Flexible bags – Inflatable
Reexamination Certificate
1998-09-17
2003-02-04
Pascua, Jes F. (Department: 3727)
Flexible bags
Inflatable
C383S110000, C206S522000
Reexamination Certificate
active
06513974
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to thermally-insulated shipping containers and, more particularly, to shipping containers that are selectively inflatable. More specifically, the present invention relates to a pair of film layers having opposed reflective surfaces, and an optionally-interposed film baffle layer, that together define an inflatable envelope in the form of a flexible insulating bag.
2. Description of the Prior Art
In the transportation and distribution of products, the “shipping environment” is defined by both the product and the package. While the corrugated fiber board boxes, steel drums, wooden crates, and pallets have not changed significantly over the past 80 years, the shipping requirements of the products have changed with each new generation of both product and shipping technology. As a result, packaging materials have improved to meet the demands of the new technology.
Refrigerated transportation at one time meant a horse-drawn wagon packed with ice and straw. Super-cooled gases and microprocessor-controlled motors have replaced the earlier, primitive refrigeration techniques. Reliable, temperature-controlled, surface transportation is now available to and from almost anywhere in the world. Trucks and ocean container shipping utilize positive, mechanical refrigeration systems to retard spoilage in transit.
Such surface transportation is relatively slow, and the shipped goods must have a correspondingly long shelf life. However, many temperature-sensitive products, such as perishable foodstuffs, are time-sensitive as well. Successful long-distance shipping is only feasible where transportation time can be minimized.
Servicing a worldwide food market required yet another technological development—the generous cargo holds of newer, wide-body passenger jet aircraft in the late 1960's and early 70's. The drop in airfreight rates heralded by these new jets for the first time permitted the cost-effective transportation of perishable, medium-value commodities such as meat, seafood, and fresh produce.
Traditionally, such perishable foodstuffs, as well as pharmaceuticals, are cooled prior to shipment, then placed within a thermal insulating material, and shipped with only a modicum of ice or refrigerant to absorb the heat that flows through the insulation. For many years, molded expanded polystyrene (“EPS”) containers have been the thermal insulating material of choice. The perishable goods are placed within the EPS containers, which are then in turn placed within small, corrugated shipping boxes.
EPS containers have been widely used since the lowered airfreight rates first made this form of shipment economically practical. While providing satisfactory insulation qualities as well as being light in weight, EPS also presents several negative characteristics to the shipping industry. EPS is an “expanded,” non-compressible material, and consists of a very large number of small air bubbles formed in a polystyrene plastic matrix. EPS's poor volume efficiency increases shipment costs when transporting the empty containers to the location of their use, as well as causing increased warehousing costs when stored in inventory prior to use.
While providing reasonable protection from shock impacts during transit, EPS has poor resistence to the application of puncture and shear-loading. EPS easily fractures, requiring the use of an additional plastic liner bag when shipping products with a liquid component, such as ice-chilled, fresh seafood. The lack of such an additional plastic liner risks liquid leakage from the EPS container during shipment, and the resultant expensive damage to aircraft cargo holds or other corrosion-sensitive shipping environments.
In an effort to avoid EPS and its negative characteristics, a number of shippers have attempted to make use of metalized, radiant barrier bags. Relying on the property of shiny, metalized coatings to reflectively radiate heat energy, such products have found only marginal success as insulated packaging. Although reducing warehousing and breakage expenses, as well as enjoying lower manufacturing costs, many shippers have determined that such radiant bags do not control temperatures over a sufficiently long period of time.
Ideally, it would be desirable to provide an insulative system having a reliable thermal performance over extended time periods (at least 48 hours), which is leakproof, can be shipped and stored in a manner requiring less space than EPS, and that is fabricated out of materials and in a manner that remains cost-competitive with the EPS insulated box product.
It is thus an object of the present invention to provide a flexible insulating bag of collapsible design having equal thermal insulation to that provided by EPS. The reduction in storage and shipping volume of the collapsible bag over the EPS container translates into lower costs, enabling world-wide marketing by a single source of supply, permits distributors to economically inventory large quantities of different-sized shipping container bags, and permits shippers to maintain a greater inventory, requiring fewer deliveries as well as economically ship to remote packing locations to cost-effectively service the fresh market from more remote source regions.
It is a further object of the present invention to provide two reflective surfaces, one inside the hot face to function as a low-emissivity surface and one on the inside of the cold face, functioning as a radiant barrier.
It is another object of the present invention to provide an inflatable design, permitting collapse of the insulating container for efficient storage, and, when inflated, creating an airspace adjacent the reflective surfaces to empower a further reduction in heat flow, either by lower emissivity or greater reflectivity.
It is another object of the present invention to provide an alternate intermediate baffle design that incorporates the aforementioned double radiant barrier, in an insulating system that bisects the insulating, inflated chamber in a manner that further inhibits convective heat transfer.
It is a still further object of the present invention to fabricate such an insulating bag in a manner that utilizes a minimum number of processing steps to form all air-containing and shape-controlling structural features of the insulating bag, including the incorporation of a flat inflation valve and a closure securement system, such as a zip-closure.
It is another object of the present invention to include one or more uninflated gussets within a bottom panel of the insulating bag to receive and collect melted ice water and any liquid leakage from the shipped products, separating such liquid from the products enhancing freshness and minimizing contamination.
It is another object of the present invention to fabricate the flexible insulating bags out of film materials using rf welding to enable reliable, high volume manufacturing at low per-unit cost.
It is another object of the present invention to provide a flexible insulating bag that is inflated with air for normal insulating values, or may be optionally inflated with an inert, low conductivity gas, such as argon, to further enhance insulating performance.
It is another object of the present invention to permit the collapse of a used insulating bag by deflating same, reducing disposal costs, whether shipped for recyling or on the basis of a reduced amount of landfill volume required if discarded.
SUMMARY OF THE INVENTION
These and other objects of our invention are provided by a flexible insulating bag that utilizes an inflatable wall panel construction. A pair of opposed flexible plastic film layers form the walls, and they are inexpensively attached together by rf (radio-frequency) welding. The intricate pattern of attachment seams that connect the pair of film layers is used to define the individual inflatable wall panels, as well as the overall shape of the insulating bag upon its inflation.
The inflatable walls significantly reduce conductive heat losses through th
Malone Thomas G.
McGraw John J.
Kenehan & Lambertsen, Ltd.
Lambertsen John C.
Pascua Jes F.
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