Vacuum packing apparatus for perishable foods

Abstract: A plastic container (8) has a lid (14) sealed with O-ring (16) and has a hole (20) in lid (14) over which is fitted a cup-shaped valve (28) held loosely in position by bolt (22) which passes through hole (20) and is secured by spaced-apart locknut (24). A vacuum source (33) is connected by hose (46) to rubber cup (38) which can be placed over cup-shaped valve (28) to evacuate air from container (8), after which cup (38) is removed by squeezing with hand, causing cup-valve (28) to seal against flat surface of lid (14) by atmospheric pressure. Container (8) is then placed under refrigeration for long term preservation of its contents.

Description: Background - Field of Invention The present invention relates to an apparatus for vacuum packing perishable foods. In particular, to such an apparatus for use by restaurants, food service industries, and home. Background - Field of Prior Art Vacuum packing is a recognised technique for storing and preserving perishable foods. Seafood is very commonly vacuum packed in plastic bags by fish wholesalers, but this method is not practical for restaurants, food service industries, or homes, because the necessary equipment is very expensive and cumbersome. Even in cases when restaurants can afford such machinery, it is commonly considered too time-consuming and costly for them to pack all their perishable foods in such manner. Instead, most restaurants use plastic storage containers as a means of keeping their perishable foods. Such plastic storage containers, however, have air inside them after the lid is placed on. As a result, food such as shrimp, squid, crab, and the like, to mention only a few, when stored in such containers, will often spoil within 24 hours, even under refrigeration. For such items, vacuum sealing is most desirable. However, although there have been two other methods of vacuum sealing in the prior art, neither is comparably simple or as convenient as the present invention. For example, Zaccard, in U.S. Patent 2,654,521 provides an apparatus for evacuating and capping jars. However, the Zaccard device must use jars especially designed to accept covers, which are in turn held in a specially adapted rack, which is manipulated from outside the vacuum chamber. The complexity and clumsiness of this design makes it unsuitable for daily or frequent use, and is in fact useful only when substantial quantities of food are to be put in relatively long-term storage. Rossi, in U.S. Patent 3,943,987 (1971) showed individual containers which are fitted with check valves, which can be connected to a vacuum source. A problem with the Rossi approach is the need for a leak-free valve, which must be fitted to each individual container. Therefore, neither Zaccard nor Rossi is quick or convenient enough for regular restaurant or home use. Moreover, the best level of vacuum achieved by either method is only 40%. Further, vacuum containers are known wherein the pressure compensation opening is closable by an elastic sealing plate. A problem with these constructions is that the plate lifts up and is often displaced with each suction stroke, which is undesirable for such sealing plate valves. The problem is alleviated in Swiss Patent CH-A-274829, where the plate is held in place during vacuuming, and a flap valve is provided in the sealing plate, positioned above the pressure compensation opening. Figs. 3 and 4 - Prior Art Heretofore, vacuum containers have been used with various types of check valves, some flat and some of the plug or solid variety. A flat check valve 48 (Fig. 3) tends to curl up at edge 50 when under constant vacuum, and it is therefore unreliable. A plug or solid valve 52 (Fig. 4) requires an extremely smooth surface hole in which to seat. Otherwise, it leaks under high vacuum. Objects and Advantages One object of the present invention is to provide an apparatus for vacuum sealing containers which is both easy and convenient, making it suitable for use in the food service industry, restaurants and home. Another object of the invention is to provide an apparatus of vacuum sealing containers of various sizes and shapes, which can also be used for frequent resealing after the initial opening. Another object is to provide an 85% vacuum. A further object is to provide a fail-safe valve that will not leak under high volume. Brief Description of Drawings Fig. 1 is a perspective view of a food container for vacuum packing, according to the invention; Fig. 2 is a sectioned view of the top portion of Fig. 1; Fig. 3 is a sectioned view of a flat valve of prior art; Fig. 4 is a sectioned view of a solid plug valve of prior art; Fig. 5 is an exploded sectioned view of a cup-valve according to the invention; Fig. 6 is a perspective view of a vacuum cup; and Fig. 7 is a perspective view of the vacuuming apparatus of the present invention. Description - Figs. 1 and 2 The present invention provides a method of vacuum sealing a lightweight plastic container 8, Fig. 1, which has an opening 10 defined by a rim 12 and which uses a lid 14 for covering the container opening. Container 8 includes an O-ring seal 16 (Fig. 2) corresponding in size and shape to rim 12 and edge 18 of lid 14. Lid 14 has a centrally mounted rubber check or cup-valve 28 loosely located in position over hole 20 by a bolt 22, which passes through hole 20 and is retained by locknut 24 which is spaced apart from lower face 26 of lid 14. Loose fitting bolt 22 and spaced apart locknut 24 allow cup-valve 28 limited freedom to move sideways and vertically to at least the position shown by phantom lines 30. A hand positioned rubber cup 38 (Fig. 1) is attached to vacuum tube 46 and is of sufficient internal diameter to be placed freely over rubber cup-valve 28, or removed therefrom as desired. Fig. 2 shows a sectional view of cup 38 in position over cup-valve 28 and in contact with top surface of lid 14. When vacuum pump 33 (Fig. 7) is energized, vacuum line 46 (Fig. 2) will be partially exhausted. Since line 46 is connected to rubber cup 38, cup 38 will be exhausted also. The vacuum in cup 38 will be maintained by a contact seal between cup opening 29 and top of lid 14. This vacuum will lift cup-valve 28 off its seat 32, whereby cup-valve 28 will rise up slightly to the position shown by phantom lines 30. This raised position of cup-valve 28 permits air from inside container 8 to flow out through hole 20 in lid 14, under valve 28, into space 39 inside cup 38, and thence to outlet pipe 44 and vacuum hose 46. This evacuation of air from inside container 8 causes a reduction of air pressure in container 8 and this, combined with atmospheric air pressure above lid 14, forces lid 14 down against O-ring seal 16, forming an airtight seal with top surface 12 of container 8. After sufficient vacuum, preferably .25 in mercury or lower, as shown by gauge 36 (Fig. 7), has been obtained inside container 8 by vacuum pump 33, cup 38 can be removed from its position over cup-valve 28 by squeezing cup 38 sideways with the thumb and forefinger. This will allow air to enter space 39 (Fig. 2) inside cup 38, thereby breaking the vacuum. Cup-valve 28 will immediately seal against top surface of lid 14, due to the difference in air pressure exerted against outer surface of cup-valve and the vacuum inside container 8. When one desires to remove food 6 (Fig. 1) from container 8, cup-valve 28 can be squeezed sideways between thumb and forefinger, permitting air to enter container 8, thus allowing lid 14 to be easily removed. Resealing can be effected immediately by first replacing lid 14 over container 8, then cup 38 over cup-valve 28, as shown in Fig. 1 and 7, and then switching on vacuum pump 33. As soon as the desired vacuum is reached, cup 38 is removed and sealed and container 8 is returned to the refrigerator. The speed at which this process can be achieved is a surprising result of the present invention. It is not necessary to physically hold cup 38 in position over cup-valve 28 during the vacuuming process. All that is required is to place the cup in position, and it will immediately be held in place by suction until physically removed. After use, cup 38 can then be used to exhaust another cup-valved container. Thus, it will be seen that many food containers can be exhausted in the space of a very few minutes. Fig. 5 Cup-valve 28 has proved, under extensive test, to overcome the problems associated with both the flat and solid plug valves of Figs. 3 and 4. It seals consistently under the identical conditions which cause the others to fail. Preferably, cup-valve 28 is made of resilient material, has a hollow interior 56 about 12 mm (1/2 in) in diameter, and is generally dome-shaped inside for rigidity. Cup-valve 28 preferably has an outside diameter of about 18 mm (3/4 in). Stepped portion 60 provides a second but smaller hollow 62, which has a ridge 74. Fig. 6 Cup 38 (Fig. 6) preferably is made of resilient material and has a hollow interior 78 about 25 mm (1 in) in diameter. This hollow interior is about 18 to 25 mm (3/4 to 1 in) deep, so as to provide room for cup-valve 28 to lift freely from its seat during exhaustion. Ramifications and Scope The container of the present invention will maintain a vacuum of 85%, thus increasing the food storage life well above what is possible with the 40% vacuum now prevalent in the vacuum packaging industry. The cup-valve of the present invention can be adapted to use in conjunction with a hole which can be drilled in lids of such plastic food pan lids as are currently in use by most restaurants, thus transforming such pans into vacuum food containers. The container itself may be formed of glass, metal, plastic or any other suitable material. However, the preferred material is a lightweight plastic such as polycarbonate. Preferably, the rim of the lid has a groove to occupy the rubber O-ring. Alternative devices within the scope of the present invention could easily be conceived by those skilled in the art. For example, a salad bar, as found in some restaurants, could have food containers placed in wells and a vacuum system attached to the lids, which could be brought down over the food containers at the close of each day, thus allowing simultaneous vacuuming of all containers, and thus preserving the salad materials for another day.

Claims: Apparatus for vacuum sealing containers, the containers having an opening therein, and the apparatus comprising a check valve for co-operating with said opening and air extraction means (38) adapted to fit over the check valve, said extraction means (38) being hollow and couplable to a vacuum source (33) whereby air can be extracted therefrom, charactrised in that the check valve comprises: a cup (28) which has a rim (76) which is larger than said opening (20) such that when said cup (28) is placed over said opening (20) with said rim (76) against said container (18), said rim (76) will encompass and hermetically seal said opening (20), and a retention means (22,, 24, 64, 72), associated with said cup (28), for permitting said rim (76) of said cup (28) to be lifted away from said opening (20) to unseal said opening (20), and for preventing said cup (28) from being removed from the proximity of said opening (20). The apparatus for sealing containers under vacuum of Claim 1, characterised in that said retention means comprises an elongated member (22) which extends through said opening (20) and has one end (64, 72) which is engaged in said cup (28) and has an opposite end with stop means (24) which is larger than said opening for retaining said elongated member in said opening. Apparatus according to Claim 1 or 2, characterised in that the cup (28) is resiliently deflectable in order to break the vacuum between the interior of the container (18) and atmosphere. Apparatus according to Claim 1, 2 or 3, characterised in that the cup (28) is held loosely captive by said retention means comprising said elongate member (22) having a head (64) loosely engaged in the cup, and held captive to the container part by means of a nut (24) representing said stop means. Apparatus according to Claim 4, characterised in that the cup (28) comprises a base and a side wall, and interiorly of the side wall is a ledge (74) by which the cup is held captive to the head of the bolt (22). Apparatus according to Claim 5, characterised in that the outer wall has a stepped configuration so that at the opposite end from the base, the cup (28) is of larger diameter. Apparatus according to any preceding claim, characterised in that the apparatus includes a two part container of which the parts are adapted to be sealingly connected so as to define a container in which a vacuum can be maintained. Apparatus according to Claim 7, characterised in that one of said parts is a container body having a base and a side wall, and the other part is a lid (14) carrying a seal member (16) which engages the top edge (12) of the body wall when the parts are in assembled condition, and said check valve is carried by the lid (14). Apparatus according to Claim 7 or 8, characterised in that the said container parts are in clear plastics material such as polycarbonate.

Inventors: SCANLAN GREGORY, SCANLAN, GREGORY
Applicants: EVERFRESH MFG CORP, EVERFRESH MFG CORPORATION
Application year: 1989
Main classification: B65B31
IPC codes: B65B31