The present invention generally relates to vacuum packaging. More particularly, the invention is directed to clamps, systems, and methods for evacuating and hermetically sealing bags.
Vacuum packaging involves removing air or other gases from a storage container and then sealing the container to prevent the contents from being exposed to the air. Vacuum packaging is particularly useful in protecting food and other perishables against oxidation. Oxygen is a main cause of food spoilage and contributes to the growth of bacteria, mold, and yeast. Accordingly, vacuum packaged food often lasts three to five times longer than food stored in ordinary containers. Moreover, vacuum packaging is useful for storing clothes, photographs, silver, and other items to prevent discoloration, corrosion, rust, and tarnishing. Furthermore, vacuum packaging produces tight, strong, and compact packages to reduce the bulk of articles and allow for more space to store other supplies.
Conventional vacuum packaging bags include two panels attached together with an open end. Typically, the panels each include two or more layers. The inner layer can be a heat sealable material, and the outer layer can be a gas impermeable material to provide a barrier against the influx of air. The plasticity temperature of the inner layer is lower than the outer layer. Accordingly, the bag can be heated to thermally bond the inner layer of each panel together to seal the bag without melting or puncturing the outer layer during the heat sealing cycle.
A conventional vacuum packaging process includes depositing the object 79 into the bag 70 and positioning an open end 71 of the bag 70 proximate to the lower trough 84 of the vacuum packaging appliance 80. Next, the lid 90 pivots downward to form the vacuum chamber around the open end 71 of the bag 70. The vacuum pump then removes gas from the vacuum chamber and the interior of the bag 70, which is in fluid communication with the vacuum chamber. After the gas has been removed from the interior of the bag 70, the heating element 88 heats a strip of the bag 70 proximate to the open end 71 to melt the inner layer of each panel and thermally seal the bag 70.
One problem with conventional vacuum packaging methods is that thermally sealed bags cannot be resealed and reopened numerous times. More specifically, a thermally sealed bag is opened by cutting the bag below the seal. The bag can be subsequently resealed; however, each time the bag is reopened, another portion of the bag is cut off. Another problem with conventional vacuum packaging methods is that the bags must have at least two layers, each with a different plasticity temperature. The plasticity temperature of the layers is different so that the inner layer of the panels can be heated and bonded together without puncturing or melting the outer layer. Bags having panels with two different layers are expensive and complex to manufacture. Accordingly, there is a need to improve the process of vacuum packaging bags.
A. Overview
The present invention is directed to clamps, systems, and methods for evacuating and hermetically sealing bags. In the following description, numerous specific details are provided of particular clamp configurations to provide a thorough understanding of and an enabling description for embodiments of the invention. Those of ordinary skill in the art, however, will recognize that the invention can be practiced without one or more of the specific details explained in the following description. In other instances, well-known structures and operations are not shown or described in detail to avoid obscuring aspects of the invention.
One aspect of the invention is directed to clamps for substantially evacuating and hermetically sealing bags having an interior region and an open end. In one embodiment, a clamp includes a first clamp portion having a first chamber portion and a second clamp portion having a second chamber portion. The second clamp portion is movable relative to the first clamp portion between a released position and a clamped position. When the second clamp portion is in the clamped position, the first and second chamber portions define a vacuum chamber for removing gas from the bag. The clamp further includes a valve carried by the first or second clamp portion to control the flow of gas into and/or out of the vacuum chamber. In one aspect of this embodiment, the first clamp portion is pivotably coupled to the second clamp portion. Alternatively, the first clamp portion can further include a slot and the second clamp portion can be sized and configured to slide at least partially into the slot. In another aspect of this embodiment, the clamp further includes a seal coupled to the first or second clamp portion. The seal circumscribes the vacuum chamber.
In another embodiment, a clamp includes a first clamp portion having a recess to receive the open end of the bag and a second clamp portion having a surface. The second clamp portion is configured to selectively engage the first clamp portion so that the surface and the recess define a vacuum chamber. The vacuum chamber is configured to be in fluid communication with the interior region of the bag when the open end of the bag is received in the vacuum chamber. The clamp further includes a valve carried by the first or second clamp portion to control the flow of a gas into and/or out of the vacuum chamber. In one aspect of this embodiment, the valve is a one-way valve to allow gas in the interior region of the bag to be exhausted from the vacuum chamber. The clamp can further include a release valve coupled to the first or second clamp portion to selectively allow gas from an ambient environment to flow into the vacuum chamber.
Another aspect of the invention is directed to systems for hermetically sealing bags having an interior region and an open end. In one embodiment, a system includes a clamp having a first chamber portion and a second chamber portion. The second chamber portion is movable relative to the first chamber portion between a released position and a clamped position. The first and second chamber portions define a vacuum chamber configured to be in fluid communication with the interior region of the bag when the second chamber portion is in the clamped position and the open end of the bag is received in the vacuum chamber. The system further includes a valve carried by the first or second chamber portion to control the flow of gas out of the vacuum chamber, an exhaust line coupleable to the valve, and a vacuum pump coupleable to the exhaust line to remove the gas from the vacuum chamber and the interior region of the bag.
Another aspect of the invention is directed to methods for hermetically sealing bags with clamps. The bags have an open end and an interior region, and the clamps have a first clamp portion and a second clamp portion. In one embodiment, a method includes clamping a portion of the bag with the first and second clamp portions to hermetically seal the bag with the open end received in a vacuum chamber defined by the first and second clamp portions. The vacuum chamber is in fluid communication with the interior region of the bag and hermetically sealed from an external environment. The method further includes removing gas from the vacuum chamber and the interior region of the bag and storing the clamped and sealed bag with the clamp.
B. Embodiments of Systems for Evacuating and Hermetically Sealing Bags
The clamp 110 includes a first clamp portion 120 and a second clamp portion 140 movably coupled to the first clamp portion 120 to hermetically seal the bag 170. In the illustrated embodiment, the first clamp portion 120 is pivotably coupled to the second clamp portion 140 by a hinge 118. Accordingly, the first clamp portion 120 pivots relative to the second clamp portion 140 between a released position (shown in
In the illustrated embodiment, the first clamp portion 120 includes an inner surface 130 and a recess 124 in the inner surface 130 to receive an open end 171 of the bag 170. The recess 124 includes a bottom surface 126 and a plurality of side walls 128. The recess 124 has a generally constant depth and a length L corresponding to a width W of the bag 170. More specifically, the length L of the recess 124 is greater than the width W of the bag 170 so that the open end 171 of the bag 170 can be received at least partially in the recess 124. In other embodiments, the depth can vary across the length L and/or the width of the recess 124. The first clamp portion 120 of the illustrated embodiment further includes a seal 132 attached to the inner surface 130. The seal 132 circumscribes the recess 124 to hermetically seal the vacuum chamber of the clamp 110. The seal 132 can be made of an elastomeric or other flexible material to form a seal around the bag 170 when the bag 170 is positioned between the first and second clamp portions 120 and 140. In one embodiment, the seal 132 and the first clamp portion 120 are made of food-safe and washable materials so that the clamp 110 can be used with bags containing foodstuffs.
In the illustrated embodiment, the second clamp portion 140 includes an inner surface 150 and a recess 144 in the inner surface 150. The recess 144 includes a bottom surface 146 and a plurality of side walls 148, and is generally aligned with the recess 124 in the first clamp portion 120 when the first and second clamp portions 120 and 140 are in the clamped position. The second clamp portion 140 further includes a seal 152 attached to the inner surface 150 and circumscribing the recess 144. The recess 124 and the seal 132 of the first clamp portion 120 form a first chamber portion 122, and the recess 144 and the seal 152 of the second clamp portion 140 form a second chamber portion 142. When the first and second clamp portions 120 and 140 are in the clamped position, the first and second chamber portions 122 and 142 define a vacuum chamber 112 to remove gas from an interior region 172 of the bag 170.
In other embodiments, the first clamp portion 120 and/or the second clamp portion 140 may not include a recess. For example, in one embodiment, the inner surface 150 of the second clamp portion 140 does not include the recess 144, and consequently the seal 152 and the inner surface 150 form the second chamber portion 142. In additional embodiments, the first chamber portion 120 and/or the second chamber portion 140 may not include seals or may include seals with other configurations. In other embodiments, the clamp 110 can further include a removable trough disposed within one of the recesses 124 and 144 to collect liquids and other materials that are removed with the gas from the interior region 172 of the bag 170. In additional embodiments, the vacuum chamber can be independent of the first and second clamp portions 120 and 140. For example, the vacuum chamber can be formed by a separate member disposed within or located external to the first and second clamp portions 120 and 140.
The clamp 110 of the illustrated embodiment further includes a valve 160 (shown schematically) in fluid communication with the recess 144 and the exhaust line 198 to control the flow of gas into and/or out of the vacuum chamber 112. The valve 160 can be disposed between an outer edge 154 and the recess 144 of the second clamp portion 140 or carried by the first or second clamp portion 120 or 140 at another position. In additional embodiments, the valve 160 may be external to and spaced apart from the clamp 110, but still in fluid communication with the vacuum chamber 112. In any of these embodiments, the valve 160 can be a one-way valve to permit the vacuum pump 180 to draw gas out of the vacuum chamber 112, but not allow gas to flow from the ambient environment into the vacuum chamber 112. In other embodiments, the valve 160 can selectively permit gas to flow into the vacuum chamber 112 from the ambient environment to facilitate pivoting of the first and second clamp portions 120 and 140 from the clamped position to the released position, as described in detail below with reference to
In one aspect of this embodiment, the clamp 110 tends to remain in the clamped position after the interior region 172 of the bag 170 and the vacuum chamber 112 have been evacuated because of the difference in pressure outside and inside the clamp 110. More specifically, because the ambient pressure outside the clamp 110 is greater than the pressure inside the vacuum chamber 112, an external force is required to pivot the first and second clamp portions 120 and 140 from the clamped position to the released position. In other embodiments, such as the embodiment described below with reference to
One feature of the clamp of the illustrated embodiment is that the clamp can seal and release a bag repeatedly without consuming or damaging the bag. An advantage of this feature is that the life of the bag is significantly extended, and accordingly the cost associated with replacing the bag is reduced. Prior art devices thermally seal bags by bonding the inner layers of the panels together. To open thermally sealed bags, the bags must be cut, which damages and consumes a portion of the bags. Consequently, thermally sealed bags have a limited life and must be replaced frequently.
Another feature of the clamp of the illustrated embodiment is that the clamp seals bags with a single layer and bags with multiple layers. An advantage of this feature is that the clamp can be used with a wide variety of bags. Many prior art devices require that bags have at least two layers with different plasticity temperatures so that the inner layer of the bags can be thermally sealed without damaging the outer layer. These bags with multiple layers are more expensive and complex to produce.
C. Other Embodiments of Clamps
The clamp 310 of the illustrated embodiment further includes a securing device 364 to selectively lock the first and second clamp portions 320 and 340 in the clamped position. The securing device 364 includes a support member 366 attached to the first clamp portion 320 and an engagement member 368 projecting from the support member 366. The support member 366 can be made of a flexible material to bend around the first and second clamp portions 320 and 340 and lock the clamp 310 in the clamped position (as shown in
The clamp 310 can further include a release valve 362 (shown schematically) carried by the second clamp portion 340 to allow ambient air to flow into the vacuum chamber 312 to facilitate moving the first and second clamp portions 320 and 340 from the clamped position to the released position. As described above, after the gas is evacuated from the vacuum chamber 312, the pressure outside the clamp 310 is greater than the pressure within the vacuum chamber 312. Because of the pressure differential, a significant force is required to move the first clamp portion 320 relative to the second clamp portion 340. The pressure differential can be reduced or eliminated by flowing ambient air into the vacuum chamber 312, thereby reducing the force required to move the first and second clamp portions 320 and 340 from the clamped position to the released position. In other embodiments, the clamp 310 may not include a release valve 362 or the valve 160 can also function as a release valve.
In additional embodiments, the clamp 410 can include a securing device to lock the second clamp portion 440 in the clamped position. For example, the second clamp portion 440 can have a taper so that an upper portion 441 has a greater width than a lower portion 443 to create a frictional fit in the second slot 425. In other embodiments, the second clamp portion 440 can include a handle to allow a user to easily remove the second clamp portion 440 from the second slot 425.
D. Embodiments of Vacuum Packaging Appliances for Use with Clamps
The lid 690 can be movable between an open position, in which the clamp 610 can be placed into the appliance 680, and a closed position (shown in
In the illustrated embodiment, the clamp 610 is generally similar to the clamp 410 described above with reference to
The clamp 610 further includes a one-way valve 660 (shown schematically) carried by the first clamp portion 620 and in fluid communication with the vacuum chamber 612. The one-way valve 660 allows gas to flow from the vacuum chamber 612 to the lower trough 684. Accordingly, when the clamp 610 is positioned in the vacuum chamber of the vacuum packaging appliance 680, the vacuum pump 692 can remove gas from the interior of the bag 170. In other embodiments, the clamp 610 can have other configurations, including configurations similar to the clamp 110 described above with reference to
From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.
This application claims the benefit of Brakes U.S. Provisional Patent Application No. 60/490,364, filed Jul. 24, 2003, which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60490364 | Jul 2003 | US |