Patent ID: 6186471
Filing Date: 2001-02-13
Classification: F16K,Y10T

Abstract:
An electrically-operated actuator for actuating a valve in a heating or cooling flow system, the actuator being normally supplied with electrical power from a main source of electrical power, the valve having a first position in which fluid flow may occur along one path and a second position in which fluid flow is either blocked or may occur along a second path, at least one of the positions being a fail safe position to which the valve should return in the event of loss of electrical power from the main electrical power source, the actuator comprisinga motor coupled to the valve, wherein rotation of the motor changes the position of the valve from one of the first and second positions to the other of the positions;a switch controlling the delivery of electrical power to the motor, the switch having a closed position in which electrical power is delivered to the motor and an open position in which power is not delivered;one or more sensors configured to detect the arrival of the valve at the first and second positions;an electrical power storage element providing power for driving the motor; andcircuitry connected to the one or more sensors and to the switch, the circuitry being configured to respond to the detection by the one or more sensors of the arrival of the valve at one of the first and second positions by opening the switch to stop delivery of power to the motor, andthe circuitry being further configured so that in the event of loss of electrical power from the main electrical power source, electrical power from the electrical power storage element is used to return the valve to the fail safe position, by powering the motor until the one or more sensors detects arrival of the valve at the fail safe position, at which time the switch is opened to stop delivery of power to the motor, to leave the valve in the fail safe position, andwherein the valve is returned to the fail safe position and stopped at the fail safe position without use of a mechanical stop.