Abstract: A pilot-operated proportional cartridge valve that has low internal leakage and long life, without requiring close ID/OD spool clearances that add cost to comparable prior art valves. The flow control valve is uniquely characterized by the use of two axially spaced-apart spring energized wiper seals that floatingly support a flow control piston within a cylindrical chamber to allow transaxial shifting movement of the piston for proper alignment with mating components, such as a valve seat. The spring energized wiper seals are preferably oriented in opposite directions for sealing against pressure differentials at opposite ends of the valve piston. In a preferred embodiment, the seals are spring energized cup seals.

Abstract: Provided is a valve having a movable valve member with an orifice, a plunger movable to block/allow flow through the orifice, and a resilient biasing member for resiliently biasing the valve member away from the valve seat. When the plunger is moved to a position allowing flow, fluid flows through the orifice creating a pressure differential in the valve that in combination with the resilient biasing member moves the valve member to a position allowing flow through a main passageway of the valve. During a low or no flow condition, the valve member is held in the position allowing flow to prevent a drop in performance of a system utilizing the valve that would result if the valve member moved to a blocking position.

Abstract: A pilot-operated proportional cartridge valve that has low internal leakage and long life, without requiring close ID/OD spool clearances that add cost to comparable prior art valves. The flow control valve is uniquely characterized by the use of two axially spaced-apart spring energized wiper seals that floatingly support a flow control piston within a cylindrical chamber to allow transaxial shifting movement of the piston for proper alignment with mating components, such as a valve seat. The spring energized wiper seals are preferably oriented in opposite directions for sealing against pressure differentials at opposite ends of the valve piston. In a preferred embodiment, the seals are spring energized cup seals.