Constant Pressure Expansion Valves

The PDA-1-0/80 constant pressure or automatic expansion valve is a downstream pressure regulating device that is applicable on ammonia (R-717) systems. The valve regulates the mass flow rate of refrigerant to maintain downstream pressure at a constant value. The normal application of this valve is to feed liquid refrigerant to an evaporator with a relatively constant heat load. However, the PDA-1-0/80 can be used to maintain a constant downstream pressure on other applications as well.