APPARATUS FOR DISPENSING A MEDIUM AND METHOD FOR FRONT FILLING THE APPARATUS

Abstract

An apparatus for dispensing a medium includes a cartridge in which a piston is movably receivable. An outlet is arranged in an outlet face of the cartridge for conveying the medium into a storage chamber of the cartridge. The piston includes a conveying side, a drive side disposed opposite the conveying side and at least one seal arranged at a side wall of the piston for providing a fluid-tight sealing between the piston and an inner cartridge wall. The cartridge includes a protrusion or a recess. The protrusion or the recess and the piston are arranged such that they can engage in such a way that, when the piston is arranged in a filling position, substantially no gas can be trapped between the outlet face, the conveying side of the piston and the seal facing the outlet face.

Claims

1. Apparatus for dispensing a medium comprising: a piston; and a cartridge configured to movably receive the piston, and including an outlet arranged in an outlet face of the cartridge, the outlet configured to convey the medium into a storage chamber of the cartridge or configured to dispense the medium from the storage chamber, the outlet face being disposed at an end of the cartridge, the piston comprising a conveying side, a drive side disposed opposite the conveying side and at least one seal arranged at a side wall of the piston, and configured to provide a fluid-tight seal between the piston and an inner cartridge wall, the cartridge comprising at least one protrusion or at least one recess disposed adjacent to the outlet, the protrusion or the recess and the piston being arranged so as to engage such that, when the piston is arranged in a filling position, substantially no gas is trapped between the outlet face, the conveying side of the piston and the seal facing the outlet face.

2. The apparatus according to claim 1, wherein the outlet face has an outlet face surface facing the conveying side of the piston, the outlet face surface being at least substantially planar in a region between the outlet and the least one protrusion or in a region between the outlet and the at least one recess.

3. The apparatus according to claim 2, wherein a conveying side surface of the conveying side is at least substantially planar in a region facing the region of the outlet face surface that is at least substantially planar.

4. The apparatus according to claim 1, wherein the cartridge and the outlet face are integrally formed.

5. The apparatus according to claim 1, wherein a residual volume between the outlet face, the front face and the seal facing the outlet face is substantially filled by the protrusion, when the piston is arranged in the filling position at intended use.

6. The apparatus according to claim 1, wherein the at least one seal can engage the at least one recess such that substantially no gas can be trapped in the recess when the piston is arranged in the filling position at intended use.

7. The apparatus according to claim 1, wherein the piston is capable of being positioned in the filling position with a force sufficient to overcome frictional forces when moving the piston in the cartridge.

8. The apparatus according to claim 1, wherein the piston comprises no venting mechanism for the trapped gas.

9. The apparatus according to claim 1, wherein at least the section of the piston facing towards the outlet face is substantially rigid.

10. The apparatus according to claim 1, wherein the protrusion is disposed on the outlet face and is substantially facing away from the outlet face, such that the protrusion is capable of engaging a piston-recess formed between the side wall and the seal.

11. The apparatus according to claim 1, wherein the cartridge and the at least one protrusion are formed in one piece.

12. The apparatus according to claim 1, wherein the protrusion is in at least a section tapered in direction away from outlet face in at least one cross-sectional view along a longitudinal axis of the cartridge.

13. The apparatus according to claim 1, wherein the protrusion tapers from the outlet face away from the inner cartridge wall towards a longitudinal axis, when viewed along the longitudinal axis A of the cartridge.

14. The apparatus according to claim 1, wherein the recess tapers from the outlet face towards the inner cartridge wall when viewed along a longitudinal axis of the cartridge.

15. The apparatus according to claim 1, wherein the at least one protrusion or at least one recess is at least one continuous protrusion or at least one continuous recess extending around a periphery of the outlet face.

16. The apparatus according to claim 1, wherein the cartridge comprises an insert end with an insert opening for inserting the piston into and removing the piston from the cartridge.

17. The apparatus according to claim 16, wherein the cartridge comprises a blocking element configured to prevent movement of the piston past the blocking element towards the insert opening.

18. The apparatus according to claim 17, wherein the blocking element is formed such that the piston is capable of being moved past the blocking element towards the outlet face.

19. The apparatus according to claim 17, wherein the cartridge is produced with an injection molding process.

20. The apparatus according to claim 1, wherein the piston and the at least one seal are formed in one piece.

21. The apparatus according to claim 1, wherein the cartridge is filled with substances selected from impression materials, adhesives, bonding materials, materials for chemical anchorings or protective coatings materials.

22. A method for front filling an apparatus, with a medium, comprising: providing the apparatus comprising a cartridge configured to movably receive a piston, and including an outlet arranged in an outlet face of the cartridge, the outlet configured to convey the medium into a storage chamber of the cartridge or configured to dispense the medium from the storage chamber, the piston comprising a conveying side, a drive side disposed opposite the conveying side and at least one seal arranged at a side wall, and configured to provide a fluid-tight seal between the piston and an inner cartridge wall, the cartridge comprising at least one protrusion or at least one recess, the piston being arranged in a filling position and the protrusion or the recess and the piston being arranged so as to engage such that substantially no gas is trapped between the outlet face, a front face of the piston and the seal facing the outlet face; conveying the medium into the cartridge through the outlet; moving the piston away from the outlet face with the medium conveyed into the cartridge until at least one of a predetermined amount of medium is conveyed and the piston is positioned at a blocking element of the cartridge.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Referring now to the attached drawings which form a part of this original disclosure.

[0054] FIG. 1 is a schematic view of an apparatus for dispensing a medium according to the present invention with a piston in a filled position;

[0055] FIG. 2 is a schematic view of an apparatus according to FIG. 1 with the piston in a filling position;

[0056] FIG. 3 is a schematic overview of an apparatus for dispensing a medium according to an alternative embodiment of the present invention with a piston in an intermediate position.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] FIG. 1 shows an apparatus 1 for dispensing a medium 18. The apparatus 1 comprises a cartridge 2, in which a piston 3 is arranged. The piston 3 is movable substantially along a longitudinal axis A of the cartridge 2. The cartridge 2 is formed cylinder-like at least in the section in which the piston 3 is movably receivable.

[0058] The cartridge 2 has an insert opening 5 for inserting the piston 3 into the cartridge. A blocking means (or element) 13 is arranged in the cartridge 2 at an inner cartridge wall 11 such that the piston can be inserted into the cartridge 2 and moved past the blocking element 13 towards an outlet face 6 of the cartridge 2. For this, the blocking element 13 is formed such that it is (they are) flexible and e.g. formed as a, in particular, circumferential lip, which is tilted towards the outlet face 6. Due to this arrangement, the movement of the piston 3 past the blocking element 13 towards the insert opening 5 can be prevented at intended use.

[0059] The cartridge 2 and the outlet face 6 are integrally formed at an end of the cartridge, with the outlet face 6 being disposed and formed at least substantially perpendicular to the inner cartridge wall 11.

[0060] A protrusion 9 is arranged on the outlet face 6 of the cartridge 2. The protrusion is arranged in a circumferential manner and faces away from the outlet face 6 and is tapered in a direction away from outlet face 6 along the longitudinal axis A of the cartridge 2.

[0061] The cartridge 2 has a storage chamber 17 for receiving the medium 18 to be dispensed. The size of the storage chamber 17 depends on the position of the piston 3. The shaded area is filled with medium 18.

[0062] The piston 3 has a drive side 15 and a conveying side 10. For dispensing the medium, a pressure is applied to the drive side 15 either in a manual or motorized manner. The piston 3 further has a seal 7, which is formed as a lip seal; the lip can be deflected in a flexible manner to ensure a fluid-tight sealing. The seal 7 is arranged at a side wall 8 of the piston in a circumferential manner for providing a fluid-tight sealing between the piston 3 and the inner cartridge wall 11, such that no medium can pass along the side wall 8 of the piston 3 from the conveying side 10 to the drive side 15.

[0063] The piston 3 has a piston-recess 12 formed between the side wall 8 and the seal 7. For an improved sealing, the piston 3 has a further seal 14, which is also formed as a lip seal.

[0064] According to FIG. 1, the piston 3 is arranged in the filled position S, which represents the position of the piston 3 farthest away from the outlet face 6. Hence, the size of the storage chamber 17 is maximized for receiving the medium 18.

[0065] When a force is applied to the piston 3 in a direction towards the outlet face 6, medium 18 is dispensed from the cartridge 2 through an outlet 4 arranged in the outlet face 6. The dispensing process can continue until the piston 3 comes into contact with the outlet face 6.

[0066] As also shown in FIG. 1 the outlet face 6 has an outlet face surface 20 facing a conveying side surface 22 of the conveying side 10 of the piston. The outlet face surface 20 is at least substantially planar in a region between the outlet 4 and the protrusion 9. Likewise the conveying side surface 22 of the piston is at least substantially planar in a region facing the at least substantially planar outlet face surface 20.

[0067] The protrusion 9 tapers from the outlet face 6 away from the inner cartridge wall 11 towards the longituindal axis A, when viewed along the longitudinal axis A of the cartridge. FIG. 2 shows the apparatus 1 for dispensing the medium according to FIG. 1 in a filling position F of the piston 3.

[0068] Parts denominated with the same reference numeral relate to the same feature in all the figures and are only explained again when needed.

[0069] The apparatus 1 according to FIG. 2 represents the arrangement of the piston 3 before the filling of the cartridge 2. After the filling, the position of the piston 3 is as shown in FIG. 1.

[0070] Before the start of the filling process, the piston 3 is arranged in the filling position F. The protrusion 9 engages the piston-recess 12 formed between the side wall 8 and the seal 7. The protrusion 9 is formed such that substantially no air is trapped between the outlet face 6, the conveying side 10 of the piston 3 and the side of the seal 7 facing the outlet face 6.

[0071] For the filling process, medium 18 is conveyed into the cartridge 2 and a force is applied to the drive side 15 of the piston 3, such that the piston 3 is pushed back towards the blocking element 13 by the medium 18 conveyed into the cartridge in a controlled manner.

[0072] The medium 18 is conveyed into the cartridge 2 through outlet 4 in the conveying direction C.

[0073] Due to the fact that substantially no residual volume for air to be trapped remains in the filling position F between the outlet face 6, the conveying side 10 of the piston 3 and the side of the seal 7 facing the outlet face 6, it is possible to omit the arrangement of a venting mechanism on and/or in the piston 3. Furthermore, it is also not necessary to apply a vacuum to the cartridge 2 before the filling process.

[0074] The piston 3 with the seal 7 and further seal 14 are formed in one piece. The cartridge 2 with the protrusion 9 is also formed in one piece. Both the piston 3 and the cartridge 2 are produce by injection molding. The cartridge 2 and piston 3 are made from a plastic material.

[0075] FIG. 3 shows an alternative embodiment of an apparatus 1 according to the invention in a schematic view.

[0076] The piston 3 is at an intermediate position I between a filling position and a filled position.

[0077] The piston 3 has a lip seal 7 that is positioned at the side wall 8 in a different manner compared to FIGS. 1 and 2.

[0078] To accommodate the lip seal according to FIG. 3, the cartridge has a recess 16, which is arranged in a circumferential manner. In the filling position, the seal 7 and the recess 16 can engage such that no air is trapped between the outlet face 6, the conveying side 10 of the piston 3 and the side of the seal 7 facing the outlet face 6.

[0079] The recess 16 tapers from the outlet face 6 towards the inner cartridge wall 11 when viewed along the longitudinal axis A of the cartridge.

[0080] The outlet face surface 20 of the piston 3 of FIG. 3 is at least substantially planar in a region between the outlet 4 and recess 16. The conveying side surface 22 of the piston 3 is planar in a region facing the planar outlet face surface 20.