Patent ID: 8057192

Claim:
A condensate pump, comprising: a condensate reservoir having a fluid inlet, an inlet check valve operable to prevent a flow of fluid out of the condensate reservoir through the fluid inlet and to allow a flow of fluid into the condensate reservoir through the fluid inlet, a fluid outlet, and an outlet check valve operable to prevent a flow of fluid into the condensate reservoir through the fluid outlet and to allow a flow of fluid out of the condensate reservoir through the fluid outlet; a liquid level sensor operable to sense a liquid level within the condensate reservoir; and a pressure/vent valve further comprising a primary piston slidably supported in a primary cylinder, wherein the primary piston slides in the primary cylinder responsive to the liquid level sensor, between a first primary piston position and a second primary piston position, the primary piston further including a vertical aperture extending from a first end of the piston to an opposite end of the piston, the opposite end in fluid communication with the condensate reservoir; a pressure source, a pressure vent, a three-way valve further comprising a secondary piston slidably supported in a secondary cylinder, wherein the secondary piston slides in the secondary cylinder between a first secondary piston position in which the pressure source is in communication with a gas space of the condensate reservoir and the pressure vent is isolated from the gas space, and a second secondary piston position in which the pressure source is isolated from the gas space and the pressure vent is in communication with the gas space, and wherein the movement of the secondary piston in the secondary cylinder is responsive to movement of the primary piston in the primary cylinder.