Solutions to noise and cavitation problems in the use of pneumatic control valves

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In practical applications, the noise generated by pneumatic control valves is a major source of pollution in petrochemical production. Cavitation and noise are two important issues in high-pressure differential flow control. 1. Mechanical vibrations – for example, when the valve element of a pneumatic control valve moves horizontally within the sleeve, it is possible to minimize the gap between the valve element and the sleeve, or use a sleeve with a hard surface. 2. Mechanical activity of the medium – When the medium moves within pipes or pneumatic control valves, it can also generate noise; we will not go into detail regarding this phenomenon. Of course, cavitation can also cause noise. 3. Natural frequency vibration — Components such as the valve spool of pneumatic control valves or other similar parts all have a natural vibration frequency. The characteristics of the valve spool can be altered through specialized casting or processing methods, and if necessary, different types of valve spools can be used as alternatives. 4. When the cause is instability of the valve spool—such as noise resulting from pressure fluctuations in the fluid due to vibratory displacement of the spool, this situation is usually caused by damping factors in the control loop actuators, etc.; in such cases, the damping coefficient can be adjusted again or vibration-damping devices can be added in the direction of the spool’s displacement.