Patent ID: 8474301

Claim:
A shut-off valve testing system, comprising: a hydraulic control cylinder having an actuator volume, a return volume, and a piston therebetween; a differential pressure transmitter communicating with the actuator and return volumes of the hydraulic control cylinder; a hydraulic actuator selectively communicating hydraulically with the actuator volume of the control cylinder, the hydraulic actuator having a loading pressure volume, an actuating pressure volume, and a piston therebetween, the hydraulic actuator further communicating with and controlling a main shut-off valve; a first hydraulic valve disposed between the actuator volume of the control cylinder and the hydraulic actuator; a source of hydraulic pressure communicating with the return volume of the control cylinder; a second hydraulic valve disposed between the source of hydraulic pressure and the return volume of the control cylinder; a source of hydraulic pressure communicating with the loading pressure volume and the actuating pressure volume of the hydraulic actuator; a third hydraulic valve disposed between the source of hydraulic pressure and the actuating pressure volume of the hydraulic actuator; a hydraulic reservoir communicating with the actuating pressure volume of the hydraulic actuator; a fourth hydraulic valve disposed between the source of hydraulic pressure and the hydraulic reservoir; and a fifth hydraulic valve disposed between the actuating pressure volume of the hydraulic actuator and the hydraulic reservoir.