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What’s Exhaust Valve?

Views: 97     Author: Site Editor     Publish Time: 2020-03-17      Origin: Site

What’s Exhaust Valve?

Exhaust valves are used for exhausting pipes such as independent heating systems, central heating systems, heating boilers, central air conditioners, floor heating and solar heating systems.


When gas escapes from the system, the gas will climb up the pipeline and eventually gather at the highest point of the system. The exhaust valve is generally installed at the highest point of the system. When the gas enters the valve cavity of the exhaust valve and gathers at the upper part of the exhaust valve, the pressure increases with the increase of the gas in the valve. When the gas pressure is greater than the system pressure, the gas will cause water level in the chamber drops, and the pontoon drops with the water level, opening the exhaust port. After the gas is exhausted, the water level rises, and the buoy also rises, closing the exhaust port. For the same reason, when negative pressure is generated in the system, the water surface in the valve cavity drops and the exhaust port opens. At this time, the external atmospheric pressure is greater than the system pressure, so the atmosphere will enter the system through the exhaust port to prevent the harm of negative pressure. If the valve cap on the valve body of the exhaust valve is tightened, the exhaust valve stops exhausting. Generally, the valve cap should be open. The exhaust valve can also be used in conjunction with the isolation valve to facilitate the maintenance of the exhaust valve.


1. The float of the exhaust valve uses low-density PPR and composite materials. This material will not deform even if it is immersed in high temperature water for a long time.

2. The pontoon lever is made of hard plastic, and the connection between the lever and the pontoon and the support is movable, so it will not cause rust during long-term operation.

3. The sealed end of the lever is supported by springs, which can be expanded and contracted accordingly with the movement of the lever to ensure the tightness without venting.

Operation Method

When water is injected into the tube, the plug stays in the open position and a large amount of air is exhausted. When the air is exhausted, water accumulates in the valve, the floating ball is floated, the transmission plug head is closed, and a large amount of exhaust is stopped. When the water in the pipe is transported normally, if a small amount of air collects in the valve to a considerable extent, the water level in the valve drops, and the floating ball drops, and the air is discharged through the small hole. When the pump is stopped, when the water in the pipe is empty or when negative pressure is generated in the pipe, the plug is quickly opened at this time to suck in air to ensure the pipeline is complete.

Skills Requirement

1. Main technical parameters

The exhaust valve has a nominal pressure of PN10. The sealing test pressure is 1.1 MPa. The strength test pressure is 1.5 MPa. The water closing pressure of the exhaust valve should be less than 0.02 MPa. The air closing pressure of the exhaust valve should be more than 0.07 MPa. Maximum working pressure can reach 10bar. The maximum operating temperature is about 110 ° C.

2. Performance requirements

1) The exhaust valve should have a large exhaust volume. When the empty pipe of the pipeline is filled with water, the rapid exhaust can be restored to the normal water supply capacity in a very short time.

2) When negative pressure is generated in the exhaust valve in the pipe, the piston should be able to open quickly and suck a large amount of external air quickly to ensure that the pipeline will not be damaged due to negative pressure. And under the working pressure, the trace air accumulated in the pipeline can be discharged.

3) The exhaust valve should have a relatively high air closing pressure, and within a short time before the piston is closed, it should have sufficient capacity to exhaust the air in the pipeline to improve the water delivery efficiency.

Safety Exhaust Vent Valve

4) The water closing pressure of the exhaust valve should not be greater than 0.02 MPa. The exhaust valve can be closed at a lower water pressure to avoid a large amount of water gushing.

5) The exhaust valve should use stainless steel floating ball as the opening and closing member.

6) The valve body of the exhaust valve should be provided with an anti-shock protection inner cylinder to prevent premature damage to the floating ball caused by high-speed water flow directly impacting the floating ball after a large amount of exhaust.

7) The exhaust valve with a DN ≥ 100 adopts a split structure and consists of a large number of exhaust valves and automatic exhaust valves to meet the requirements of pipeline pressure. The automatic exhaust valve should adopt a complex lever mechanism, which can greatly enlarge the buoyancy of the float, and the closed water level is low. Impurities in the water will not easily contact the sealing surface, and the exhaust port will not be blocked. Its anti-blocking performance can be greatly improved. At the same time, under the condition of high pressure, due to the action of the double lever, the floating ball can be synchronized with the water level, and the opening and closing parts will not be sucked by the high pressure like the traditional valve, and the gas will be discharged normally.

8) For working conditions with high flow rate, frequent starting of the pump, and DN ≥ 100, in order to reduce the impact of water flow, the exhaust valve should be equipped with a buffer plug valve. The buffer plug valve should be able to prevent a large amount of water spray without affecting a large amount of exhaust, so that the water delivery efficiency is not affected, and effectively prevent water hammer.

I hope this passage can be helpful for you when you want to learn about the exhaust valve. If you want to learn more, please click :http://www.cnsunthai.com/Sanitary-Valve-pl8399805.html

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