GB2195971A - Pressure relief device in can end - Google Patents

Pressure relief device in can end Download PDF

Info

Publication number
GB2195971A
GB2195971A GB08622048A GB8622048A GB2195971A GB 2195971 A GB2195971 A GB 2195971A GB 08622048 A GB08622048 A GB 08622048A GB 8622048 A GB8622048 A GB 8622048A GB 2195971 A GB2195971 A GB 2195971A
Authority
GB
United Kingdom
Prior art keywords
insert plug
central panel
aperture
thermoplastics material
closing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08622048A
Other versions
GB2195971B (en
GB8622048D0 (en
Inventor
Sydney William Raxworthy
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Crown Packaging UK Ltd
Original Assignee
Metal Box PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metal Box PLC filed Critical Metal Box PLC
Priority to GB8622048A priority Critical patent/GB2195971B/en
Publication of GB8622048D0 publication Critical patent/GB8622048D0/en
Publication of GB2195971A publication Critical patent/GB2195971A/en
Application granted granted Critical
Publication of GB2195971B publication Critical patent/GB2195971B/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D81/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package
    • B65D81/3415—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package specially adapted to be heated in hot water, e.g. boil pouches
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D51/00—Closures not otherwise provided for
    • B65D51/16—Closures not otherwise provided for with means for venting air or gas
    • B65D51/1633—Closures not otherwise provided for with means for venting air or gas whereby venting occurs by automatic opening of the closure, container or other element
    • B65D51/1638—Closures not otherwise provided for with means for venting air or gas whereby venting occurs by automatic opening of the closure, container or other element by means of an element bursting upon a predetermined pressure in the container being exceeded
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2517/00—Containers specially constructed to be opened by cutting, piercing or tearing of wall portions, e.g. preserving cans or tins
    • B65D2517/0001—Details
    • B65D2517/0058—Other details of container end panel
    • B65D2517/0059—General cross-sectional shape of container end panel
    • B65D2517/0061—U-shaped
    • B65D2517/0062—U-shaped and provided with an additional U-shaped peripheral channel
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2517/00—Containers specially constructed to be opened by cutting, piercing or tearing of wall portions, e.g. preserving cans or tins
    • B65D2517/0001—Details
    • B65D2517/0058—Other details of container end panel
    • B65D2517/008—Materials of container end panel
    • B65D2517/0082—Coated or laminated metal

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Food Science & Technology (AREA)
  • Details Of Rigid Or Semi-Rigid Containers (AREA)

Abstract

A can end for closing one end of a can intended to contain a product which is subsequently to be heated before the can is opened, having a metal central panel 3, an aperture 4 in the central panel 3 and an insert plug 5 closing the aperture 4, in which said insert plug 5 is made of a moulded thermoplastics material, eg polypropylene or nylon, having a melting point greater than the maximum temperature to which the can and can end will be exposed during normal heating of its contents but less than the temperature at which the pressure within the can would be sufficient to burst open the can, such as in the range 130 DEG C-260 DEG C. The central panel may have a coating of thermoplastics material to which the insert plug is bonded. The can body may be formed by drawing with its other end integral with the body, or alternatively the can body may have a welded side seam and two can ends, each can end having an insert plug. <IMAGE>

Description

SPECIFICATION Can ends The invention relates to a can end for closing one end of a can where the contents of the can are to be heated in the can before it is opened. In particular, it relates to a can end for attachment to close one end of a can for holding food in which the food is to be heated in the closed can in boiling water before the can is opened and the food consumed.
Previously, cans for holding food to be heated, e.g. sponge puddings with a jam or syrup, have been made incorporating a soldered side seam. When the contents of the can are to be heated, the closed can is placed in a saucepan containing boiling water. Should the saucepan boil dry and become overheated, and the can 'come into direct contact with it, the pressure caused by the overheated and expanding contents would force open the soldered side seam and so relieve the internal pressure. Any liquid present in the food might then leak out of the can but would be retained in the saucepan.
It is now intended to use cans, such as welded side seam cans or drawn one-piece cans, which are inherently stronger than the soldered side seam cans. However, should the contents of such an inherently strong can be overheated, a higher pressure would be wallowed to build up in the can and the can would then be liable to burst open, causing a violent explosion.
It is an object of the invention to provide a safety device, by which the internal pressure produced in the can by overheating may be released in a controlled manner before it reaches the pressure required to burst open the can, in order to prevent such an explosion.
According to the invention there is provided a can end for closing one end of a can intended to contain a product which is subsequently to be heated before the can is opened, having a central panel, an aperture in the central panel and an insert plug closing the aperture, in which said insert plug is made of a moulded thermoplastics material having a melting point greater than the maximum temperature to which the can and can end will be exposed during normal heating of its contents but less than the temperature at which the pressure within the can would be sufficient to burst open the can.
Preferably the insert plug is made of a moulded thermoplastics material having a melting point in the range 130"C-260"C.
Preferably the central panel has a coating of thermoplastics material to which the insert plug is bonded.
The invention also resides in a can closed at one end by a can end as defined above.
Various embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which: Figure 1 is a plan view of a can end having an aperture closed by an insert plug; Figure 2 is a cross-section of the can end on the line ll-ll in Fig. 1; Figure 3-5 are detailed views of alternative embodiments of the invention.
In Fig. 1, a can end 1 has a peripheral cover hook formation 2 and a metal central panel 3.
An aperture 4 in the central panel 3 is shown by dashed lines and is closed by an insert plug 5 made of moulded thermoplastics material.
As shown in Fig. 2 the insert plug 5 extends through the aperture 4 and also extends laterally around the aperture. The isnert plug 5 is fused onto a coating 6 of thermoplastics material to improve the adhesion. It can be manufactured by clamping the can end 1 between upper and lower dies (not shown) which define the shape of a mould so that, upon injecting the molten plastics material, the plug 5 is moulded in situ and the heat of the plastics material causes fusion of the plug 5 to the coating 6. Alternatively, the plug 5 can be manufactured by inserting a rivet of suitable material into the aperture 4 and heat-forming and adhering it to the can end 1.
The can end 1 is for attachment to close a can containing food. The material of which the insert plug 5 and the coating 6 are made are able to withstand the processing and reheating conditioning to which the can and contents will be exposed, such as temperatures of 120 C to 130 C for sterilisation and 100"C for reheating before consumption. The melting point of the material of the insert plug must therefore be at least 130 C, but sufficiently low that, should the can and contents be overheated, the insert plug will melt before the pressure within the can is sufficient to burst open the can.
The following are suitable materials for forming the insert plug 5 and coating 6: Insert Plug Melting Point Suitable Coating food grade polypropylene 160 C-180 C preformed polypropylene film laminated to metal nylon 240 C-260 C epoxy layer or nylon laminate The insert plug 5 may be formed in different shapes so as to close the aperture 4. Some alternative embodiments having recessed surfaces of different forms are shown in Figs. 3-5. In addition, the insert plug may be marked with a trade mark, if required. The size of the insert plug in relation to the aperture must be such that it will not creep under pressure during thermal processing or reheating.
Can ends incorporating insert plugs in accordance with the invention may be attached to different types of cans. For drawn one-piece cans, only one can end is required. For other types of cans, such as welded side seam cans, having a tubular body, two can ends incorporating insert plugs may be used. This has the advantage that whichever way the can is placed in a saucepan for heating, the insert plug in the can end in direct contact with the heat will melt first, and that any liquid escaping from the can will pan into the bottom of the saucepan and is unlikely to spurt out from it.

Claims (7)

1. A can end for closing one end of a can intended to contain a product which is subsequently to be heated before the can is opened, having a central panel, an aperture in the central panel and an insert plug closing the aperture, in which said insert plug is made of a moulded thermoplastics material having a melting point greater than the maximum temperature to which the can and can end will be exposed during normal heating of its contents but less than the temperature at which the pressure within the can would be sufficient to burst open the can.
2. A can end as claimed in claim 1 in which said insert plug is made of a moulded thermoplastics material having a melting point in the range 1300C-2600C.
3. A can end as claimed in claim 1 or 2 in which the central panel has a coating of thermoplastics material to which the insert plug is bonded.
4. A can end substantially as hereinbefore described with reference to the accompanying drawings.
5. A can closed at one end by a can end as claimed in any of the preceding claims.
6. A can as claimed in claim 5 in which the can body is formed by drawing, with its other end integral with the body.
7. A can having a tubular body with a welded side seam, the body being closed at each end by a can end as claimed in any of claims 1 to 4.
GB8622048A 1986-09-12 1986-09-12 Can ends Expired - Lifetime GB2195971B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8622048A GB2195971B (en) 1986-09-12 1986-09-12 Can ends

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB8622048A GB2195971B (en) 1986-09-12 1986-09-12 Can ends

Publications (3)

Publication Number Publication Date
GB8622048D0 GB8622048D0 (en) 1986-10-22
GB2195971A true GB2195971A (en) 1988-04-20
GB2195971B GB2195971B (en) 1990-04-18

Family

ID=10604115

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8622048A Expired - Lifetime GB2195971B (en) 1986-09-12 1986-09-12 Can ends

Country Status (1)

Country Link
GB (1) GB2195971B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2304825A1 (en) * 2005-10-28 2008-10-16 Bsh Electrodomesticos España, S.A. Gas hob

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB659191A (en) * 1949-02-18 1951-10-17 Metal Box Co Ltd Improvements in or relating to metal containers
GB1310540A (en) * 1969-07-22 1973-03-21 Bosch Gmbh Robert Pressurized fluid reservoirs fitted with safety devices
GB2126979A (en) * 1982-09-17 1984-04-04 Sodastream Ltd Bottles
US4452275A (en) * 1982-11-17 1984-06-05 Nobuyuki Sugimura Safety device for an accumulator
US4580690A (en) * 1985-04-11 1986-04-08 Sexton Can Company, Inc. Coinless pressure relief device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB659191A (en) * 1949-02-18 1951-10-17 Metal Box Co Ltd Improvements in or relating to metal containers
GB1310540A (en) * 1969-07-22 1973-03-21 Bosch Gmbh Robert Pressurized fluid reservoirs fitted with safety devices
GB2126979A (en) * 1982-09-17 1984-04-04 Sodastream Ltd Bottles
US4452275A (en) * 1982-11-17 1984-06-05 Nobuyuki Sugimura Safety device for an accumulator
US4580690A (en) * 1985-04-11 1986-04-08 Sexton Can Company, Inc. Coinless pressure relief device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ES2304825A1 (en) * 2005-10-28 2008-10-16 Bsh Electrodomesticos España, S.A. Gas hob

Also Published As

Publication number Publication date
GB2195971B (en) 1990-04-18
GB8622048D0 (en) 1986-10-22

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19920912