Control system for food transport refrigerator - is designed to avoid overshoot problems and includes two three way valves and time delay

摘要

The control system is for a refrigeration unit with a pressurized liquid gas reservoir. The control system is self-contained and avoids overshoot problems in feeding liquid gas coolant to the container. The system includes a gas line from a liquified gas reservoir, a first gas pressure actuated three-way valve and a second gas pressure actuated three-way valve. A restricting means provides a time delay for switching the second three-way valve from being connected to the gas line to vent. A second restricting means provides a second time delay for switching the second three-way valve from vent to the gas line. A temp. sensing control is also incorporated in another embodiment.