摘要 |
A motor-driven piston-type valve including a valve body having a horizontally disposed fluid flow passageway. A valve piston is operatively mounted in the body for vertical movement therein to selectively close and open the passageway. An electric motor is operatively connected to the piston to vertically move the same. A slip clutch is operatively interposed between the motor and the piston whereby clutch slippage is effected when the piston encounters a predetermined resistance in its vertical movement. A limit switch is operatively connected to the clutch for triggering by clutch slippage, such limit switch also being electrically connected to the motor, whereby when the piston encounters a predetermined resistance in its vertical movement, resultant clutch slippage triggers the limit switch to stop the motor.
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