US Patent 8015841 Cryogenic refrigeration system for lyophilization

A cryogenic refrigeration system includes a cryogenic heat exchanger system adapted for vaporizing a liquid cryogen and using the gaseous cryogen to cool heat transfer fluid and a heat transfer cooling circuit that cools the lyophilization chamber as well as the condenser. The disclosed heat transfer cooling circuit includes a primary recirculation loop adapted for cooling the lyophilization chamber with the heat transfer fluid, a secondary recirculation loop adapted for cooling a condenser with the heat transfer fluid, and one or more valves operatively coupling the cryogenic heat exchanger system, the primary recirculation loop, and the secondary recirculation loop.