Patent ID: 8181931
Filing Date: 2012-05-22
Classification: E21B,F16K

Abstract:
1. A valve actuator for actuating a valve between an open and a closed position, the valve actuator comprising: a housing: a main piston for coupling to the valve and axially movable within a bore of the housing, so that moving the piston to a first location in the bore configures the valve in an open position and moving the piston to a second location in the bore configures the valve in a closed position; a rotatable camplate having a contoured surface; a piston assembly reciprocatable within a cylinder in the housing fillable with fluid, the piston assembly engagable with the contoured surface, so that rotating the camplate reciprocates the piston assembly within the cylinder; a hydraulic fluid cylinder discharge in the cylinder, so that moving the piston assembly in one direction pushes the fluid into the cylinder discharge; and a hydraulic circuit in fluid communication with the cylinder discharge and in selective communication with the bore on opposing sides of the main piston, so that selectively directing hydraulic flow to a side of the main piston moves the main piston between the first and second locations in the bore.