Abstract: A refrigerated container is provided which has a refrigeration system and a controlled atmosphere system. The refrigeration system and the controlled atmosphere system are both provided with electronic controllers. The refrigeration controller is programmed with certain acceptable conditions under which the controlled atmosphere system will be allowed to operate. When these conditions are satisfied the refrigeration controller will send an enabling signal to the controlled atmosphere systems controller allowing it to operate. If at any time during operation the refrigeration controller determines that the controlled atmosphere system should not operate, it removes the electrical enabling signal, causing the controlled atmosphere system to stop.

Abstract: A method for controlling operation of a system for controlling the atmosphere within a confined space. The system has an electrical control having a display and electrically controlled components. The components include an air compressor, a filter, an air heater, a separator for dividing air into streams of oxygen and nitrogen, and flow control valves for varying the purity of the nitrogen stream. The system also includes sensors for indicating the temperature leaving the heater and the temperature within the confined space. A sensor indicates the pressure upstream of the control valves. An oxygen sensor and a carbon dioxide sensor are included.

Abstract: Pre-trip operational methods and procedures for automatically checking predetermined functions and the operating performance of a controlled atmosphere system for a refrigerated container. The system includes an electronic control and electrically controlled components including an air compressor, a filter having a drain valve, a heater, a nonelectric membrane separator and two or more flow control valves for varying the purity and the flow from the membrane separator. Various pressure, temperature and safety control devices are provided in the system. The methods include display tests of the indicator lights and display segments on the controller, tests of the drain valves on the filters and of the flow control valves. Tests of the heater and its control and safety mechanisms are carried out. Automatic tests are conducted of the oxygen sensor and CO.sub.2 sensor including span tests and zero point value tests.

Abstract: A refrigeration system control for a refrigerated container unit in which a compressor suction modulating valve is controlled during light loads near its valve seat by rapidly moving the suction modulating valve to an open position away from the valve seat and then moving the suction modulating valve to the desired position.