SC/BQ series actuators are specially designed for automatic flow regulation of metering pumps. By adjusting the piston stroke of metering pumps, the flow of pumps can follow the change of the proportion of control signals. SC/BQ is a hydraulic damper actuator, which can move more smoothly and the output shaft can withstand the changing load impact. It is composed of double-acting cylinder, pneumatic or electrical positioner, fuel tank and other components. SC/BQ series actuators have the function of self-locking and reserving for gas source failures. It can be equipped with handwheel mechanism and bypass valve to meet manual control in emergency situations.