What reason can make the fine small electric regulating pneumatic valve noises

Essence small electric regulating pneumatic valve using small Angle travel electric actuators, and pneumatic valve, pneumatic valve. Electric actuators with servo amplifier, to match the servo amplifier, they should not be input control signals ( 4 - 20 madc or 1-5 VDC) Single-phase power can control operation, and realize the parameters such as pressure, flow, temperature, liquid level adjustment. The pneumatic valve has a small volume, light weight, simple wiring and large flow, high accuracy, etc. Flow characteristics of the commonly used: percentage features (such as Also called logarithmic) And linear ( Also called linear features) , and the characteristics of quick opening. The regulation of linear features in small open degree, flow relative changes value, high sensitivity, but not easy to control, and when the big opening, flow relative changes little. Such as the adjustment of the percentage features in a small open of the pneumatic valve, flow relative change value is small, adjust the balance, and when the big opening, big flow relative changes.
fine small electric regulating pneumatic valve application:
in the oil, natural gas, coal and ore mining, refining processing and pipeline system;
in the operation of chemical products and food;
in the water and electricity, thermal power and nuclear power management system;
in the urban and industrial enterprise of water supply and drainage, heating and gas supply system;
in the farmland irrigation and drainage systems; In metallurgical business systems;
in use will adjust fine small electric pneumatic valve makes a noise, what reason be cause?
1, the vibration noise. This kind of noise caused by resonance, and some show the strong vibration noise is small, some weak vibration noise big, some are big vibration and noise. Obviously, eliminate resonance, noise disappear naturally.
2, fluid dynamic noise. For pneumatic control valve, fluid dynamics of cavitation is the main noise source. A high-speed impact cavitation bubble breakage, make its local produce strong surge flow, the formation of cavitation noise. This noise cackle, similar to the sound of a fluid containing sand, should prevent or reduce the flash and take measures on the cavitation.
3, aerodynamic noise. When compressed fluid by electric adjustment, the speed of the pneumatic valve is greater than or equal to the speed of sound will be produced in strong noise. The greater the speed, the greater the noise will be. Stop the aerodynamic noise limit is the basic way of electric control pneumatic valve throttle speed, lower than the speed of sound.