Patent ID: 8733387

Claim:
A portable valve that has: a main valve body that has an inlet to and an outlet from a central chamber; a piston that is mounted for axial movement within the central chamber between an open position and a closed position; a seating surface on the piston that seats against part of the valve when the piston is in the closed position and moves away from that part of the valve when the piston moves to the open position, opening a flow channel between the inlet and the outlet when the piston is in the open position and closing that flow channel when the piston is in the closed position; a peripheral wall on the piston that has an outer surface that forms a boundary of the flow channel when the piston is in the open position, and an inner surface that faces radially inwardly; a pressure chamber that is bounded by the inner surface on the peripheral wall on the piston and a lateral surface that is fixed in position within the valve body; a pilot channel of fixed shape along its entire fluid length that extends from an upstream side of the flow channel to the pressure chamber; a pilot valve that selectively opens and closes the pilot channel, putting the upstream side of the flow channel in fluid communication with the pressure chamber when the pilot valve is open, and blocking such communication when the pilot valve is closed; and a remote controller that enables an operator to selectively control the pilot valve from a distance.