Proportional flow valve with diaphragm pressure member

摘要

A proportional flow valve wherein inlet fluid pressure urges a main valve unit having a main valve member and a surrounding diaphragm toward the valve seat. The diaphragm is connected to the valve body and has a bleed passageway to enable inlet fluid to pass from an inlet port below the main valve unit to a reservoir above it. The area of the main valve unit exposed to the reservoir is substantially greater than the area of the main valve unit exposed to the inlet port. A solenoid actuator determines the position of a pilot valve sealing member which controls the flow of inlet fluid from the reservoir through a pilot opening in the main valve member to an outlet port to selectively relieve the pressure above the main valve unit thereby permitting the main valve unit to move away from the main valve seat.