The imaging of shunts in solar cells by infrared lock-in thermography

A valve body adapted for mounting on a fluid pressure operated motor and having inlet and outlet passages for connection to inlet and discharge openings respectively of the motor, the inlet and outlet passages terminating in ports for connection to fluid pressure and return lines respectively. A metering valve element in the outlet passage is operable to vary the flow of fluid from the motor and cause a variation in pressure of fluid in the inlet passage. A shunt valve element in a shunt passage communicating with the inlet passage is operable to cause fluid to bypass the fluid motor in varying quantities.