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Title:
VACUUM GENERATING DEVICE FOR SEALING PERISHABLE PRODUCTS AND METHOD OF USE
Document Type and Number:
WIPO Patent Application WO/2008/018992
Kind Code:
A2
Abstract:
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 which 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.

Inventors:
CAI EDWARD Z (US)
Application Number:
PCT/US2007/016755
Publication Date:
February 14, 2008
Filing Date:
July 26, 2007
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CAI EDWARD Z (US)
International Classes:
B65D51/16; B65D43/04
Foreign References:
US91701604A2004-08-12
US6557462B12003-05-06
US3559843A1971-02-02
US3901405A1975-08-26
US4051971A1977-10-04
US5871120A1999-02-16
US6148875A2000-11-21
US6194011B12001-02-27
Other References:
See also references of EP 2046656A4
Attorney, Agent or Firm:
CAI, Edward, Z. (Camas, WA, US)
Download PDF:
Claims:

What is claimed is:

1. A vacuum generating device for sealing a perishable product comprising: a lid for a container adapted to receive the perishable product, said Hd 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 Hd to rebound and the space between said lid and container to expand to form a vacuum in the container; and whereby in use, said Hd 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 at least one portion of said seal member that is sufficiently more defoπnable or weaker than other part of said seal member when connected to said rigid rim 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 Hd 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 S 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 S 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 Hd 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 port 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 as defined in claim 1 wherein said valve-less air evacuator comprises at least one portion of said seal member that is sufficiently more defoπnable or weaker at one direction man at another direction to enable an air passage to form between said portion of said seal member and the rim of the container as said Hd is being pressed and that is sufficiently elastic to stamp out said air passage when said Hd is released to form said vacuum.

17. A vacuum generating device for sealing a perishable product comprising:

a Hd for a container adapted to receive the perishable product, said Hd comprising an elastic seal member for forming an airtight seal to the rim of the container, said elastic seal member being substantially impermeable to air to prevent air from permeating through into the container, and a rigid rim connected to said elastic seal member for receiving or surrounding the rim of the container, said rigid rim comprising a sufficiently rigid material for preventing said rigid rim from being substantially deformed when said lid is pressed to deform said elastic seal member to force air out of the container and for forming and preserving vacuum in the container after said lid is released; a valve-less vacuum releaser for releasing the vacuum in the container to facilitate the removal of said Hd, said valve-less vacuum releaser comprising a finger-receiving chamber and a section of said elastic seal member located above said finger-receiving chamber and connected to said rigid rim, said finger-receiving chamber being 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 container; and

whereby in use, to form a vacuum in the container one presses said lid to force the air out of the container and subsequently releases said Hd 1 and to open the container one places a finger or finger-like member into said finger-receiving chamber and pushes said elastic seal member to release said vacuum in the container.

18. A vacuum generating device as defined in claim 17 wherein valve-less vacuum releaser further comprises a squeeze-enabler connected to said rigid rim and located a predetermined distance above said section of said elastic seal member, thereby enabling one to place a finger on said squeeze-enabler and another finger in said finger-receiving chamber underneath said elastic membrane and to squeeze to release the vacuum in the container.

19. A vacuum generating device as defined in claim 17 wherein valve-less vacuum releaser further comprises a curved-out section on said rigid rim for defining said finger-receiving chamber below said section of said elastic seal member.

20. A vacuum generating device as defined in claim 17 wherein said finger-receiving chamber is formed by curving inward or recessing a section of the side wall of the container.

21. A vacuum generating device as defined in claim 17 wherein said finger-receiving chamber comprises a first finger-receiving chamber formed in a handle connected to the side wall of said container and a second finger-receiving chamber formed within said lid and located below said section of said elastic seal member.

22. A vacuum generating device as defined in claim 17 wherein said elastic seal member comprises an elastic membrane having a peripheral section affixed to said rigid rim.

23. A vacuum generating device for sealing a perishable product comprising: a lid for a container adapted to receive a perishable product, said lid comprising an elastic membrane for sealing to the rim of the container, said elastic membrane being substantially impermeable to air to prevent air from permeating through into the container, and a rigid rim connected to the peripheral section of said elastic membrane, said rigid rim comprising a sufficiently rigid material to prevent it from being substantially deformed when said elastic membrane is pressed into the container to force the air out of the container, and wherein said elastic membrane is sufficiently thinned prior to being connected or affixed to said rigid rim to prevent the loss of vacuum in the container during the storage of said perishable product.

24. A vacuum generating device as defined in claim 23 wherein said elastic membrane is thinned at least 4 % prior to being connected or affixed to said rigid rim to prevent the loss of vacuum.

25. A vacuum generating device as defined in claim 23 wherein said elastic membrane is thinned at least IS % to prevent said lid from losing its capability in preserving the vacuum in the container after said lid is used to cover a container to heat the perishable product in microwave oven at least once.

26. 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 Hd to allow the space between said Hd and container to expand to form a vacuum therein.

27. A method as defined in claim 26 wherein said device further comprises a valve-less vacuum releaser having a finger-receiving chamber and a section of said elastic seal member located above said chamber, said method further comprising a step of placing a finger or finger-like member into said finger-receiving chamber and pushing said elastic seal member to release the vacuum in the container.

28. A method as defined in claim 26 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.

29. A method as defined in claim 26 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 Hd 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.

Description:

Vacuum Generating Device for Sealing Perishable Products and Method of Use

Field of die Invention

This invention relates to a vacuum generating device for perishable products such as food, and is an improvement for the applicant's US Patent Application Serial # 10/917,016.

Background of the Invention

In 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 Hd via a vacuum tube as taught by FoodSaver 8 or Seal-a-Meal ® sealer or by manually removing air via a check valve in the Hd as taught by Wang in US Patent No. 6,557,462. Such vacuum containers are susceptible to air leakage and plugging of the check valve and vacuum release valve in the Hd 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 US Patent Application Serial # 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 Invention

The invention provides a vacuum sealing device having a Hd for a dish or container adapted to receive die 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 Hd 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 Hd is released to cause said Hd to rebound and the space between said Hd and container to expand to form a vacuum in the dish. To facilitate the removal of the Hd, 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 die rigid rim for releasing the vacuum in die 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 Hd 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 Hd 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 Hd 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.

Description of the Drawing

The accompanying drawing illustrates diagrammaticalh/ non-limitative embodiment of the invention, as follows:

FIG. 1 is a section view of a vacuum generating device having a vacuum lid on a dish before the vacuum is formed;

FIG. Ia is a section view for the upper part of the device along line A-A of FIG. 1;

FIG. Ib is a section view of the device along line B-B of FIG. 1;

FIG. Ic is a section view of the device of FIG. 1 when the lid is being pressed by a hand or finger,

FIG. Id is a section view of the device of FIG. Ic after releasing the Hd;

FIG.2 is a section view of a first modified version for the device of FIG. 1;

FIG.2a is a section view for the upper part of me device along line A-A of FIG.2;

FIG.2b is a section view of the upper part of the device of FIG.2 when the lid tins naturally on the dish;

FIG. 3 is a section view of a device having a vacuum Hd on a dish before the vacuum is formed according to a second embodiment of the invention;

FIG. 3a is a section view of the upper part of die device of FIG.3 when the lid is being pressed by a hand or finger;

FIG.3b is a section view of die device of FIG. 3a after releasing the lid;

FIG.4 is a section view of a first modified version for the device of FIG. 3, showing the modified vacuum Hd and die upper part of the dish before die vacuum is formed;

FIG. S is a section view of a second modified version for the device of FIG. 3;

FIG. Sa is a section view for die upper part of die device along line A-A of FIG. S;

FIG. Sb is a section view of die upper part of die device of FIG. S when die lid tilts naturally on die dish;

FIG. Sc is a section view of die device of FIG. S after the lid is pressed by a hand or finger and released;

FIG.6 is a section view of a device having a vacuum lid on a dish before die vacuum is formed according to a third embodiment of die invention;

FIG. 6a is a section view of die device along line A-A of FIG. 6;

FIG. 6b is a section view of die upper part of die device of FIG. 6 when die lid is being pressed by a hand or finger,

FIG. 6c is a section view of die device of FIG. 6b after releasing die lid;

FIG. 7 is a section view of a device having a vacuum lid above a dish before a vacuum is formed according to a forth embodiment of die invention;

FIG. 7a is a section view of die device along line A-A of FIG. 7;

FIG. 7b is a section view of die device along line B-B of FIG. 7;

FIG. 7c is a section view of die device of FIG. 7 after die Hd is pressed by a hand or finger and released;

FIG. 8 is a section view of a device having a vacuum Hd on a dish before a vacuum is formed according to a fifth embodiment of die invention;

FIG.8a is a section view of the device along line A-A of FIG. 8 without showing die food in die dish;

FIG. 8b is a section of die device of FIG. 8 when die lid is being pressed by a hand or finger;

FIG. 8c is a section view of the device of FIG. 8b after releasing die Hd;

FIG.9 is a section view of the outer rigid rim, inner rim and die membrane of die Hd of Fig. 8 before affixed between die upper and lower rigid rims;

FIG.9a is a section view of die outer rigid rim, inner rim and die membrane that is being thinned about 30% to prevent loss of vacuum;

FIG.9b is a section view of die upper rigid rim, inner d rim and die thinned membrane after die thinned membrane is affixed between die outer and inner rims;

Detailed Description of fee Preferred Embodiments

Figs. Mb show a vacuum generating device 1 having a vacuum lid 7 and a dish 2. The dish has a side wall 6, rim 21, bottom 4 and chamber 3 for receiving food S. Lid 7 has an elastic and air impermeable membrane 18 having an outer seal section 28, a rigid rim 24 for adding strength to the elastic membrane 18 and enabling the membrane to generate vacuum in dish 2, and a valve-less air evacuator 16 formed between the seal section 28 and the rim 21 of dish 2 for releasing the air in the dish when the lid is being pressed and for causing the seal section 28 to seal to the rim 21 to prevent air from entering the dish when the lid is released.

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 IS mat 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 IS. The outer rim 9 comprises a rigid material such as metal, glass, ceramics or hard plastics (e.g. polycarbonate, polyester, polyacrylate, polystyrene, polypropylene or poryamide) 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 Figs. 1, 1a and Ib, the valve-less air evacuator 16 comprises a recessed section 14a on the bottom-facing inner perimeter 14 of the outer rim 9 and a protruded section ISa on the bottom-facing inner perimeter IS of the inner rim 10 receivable in the recessed section 14a to form a recessed section 17 on the seal section 28 of the lid. The recessed section 17 originates from the recessed section 14a and protruded section 15a of the rigid rim 24 and extends a distance L into the seal section 28 of the elastic membrane 18 to form an opening 27 between the recessed section 17 and the rim 21 of the dish 2. The opening 27 stays partially open when the Ud or elastic membrane is pressed downward by a finger or hand 25 (Fig. Ic) to allow air to flow out of the dish. Upon release, the lid or elastic membrane tends to rebound, thus causing the space between the lid and dish to expand and a vacuum to form in the dish. The valve-less air evacuator is self closed to enable sufficient closing of the opening 27 to preserve the vacuum in the dish for an extended period of time (Fig. Id).

To enable the sufficient closure of the valve-less air evacuator 16 after the release of the Hd or elastic membrane, it was found that the ratio of the length (w) of the recessed section 14a or protruded sectionlSa along the inner perimeter of the rigid rim 24 to the height (h) of the recessed section 14a or protruded section ISa 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 man 1 mm, preferably longer than S mm. A valve-less air evacuator with a w/h ratio smaller man 1 was found to cause the loss of the vacuum in dish 2 within days or even hours. It was also found mat the thickness of the elastic membrane near the recessed section 17 should be less than about 0.05 inches, preferably less man 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 0.2Sw 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, nitrite rubber, ethylene acrylic elastomers, ethylene propylene (or EPDM) rubber, natural rubber, polyurethane elastomers, styrene-containing block copolymer elastomers, Santoprene elastomer and poiychroroprene elastomer.

When using vacuum device 1, one puts the perishable product S into the dish 2, places the Hd 7 onto the dish (Fig. 1), and presses the lid or elastic membrane 18 by hand or finger 25 to evacuate the dish (Fig. Ic) through the valve-less air evacuator 16. Although the valve-less air evacuator is reduced in size by the pressing of the Hd, it is still sufficiently large for air to flow out (Figs. 1 and Ic). By making the w/h ratio larger than 1 and preferably larger than 4, the valve-less evacuator is able to close right after releasing the lid. After the Hd is released or not pressed, the elasticity of the elastic membrane tends to cause the lid 7 to move 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 weeks and even months.

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 Fig. 1 enables a consumer to produce a vacuum seal by simply pressing the elastic membrane 18, it not only saves consumers the money to buy expensive vacuum seal appliances but also make the vacuum sealing of food significantly faster and simpler. More importantly, since device 1 evacuates air via valve-less air evacuator 16 between the elastic membrane 18 and the rim 21 of the dish, it does not need any valves for extracting or removing air from the dish as taught in prior art vacuum devices by Saleri et al. in US Patent 4,051,971, Romero et al. in US Patent 5,871,120, Breen in US Patent 6,148,875,Glaser in US Patent 6,194,011 and Wang in US Patent No. 6,557,462. Such air extraction or removal valves in the prior art vacuum devices comprise a valve opening and a movable valve member mat are susceptible to clogging by the solids in food and soup and to insufficient closing of the valve opening by the movable valve member. The valve-

Si BSTITXTF. SHEET (RULE 26)

less air evacuator, which replaces the air extraction valve in the prior art, has no valve opening or movable valve member and is directly formed on the rim of the dish 2. As a result, the valve-less air evacuator is cleaned every time when the dish is washed, and is thus much less susceptible to clogging or to insufficient closing than the prior art vacuum devices.

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 Fig. 1 is that after heating the device containing food in microwave oven, the elastic membrane 18 of the lid 7 is sometimes completely sucked into the dish 2 and crashed the food therein. In case that the food contains sharp bones or shells, the elastic membrane was found to be weakened or even punctured by the food. The complete sucking-in of the elastic membrane also made it very difficult to remove the lid from the dish 2 after the microwave heating. Such microwave induced sucking-in and crushed food problems were found to occur when the lid 7 was not promptly removed from the dish after the microwave oven heating.

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 Ud of Fig. 1. The venting valve has a valve opening in communication with a punched opening (not shown) on the elastic membrane and a bi-metal plate that normally seals the valve opening. When the food in the device 1 was heated up, the bi-metal plate deformed and opens up the valve opening to vent the dish. The bi-metal plate remained in the deformed state to vent the dish after microwave heating, thus preventing the elastic membrane from being sucked into the dish and from crashing the food. Unfortunately, the venting valve was frequently found to be clogged or to cause loss of vacuum due to leakage when the food contains soup or liquid.

An improved version for the lid 7 of Fig. 1 is provided (Figs. 2, 2a and 2b) to resolve the microwave induced sucking-in and crushed food problems. In the improved Hd 7, the valve-less air evacuator 16 comprises a first protruded section 14a on the bottom-facing inner perimeter 14 of the outer rim 9 and a first recessed section ISa on the top-facing inner perimeter IS of the inner rim 10 receivable in the first protruded section 14a to form a first protruded section 17a on the elastic membrane 18 and a second protruded section 14b on the bottom-facing inner perimeter 14 and a second recessed section ISa on the top-facing inner perimeter IS receivable in the second protruded section 14a to form a second protruded section 17a on the elastic membrane (Figs.2 and 2a). The

protruded sections 17a and 17b originate from the protruded sections 14a and 14b of the rigid rim 24, respectively and extends a distance L into the seal section 28 of the elastic membrane 18 to form openings 27a and 27b between the rim 21 of the dish 2 and die part of die seal section 28 that is lifted up by the two protruded sections 17a and 17b. Since the first and second protruded sections 17a and 17b on die seal section 28 of the elastic membrane are located at die left side of the lid, die lid tends to tilt naturally when placed on die dish 2 (Fig.2b). It was found that such tilting of die Hd on die dish prevented die elastic membrane from being sucked into die dish and die food from being crashed after microwave oven heating. It is believed that die tilting of die lid 7 on die dish made die opening 27b tall enough to prevent die elastic membrane from being sucked into die dish after microwave oven heating.

By adding more mass to die right side of die rigid rim 24, die tilting of die Hd 7 might be reversed to make die opening 27a taller and die opening 27b shorter. Such reversed tilting was discovered to be even more effective in preventing die elastic membrane 18 from being sucked in and the food S from being crushed. It was also found mat it is possible to enable die Hd 7 to tilt on die dish when diere is only one protruded section 17a or 17b formed on me elastic membrane as long as die protruded section 17a is sufficiently large, e.g. larger than 20% of die area of die elastic membrane 18. It was further discovered mat die microwave sucking-in of me elastic membrane 18 and die crushing of die food S might be prevented widiout tilting die lid 7 if die height h for die recessed section 14a in die device 1 of Fig. 1 is larger man 0.S mm, preferably larger dian 1 mm. However, die tilting of die Hd 7 was found to be several times more effective against die microwave induced sucking-in and crushed food problems than a deeper or taller recession 14a. After all, die recession 14a can not be too deep or tall to make die valve-less air evacuator 16 difficult to close. It was die noticed that when die height h of die recessed section 14a became larger man S to 10 mm die valve- less evacuator became much less capable, if not incapable, to close to preserve die vacuum formed by die Hd 7 in die dish.

When die dish 2 used in die device 1 of Fig. 1 or 2 is substantially smaller tiian die lid 7, it was found tiiat to enable die Hd to tilt (Fig.2b) or make die recessed section 14a (Fig. 1) taller tiian 0.S mm is not sufficient to resolve me microwave induced suck-in and crushed food problems. To prevent die sucking-in and crushed food problems when a smaller diameter dish 2 is used, it was found that die lengm w of die protruded or recessed section 14a should be about 1/32, preferably 1/8, of die perimeter of die Ud 7.

Figs. 3, 3a and 3b provide a second improved version of die Ud 7 of Fig. 1 tiiat has a sufficiently rigid center section 79 to prevent die sucking-in and crashed food problems after microwave oven heating. The elastic membrane 18 adopts a ring shape. The inner and outer peripheries of die ring-shaped elastic membrane are attached to die inner rim 10 and outer rim 9, respectively, to form a ring-shaped seal section 28 below die chamber 31 between die inner and outer

rims. The valve-less air evacuator 16 comprises a portion 81 of the ring-shaped seal section 28. The elastic membrane in the portion 81 is thinner or easier to stretch, i.e. more stretchable, than the elastic membrane in the rest of die ring-shaped seal section 28. A vacuum facilitating opening 29 is formed on die outer rim 9 for venting the chamber 31 to facilitating the formation of vacuum in the dish 2. Before the lid 7 is pressed, the valve-less air evacuator 16 is closed and there is no gap between the portion 81 of the seal section 28 and the rim 21 of the dish (Fig. 3). When the lid is pressed by a hand or finger 25, the seal section 28 is pushed into the chamber 31 and the air pressure in the dish pushes the thinner or weaker elastic membrane at the portion 81 away from the rim 21 of the dish to form the opening 27 to allow air to flow out of the dish (Fig. 3a). The opening 29 lets air out of the chamber 31 to prevent any air pressure to form above the elastic membrane 18. After die lid is released, die elastic membrane 18 tends to return to its natural position, thus causing the space between the lid and dish to expand to form a vacuum and causing the elastic membrane in the portion 81 to seal to the rim 21 of the dish (Fig. 3b). Besides lowering the thickness or increasing the stretchability of the elastic film on the portion 81 to produce the valve-less air evacuator 16 when pressing the lid, it was found that providing a recessed or protruded portion on Ae seal section 28 like that in Figs. 1 and 2 also produced the valve-less air evacuator. In all cases, since elastic membrane 18 is confined by the chamber 31 and the center section 79 of the lid is sufficiently rigid, mis improved lid 7 is not susceptible to the microwave induced sucking-in and crushed food problems.

Fig.4 provides a first modified version to the lid 7 of Fig.3 that has a sufficiently rigid center section 79 to prevent the microwave induced sucking-in and crashed food problems after microwave oven heating. In this lid, the elastic membrane is replaced by a U-shaped seal gasket 32 received in the annular chamber 31. The seal gasket comprises an annular bottom seal section 28, an annular empty chamber 82, and a valve-less air evacuator 16 having an easy-to-compress neck section 34. An opening 35 is formed on the side wall of the gasket 32 in communication with the vacuum facilitating opening 29 to facilitate the compression of the seal gasket. When the Hd 7 is pressed, the neck section 34 allows an opening 27 (not shown) to form between the rim 21 of dish 2 and the part of the seal section 28 located below neck section to allow air in the dish to exit. Since the center section 79 of the lid is sufficiently rigid, this improved lid 7 is also not susceptible to the microwave induced sucking-in and crushed food problems.

Figs. S-Sc provide a second modified version to the Hd 7 of Fig. 3 that has a sufficiently rigid center section 79 to prevent the sucking-in and crashed food problems after microwave oven heating. In this alternative Hd, the elastic membrane 18 is also replaced by a U-shaped seal gasket 32 received in the annular chamber 31. The seal gasket comprises an annular bottom seal section 28, an annular empty chamber 82, a opening 35 in communication with the vacuum facilitating opening 29, and a valve-less air evacuator 16 comprising two protruded sections 77, each having a length w and a height h, on the seal section 28. The two protruded sections 77 shs on the rim 21 of die dish and causes two

openings 27a and 27b to form between the seal section 28 and the rim 21 (Figs. S and Sa). The two protruded sections 77 are off centered and located near the right side of the lid, causing Ae lid to tilt naturally towards the left side on the dish 2 (Fig. Sb). It was found that such tilting of the lid on the dish prevents the damage of the lid and the breakage or deformation of the dish after the dish containing wet food is heated in microwave oven.

When the lid 7 is pressed, the openings 27a and 27b become smaller but still remain 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 S, 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 unproved Hd 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 Fig. 1 is that the lid 7 is difficult to be removed from the dish 2, especially when most of the air in the dish is removed or expelled. Such difficurt-to-remove Hd problem was found to be inconvenient to the users. It was also found to cause spill and mess when one tries very hard to remove the Ud from a dish that contains soup or other liquid. In case of hot soup, the spill might reach a user's hand and cause potential burning or hutting. Figs.6, 6a, 6b and 6c describe a valve-less vacuum releaser 43 for the device 1 to resolving this problem. The releaser 43 comprises a curved-out section 94 on the rigid rim 24, a section of elastic membrane 48 affixed to the curved-out section, and a finger receiving chamber 47 defined by the curved-out section below the section of elastic membrane 48. The finger receiving chamber 47 is large enough to receive a finger or a finger-like member 41 (Fig. 6c) to enable the finger to push the elastic membrane upward to generate an air passage for releasing the vacuum. The vacuum release by the finger 41 makes the removal of the lid 7 from the dish spill-free and much less difficult.

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 Fig. 6 or one or more beams (not shown) connected to the rigid rim. It is important the squeeze enabler is positioned sufficiently apart from the section of elastic membrane 48. The distance between the elastic membrane and the enabler should be more than about 2 mm, and is preferably more than 4 mm or 0.16 inches.

The vacuum relief valves in the vacuum food containers taught by the prior art and products such as the FoodSaveτ®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 Ud 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 (Fig.6b). It is appreciated that the valve-less vacuum releaser 43 can also be formed on the vacuum lid 7 of the device 1 described in Figs.3 to S. The curved-out section 94 of the releaser 43 is formed on the out rim 9 of the annular chamber 31 and the ring-shaped or annular seal section 28 is extended into the curved-out section 94 to form an elastic section 48 affixed to the curved-out section 94 (not shown).

Figs. 7, 7a, 7b and 7c describe a first modified version of the valve-less vacuum releaser 43 for the vacuum lid 7. The device I has a rectangular dish 2 and a rectangular vacuum lid 7 having a rectangular elastic membrane 18 affixed to the rigid rim 28 of the lid and two valve-less vacuum releasers 43, one on the left and the other on the right side of the lid. The lower opening 22 of the lid 7 is dimensioned to receive the rim 21 and the two handles 49 of the dish 2. Each valve-less vacuum releaser 43 comprises a first finger-receiving chamber 47b in a handle 49 of the dish 2, a section of elastic membrane 48 above the first finger-receiving chamber 47b, a second finger-receiving chamber 47a below the section of elastic membrane 48 in the lid 7, and squeeze enabling plate 42. The squeeze plate 42 is located a predetermined distance above the upper horizontal ring 20 formed on the outer rim 9 (Fig. 7 and 7b). The first finger-receiving chamber 47b has an inner chamber 52 and an outer opening 51 (Fig. 7a) sufficiently large to allow a finger 41 to pass through to reach the second finger-receiving chamber 47a and the section of elastic membrane 48 to push the elastic membrane to release the vacuum in the dish (Fig. 7c).

Figs. 8, 8a, 8b and 8c describe a second modified version of the valve-less vacuum releaser 43 for a round vacuum lid 7 comprising a round elastic membrane 18 with its peripheral section 28 affixed to the rigid rim 24 similar to mat described in Fig. 1. The valve-less vacuum releaser 43

comprises a finger-receiving chamber 47 formed by curving or recessing me side wall 6 of the dish 2 and the section of elastic membrane 48 above the finger receiving chamber (Figs. 8 and 8a). The chamber 47 is sufficiently large to receive a finger or finger-like member 41 to allow the finger to push the section of elastic membrane 48 to release the vacuum in the dish (Fig. 8c). In mis preferred embodiment, the part of the upper horizontal ring 20 located a predetermined distance above the section of elastic membrane 48 could function as the squeeze enabler 43 to facilitate the release of the vacuum in the dish 2.

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. Bom 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 Fig. 1. The openings 27a and 27b also functions as the valve-less air evacuator 16 mat enables air in the dish to be evacuated when a hand or finger 25 presses the elastic membrane 18 of the lid into the dish (Fig. 8b) and enable sufficient closing of the openings 27a and 27b after releasing die lid to preserve the vacuum formed in the dish 2 (Fig. 8c).

Another of the problems discovered with the present invention of the vacuum device 1 in Fig. 1 is the loss of vacuum in the dish 2 after an extended period of storage in freezer and refrigerator. Such loss of vacuum was initially thought due to the presence of the valve-less air evacuator 16. Later studies found that the vacuum disappeared in several days and sometimes in half a day even if the valve-less air evacuator was intentionally removed from the device 1. Such vacuum loss in the dish was found to occur with various elastic membranes such as butyl rubber, ethylene acrylic elastomers, ethylene propylene (or EPDM) rubber, polyurethane elastomers and natural rubber membranes. Although the reason for such vacuum loss was still not understood, it was discovered, quite by accident, that if the elastic membrane 18 was thinned about 12% compared to the membrane's original thickness, the loss of vacuum in the dish 2 was prevented or at least significantly reduced, hi several long-term storage tests, it was found that the vacuum lid 7 comprising an elastic membrane 18 that was thinned about 12% could maintain the vacuum in the dish for six months to a year. In comparable tests with the same elastic membrane but with the membrane not thinned in the vacuum Hd 7, the vacuumed in the dish 2 lasted only several days.

Figs.9a-c shows the thinning process for the elastic membrane 18 before affixing it to the rigid rim 24. Before the thinning, the elastic membrane 18 was thick and its peripheral edge was clamped by clamp 72 (Fig.9). The elastic membrane was placed between the outer rigid rim 9 and inner rim 10. Fig.9b shows the elastic membrane 18 after the membrane was thinned about 25% by stretching the elastic membrane 18 with the clamp 72. Fig. 9c shows the vacuum lid 7 with the thinned elastic membrane sandwiched between the inner and outer rims 9 an 10. The inner rim 10 is

U

prevented from separating from the outer rim 9 by the annular channel U in the outer rim 9 and the ridge 8 on the inner rim 10, where the thickness of the ridge 8 plus two times of the thickness of the thinned elastic membrane is larger than the gap for annular channel 11. To prevent the vacuum loss in the dish 2 when stored in refrigerator or freezer, the thinning of the elastic membrane 18 in the vacuum lid should be about 3% or more depending on the nature and original thickness of the elastic membrane, and be preferably more than 8% prior to affixing the membrane to the rigid rim 24.

It was found that after the Hd 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 Ud 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 mat 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.