Patent ID: 6595240
Filing Date: 2003-07-22
Classification: F16K,Y10T

Abstract:
A three-way plastic diaphragm valve with creep compensation comprising:a plastic valve body having a first flow duct, a second flow duct, a common flow duct, a first valve seat positioned between the first flow duct and the common flow duct, and a second valve seat positioned between the second flow duct and the common flow duct, a valve stem assembly comprising a first valve member, a first diaphragm, a second valve member, a second diaphragm, an resiliently extensible portion configured as a bellows, the first valve member, the first diaphragm, the second valve member, the second diaphragm, and the extensible portion all integral with one another, the first valve member movable into and out of a sealing position with the first valve seat for controlling flow between the first flow duct and the common flow duct and the second valve member portion movable into and out of a sealing position with the second valve seat for controlling flow between the second flow duct and the common flow duct, the extensible portion positioned between the first valve member portion and the second valve member portion allowing movement of one of the first valve member portion and the second valve member portion without movement of the other; a first captured spring mechanism operatively engaged with the first valve member portion; a second captured spring mechanism operatively engaged with the second valve member portion; and an actuation portion engaged with the first valve member through the first captured spring mechanism and engaged with the second valve member to move the first valve member portion into the sealing position with the first valve seat, and simultaneously compressing the second captured valve spring mechanism thereby moving the second valve member out of the sealing position with the second valve seat.