Abstract:
A vacuum sealing method and system for evacuating air from and sealing a flexible plastic bag of the type having a mating male rib and a female sealing channel closure along the length of the bag opening. A flowable liquid is applied to the female channel. The rib and channel are engaged along their length to leave a short portion of the closure unclosed, a hollow tubular evacuation tube connected with a vacuum pump is inserted into the bag through the unclosed portion, pinching pressure is manually applied to sandwich the evacuation tube between the unclosed portion to prevent air from escaping, the vacuum pump is operated to withdraw a substantial amount of air from the bag, and thereafter the evacuation tube is quickly pulled from the bag so that the pinching pressure is transferred to the closure thereby closing the unclosed portion and sealing the evacuated bag with the liquid filling voids between the mating elements and providing a supplemental seal to increase resistance to air entering the sealed bag.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to flexible bag sealing apparatus and methods for vacuum sealing flexible plastic bags, and more particularly to a sealing system and method for vacuum sealing conventional plastic bags of the type having a mating male rib or bead and female sealing channel along the length of the bag opening. 
   2. Background Art 
   Closable plastic bags, particularly food storage bags, such as those commercially known as ZIPLOC® or GLAD-LOCK® bags, are widely used to preserve food. Such bags, also known as “zipper bags” or “profile bags”, typically have a mating male rib or bead and female channel extending along the opening of the bag that form an airtight closure when properly aligned and pressed together along the length of the bag opening. Naito, U.S. Pat. RE 28,969 discloses an example of an airtight profile closure is that used in the ZIPLOC® storage bag. The airtight closure it typically formed as an integral part of the bag and allows products stored in the bag to be easily removed and re-stored. 
   The freshness and quality of the product stored within the bag is to a large measure dependent upon the bag being substantially free of air. Thus, to preserve the contents of the bag in a fresh state, without loss of flavor and texture, it is desirable to evacuate or vacuum seal the bag. In sealing such profile closure bags, the user will usually attempt to manually squeeze the air from the bag while simultaneously trying to seal the opening. Unfortunately, the volume of air removed is generally inadequate, and air can still re-enter and become trapped in the bag upon initial sealing or re-sealing. 
   Others have attempted to overcome problems associated with manually sealing such profile closures by modifying the closure, providing specially designed bags, or providing bag attachments for evacuating the bag. 
   Kugler, U.S. Pat. No. 3,339,606 discloses a tongue and grove profile closure wherein the tongue is of a thickness less than the width of the groove and a releasable pressure sensitive adhesive is provided to keep the tongue within the groove. Adhesives, however, are difficult to apply, and may cause undesirable problems by sticking to other bags or miscellaneous surfaces. 
   Goto et al, U.S. Pat. No. 5,701,996 discloses a specially designed snap-fastener bag having a deaerating passage along a bottom-seal and a conventional snap fastener provided along the bag opening. The deaerating passage has an opening through one side of the bag and a sticky substance, such as polybutene, is disposed in the passageway to adhere the top and bottom plies of the plastic film of the bag after manually deaerating the bag. 
   Cox, U.S. Pat. No. 5,544,752, and Lambert, U.S. Pat. No. 6,085,906 disclose specially constructed evacuable storage bags having an integrally formed flexible conduit directed through the bag and into fluid communication with the interior of the bag and sealing strips positioned within or on the exterior of the conduit wherein pressure applied to an exterior of the conduit will effect collapsing thereof and cooperative engagement of the conduit sealing strips to preclude fluid communication through the conduit. 
   Kaufman, U.S. Pat. No. 4,018,253 discloses a vacuum device for freezer bags which includes a hollow retainer member adapted to receive the open end of the bag, and a cap member which is adapted to fit over the outside surface of the retainer in airtight engagement therewith. A flexible tube extends downwardly through the bottom end of the cap member and upwardly above the cap member, and a valve is provided on the upward part of the tube. The open end of the bag is inserted through the hollow retainer and draped over the top end of the retainer, and the cap is mounted over the top surface of the retainer and the open end of the bag in airtight engagement therewith so that the tube passage is in airtight communication with the interior of the bag. Air is withdrawn from the container through the tube, and the valve on the tube is then closed to close the tube passage. 
   Others have attempted to overcome problems associated with manually sealing bags having conventional profile closures by providing nozzle attachments that are to be connected with a household vacuum cleaner hose for evacuating the bag, which require additional time and trouble to relocate the vacuum cleaner. 
   Brown, U.S. Pat. No. 6,763,857 discloses a vacuum attachment for use with a vacuum hose and a vacuum device, and a conventional plastic food storage bag. The vacuum attachment has a first hollow substantially frustoconical attachment member for attaching the vacuum attachment to the vacuum hose, and a generally cylindrical inserter member for inserting the vacuum attachment into the bag. The vacuum attachment may also have an air flow blocker for blocking the air flow between the bag and the vacuum attachment. The air flow blocker is a hollow substantially cylindrical cap with a closed end, and may be provided with an opening or a filter. 
   Smith, U.S. Pat. No. 5,873,217 discloses a vacuum sealing method and nozzle adaptor apparatus for sealing a container such as a zipper-type plastic bag. The nozzle adapter has an elongated nozzle end for insertion into the container or bag and a larger vacuum hose-engaging end for engaging the hose of an existing vacuum source such as household vacuum cleaner. The elongate end of the nozzle is placed in the bag, the bag is sealed as completely as possible around the nozzle, the vacuum source is turned on. After the air is withdrawn from the bag, the nozzle is quickly removed from the bag and the open portion of the zipper-type seal is quickly engaged before a substantial amount of air can return into the bag. 
   Lau, U.S. Pat. No. 5,287,680 overcomes the problems associated with vacuum cleaner nozzle attachments by providing a hand-held battery operated vacuum packing device for evacuating and sealing a conventional plastic bag. The device has a housing with a pair of jaw elements mounted on a lever with a slot therebetween through which the edges of the bag are pulled to press fit the edges together. A nozzle extends outwardly from the housing and an air extractor fan in the housing withdraws air from the bag immediately before sealing is complete. With the jaws in an open position, the two mating edges of the bag are threaded together into the slot between the two jaw elements and the nozzle is placed in the bag. The lever is then operated to close the jaws. The bag and the vacuum packing device are then pulled in opposite directions, so that the two edges of the bag are pulled past the nozzle and through the slot into sealing engagement with one another. When the bag is sealed along almost the entire length of the edges, the extractor fan is operated to extract air from the bag through the nozzle. The lever is then released to open the jaws and the nozzle is withdrawn, and the sealing of the bag is completed manually. 
   A variety of specially designed large storage bags having air valve arrangements are also known in the art, such as disclosed in Yeager, U.S. Pat. No. 5,829,884 and Koyanagi, U.S. Pat. No. 6,499,600 have been proposed for the purpose of removing air from the storage bags in order to reduce the volume of an item, such as clothing, inside the bag to facilitate storage. 
   A variety of combination vacuum and heat sealing devices that include an electrical heat sealing unit combined with a vacuum pump are known in the art. Most of these types of heat sealing devices are not particularly suited for use with conventional profile closure bags and require special plastic bags, and some may cause burns and/or fumes, which may be potentially harmful. 
   Consequently, a need exists for a vacuum sealing system that will allow the user to vacuum pack the contents of a resealable flexible plastic bag that overcomes the foregoing drawbacks. 
   The present invention is distinguished over the prior art in general, and these patents in particular by a vacuum sealing method and system for evacuating air from and sealing a flexible plastic bag of the type having a mating male rib and a female sealing channel closure along the length of the bag opening, wherein a flowable liquid is applied to the female channel, the rib and channel are engaged along their length to leave a short portion of the closure unclosed, a hollow tubular evacuation tube connected with a vacuum pump is inserted into the bag through the unclosed portion, pinching pressure is manually applied to sandwich the evacuation tube between the unclosed portion to prevent air from escaping, the vacuum pump is operated to withdraw a substantial amount of air from the bag, and thereafter the evacuation tube is quickly pulled from the bag so that the pinching pressure is transferred to the closure thereby closing the unclosed portion and sealing the evacuated bag with the liquid filling voids between the mating elements and providing a supplemental seal to increase resistance to air entering the sealed bag. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the present invention to provide a vacuum sealing system and method for sealing conventional plastic bags of the type having a mating male rib or bead and female sealing channel along the length of the bag opening. 
   It is another object of this invention is to provide a vacuum sealing system and method for sealing conventional profile closure plastic bags wherein a liquid is applied to the female sealing channel of the bag to significantly reduce air leakage and facilitate a long lasting sealed condition. 
   Another object of this invention to provide a vacuum sealing system and method for sealing conventional profile closure plastic bags that is simple in operation and particularly suited for home use to allow a user to quickly and easily evacuate air from the bag and seal the bag to preserve the contents in a fresh state, without loss of flavor and texture. 
   Another object of this invention is to provide a liquid supplemented mating male rib or bead and female sealing channel type closure for conventional profile closure plastic bags wherein liquid is applied to the female sealing channel of the bag to significantly reduce air leakage and facilitate a long lasting sealed condition. 
   Another object of this invention is to provide a self contained vacuum sealing system for evacuating air from conventional profile closure plastic bags that does not require connection to a separate vacuum source. 
   A further object of this invention is to provide a vacuum sealing system and method for evacuating air from a flexible plastic bag that does not require customized storage bags having integrally formed air valves or conduit arrangements directed through the bag sealing strips. 
   A still further object of this invention is to provide a vacuum sealing apparatus for sealing conventional plastic bags that is simple in construction, inexpensive to manufacture and rugged and reliable in operation. 
   Other objects of the invention will become apparent from time to time throughout the specification and claims as hereinafter related. 
   The above noted objects and other objects of the invention are accomplished by the present vacuum sealing method and system for evacuating air from and sealing a flexible plastic bag of the type having a mating male rib and a female sealing channel closure along the length of the bag opening, wherein a flowable liquid is applied to the female channel, the rib and channel are engaged along their length to leave a short portion of the closure unclosed, a hollow tubular evacuation tube connected with a vacuum pump is inserted into the bag through the unclosed portion, pinching pressure is manually applied to sandwich the evacuation tube between the unclosed portion to prevent air from escaping, the vacuum pump is operated to withdraw a substantial amount of air from the bag, and thereafter the evacuation tube is quickly pulled from the bag so that the pinching pressure is transferred to the closure thereby closing the unclosed portion and sealing the evacuated bag with the liquid filling voids between the mating elements and providing a supplemental seal to increase resistance to air entering the sealed bag. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of the vacuum pump and evacuation tube apparatus of the vacuum sealing system for sealing a flexible plastic bag of the type having a mating male rib and a female sealing channel closure. 
       FIG. 2  is an elevation view of the evacuation tube of the vacuum sealing system, shown in partial cross section. 
       FIG. 3  is longitudinal cross section taken along line  3 - 3  of the lower end of the evacuation tube. 
       FIG. 4  is a top plan view taken along line  4 - 4  of a spider member of the evacuation tube. 
       FIG. 5  is an elevation view of the liquid applicator pen, with the lower portion shown in cross section. 
       FIGS. 6A and 6B  are enlarged transverse cross sectional views of a mating male rib or bead and female channel of a flexible plastic bag, respectively. 
       FIGS. 7-9  are pictorial views illustrating the steps in evacuating and sealing the flexible bag. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings by numerals of reference, there is shown in  FIG. 1 , a preferred vacuum sealing system  10  that allows a user to vacuum pack the contents of a resealable flexible plastic bag of the type having a mating male rib or bead and female sealing channel closure along the length of the bag opening. As used herein the term vacuum refers to an environment containing little or no air. 
   The vacuum sealing system  10  includes a vacuum pump apparatus  11  having a housing  12  which contains a conventional electrically driven vacuum pump P which may be, for example, a diaphragm pump or other type of miniature pump driven by an electric motor connectable with an electrical power source through an on-off switch  13  and an indicator light  14  such as a light emitting diode. The power source may be either 120v AC household voltage (in which case a transformer is disposed between the pump and the source), or it may be powered by disposable or rechargeable DC batteries. The pump, electrical circuitry and wiring details are conventional and well known in the art and therefore not shown or described in detail. A length of small diameter flexible hose or tubing  15  is connected at a first end to the suction side of the pump P and an evacuation tube  16  is connected to the opposed or second end of the hose or tubing. 
   As best seen in  FIGS. 2 ,  3  and  4 , the evacuation tube  16  has a hollow tubular upper portion  17  and a rigid elongate tubular lower portion  18  that is smaller in cross section than the upper portion. The lower end of the side wall of the elongate tubular lower portion  18  of the evacuation tube is provided with one or more longitudinal slots  18 A that extend upwardly a short distance from its bottom end. It should be understood that the side wall of the elongate tubular lower portion  18  of the evacuation tube  16  may be of a tubular or circular cross section, or may be of a polygonal cross section. Preferably, the tubular lower portion  18  is approximately 6 to 8 inches in length, and about ⅛ of an inch or less in diameter or major transverse dimension. 
   The upper portion  17  of the evacuation tube  16  is provided with external threads  17 A at its upper end and a radial flange  17 B beneath the threads. The interior of the upper portion  17  may be provided with spider member  19  disposed near its juncture with the smaller tubular lower portion  18 , which has a plurality of openings or air passageways  19 A formed therethrough. A small replaceable filter  20  formed of porous cellular material, such as polyurethane foam, is received in the interior of the upper portion and removably supported on the spider  19 . 
   A removable cap  21  having an internally threaded lower portion  21 A and a smaller diameter upper portion  21 B is threadedly and removably engaged on the external threads  17 A at the upper end of the evacuation tube  16 , and its smaller diameter upper portion  21 B is received and frictionally engaged in the second end of the hose or tubing  15 . 
   In a preferred embodiment, the present vacuum sealing system  10  also includes a liquid applicator  22  that contains a low-viscosity liquid, such a vegetable oil, which is used to apply a small quantity of the liquid onto the male/female fastener elements of the plastic bag, as described hereinafter. The applicator has a body  22 A with a protruding porous applicator tip  22 B and an end cap  23 , which is sized to fit onto the lower end of the body and enclose the protruding applicator tip when not in use. 
     FIG. 5  shows the internal construction of the liquid applicator  22  in detail. The liquid contained therein is not shown to avoid confusion. The body  22 A has a hollow generally cylindrical main portion  22 C defining an interior liquid reservoir chamber  22 D, which is enclosed at one end and has an opposed conical end  22 E adjoining a smaller diameter tubular portion  22 F with an opening  22 G extending therethrough. The conical portion  22 E between the main body portion  22 C and the smaller diameter tubular portion  22 F defines a conical interior valve seat  22 H. 
   A small valve member  23  having a conical upper portion  23 A received on the conical valve seat  22 H and a small diameter cylindrical lower end  23 B extending through the opening  22 G of the smaller diameter tubular portion  22 F is slidably mounted in the lower end of the applicator body  22 . The porous applicator tip  22 B is formed of porous cellular material, such as polyurethane foam, and is secured in a small bore in the outer end of the valve member  23 . A compression spring  24  has one end engaged on the conical upper portion  23 A of the valve member  23  and its opposed end is engaged on a spring retainer ring  25  disposed in the lower end of the main body  22 C. The outer diameter of the conical upper portion  23 A of the valve member  23  is smaller than the interior diameter of the reservoir chamber  22 D. The spring  24  urges the conical upper portion  23 A of the valve member  23  into fluid sealing engagement with the conical valve seat  22 H in a normally closed position to prevent liquid from exiting the reservoir chamber  22 D. 
   When the applicator tip  22 B is pressed against a surface, the conical portion  23 A of the valve member  23  is raised off of the valve seat  22 H to an open position allowing liquid (not shown) contained in the reservoir chamber  22 D to flow around the conical upper portion and small diameter cylindrical lower end  23 B of the valve member and is become absorbed into the porous cellular material of the applicator tip  22 B. 
   It should be understood that, depending upon the viscosity of the liquid used, the liquid applicator  22  may also be constructed in the manner of a conventional felt-tip pen, wherein the applicator tip is formed of felt or other fibrous material and is permanently mounted in the end of the main body and in fluid communication with the liquid contents, and the liquid is drawn by capillary action into the fibrous material to saturate the applicator tip. Alternatively, the liquid may also be maintained in a saturated fibrous cartridge disposed in the reservoir chamber  22 D which is in fluid communication with the applicator tip, whereby the liquid is drawn by capillary action from the fibrous material cartridge into the applicator tip. 
   Again, depending upon the depending upon the viscosity of the liquid used, the liquid applicator may also be provided as a small plastic squeeze container  26  ( FIG. 1 ) having a nozzle  26 A with a small orifice for dispensing a drop of the liquid when inverted or squeezed, such as an eye drop or nasal spray container. 
   In sealing food storage bags, the liquid contained in the applicator reservoir  22 D is a low-viscosity liquid, such as vegetable oil, olive oil, or cooking oil having a viscosity generally similar to that of water. When sealing bags that contain other non-edible products, other low-viscosity liquids, such as mineral oil or machine oil may be used. 
   The present vacuum sealing system is particularly suited for evacuating the air from within a conventional resealable flexible plastic bag of the type having a mating male rib or bead and female sealing channel closure along the length of the bag opening.  FIGS. 6A and 6B  show a typical conventional male  27  and female  28  sealing channel closure C in enlarged detail. For purposes of illustration, the conventional rib and groove is shown as an arrowhead shaped rib  27 A that is received by the locking jaws  28 B of a coacting female groove  28 A, but it will be understood and appreciated by those versed in the art that certain principles of the invention may apply equally to other modified forms of zipper closures and the reference to the rib and groove is not limiting except to the extent which the principles apply primarily to a rib and groove relationship. It should be understood that the present invention is not to be limited to the specific form of rib and groove illustrated in the drawings. 
   OPERATION 
   Referring now additionally to  FIGS. 7 ,  8  and  9 , in a liquid supplemented sealing method, the liquid applicator  22  is used to apply a small amount of the liquid L contained therein to the female channel  28 A of the bag closure. This is accomplished by opening the sealing channel closure of the bag B, placing the porous tip  22 B of the applicator  22  at one end of the female channel  28 A and sliding it along the channel to the opposite end ( FIG. 7 ), or by applying a drop of the liquid into the female channel. The liquid L then runs into the channel  28 A and becomes generally evenly distributed therein along its length ( FIG. 6A ). The item or items to be stored may be inserted into the body of the bag before or after application of the liquid into the female channel. 
   The user then partially closes the bag B by pinching the mating male rib or bead  27 A and female channel  28 A together and running their thumb and forefinger along the length of the closure, but leaving a short length unclosed of sufficient size to receive the elongate tubular lower portion of the evacuation tube ( FIG. 8 ), and then inserts the tubular lower portion  18  of the evacuation tube  16  into the bag through the small opening formed by the unclosed portion of the seal ( FIG. 9 ). 
   After the elongate tubular lower portion  18  of the evacuation tube  16  has been inserted, the user, with their thumb and forefinger, tightly pinches the unclosed portion of the rib or bead  17 A and channel  28 A closely around the lower portion of the evacuation tube sandwiched therebetween to prevent air from escaping ( FIG. 9 ). 
   While holding the pinching pressure on the rib or bead  27 A and channel  28 A and sandwiched lower portion  18  of the evacuation tube  16 , the user turns the on-off switch to the “on” position to activate the pump apparatus. The elongate slots  18 A on the lower end of the side wall of the tubular lower portion  18  of the evacuation tube  16  substantially prevent the interior surface of the bag from being sucked in and plugging the bore at the end of the tube. The evacuation tube  16  may also be manually rotated about its axis in the event that the interior surface of the bag does get drawn into the bore or slots, to open the evacuation passageway. 
   After the desired amount of air has been evacuated, and while maintaining the pinching pressure, the lower portion  18  of the evacuation tube  16  is quickly pulled from the bag, and the pinching pressure is automatically transferred to engage and pinch closed the previously unclosed portion of the rib or bead  17 A and channel  28 A, and thereby sealing the evacuated bag. 
   As shown in  FIG. 6B , when the mating male rib or bead  27 A and female channel  18 A closure is closed, the liquid L in the channel will occupy any voids between the surfaces of the engaged mating elements and serve as a supplemental seal to prevent air from entering, and maintain the seal for a significantly longer period than would be maintained by the engaged mating elements in a dry condition. 
   However, it should be understood that the vacuum sealing method may also be carried out without first applying the liquid into the female channel of the bag closure to achieve an effective vacuum seal. 
   The liquid supplemented sealing method may also be carried out to achieve a superior long-lasting air leakage resistant seal by manually venting air from the bag rather than utilizing the pump. In this method, the liquid applicator  22  is used to apply a small amount of the liquid contained therein to the female channel  28 A of the bag closure, as described above. The liquid then runs into the channel and becomes generally evenly distributed therein along its length. The item or items to be stored may be inserted into the body of the bag before or after application of the liquid into the female channel. 
   The user then manually squeezes air from the bag and, while pinching the mating male rib or bead and female channel together, runs their thumb and forefinger along the length of the opening, in a conventional manner, to engage and close the rib or bead and channel, and thereby sealing the evacuated bag. When the mating male rib or bead and female channel closure is closed, the liquid in the channel will occupy any voids between the surfaces of the engaged mating elements and serve as a supplemental seal to prevent air from entering, and maintain the seal for a significantly longer period than would be maintained by the engaged mating elements in a dry condition. 
   While this invention has been described fully and completely with special emphasis upon preferred embodiments, it should be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.