Dual-port exhaust valve was born in the 70's, large size, heavy weight, small exhaust volume, the exhaust room in the late 80's the most ideal product, has been continued to use. The exhaust room is the necessary equipment for the pipeline. it is installed at the highest point of the pipeline or at the place where the air is closed to drain the gas in the pipeline, to dredge the pipeline, and to make the pipeline run normally. if the power is cut off, negative pressure will appear in the pipeline, which will cause the pipeline to vibrate or burst, the oxygen discharge vaive breathes in time to ensure the safety of the pipeline.
Characteristic principle:
1. In the absence of water pressure （E. G. in a constructed circle） , the float and disc are lowered into the sheath. When the pipe is filled with water, a great deal of air is discharged from the large exhaust port.
2. When the air is nearly exhausted, the water vaive starts to float the float into the vaive. The float lifts the valve and stops the water from flowing out.
3. After the vaive disc block large exhaust port, as long as the water and gas in the pipeline pressure state, the vaive disc will not fall. If the air in the pipe builds up to a certain amount in the exhaust valve, it will fall due to the reduced buoyancy of the float, and the air will be discharged through the small exhaust hole in the guide Rod. After the air is exhausted, the float rises and blocks the small vent.
4.When negative pressure is generated in the pipe, the disc and float are sucked down and a large amount of air is supplied from the large exhaust port.
