Patent ID: 9587873
Date: 2017-03-07
CPC Classifications: A01N,A61L,F25B,F25D,G01N

Claim:
1. An ultra-low temperature freezer for operating at a temperature below −50 degrees C. and having an enclosed cabinet including a surrounding wall of thermal foam insulation having an interior side and an exterior side and a refrigerating apparatus, the freezer comprising: (a) a thermosiphon connected to the refrigerating apparatus and containing a two phase refrigerant, the thermosiphon comprising a tube wound in turns along the interior side of the thermal foam insulation; (b) a plurality of rotatable trays within the cabinet and inwardly of the thermosiphon for supporting contents stored in the freezer; (c) one or more cavities formed in and surrounded by the thermal foam insulation, the cavities being located exteriorly of the thermosiphon and interiorly of the exterior side of the thermal foam insulation at a location where the temperature is warmer than within the freezer and having a temperature gradient across the cavities; and (d) a plurality of tray drives, each drive including a controlled position motor mounted in one of said one or more cavities, each motor being drivingly linked to a rotatable tray for driving the tray in rotation to a selected angular displacement.