Patent ID: 7739914

Claim:
A fluid control assembly for controlling flow of a working fluid through a valve testing apparatus employing a fluid supply and a motor operated by flow of the working fluid, the fluid control assembly comprising: an operation valve for fluid connection to the fluid supply to selectively control movement of the working fluid from the fluid supply to the motor; an adjustable pressure-responsive valve having an inlet connected to the operation valve to permit fluid communication with the operation valve to receive flow of the working fluid from the operation valve, the pressure-responsive valve having an outlet, the pressure-responsive valve having a normal condition in which working fluid entering the inlet of the pressure-responsive valve substantially completely flows to the outlet of the pressure-responsive valve and a diverting condition in which at least a portion of the flow of the working fluid into the inlet of the pressure-responsive valve is diverted to a bypass outlet of the pressure-responsive valve, the pressure-responsive valve changing from the normal condition to the diverting condition when the pressure-responsive valve senses that a pressure of the flow of the working fluid entering the inlet of the pressure-responsive valve substantially equals or exceeds a threshold pressure, the pressure-responsive valve being manually adjustable to set the threshold pressure; a preload valve having an inlet connected to the outlet of the pressure-responsive valve to permit fluid communication between the outlet of the pressure-responsive valve and the inlet of the preload valve, the preload valve having an outlet for connection to the motor of the valve testing apparatus, the preload valve having an open condition in which flow of the working fluid through the preload valve is not blocked and a closed condition in which flow of the working fluid through the preload valve is substantially blocked such that the pressure-responsive valve is exposed to a maximum pressure generated by the fluid supply without allowing flow through the motor.