The Pressure Reducing Valve is designed to provide a reduced outlet pressure from any given inlet pressure.
Different ways of reducing the pressure
Spring loaded – A force is created from an adjustable spring to act upon a diaphragm or piston to balance a pressure on the downstream side of the valve.
Internally Dome Loaded – Pressurised gas is stored in a dome on one side of a diaphragm or piston to balance downstream fluid pressure on the other side. In this case the dome is loaded by means of a gas bleed from the upstream side of the valve through internally drilled passages and controlled by the operation of needle valves provided for this purpose.
Externally Dome Loaded – Pressurised gas is stored in a dome on one side of a diaphragm or piston to balance downstream fluid pressure on the other side. A tapped thread connection is provided into the dome which may be loaded from any suitable gas source. A convenient feature of this method is that a spring loaded reducing valve may be used as a pilot valve to control dome pressure for ease of adjustment or to provide remote control.
It is recommended that a Wells filter is fitted on the inlet supply to avoid damage to the valve seat from air born debris, especially on new installations – see Wells filters for further info.