Why is it necessary to install and set up an air vent in a water supply pipe?
The exhaust valve is installed at the outlet of the pump or in the water supply and distribution pipeline to remove a large amount of accumulated air in the pipeline to improve the efficiency of water pipes and pumps. If negative pressure occurs in the pipeline, the exhaust valve can quickly Inhale air to avoid damage caused by negative pressure in the pipeline.
How the exhaust valve works?
When the water pump stops working, negative pressure will be generated at any time, and the float will drop at any time, and a large amount of air will be sucked to ensure the safety of the pipeline. In the exhaust state, the float pulls down one end of the lever due to gravity. At this time, the lever is in an inclined state, and a gap appears in the contact part between the lever and the exhaust hole.
The air is discharged from the exhaust hole through this gap. As the air is discharged, the water level rises, the float floats upward under the buoyancy of the water, and the sealing end face on the lever gradually presses against the exhaust hole until the entire exhaust hole is completely Blocked, the exhaust valve is now completely closed.
Things to note when setting up the exhaust valve:
1. The exhaust valve must be installed vertically, that is, the float inside it must be ensured to be in a vertical state to avoid affecting the exhaust.
2. When installing the exhaust valve, it is best to install it together with the isolation valve, so that when the exhaust valve needs to be removed for maintenance, the system can be sealed and water cannot flow out.
3. The exhaust valve is generally installed at the highest point of the system, which is beneficial to improving exhaust efficiency.
The main functions of the exhaust valve:
The function of the exhaust valve is mainly to remove the air inside the pipeline. Because there is usually a certain amount of air dissolved in water, and the solubility of air decreases as the temperature increases, the gas gradually separates from the water during the circulation process, and gradually gathers together to form large bubbles or even air columns. Because there is water replenishment, gas is often produced.
Performance requirements of the exhaust valve:
1. The exhaust valve should have a large exhaust volume, when the pipeline empty tube filled with water can be achieved in a very short period of time to quickly exhaust back to normal water supply capacity.
2. The exhaust valve in the tube when there is negative pressure, the piston should be able to quickly open, a large number of rapid inhalation of outside air to ensure that the pipeline does not produce damage due to negative pressure. And in the working pressure can be the pipeline in the collection of trace air discharge.
3. The exhaust valve should have a relatively high air closing pressure, in a relatively short period of time before the piston closes, there should be sufficient capacity to discharge the air in the pipeline to improve the efficiency of water delivery.
4. The water shut-off pressure of the exhaust valve should be no greater than 0.02 MPa, the exhaust valve can be closed at a lower water pressure, thus avoiding a large amount of water gushing out.
5. The exhaust valve should use stainless steel floating ball (floating barrel) for opening and closing parts.
6. The exhaust valve body should be equipped with anti-impact protection cylinder, to prevent a large number of exhaust after the high-speed water directly impact the float (float bucket) and cause premature damage to the float (float bucket).
7. For DN ≥ 100 exhaust valve using split structure, by a large number of exhaust valve and automatic exhaust valve composition, to adapt to the use of pipeline pressure requirements. Automatic exhaust valve should use the compound lever mechanism, so that the buoyancy of the float can be greatly enlarged, and close the water level is low, impurities in the water is not easy to contact the sealing surface, the exhaust port will not be blocked, its anti-clogging performance can be greatly improved.
At the same time in the case of high pressure, due to the force of the compound lever, so that the float can be synchronized with the water level down, the opening and closing parts will not be like the traditional valve is high pressure suction, so that the normal exhaust.
8. For high flow rates, frequent start-up pumps, DN ≧ 100 calibre working conditions, in order to slow the impact of water flow, exhaust valve should be installed with a buffer plug valve. Buffer plug valve should be able to prevent a large amount of water spray but does not affect a large number of exhaust, so that the efficiency of water delivery will not be affected, and effectively prevent the occurrence of water hammer.
