I. Core Functions
Pressure Reduction & Stabilization: Converts fluctuating inlet pressure to a steady preset outlet pressure
Safety Protection: Prevents downstream equipment damage from overpressure
II. Primary Types
| Type | Mechanism | Applications |
|---|---|---|
| Direct-Acting | Spring/diaphragm directly senses outlet pressure | Low-flow, small ΔP (e.g., residential gas) |
| Pilot-Operated | Pilot valve amplifies control force | Industrial high-pressure systems (steam/hydraulics) |
| Ratio-Type | Maintains fixed inlet/outlet pressure ratio | Fire protection water supply |
III. Key Components
Valve Body: Pressure-bearing housing
Disc/Plug: Adjusts flow area for pressure drop
Spring/Diaphragm: Provides actuation force
Pilot Valve (for pilot-operated): Enhances control precision
IV. Operating Principle
Pressure Sensing: Outlet pressure balances against spring preload
Dynamic Adjustment:
↑Outlet pressure → Diaphragm closes valve → ↓Flow → Pressure drops
↓Outlet pressure → Spring opens valve → ↑Flow → Pressure recovers
V. Typical Applications
Industrial: Compressed air systems, steam lines, hydraulic units
Civilian: Gas cooker regulators, water supply pressure control
Special Cases: Oxygen cylinder regulators, fire sprinkler systems
VI. Selection Criteria
Pressure Range: Match valve's max inlet/outlet pressure to system
Flow Capacity: Size orifice based on min/max flow rates
Media Compatibility: Material selection (stainless steel/brass) for gas/liquid/corrosives
Precision Needs: Pilot-operated for tighter control
VII. Troubleshooting & Maintenance
| Symptom | Root Cause | Solution |
|---|---|---|
| Pressure fluctuation | Damaged diaphragm/failed spring | Replace seals/calibrate |
| Leakage | Clogged/worn valve seat | Clean debris/replace components |
| Pilot valve blockage | Contaminants in pilot orifice | Flush system |
VIII. Comparative Analysis
Vs. Safety Valves: PRVs maintain constant pressure; safety valves act as one-time emergency relief
Vs. Throttle Valves: PRVs regulate pressure; throttle valves control flow rate
