Controlled atmosphere system for a refrigerated container

A method of controlling operation of a controlled atmosphere system for controlling the atmosphere within a confined space, the system having an electrical control which has a display, and, electrically controlled components, including, in serial relationship, an air compressor, a filter having a drain valve, an air heater, a nonelectric separator for dividing air into separate streams comprising its principal constituents of oxygen and nitrogen, two or more flow control valves in parallel flow relationship for varying the purity of the nitrogen stream, and including temperature sensors for indicating the temperature leaving the heater and the temperature of the atmosphere within the confined space, a system pressure sensor for providing the pressure upstream of the control valves, the system further including, an oxygen sensor for generating an output indicating oxygen level in a gas, and a carbon dioxide sensor for indicating carbon dioxide level in a gas;

• comprising the steps of:
• energizing the controlled atmosphere system;
• simultaneously operating the electrical control to perform the following steps:
• operating the compressor to an on or off condition responsive to inputs from the oxygen sensor and the carbon dioxide sensor;
• operating the flow control to achieve setpoint oxygen and carbon dioxide levels in the atmosphere, in response to inputs from the oxygen sensor and the carbon dioxide sensor;
• operating a control for the air heater to maintain the output temperature therefrom at a preset value;
• monitoring the oxygen sensor, and, automatically compensating the output when a predetermined atmospheric temperature of the atmosphere is indicated;
• monitoring the carbon dioxide sensor, and, automatically compensating the output when a predetermined change in the temperature of the carbon dioxide sensor occurs;
• monitoring the status of certain system components relative to safety and other operating parameters, and, indicating on the display when said parameters are unsafe or out of an expected range.