Abstract: A control for use with an expendable refrigeration system is disclosed which has particular use in refrigerated transport applications. The control is used to regulate the injection of refrigerant into the space to be refrigerated and provides an accurate means of precisely selecting a preferred ratio of "on" to "off" timing segments in each cycle and the number of complete cycles in a given time frame. In one embodiment of the invention, pneumatic pressures are used to power an oscillating device, the number of oscillations are counted to a selectable total. Attainment of the chosen total causes the counter to transmit a signal, which signal actuates the operator of a four-way valve. The switching of the valve provides the means to (a) open a liquid line valve to inject the refrigerant into the refrigerated space and (b) reset the counter, terminate the actuation signal and start the next cycle count.

Abstract: A self contained refrigerated shipping or storage container utilizing liquid carbon dioxide is disclosed. The container utilizes a network of liquid containing units arranged to allow maximum useful storage space with maximum cooling. The container is insulated and has four walls, at least one of which has at least one access door therein, a floor and a roof, with a pressurized liquid carbon dioxide reservoir having a workable heat exchange relationship with the interior of the container. The reservoir includes a gaseous space with a vent from the space having a pressure relief valve therein adapted to maintain a substantially constant pressure in the reservoir such that the temperature of the liquid carbon dioxide in the reservoir is controlled.

Abstract: An expendable refrigeration system is disclosed for use with an insulated storage compartment. The system utilizes a concept of the liquid coolant storage reservoir being kept at a cold temperature and withdrawing heat from a storage compartment. The pressurized uninsulated liquid carbon dioxide storage reservoir is within the storage compartment and has a vent from a gaseous space in the liquid storage reservoir. A pressure relief valve is installed in the vent adapted to maintain a substantially constant pressure within the liquid storage reservoir, such that the temperature of the liquid carbon dioxide within the storage reservoir is controlled and is below the desired temperature within the insulated storage compartment.

Abstract: A control system for a refrigeration unit incorporating a pressurized liquid gas reservoir is disclosed. The control system is self-contained and suitable for use in the transportation of food in containers. The improvement of the present system is that it 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, a second gas pressure three-way valve, a first restricting means which provides a time delay for switching the second three-way valve from being connected to the gas line to vent and a second restricting means which provides a second time delay for switching the second three-way valve from vent to the gas line. A temperature sensing control is also incorporated in another embodiment of the invention.