Patent ID: 6929238

Claim:
An electric motor actuated stop and self-closing check valve for controlling forward-flow and back-flow of liquid in a liquid conveying line and reducing liquid surge pressure transients and slamming of valve components, comprising: A) a valve body having an inlet port and an outlet port, relative to forward-flow of a liquid, B) a valve seat disposed within the valve body intermediate said ports, C) a valve disc disposed within the valve body having an elongated disc stem which extends through the valve body, said valve disc and disc stem being moveable along the longitudinal axis of said disc stem to either: i) a closed position whereat the valve disc sealingly engages the valve seat to prevent forward-flow and back-flow of the liquid, or ii) an open position whereat the valve disc is spaced from the valve seat, D) a compression spring external to said valve body for providing a selected bias to said valve disc and disc stem toward said closed position; E) an electric motor operationally attached to said valve, and F) an actuator rod moveable by action of the electric motor such that said actuator rod is disposed at either: i) an extended position of said actuator rod whereat the actuator rod contacts the disc stem and restrains the valve disc at the closed position preventing forward-flow and back-flow of the liquid, or ii) a retracted position of said actuator rod whereat the actuator rod is retracted any amount from said extended position to be at a selectable retracted position, and at all selectable retracted positions of said actuator rod the valve disc is moveable along the longitudinal axis of the disc stem, without further action by the electric motor, such that: a) the valve disc moves to the open position solely through action of forward flowing liquid on the valve disc and forward-flow of the liquid occurs, and b) the valve disc moves to the closed position through action of said compression spring and momentary back-flowing liquid on the valve disc and said liquid back-flow is prevented.