Pressure Reducing Valve
A Pressure Reducing Valve is a self‑acting mechanical valve that automatically reduces and stabilizes inlet pressure to a constant,safe outlet pressure,protecting downstream equipment and ensuring stable system operation. Core Working Pri...
A Pressure Reducing Valve is a self‑acting mechanical valve that automatically reduces and stabilizes inlet pressure to a constant,safe outlet pressure,protecting downstream equipment and ensuring stable system operation.
Core Working Principle
PRVs operate on a force‑balance feedback loop using the medium’s own energy(no external power required):
1.Setpoint Force:A pre‑adjusted spring provides the target pressure force.
2.Sensing:A diaphragm or piston senses downstream pressure and converts it to mechanical force.
3.Actuation:
-If downstream pressure<setpoint:Spring force opens the valve→increased flow→pressure rises.
-If downstream pressure>setpoint:Sensed force closes the valve→reduced flow→pressure drops.
4.Stabilization:The valve modulates continuously to balance forces,maintaining outlet pressure within a narrow tolerance.
Main Types&Characteristics
1.Direct‑Acting PRV
Structure:Spring+diaphragm/piston directly controls the main valve.
Principle:Downstream pressure acts directly against the spring to adjust opening.
Pros:Simple,compact,fast response,low cost,no minimum inlet pressure required.
Cons:Lower accuracy,limited flow capacity.
Applications:Low‑pressure,small‑flow systems(e.g.,gas appliances,small air lines,residential water).
2.Pilot‑Operated PRV(Indirect‑Acting)
Structure:A small pilot valve senses pressure and controls the main valve via fluid pressure.
Principle:Pilot valve amplifies pressure signals to drive the main valve,enabling high precision and large flow.
Pros:High accuracy,large flow capacity,stable under wide pressure/load swings.
Cons:More complex,requires minimum inlet pressure to operate.
Applications:Industrial pipelines,steam systems,high‑rise building water supply,process plants.
3.By Sensing Element
-Diaphragm Type:High sensitivity,good for gases/clean liquids;limited pressure rating.
-Piston Type:High pressure resistance,durable;suitable for steam,oil,heavy‑duty fluids.
-Bellows Type:Excellent sealing,corrosion resistance;used for corrosive or toxic media.
