Vacuum generating device for sealing perishable products and method of use
A vacuum sealing device comprises a lid having a rigid rim with a lower opening for receiving a dish, an impermeable elastic membrane peripherally affixed to the rigid rim for sealing the dish, and a valve-less air evacuator formed between the elastic membrane and the dish rim. The valve-less evacuator allows air to flow out of the dish when the lid is being pressed and becomes closed when the lid is released to cause said lid to rebound to form a vacuum in the dish. The rigid rim prevents lid deformation when the lid is pressed, thus enabling the vacuum formation. To facilitate lid removal, the device has a valve-less vacuum releaser comprising a finger-receiving chamber and a section of the elastic membrane located above the chamber and connected to the rigid rim for releasing the vacuum in the dish. To prevent vacuum loss during storage in freezer or fridge, the elastic membrane is sufficiently thinned prior to being affixed to the rigid rim. In use, one places the lid on a dish, forces air out of the dish via the air evacuator between a section of the elastic membrane and the dish rim by pressing the lid, and releases the lid to cause the air evacuator to close and vacuum to form in the dish. To restore the device's capability to generate and maintain vacuum after numerous uses, the lid is exposed to a hot fluid having a temperature higher than 45° C. for a period of time.
This is a divisional patent application of the application Ser. No. 11/499,280, filed Aug. 5, 2006, which is to be issued as U.S. Pat. No. 7,594,586.
FIELD OF THE INVENTIONThis invention relates to a vacuum generating device for perishable products such as food, and is an improvement for the applicant's U.S. patent application Ser. No. 10/917,016.
BACKGROUND OF THE INVENTIONIn commercial and home vacuum packaging, food is often placed in a plastic vacuum bag and the bag is subsequently evacuated and sealed by a vacuum seal appliance such as FoodSaver® or Seal-a-Meal® sealer. For average homes, such method is too labor intensive and complex for daily food storage. Moreover, the vacuum bag is normally disposed after one use, which is expensive and not environment friendly.
It is also known to place food in a vacuum container and evacuate the container either by connecting the vacuum seal appliance to the container lid via a vacuum tube as taught by FoodSaver® or Seal-a-Meal® sealer or by manually removing air via a check valve in the lid as taught by Wang in U.S. Pat. No. 6,557,462. Such vacuum containers are susceptible to air leakage and plugging of the check valve and vacuum release valve in the lid by food. The check valve and vacuum release valve in the lid are also difficult to clean, which is not desirable for food storage.
In the applicant's earlier invention disclosed in U.S. patent application Ser. No. 10/917,016, it was taught to seal food in existing kitchen containers with a vacuum lid comprising a rigid ring and an elastic membrane attached to the rigid ring.
The present invention is to provide a new vacuum storage device to simplify the process of sealing food and other spoilable products and to solve the problems with the vacuum storage devices described above.
SUMMARY OF THE INVENTIONThe invention provides a vacuum sealing device having a lid for a dish or container adapted to receive the perishable product. The lid comprises a rigid rim having a lower opening for receiving the dish, an impermeable elastic membrane whose peripheral section is connected or affixed to the rigid rim for sealing to the rim of the dish, and a valve-less air evacuator formed between the elastic membrane and the rim of the dish. The rigid rim is made from a sufficiently rigid material to prevent it from being deformed when the lid on the dish is being pressed. The valve-less air evacuator allows the air to flow out of the dish when the lid is being pressed and becomes closed when the lid is released to cause said lid to rebound and the space between said lid and container to expand to form a vacuum in the dish. To facilitate the removal of the lid, the device has a valve-less vacuum releaser comprising a finger-receiving chamber and a section of the elastic membrane located above the finger-receiving chamber and connected to the rigid rim for releasing the vacuum in the dish. The finger-receiving chamber is sufficiently large to allow a finger or finger-like member to pass through and push said elastic seal member to release the vacuum in the dish.
To prevent the sucking-in of the elastic membrane after microwave oven heating and prevent potential crushing of the perishable product in the dish or damaging of the elastic membrane during said sucking-in, at least one protruded section is provided on the elastic membrane or the rim of the dish to cause the lid to tilt sufficiently on the dish. To prevent the loss of vacuum in the dish during the storage of the perishable product in freezers and refrigerators, the elastic membrane is sufficiently thinned prior to being affixed to the rigid rim. In another embodiment of the invention, the elastic membrane may be replaced by a rigid or semi-rigid center section and an elastic seal member between the center section and the outer periphery of the rigid rim.
The present invention further provides a method for using the vacuum generating device by placing said lid on the dish containing a perishable product, forcing air out of the dish via an air evacuator formed between a section of the elastic membrane and the rim of the dish by pressing the lid, and releasing the lid to allow the space between said lid and dish to expand to form a vacuum therein. The method may further comprise releasing the vacuum by placing a finger into the finger-receiving chamber of the valve-less vacuum releaser and pushing the elastic membrane and restoring the lid's capability to generate and maintain vacuum in the dish after the lid is used one or more times by exposing the lid to a hot fluid having a temperature higher than 45° C. for a period of time.
The accompanying drawing illustrates diagrammatically non-limitative embodiment of the invention, as follows:
The rigid rim 24 comprises an outer rim 9 having a continuous channel 8 around its peripheral and an inner rim 10 having an upper ridge 11 receivable in channel 8 for sandwiching and affixing the periphery of the seal section 28 between the inner and outer rims. The outer rim 9 further has an upper horizontal ring 20, an upper opening 19 to allow access to the elastic membrane 28, and a bottom-facing inner perimeter 14. The inner rim further has a lower opening 22 to receive or surround the side wall 6 or rim 21 of the dish and a top-facing inner perimeter 15 that fits to the bottom-facing inner perimeter 14 of the outer rim to cause the outer seal section 28 to conform to the contour or topography of the bottom-facing inner perimeter 14 and top-facing inner perimeter 15. The outer rim 9 comprises a rigid material such as metal, glass, ceramics or hard plastics (e.g. polycarbonate, polyester, polyacrylate, polystyrene, polypropylene or polyamide) to lend strength to the elastic membrane 18 and to prevent the rigid rim 24 from deforming when the elastic membrane is pressed downward to the dish 2.
As shown in
To enable the sufficient closure of the valve-less air evacuator 16 after the release of the lid or elastic membrane, it was found that the ratio of the length (w) of the recessed section 14a or protruded section 15a along the inner perimeter of the rigid rim 24 to the height (h) of the recessed section 14a or protruded section 15a must be larger than 1. Preferably, the w/h ratio is larger than 5. For example, when h is 1 mm, w must be longer than 1 mm, preferably longer than 5 mm. A valve-less air evacuator with a w/h ratio smaller than 1 was found to cause the loss of the vacuum in dish 2 within days or even hours. It was also found that the thickness of the elastic membrane near the recessed section 17 should be less than about 0.05 inches, preferably less than 0.02 inches.
To allow the valve-less air evacuator to function, the maximum thickness allowed for the elastic membrane 18 was found to be 0.25 w or smaller. Long preservation (e.g. three to thirty weeks) of the vacuum in the dish 2 was found to be achieved when the elastic membrane 18 in the vacuum lid was thinner than about 0.01 inches. The elastic membrane 18 may be made from materials such as butyl rubber, nitrile rubber, ethylene acrylic elastomers, ethylene propylene (or EPDM) rubber, natural rubber, polyurethane elastomers, styrene-containing block copolymer elastomers, Santoprene elastomer and polychroroprene elastomer.
When using vacuum device 1, one puts the perishable product 5 into the dish 2, places the lid 7 onto the dish (
It is appreciated that without the valve-less evacuator 16, it would be difficult for air to flow out when the lid 7 is pressed and as result the dish 7 would have either very low vacuum or even no vacuum generated therein. The dish may be any container such as a bowl, platter, canister, can, drum, barrel, box, beaker, bottle or pot. The perishable product may be any product whose composition or physical property may be altered by air or the pollutant or particles in air. Such products include dry or wet foods, samples for analysis, chemicals, medicine, mechanical or electronic devices.
Because the device 1 of
Moreover, unlike the prior art devices that contain difficult-to-clean areas such as those in the valve openings or between the valve opening base and valve member, the food in the present device 1 can only contact the lower surface of the elastic membrane 18, which is easy to clean. The difficult-to-clean areas in the prior art devices may allow harmful bacteria to grow and contaminate the food stored therein. Therefore, the present vacuum device 1 provides much more hygienic alternative to the prior art vacuum seal devices.
One of the problems discovered with the present invention of the vacuum device in
To resolve the microwave induced sucking-in and crushed food problems, a heat activated venting valve (not shown) was initially attached to the elastic membrane 18 of the lid of
An improved version for the lid 7 of
By adding more mass to the right side of the rigid rim 24, the tilting of the lid 7 might be reversed to make the opening 27a taller and the opening 27b shorter. Such reversed tilting was discovered to be even more effective in preventing the elastic membrane 18 from being sucked in and the food 5 from being crushed. It was also found that it is possible to enable the lid 7 to tilt on the dish when there is only one protruded section 17a or 17b formed on the elastic membrane as long as the protruded section 17a is sufficiently large, e.g. larger than 20% of the area of the elastic membrane 18. It was further discovered that the microwave sucking-in of the elastic membrane 18 and the crushing of the food 5 might be prevented without tilting the lid 7 if the height h for the recessed section 14a in the device 1 of
When the dish 2 used in the device 1 of
When the lid 7 is pressed, the openings 27a and 27b become smaller but still remains sufficiently large (not shown) to allow air to flow out of the dish. The air in the annular chamber 82 is also pressed out through the opening 35, the vacuum facilitating opening 29 and the openings 27a and 27b. By making the w/h ratio larger than 1 and preferably larger than 5, the openings 27a and 27b are able to close right after releasing the lid. The elasticity of the gasket 3 tends to push the lid 7 upwards to expand the space between the lid and the dish, thus causing a vacuum to form therein. The closing of the openings 27a and 2b was found to be sufficient to preserve the vacuum up to several days and even weeks. Since the center section 79 of the lid is sufficiently rigid, this improved lid 7 is not susceptible to the microwave induced sucking-in and crushed food problems.
Another of the problems discovered with the present invention of the vacuum device 1 in
The valve-less vacuum releaser further has a squeeze enabler 42 formed above the section of elastic membrane 48. The squeeze enabler allows one to place one finger above the enabler and another finger of the same hand below the elastic membrane to squeeze the membrane to release the vacuum in the dish. The enabler 42 can be a thin plate connected to the rigid rim 24 as shown in
The vacuum relief valves in the vacuum food containers taught by the prior art and products such as the FoodSaver® or Seal-a-Meal® vacuum canisters have a small valve opening and a seal member that seals the valve opening during food storage and is manually moved away from the valve opening to release the vacuum prior to removing the lid. Similar to the air extraction valve used in the prior art products, such vacuum relief valves are susceptible to clogging, insufficient closing and bacteria growth problems. The valve-less vacuum releaser 43 has no such valve openings or seal member, and is thus immune to such problems during everyday home uses. It is appreciated that for the very low vacuum that forms in conventional sealed containers when refrigerated or in containers sealed by Amco or Progressive's silicone lids, the lid may be removed by just pushing up the rim or periphery of the lid. It is also appreciated that the valve-less vacuum releaser 43 may used for the lid for the vacuum food canisters and sealed containers.
During use, it was found that a much deeper vacuum was formed in the dish if the curved-out section 94 of the releaser is lifted or pushed upward slightly by a hand 44 while the elastic membrane 18 is being pressed into the dish by a hand or finger 25 (
A protruded section 57 is provided on the front part and another protruded section 57 on the back part of the rim 21 of the dish 2 to form openings 27a on the left and openings 27b on the right side of the protruded sections 57. Both the front and back protruded sections 57 are positioned near the right part of the dish to cause the lid 7 to tilt towards the left side to make openings 27b significantly larger than openings 27a for preventing the microwave induced sucking-in and crushed food problems discussed earlier for the device 1 of
Another of the problems discovered with the present invention of the vacuum device 1 in
It was found that after the lid 7 was used to generate and maintain vacuum in the container one or more times, the lid gradually lost its capability to generate and maintain sufficient vacuum for the perishable product. It was further found that the lid's capability to generate and maintain vacuum could be restored, at least partially, by exposing the lid to a hot fluid such as hot water having a temperature higher than 45° C. for about 10 seconds to several minutes. Higher hot fluid temperature up to 95° C. and longer exposing time was found to restore the lid's vacuum generating and maintaining capability in some cases more effectively.
It was discovered that although a vacuum lid 7 with its elastic membrane 18 thinned as much as 10% could maintain the vacuum in the dish 2 for several weeks to months in freezer or refrigerator, the same vacuum lid could not maintain the vacuum in the dish for more than one or two days in the same refrigerator or freezer after the dish covered by the vacuum lid was heated in microwave oven once or twice. It is believed that the microwave caused certain structural or compositional changes in the thinned elastic membrane 8 that is detrimental to the preservation of the vacuum between the dish 2 and the vacuum lid 7. Various protections for the elastic membrane, such as covering the elastic membrane by a plastic wrap films and even perforated aluminum foils, were found not effective in preventing such microwave-induced vacuum loss in the dish 2. It was discovered that the vacuum loss, however, could be prevented by thinning the elastic membrane more than 15%, preferably more than 25% before affixing the elastic membrane to the rigid rim 24.
The scope of the invention is obviously not restricted or limited to the embodiments described by way of examples and depicted in the drawings, there being numerous changes, modifications, additions, and applications thereof imaginable within the purview of the claims.
Claims
1. A vacuum generating device for sealing a perishable product comprising:
- a lid for a container adapted to receive the perishable product, said lid comprising a center section substantially impermeable to air to prevent air from permeating through into the container, a rigid rim located around said center section for receiving or surrounding the container, said rigid rim comprising a sufficiently rigid material to prevent it from being substantially deformed when said lid on the container is being pressed, and an elastic seal member connected or affixed to said rigid rim for forming an airtight seal to the rim of the container,
- a valve-less air evacuator formed between a section of said seal member and the rim of the container, said valve-less air evacuator allowing the air to flow out of the container when said lid is being pressed and becoming closed when said lid is released to cause said lid to rebound and the space between said lid and container to expand to form a vacuum in the container; and
- whereby in use, said lid is pressed to cause the air to flow out of the container via said valve-less air evacuator and is subsequently released to form said vacuum to cause the closing of said valve-less air evacuator, thereby preserving said vacuum for the perishable product in the container for an extended period of time.
2. A vacuum generating device as defined in claim 1 wherein said valve-less air evacuator comprises a portion of said seal member that is sufficiently more deformable than the rest of said seal member to enable an air passage to form between said portion of said seal member and the rim of the container as said lid is being pressed and that is sufficiently elastic to stamp out said air passage when said lid is released to form said vacuum.
3. A vacuum generating device as defined in claim 1 wherein said seal member comprises an elastic membrane attached or affixed to said rigid rim, said elastic membrane having a lower surface for sealing to the rim of the container and an upper surface.
4. A vacuum generating device as defined in claim 3 wherein said elastic membrane comprises a section having a lower tension force than the rest of said elastic membrane to form said valve-less air evacuator between said lower tension section of said elastic membrane and the rim of the container.
5. A vacuum generating device as defined in claim 1 wherein said valve-less air evacuator comprises at least one of a protruded section and a recessed section for said seal member to form at least one opening between said seal member and the rim of the container to allow air to flow out of the container as said lid is being pressed, said seal member being sufficiently elastic and flexible to stamp out said at least one opening upon release of the lid to form said vacuum.
6. A vacuum generating device as defined in claim 5 wherein the width (w) to height (h) ratio w/h of said at least one of a protruded section and a recessed section is larger than 4.
7. A vacuum generating device as defined in claim 6 wherein the maximum thickness of said seal member allowed for said valve-less air evacuator to work is 0.25 times of the width (w) of said at least one of a protruded section and a recessed section.
8. A vacuum generating device as defined in claim 5 wherein said seal member and center section of said lid comprise an elastic membrane, the periphery of said elastic membrane being attached or affixed to said rigid rim.
9. A vacuum generating device as defined in claim 8 wherein said at least one of a protruded section and a recessed section is formed by providing at least one of a protrusion and a recession along the inner perimeter of said rigid rim and by connecting or affixing said elastic membrane to said rigid rim in such a way that the outer part of said elastic membrane conforms to the contour of said inner perimeter of said rigid rim.
10. A vacuum generating device as defined in claim 8 wherein said rigid rim has a first rim having a recession along its inner perimeter and a second rim having a protrusion receivable in said recession of said first rim, said first and second rims being adapted to sandwich and affix the peripheral part of said elastic membrane between said first and second rims to form said at least one of a protruded section and a recessed section.
11. A vacuum generating device as defined in claim 8 wherein said at least one of a protruded section and a recessed section is sufficiently wide and high to make said at least one opening between said elastic membrane and the rim of the container sufficiently large to prevent the sucking-in of said elastic membrane after microwave oven heating, thereby preventing potential crushing of the perishable product in the container or damaging of the elastic membrane during said sucking-in.
12. A vacuum generating device as defined in claim 1 wherein said center section and seal member of said lid comprise an elastic membrane and, wherein said valve-less air evacuator comprises a sufficiently large protruded or recessed section for said elastic membrane to form a sufficiently large air passage between the container's rim and said elastic membrane to prevent the sucking-in of said elastic membrane after microwave oven heating, thereby preventing potential crushing of the perishable product in the container or damaging of the elastic membrane by said sucking-in.
13. A vacuum generating device as defined in claim 1 wherein said center section and seal member of said lid comprise an elastic membrane and, wherein said valve-less air evacuator comprises at least one protruded section adapted to cause said lid to tilt sufficiently on said container to prevent the sucking-in of said elastic membrane after microwave oven heating, thereby preventing potential crushing of the perishable product in the container or damaging of the elastic membrane during said sucking-in.
14. A vacuum generating device as defined in claim 1 wherein at least said seal member of said lid comprises an elastic membrane, said elastic membrane being substantially thinned prior to being attached or affixed to said rigid rim to prevent the loss of vacuum in the container during an extended period of storage.
15. A vacuum generating device as defined in claim 1 further comprising a valve-less vacuum releaser for releasing the vacuum in the container, thereby allowing the removal of said lid, said releaser being sufficiently large to allow a finger or finger-like member to reach and push said seal member away from the rim of the container to produce a passage for air to enter the container.
16. A vacuum generating device for sealing a perishable product comprising:
- a center section substantially impermeable to air to prevent air from permeating into the container;
- a rim connected or adapted to connect to said center section and comprising a sufficiently rigid material adapted to prevent said rim from being substantially deformed when a force or pressure is applied to said center section;
- an elastic seal member connected or adapted to connect to said rim for forming an airtight seal to the container, and
- a valve-less air evacuator comprising a release section of said elastic seal member for controlling air flow without a valve, said valve-less air evacuator being adapted to form an air passage between said release section and the container to allow air to flow out of the container when at least one of a force, pressure and vacuum is applied to said device to remove air from the container and to close said air passage when said at least one of said force, pressure and vacuum is removed, thereby sealing the container and preserving the vacuum therein.
17. A vacuum generating device as defined in claim 16 wherein said release section is adapted to be more deformable than at least some other part of said elastic member affixed to said rim to enable said air passage to form between said release section and the container.
18. A vacuum generating device as defined in claim 16 wherein said release section is adapted to have lower tension than at least some other part of said elastic membrane to allow said air passage to form between said release section and the container.
19. A vacuum generating device as defined in claim 16 wherein said elastic seal member is sufficiently stretched during the assembly of said device to reduce the thickness of said seal member and maintain said member in a stretched condition before said elastic seal member is sealed to the container, thereby improving the vacuum seal for the perishable product.
20. A vacuum generating device as defined in claim 16 wherein said center section and elastic seal member comprise an elastic membrane that is sufficiently stretched to reduce its thickness by at least 3% and affixed to said rim to keep said elastic membrane in a stretched condition under tension when said device is not in use or not applied to the container.
21. A vacuum generating device as defined in claim 16 wherein said rim comprises a first rigid rim and a second rim, wherein during the assembly said elastic membrane is sandwiched between said first and second rims and stretched to reduce its thickness by at least 3% as compared with the original thickness of the elastic membrane in its original non-stretched condition prior to the assembly.
22. A vacuum generating device as defined in claim 16 wherein said elastic seal member has a first section for sealing to the container and a second section connected to a part of said first section and extending out of the container, wherein said rim comprises at least one of an outwardly protruding section and inwardly receding section, said device further comprising a valve-less vacuum releaser including said second section and said one of said outwardly protruding and inwardly receding sections, wherein said second section of said seal member is defined by said one of said outwardly protruding and inwardly receding sections and is smaller than said first section but enough large to allow a finger-like member or finger to push said elastic membrane away from the container to release the vacuum therein.
23. A vacuum generating device as defined in claim 16 further comprising a valve-less vacuum releaser having at least one of a beam and a plate connected to said rigid rim and extending over a section of said elastic membrane to facilitate the release of the vacuum in the container.
24. A vacuum generating device as defined in claim 16 further comprising a valve-less vacuum releaser comprising an annular ring or ridge extending inwardly and spaced above said elastic membrane.
25. A method for using a vacuum generating device to seal a perishable product comprising a lid for a container adapted to receive the perishable product, said lid comprising a center section substantially impermeable to air to prevent air from permeating through into the container, a rigid rim located around said center section for surrounding the container, said rigid rim comprising a sufficiently rigid material to prevent said rigid rim from being substantially deformed when said lid on the container is pressed, an elastic seal member connected to said rigid rim for sealing to the rim of the container, and an air evacuator formed between a section of said seal member and the rim of the container, said method comprising:
- placing said lid on the container containing a perishable product;
- forcing air out of the container via said air evacuator between said section of said elastic seal member and the rim of the container by pressing said lid on the container; and
- releasing said lid to allow the space between said lid and container to expand to form a vacuum therein.
26. A method as defined in claim 30 further comprising a step of lifting a portion of said rigid rim slightly during said step of forcing air out of the container and a step of letting said portion of said rigid rim down prior to said step of releasing said lid, thereby producing a deeper vacuum in said container.
27. A method as defined in claim 30 wherein said seal member comprise an elastic membrane having a peripheral section affixed to said rigid rim, said method further comprising a step of exposing said lid to a hot fluid having a temperature higher than 45° C. for a period of time to restore said lid's capability to generate and maintain vacuum in the container after said lid is used one or more times.
28. A method as defined in claim 30 wherein said device further comprises a valve-less vacuum releaser for releasing the vacuum in the container, said valve-less vacuum releaser comprising one of an outwardly protruded section extending at least partially horizontally from said rigid rim of said lid and an inwardly recessed section extending at least partially horizontally from the rim of the container and a section of said elastic seal member located within said one of said outwardly protruded and inwardly recessed sections, said method further comprising a step of pushing said section of said elastic seal member away from the rim of the container by a finger or finger-like member receivable in said one of said outwardly protruded and inwardly recessed sections to release the vacuum therein.
Type: Application
Filed: Sep 22, 2009
Publication Date: Jan 28, 2010
Inventor: Edward Z. Cai (Camas, WA)
Application Number: 12/586,453
International Classification: B65B 31/04 (20060101);