Receptacles – For cryogenic content – Spaced – self-sustaining – inner and outer containers
Reexamination Certificate
2000-12-29
2002-10-22
Coy, Joseph M. (Department: 3727)
Receptacles
For cryogenic content
Spaced, self-sustaining, inner and outer containers
C220S560120, C220S367100, C220S560070
Reexamination Certificate
active
06467642
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The present application is related to the following three patent applications, all of which are specifically incorporated herein by reference, and all of which are being filed concurrently with the present application on the same date: Ser. No. 09/753,195, entitled “SELF-VENTING CAP FOR A NECK OF A DEWAR VESSEL,” Ser. No. 09/753,208, entitled “SPECIMEN CHAMBER FOR A CRYOGENIC SHIPPING CONTAINER,” and Ser. No. 09/753,207, entitled “CONTAINMENT SYSTEM FOR SAMPLES OF DANGEROUS GOODS STORED AT CRYOGENIC TEMPERATURES.”
FIELD OF THE INVENTION
The present invention is in the field of cryogenic shipping containers.
BACKGROUND OF THE INVENTION
To ensure reproducible results in research and biotechnical processes, today's scientists and clinical practitioners have found it necessary to genetically stabilize living cells and preserve the integrity of complex molecules for storage and transport. This is accomplished by containing these materials in enclosures where cryogenic temperatures are continuously maintained at or near liquid nitrogen or vapor phase liquid nitrogen temperatures (77K and 100K, respectively).
Advances in cryopreservation technology have led to methods that allow low-temperature maintenance of a variety of cell types and molecules. Techniques are available for the cryopreservation of cultures of viruses and bacteria, isolated tissue cells in tissue culture, small multi-cellular organisms, enzymes, human and animal DNA, pharmaceuticals including vaccines, diagnostic chemical substrates, and more complex organisms such as embryos, unfertilized oocytes, and spermatozoa. These biological products must be transported or shipped in a frozen state at cryogenic temperatures to maintain viability. This requires a shipping enclosure that can maintain a cryogenic environment for up to 10 days and meet other shipping requirements such as being relatively impervious to mechanical shock and effects of directional orientation.
In addition to the already existing difficulties posed in shipping heat-sensitive biologicals, the International Air Transport Association (IATA) imposed new regulations which became effective in January 1995 pertaining to all shipments that include specimens containing infectious agents or potentially infectious agents. These regulations, endorsed by the US Department of Transportation (DOT) and applicable to all public and private air, sea, and ground carriers, imposed greatly increased requirements upon shipping units to survive extensive physical damage (drop-testing, impalement tests, pressure containment tests, vibration tests, thermal shock, and water damage) without leakage and without fracture of the internal, primary receptacles (vials). Implementation of this regulation further complicated the shipping of frozen biologicals.
Even though bioshippers are currently available using liquid nitrogen as a refrigerant, little innovation has taken place in the design of packaging for low-temperature transport. Current shippers are generally vulnerable to the physical damage and changes in orientation encountered during routine shipping procedures. Additionally, these shippers rarely comply with the IATA Dangerous Goods Regulation (effective January 1995 or as later amended). Commercial vendors have not developed or certified a cost-effective, standardized shipping unit with the necessary specimen capacity and hold time to meet user demands.
One of the main criticisms of current shippers is price, which varies from $500.00 to $1,000.00 or more per unit. This substantially limits their use for the transport of many biologicals. Because of the initial cost and limited production of these containers, they are designed to be reusable. However, the cost of return shipping of these heavy containers is significant, particularly in international markets.
Users also complain about the absorbent filler used in the current dry shippers, which breaks down with continuous use, contaminating the interior of the container. In fact, one large user of these containers has essentially centered their entire shipping operation around cleaning the broken down absorbent material from the inside of these containers after each use.
Another problem cited by users of currently available dry shippers relates to the functional hold time versus static hold time. Static hold time pertains to a fully charged shipper with no heat load, sitting upright, e.g., essentially not in use. Functional hold time refers to the fully charged shipper in use and containing samples, e.g., in the process of being handled and transported. Even though the static hold time is often promoted as being 20 days, if the container is tilted or positioned on its side, the hold time diminishes to hours as opposed to days. This occurs because the liquid nitrogen transitions to the gaseous (vapor) phase more rapidly resulting in outgassing. The liquid nitrogen can also simply leak out of the container when it is positioned on its side.
The current cryogenic containers are promoted as being durable because they are of metal construction. However, rugged handling frequently results in the puncturing of the outer shell or cracking at the neck, resulting in loss of the high vacuum insulation. This renders them useless. The metal construction also adds to the weight of the container, thereby adding substantially to shipping costs.
Thus, there is a need for an improved cryogenic container that can be used to ship biologicals safely, reliably, and economically.
U.S. Pat. No. 6,119,465 seeks to meet this need by using unique, lightweight, low-cost, durable composites and polymers in a semi-disposable vapor phase liquid nitrogen bioshipper. This is accomplished in an inherently simple, reliable, and inexpensive device that will result in reduced shipping costs, enhanced reliability and safety, and fewer service requirements.
The present invention builds upon the framework laid by U.S. Pat. No. 6,119,465, the disclosure of which is specifically incorporated herein by reference. This is done by use of a cryogenic shipping container that has many significant advances over what is disclosed in our earlier patent. The end result is a much improved cryogenic shipping container that is more economical while still being reliable.
SUMMARY OF THE INVENTION
The present invention is generally directed to a portable, insulated shipping container. The shipping container has an outer shipping container shell and a support assembly for holding a dewar vessel within the outer shipping container shell and providing impact and vibration resistance to the dewar vessel. The dewar vessel has an inner vessel that holds a specimen chamber and plastic foam between its inner wall and the specimen chamber. The specimen chamber allows liquid cryogen to pass through it into the plastic foam, allows liquid cryogen in a vapor phase liquid state to pass from the plastic foam into it, and acts as a filter to prevent particles or fragments of the plastic foam from entering into it. It is preferred that the specimen chamber is an open-celled porous thermoplastic material that is cryogenically compatible, and it is especially preferred that it be an aerated polypropylene foam. It is preferred that the plastic foam is an open cell plastic foam, and it is especially preferred that it be a phenolic foam.
In a first, separate group of aspects of the present invention, the plastic foam can hold a normal charge of liquid cryogen in a dry vapor state regardless of the container's spatial orientation. The plastic foam can be made of multiple foam segments having a maximum thickness less than a critical height with each segment being separated by a capillarity separation layer. The thickness of the foam segments is preferably selected so that the head pressure of the plurality of foam segments will not cause liquid cryogen to ooze or flow out of the foam segments when their spatial orientation is changed. This thickness can be less than approximately four inches. The foam can occupy substantially all of the volume between
Emmel Gregg
Giesy Kevin
Mullens Patrick L.
Thomas Christy
Anderson Ray L.
Coy Joseph M.
LandOfFree
Cryogenic shipping container does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cryogenic shipping container, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cryogenic shipping container will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2967324