Question

Please Explain Difference between:

-Air Valve

-Pressure Relief Valve

-Air relief Valve

-Air Release Valve

-Pressure Reducing Valve

Answer 1

1. Air valve

• This valve is used to control the flow of air.
• This valve should be large enough to admit and expel large amount of air at low pressure differential.
• It typically uses a float system.
• It can be mainly classified into three types:
  • Air release valve
  • Air/Vacuum valve
  • Combination of air valves

2. Pressure Relief Valve

• This valve is used to relieve pressure (some energy) due to water hammer.
• Water hammer (rapid increase in pressure in a water distribution system) can damage valves.
• During overheating, these valves relieve steam and excess pressure.

3. Air relief Valve

• This valve is used to relieve pressure due to air accumulation at high points in transmission line of the system.
• This valve automatically vents accumulated air at high points.

4. Air Release Valve

• These valves are normally open and it helps to vent air through the orifice.
  • It closes as liquid rises in the system lifting a float within the valve.
• When the operating pressure of the pipeline system is above atmospheric pressure:
  • These valves automatically release small pockets of accumulated air.
• It has outlet orifice smaller than that of inlet
• Valves can be opened under any working pressure up to the maximum if provided with proper float weight.

5. Pressure Reducing Valve

• These valves do not relieve water.
• No discharge pipe is attached to this valve.
• {If an assembly consists of both Pressure Reducing Valve and Pressure Relief Valve, Pressure Relief Valve should be closer to boiler}
• This valve is a backflow preventer valve.