Pressure Reducing Valve is a type of pressure control valve, used to reduce the pressure at particular locations of the system. It is generally used in the hydraulic systems where the low pressures are required. This valve is actuated by down stream or outlet pressure, and is closed when this pressure reaches the valve setting pressure.
Construction of Pressure Reducing Valve
The schematic diagram of pressure reducing valve is shown below Figure 1.
Fig. 1: Pressure Reducing Valve
It is a normally opened pressure valve consisting of an adjustable spring and a movable spool. The adjustable screw is used to set the spring force equal to the pressure required in the system. A movable spool is used to control the pressure of downstream. Inlet and outlet ports are provided to allow the fluid to flow from pressure line to the system. A drain line is provided at the spring chamber in order to return the fluid leaked past the spool into the tank. Down-stream pressure signals are transmitted to the spool by the control signal line arranged inside the valve as shown in Figure 1.
Working of Pressure Reducing Valve
When the pressure iii the system is less than the preset value of spring force, free flow of fluid takes place from the inlet port to the outlet port without any restriction. If the downstream pressure reaches to time preset value, timen the control signal line transmits the output pressure to time spool. Then, spool moves upwards against the spring force amid closes the outlet port partially. Due to this, flow rate of fluid gets reduced, thereby by the downstream pressure will decrease to a value below the valve setting. If the spring is completely closed, time fluid leaks into spring chamber past the spool and then drained to downstream, which leads to raise in pressure of downstream above preset valve. Thus, it is avoided, as time fluid is drained continuously to time tank.
Advantages of Pressure Reducing Valve
- It provides stable fluid pressure in the system.
- By attaching a check valve, it allows free flow in the reverse direction.
- Throttling noise is less.
- Less maintenance.
Applications of Pressure Reducing Valve
- It is used in electrical water heaters and isolated appliances such as washing machines, etc.
- Used in industrial and commercial plants.
- Used in domestic applications.
- Used in marine applications.
- Used in compressed air plants.
- Sprinkle equipment, etc.