Lid ring for allowing flange tilting and method for preparing and forming a lid

Abstract

 The invention concerns a method for preparing or using or forming a lid. The lid or lid ring is concerned as well. The lid (1) comprises a lid ring and a lid foil or membrane, which work together and are coupled together by a sealing portion which seals in ring-like fashion the membrane as panel to a flange of the preferably metallic ring. The suggested lid ring (2) having a first and second attaching portion as radially inner and radially outer portions and an intermediate linking portion, connecting first and second portions, The first portion having a ring surface adapted to carry a sealed foil (3) as panel, said foil having an outer ring band(3b) for sealing on the ring surface (2b). Said outer portion (2a) adapted to be seamed to an edge of a container body. The linking portion provided and configured as circumferential hinge (30). The first and second portions being tiltable relative to each other upon pressure applied to the sealed foil as panel, sealed on the ring surface of the first portion. A change of slope (inclination) of the first portion of the ring happens during retorting, reforming after retort or use of the lid ring with the foil as panel sealed thereto.

Description

[0001] The invention concerns a method for preparing or using or forming a lid. The lid or lid ring is concerned as well. The lid comprises a lid ring (Deckelring) and a lid foil (membrane), which work together and are coupled together by a sealing portion which seals in ring-like fashion the membrane as panel to a flange of the preferably metallic ring. The metallic ring is outside formed to have a seaming edge (seamable outer portion) which is provided and shaped to be seamed by a multiple seam to a body flange of a body wall to cover the body with the ring and the foil, in other words to cover the body with the lid.

[0002] Lid rings of metallic nature and lid foils of metallic, plastic or a combinatorial nature are known in several sorts and shapes. The flat ring flange onto which the foil is sealed (where the lid foil is sealed) has several different orientations. It can be horizontally oriented, it can be tilted upwards, and it can also be tilted downwards. It can even change its shape during sterilization of a closed container, where inner pressure supplies force in axial direction to act on the foil, transferred to the sealing portion and to the panel (ring flange). Different orientations can therefore be present, as well as different orientations can be selected for the foil covering the inner opening, which it covers before, during and/or after a sterilization process, cf. WO-A 2007/088212 (Impress), WO-A 2005/005277 (Crown), and WO-A 2007/45385 (Alcan). All these variants operate with foils that have different shapes during a sterilization process. The sterilization process provides high pressure and high temperature to make the food inside the container stable for longer storage and transport, and during this sterilization of up to 130°C, a pressure has to be resisted by the lid.

[0003] After such sterilization process, the lid has a task to provide long-time shelf- or self-life, until a user wishes to open this lid. At this very time instant, the opening forces have to be very low, as contrary to those forces the lid and the foil have to withstand during sterilization processes. Not all processes in sterilizing do have counter-pressure, as many processes operate with continuous retort systems.

[0004] In this field, it is a task (problem to solve) of the invention as claimed to provide a lid that has superior properties.

[0005] Suggested is a lid ring for closure, said ring having a first and second attaching portion as a radially outer and a radially inner portion and an intermediate linking portion, connecting first and second portion. The first portion has a ring surface adapted to carry a sealed foil or panel, said foil having an outer ring band for sealing on the ring surface. The outer portion is adapted to be seamed to an edge of a container body.

[0006] The linking portion provided and configured as a circumferential hinge, whereby the first and second portions being tiltable relative to each other upon pressure applied to the sealed foil as panel, sealed on the ring surface of the first portion.

[0007] A change of slope (inclination) of the first portion of the ring occurs during retorting, or during reforming after retort or during use of the lid ring with the foil as panel sealed thereto.

[0008] The lid ring with the sealed foil is the lid for closure (claim 14).

[0009] Preferably the intermediate portion is provided with a circumferential score line, for allowing the slope change of the first portion under pressure. The slope change being a free forming under surface pressure onto the foil.

[0010] Preferably the lid ring's flat panel (radial inner portion) has a slope change between (or within) ± 30°, more preferably ± 26°, or ± 20°. The slope change can also be positive only, between 0° to 20°.

[0011] The slope of the lid ring flat panel (radial inner portion) of the first portion preferably changes upwards during retorting. Then the slope changes downwards after retorting. The slope change being a free forming under surface pressure onto the foil.

[0012] Preferably the lid ring's first portion is forcibly bent downwards, to allow easier tearing-off ("peeling") of the foil as panel from the first portion of the lid ring.

[0013] Preferably the pressure applied to the sealed foil is either outer or inner pressure, acting from above or below, respectively.

[0014] The slope change is preferably taking place in all three time instances: retorting, reforming, use. The slope change during retorting and reforming is a free forming under surface pressure onto the foil.

[0015] Suggested is also a method for preparing and forming a lid (claim 10). The lid having a lid ring extending radially outside in a curl shape adapted to be seamed to a body flange of a container body, and extending radially inside in a substantially flat flange, adapted to be sealed and sealed with an edge ring of a central foil, covering an inner opening of the lid ring, radially inside of the inner end of the flat flange. In an interpretation this is a method of operating a lid (lid ring and foil), when retorting and/or cooling thereafter (claim 13).

[0016] The central foil has a tab extending from a radially outer end, preferably folded radially inside, and lying substantially parallel and close to an upper surface of the central foil.

[0017] The inner portion of the lid ring as flat flange is flexing axially upward during a retorting, and returning at least in part during cooling after retorting.

[0018] Preferably the initial position of the flange is angled downwards in the method.

[0019] The slope change being a free forming under surface pressure onto the foil.

[0020] In a further method of production or operation of a lid of claims 1 to 9, the steps as given in these claims are used (claim 12).

[0021] When a tab is provided, the problem is that the tab should be closely lying with the membrane (foil). During all the process(es) on/in the fillers production line, it should not rise up, but stay as close as possible with and along the foil, considering the length of the tab that is near the panel of the lid ring, where the foil is sealed. Still, the tab should provide a grip portion that can be gripped by an end user when wishing to open the lid, far beyond in time after the sterilization process. The grip portion can not be lying parallel and very close to the foil; it must rise up or bend away from the foil, as having this shape after sterilization and during transport and storage as well as shelf life. This appears to be a contradictory problem, even more emphasized when thin foils are more commonly used in the future, and the tab that is provided with a strip made from the same material as the foil, has no own rigidity to actively keep the position that it has been placed to.

[0022] Embodiments as explained below in Figures (sketches) support the understanding of the invention as claimed.

Sketch 1

is a view of a lid 1 having a foil 3 to close the center opening as well as an outer portion that is adapted to be seamed to a non shown body.

Sketch 2

is a similar lid with different angles of the inner portion of the lid ring.

Sketch 3a

shows an enlarged portion of the lid ring 2 with a portion of the foil, sealed to the flexible panel portion as inner portion 2b of the lid ring.

[0023] The lid ring 2 has an intermediate linking portion 2c that connects outer and inner portion 2a, 2b. In this portion 2c a score line 30 is suitably placed to allow the two portions 2a, 2b to flex or tilt against each other. This acts as circumferential hinge of the lid ring.

[0024] Figure (sketch) 1 as view shows some of the elements used in the embodiments of the invention. The inner opening 20 is closed by the covering foil 3. The lid ring 2, preferably made from metal, but could as well be stiff plastic, has an outer curl 2a that is shown in section in sketch 2 (figure 2). This curl is suitable to be seamed to a body flange not shown here, but common in the technical field.

[0025] Ring zone 9 as sealing provides a liquid tight seal of the foil 3 in its outer end ring 3b with respect to the lid ring 2 and its flange or flat ring panel 2b.

[0026] The shape of the lid ring is in this embodiment round, it can have oblong, square and elongated shape as well. An inner end 2c of the flat ring panel of the lid ring can have many shapes, an open curl, a closed curl, a flattened end of dual material layer (folded in or folded out), and a non-treated cut end. Preferred are closed curls or free cut ends that are covered by the overlying central foil. It defines the inner opening 20 closed by the foil 3 as panel.

[0027] The shape of the central foil 3 can also have many shapes in two aspects. Its basic shape depends on the shape of the lid ring 2 as explained in the previous paragraph. Its vertical shape depends on the orientation of the flat ring panel 2b, and whether this is directed horizontally, slanted upwards or slanted downwards. The central portion 3c of the panel 3 therefore is either flat, domed downwards or domed upwards. It can change its shape due to pressure exerted from the inside of the filled container during sterilization, changing the surface 3" in its shape and taking with this change of shape of a tab that is oriented parallel or along the surface 3" of the foil, to grip the tab 3d for tearing open the foil from the lid ring.

[0028] The ring surface 9 is adapted to seal the foil for providing a lid panel. The foil has an outer ring band to be sealed in a liquid-tight manner to the panel 2b.

[0029] By providing the score line 30 in the intermediate portion 2c, the hinge is allowing to move the sealed ring zone relative to the outer portion 2a. This is affected by the force F₁ which is applied to the foil 3 by inner and/or outer pressure. The pressure source can be ambient pressure (at inner vacuum) or inner pressure at a sterilizing status, acting outward.

[0030] The shape of the center foil portion 3c can vary:

• bulged outwards
• bulged inwards
• flat (horizontally).

[0031] The initial and the end position of the flange 2b of the lid ring vary in several embodiments.

(a) The portion 2b can start slanted downwards, and end slanted upwards, cf. figure 1.

(b) The portion 2c can start slanted downwards, and reach a slanted upwards angle after retorting. When pressure is reduced in the container (during and) after cooling, the final position is reached, cf. figure 2. The angle after cooling is smaller than the angle after retorting.

(c) The panel can start horizontally, and flex along the hinge 30 upwards, as "d" shows, cf. figure 3a.

[0032] In all variants, especially in variant 3, not showing the shape of the foil, a tilting movement of the portion 2b is used, relative to the portion 2a. This tilting is provided

[0033] upon pressure being applied to the foil. That center foil 3c can have flat, upward domed, downward domed shape.

[0034] The slope change done thereby is available in any of the following steps

• at retorting, and during such temperature and pressure application
• at reforming, during a cooling step after a retorting
• at a use condition at the customer, to facilitate opening of the foil from the sealing zone 9, e.g. by lowering the angle of inclination below the horizontal plane. This can be done forcibly by the end user e.g. by using a cap.

[0035] A combination of at least any two of the three varieties is preferred.

[0036] The angle is between + 30° to - 30°, or can be between 0° and 30°. Lower values of these angles are preferred, cf. claim 2.

[0037] A tab 3d can be fastened, or folded over from the outer end of the foil 3. The tab is lying parallel to the foil, close to its surface 3". This is separately displayed in Fig. 3a.

[0038] The retorting is done at up to 130 °C, preferably in a continuous retort station with no substantial counterpressure, providing sterilization to the content of the container that is closed by said lid.

[0039] In said method, the slope change is preferably an upward change during retorting, and a downward change during cooling, following the retorting in the station. These slope changes are free formings, effected by a surface pressure onto the panel 3c.

Claims

1. Lid ring for closure, said ring having a first and second attaching portion as radially inner and radially outer portions and an intermediate linking portion, connecting first and second portions,

(a) the first portion having a ring surface adapted to carry a sealed foil as panel, said foil having an outer ring band for sealing on the ring surface;

(b) said outer portion adapted to be seamed to an edge of a container body;

(c) the linking portion provided and configured as circumferential hinge, whereby

the first and second portions being tiltable relative to each other upon pressure applied to the sealed foil as panel, sealed on the ring surface of the first portion;
to change a slope (inclination) of the first portion of the ring during retorting, reforming after retort or use of the lid ring with the foil as panel sealed thereto.

2. Lid ring of claim 1, wherein the slope change is between ± 30°, preferably ± 26° or ± 20° or 0° to 20°.

3. Lid ring of claim 1, wherein the slope of the first portion changes upwards during retorting.

4. Lid ring of claim 1 or 3, wherein the slope changes downwards after retorting.

5. Lid ring of claim 4, wherein the first portion is forcibly bent downwards, to allow easier tearing-off ("peeling") of the foil as panel from the first portion of the lid ring.

6. Lid ring of claim 1, the pressure applied to the sealed foil is either outer or inner pressure, acting from above or below, respectively.

7. Lid ring of claim 1, the slope change taking place in all three time instances: retorting, reforming, use.

8. Lid ring of claim 1, where the intermediate portion is provided with a circumferential score line, for allowing the slope change of the first portion under pressure.

9. Lid ring of claim 1 or 8, the slope change being a free forming under surface pressure onto the foil.

10. Method for preparing and forming a lid (1), having

- a lid ring (2) extending radially outside in a curl shape adapted to be seamed to a body flange of a container body, and extending radially inside with a substantially flat flange, adapted to be sealed (9) and sealed with an edge ring (3b) of a central foil (3), covering an inner opening (20) of the lid ring, radially inside of the inner end of the flat flange (2b);

- the central foil having a tab (3d) extending from a radially outer end, preferably folded radially inside, and lying substantially parallel and close to an upper surface (3") of the central foil (3c);

-- the inner portion (2b) as flat flange is flexing axially upward during a retorting, and returning at least in part during cooling after retorting.

11. Method according to claim 10, wherein the initial position of the flat flange (2b) being angled downwards.

12. Method of one of claims 1 to 9, using the steps as given in any of the claims 1 to 9.

13. Method of claims 11 or 10, as using the lid during retorting and cooling after retorting and/or during using a closed container.

14. Lid ring of claim 1, having a sealed foil (3) as panel, sealed to the lid ring's first portion and providing a lid for closure.

Drawing