Pressure compensated priority flow control valve.

• Pressure-compensated flow control valves are designed to provide a constant volume flow rate independent of the pressure drop across the valve. By contrast, non-pressure-compensated valves have a variable flow rate that changes if the pressure drop across the valve fluctuates. 

• Pressure-compensated flow control valves are useful in a variety of hydraulic applications. For example, they benefit situations where it is necessary to maintain a constant speed of operation of a hydraulic cylinder regardless of the magnitude of the load that the cylinder is moving. This is because the speed of a hydraulic cylinder is proportional to the volume flow rate of hydraulic fluid it receives. 
• Pressure compensated flow control valves are also useful in maintaining constant rpm of a hydraulic motor independent of load on the motor. Much like the example above, changing loads on the motor will result in a fluctuating pressure drop across the valve ahead of the motor. Pressure-compensated flow control valves compensate for these fluctuations to provide a steady flow rate to the hydraulic motor, maintaining its rpm at a constant rate.