Abstract: Compressors are utilized in an apparatus for treating a product such as tobacco with a liquid cryogen, such as carbon dioxide for removing vapor from a processing chamber and recompressing the vapor to facilitate its return to the cryogen system. When the compressors do not receive a supply of cool vapor from the processing chamber, the compressor temperature rises and the pressure drops. When the pressure reaches a predetermined minimum setpoint, the compressors are interconnected by means of a remotely controlled valve to a vessel containing cryogen vapor at a pressure greater than the pressure at the compressors. A supply of cool cryogen vapor thus flows to the compressors to reduce the temperature, thereby allowing continuous operation of the compressors during periods in which cryogen vapor flow from the processing chamber is interrupted or delayed.