Main technical parameters and performance requirements of exhaust valves

a. The nominal pressure of the vent valve is PN10.

b. The seal test pressure is 1.1 MPa.

c. The strength test pressure is 1.5 MPa.

d. The water shutoff pressure of the exhaust valve should be ≤ 0.02 MPa.

e. The air closing pressure of the exhaust valve should be ≥ 0.07 MPa.

f. Pressure test shall comply with the provisions of the standard GB/T13927.

g. The connecting flange should meet the requirements of the standard GB/T17241.6-98.

2 performance requirements

a. The exhaust valve should have a large amount of exhaust gas. When the pipe empty pipe is filled with water, it can be quickly discharged to normal water supply capacity in a very short time.

b. When the exhaust valve generates negative pressure in the pipe, the piston should be able to open quickly and quickly inhale outside air in large quantities to ensure that the pipeline will not be damaged due to negative pressure. And under working pressure, it can discharge the concentrated air in the pipeline.

c. The exhaust valve should have a relatively high air closing pressure. Within a short time before the piston is closed, it should have enough capacity to exhaust the air in the pipeline and improve the efficiency of water delivery.

d. The water shut-off pressure of the exhaust valve should not exceed 0.02 MPa, and the exhaust valve can be closed at a lower water pressure, thus avoiding the large amount of water escaping.

e. Exhaust valve should use stainless steel float (float) as the opening and closing parts.

f. The exhaust valve body should be equipped with an impact protection inner cylinder to prevent the high-speed water flow from directly impacting the float (float) and causing premature damage of the float (floating tank) after a large amount of exhaust.

g. For the exhaust valve with DN ≥ 100, a separate structure is used, consisting of a large number of exhaust valves and an automatic exhaust valve to meet the requirements for the use of pipeline pressure. The automatic exhaust valve should adopt a double lever mechanism, so that the buoyancy of the float ball can be greatly enlarged, and the closed water level is low, impurities in the water are not easy to contact the sealing surface, and the exhaust port is not blocked, and the anti-clogging performance thereof can be greatly improved. At the same time, under the condition of high pressure, due to the forcing effect of the double lever, the float can synchronously decrease with the water level, and the opening and closing parts will not be sucked by the high pressure like the traditional valves, so that the exhaust can be performed normally.

h. For operating conditions with high flow rates, frequent starting of pumps, and bore size DN ≧ 100, in order to mitigate the impact of water flow, the exhaust valve shall be equipped with a buffer plug valve. Buffer plug valve should be able to prevent a large number of water spray but does not affect a large number of exhaust, so that water delivery efficiency will not be affected, and effectively prevent the occurrence of water hammer.