Abstract: A variable fluidic time delay system for operating a plurality of pressure sensitive control switches to effect sequential operations at different pressure settings or for different components in response to the fluid pressure at a predetermined location in a refrigeration system, the time delay system including a fluid flow restrictor and unidirectional flow control in parallel by-pass relation with each other and connecting the control switches to the predetermined location of the refrigeration system for restricting pressurized fluid flow with a concomitant time delay in one direction and providing unrestricted fluid pressure equalization in the other direction, respectively.

Abstract: A refrigeration system including multiple parallel compressors for maintaining evaporator suction pressures within preselected ranges, said compressors being sequentially and cyclically operative through control switch means responsive to preselected upper and lower refrigerant suction pressures, a fluidic time delay system for operating the pressure responsive switch means comprising restrictor means interposed between the common suction header for the compressors and the pressure responsive switch means therefor to restrict refrigerant fluid flow to the pressure switches upon increases in suction header pressure, and unidirectional flow means for providing unrestricted reduction of the pressure acting on the switch means upon relative decreases in suction header pressure.