Working Principle and Key Installation Points of Air Release Valves
Add time：2017/12/15 13:50:39 Page views：2849
Air release valves are used for pipeline air venting in independent heating systems, central heating systems, heating boilers, central air‑conditioning systems, floor heating, solar heating systems and other facilities. Water normally contains dissolved air, and the solubility of air decreases as temperature rises. During water circulation, gas gradually separates from water and accumulates to form large bubbles or even air columns. Continuous water make‑up keeps generating gas. Air release valves include air‑conditioning air release valves, solar air release valves, heating radiator air release valves and boiler air release valves.
Working Principle of Air Release Valves
When gas escapes in the system, it rises along the pipeline and finally gathers at the highest point of the system, where air release valves are generally installed. When gas enters the valve cavity and accumulates at the upper part of the air release valve, the internal pressure increases. Once the gas pressure exceeds the system pressure, the water level inside the cavity drops, the float descends accordingly, and the vent opens. After the gas is completely discharged, the water level rises, the float moves upward, and the vent is closed.
Similarly, when negative pressure occurs in the system, the water level in the valve cavity falls and the vent opens. Since the external atmospheric pressure is higher than the system pressure at this moment, atmospheric air flows into the system through the vent to prevent hazards caused by negative pressure. If the bonnet on the valve body is tightened, the air release valve will stop venting. Under normal operating conditions, the bonnet shall be kept open.
Key Installation Points of Air Release Valves
The air release valve must be installed vertically to keep the internal float in vertical position; otherwise, venting performance will be affected.
It is recommended to fit the air release valve together with an isolating valve. This ensures system tightness and prevents water outflow when the air release valve needs to be removed for maintenance.
Air release valves are generally mounted at the highest point of the system to improve venting efficiency.
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