VACUUM STORAGE BAG
A vacuum storage bag providing an interior volume for storing food items in an evacuated condition has air flexible sidewalls made of a gas permeable material. The gas permeable sidewalls can be made of multiple layers including a heat sealing innermost layer and a relatively stronger, outwardly disposed gas permeable layer. The heat sealing layer can be low density polyethylene to facilitate forming of the bag with heat seals and the stronger gas permeable layer can be high density polyethylene to provide the bag with sufficient strength and toughness. In various embodiments, the storage bag can include interlocking closure strips for releasably closing an opening, a one-way vacuum valve for evacuating the interior volume, and a textured portion along one sidewall to facilitate evacuation.
Flexible plastic bags are used for a variety of purposes including storing food items, either temporarily in the case of packaging snacks or long term as in the case of freezer storage. Plastic bags of this style are typically made from one or more sheets of flexible plastic material arranged to provide an interior volume that is accessible through an opening. To close the opening after insertion of food items, interlocking closure strips may be provided about the rim of the opening. Likewise, the plastic material comprising the rim may be heat sealed together or glued together with a pressure sensitive adhesive to more permanently seal the opening.
One common problem that occurs with such bags is that after the opening has been sealed, latent air may remain trapped in the interior volume. In addition to undesirably increasing the overall size of the bag, the trapped air can cause spoilation or dehydration of the stored food items. Further, in freezer storage applications, the trapped air can contribute to freezer burn of the stored food items.
BRIEF SUMMARY OF THE INVENTIONThe invention provides a vacuum storage bag made with flexible plastic sidewalls of an air permeable material or materials. To improve manufacturability of the bag and provide adequate toughness for use in vacuum applications, the sidewall materials can include multiple plies or layers of air permeable materials including a heat sealable innermost layer and a tougher and stronger, outwardly situated, gas permeable layer. An example of a material sufficient for the heat sealable inner layer includes low density polyethylene and an example of a material suitable for the stronger gas permeable layer includes high density polyethylene. Though such materials are not truly gas impermeable, they provide sufficient resistance to air penetration to adequately maintain a vacuum state acceptable for food storage.
When the two sidewalls of the storage bag are overlaid and arranged to provide an interior volume, the heat sealable inner layers of the sidewalls can be joined together by a heat sealing operation to form the closed edges of the bag. The stronger layer, which may not be as susceptible to forming heat seals, provides sufficient toughness to resist destructive deformation or stretching of the bag while under vacuum. For example, in absence of the stronger layer, stretching of the sidewalls about stored food items during evacuation may cause the bag to develop small holes or tears thereby compromising the vacuum.
An advantage of the inventive vacuum storage bag is that manufacture of the bag is facilitated by having heat sealable inner layers as part of the sidewall. Another advantage is that the stronger, outer layer provides sufficient toughness to preclude destructive deformation of the sidewalls and resist the ingress of air into the interior volume. Another advantage is that the invention provides a vacuum storage bag that can be made from relatively low cost, gas permeable materials. These and other features and advantages of the invention will be apparent from the foregoing drawings and detailed description of the embodiments.
Now referring to the drawings, wherein like reference numbers refer to like features, there is illustrated in
To releasably close the opening 116 after insertion of an item for storage, there can be attached to the first and second sidewalls 102, 104 and parallel to the open top edge respective first and second fastening strips 120, 122. The first and second fastening strips 120, 122 can be formed from extruded, flexible thermoplastic and extend between the first and second side edges 110, 112. As will be appreciated by those of skill in the art, the first and second fastening strips 120, 122 can engage to form a seal which closes the normally open top edge 116. Of course, in other embodiments or in combination with the interlocking strips, other methods such as the use of pressure sensitive or cold seal adhesives such as those disclosed in U.S. Pat. No. 6,149,304, herein incorporated by reference in its entirety, heat-sealing, or cling can be employed to seal the opening 116.
To evacuate air trapped in the interior volume 106 after sealing closed the opening 116, in the illustrated embodiment, a one-way valve element 130 is attached to the first sidewall 102 and communicates with the interior volume. The one-way valve element 130 is capable of opening to allow entrapped air to escape from the enclosed interior volume 106 and of closing to prevent the ingress of environmental air. Evacuation through the valve element 130 can be accomplished by squeezing the first and second sidewalls together or by using a vacuum source. As explained in more detail below, to promote evacuation through the one-way valve element, an inner surface of at least one sidewall can include a textured portion to provide air flow paths toward the valve element. While the valve element and the textured portion provide one manner of evacuating air from the interior volume, in other embodiments, other evacuation methods can be utilized that, for example, operate with and during the sealing of the opening.
In accordance with an aspect of the invention, to improve manufacturability and durability of the storage bag, the flexible sidewalls can be made from a gas permeable, multilayered material. More specifically, as illustrated in
Characteristically, low density polyethylene has a lower density, lower tensile strength and lower melt temperature but is more flexible and pliable than high density polyethylene. For example, low density polyethylene can have a density of between about 0.91 grams per cubic centimeter (g/cc) to about 0.94 g/cc, a melt temperature of about 120° C., and a tensile strength of about 7670 PSI in the machine direction and 6670 PSI in the cross-direction. High density polyethylene can have a density of between about 0.94 g/cc to about 0.96 g/cc, a melt temperature of about 135° C., and a tensile strength of about 11,999 PSI in the machine direction and 9600 PSI in cross-direction.
Referring to
In the embodiment illustrated in
In various embodiments, each sidewall can have an overall thickness 146 between the inner and outer surfaces as shown in
Referring to
Also shown in
Referring to
The one-way valve element attached to the storage bag can be any suitable one-way valve element. For example, referring to
Disposed concentrically into the valve body 210 is a counter-bore 228. The counter-bore 228 extends from the first flange face 220 part way towards the boss face 224. The counter-bore 228 defines a cylindrical bore wall 230. Because it extends only part way toward the boss face 224, the counter-bore 228 may form within the valve body 210 a planar valve seat 232. To establish fluid communication across the valve body 210, there is disposed through the valve seat 232 at least one aperture 234. In the illustrated embodiment, a plurality of apertures 234 are arranged concentrically and spaced inwardly from the cylindrical bore wall 230.
To cooperatively accommodate the movable disk 212, the disk is inserted into the counter-bore 228. Accordingly, the disk 212 may be smaller in diameter than the counter-bore 228 and has a thickness as measured between a first disk face 240 and a second disk face 242 that is substantially less than the length of the counter-bore 228 between the first flange face 220 and the valve seat 232. To retain the disk 212 within the counter-bore 228, there is formed proximate to the first flange face 220 a plurality of radially inward extending fingers 244. The disk 212 can be made from any suitable material such as, for example, a resilient elastomer.
Referring to
To attach the valve element 200 to the first sidewall, referring to
In other embodiments, the one-way valve element can have a different construction. For example, the one-way valve element can be constructed from flexible film materials.
Referring to
When a pressure differential is applied across the valve element by, for example, placing the nozzle of an evacuation device adjacent the first sidewall 302 about the valve element, the top layer 314 can be partially displaced from the base layer 312 thereby exposing the aperture 316. Air from the interior volume 306 can pass through the hole 308 and aperture 316 and along the channel formed between the adhesive strips 318 where the removed air enters the evacuation device. When the suction force generated by the evacuation device is removed, the resilient top layer 314 will return to its prior configuration covering and sealing the aperture 316. The valve element 310 may also contain a viscous material such as an oil, grease, or lubricant between the two layers in order to prevent air from reentering the bag. In another embodiment, the base layer 312 may also be a rigid sheet material.
Illustrated in
As mentioned above with reference to
The textured portion can be produced by any suitable method including, for example, embossing or coining the air permeable sheet material used to produce the bag sidewalls. Because embossing the sheet material may reduce the thickness of the sheet material in certain areas, it may be necessary to start with a thicker sheet and then manufacture or process the sidewalls to the desired finished thickness.
The vacuum source connected to the nozzle 506 in
In the embodiment illustrated in
Referring back to
Of course, in other embodiments, the textured portion need not be provided over substantially the entire inner surface. For example, in the embodiment illustrated in
All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.
The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,” ) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
Preferred embodiments of this invention are described herein, including the best mode known to the inventor(s) for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor(s) expect skilled artisans to employ such variations as appropriate, and the inventor(s) intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
Claims
1. A vacuum storage bag comprising:
- a first flexible, gas permeable sidewall; and
- a second flexible sidewall overlaying and joined to the first gas permeable sidewall to provide an interior volume;
- wherein at least a portion of the first sidewall includes a first layer of a heat sealable material and a second layer of air permeable material.
2. The vacuum storage bag of claim 1, wherein the first layer comprises low density polyethylene and the second layer comprises high density polyethylene.
3. The vacuum storage bag of claim 2, wherein the first layer and the second layer are in direct contact.
4. The vacuum storage bag of claim 1, wherein the first sidewall has an overall thickness, the first layer comprising between about 5% to about 50% of the overall thickness.
5. The vacuum storage bag of claim 2, wherein the first layer and the second layer are coextensive.
6. The vacuum storage bag of claim 2, wherein the first sidewall further includes a third outermost layer, the second layer is between the first layer and the third layer.
7. The vacuum storage bag of claim 6, wherein the third layer comprises low density polyethylene.
8. The vacuum storage bag of claim 6, wherein the third layer comprises ultra low density polyethylene.
9. The vacuum storage bag of claim 1, wherein the second sidewall is a gas permeable sidewall including a first layer and a second layer.
10. The vacuum storage bag of claim 1, wherein the first sidewall has an overall thickness of about 2.5 mils to about 3.5 mils.
11. The vacuum storage bag of claim 1, wherein the first layer comprises a linear low density polyethylene.
12. The vacuum storage bag of claim 1, further comprising one-way valve element attached to the first or second sidewall and communicating with the interior volume.
13. The storage bag of claim 1, further comprising an opening for accessing the interior volume, first and second interlocking closure strips attached respectively to the first and second sidewalls proximate the opening.
14. The vacuum storage bag of claim 1, wherein at least a portion of at least one inner surface of the first or second sidewalls includes a textured portion.
15. The vacuum storage bag of claim 14, wherein the textured portion is on the inner surface of the first layer of the first sidewall.
16. The vacuum storage bag of claim 15, wherein the textured portion includes a plurality of protruding elongated ridges.
17. The vacuum storage bag of claim 14, wherein the textured portion includes a plurality of raised protuberances rising from the inner surface.
18. The vacuum storage bag of claim 14, further comprising a second textured portion located on an inner surface of the second sidewall.
19. A vacuum storage bag comprising:
- a first flexible sidewall including an inner most layer of low density polyethylene and a second layer of high density polyethylene; and
- a second flexible sidewall including an inner most layer of low density polyethylene and a second layer of high density polyethylene, the second sidewall overlaying and joined to the first sidewall to provide an interior volume.
20. The vacuum storage bag of claim 19, wherein the first and second sidewalls are joined by heat seals formed between the low density polyethylene layer of the first sidewall and the low density polyethylene layer of the second sidewall, the heat seals being formed along a first side edge and a second side edge.
Type: Application
Filed: Jul 5, 2007
Publication Date: Jan 21, 2010
Inventors: Scott Binger (Bridgeview, IL), Michael G. Borchardt (Naperville, IL)
Application Number: 12/375,352
International Classification: B65D 30/08 (20060101);