An electro/pneumatic proportional valve.

摘要

An electro/pneumatic proportional valve having a housing (30, 32) defining an upper and lower chamber (36, 38) separated by an annular web (34). An inlet port (42) and exhaust port (56) concentric with the annular web are provided in said lower chamber (38) while an outlet port (40) is provided in the upper chamber (36). An exhaust cylinder (50) is resiliently disposed through the exhaust port (56) and has a radial flange (54) engaging said annular web (34) to occlude the annular webs' central (44) opening. The exhaust cylinder (50) also has an axial bore (52) passing therethrough and existing through the exhaust port (56). A piston (48) disposed in the upper chamber (36) has a pintle (46) which is operative to engage the exhaust cylinder (50) with the displacement of the piston (48) and occlude the exhaust cylinder's axial bore (52). Pilot valves (66, 68) are provided to pressurize the upper chamber (36) in response to a pulse train signal displacing the piston (48) towards the web (34). The displacement of the piston (48) causes the pintle (46) to engage the exhaust cylinder (50) and unseat it from the annular web 34.