Pneumatic valves are common problem of congestion logistics

when the process fluid velocity within the pneumatic valve or reach the speed of sound within the downstream pipeline, the gas and steam produced jams logistics. When the fluid inside the pneumatic valve to the district of pneumatic valve throttle, pressure drop and the specific volume increase until reach the speed of sound. When the clogging of logistics, the velocity limit the amount of traffic that can pass on that point, and unless operating change velocity can no longer increase. In the operation of liquid caused by air pockets or flash steam bubbles, obviously increased the fluid volume, this increase in speed is faster than differential pressure produced. Under the condition of liquid blocking logistics, if the upstream pressure constant, lower downstream pressure does not increase traffic. In the operation of gas, in the pneumatic valve downstream of any part or line velocity is limited in Mach ( The speed of sound) 。 As a result, the flow rate of the gas will be limited to pneumatic valve pneumatic valve core or reach a velocity of flow downstream piping.