Pilot pressure reducing valve
The pressure reducing valve can be used to reduce the pressure of one branch to make it lower than the system pressure. Therefore, they can protect downstream components with relatively low pressure.
When the valve is depressurized, the pilot ball will leave the valve seat as the pressure at the regulating port exceeds the valve setting. The pilot fluid causes the pressure of the main valve core to be out of balance, causing the valve core to be lowered to keep the downstream pressure stable. The normally open design allows fluid to enter the pressure reducing port from the inlet with only the pressure drop of the valve itself.
Pressure reducing valve / overflow valve
The pressure reducing valve / overflow valve can be used to reduce the pressure of one branch to make it lower than the system pressure. The valve also acts as an overflow valve to relieve any pressure shock and fluctuation between the pressure reducing port and the actuator. When the valve is in overflow mode, the inlet port is blocked. There are two types of pressure reducing valves / relief valves on the market: pilot type and direct acting type. Direct acting type is usually used in static applications, either response is the key factor or leakage is very important.
Pilot type
When the valve is depressurized, the pilot ball will leave the valve seat as the pressure at the regulating port exceeds the valve setting. The pilot fluid causes the pressure of the main valve core to be out of balance, causing the valve core to be lowered to keep the downstream pressure stable. The pressure impact and fluctuation of the regulating port further moves the valve core and releases the fluid to the oil tank.
Direct acting
If the pressure at the regulating port exceeds the valve setting, the valve will decrease or close to keep the downstream pressure stable. The pressure impact and fluctuation of the regulating port further moves the valve core and releases the fluid to the oil tank. This valve is not used for fluid with rapidly changing pressure, which may lead to unstable conditions.