Valve disk and container produced therewith

Abstract

The valve disk is intended for use with containers that are subjected to gas pressure, for example, self-cooling beverage cans and spray cans. The valve disk has an annular recess (14), which is radially delimited on the exterior by a circumferential wall (16) with a fastening edge and which is radially delimited on the interior by a downwardly enlarging dome (18) provided with an opening (20). A valve can be inserted into said dome. In order to enable higher internal pressures' of the container, the invention provides that the wall of the dome (18) is provided, in the enlarging area (22), with beads (30) that are arranged in the circumferential direction of the wall of the dome (18) in an interspaced manner.

Description

[0001] The invention relates to a valve plate for containers acted upon by gas pressure, such as self-chilling beverage cans and spray cans, having an annular indentation which is defined radially outward by a circumferential wall with a fastening edge and radially inward by a dome provided axially outward with an opening, into which dome a valve can be inserted and which dome is adjoining a region that widens radially axially inward, and to a container produced with such a valve plate.

[0002] The container can for instance be an aerosol package or in general a container such as a can of tinplate or an aluminum alloy that is subjected to gas pressure in order to expel the product and optionally spray it when the valve is actuated. Most spray cans have an opening on the face end with a diameter of about 25.4 mm (one inch), which by means of clinching can be tightly closed by a valve plate with a fastening edge, optionally using an external seal. In the dome of the valve plate that meets DIN standard 55501, a valve will have been inserted beforehand, normally using an internal seal, by crimping, and a hollow valve tappet protrudes to the outside from it. Depressing the valve tappet opens the valve and expels the contents of the container as a result of the internal gas pressure. In most cases, filling the container with the gas and with the composition to be expelled is also done through the valve. However, double-walled containers with a flexible inner wall also exist, in which the compressed gas is introduced via a separate, closable container opening into the space between the walls (see European Patent Disclosure EP 0 718 213 B1 and U.S. Pat. No. 4,175,678). In all these cases, if the containers are improperly stored in an overly warm environment, or even from sunshine, very high internal pressures of up to about 50 bar can occur. Especially beverage cans, for certain beverages such as beer, which are to be sterilized by heating to make them capable of storage, must be heated after being filled to approximately 65° C. In beverage cans with a built-in cooling system, in which the chilling that is wanted immediately before the beverage is drunk is attained by depressurization of what until then has been a maintained high pressure, is achieved in a separate internal container whose bottom is formed by a valve plate (see the journal Spray Technology & Marketing, July 2000, pp. 30, 31 and 40, 41), a pressure resistance of up to 56 bar for the internal container is required for safety reasons.

[0003] The problem of occasionally very high internal pressures has been known for decades. Until now, valve plate manufacturers in accordance with DIN 55501 have tried to solve it with a suitable sheet-metal thickness, for instance of 0.4 or 0.5 mm, instead of 0.3 mm. The object of the invention is to develop a shape of the valve plate that allows substantially higher internal pressures than conventional valve plates of the same sheet-metal thickness.

[0004] The present object is attained according to the invention in that in a valve plate of the type defined at the outset, the widening region is provided with beads, extending in the circumferential direction with spacing between them, which extend essentially radially across the widening region.

[0005] Surprisingly, it has been found that with such a design of the valve plate, although it is not uniform over the circumference, a markedly improved stability to elevated internal pressures can be achieved.

[0006] In the preferred embodiment, the provision according to the invention is combined with a comparatively small angle of at maximum about 45°, and preferably even only at most 35°, that the widening region forms in axial section with the central longitudinal axis of the valve plate. For an essentially cylindrical circumferential wall, this leads to a greater height of the valve plate, but there is still material compensation in comparison to valve plates of conventional shape, in which the same high shape stability is achieved by increasing the sheet-metal thickness. In certain cases, the object of the invention can even be attained if only the angle of the widening region is reduced to the aforementioned maximum value, so that the beads are not additionally needed. In this way as well, sheet-metal thicknesses not required for other reasons, which necessitate high clinching that can cause deformation and leaking of the can opening, can be avoided. The aforementioned angular dimensions also refer to the mean value of the wall inclination, if in axial cross section a curved shape of the widening region in axial section that deviates from that of a truncated cone is taken into account.

[0007] The greater height of the valve plate, which reduces the available internal space in the container, can in a further preferred embodiment of the invention be partly compensated for if the proposed beads are made to bulge radially outward. In the shape intended for the practical embodiment, six beads distributed uniformly over the circumference in a star pattern, each extending over an angular range of approximately 20 to 25°, are provided. They preferably have a depth of approximately 0.4 to 1.8 mm. Their side edges are located on radial rays, and each bead extends radially essentially across the entire widening region.

[0008] In a first alternative embodiment, the beads, in a cross section along a circumferential arc, are shaped in stepped fashion at their edges and over their surface are shaped with a uniform depth. Alternatively, they can also be increasingly indented toward their center.

[0009] Since the advantageous properties of the novel valve plate are displayed in the finished package, the invention also relates to a container as defined by claim 12.

[0010] Several exemplary embodiments of the invention are described in further detail below in conjunction with the drawing. There are shown in:

[0011] FIG. 1, a plan view on a first embodiment of a valve plate of the invention;

[0012] FIG. 2, a cross section taken along the line A-A in FIG. 1;

[0013] FIG. 3, a detail at X in FIG. 2, on a larger scale;

[0014] FIG. 4, a detail at Y in FIG. 2, on a larger scale;

[0015] FIG. 5, a first variant of a cross section taken along the line B-B in FIG. 1;

[0016] FIG. 6, a second variant in a cross section corresponding to FIG. 5;

[0017] FIG. 7, a plan view corresponding to FIG. 1 on a second embodiment of the valve plate of the invention;

[0018] FIG. 8, a cross section taken along the line A-A in FIG. 7;

[0019] FIG. 9, a half cross section corresponding to the views in FIGS. 2 and 8, for a third embodiment; and

[0020] FIG. 10, a view corresponding to FIG. 9, for a fourth embodiment of the valve plate of the invention.

[0021] The valve plate shown in FIGS. 1-5, in this example, comprises tinplate 10 that is 0.28 mm thick, with a plastic coating 12, for instance of polypropylene, that is 0.2 mm thick. The valve plate has an annular indentation 14, which is defined radially outward by a cylindrical circumferential wall 16 and radially inward by a dome 18. Adjoining the cylindrical dome, which is provided with an opening 20 in its upper end wall, is a lower region 22, which widens conically downward and at its lower end merges in rounded fashion with the cylindrical circumferential wall 16. On its upper end, the circumferential wall 16 is curved radially outward and provided with a bent-over edge 24 as shown in FIG. 3, of the kind required for tight closure at the opening edge of a beverage can with a cooling system.

[0022] The outside diameter of the circumferential wall 16 is 25.2 mm, for instance, and the inside diameter of the upper region of the dome 18 is 11.8 mm. This region is intended to receive a valve which by means of a seal closes the opening 20 and which is fixed in the dome 18 in a known manner by crimping. The structure of the valve is known and is not the subject of the application. In the fully installed state, a hollow valve tappet protrudes outward through the opening 20, and its edge 26 is shown on a larger scale in FIG. 4.

[0023] The valve plate has a height of approximately 18.2 mm. The cylindrical dome is approximately 6.8 mm high. The region 22 that widens conically downward forms an angle of 33° in cross section with the circumferential wall 16 and with the central longitudinal axis 28 of the valve plate. The outer radius of the rounded transition between the circumferential wall 16 and the conical region 22 is approximately 1.2 or 1.3 mm. The upper end face of the dome 18 is approximately 3.7 mm below the upper edge of the valve plate.

[0024] If the valve plate of FIGS. 1 and 2 is compared with the shape called C in DIN 55501, it can be seen that not only because of the use in a self-chilling beverage can is the outer edge shown in FIG. 3 different, but the height is also more than twice as great as the minimum height of 8 mm specified in that standard. The great height is due to the relatively small cone angle of the conical region 22 and its immediate transition of small radius with the circumferential wall 16. The total height and the height of the conical region 22 can be reduced, if the lower region of the circumferential wall 16 is designed as conical to the inside.

[0025] The steep cone of a conical region 22 already enhances the shape stability of the valve plate to elevated internal pressures in the container closed with the valve plate. A further substantial improvement in the pressure resistance is achieved by providing the region 22 with six beads 30, in this example, that are distributed uniformly over the circumference in a star pattern and with spacing between them in the circumferential direction. Their side edges are located on radial rays, and they extend essentially over the entire height of the conical wall region 22. In width, the beads extend in the circumferential direction over approximately 24°. They are made to bulge radially outward and can for instance have the cross section shown in FIG. 5, with a steplike shoulder at the peripheral edges and a constant depth, or the cross section shown in FIG. 6, with continuous rounding and with the greatest depth in the middle. The depth, or in other words the inward bulge on one side or the outward bulge on the other, amounts in this example to approximately 0.7 mm, but it can also be less, or can for instance be more than twice as great.

[0026] The exemplary embodiment of FIGS. 7 and 8 differs from that of FIGS. 1-4 only in that the beads 30 are lengthened to extend into the rounded portions at the upper and lower ends of the conical wall region 22. As in the exemplary embodiment described above, here as well a lesser or greater number of beads 30 may be present, and their side edges can also have a course that deviates from the radial rays. In another variant embodiment, the region 22 is shaped not as a truncated cone but rather as a truncated pyramid with a polygonal cross section, and the beads can be located then in the flat wall regions.

[0027] The further exemplary embodiments of FIGS. 9 and 10 show that the concept of the invention can be realized independently of how the fastening edge 24 is embodied. The shape of the edge can be adapted to the shape of the edge of the opening to be closed and to how the two edges are joined together. The embodiment of the edge of FIG. 10 meets the specifications of DIN 55501, for instance. Except for the different fastening edges, the valve plates of FIGS. 9 and 10 can have the same shape as the valve plates described above.

Claims

1. (Original) A valve plate for containers acted upon by gas pressure, such as self-chilling beverage cans and spray cans, having an annular indentation (14) which is defined radially outward by a circumferential wall (16) with a fastening edge (24) and radially inward by a dome (18) provided axially outward with an opening, into which dome a valve can be inserted and which dome is adjoining a region that widens radially axially inward, characterized in that the widening region (22) is provided with beads (30), extending in the circumferential direction with spacing between them, which extend essentially radially across the widening region (22).

2. (Original) A valve plate for containers acted upon by gas pressure, such as self-chilling beverage cans and spray cans, having an annular indentation (14) which is defined radially outward by a circumferential wall (16) with a fastening edge (24) and radially inward by a dome (18) provided axially outward with an opening, into which dome a valve can be inserted and which dome is adjoining a region (22) that widens radially axially inward, characterized in that the widening region (22) in axial section forms a mean angle of at most 450 and preferably at most 350 with the central longitudinal axis (28) of the valve plate.

3. (Original) The valve plate of claim 1, characterized in that the widening region (22) in axial section between the beads (30) forms a mean angle of at most 45° and preferably at most 35° with the central longitudinal axis (28) of the valve plate.

4.(Currently Amended) The valve plate of one of claims 1-3,characterized in that the widening region (22), optionally except for the beads (30), has a conical shape.

5. (Currently Amended) The valve plate of one of claims 1-4, characterized in that it comprises tinplate or stainless steel with a material thickness of approximately 0.25 to 0.35 mm, with or without a plastic coating, and the transition between the circumferential wall (16) and the widening region (22) in cross section is formed by an inner radius of at most 1.0 to 1.3 mm, in accordance with the material thickness.

6. (Currently Amended) The valve plate of one of claims 1 and 3-5, characterized in that the beads (30) bulge radially outward and have a depth of approximately 0.4 to 1.8 mm.

7.(Currently Amended) The valve plate of one of claims 1 and 3-6, characterized in that the beads (30), in a cross section located on a circumferential arc, are shaped in stepped fashion at their edges and over their surface are shaped with a uniform depth.

8. (Currently Amended) The valve plate of one of claims 1 and 3-6, characterized in that the beads (30) are increasingly indented toward their middle in a cross section located on a circumferential arc.

9. (Currently Amended) The valve plate of one of claims 1 and 3-8, characterized in that the side edges of the beads (30) are located on radial rays.

10. (Currently Amended) The valve plate of one of claims 1 and 3-9, characterized in that each bead (30) extends radially essentially across the entire widening region (22).

11. (Currently Amended) The valve plate of one of claims 1-10, characterized in that by deformation of the dome (18), it is tightly joined to a valve inserted into the dome.

12. (Currently Amended) An empty or filled container having a valve plate of one of claims 1-11.

13. (New) The valve plate of claim 2,characterized in that the widening region (22), optionally except for the beads (30), has a conical shape.

14. (New) The valve plate of claim 2, characterized in that it comprises tinplate or stainless steel with a material thickness of approximately 0.25 to 0.35 mm, with or without a plastic coating, and the transition between the circumferential wall (16) and the widening region (22) in cross section is formed by an inner radius of at most 1.0 to 1.3 mm, in accordance with the material thickness.

15. (New) The valve plate of claim 4, characterized in that the beads (30) bulge radially outward and have a depth of approximately 0.4 to 1.8 mm.

16.(New) The valve plate of claim 4, characterized in that the beads (30), in a cross section located on a circumferential arc, are shaped in stepped fashion at their edges and over their surface are shaped with a uniform depth.

17. (New) The valve plate of claim 4, characterized in that the beads (30) are increasingly indented toward their middle in a cross section located on a circumferential arc.

18. (New) The valve plate of claim 4, characterized in that the side edges of the beads (30) are located on radial rays.

19. (New) The valve plate of claim 4, characterized in that each bead (30) extends radially essentially across the entire widening region (22).

20. (New) The valve plate of claim 2, characterized in that by deformation of the dome (18), it is tightly joined to a valve inserted into the dome.