Airtight lid for container and method of use

Abstract

A lid for forming an airtight seal to a bowl or dish plate to elongate the life of product therein comprises an impermeable membrane having an outer perimeter larger than the rim of the container and an enforcement ring for enabling the formation of an airtight seal between the membrane and rim of the container under vacuum. The membrane is sufficiently soft to cause it to fill the lower sections or imperfections on the rim, thus enabling the lid to form an airtight seal to almost all household containers. The membrane may be adapted to have sufficient low tensile stress, thereby preventing the vacuum in the container from imploding or collapsing the container even if it has a thin or weak wall. The enforcement ring has vertical and horizontal rings connected to the membrane perimeter to prevent the membrane deformation at both vertical and horizontal directions. The lid may further comprise an air evacuation passageway having an air collection chamber for extracting air from the container and a valve for allowing air to flow out of the container but preventing air from entering. In use, the lid may be sealed to a container by simply pushing the membrane into the container and releasing the membrane to generate a vacuum to affix the membrane to the container, or may be sealed to a container by connecting a vacuum generator to the evacuation passageway to evacuate the container.

1 . A lid for sealing a container having an opening for allowing a product to be placed into the container, a side wall and a rim at the free end of the side wall under a subatmospheric pressure or vacuum to increase the life of the product, said lid comprising a substantially impermeable membrane having an outer perimeter at least as large as the rim of the container to cover the container and an enforcement means for preventing said outer perimeter from substantial deformation when said membrane is being elongated, said membrane being adapted to enter the container to contact at least part of the side wall of the container as well as to wrap around at least the top end of the product therein when a subatmospheric pressure or vacuum is formed in the space between said membrane and the container, thereby causing said membrane to conform substantially to the topographies of the side wall of the container and the product to prevent the container from being imploded or collapsed by said vacuum or subatmospheric pressure.  
   
   
       2 . A lid as defined in  claim 1  wherein said impermeable membrane is adapted to be sufficiently expandable or stretchable to prevent breakage or puncture by the product, and adapted to have a tensile stress lower than 2R p /L pounds per square inch at a tensile strain of approximately 20% to 50% elongation to prevent said membrane from crushing or damaging the product under said subatmospheric pressure, wherein R p  and L are the radius or equivalent radius of the product and the membrane thickness in inches, respectively.  
   
   
       3 . A lid as defined in  claim 1  wherein said impermeable membrane is adapted to be sufficiently expandable or stretchable to prevent breakage or puncture by the product, and adapted to have a tensile stress lower than 2R m /L pounds per square inch at a tensile strain of approximately 20% to 50% elongation to prevent said membrane from substantially deforming the container that has a thin or weak wall under said vacuum or subatmospheric pressure, wherein R m  and L are the radius or equivalent radius and thickness of said membrane in inches, respectively, thereby saving the amount of materials used to construct the container.  
   
   
       4 . A lid as defined in  claim 1  wherein said impermeable membrane is adapted to retain at least a substantial part of its barrier to air after being expanded or stretched into the container, and adapted to have a tensile stress sufficiently low to reduce the rate of air diffusion through said membrane into the container under said subatmospheric pressure.  
   
   
       5 . A lid as defined in  claim 4  wherein said tensile stress is adapted to be lower than 5R m /L pounds per square inch at a tensile strain of approximately 20% to 50% elongation, wherein R m  and L are the radius or equivalent radius and thickness of said membrane in inches, respectively.  
   
   
       6 . A lid as defined in  claim 1  wherein said enforcement means comprises an enforcement ring permanently connected to said outer perimeter or to a region near said outer perimeter on said impermeable membrane, said enforcement ring being adapted to prevent any wrinkles from forming on the section of said membrane located above the rim or side wall of the container as said membrane is pulled down to conform substantially to the topographies of the side wall of the container and the product by the subatmospheric pressure or vacuum.  
   
   
       7 . A method for using the lid of  claim 6  comprising placing a product into the container, placing said lid on the container in such a way that said enforcement ring is outside the rim of the container, removing air in the space between said membrane and the container to create a vacuum or subatmospheric pressure therein, and allowing the air or gas pressure above said membrane to cause said membrane to elongate and conform to the topographies of the side wall of the container and the product.  
   
   
       8 . A lid as defined in  claim 1  wherein said enforcement means comprises a first fusible material on said impermeable membrane and a second fusible material on the rim of the container adapted to fuse to said first fusible material on the perimeter area of said impermeable membrane, thereby enabling the rim of the container to prevent said outer perimeter of said impermeable membrane from being substantially deformed as said membrane is pulled down to conform substantially to the topographies of the side wall of the container and the product by the subatmospheric pressure or vacuum.  
   
   
       9 . A method for using the lid of  claim 8  comprising placing a product into the container, placing said lid on the rim of the container, enclosing the container with said membrane thereon in a vacuum chamber to remove air in the space between said membrane and the container to create a vacuum or subatmospheric pressure therein, fusing said first material on the perimeter area of said membrane to the second material on the rim of the container in the vacuum chamber, and allowing air or gas to enter the vacuum chamber, the air or gas pressure causing said membrane to elongate and conform to the topographies of the side wall of the container and the product.  
   
   
       10 . A lid for forming an airtight seal to a container having an open end for receiving a product into the container, a side wall and a rim at the free end of the side wall, said lid comprising an air impermeable membrane having an outer perimeter at least as large as the rim of the container and an enforcement ring permanently connected to said outer perimeter or to an area near said outer perimeter on said membrane for facilitating the formation of an airtight seal between said membrane and the rim of the container, said membrane being sufficiently flexible and adapted to enable the part of said membrane that is in contact with the rim or side wall of the container to conform to the topography of the rim or side wall to prevent any air passageway from being formed between said membrane and the rim or side wall of the container.  
   
   
       11 . A lid as defined in  claim 10  wherein said membrane is adapted to be stretched at least partially into the container by hand or force to drive air out of the container, said membrane being further adapted to have a tendency to return to its original shape to generate a subatmospheric pressure or vacuum in the container, thereby affixing said membrane to the rim of the container at least in part by said subatmospheric pressure.  
   
   
       12 . A lid as defined in  claim 10  wherein said air-impermeable membrane is adapted to sink into the container to contact the side wall of the container when a subatmospheric pressure or vacuum is formed in the space between said membrane and the container, thereby reducing the risk of implosion or collapse of the container by said subatmospheric pressure or vacuum.  
   
   
       13 . A lid as defined in  claim 12  wherein said impermeable membrane is sufficiently thin to enable said membrane to wrap around at least the top end of the product in the container when the subatmospheric pressure or vacuum is formed in the space between said membrane and the container.  
   
   
       14 . A lid as defined in  claim 10  wherein said air impermeable membrane is an elastic or rubbery membrane adapted to be stretched by a subatmospheric pressure in the container and to return substantially to its original shape after removal of said subatmospheric pressure.  
   
   
       15 . A lid as defined in  claim 10  wherein said membrane comprises a bulge adapted to accommodate at least a part of the product in the container to enable an intimate contact between the peripheral area of said membrane and the rim of the container in case that the product protrudes out of the container or that the container has too short a side wall or no side wall.  
   
   
       16 . A lid as defined in  claim 10  wherein said enforcement ring is adapted to have sufficient resistance to both horizontal and vertical deformation when said membrane is being pushed down by hand or force or pulled down by a partial vacuum into the container, thereby preventing the formation of wrinkles on said membrane and air channels between said membrane and the rim or side wall of the container.  
   
   
       17 . A lid as defined in  claim 16  wherein said enforcement ring comprises a first ring and a second ring permanently connected to said first ring at an angle smaller than 180 degrees.  
   
   
       18 . A lid as defined in  claim 16  wherein said enforcement ring further has a third ring connected to said second ring to clamp the peripheral section of said membrane between said first and third rings.  
   
   
       19 . A lid as defined in  claim 16  wherein said enforcement ring adopts one of a substantially circular shape, a substantially oval shape, and a substantially rectangle or square shape with rounded corners to help preventing said horizontal deformation when said membrane is being pushed or pulled into the container.  
   
   
       20 . A lid as defined in  claim 10  wherein said membrane is made from a rubber or elastomer material selected from the group consisting of butyl rubber and ethylene acrylic elastomer, thereby providing said membrane sufficient barrier to air when said membrane is at its elongated or stretched state.  
   
   
       21 . A lid as defined in  claim 10  wherein said air-impermeable membrane comprises a polymeric barrier layer adapted to retain at least some of its barrier to air after said membrane is pushed by force or pulled by a subatmospheric pressure or vacuum into the container.  
   
   
       22 . A lid as defined in  claim 21  wherein said membrane comprises an elastomer layer selected from the group consisting of natural rubber, synthetic rubber and thermoplastic eleatomer.  
   
   
       23 . A lid as defined in  claim 22  wherein said elastomer layer is at least twice as thick as said polymeric barrier layer, thereby allowing said membrane to return substantially to its original shape when the pressure below said membrane reaches atmospheric pressure.  
   
   
       24 . A lid as defined in  claim 10  wherein said air impermeable membrane comprises a material adapted to fuse to said enforcement ring when heated by heat, vibration or light energy.  
   
   
       25 . A lid as defined in  claim 10  further comprising a handle having a first end attached to said membrane and a second end adapted for a user to pull to create an air passageway between said membrane and the container to allow air to enter the container, thereby facilitating the removal of said lid from the container.  
   
   
       26 . A lid as defined in  claim 10  further comprising a film strip attached to said membrane in such a way that an air passageway is created between said membrane and the container by pulling up on an unsecured end portion of said film strip, thereby allowing air to enter the container to facilitate the removal of said lid.  
   
   
       27 . A lid as defined in  claim 10  wherein said membrane further comprises an opening to allow hot gaseous fluid from a generator to be introduced to the product in the closed space between said membrane and the container, thereby causing the product to be heated or cooked.  
   
   
       28 . A lid as defined in  claim 10  further comprising an inlet connected or adapted to connect to a generator to introduce hot gaseous fluid from the generator to the product in the closed space between said membrane and the container, thereby causing the product to be heated or cooked.  
   
   
       29 . A lid as defined in  claim 10  further comprising a plate above said membrane and connected to said enforcement ring and an air space between said plate and said membrane.  
   
   
       30 . A lid as defined in  claim 10  further comprising an inlet for receiving hot gaseous fluid from a generator, said lid being adapted to form a gap between said membrane and container to release some hot gaseous fluid when the pressure below said membrane reaches a predetermined value.  
   
   
       31 . A lid as defined in  claim 10  further comprising an inlet for introducing hot gaseous fluid from a generator into the container and an outlet for returning at least part of the hot gaseous fluid to the generator, thereby causing circulation of the hot gaseous fluid between the generator and the closed space defined by said membrane and the container to heat or cook the product.  
   
   
       32 . A lid as defined in  claim 31  further comprising said generator having a heater for evaporating the water from a reservoir to produce hot steam and an gas pump for circulating hot gaseous fluid comprising hot steam in a loop comprising said heater, said inlet, said closed space, said outlet and said gas pump.  
   
   
       33 . A lid as defined in  claim 32  wherein said generator further comprises a liquid pump for delivering water to said heater and a metering device for controlling the amount of water delivered to said heater.  
   
   
       34 . A lid as defined in  claim 33  wherein said metering device comprises a humidity meter for measuring the humidity of the hot gaseous fluid and providing an electric signal to said liquid pump or a valve to stop the delivery of water to said heater when the humidity is above a predetermined value and to start delivery of water to said heater when the humidity is below a predetermined value.  
   
   
       35 . A lid as defined in  claim 32  wherein said gas pump comprises a blade for converting the water from the reservoir into microscopic droplets or mist and delivering the droplets or mist to said heater.  
   
   
       36 . A lid as defined in  claim 32  wherein said generator further comprises an air valve for controlling the amount of air available to said gas pump, thereby controlling the percent of hot air in the hot gaseous fluid.  
   
   
       37 . A lid as defined in  claim 31  further comprising said generator having a heater for heating air to produce hot air and an gas pump for circulating the hot gaseous fluid comprising hot air in a loop comprising said heater, said inlet, said closed space, said outlet and said gas pump.  
   
   
       38 . A lid as defined in  claim 31  further comprising said generator having a heater for producing hot gaseous fluid and a gas pump for circulating hot gaseous fluid in a loop comprising said heater, said inlet, said closed space, said outlet and said gas pump, said generator being adapted to deliver ambient air to the container via said inlet to cool said membrane and the container after finishing heating or cooking the product.  
   
   
       39 . A lid as defined in  claim 10  further comprising a thin layer of fluid on said membrane to prevent or retard air from entering the container, said fluid being one of a liquid, paste and gel.  
   
   
       40 . A lid as defined in  claim 10  wherein said air impermeable membrane further comprises a tacky or adhesive material to cause said membrane to reversibly adhere to the container to prevent or retard air from entering the container.  
   
   
       41 . A lid as defined in  claim 10  wherein said air impermeable membrane is substantially transparent to light to make the product in the container visible, and said membrane further comprises an effective amount of an antifogging additive to ensure clear visibility of the product through said membrane.  
   
   
       42 . A lid as defined in  claim 10  wherein said impermeable membrane is adapted to be sufficiently expandable and to have a tensile stress sufficiently low to retard air from entering the container under a subatmospheric pressure or vacuum.  
   
   
       43 . A lid as defined in  claim 10  wherein said air impermeable membrane is adapted to enable one to push said membrane into the container to drive air out of the container, said membrane being further adapted to generate a partial vacuum in the container by simply stopping pushing said membrane.  
   
   
       44 . A lid as defined in  claim 43  further comprising a push facilitator on or attached to said membrane for facilitating one to push said membrane into the container, said facilitator being substantially more rigid than said membrane.  
   
   
       45 . A lid as defined in  claim 10  wherein said impermeable membrane is adapted to be sufficiently expandable and to have a tensile stress lower than 3R m /L pounds per square inch at a tensile strain of approximately 20% to 50% elongation to enable said lid to be used seal a container having a relatively thin or weak wall under a subatmospheric pressure, wherein R m  and L are the radius or equivalent radius and thickness of said membrane in inches, respectively.  
   
   
       46 . A lid as defined in  claim 10  wherein said air impermeable membrane comprises a side wall section, at least part of which has a perimeter smaller than the rim of the container, and a substantially horizontal center section, at least said side wall section of said membrane being rubbery or elastic in order to form an airtight seal between the rim of the container and said side wall section.  
   
   
       47 . A lid as defined in  claim 46  wherein said substantially horizontal center section of said impermeable membrane is adapted to be pushed at least partially into the container by hand or force, said membrane being adapted to have a tendency to return to its original shape to cause a vacuum or subatmospheric pressure in the container to improve the sealing of said lid to the rim of the container.  
   
   
       48 . A lid as defined in  claim 46  wherein said enforcement ring is larger than at least part of said side wall section of said membrane to facilitating the mounting and sealing of said lid to the container.  
   
   
       49 . A lid as defined in  claim 46  wherein said enforcement ring is elastic.  
   
   
       50 . A lid as defined in  claim 46  wherein said side wall section is adapted to have a sufficiently low strength to reduce the force needed to stretch said side wall section to enlarge the diameter of said side wall section, thereby facilitating the mounting of said lid over the container.  
   
   
       51 . A lid as defined in  claim 46  further comprising a valve having a vent opening on said horizontal center section of said membrane and a seal member connected to said membrane for covering said vent opening, said seal member being adapted to open when one places said lid over the container and pulls said enforcement ring downward to allow the air enclosed between said membrane and the container to escape through said vent opening, thereby reducing the force needed to pull said enforcement ring downward to cause said side wall section of said membrane to form a sufficient seal to the rim of the container.  
   
   
       52 . A lid for forming an airtight seal to a container such as a bowl, dish plate, canister, cup, jar, tray or bottle that has an open end, a bottom, a side wall between the open end and bottom, and a rim at the open end, said lid comprising an air-impermeable membrane having an outer perimeter at least as large as the rim of the container to cover the open end of the container and an air evacuation passageway comprising a valve for allowing air to be evacuated from the container but preventing air from entering the container via said evacuation passageway, said membrane being sufficiently flexible to enable the part of said membrane above the rim or side wall of the container to conform to the topography of the rim or side wall to prevent air passageway from forming between said membrane and the rim or side wall of the container.  
   
   
       53 . A lid as defined in  claim 52  wherein said evacuation passageway further comprises a film having numerous microscopic openings adapted to allow air to exit the container but to prevent particulate or solid matters from passing through, thereby preventing the loss of product when the container is evacuated via said evacuation passageway.  
   
   
       54 . A lid as defined in  claim 53  wherein said film is sufficiently hydrophobic to become impermeable when liquid reaches said film, thereby preventing the loss of liquid in the product when the container is evacuated via said evacuation passageway.  
   
   
       55 . A lid as defined in  claim 52  wherein said impermeable membrane is adapted to be pushed at least partially into the container by hand or force to evacuate air out of the container via said evacuation passageway, said membrane being further adapted to have a tendency to return to its original shape to generate a subatmospheric pressure in the container, thereby causing said lid to seal to the container at least in part by said subatmospheric pressure.  
   
   
       56 . A lid as defined in  claim 55  further comprising a push facilitator attached to said membrane apart from said enforcement ring to avoid weakening the seal between said membrane and container.  
   
   
       57 . A lid as defined in  claim 52  further comprising an enforcement ring connected to said outer perimeter or to a region near said outer perimeter on said impermeable membrane for preventing substantial deformation of said outer perimeter of said membrane when said membrane is elongated by force or vacuum, thereby facilitating the formation of the airtight seal between said membrane and the container.  
   
   
       58 . A lid as defined in  claim 57  further comprising a support member positioned above said membrane and connected to said enforcement ring and an air space between said support member and said membrane to facilitate the formation of the airtight seal between said membrane and the container.  
   
   
       59 . A lid as defined in  claim 58  further comprising a rubber gasket in said air space, said rubber gasket is sufficiently thinner than an air space so that said impermeable membrane is apart from said rubber gasket to facilitate the formation of said airtight seal.  
   
   
       60 . A lid as defined in  claim 52  wherein said membrane is selected from the group consisting of a rubber or elastomer membrane and a composite membrane having an elastomer layer and at least one of a readily stretchable polymeric barrier layer and sealant skin layer.  
   
   
       61 . A lid as defined in  claim 52  wherein said valve comprises a seal member, a valve opening normally closed by said seal member, and an elongated member having one end connected to said seal member and a free end, said seal member being adapted to open said valve opening when air is evacuated from the container or when one pulls said free end of said elongated member, said elongated member being adapted to be sufficiently flexible to prevent unintended release of the vacuum in the container when said elongated member is accidentally touched by another container or object.  
   
   
       62 . A lid as defined in  claim 52  wherein said valve comprises a valve opening through said membrane, a seal member located below said membrane, a retainer located above said membrane and connected to said seal member by a stem, and a spring for pulling said seal member upwards to close the valve opening, said retainer, seal member and spring being configured to allow one to apply a sufficient force to said retainer to push said seal member down to open said valve opening and push said membrane into the container to drive air out of said valve opening and to remove said sufficient force to cause a subatmospheric pressure or vacuum in the container, and to allow one to apply to said retainer a smaller force large enough to push said seal member down to release said vacuum but small enough to allow said membrane to return to its original shape.  
   
   
       63 . A lid as defined in  claim 52  wherein said valve comprises a valve body, an valve opening, a seal chamber having a bottom wall adapted to close said valve opening and an upper wall with an opening, a knob rotationally connected to said valve body, a presser having a plunger slidingly received in said seal chamber and a stem slidingly received in said opening on said upper wall for connecting said plunger to said knob, said knob being adapted to move among a first position at which the seal chamber can freely move up and down to allow the removal of air from the container, a second position at which the plunger presses said bottom wall of said seal chamber against said valve opening and a third position at which the plunger lifts said seal chamber up to allow air to enter the container.  
   
   
       64 . A lid for sealing a container having an opening for allowing a product to be placed into the container, a side wall and a rim at the free end of the side wall under a subatmospheric pressure or vacuum to increase the life of the product, said lid comprising a thin body affixed on the side wall of the container to close the opening of the lid at least in part by the subatmospheric pressure or vacuum in the container and a valve having a seal member located above said thin body, a valve opening on said thin body and normally closed by said seal member, and a slender member having one end connected to said seal member and a free end, said seal member being adapted to open said valve opening when one pulls said free end of said slender member, said slender member being adapted to be sufficiently flexible to prevent unintended release of the vacuum in the container when said slender member is accidentally touched by another container or object.  
   
   
       65 . A lid as defined in  claim 64  further comprising a chamber for preventing said seal member from being accidentally touched by another container or object to cause unintended release of the vacuum in the container, said chamber having an opening for allowing said free end of said slender member to pass through.  
   
   
       66 . A lid as defined in  claim 64  further comprising a thin fluid layer including one of a high boiling point liquid layer, a gel and a paste layer on said seal member to facilitate the closure of said valve opening.  
   
   
       67 . A lid as defined in  claim 64  further comprising a retainer below said thin body and connected to said seal member by a stem in such a way that said thin body is between said seal member and said retainer, said retainer being adapted to apply an elastic tension to said seal member to cause said seal member to seal said valve opening even after the loss of vacuum in the container, said elastic tension being sufficiently small to allow the opening of said valve by pulling said free end of said slender member.  
   
   
       68 . A lid as defined in  claim 64  wherein said lid further comprises a film having numerous microscopic openings adapted to prevent particulate or solid matters from passing through said valve opening.  
   
   
       69 . A lid as defined in  claim 68  wherein said film is sufficiently hydrophobic to retain its permeability to air after the liquid in the product contacted said film, thereby enabling air to enter the container when said free end of said slender member is pulled.  
   
   
       70 . In a container having a top part and a bottom part sealed or adapted to seal to said top part to enclose a product under a subatmospheric pressure or vacuum to increase the life of the product, the improvement comprising a substantially air impermeable membrane for at least one of said top and bottom parts of the container, said air impermeable membrane comprising a material having sufficient barrier to air to maintain said subatmospheric pressure for an extended period of time and being capable of expanding or stretching at least 50% prior to causing any significantly deterioration of said sufficient barrier to air by said subatmospheric pressure or vacuum, thereby allowing said membrane to wrap around at least the part of the product, said membrane being configured to have a tensile stress lower than 2R p /L pounds per square inch at a tensile strain of approximately 20% to 50% elongation to prevent said membrane from crushing or damaging the product under said subatmospheric pressure, wherein R p  and L are the radius or equivalent radius of the product and the membrane thickness in inches, respectively.  
   
   
       71 . A lid as defined in  claim 70  wherein said tensile stress is adapted to be lower than 0.5R p /L pounds per square inch at a tensile strain of approximately 20% to 50% elongation to enable the product to be a crushable or delicate selected from the group consisting of fruit, vegetables, fried product, baked product, dried species and fragile items below said membrane when said vacuum or subatmospheric pressure is present.  
   
   
       72 . A lid as defined in  claim 70  wherein said membrane is a rubber or elastomer membrane.  
   
   
       73 . A lid as defined in  claim 70  wherein said membrane is a composite membrane having a rubber or elastomer layer and at least one of a readily stretchable polymer barrier layer and sealant layer.