sealing ring are impaired.

In general, this is the discharge opening of the squeezer surrounding face flat. Then it is recommended that To form a sealing ring (apart from protruding sealing elements), so that it extends parallel to the end face can. This is especially true if he is after another Feature of the invention an approximately the diameter of the cylinder space has the same outside diameter. This causes good guidance and centering of the tubular bag end when inserted into the discharge opening. It is also advantageous if the edge of the sealing ring is a considerable height has when inserting the tubular bag into the cylinder space from the back of which is remote from the discharge side prevents the sealing ring from tilting. This height is preferably at least 4 mm or 6% (better 10%) of the Diameter. Furthermore, it can be useful if the peripheral surface in whole or in part on one or both Edges are tapered or beveled or rounded to provide that To facilitate introduction into the cylinder space and possibly also to avoid tilting.

To lift the sealing elements from the end face of the cylinder space to avoid the sealing ring after another Feature of the invention with a locking it in the sealing position Be holding part provided. The invention preferred two embodiments of this idea. The first draws is characterized in that the holding part as one with the inner wall cooperating clamp formed the cylinder space is. This is preferably due to the fact that the Washer forming or holding disc is flexible and you Outside diameter a little larger than the inside diameter of the cylinder space. Will the disc during the extrusion of the piston pushed against the end face, so bends itself outward, deforming on the inner surface of the cylinder space adjacent edge a little to the rear, whereby in Longitudinal section of the angle between this edge and the normal on the cylinder wall is so small that self-locking takes place. That means that the disc in the one lent to her Position is held. When the piston force ends it cannot withdraw and the sealing elements remain underneath the elastic force of the disc deformation against the Face pressed. This prevents breathing. In the second embodiment of the holding part Disc with a suction cup that holds it to the face equipped. It can be one or more Act suction cups.

According to another feature of the invention is at the rear end of the tubular bag a braking element arranged, the Holds the bag in the respective position in the cylinder compartment. It also prevents friction during removal and the vertical installation of the cylinder with the outlet opening the bag slides upwards or even slips out the cylinder falls out. The fact that when inserting the Bag in the cylinder space immediately on the pull-in force the braking element arranged at the rear end of the tubular bag is exercised, it does not have to over the bag and its contents are transmitted to the braking element and therefore affects does not look at the inside pressure of the bag.

Fig. 1

einen schematischen Längsschnitt durch eine den Schlauchbeutel enthaltende Kartusche,

Fig. 2 bis 4

Teilschnitte durch den Bodenbereich der Kartusche mit unterschiedlichen Dichtringen,

Fig. 5 und 6

Längsschnitte durch eine weitere Ausführungsform in zwei unterschiedlichen Funktionsstellungen und

Fig. 7

eine Bremsscheibe am hinteren Ende des Schlauchbeutels.

The invention is explained in more detail below with reference to the drawing, which illustrates advantageous exemplary embodiments. Show it:

Fig. 1

2 shows a schematic longitudinal section through a cartridge containing the tubular bag,

2 to 4

Partial cuts through the bottom area of the cartridge with different sealing rings,

5 and 6

Longitudinal sections through a further embodiment in two different functional positions and

Fig. 7

a brake disc at the rear end of the tubular bag.

1 shows the tubular bag 1 within a so-called cartridge 2, which comprises a wall 3 and a bottom 4. Your inside diameter is dimensioned to match that of the tubular bag 1. Cartridges of this type with tubular bags are considered Interchangeable inserts in devices for dispensing plastic masses used, for example in devices for spreading dental multi-component impression materials (EP-A 492 413).

The cartridges are inserted into the device in such a way that a device-owned Piston 5 in the direction of the arrow in the open, far from the ground End 6 of the cartridge can penetrate the tubular bag 1 squeeze. The gathered together in the warehouse closed end 7 of the bag at the other end is cut off so that a bag opening 8 is formed, which in an emptying opening 9 located in the bottom 4 of the cartridge opens. Between the cylinder chamber 10 facing the cartridge Face 11 of the bottom 4 and the shoulder surface 12 of the tubular bag 1, a sealing ring 13 is inserted. If the piston 5 compresses the tubular bag 1, the contained therein through the bag opening 8 and the emptying opening 9 in the downstream, not shown Spaces of the device flow, for example, with another Component to be mixed and finally in the desired way to be applied. The piston in the Tubular bag 1 generated pressure also acts on the shoulder surface 12 on the sealing ring 13, so that this at least during the squeezing process an effective seal between the front surface 11 and the shoulder surface 12 forms. Moreover the gathering 7 against the wall surface of the emptying opening 9 pressed so that a ballast seal is created at this point. The term cylinder space is not intended to mean that the Wall 3 must be cylindrical; however, it is convenient.

In Fig. 1 it is assumed that the bottom 4 of the cartridge is firmly connected to its wall 3 and the tubular bag 1 into the cartridge from the far side is used. However, versions are also possible at which the bottom of the wall 3 like a lid to insert the Tubular bag 1 can be solved.

In the embodiment of the sealing ring shown in FIG this is designed as an annular disc 14. You can with the Shoulder surface 12 of the tubular bag 1 may be glued. you Outside diameter is not much smaller than that the cylinder space 10. When inserting the tubular bag into the cartridge can therefore center the bag opening serve in relation to the discharge opening. it consists of rigid plastic to perform this task. It also expediently has such a high strength that the approximately flat or parallel to the end face 11 position of the Washer 14 can secure.

Near the inner edge of the washer 14 is an O-ring 15 (es can also be several) tight and preferably firm with the Washer 14 connected, for example, in a Ring groove is glued or pinched. It consists of Soft rubber or foam rubber with a closed surface and therefore lies below the one acting during the squeezing process Pressure without gaps on the end face 11 and thus forms effective protection against the penetration of mass of the emptying opening 9 if mass between the gathering 7 and the wall of the discharge opening 9 should pass through. The O-ring 15 has moved so close to the emptying opening 9 that it cooperates with their edge, whereby the Sealing effect is improved.

Since the bag opening 8 due to the lack of one in the discharge opening 9 penetrating ring part clear a larger Diameter can be known as tubular bags, is hers Flow resistance low, so the extent of "breathing" and hence the risk of mass intrusion between the gathering 8 of the tubular bag and the wall of the emptying opening 9 are less than in known arrangements. The washer 14 can, as shown in Fig. 3, with an upright Edge 27 are provided.

With inattentive insertion of the deformed bag 1 in the Cylinder 3 can happen that the end face of the bag is a little skewed. The corresponding inclination the front surface is transferred to the sealing ring if this is designed as a disc or with a disc is connected, the entire surface with the end face of the bag is glued. Among them, in the embodiment according to FIG. 2 suffer from tightness, but not in the versions according to 3 and 4.

Figure 3 shows that the total with the reference number 13 designated sealing ring from a disc 16 and an in a groove of the same secured, rubber-elastic O-ring 15 there is, the sealing with the end face 11 of the cartridge bottom 4 interacts. By an adhesive and sealant 40 the disc 16 is connected to the end face 12 of the bag 1. The connection is limited to the radially inner area the disc 16 and the end face 12 and is outward delimited by a bead 41 which is annular on the Bag 1 facing the face of the disc 16 concentrically is provided for the pane opening and the circumference of the pane. Outside the annular bead 41 are the disk 16 and the bag end face 12 disconnected and usually a little bit apart lifted. Therefore, it is that the disc 16 itself with respect to the bag face 12 in a certain angular range can tilt freely, the bead 41 on the one side more and on the other side less in the Bag. Any misalignment of the bag, as indicated in Figure 2 is therefore not possible on the position of the disc 16 and the sealing effect of the O-ring 15 impact.

In the embodiment according to FIG. 4, the end face 12 of the Bag 1 essentially over the entire surface by means of the adhesive 40 connected to the disc 16 of the sealing ring 13 so that the Washer 16, as indicated in the drawing, on a possible Deformation of the bag due to misalignment takes part. However, this cannot lead to tightness defects, because that Sealing member of the sealing ring 13 from a central projection 45 is formed with a spherical surface 46. The Projection surrounds an opening 47 through which the braid 7 projects, which forms the bag opening 8. The spherical surface 46 forms the sealing surface on the bag side.

The counter sealing surface is formed by the edge 43, which on Bottom 4 of the cartridge at the transition between the end face 11 and the discharge opening 9 is formed. The edge 43 lies in the plane of the surface 11 and is circular. Your diameter is smaller than the outer diameter of the spherical projection 45. Therefore, the edge 43 can on the spherical Sealing surface 46 along a closed circumferential sealing line complete. A similar effect is achieved if the Sealing surface is tapered, provided its taper angle is essential is more blunt than that of a cone, if appropriate Wall 44 of the discharge opening 9.

The curvature diameter of the spherical sealing surface 46 is considerably larger than the diameter of the sealing edge 43, so that a wedging of the spherical sealing surface in the edge 43 or the wall 44 of the opening 9 cannot take place. The Tangent at a point of contact between the spherical Sealing surface 46 and the sealing edge 43 forms with the axis of the Sealing edge 43 an angle 48, which is advantageously larger than 30 °, is more appropriately greater than 40 °. However the angle should be less than 60 ° so that the projection 45 automatically centered relative to the edge 43. Corresponding applies to a conical shape of the projection 45.

This version not only has the advantage of being insensitive towards misalignment of the sealing ring, but leads also a particularly reliable seal, because the Sealing pressure on the edge 43 is high and any contamination be squeezed away.

5 and 6, the bag is 1 provided on the emptying side with a disc 20, which at its the bag opening through the central opening 21 an O-ring 22 carries. The outer diameter of the disc 20 is a little larger than the inside diameter of the cartridge wall 3. When the bag with the disc 20 is advanced in the direction of the arrow is therefore deformed the resilient Disk in such a way that its outer edge is inclined supports against the cartridge wall 3. This inclined position of the edge 23 opposite the cartridge wall 3 then remains when the disc reaches its end position (Fig. 6). If the piston pressure ends, the disc 20 cannot be without recede further because between its edge 23 and the Inner surface of the cartridge wall 3 has a self-locking friction ratio consists. The seal 22 therefore remains below the elastic Force of the disk 20 pressed against the end face 11. In principle, this also applies if the Self-locking effect on the edge 23 of the disc is dispensed with and just some kind of friction between the Edge 23 and the cartridge wall 3 is provided, its resistance is at least of the same order of magnitude as that when breathing on the face of the bag due to back pressure Acting force.

Fig. 7 shows the arrangement with one at the rear end of the Hose bag attached brake element. At the end of the tubular bag 1 is placed on this a disc 30, which in in the middle is an opening for receiving the closure strand 31 of the bag contains. Their circumference has a rubbing effect on the inner surface the cartridge 2 together. When inserting the Tubular bag into the cartridge in the direction of the arrow from the The insertion force on the bag is at the far end transmitted via the disk 30. The friction force on the circumference of the Disc 30 therefore does not affect the internal pressure of the bag 1 off. If the cartridge with the bag contained therein stored outside the application device and with the end 6 placed vertically downwards, the frictional force increases Circumference of the disc 30 the weight of the filled bag 1 and keep it in the existing position.

The circumference of the disk 30 can be provided with devices be the friction force even in the presence of certain dimensional tolerances the disc 30 and the cartridge 2 in a desired one Hold area, for example with a friction-increasing Elastomer ring.

In many cases, one will prefer a version that is the backward movement of the bag desired a frictional force Opposing the height, pushing the bag into the cartridge from the rear end there is less resistance offers. For example, versions are suitable for this, where the level 33 in which the line of contact between the scope of the disc 30 serving as a braking element and the inner surface of the cartridge 2 is offset to the rear is opposite to the main plane 34 of the disc. With axial movement the disk creates the friction on its circumference Bending moment that enters the contact area into the cartridge directed movement with reduced friction radially inside and with the opposite direction of movement under appropriate Increasing friction pushes radially outwards.

The adjacent to the inner wall of the cartridge 2 Disk 30 need not be continuous; rather can it should be interrupted so that a plurality of flexible arms is formed, the ends of which resiliently on the cartridge wall and only connected to each other in the central area are.

The axial offset between the contact plane 33 and the Main plane 34 of disk 30 or its arms need not to be predetermined by their original form; much more the part can also be designed flat and only by elastic Deformation when inserted into the cartridge the outside take a curved shape.

Claims (15)

1. An arrangement for extruding a flowable substance, having an elongate tubular pouch (1) containing it, which pouch has at at least one end an opening (8) surrounded by a shoulder (12) of the tubular pouch (1) and by a sealing ring (13) connected therewith and having or forming at least one sealing member (15,22,45), and having an extrusion device (2,5) comprising a cylindrical chamber (10) which accommodates the tubular pouch and which at one end accommodates a plunger (5) and at the other end includes a discharge opening (9) co-operating with the pouch opening (8), which discharge opening is surrounded by an end face (11) opposite the shoulder (12) of the tubular pouch (1) and the sealing ring (13), characterised in that the sealing member (15,22,45) of the sealing ring co-operates exclusively with the end face (11) surrounding the discharge opening (9), namely with the edge of the discharge opening formed by this end face (11).
2. An arrangement according to Claim 1, characterised in that the sealing ring (13) is connected to the pouch (1) and is angularly movably in relation to the pouch axis (42).
3. An arrangement according to Claim 2, characterised in that the sealing ring (13) is connected to a disc (16) or is in the form of a disc which is bonded to the pouch end face (12) inside an annular bead (41) facing the latter, the diameter of which annular bead is substantially smaller than that of the pouch (1).
4. An arrangement according to Claim 1, characterised in that the sealing surface (46) of the sealing member (45) is spherically or conically formed and the angle (48) between the tangent applied at the point of contact and the centre line (42) is substantially larger than the angle between the direction of the wall (44) of the discharge opening (9) and the centre line (42).
5. An arrangement for extruding a flowable substance, which has an elongate tubular pouch (1) containing the substance, which pouch has at at least one end an opening (8) surrounded by an end face (12) of the tubular pouch (1) and by a sealing ring (13) connected thereto and having or forming at least one sealing member (45), and comprises an extrusion device (2,5) which comprises a cylindrical chamber (10) which accommodates the tubular pouch and which at one end accommodates a plunger (5) and at the other end includes a discharge opening (9) co-operating with the pouch opening (8) and having a sealing surface (43) co-operating with the surface of the sealing ring (13), characterised in that the sealing surface (46) formed by the sealing ring (13) and/or the sealing surface provided at the discharge opening (9) is spherically formed.
6. An arrangement according to any one of Claims 1 to 5, characterised in that the angle (48) between the tangent at the point of contact of the sealing surfaces (43,46) and the centre line (42) is larger than 30°.
7. An arrangement according to any one of Claims 1 to 6, characterised in that to centre the pouch opening (8) relative to the discharge opening (9) the outer diameter of the sealing ring (13) in the form of an annular disc is not substantially smaller than that of the cylindrical chamber (10).
8. An arrangement according to any one of Claims 1 to 7, characterised in that the peripheral surface (28) of the sealing ring (13) has a height of at least 4 mm or 6 % of the sealing ring diameter.
9. An arrangement according to any one of Claims 1 to 8, characterised in that the sealing ring is provided with at least one retaining member locating it in the sealing position.
10. An arrangement according to Claim 9, characterised in that the retaining member is in the form of a clip (23) co-operating with the inner wall of the cylindrical chamber.
11. An arrangement according to Claim 10, characterised in that the retaining member is in the form of at least one suction clamp co-operating with the end face (11).
12. An arrangement according to any one of Claims 1 to 11, characterised in that a retarding member (30) is provided at the end of the pouch (1) opposite the end containing the. opening (8), which retarding member co-operates frictionally with the wall (3) of the cylindrical chamber (10) at least in the direction in which the pouch (1) extends out of the cylindrical chamber (10).
13. An arrangement according to Claim 12, characterised in that the retarding member (30) comprises a disc or a ring by way of which the plunger (5) acts on the tubular pouch.
14. An arrangement according to Claim 12 or 13, characterised in that the optionally interrupted periphery of the retarding member (30) is of a diameter which is larger than the internal diameter of the cylindrical chamber (10).
15. An arrangement according to any one of Claims 12 to 14, characterised in that the plane (33) of contact between the retarding member (30) and the wall (3) of the cylindrical chamber (1) is displaced in relation to the plane (34) of the region of the retarding member abutting the tubular pouch (1) in the direction away from the tubular pouch (1).

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