Understanding the Basics of Gas Pressure Reducing Valves/Regulators？

I. Core Functions

1. Pressure Reduction and Stabilization
   • Reduce high-pressure gas from upstream (e.g., municipal medium-pressure pipe networks) to low pressure suitable for equipment (e.g., household gas stoves require 2000Pa) and maintain stable outlet pressure.
2. Safety Protection
   • Automatically adjust valve opening when upstream pressure is abnormal or downstream gas consumption changes suddenly, preventing explosions caused by excessive pressure or flameout due to insufficient pressure.
3. Flow Control
   • Dynamically adjust the flow area according to gas consumption to ensure continuous gas supply.

II. Working Principle (Taking Direct-Type Regulators as an Example)

• Sensing Elements (Diaphragm/Spring): Detect changes in outlet pressure and convert them into mechanical displacement.
• Regulating Elements (Valve Core/Seat): Adjust valve opening based on displacement to control gas flow.
• Feedback Mechanism: Achieve automatic regulation through the dynamic balance between outlet pressure and spring preload.

• Outlet Pressure Decreases (e.g., Increased Gas Consumption):
  • Reduced pressure below the diaphragm causes the spring to push the diaphragm downward → valve core opens → gas flow increases → outlet pressure rebounds to the set value.
• Outlet Pressure Increases (e.g., Decreased Gas Consumption):
  • Increased pressure below the diaphragm compresses the spring upward → valve core closes slightly → gas flow decreases → outlet pressure drops to the set value.

III. Main Classifications

By Structure and Working Mode

1. Direct-Type Regulators
   • Driving Method: Regulated by the balance between the gas’s own pressure and spring force, requiring no external energy.
   • Characteristics: Simple structure, fast response, but adjustment accuracy is affected by inlet pressure fluctuations. Suitable for small-to-medium flow scenarios (e.g., household use, small commercial settings).
   • Typical Models: Household pressure reducing valves (e.g., JYT-0.6), building-level regulators (e.g., RTZ-*).
2. Indirect-Type Regulators
   • Driving Method: Signals are amplified by a pilot (small regulator) to control the main valve, requiring external energy (e.g., pilot tube gas).
   • Characteristics: High adjustment accuracy and large output flow, suitable for high-pressure or large-flow scenarios (e.g., gate stations, industrial pipe networks).
   • Typical Models: T-type regulators (combination of main valve and pilot).

By Purpose and Pressure Class

IV. Key Technical Parameters

1. Inlet Pressure (P1) and Outlet Pressure (P2)
   • Must match upstream and downstream pipeline pressures. Outlet pressure can be manually set via spring preload (e.g., clockwise rotation of household pressure reducing valves increases pressure).
2. Maximum Flow (Qmax) and Minimum Flow (Qmin)
   • The regulator’s flow must cover actual gas consumption during selection (e.g., household gas consumption is approximately 2–4 m³/h, requiring a pressure reducing valve with Qmax ≥6 m³/h).
3. Pressure Regulation Accuracy
   • Direct-type regulators typically have an accuracy of ±10%, while indirect-type regulators can achieve within ±5%.
4. Closing Pressure (Pb)
   • The maximum outlet pressure when the downstream valve is closed, which must be ≤1.2 times the set pressure (ensuring safety).

V. Selection Criteria

1. Clarify Operating Conditions
   • Pressure Class: Select corresponding models based on upstream pipeline pressure (e.g., medium-pressure regulators for municipal medium-pressure pipe networks).
   • Flow Range: Choose 1.2–1.5 times the maximum gas consumption to avoid unstable pressure due to "overloading."
   • Installation Method: Threaded connections (household) or flange connections (industrial).
2. Safety Performance
   • Explosion-proof regulators must be selected for gas environments, with overpressure shut-off functions (e.g., combined regulators with shut-off valves).
3. Environmental Adaptability
   • For outdoor installation, select models with a protection level of IP54 or higher. In cold regions, anti-icing designs (e.g., electric tracing) are required.

VI. Installation and Maintenance Considerations

Installation Requirements

1. Correct Direction: The arrow on the valve body must align with the gas flow direction; reverse installation is prohibited.
2. Straight Pipe Sections: Maintain 5–10 times the pipe diameter of straight pipe upstream and 3–5 times downstream to ensure stable gas flow.
3. Bypass and Safety Devices: Industrial scenarios require bypass pipelines (for maintenance) and safety valves (to prevent overpressure).

Daily Maintenance

1. Regular Inspections:
   • Check joint airtightness with soapy water;  is prohibited.
   • Monitor pressure gauges to ensure outlet pressure remains within the set range.
2. Cleaning and Maintenance:
   • Remove dust from the valve body to prevent debris from blocking the valve port (especially the diaphragm chamber of direct-type regulators, which is prone to dust accumulation).
   • Perform professional maintenance at least once a year to inspect spring elasticity and valve core wear.
3. Troubleshooting:
   • Large outlet pressure fluctuations: May be due to spring fatigue or diaphragm damage; replace components.
   • Unusual noise or vibration: May be due to high gas flow velocity or unstable installation; adjust installation or add vibration-damping measures.

VII. Common Issues and Solutions

VIII. Safety Codes and Standards

• Domestic Standards:
  • GB 50028-2020 Code for Design of City Gas Engineering: Specifies requirements for regulator installation locations and pressure classes.
  • CJ/T 5054-2016 Household Gas Regulators: Standardizes technical indicators for household pressure reducing valves.
• Operation Prohibitions:
  • Unauthorized disassembly or modification of regulators is prohibited (may cause gas leaks or pressure loss).
  • Do not stack flammable materials around regulators or block equipment; ensure good ventilation.

Conclusion