Abstract: A three-way valve includes a rotatable shaft positioned within a cylindrical, linear bore within a housing. A fluid pressure source is coupled via an input port to an inner end of the bore which includes a valve chamber. An output port coupled to a pressure-operated device is also disposed in the housing and is connected to the valve chamber, as is a drain port. Attached to the shaft's inner end is a first seal, while a second seal is attached to the shaft in closely spaced relation to the first seal. Rotational displacement of the shaft clockwise causes the first seal to seal off the source of fluid pressure from the valve chamber, while allowing for fluid discharge through the drain port. Rotational displacement of the shaft in a second, opposed direction connects the pressure-operated device to the pressure source via valve chamber and isolates valve chamber from drain port.

Abstract: A three-way valve includes a rotatable shaft positioned within a cylindrical, linear bore within a housing. A fluid pressure source is coupled via an input port to an inner end of the bore which includes a valve chamber. An output port coupled to a pressure-operated device is also disposed in the housing and is connected to the valve chamber, as is a drain port. Attached to the shaft's inner end is a first seal, while a second seal is attached to the shaft in closely spaced relation to the first seal. Rotational displacement of the shaft clockwise causes the first seal to seal off the source of fluid pressure from the valve chamber, while allowing for fluid discharge through the drain port. Rotational displacement of the shaft in a second, opposed direction connects the pressure-operated device to the pressure source via valve chamber and isolates valve chamber from drain port.