Refrigeration apparatus
 Apparatus is described for maintaining refrigerant temperature at or below a predetermined level by providing a combination of a primary chiller cooled by a primary mechanical refrigeration system and a series-connected back-up liquid nitrogen-cooled chiller which would operate only if the primary mechanical refrigeration system is incapable of providing the desired refrigerant temperature. 
Miles Laboratories, Inc.
F F F
F25D F25B F25D
inventional inventional inventional
Steven J.
Toth