Self-operated steam reducing valves can be squeezed against each other by pressure or "compression" of a mechanical device or process fluid. In most cases, the elastomer of the heating remote control valve is a complete bushing that connects the entire flow path to the flange. During the period when the control medium does not enter, the cavity between the rubber sleeve of the pinch valve and the valve body is communicated with the atmosphere, and the rubber sleeve is pulled outward due to the pressure of the fluid. Closing the self-operated steam reducing valve A potential problem can occur behind the valve. This problem can be explained by the breaking of the flow column, as well as by the inertia that carries the flow column away from the closing valve, while the adjacent space is occupied by bubbles, in short, in a virtual vacuum. If there is enough back pressure in the pipe, the velocity of the fluid water column will reverse; The fluid fills the vacuum created by the fluid water column breaking, creating another pressure surge when the fluid column reaches the valve.

Slow closing is beneficial to limit the phenomenon of pressure fluctuations. In large, long-distance liquid pipelines, it is important to estimate the possibility of pressure fluctuations and limit the average closing speed of cut-off valves. When operating the self-operated steam reducing valve or adjusting the operating speed of the power operating valve, the design of the valve closing speed should be carefully considered. The rapid closing of the electric gate valve on the flowing liquid pipeline will cause a large pressure fluctuation, which will emit a violent "shock" sound or may emit a series of frequent "shock" sound. This phenomenon should be limited not only to water pipelines, but also to other liquid pipelines. When closing a shut-off valve in a flowing liquid pipeline, avoid quick closing, especially during the stem travel phase.