GB2061891A - Method and apparatus for vacuum sealing containers - Google Patents

Abstract

A container to be vacuum sealed is provided with one or more small air passages through which air may be withdrawn from the container, a flexible sealing material being provided adjacent each such passage to permit air to be withdrawn from the container when it is placed in an evacuated chamber but which seals these passages when the air pressure in the evacuated chamber is rapidly returned to the ambient air pressure. In the embodiment of Fig. 1 a tubular plug 63 collapses to block passageway 61 when air is admitted to vacuum chamber 23 via valve 33. In the bag embodiment of Fig. 10C, a valve 117, stuck to the bag, contains an air-filled balloon 137 which expands to open aperture 111 by moving lever 125 against the action of spring 129. Fig. 10D (not shown). Expansion of the balloon occurs when air pressure surrounding bag and valve is reduced and the air in the bag is thereby removed. When ambient conditions are restored the balloon collapses and aperture 111 is resealed; subsequently the bag is heat sealed between its contents and the valve and the latter is removed. <IMAGE>

Description

SPECIFICATION Method and apparatus for vacuum sealing containers This invention relates generally to the art of vacuum sealing containers, particularly for the purpose of preserving a substance therein such as food.

Vacuum sealing of containers is widely employed. The air pressure within the container after filling with the substance to be preserved is reduced by at least forty percent below the ambient air pressure and the container is then sealed against any further air transfer between the inside of the container and the outside.

when it is desired to use the substance inside, the seal is then broken, which restores the ambient air pressure within the container, and the substance is then removed and used.

Existing techniques utilized to vacuum seal food products generally involve cooking the food product in the container and then sealing the container while hot, wherein the pressure within the container is reduced below ambient pressure upon cooling. A lid with a flexible gasket seal is generally held on the top of a jar or other container as a result of the difference in air pressure between the outside and inside of the container. Other suggested techniques for vacuum packing substances such as foods, without the necessity for cooking or heating in the container, include the connection of a vacuum hose through a check valve to each of the containers in turn, or a complicated manipulation of a container lid within a vacuum chamber to position it on the container while a vacuum is being maintained in the chamber.

It is the principal object of the present invention to provide a simple and convenient technique and apparatus for initially vacuum packing material in containers, resealing vacuum packed containers after opening and the opening of vacuum sealed containers, especially adapted for in home use.

This and additional objects are accomplished by the various aspects of the present invention wherein, briefly and generally, a container with a substance to be preserved therein is placed within a vacuum chamber, a lid is positioned thereon but retaining small air passages into the container through which air is withdrawn in the vacuum chamber. A flexible sealing element is positioned adjacent such small passages in a manner that does not interfere with air being withdrawn from the container but which does seal the passages when the air pressure in the vacuum chamber is allowed to rapidly return to the ambient air pressure. A rapid increase in air pressure in a space surrounding the container causes an air pressure differential between the inside and outside of the container since the passages thereinto are too small to rapidly transfer air back into the container.This pressure differential instantly causes the sealing material to close off the small passage or passages into the container, thus preserving the vacuum within the container. One technique for subsequently unsealing and opening the container is to again place it in the vacuum chamber and reduce the air pressure in a space surrounding the container until it is substantially equal to the reduced air pressure within the container. At this point, the seal is broken since it is the air pressure differential between the inside and outside of the container that has maintained the seal intact. The air pressure within the chamber is then allowed to slowly return to the ambient air pressure in a manner that air returns through the passages into the container without causing the seal to be actuated.Both of these techniques for sealing and unsealing containers are accomplished at a uniform temperature, preferably room temperature, in significantly less than 1 minute without any need to attach anything to the container or mechanically manipulate the lid or any other part of the container. These techniques and apparatus for carrying them out are particularly adapted for use in the home to seal, reseal or unseal food containers.

In the accompanying drawings: Figure 1 illustrates in cross-sectional form a vacuum sealing apparatus with a container theren being sealed in accordance with the technique of the present invention; Figures 2A and 2B show an enlarged view of a part of the container of Fig. 1; Figure 3 is a view of a pad upon which the container of Fig. 1 rests; Figure 4 illustrates a different container lid construction than that illustrated in Fig. 1; Figure 5 illustrates another lid construction that is different from those of Figs. 1 and 4; Figure 6 illustrates the sealing technique of the present invention utilized with an existing lid and container construction; and Figures 7A and 7B illustrate a particular technique for vacuum unsealing a vacuum sealed container.

Referring initially to Fig. 1, the construction of a vacuum sealing apparatus suitable for carrying out the techniques of the present invention will be described. The apparatus of Fig. 1 is designed especially as a home appliance. A base 11 of the appliance includes an upper plateform 1 3 through which a small hole or passage 1 5 is provided near an outside edge of the platform 13, the platform 1 3 being circular when viewed from the top. A vacuum hose 1 7 provides an air passage between the hole 1 5 and an electrically driven vacuum pump 1 9 that is positioned within the base 11.Appropriate controls 21 are provided on the outside of the base 11 and may include, for instance, an electrical on/off switch, a light to indicate when the vacuum pump 1 9 has drawn the air pressure down as far as it will go, or a timer that may be set to operate the vacuum pump for a predetermined time.

A cover 23, made of a very strong unbreakable material and preferably transparent, is cooperatively shaped in size for sitting on the base 11 to form a vacuum chamber 25 therein. A material very suitable for this container is polycarbonate plastic that satisfy these criteria. The container 23 is generally cylindrical in shape with its bottom being open and a round knob 27 at its top which permits it to be lifterd on and off of the base 11 by hand. The cover 23 is sealed to the base 11 by a sealing gasket 29 that is held within a groove 31 provided in a short vertical cylindrical surface as part of the platform 1 3 but having a diameter less than the inner diameter of the bottom opening of the cover 23.The sealing ring 29 is of any suitable soft, rubber-like material that will prevent air from passing into the chamber 25 when a vacuum is being drawn therein.The ring 29 is preferably stretchable so that it may be removed from the annular groove 31 for cleaning but the groove 31 normally holds the ring 29 in place on the base 11.

The vacuum pump 1 9 and associated parts should be capabie, at a minimum, of reducing the air pressure within the enclosed chamber 25 at least forty percent below the ambient air pressure around the appliance. This is the minimum "vacuum" required for food canning. Of course, the lower the air pressure the better and something in excess of a seventy percent reduction in air pressure within the chamber 25 is possible with existing small vacuum pumps of the type that can be utilized for the pump 1 9. To enable long term storage of all types of foods, where it is necessary to inhibit bacteria growth, an air pressure reduction in excess of 95% below the embient air pressure is desired.

In order to return the air pressure within the chamber 25 from the reduced level to the ambient air pressure, a hand-operated valve 33 including a resilient rubber button 35 is attached to an end of a rod 37 that is positioned within a vertical aperture 39 that extends through the handle 27. A spring 41 is provided within the handle 27 and urges the sealing button 35 up against the underside of the top of the cover 23 to close off the passage 39. The spring 41 pushes between the knob 27 and a pushbutton 43 provided at an opposite end of the rod 37. When the pushbutton 43 is depressed, the button 35 moves into the chamber 25 in a manner illustrated in dotted outline in Fig. 1. Air thenis allowed to enter the chamber 25 through holes 45 through the walls of the passage 39.

These holes, the size of the air passage 39 and the distance of travel of the button 35 are made sufficient so that air can pass into the chamber 25 therethrough fast enough to return the air pressure therein to the ambient air pressure in less than 2 seconds from the lowest air pressure that is possible to obtain with a particular vacuum pump 1 9. As explained hereinafter, this rapid build up of pressure within the chamber 25 is a mechanism by which a container seal is effected.

An air passage to restore air pressure within the chamber 25 could alternatively be positioned in the base 11 but the valve placement and structure of Fig. 1 have certain advantages. By making the valve 33 independent of the air passage 1 5 which feeds to the vacuum pump 1 9, the air passage 1 5 may be made smaller since it is thus not used to move large amounts of air quickly back into the chamber 25. The slower drawing of a vacuum in the chamber 25 by operating of the pump 1 9 does not cause such a large air flow since it may take 20, 30 or even 40 seconds to reduce the pressure within the chamber 25 to a desired level.The small passage 1 5 means that there is thus less chance of food or other materials spilled from containers within the chamber 25 of falling into the passage 1 5 and clogging it. Also, by having the valve at the top of the chamber 25 the air rushing into the chamber urges a lid of the container to its desired sealing position where, on the other hand, air rushing up from the bottom of the chamber 25 tends to want to blow a container lid held only by gravity off of the container.

A base 47 of a container, comprising the base 47 and a lid 51, is loaded with food or other material 49 and then covered with the lid 51. At least ten and preferably twenty percent or more of the volume within the container 47 is unfilled in order to leave enough room for a sufficient lid sealing vacuum to be drawn. Solid food material may be placed near the top of the container 47 since, depending upon the particular food, there is likely to be significant air between the solid particles. Liquid or semi-liquid food, however, cannot be filled up to the top of the container 47 but must leave enough air space to provide a satisfactory vacuum seal by the sealing technique to be described hereinafter.

The container 47 rests on the platform 1 3 that is provided with a circular shape rubber mat 53 (Fig. 3) that contains a plurality of slots 55 extending radially from the outside towards the inside of the mat 53. The grooves 55 provide an air path underneath the container 47 which can be important when, in the case of the container shown in Fig. 1, there is an air passage provided by an upward curving bottom surface of the container 47. If the air passage slots 55 are not provided, a drawing of a vacuum in a chamber 25 can adhere the container to the mat 53 or other surface provided on the platform 1 3 when the air pressure within the chamber 25 is returned to ambient pressure.This may occur if air is not permitted to re-enter the space under the container 47 when the air pressure is returned in the chamber 25 to ambient pressure. The slots 55, however, allow such an air pressure return and permits free removal of the container 47 from the chamber 25 when the sealing operation is concluded.

The container lid 51 of Fig. 1 is particularly designed, to make vacuum sealing possible without any mechanical valve manipulation, connection of vacuum hoses or the movement of the lid 51 in order to effect a seal. The lid 51 includes as a principal element a solid piece 57, preferably made of polycarbonate plastic. The piece 57 is circular in plan view and contains a downwardly depending circular portion having a diameter that is less than the diameter of the opening of the container 47 for which the lid 51 is designed to mate.

Within the depending cylindrical portion is provided an annular groove 59 which serves to hold a sealing ring 60. Sealing ring 60 is made of flexible rubber-like material and is preferably slightly sticky on its outside surfaces. The ring 60 can be removed from the lid 51 for cleaning if it is stretchable to be removed from the annular groove 59.

An aperture 61 is provided from the bottom side of the lid through the main portion 57 and out of a side wall in which a plug 63 is frictionally held. The plug 63 has a narrow passage 65 through its entire length and its outer most segment includes a length of thin walled tubing 67 made of a flexible rubberlike sealing material that itself is also preferably somewhat sticky on at least its inside surface along the passage 65.

The plug 63 serves as a one-way valve which operates in a unique manner. When the air pressure within the chamber 25 is being reduced below ambient pressure, air will be drawn from the inside 49 of the container 47 through the passages 61 and 65 and into the chamber 25 area, for evacuaton through the vacuum pump 1 9. Some air will also be withdrawn around the seal 60 and the top of the container 47 since the lid 51 is merely sitting on top of the container 47 without any force applied between them or any mechanical connection. These air flows are indicated by solid arrows in Fig. 1.Once the pressure within the chamber 25 has been reduced to a desired level, usually as much as the vacuum pump 1 9 is able, then the operator of the appliance rapidly pushes the knob 43 of the valve 33 downward in order to open up the passages for air to return into the vacuum chamber 25. These air flows are shown by the dotted arrows in Fig. 1 within the chamber 25. If the air pressure in the chamber 25 is returned to ambient air pressure fast enough, preferably in less than 2 seconds, the tube 67 of the plug 63 will collapse and seal the container before any substantial amounts of air are allowed into the container through the passage 61. Fig. 2A shows the plug 63 in its starting shape and Fig. 2B shows the plug with its tube 67 collapsed in accordance with the container sealing procedure just outlined.

Slight amounts of air will tend to pass back into the container 49 through the small passages left at the junction of the seal 60 and the top of the container 47 but this operates in a similar manner; that is, the passages are not large enough to carry air to the interior of the container 49 fast enough to equalize the pressure so that an instantaneous pressure differential results between the inside of the container 49 and the remaining space within the vacuum chamber 25. This pressure differential causes the lid 51 to be pushed tightly against the container 47 and the seal 60 closes off any air passages that might have existed. To open the container again, the plug 63 is removed by hand. Air then rushes in through the passage 61 to equalize the pressure within and without the container 47. The lid 51 is then easily removed.

Other specific forms of a one-way valve used according to the present invention are shown in Figs. 4, 5 and 6. In each case, the sealing technique is the same; that is the evacuation of the chamber 25 to reduce the air pressure by at least forty percent and then the air pressure is allowed to suddenly return to the ambient pressure fast enough to exclusively cause the seal to close off passages into the container, a time period that is usually less than 2 seconds.Small air passage(s) through or around the flexible rubber-like seal(s) described permit air to be slowly withdrawn from inside the container as the air pressure in a space surrounding the container is reduced but are not sufficient to allow enough air to pass back into the container as the surrounding air pressure is rapidly increased, thereby to create a pressure differential tht compresses the seal and closes off the passage(s). The lid in each case is not mechanically attached to the bottom container but rather is held thereon only by its own weight before sealing and by the differential air pressure inside and outside the container after sealing.The embodiments of Figs. 1 and 4 could have their lids previously sealed, if desired for some reason, because an additional one-way valve exists which could operate alone in the manner described to seal the container; but it is simpler to use the lids as shown and described herein. In each of the Figs. 4, 5 and 6, corresponding but different elements of the containers among themselves or to those of the Fig. 1 container are given the same reference characters but with a prime (') added.

Referring to Fig. 4, the lid solid piece 57' has a vertical hole 69 therein. During the vacuum sealing operation, a piece of flexible rubber-like sealing material 71 that is somewhat sticky on at least its bottom side is laid on the top of the lid. The stickiness on the bottom side of the seal 71 prevents it from moving around on the lid due to any vibration that is created in the appliance as the motor driven vacuum pump is operated. The seal 71 is much larger is diameter than the diameter of the hole 69 and is made thick enough so that it is not drawn down into the hole 69 when the container is sealed. As a vacuum is drawn in the chamber 25 during the sealing operation, air escapes from the container through the hole 69 and around the top of the container 47 at the seal 59'.When the air pressure is suddenly allowed to return to the ambient air pressure, this seal 71 is pushed firmly down against the top of the lid in accordance with the air pressure differential mechanism that has been described before.

When the container is to be opened, the sealing material 71 is stripped off the top of the lid to allow air to enter the container through the passage 69. That then releases a physical seal at the seal 59' and the lid is then easily lifted off. The embodiment of Fig.

1 has an advantage that the containers may be stacked one on top of another while the embodiment of Fig. 4 suffers from the disadvantage of interferring with such stacking although a recess in the top surface of the lid 57' around the hole 69 may be provided to loosely accommodate the seal 71 so that the top surface thereof is flush with the top surface of the seal 71 to obviate the aforementioned disadvantage. Also, the open passage 65 in the plug 63 allows air to be drawn out of the container faster in the embodiment of Fig. 1 than in the embodiment of Fig. 4 wherein the air passages for this purpose are much smaller.

Referring to Fig. 5, the lid 51 is the same as that described with respect to Fig. 1 except that a solid plug 63' has been substituted for the plug 63 of Fig. 1. This lid structure can result in more time being taken to evacuate the interior of the container since the only air passages for that purpose are around the top of the container 47. When the container is to be opened, the plug 63' is removed by hand and air enters through the passage 61 to release the lid 51.

Referring to Fig. 6, a standard canning lid is shown sitting on a container 73. The lid includes a thin metal circular piece 75 having a soft rubber-like plastic sealing ring 7.7 attached to its underside. As in the Fig. 5 case, air escapes around the top of the container 73 under the seal 77 when the space around the container is evacuated. When the air pressure suddenly increases from an evacuated state, the seal 77 is pushed tightly against the top of the container 73 as in other embodiment described previously.

Several specific embodiments have thus been described of a container and a sealing technique that is convenient and economical as an alternative to home canning techniques presently being used. Containers can even be opened and reclosed according to these techniques a number of times. This extends the storage life of foods and other perishable products. The lids and containers can be reused a number of times.

Referring to Figs. ,7A and 7B, the use of the vacuum sealing apparatus of Fig. 1 is illustrated for unsealing a jar 79 with a screw-type lid 81 having a sealing ring on the inside thereof. This container will be recognized as a popular type of food sold in grocery stores.

The lids are often hard to remove because the containers have been vacuumed sealed. But that vacuum seal is broken if the space surrounding the container 79 is evacuated to a pressure in the vicinity of or lower than the pressure within the container 79. Once such evacuation has taken place, the air pressure in the space surrounding the container is permitted to slowly increase by just slightly depressing the knob 43 to allow air to re-enter the vacuum chamber 25 and raise its pressure back to ambient pressure. It has been found that this rise in pressure should be accomplished in no less than 7 seconds in order to prevent the container from resealing. Once back to ambient pressure, the container 79 is removed and the lid 81 is unscrewed from it.

Of course, the same technique of evacuation and then slowly allowing the air pressure to return to the ambient pressure can be used for unsealing any of the other containers illustrated and discussed hereinabove.

Referring to Fig. 8, an air return valve structure is illustrated that is different than the valve structure 33 shown in the previous figures. The same reference characters are used in Fig. 8 to identify corresponding parts previously illustrated but with a prime (') added thereto to distinguish them. The principal change is in a lower valve seat 35' of the valve structure 331. The spring loaded valve seat is shown in Fig. 8 as being depressed by hand force in order to provide openings through which air rushes into the evacuated chamber 25'. The shape of the valve seat 35' is conical with a matching surface 40 so that a normal rest position causes the two conical surfaces to exactly mate and prevent air from normally entering the chamber 25'. An angle - of the conical surfaces 35' and 40 that is made with a vertical line is preferably less than 40', in one embodiment about 30o, in order to direct the incoming rush of air down against a top of a container that is positioned within the chamber 25'. An advantage to the shape of Fig. 8 is that this rush of air is directed in a manner to quickly press the lid against the top of the container and form a seal therearound before the air pressure within the container is allowed to increase significantly.

Referring to Fig. 9, another lid structure is illustrated in cross section for use on the container 47. A circular piece of plastic 85, shown in cross section in Fig. 9, forms the main portion of the lid structure. In an annular groove provided in its bottom surface is permanently glued a silicon rubber sealing ring 87 for contacting and sealing again the top wall edge of the container 47. During evacuation of the chamber in which the container 47 is placed, air is withdrawn from the container around the seal 87 as the lid loosely fits on top of the container. As previously described, the seal 87 is compressed as the air pressure is rapidly increased in the region above the lid, thereby to preserve the contents of the container 47.

On the top surface of the lid plastic piece 85 is a boss 89 that is circular in cross section and provided with threads on its outside cylindrical surface. A cap 91 contains mating threads on its inside cylindrical surface to permit loosening and tightening of the cap 91 by an appropriate rotation.

A vertical aperture 93 is provided all the way through the top lid portion 85 and the boss 89 in a manner that would permit air to move therethrough if the cap 91 is not in place. The cap seals off the passage 91 from the surroundings, however, through its contact with a pointed annular ring 95 extending upward on top of the boss 89. In order to relieve the pressure within the container when it is desired to remove the lid, one or more vertical slots 97 are provided in the outside surface of the boss 89 into its grooves. With one or more slots 97, a slight loosening of the cap 91 will break the seal from the underside of the cap and the pointed annular ring 95, thereby allowing air to enter under the cap 91, through the slot 97 and down into the container through the passage 93.The cap and boss structure of Fig. 9 has an advantage as a controllable sealing mechanism of providing a very good seal for a long period of time until it is desired to open the container. The pointed annular sealing ring 95 is most conveniently formed as a unitary structure with the cap 91 by injection molding the entire piece at once.

Fig. 10, in its six views, illustrates a sequential method of vacuum sealing food or other material within flexible plastic bags using an appliance of the type previously illustrated with respect to Fig. 1. A flexible plastic bag 101 is illustrated in Fig. 10A. The bag 101 is made of a heavy material that can withstand the forces created by large pressure differential between the inside and the outside of the bag. Three sides of the bag are closed but a fourth side 103 remains open. One face of the bag is conveniently marked with lines 105, 107 and 109 positioned as shown in Fig. 1 or, the purpose of these markings being explained later. A hole 111 is provided in that same surface of the bag 101 and is used in the vacuum sealing process. Alternatively to providing the hole 111, a marking may be applied and the user of the bag may make the hole at the mark.

The remaining illustrations of Fig. 10 show how the bag 101 is used to vacuum seal material. Food or other material 11 3 is placed in the bag through its open end 103 and the opened end is then sealed by applicaton of heat and pressure along the line 105 to form a weld 115, as shown in Fig. 1 orb.

The next step is to attach a one-way air valve structure 11 7 to the bag 101, as shown in Fig. 10C. Valve 11 7 includes a bottom structural plate 11 9 having a rigid box-like structure 121 attached. An opening 1 23 is provided for a valve beam 1 25 having a valve member 1 27 attached at one end and a spring 1 29 in compression between its other end and the bottom plate 11 9. An adhesive layer 131 is carried by an underside of the bottom plate 119. The adhesive layer 131 can be a double adhesive tape or other material adapted for many uses or designed for a single adhering use to be replaced when the valve 11 7 is used again.A hole 1 33 is provided through both the plate 11 9 and adhesive layer 131 and is aligned with the hole 111 of the bag 101 when the valve 117 is used. The valve member 1 27 is positioned to close off the opening 1 33 in its rest position as urged by the spring 1 29.

The case 121 includes a plurality of apertures 1 35 to make sure that the air pressure within and without the cse 1 21 is substantially equal as the valve 11 7 is used to seal the bag 101. Within this compartment is an air-filled balloon member 1 37. Its relative size as shown in Fig. 10C is with the valve 11 7 outside the vacuum chamber and thus under normal atmospheric pressure.Enough air is placed in the balloon 1 37 for it to function by expansion during the sealing operaton, as explained hereinafter, but not so much air that it would interfere with the normal closed valve 1 27 as biased by the spring 1 29. The balloon element 1 37 need not be attached to any of the other structure of the valve 11 7, but could be if preferred, so long as the case 1 21 holds it in position over the beam 1 25 for use in sealing.

After the valve 11 7 is adhered to a surface of the bag 101 as shown in Fig. 10C, the entire structure is placed within the vacuum chamber 25 of the appliance illustrated in Fig.

1. The air pressure within the chamber 25 is reduced, as described previously. As this happens, the balloon 1 37 with its captured volume of air expands to fill up the inside of the case 121 of the valve 117, as shown in Fig.

10D. The force of the air pressure within the balloon 1 37 pushes down on the beam 1 25 and overcomes the force of the spring 129, thereby to open the valve 1 27 to allow air to be withdrawn from within the bag 101. Since the bag 101 is flexible, withdrawal of most of the air causes the bag to shrink around the material 11 3 within it.

After the air has been so removed by drawing the maximum vacuum within the chamber 25, the button 43 at the top of the applicance of Fig. 1 is pushed in a manner described previously to allow the air pressure within the chamber 25 to return rapidly to an ambient pressure. As the pressure within the chamber 25 increases, the size of the balloon element 137 decreases, as shown in Fig. 10E. The result is that the spring 1 29 causes the valve 127 to close again to seal the bag 101.

When the pressure within the chamber 25 has returned to the initial atmospheric pressure, the balloon 1 37 returns to the size initially illustrated in Fig. 10C.

Once the pressure within the chamber 25 is so returned to that of its surroundings, the bag 101 and the valve 11 7 attached thereto are removed from the chamber 25. Another heat sealing operaton is then performed along the line 109 (Fig. 1 OA) and is marked for that purpose on a surface of the bag. Once sealed in this manner, the valve 11 7 can be removed by breaking the adhesive attachment to the bag 101. The excess bag material may then optionally be removed by cutting along the line 107, resulting in a vacuum sealed bag 101 which preserves the material 11 3 therein. Removal of the material 11 3 is accomplished by tearing into the bag 101 and the bag is thereafter discarded.

Referring to Figs. 11 A and 11 B, a modification of the applicance of Fig. 1 is illustrated wherein the base structure 11 is modified to include the plastic bag sealing, cutting and punching tools that are used in the process just described with respect to Fig. 10. These tools are conveniently provided for use adjacent the vacuum sealing appliance but yet in a manner that they can be pushed into the base portion 11, out of the way, when not in use.

Referring to Figs. 11 A and 11 B, a door 141 is hinged at its bottom and shaped to form a continuous smooth surface in the base portion 11 when closed. When the door 141 is opened, a button 143 provided on the underside of the base 11 causes, when pushed by a user, a spring-loaded rack structure 145 to move out from the base 11 into the position shown in Figs. 11 A and 11 B for use. Attached to the rack 145 are two wheels 147 and 149 in a manner that they can freely rotate when motion is applied. The wheels are held in a journal relationship to the rack 145 in a manner to leave a small gap 1 51 therebetween through which the bag 101 of Fig.

10 may be drawn across its width along one of the lines 105 and 109 to effect a desired heat sealing of the plastic bag material. The heat is applied by an electrical element within the wheel 149 (not shown) to which electrical power is provided by a pair of brushes 1 53 and 155.

Attached to the top of the rack 145 is a plastic hole punch 1 57 that is carried by a leaf spring 1 59. If the bags 101 of Fig. 1 OA are provided the user without the hole 111 but rather with a mark showing where the hole is to be placed, the punch 1 57 may be manually operated by the user to form the hole 111 as an initial step in use of a bag.

Similarly, a knife 1 61 is provided on the top of the rack 145, having two stationary sharp edges 163 and 165. Then bag 101 may be cut across its marked line 107 by the knife 1 61 in practicing the method of Fig. 10.

The knife 1 61 is rotatably carried by the rack 145 through a journalled connection 167.

This permits the user to position the knife in the most convenient position for use.

When a sealing operation is completed, the rack 145 is manually pused back into the base structure 11 against a spring that tends to urge the rack 145 to its extended position shown in Fig. 11. A latch (not shown) holds it in place until the button 143 is again pushed by the user to release the latch. The door 141 is also closed to restore the base to the original condition.

Claims (34)

1. A method of sealing a container having an opening, comprising the steps of: positioning a flexible sealing element adjacent the opening in a manner to seal the container when a predetermined force is applied thereto but providing an air passage through said opening when such force is not applied, said positioning occurring while the container is in an ambient air pressure environment, drawing air out of the container through said air passage by reducing the air pressure in a space surrounding the container, and sealing said element over the opening of the container without physical contact therewith by suddently returning the air pressure in said space to said ambient pressure, whereby a difference in air pressure provides said predetermined force to hold the sealing element in a manner to seal the container opening.

2. The method according to Claim 1 wherein said container comprises an open mouthed base and a lid; the positioning step comprising laying said lid over the open mouth of said base with a soft resilient material between the lid and the container base, whereby the step of drawing air causes air to pass through spaces between the lid and the container base constituting said opening and the sealing step causes the lid to compress the soft resilient material against the mouth of the container base.

3. The method according to Claim 1 wherein said container comprises an open mouthed base and a lid; the positioning step comprising laying a self-supporting piece of soft rubber-like material as the sealing element over said opening which is located in said lid, said opening having significantly smaller dimensions than those of said material piece.

4. The method according to Claim 1 wherein said container comprises an open mouthed base and a lid to close said open mouth, the lid being larger than the open mouth of the base and having an opening which communicates through said lid to said base when the former is placed on the latter, the positioning step comprising positioning in said opening said sealing element in the form of a small diameter thin walled tube made of a soft rubber-like material which collapses under the influence of said predetermined force, to seal the container.

5. The method according to Claim 1, comprising the steps of: providing in conjuncton with said passage a one-way air valve which allows air to escape from within the container through the passage when air pressure outside the container is less than that inside the container and which seals said passage when the air pressure outside the container is suddenly increased from that on the inside of the container without any physical contact or mechanical energy necessary to be applied directly to the valve.

6. The method according to Claim 5 wherein the container comprises an open mouthed base and a lid to close said open mouth; the method further comprising laying said lid over said open mouth in a manner that the lid rests on the mouth through a soft rubber-like material, whereby the step of drawing air out of the container causes air to pass through the spaces between the lid and the open mouth of the base and the step of suddenly returning the air pressure causes the lid to compress the soft rubber-like material against the mouth of the base.

7. The method according to Claim 6 wherein the step of drawing air out of the container includes the step of placing said container within a vacuum chamber and drawing a vacuum in said vacuum chamber.

8. The method according to Claim 7 wherein the step of suddenly returning the air pressure within said vacuum chamber includes the step of directing air from without the chamber downward from the top of the chamber against the container lid, whereby a quick seal is obtained as the air pressure within the chamber begins to rise.

9. The method according to any one of Claims 1 to 8 wherein the step of drawing a vacuum comprises reducing the air pressure in said space by at least forty percent of the ambient air pressure.

1 0. The method accoding to any one of Claims 1 to 9 wherein the step of suddenly returning the air pressure substantially to the ambient air pressure is accomplished in less than two seconds.

11. The method according to Claim 5 wherein said container is a flexible plastic bag being enclosed around material to be vacuum sealed therein except for small air passage in the form of an aperture through one wall thereof, said one-way air valve being temporarily adhered to said bag over said aperture, said bag with said valve attached being placed in a vacuum chamber wherein the steps of drawing air out of the bag and suddenly returning the air pressure to the ambient air pressure takes place.

1 2. The method according to Claim 11 which comprises the additional steps of, after the air pressure within the chamber has been returned to the ambient air pressure, removing the bag with valve attached from the chamber, sealing the bag adjacent said aperture and removing the valve from the bag, whereby the material within the bag is vacuum packed for storage.

1 3. A method of storing material in a container having a removable lid carried by a top of said container with a flexible seal held therebetween, comprising the steps of: placing the material to be stored within the base of the container, positioning said lid on the container top with said seal therebetween without applying mechanical force thereto, reducing the pressure of air in a space around said container, whereby the air pressure is also reduced within said container by air being withdrawn between the loose fitting lid and container, and suddenly returning the air pressure in said space to said ambient air pressure, whereby the lid and container top are pushed together in a manner compressing the sealing material to close off any air passages therebetween.

14. A method of breaking a seal between a lid and a top of container wherein the air pressure within the container is significantly less than outside ambient air pressure, comprising the steps of: reducing the air pressure in a space surrounding said closed container to a level substantially the same as that within said container, whereby said seal is broken by equalizing the pressure within and without said container, and slowly returning the air pressure in said space to the ambient air pressure in a manner that the lid does not reseal with the container, whereby the lid may be removed from the container with ease by hand.

1 5. A vacuum sealing apparatus, comprising: a base structure, a removable cover dimensioned to fit on said base and provide an enclosed chamber therein, a seal carried by said base in a position to be contacted by said cover when positioned on said base, a vacuum pump carried in said base and connected through an aperture in the base to said chamber in a manner to reduce the air pressure within said chamber when the pump is operated, an aperture in the top of said cover that allows air to move into said chamber from outside said cover, and a manually operable valve carried in said aperture, said valve being normally biased closed to seal said aperture but being manually operable to let air pass into said chamber to equalize any air pressure differences within and without of said chamber.

1 6. The vacuum sealing apparatus according to Claim 1 5 wherein said vacuum pump is capable of reducing the air pressure within said chamber by at least forty percent.

1 7. The vacuum sealing apparatus accoding to Claim 1 5 or 1 6 wherein said aperture is of such a size and said valve of such a construction as to permit sufficient air to enter through the aperture into the chamber to restore in less than two seconds the ambient air pressure therein from an initial air pressure created by the vacuum pump that is less than forty percent of said ambient air pressure.

1 8. The vacuum sealing apparatus according to anyone of Claims 15 to 17 wherein said cover contains a handle extending above its top surface on the outside thereof with said aperture extending through said handle and the top wall of said cover.

1 9. The vacuum sealing apparatus according to any one of Claims 1 5 to 18 wherein said seal is shaped in the form of a ring and said base has an upstanding annular groove in which said seal is installed, thereby to prevent the seal from vertical motion while at the same time allowing it to be removed by hand for cleaning.

20. The vacuum sealing apparatus according to any one of Claims 1 5 to 1 9 wherein said base is provided with a surface within said vacuum chamber for the purpose of supporting a container being vacuum sealed that comprises grooves extending toward the center of said supporting surface from an outside thereof, thereby to prevent a vacuum seal from occurring between a container and said surface.

21. The vacuum sealing apparatus according to Claim 20 wherein said container supporting surface comprises a removable rubber pad that is loosely laid on said base and which is cut away in a plurality of grooves extending from an outside edge toward its center.

22. The vacuum sealing apparatus accoding to any one of Claims 1 5 to 21, which additionally comprises: a container for food or other material to be stored, said container being rigid and open at its top to form a circular lip, and a lid carrying a soft rubber-like sealing material in the shape of a ring positioned within an annular groove of the lid, said sealing ring and groove being shaped to receive the top lip of said container.

23. The vacuum sealing apparatus accoding to Claim 22 wherein said lid additionally comprises: an upwardly extending boss from a top surface of said lid, an aperture extending completely through said lid and said boss, a pointed annular ring carried by the top of said boss and extending around a top end of said aperture, and a cap adapted for threaded attachment to the outside of said boss to push an underside surface thereof against said annular ring when desired to seal said passage.

24. The vacuum sealing apparatus according to any one of Claims 1 5 to 21 which additionally comprises a flexible plastic bag in which food or other material may be vacuum sealed and a one-way valve adapted for removable attachment to said bag, said valve being characterized by opening an aligned aperture into said bag when placed in said vacuum chamber and the air pressure therein reduced below a given level, said valve further characterized by closing said mating aperture when the air pressure within the chamber returns to said given level.

25. The vacuum sealing apparatus accoding to Claim 24 wherein said valve comprises: a valve seat surrounding an aperture adapted to be aligned with an aperture in said plastic bag, a layer of adhesive carried by said valve to hold it in place with said apertures aligned, a valve stem carried by said valve structure and operable against said valve seat to close off said aperture and to be removed therefrom to open said aperture, a resilient element carried by said valve in a manner to hold said valve stem normally against said valve seat to close off said aperture, and means carried by said valve for overcoming said resilient means when the surrounding air pressure falls bellow a given level, whereby said valve is caused to open under such a low pressure situation.

26. The vacuum sealing apparatus according to Claim 25 wherein said means for overcoming the force of the resilient element comprises a balloon-like element containing some air and held in an enclosed volume so that its expansion causes the countervailing force to be applied.

27. The vacuum sealing apparatus according to any one of Claims 1 5 to 26 wherein said base additionally comprises: a rack carried in a manner to be slid into and out of said base by an operator, and means carried by said rack for applying heat and temperature to plastic bags to seal them.

28. The vacuum sealing apparatus according to any one of Claims 1 5 to 27 wherein said manually operable valve and said aperture in the top of said cover are cooperatively conically shaped in a manner to form a seal when the manually operable valve is in its closed position.

29. For a container having a top opening formed by an upward termination of container walls, a lid comprising a solid structure adapted to extend across said opening and rest upon the upper terminaton of said container wall, said lid comprising: an annular groove positioned and dimensioned for receiving the top of the container walls, a sealing material attached to the innermost surface of said groove, thereby to provide a seal with the top edge of said container walls when the lid is being used, an upwardly extending boss from a top surface of said lid, an aperture extending completely through said lid and said boss, a pointed annular ring carried by the top of said boss and extending around a top end of said aperture, and a cap adapted for threaded attachment to the outside of said boss to push an underside surface thereof against said annular ring when desired to seal said passage.

30. A lid adapted for vacuum sealing to a container, said lid having an air passage therein extending from a bottom surface through said lid and out of a side wall thereof, an air sealing plug being provided for removable insertion into said passage as it emerges from the lid side wall, whereby the vacuum seal may be easily broken by removal of the plug that is positioned not to interfere with vertical stacking of said containers.

31. The container lid according to Claim 30 wherein said plug is solid.

32. The container lid according to Claim 30 wherein said plug includes a thin walled hollow tube extending outward thereof and forming an air passage through the plug, said tube being formed of a flexible sticky rubberlike material that is characterized by being closeable in response to a sufficient air pressure differential occurring between the inside of said plug passage and the outside.

33. A vacuum sealing container comprising a flexible plastic bag of rectilinear shape in one view with the two long sides and the short side closed, leaving one open short side through which food or other material to be vacuum sealed may be placed, a small aperture being placed in one wall of the bag adjacent its said open end but a given distance therefrom, said bag including three substantially parallel markings across the width of said bag in the vicinity of its said open end, one of said markings being positioned between the open end and the aperture and the other two markings being positioned a distance from the aperture on a side removed from the open end of said bag.

34. A pressure sensitive valve mechanism adapted for vacuum sealing material in containers, comprising: a surface adapted for contacting said container, an adhesive layer on said surface adapted for adhering the valve to said container surface, an aperture through said adhesive and valve surface adapted to be superimposed over an aperture in said container, a valve member operable between a position that closes off said aperture and another position that opens said aperture for air to pass therethrough, means including a resilient element for normally biasing said valve into its closed position, and a balloon-like element containing a quantity of gaseous material and which is physically constrained to overcome the force of said biasing means when the air pressure surrounding the valve falls below a given level that is a fraction of atmospheric pressure, whereby said valve automatically operates to open a container for withdrawing air therefrom when the surrounding air pressure falls below said given value.