Refrigeration – Storage of solidified or liquified gas – Spraying of cryogen
Reexamination Certificate
2002-05-17
2004-09-14
Doerrler, William C. (Department: 3744)
Refrigeration
Storage of solidified or liquified gas
Spraying of cryogen
C062S223000, C062S064000
Reexamination Certificate
active
06789391
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a method and apparatus for shipping, storing and freezing super-frozen perishable materials. This invention more particularly relates to a modular cooler for removably interfacing with a shipping container and maintaining the interior of the container below −50° C.
(2) Background Information
Commercial fishing is a worldwide enterprise generating billions of dollars in revenue annually. With modem shipping and storage technology, fish caught nearly anywhere in the world may be efficiently frozen and subsequently transported to almost any market in the world for consumption thereof
Particular products however, do not lend themselves to conventional freezing and shipping methods. In particular, fish intended for consumption in an uncooked or raw state such as sushi, generally may not be frozen using conventional equipment, without adversely affecting the quality (i.e., the color and/or taste) thereof. For this reason, fish intended for use as sushi tends to be caught locally so it may be brought to market relatively quickly without freezing. This necessity has tended to limit the supply of fish available for sushi and effectively increased the price thereof relative to frozen fish. There therefore tends to be a relatively large disparity between the price of sushi-grade fish and non-sushi grade (i.e., frozen) fish in the marketplace.
In a recent attempt to address this disparity, some commercial fishing enterprises have harvested fish, such as tuna and the like, in areas of the world where there is little local demand for sushi-grade product, and transported the product at cryogenic (i.e., super-cooled) temperatures of less than −40 degrees C. to the sushi markets. It has been found that at these temperatures tuna and the like maintain suitable freshness for sushi purposes to thus retain the relatively high quality and premium prices associated with sushi-grade product. This approach has generally required dedicated use of cargo ships known as super carrier vessels, outfitted with specialized refrigeration equipment specifically designed to maintain a constant cryogenic temperature of about −60 degrees C. The expense of such vessels typically dictates their use only when a substantially full shipment of approximately 100 metric tons (100,000 kilograms) or more of product is available for shipment. Accordingly, in order to satisfy this relatively high minimum volume requirement, such ships must generally remain at port or in the vicinity of tuna fishing fleets for extended periods of time as the fish are harvested and prepared for shipment. Disadvantageously, this aspect generally limits the number of trips from the fishing ports to the sushi markets to approximately one or two trips per year. For many perishable products this high volume requirement and low trip frequency renders this approach impractical. For many products that are in demand, the time required for shipment on a super carrier vessel, often several months from harvest to arrival at the destination, further makes such a shipping method undesirable.
Smaller shipments of conventionally frozen (i.e., 0 to −26 degrees C.) product have been shipped utilizing standard ISO containers on conventional transport ships. These ISO containers are relatively plentiful and the conventional transport ships travel on a relatively frequent basis to most desired destinations. These containers are typically refrigerated by use of mechanical refrigeration units associated with each individual ISO container. These refrigeration units, however, have not been capable of providing refrigerated temperatures of less than about −25 degrees C. Moreover, such mechanical units are prone to mechanical failure, in which about 5 to 10 percent of shipments are lost due to spoilage primarily due to mechanical breakdown and human error. Such units are also relatively expensive, generally costing on the order of $8000 to $10,000 for the container, an additional $10,000 to $12,000 for each refrigeration unit plus another $10,000 to $12,000 for an electric generator (i.e., genset) to provide electric power for the refrigeration unit. A further drawback of these mechanically refrigerated containers is that they typically must be transported on ships equipped for “reefer” (i.e., refrigerated) shipments, i.e., on ships capable of providing a continuous supply of fuel and/or electricity to the containers and including technicians capable of servicing the units in the event of a failure en-route. Shipping rates for such reefer containers tend to be considerably higher than rates for “dry” containers (i.e., those not requiring such services) of comparable size and weight.
Moreover, it has also been recognized that shipping rates for standard ISO shipping containers are significantly lower than for similarly sized and shaped containers, which are not ISO compliant. For example, a standard 40 foot ISO shipping container which may cost $2,000 (U.S.) to ship, may cost up to $15,000 if not ISO compliant. This discrepancy is due largely to the ability to stack shipping containers, which have been certified to comply with ISO standards with respect to size, shape, structural integrity, and/or ability to interlock to one another.
Graham, in U.S. Pat. No. 6,003,322, which is fully incorporated herein by reference and hereafter referred to as the '322 patent, discloses an apparatus and method for shipping product disposed at a super-frozen temperature of less than or equal to about −50 degrees C. The apparatus desirably includes an ISO certified container having walls insulated to an r-value greater than or equal to about 20 and a spray head disposed within the container to spray cryogenic fluid. The container is further selectively sealable to form a self-contained, dry module capable of receiving product at the super-frozen temperature and maintaining the product at super-frozen temperature during shipment thereof.
Notwithstanding the substantial improvements disclosed in the Graham patent, there remains a need for an improved apparatus and method for shipping product disposed at super-frozen temperatures, and in particular there exists a need for those providing for increased versatility in shipping product at super-frozen temperatures.
SUMMARY OF THE INVENTION
In one aspect, the present invention includes a modular cryogenic cooler for removably interfacing with an insulated container, the container being configured for maintaining an interior of the container at a super-frozen temperature of less than or equal to about −50 degrees C. The cryogenic cooler includes a modular connector configured for removable engagement with the container, a cryogenic fluid transport module coupled to the modular connector, the transport module having a cryogenic fluid supply coupling. The supply coupling is couplable to a cryogenic fluid source, and the transport module is configured to selectively feed cryogenic fluid from the source to the container. A controller is operationally coupled to the transport module.
In another aspect, this invention includes a portable apparatus configured for freezing and storing fish at a super-frozen temperature of less than or equal to about −50 degrees C., to preserve the fish at sushi-quality. The apparatus includes a container having an interior and a modular cryogenic cooler removably engaged with the container. The modular cryogenic cooler includes a modular connector sized and shaped for removable engagement with said container;
a cryogenic fluid transport module coupled to said modular connector, and having a cryogenic fluid supply coupling, and a controller operationally coupled to the transport module. The supply coupling is couplable to a cryogenic fluid source, and the transport module is configured to selectively feed cryogenic fluid from the cryogenic fluid source to the container.
In yet another aspect, this invention includes a method for storing product disposed at a super-frozen temperature
Graham B. Eric
McCormick Stephen A.
Doerrler William C.
Sampson & Associates P.C.
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