Pressure control valve for railway vehicles

摘要

A railway car pressure control valve having an adjustable middle body member. An air supply chamber connected to a source of compressed air and an output chamber connected to an output passage. An exhaust chamber opened to the atmosphere. An air supply valve spring biased toward a valve seat. A hollow exhaust valve rod having a valve tip located adjacent the air supply valve. A control piston including a control piston diaphragm is attached to the inside wall of the main valve body. A balance piston including a balance piston diaphragm attached to the inside wall of the main valve body. A plurality of first and second radially extending fins carried by the balance piston and the inside wall of the main valve body, respectively. A protective member interposed between the balance piston diaphragm and the radially extending fins to prevent wave distortion of the balance piston diaphragm and preclude increase resistance to movement of the main piston.