AU721293B3

AU721293B3 - Apparatus for super freezing and storing materials

Info

Publication number: AU721293B3
Application number: AU14807/00A
Authority: AU
Inventors: Eric B Graham
Original assignee: Coldwave Systems LLC
Current assignee: Coldwave Systems LLC
Priority date: 1997-10-20
Filing date: 2000-02-01
Publication date: 2000-06-29
Anticipated expiration: 2004-10-16

Description

Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A PETTY PATENT (original) Name of Applicant: Coldwave Systems LLC Actual Inventor: Eric B Graham Address for Service: MADDERNS, 1st Floor, 64 Hindmarsh Square, Adelaide, South Australia, Australia Invention Title: APPARATUS FOR SUPER FREEZING AND STORING

MATERIALS

The following statement is a full description of this invention, including the best method of performing it known to us.

APPARATUS FOR SUPER FREEZING AND STORING MATERIALS

BACKGROUND

1. Field of Invention This invention relates to freezing and storing materials in self-contained shipping containers at below -50* C. In particular, this invention relates to super freezing and storing perishable materials such as fish.

2. Background Commercial fishing is a worldwide enterprise generating billions of dollars in sales on an annual basis. With modemrn shipping and storage technology, fish caught nearly anywhere in the world can 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 cannot be frozen using conventional equipment, without adversely affecting the quality, color and taste thereof. For this reason, fish intended for use as sushi generally must be caught locally so it can be brought to market relatively quickly without freezing. This necessity has tended to limit the supply of fish available for sushi to effectively increase the price thereof relative to frozen fish. This phenomenon tends to produce a relatively large disparity between the price of sushi-grade fish and non-sushi grade 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 thus a substantially lower market value therefor), and transported the product at cryogenic 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 r 2 tVAr Odi with sushi-grade product. To achieve this, expensive and specialised equipment has been required at the point of freezing (a local fishing port).

SUMMARY OF THE INVENTION According to the invention there is provided portable apparatus for freezing and storing fish at a super-frozen temperature of less than or equal to about to preserve the fish at sushi-quality, the apparatus comprising: a container having super-insulated walls and a size and shape of a modular ISO shipping container; a refrigeration system disposed integrally with said container, said refrigeration system being adapted to freeze product disposed within said container to the super-frozen temperature; said apparatus adapted for being shipped to a destination for deployment at the destination to freeze and store fish at the super-frozen temperature.

Preferably, said apparatus is adapted for being shipped to a destination on board a vehicle adapted to receive modular ISO containers thereon.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a section of a super freezer/storage container with super-insulated walls and a CO2 distribution system.

FIG. 2 shows the wall section of a standard ISO shipping container with standard insulation value, and the additional insulation which, when added, will create the super insulated container's insulative value. Standard r-value of a shipping container is in the range of 15 to 20. The super container shown in this figure has r-values of or more.

FIG. 3 shows a section of a super freezer/storage container with super insulated fjRZN- lIs a freezer section and a separate storage section, a cryogenic liquid supply tank, v 3 thermostatic valves for the temperature controlled flow of the cryogenic liquid, an electric control panel to turn the system on and off and set the desired interior air temperature, fans for increased heat transfer during the freezing process and temperature probes to read the air temperature inside the two sections.

PREFERRED EMBODIMENTS

DESCRIPTION

Herein we describe a specific embodiment which is the preferred embodiment. While the invention is susceptible to various modifications and alternative forms, this specific and preferred embodiment is shown by way of the drawings and the detailed description herein described. It should be understood, however, that there is no intent to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1, a super freezer/storage container is constructed beginning with a commercially available insulated ISO shipping container built with or designed to support a mechanical refrigeration unit. The standard refrigeration unit was removed from the nose 1. The nose 1 was closed and insulated with approximately to 25 mm (8 to 10") of polyurethane insulation foam 2. Ten millimetres (4 inches) of polyurethane foam insulation was added to the bottom side 3 of the container, between and around the cross members, the walls and ceiling 4 on the inside of the container and the doors 5 of the container. Additional closure gaskets were added around the seal of the doors 6 after the insulation was added to insure a proper seal.

The container is provided with a hinged vent door 7 which automatically opens when the pressure inside the container increases. The vent door 7 releases the pressure as cryogenic liquid is added and as the cryogenic liquid sublimates. This was installed in the nose 1 of the container about one inch down from the top of the container box. A cryogenic liquid spray header was installed. The spray head is wn as a Transnow CO 2 sprayhead 8 and is the subject of U.S. Pat. No. 4,640,460.

4A- -o4 The sprayhead was installed in the roof of the super insulated container and connected to a valve 9 on the outside of the container where the liquid CO 2 line 10 is connected. The Transnow CO 2 spray head has properties and advantages such that it provides the greatest ratio of liquid CO 2 to solid CO 2 product, thus operating at highest available efficiency and reducing the refrigeration cost. It should be understood that there is no intention to limit the scope of the invention to use with a Transnow CO 2 spray head as any cryogenic liquid distribution system or solid dry ice could be used as well.

A key feature of the super freezer/storage container is the increased r-value of its walls. FIG. 2 is a cross section of the container wall showing the additional insulation 11.

FIG. 3 shows a cross-section and key features of a freezing and storage container.

This container is a standard ISO insulated container to which has been added a vent door 12, at least one interior wall 13 and connecting door 14 and foam insulation 15 is added to all walls and doors such to form super-insulated walls and doors increasing the r-value. A cryogenic temperature control system is added consisting of refrigerant piping 16, temperature probes 17, thermostatic valves 18, an electric control panel 19, and cryogenic storage facility

OPERATION

The product or material to be frozen is loaded into a freezing section of the freezing and storage super-insulated container of FIG. 3 which has been pre-cooled to -600 C.

It is allowed to cool to ambient temperature and is thus transformed into the superfrozen state. The super-frozen product or material is then transferred to a storage section of the container to await transfer or shipping of the freezing/storage container.

Optionally, the product or material to be shipped in the super-frozen state is ~t ansferred from the storage container and loaded into a separate super insulated container which has been precooled to -60 C. The loading proceeds in the same manner in that they are loaded into a standard shipping container. In most cases the products are bulk loaded by hand, one on top of the other. The amount of product that should be loaded is also a factor of how long the shipping time will be and the amount of CO 2 solid is needed. However, once the pre-frozen product or material has been loaded into a super insulated container, this super insulated container provides an atmosphere in which the CO 2 is distributed and surrounds the frozen products inside the super insulated container. As the CO 2 is being distributed a large amount of pressure is being blown into the container box. The effect is something like a blizzard with very high winds. Thus the CO 2 snow will fill air pockets and crevices, although the majority of the snow will be piled on top of the products. Once the product is loaded into the super insulated container and injected with the CO 2 the super insulated container can be handled the same way all other dry cargo shipping containers are handled. This is in distinction to frozen shipping containers which require monitoring and electrical power hookups. Before injecting the CO 2 a calculation is performed to determine the amount of CO 2 that will be required to maintain the super frozen state of the product or material until it arrives at its destination or until additional CO 2 can be added to the super insulated container.

This calculation is based upon the insulative value of the super insulated container, the amount (weight) of pre-frozen products or materials which will be loaded, the relative heat factor of the products or materials and the amount of time the product will be in transit. The super insulated container can be loaded onto a truck chassis and transported to the point of departure such as a ship port, rail yard or other transportation depot. It is then taken off of the truck and put into a holding area awaiting loading onto the ship, train or other conveyance. From the moment the super insulated container is loaded onto the conveyance until its arrival at the destination, no special monitoring or handling is required by the shipper or the shipping line.

en the container arrives at its destination, the interior temperature of the super RsuA"'ed container can be tested and, if necessary, additional CO 2 can be added to 6 G provide extra storage time. The products can also be unloaded at this point and placed in cold storage at the destination.

EXAMPLE

To the super freezer/storage container described above and shown in FIG. 3 were added five 1 hp fans to the rear area, and the spray header was separated into two sections. Two temperature probes were added (one in each compartment) to monitor the air temperature. The temperature probes were connected to an electric switch box which allows the desired air temperature to be set inside each compartment. The switches and probes are connected to valves which open and close based on desired temperature setting and the actual air temperature inside each compartment.

Fresh tuna fish were loaded onto racks and the racks were placed inside the freezing section of the container. The doors were closed and the fans and nitrogen supply switches were turned on. Wire temperature probes were placed inside the core meat of the fish. When core temperature reaches around -50' C. everything is turned off and the doors of the container were opened and nitrogen gas was allowed to escape.

The fish were taken off the racks and glazed by dipping in water for a few seconds.

The glazed fish were then loaded into the super insulated storage area.

Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Various other embodiments and ramifications are possible within its scope.

Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.

Claims

1. A portable apparatus adapted for freezing and storing fish at a super-frozen temperature of less than or equal to about -50 0 to preserve the fish at sushi-quality, the apparatus comprising: a container having super-insulated walls and a size and shape of a modular ISO shipping container; a refrigeration system disposed integrally with said container, said refrigeration system being adapted to freeze product disposed within said container to the super-frozen temperature; said apparatus adapted for being shipped to a destination for deployment at the destination to freeze and store fish at the super-frozen temperature.

2. The apparatus of claim 1, wherein said apparatus is adapted for shipment to a destination on board a vehicle adapted to receive modular ISO containers thereon.

3. The apparatus of claim 1 or claim 2, wherein said container has an insulation r-value of 30 or more. Dated this 11th day of April, 2000. COLDWAVE SYSTEMS, L.L.C. By its Patent Attorneys MADDERNS