Freezers, Laboratory, Cryogenic, Liquid Nitrogen
Definition : Freezers that use liquid nitrogen as the cooling and storage agent. Liquid nitrogen storage provides a temperature of -180 degrees Celsius (-292 degrees Fahrenheit) or colder with minimal temperature fluctuations. These freezers typically consist of a chamber with two vessels separated by a vacuum space (the inner vessel for the cryogenic fluid and the outer vessel intended to insulate the cryogenic liquid from the environment); automatic level and cryogenic temperature controls; an external container to replenish the cryogenic fluid; a pressure-relief device; and a pressure-control valve. Cells or tissues are immersed in the liquid nitrogen using appropriate sealed containers, but the use of large volumes (depth) of liquid nitrogen and sealed glass create potential hazards; cross-contamination by virus pathogens via the liquid nitrogen medium has occurred. Liquid nitrogen cryogenic laboratory freezers are used mainly for cell or tissue (e.g., ovum, embryo, bone, cornea) storage for extended periods (typically several years).
Entry Terms : "Liquid Nitrogen Cryogenic Freezers" , "Freezers, Liquid Nitrogen"
UMDC code : 22073