Fluid pressure regulator establishing a stable output fluid pressure

Abstract

A multi-stage pneumatic pressure regulator establishes a constant output pressure with a change in the output flow. The regulator includes a poppet valve connecting the input and output. A relief valve mounted on the poppet valve includes a first positioning diaphragm subjected to output chamber pressure and a vent hole to atmosphere. A pilot valve is mounted on the relief valve and includes a pressure chamber with a positioning diaphragm of a lesser area than the first diaphragm, coupled to the relief valve and opposing the first position diaphragm. A precision bleed orifice connects the pressure chamber to the input chamber and establishes a precise bleed. A presettable spring load orifice unit in the pilot valve couples the pressure chamber to the output chamber and passes the bleed flow to the output chamber and venting atmosphere. The pilot chamber pressure is greater than the output pressure and prevents feedback of the bleed. The poppet valve and pilot orifice have novel constructions. An alternative bleed passage for a single stage regulator is also disclosed.