GB2233635A - Container - Google Patents

Abstract

A container for sealing with a closure (38) has an opening surrounded externally by a finish (10), comprising a sealing surface tapered downwardly and inwardly and having at least two projections (18) thereon. The closure (38) has a top panel (40), a depending peripheral skirt (42) for sealing engagement with the sealing surface and a sealing compound (44) on at least the internal surface of said skirt to form a seal against at least a part of the sealing surface with the projections at least partially embedded therewithin to provide yieldable resistance to rotational movement of the closure about the axis of the container. <IMAGE>

Description

CONmINER This invention relates generally to containers, and is particularly, although not exclusively, concerned with glass containers for use in the storage and/or cooking of food. It will be convenient to hereinafter describe the invention with particular reference to glass food containers, but it is to be understood that there are other applications of the invention.

With previously proposed glass containers it has been difficult to produce a closure which allows for ease of removal, while providing a seal having good abuse resistance, and being strong enough to undergo full retorting. Such a closure must provide a vacuum seal which is able to survive extremely arduous cooking processes under retort for the food products contained therein, without failure or destruction. The seal must also be able to survive packaging, transport, and handling of the container prior to the closure being removed by a consumer, but it must also be such that a consumer may remove the closure without great difficulty.

We have previously provided a glass container made with a Hartford finish, having a sear-off bead against which gasket compound of a closure seals. The seal generated by this arrangement withstands retorting, and provides excellent abuse resistance. However, the closure is extremely difficult to remove, and consumer frequently found it necessary to use a tool, often a kitchen utensil such as a knife to assist in breaking the vacuum created by the seal. Such a practice is potentially dangerous, and a need is evident for closures that can be more readily removed by hand.

Another problem with many existing containers is their lack of aesthetic appeal to a consumer, after removal of the closure. Consumers have been reluctant to use such containers at the table due to their inelegan~e.

For instance, a container with a threaded neck will not generally be used for serving food.

With the advent of microwave ovens, and their ever-increasing use in many homes, there is a need for a container which contains pre-processed foods which may be reheated in a microwave oven prior to use, and then may be placed directly onto a table for serving. Such a container alleviates the need for transfer of the food, either prior to or after reheating, to a separate container for serving.

ft is an object of the present invention to provide a container adapted to seal with a closure to provide a seal with satisfactory abuse resistance, which allows the closure to be removed by a consumer easily, and yet is not unsightly, and may be resealed with the original closure.

The present invention provides a container adapted to seal with a closure, said container comprising a container body having an opening surrounded externally by a finish, said finish comprising a sealing surf ace tapered downwardly and inwardly, and having at least two projections thereon, said closure comprising a top panel, a depending peripheral skirt for sealing engagement with said sealing surface, and a sealing compound on at least the internal surface of said skirt to form a seal against -at least a part of said sealing surface with said projections at least partially embedded therewithin to provide yieldable resistance to rotational movement of the closure about the axis of the container.

The container has an opening surrounded by a finish. A finish is a term used in the art to describe that part of the container about the opening which is adapted to seal with a closure The finish of the container is preferably adapted to seal with a closure having a top panel and a depending peripheral skirt. A sealing compound may be located on at least the internal surface of the skirt, so that when the finish is in sealing relationship with the closure, the sealing compound forms a seal against the sealing surface.

The finish of a container according to the present invention includes a sealing surface which is tapered downwardly and inwardly. The taper is preferably at a slight angle to the direction of the longitudinal axis of the cntainer. In a preferred form said angle is in the range of about 1 degree to lO\degrees.

The sealing surface of the container is tapered in order to not only provide a sealing relationship with the sealing compound of the closure, but to act as a retention means to resist removal of the closure va movement in the axial direction of the container. While the tapered sealing surface provides such retention, it does not prevent rotational movement of the closure to any degree beyond that which -is provided by adhesion between the sealing compound and the sealing surface.

In a preferred form, the sealing surface extends from the top corner at the uppermost portion of. the container to a shoulder at the bottom of the finish. The shoulder preferably forms a restriction about the container having the general appearance of a neck The body of the container is formed below that neck.

The thickness of the finish in this preferred form decreases from the top corner of the sealing surface to the shoulder, due to the downward and inward taper of the sealing surface.

At least two projections are provided on the sealing surface of the finish. Said at least two projections may be formed integrally with the sealing surface, and are preferably arranged circumferentially and syzmetrically spaced thereabout. Any number of projections may be provided. For example 4 has been found satisfactory in practice, Preferably, the projections are partially embedded within the sealing compound of the closure when the closure is in sealing relationship with the. finish of the container. As opposed to the taper of the sealing surface of the finish, the projections provided on the sealing surface may provide resistance to the rotational movement of the closure.In this respect, the configuration of the projections is preferably such that rotational movement is resisted to a certain extent, but on the application of a greater force, rotational movement is allowed. In this way, accidental rotation of the closure, which may be caused for example by a heavy knock whilst the container is being handled or transportea, is avoided, but deliberate rotation1 as would be caused by a consumer rotating the closure, is allowed.

The degree of rotation which is allowed by the projections is preferably only such that the action of the projections on the sealing compound in the region thereof is sufficient to apply a force to the closure capable of distorting either the peripheral skirt or the top panel.

This distortion results in the deformation of the closure to a degree where the vacuum seal is broken. Once the vacuum seal is broken, the closure may be easily removed, such as by hand.

In a preferred form of the invention, the projections are pillars which may, for example, be semi-circular in radial cross-section. Preferably the pillars extend in the axial direction of the container from a first point at or below the start of the tapered section to a second point at or near the shoulder at the bottom of the sealing surface. In a preferred form of the invention the pillars project beyond the sealing surf ace only as far as the vertical plane containing the top corner of the sealing surface, in which case the pillars will have a triangular cross-section in the axial direction. Alternatively, the pillars may project beyond that vertical plane to provide projections with a part-conical cross-section in the axial direction of the container. Further, the pillars may be all the same or slightly different.

It is to be understood tha the radial cross-section of the projections is preferably such that'a slight degree of rotational movement is permitted to distort the closure sufficient to allow its removal, while not allowing movement such that the closure may be accidentally rotated. In this respect, it should be noted that the projections may have a partially ellipsoid, or similar, radial cross-section, which allows for the movement descr d.

It is also generally preferred that the sealing compound of the closure, when the closure is in a sealing relationship with the finish of the container, extends to a point above the bottom edge of the projections. Thus the projections are not completely embedded within the sealing compound. They are only partially embedded so that the seal is created with the top edge and sides of the projections only, as well as with the sealing surface itself, and the top corner of the finish.

A preferred form of closure has a pop-panel as the top panel. The pop-panel is preferably suitable to indicate when the vacuum seal of the closure has been broken. Thus, when the seal is intact, the pop-panel is elastically deformed inwardly. On release of the vacuum the 'panel reverts to its at rest position, emitting a noise similar to a "pop". Such a panel also provides tamper evidence.

The depending peripheral skirt of the closure preferably has a rolled-in bead thereabout. The raw end of such a rolled-in bead may be covered by sealing compound to protect that raw end from rust or the like.

In a preferred form the sealing compound extends down the internal surface of the skirt far enough to also cover the raw-end of the rolled-in bead.

A container according to the present invention may be suitable for use with food products which require processing prior to their sale and ulvim.zte use. in a preferred form, and prior to such processing, a food product is placed within the container, and a suitable closure may be heatea with steam in order to both sterilise the closure and soften the sealing compound prior to the application of the closure to the container.

In this way, as the closure is applied to the container, a small amount of steam is trapped within the empty space above the food product, and the sealing compotssnS is softened to a degree whereby the top edge of the tapered sealing surface may be easily embedded therein. The sealing compound may then be placed in sealing relationship with the rernainder of the sealing surface, as well as about each of the projections.

After the closure has thus been aplied to the container, the container and closure are preferably contacted with cold water, in order to induce condensation of the steam trapped within the empty space above the food product, which condensation provides a partial vacuum within the container to strengthen the seal between the container and the closure.

The sealed container may then be subjected to retorting, the conditions of which are dependent upon the type of food product being processed, but which generally include an increase in temperature to a point well beyond the boiling point of water, the maintenance of a temperature in order to cook the food product, and then subsequent lowering of the temperature at a predetermined rate. The use of such high temperatures generates further vapour from the food product, and causes a substantial rise in the internal vapour pressure within the empty space above the food product. Accordingly, the seal already created between the container and the closure, and the overpressure or mechanical pressure available in the retort, must bz such that the vapour pressure subsequently generatea does not break the seal and blow the closure off the container.

After retorting, and as the container and the food product are allowed to cool, further condensation within the container occurs, leading to the formation of E substantial vacuum within the container. The purity of the seal may then be checked for vacuum release, and may also be mechanicalry tested for its strength. The container with the fully pre-processed food product is then ready for transport to the point of sale, having a vacuum seal with very good abuse resistance making it unlikely that the seal will be broken due, for exarwle, to rough handling.A consumer may then purchase the container without risk of the food product being "off" due to the vacuum being broken at an earlier stage, and may reheat the contents in an oven such as a microwave oven, after removing the closure.

The action of removing the closure is readily achieved by twisting the closure by hand, causing the projections of the .sealing surf ace of the container to distort the closure to a sufficient degree to break the vacuum. The closure may then be easily removed in the axial direction of the container by forcing the depending skirt of the closure over the tapered sealing surface of the finish of the container. In this respect, it should be noted that the slight angle of the tapering of the sealing surface, combined with the flexibility of the sealing compound and skirt of the closure, allow for the easy removal of the closure Once the closure has been removed, the container may be used by the consumer for serving the food product.In this respect, the finish of the container is not unsightly, and is not of the type that has an appearance which would make a person reluctant to use the container in this way.

Alternative methods of removing the closure are also available. One such method is the insertion of a coin between the closure bead and the container shoulder, which is then twisted on its horizontal axis to lever the closure upward, and thus vent atmosperic pressure into the partial vacuum inside the container.

It will be convenient to hereinafter describe two particular embodiments of the invention, examples of which are shown in the accompanying drawings. However, those drawings are not to be understood as showing the only possible forms of a container according to the invention.

In the drawings: Figure 1 is a partial cross-sectional view of a container finish according to a first eznbodiment of the present invention; Figure 2 is a partial cross-sectional view' of a container finish according to a second embodiment of the present invention; Figures 3a and 3b are side views of a container having the finish cf either Figure 1 or 2; Figure 4 is a partial cross-sectional view of a preferred Myme of closure for use with a container according to the present invention; and Figure 5 is a partial cross-sectional view of the closure of Figure 4 as applied to the finish of Figure 1.

Illustrated in Figure 1 is a container finish 10 having a tapered sealing surface 12 beginning at top corner 14 and tapering inwardly and downwardly to a shoulder 16. Sealing surface 12 has thereon a projection in the form of a pillar 18. Pillar 18 has a generally triangular cross-section, extends from a first point 20 near the top corner 14 to a second point 22 adjacent shoulder 16, and does not project beyond the vertical plane (up and down the page with respect to the drawings) which contains top corner 14.

Figure 2 illustrates a second embodiment of a container according to the present invention. In this embodiment, a pillar 24 projects from a tapered sealing surface 26, to a point beyond the vertical plane which contains top corner 28. Pillar 24 thus has a semi-conical cross-section in the axial direction.

The embodiment of Figure 1 is generally preferred, and it is also preferred that the angle of taper of the sealing surface (for either sealing surface 12 or 26) be in the range of about 1 to 100 from the vertical. In this case, for a container with a diameter of about 75rrLT, and a sealing surface having a width of about 3 n;n, the pillars will project beyond the sealing surface by an amount of about 0.3 mm.

Figure 3a shows a container 30 in a preferred shape, having a finish 32 which includes tapered sealing surface 3M. Pillars 36 are shown in side view on sealing surface 34, having a semi-circular cross-section in the radial direction as is further illustrated by the exploded Lop-view of Figure 3b.

In Figure 4 a preferred form of closure is illustrated which is suitable for use with a cootair,er according to the present invention. Closure 38 has a top panel 40, a depending peripheral skirt 42, and z rolled-out bead 46 Sealing compound 44 is applied to the inside of skirt 42. Preferably, top panel 40 is a pop-panel, suitable to indicate when the vacuum seal of the closure has been broken.It should also be noted that bead 46 may alternatively be a rolled-in bead, and that the raw end of such a rolled-in bead may be covered by sealing compound to protect that raw end from rust or the like Closure 42 is of metal, but may be of any suitable closure material, and sealing compound A4 may similarly be of any suitable material.

Preferably, the compound material is such that it provides an adequate. thickness of compound in the area of the closure which seals with the container, and has a lubricant system designed to optimise the removal characteristics of the closure. The compound preferably also withstands the retorting, adheres to the internal coating system of the closure, and compresses and is shaped so a reseal is obtainable.

The seal created by a closure such as that illustrated in Figure 4, and a container finish such as that illustrated in Figure 1 is shown in Figure 5. Figure 5 illustrates a pillar 18 partially embedded in the sealing compound 44.of a closure 38. The top corner 14 of the finish 10 is also embedded in the sealing compound 44 to provide a satisfactory vacuum seal. Sealing compound 44 does not seal about the pillar 18 below its bottom edge 46, but does seal with the top edge and sides of the projection, as well as with the sealing surface 48. In the regions about the periphery of the container finish where there are no projections, the sealing compound will seal only with the sealing surface and the top corner of the finish.

A container according to the invention may be of glass, and is preferably constructed by independent section processes, requiring contact of glass with metal components by pressing very viscous glass into an upside down blank cavity, and forcing air into the cavity to mould the glass using guide-plates, ring moulds and body moulds.

Thus, a container may be provided which, in conjunction with an appropriate closure allows for easy removal of the closure, and is resealable, while also having a seal with improved abuse resistance, Those skilled in the art will appreciate that there may be many variations and modifications of the configurations described herein, which are within the scope of the present invention.

Claims (11)

CLAIMS:

1. A container adapted to seal with a closure, said container comprising a container bod having an opening surrounded externally by a finish, said finish comprising a sealing surface tapered downwardly and inwardly, and having at least two projections thereon, said closure comprising a top panel, a depending peripheral skirt for sealing engagement with said sealing surface, and a sealing compound on at least the internal surface of said skirt to form a seal against at least a part of said sealing surface with said projections at least partially embedded therewithin to provide yieldable resistance to rotational movement of the closure about the axis of the container.

2. A container according to claim 1, wherein the projections are pillars which extend in the axial direction from a position adjacent or near the top of the sealing surface to a position adjacent or near the bottom of the sealing surface.

3. A container according to claim 2, wherein said pillars are semi-circular in radial cross-section.

4. A container according to claim 2 wherein said pillars are ellipsoidal in radial cross-section.

5. A container according to any one of claims 1 to a wherein said projections project beyond the sealing surf ace to a position about an imaginary vertical plane containing the top of the sealing surface.

6. A container according to any one of claims 1 to 5 wherein said projections project beyond the sealing surf ace to a position beyond an imaginary vertical plane containing the top of the sealing surface.

7. A container according to any one of claims 1 to 5 wherein when the container and the closure are in sealing relationship, said sealing compound does not envelope the projections below the axially lowermost part thereof.

8* A container according to any one of claims 1 to 7 wherein the top panel of the closure is a pop-panel.

9. A container according to any one of claims 1 to 8 wherein the skirt of the closure includes a rolled-in bead the end of said rolled-in bead.

10. A container according to any one of claims I to 9 wherein the angle of taper of the sealing surface is from 19 to 10 from vertical.

11. A container according to claim 1 substantially as herein described with reference to the accompanying drawings.