Edmund J. Copeland and unidentified man examining refrigeration unit

View of Edmund J. Copeland and an unidentified man examining an electric automatic refrigeration unit. Label on back: "Public Relations Department. Kelvinator Division, American Motors Corporation, Detroit 32, Michigan. 18583. Inventor of electric automatic thermostat that made electric automatic refrigeration possible explains operation to author. On top of the evaporator (cooling unit) to the left is the expansion valve. It is this device that controls the pressure of the refrigerant in the cooling coils. It is adjustable to provide different degrees of temperature. The coil to the right is controlled by temperature. The last cooling effect of the refrigerant takes place in this thermo-coil, causing the thermostat to cut out. Also, the thermo-coil is the first element to warm up during the idle period, causing the thermostat to cut in. Whiles there is an extreme temperature range of about 12 degrees in the coil to cause the thermostat to act, it held the temperature inside the box within a range of 1-1/2 to 2 degrees, so accurate is it. The thermostat also is adjustable, thus providing various ranges of temperature. The coil on the under side of the thermostat is a sylphon bellows. Sylphon, by the way, is a trade name for a well known copper bellows. In it is sulphur dioxide. When heated the sulphur dioxide expands, throwing the switch in contact, and starting the motor. As the temperature falls the pressue of this coil spring pushes the sylphon down, breaking the circuit. By reason of cooling, the pressure of the sulphur dioxide in the sylphon is reduced, permitting the coil to expand and shut off the current. Note the prophetic vision of the early makers of this cooling unit with the tray for freezing ice cubes which years later were to prove a most popular feature in the sale of electric refrigerators. (This caption material was with original picture owned by E.J. Copeland; Heath-Jipson copied for Kelvinator Division, January, 1954)." Handwritten on back: "Copeland, Edmund J."