air pressure regulator ball valves gas regulator AIR PRESSURE REGULATOR Principles of operation for the Model 5200P air pressure regulator: Turning the adjusting screw changes the force exerted by the range spring on the diaphragm assembly. In equilibrium of set air pressure, the force exerted by the range spring is balanced by the force form the output air pressure acting underneath the diaphragm assembly. An unbalanced state between the output pressure and the set pressure causes a corresponding reaction in the diaphragm and supply valve assemblies. If the output in the air pressure regulator rises above the set pressure, an upward force is exerted on the diaphragm assembly causing the relief seat to lift and open. Excess pressure in the air pressure regulator is vented to atmosphere until equilibrium is reached. If the output pressure drops below the set pressure the unbalance force of the range spring causes a downward force on the diaphragm as sem bly. The supply valve then opens until the pressure builds up once more to the equilibrium condition. Under forward flow conditions, the range spring force is balanced by the diaphragm pressure force, with the supply valve open just enough to maintain the required equilibrium pressure. When high flow occurs, a specially designed aspirator helps maintain downstream pressure and compensates for droop.