Refrigeration system for shipping container

Claim 1

A cryogenic refrigeration system, for detachable mounting on a shipping container having a porthole, comprising, (a) a cryogenic refrigerant storage tank, (b) support means including locking assemblies for detachably securing said storage tank to said container externally of the porthole, (c) a porthole cover permanently attached to and carried by said refrigeration system, said cover being positioned relative to said locking assemblies such as to automatically cover the porthole when said refrigeration system is mounted on the shipping container by said locking assemblies, (d) a refrigerant injection tube supported by said porthole cover and positioned at an angle relative to the vertical plane of said cover such as to pass through said porthole and having a length such as to terminate adjacent the upper, internal wall of the shipping container, said injection tube being connected by a refrigerant line to said refrigerant tank, (e) a temperature sensor for sensing the temperature in said container, said temperature sensor being connected to one end of a signal line, (f) a temperature controller connected to the opposite end of said signal line, (g) a refrigerant flow control valve in said refrigerant line intermediate said refrigerant tank and said injection tube, (h) a valve actuator connected to said refrigerant flow control valve, and (i) a signal line connected from said temperature controller to said valve actuator for controlling the flow of cryogenic refrigerant as a function of the temperature sensed in the container by said temperature sensor.