Patent ID: 7731152

Claim:
A valve actuator assembly, comprising: an actuator housing; a piston disposed within the actuator housing, the piston configured to couple to a valve element and including an inner cylindrical section and an outer cylindrical section, the outer cylindrical section spaced apart from the inner cylindrical section to define a recess, the piston further configured to move within the actuator housing in a first direction and a second direction, to thereby move the valve element toward an open position and a closed position, respectively, the piston including a first side at least partially defining a pressurized closing chamber and a second side at least partially defining a pressurized opening chamber; a regulator coupled between the pressurized closing chamber and the pressurized opening chamber and configured to regulate pressure in the pressurized opening chamber by bleeding off air; a dynamic seal in series with the regulator and disposed between the pressurized closing chamber and the actuator housing; and a spring disposed within the actuator housing and configured to supply a bias force that urges the piston to move in the first direction, the spring at least partially disposed within the recess and at least partially surrounding the inner cylindrical section.