CAN FOR A GAS-PACKED PRODUCT

Abstract: A can comprising a can body having a top end provided with a seamed cover (4), a screw top (1) with a peripheral gasket (10) and an intermediate member (13) having at least one cut-out and disposed between the gasket and the edge of the can body. The cut-outs of the intermediate member enable venting of the space between the cover and the screw top during gas packing so that the top can be readily unscrewed prior to pulling-off or opening the cover. In addition, the intermediate member (13) includes a pre-scored blank.

Description: Can for a gas-packed product This invention relates to a container. In particular, it relates to a container such as a can for a gas-packed product. Such containers are generally intended for packaging a product which requires packaging in the presence of an inert or neutral gas or mixture of inert or neutral gases, together with a hermetic closure, in order to obtain a long shelf life. Such containers are particularly suitable for products such as powdered milk, for example. Known containers for this sort of product are typically of the type used for preserving food, which comprise a rigid metal can with a full aperture easy open end. The easy open end usually has a score around the periphery of a central panel which is broken by means of a tab so that the central panel can be removed to provide access to the product within. Since this sort of product is not intended for immediate consumption of all the product at once, various proposals have been made for closing the container between dispensing of the product. One possibilty has been to provide a flexible plastic lid. Another alternative which seeks to ensure a better seal has been to use a screw top which has an inner gasket of elastomeric material. This invention seeks to overcome unexpected problems which arise when packing a container or can under inert/neutral gases. Accordingly, there is provided a can for a product preservable in the presence of one or more inert or neutral gases, comprising a can body, a cover seamed to the body, a screw top having a peripheral gasket, and an intermediate member positioned between the gasket and the cover and including at least one cut-out for providing a vent. For packing of such cans, the can body, cover and screw top are provided to the packer together with an end for seaming to the body using traditional seaming techniques, after the can has been filled. The cover, which is preferably an easy open end, is seamed to the can body prior to supplying to the packer. This ensures the necessary seal in the conventional manner for long shelf life. The screw top is also provided to the packer and will ensure that a good seal is still maintained once the cover has, in use, been removed to provide access to the product. However, in order to allow a consumer to open the can without difficulty, the screw top must not be screwed tight onto the can body. The process of packing under inert/neutral gases, such as carbon dioxide and/or nitrogen, comprises filling the can from the opposite end to the cover and screw top, ie with the screw top underneath, placing the filled can in a vacuum enclosure, placing the end to be seamed on top of the edge of the can body, creating a relatively high vacuum in order to expel the air in contact with the product, injecting one or more inert/neutral gases, and removing the can from the vacuum enclosure in order to seam the end. If the screw top has not been screwed tight, a problem arises when the vacuum expels air confined between the screw top and the cover seamed to the can body. When the gas or mixture of gases is injected, the gas pressure tends to seat the top and its gasket more tightly on the seamed edge of the can body. The vacuum created under the top therefore can not be compensated and the top becomes very difficult to unscrew. The present invention provides a solution to this problem by the provision of the intermediate member. The cut-out or cut-outs, which may be notches, provide one or more channels between the outside of the can and the confined space under the screw top, or lid. The inert/neutral gas(es) can therefore infiltrate and compensate the vacuum created previously under the lid. The invention thus ensures that the screw top can be easily unscrewed. Once the top is unscrewed, the cover can be pulled-off. For this purpose, the cover is preferably a metal or laminate easy-open end having a score and tab as in traditional containers. In order to reclose the can and to preserve the product in a suitable way, the intermediate member is preferably removable. The gasket of the screw top then ensures that a tight seal can be obtained when the lid is screwed onto the can. In one embodiment, the intermediate member includes a pre-cut part, for example a tab and slit, and is preferably made of cardboard. The tab and slit thus can be mated so as to tranform the intermediate member into a spoon. The spoon may also correspond to a dose or measure for the product. This also has the advantage of offering manufacturers a simple and inexpensive solution to the problem of packing such spoons. Nowadays, more hygiene is required by no longer packing directly in contact with the product. A can equipped with an intermediate member in its lid which can be transformed into a spoon thus means that the filler need not be concerned with the packing of a spoon which has been already supplied. A preferred embodiment of container will now be described, by way of example only, with reference to the drawings, in which: Figure 1 is a schematic perspective view of a can with a screw lid. Figure 2 is an under plan view of the lid; Figure 3 is a partial section of the can of figure 1, placed in a vacuum enclosure; and Figure 4 is a spoon constructed from the intermediate member. Figure 1 shows a metal can intended for the packing of powdered milk. It comprises a screw top or lid 1 and a cylindrical can body 2 originally open at both ends and suitable for receiving a seamed bottom end 3 to close its lower extremity and a seamed cover 4 and the lid 1, to close its upper extremity. The can body has a necked upper part 5 and a curled top edge 6, onto which is seamed the cover 4. The seaming of the cover 4 thus forms the edge of the can body, designated hereafter by reference numeral 7 (see figure 3). On the upper necked region 5 six equidistant ribs are provided which are shaped by drawing through the inside, which together form a screw thread. The lid includes six equidistant local deformations which form a set of six ramps 9, suitable for co-operating with the six ribs 8 to provide a screw closure. The lid 1 also includes a peripheral gasket 10 made of elastomeric material (see figure 2). According to the invention, an intermediate member 13 is inserted between the edge of the can body 7 and the peripheral gasket 10. This intermediate member is usually of cardboard but may be of any other flexible material which should generally be capable of deforming to make a spoon as shown in figure 4. As shown in figure 2 , intermediate member 13 is in the form of a disc which is of a diameter sufficiently large to allow it to be snapped into the lid and held automatically under the ramps 9 , between the ramps and the gasket 10. The intermediate member 13 includes notches or cut-outs 14A, 14B and 14C, directed radially inwards, so that it covers the gasket except where the cut-outs provide vent holes for use during packing, as described below. A blank 19 is scored by perforations in the intermediate member 13 (represented by the dotted line) for construction of the spoon, shown in figure 4, by means of folding. The blank 19 comprises three parts. Part 21 corresponds to the handle of the spoon and parts 22 and 23 together form the bowl 24 of the spoon. Parts 22 and 23 are joined by a tab 25 and slit 26 co-operating to close the notch 14C. Notch 14C thus serves a dual purpose of venting during packing and providing the spoon. The use of the cut-outs as vent holes is best understood from figure 3 which shows, in section, the situation in which the can is in a vacuum enclosure under a bell jar for injection of the mixture of inert/neutral gases. The can is filled with powdered milk and the cover 4 is seamed to the can body 2. The lid 1 is screwed loosely over the covered end with the intermediate member 13 disposed between the edge 7 of the can body and the gasket 10. The other extremity of the can body simply has the end 3 placed on the can body. A high vacuum is then created under the bell jar so as to evacuate the air contained in the can and confined under the lid. Subsequently, a mixture of carbon dioxide and nitrogen is injected. The possible paths that this mixture can take are indicated here by the arrows. The inert mixture passes along arrow A under the loose end 3 to the powdered milk product. Other inert mixture is introduced along arrow B into the lid under the edge of its skirt and into peripheral space 17. The mixture is then free to penetrate along the channels created by the notches 14 into the soace 18 confined between the cover 4 and the lid 1. The vacuum previously created under the lid at 18 is thus compensated and the lid is free to be opened without difficulty. In the absence of the intermediate member, the edge 7 of the can body would become embedded in the gasket 10 under the pressure of the inert/neutral gases thus rendering the passage represented by arrow C impossible. Immediately after gas-packing, the can is routed to the seaming station for seaming the end 3. It will be appreciated that the invention has been described above by way of example only and that changes may be made without departing from the scope of the invention.

Claims: CLAIMS 1. A can for a product which is preservable in the presence of one or more inert or neutral gases, comprising a can body (2), a cover (4) seamed to the body, a screw top (1) having a peripheral gasket (10) , and an intermediate member (13) positioned between the gasket (10) and the cover (4) and including at least one cut-out (14) for providing a vent. 2. A can according to claim 1, further comprising a seamed end (3 ) . 3. A can according to claim 1 or claim 2, in which the intermediate member (13) engages the inside of the screw top (1) . 4. A can according to any one of claims 1 to 3, in which the intermediate member (13) is made of cardboard. 5. A can according to any one of claims 1 to 4, in which the cover (4) includes a peripheral score (11) and tab (12). 6. A can according to any one of claims 1 to 5, in which the intermediate member (13) is transformable into a spoon (20). 7. A can according to any one of claims 1 to 6, in which the intermediate member (13) includes a pre-scored blank (19), transformable by folding into a spoon (20).

Inventors: RICHEUX JEAN MARC, RICHEUX, JEAN, MARC
Applicants: CARNAUDMETALBOX SA, CARNAUDMETALBOX S.A.
Application year: 1993
Main classification: B65D51
IPC codes: B65D51, B65D55