Patent ID: 7249748

Claim:
An electric motor actuated stop and self-closing check valve for controlling forward 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 free to move along the longitudinal axis of said valve stem to either: i) a closed position whereat the valve disc sealingly engages the valve seat to prevent forward and back-flow of the liquid, or ii) an open position whereat the valve disc is spaced from the valve seat, D) an electric motor operationally attached to said valve body, E) an actuator rod moveable by action of the electric motor to be disposed at either: i) an extended position whereat the actuator rod contacts the valve stem and restrains the valve disc at the closed position preventing forward and back-flow of the liquid, or ii) a retracted position whereat the actuator rod is retracted and the valve disc is free to move along the longitudinal axis of the valve stem, without 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 momentary back-flowing liquid on the valve disc and said liquid back-flow is prevented, and F) a hydraulically operated valve disc closing-speed regulator operatively attached to the valve to control the closing speed of the valve disc, wherein said closing-speed regulator comprises: i) a cylinder operatively attached to the valve body, ii) a piston operatively attached to the disc stem for movement within said cylinder along its longitudinal axis, and iii) a hydraulic oil reservoir with connecting piping to the cylinder, said connecting piping having a check/needle valve.