, Properties and Uses: The relief valve is a hydraulic pressure control valve. Hydraulic equipment mainly from the constant pressure overflow regulator system unloaded the Netherlands and safety protection role. Constant pressure overflow effects: the quantitative pump throttle adjusting system, a metering pump provided a constant flow. When the system pressure increases, will make traffic demand decreases. The relief valve to open, so that the excess traffic overflow back to the tank to ensure that the relief valve inlet pressure pump outlet pressure constant (valve port often with pressure fluctuations on). The role of regulator: relief valve series the way back to the oil relief valve generates a steady increase of the back pressure moving parts. The small flow solenoid valve system unloading: the remote port class hair cascaded overflow, when the solenoid is energized, the relief valve remote control mouth pass mailbox, then the hydraulic pump unloading. Relief valve unloading valve. Security role: the system work properly, the valve is closed. Only the load exceeds a predetermined limit (the system pressure exceeds the set pressure) to open the overflow, overload protection, so that the system pressure is no longer increased (usually so that the relief valve set pressure higher than the maximum working pressure of the system 10% to 20% ). Practical applications in general: for the unloading valve for remote relief valve, high and low voltage level control valve for the sequence valve, used to generate backpressure (string back to the oil on the road). Relief valves generally have two structures: a direct-acting relief valve. 2, the main requirements of the pilot operated relief valve: voltage range, voltage regulator deviation, runout small pressure sensitive action, overloading capacity, noise.