Patent ID: 8820097

Claim:
A method for controlling gas temperature in a controlled rate cryogenic chiller or freezing system comprising: providing a plurality of containers in a cooling chamber; providing a material in each of the plurality of containers; providing a source of warm gas; providing a source of liquid cryogen; mixing the warm gas with the liquid cryogen to produce a cryogenic cold gas; and providing a uniform flow of the cryogenic cold gas relative to the plurality of containers in the cooling chamber wherein the flow of the cryogenic cold gas provided to the cooling chamber is substantially unidirectional and along a longitudinal axis of each of the plurality of containers in a manner that prevents recirculation of the cryogenic cold gas within the cooling chamber and wherein heat is transferred between the material in each of the plurality of containers and the cryogenic cold gas; and wherein a temperature of the cryogenic cold gas is adjusted or controlled by regulating a flow rate of the warm gas and a flow rate of the liquid cryogen.