1) elimination of resonance noise method

Only when the regulating valve resonates, there is a superposition of energy to produce a strong noise of more than 100 decibels. Some are characterized by strong vibration, little noise, weak vibration, and very large noise; some vibration and noise are larger. This noise produces a single tone sound of 3000~7000 hertz. Obviously, resonance, noise elimination is clearly eliminated. Nature vanishes. Methods and examples see 4 of the above 4.5, 5), 6).

2) elimination of cavitation noise method

Cavitation is the main source of fluid dynamic noise. When cavitation occurs, bubbles rupture produces high velocity impact, causing local strong turbulence to produce cavitation noise. This noise has a wide frequency range and produces a grid noise similar to that emitted by sand in a fluid. Eliminating and reducing cavitation is an effective way to eliminate and reduce noise.

3) use thick wall pipeline method

The use of thick wall tube is one of the sound path treatment. The use of thin walls can increase noise by 5 dB. Using thick walled tubes can reduce noise by 0~20 dB. The thicker the same diameter wall is, the larger the thickness of the same wall will be, and the better the noise reduction effect will be. For example, when the DN200 pipe is 6.25, 6.75, 8, 10, 12.5, 15, 18, 20, and 21.5mm, the noise can be reduced to -3.5, -2 (or increase), 0, 3, 6, 8, 11, 13, and decibel. Of course, the thicker the wall is, the higher the cost will be. Rotor pump Custer red wine.

4) adopting the sound absorbing material method

This is also a more common and effective way to deal with sound path. Sound absorbing material can be used to encamp the noise source and the rear valve line. It must be pointed out that the noise can be transmitted over a long distance through the flow of fluid, so where the sound absorbing material is wrapped and where the thick wall tube is used, the effectiveness of the noise elimination will be terminated. This method is applicable to situations where the noise is not high and the pipeline is not very long, because this is a more expensive method.

5) series silencer method

This method is suitable for noise reduction as aerodynamic noise. It can effectively eliminate noise inside the fluid and suppress noise level transmitted to the solid boundary layer. This method is most effective and economical for high mass flow rate or high pressure drop ratio. The use of absorption series silencers can significantly reduce noise. However, economic considerations are generally limited to about 25 decibels.

6) sound insulation box method

Use sound boxes, houses and buildings to isolate noise sources, so that noise from external environment can be reduced to acceptable ranges.

7) series throttle method

When the pressure ratio of the valve is high (delta P/P1 > 0.8), the series throttle method is used to disperse the total pressure drop on the fixed throttle element after the valve and the valve. Such as diffuser and multi hole limit plate, which is the most effective way to reduce noise. In order to get the best diffuser efficiency, it is necessary to design the diffuser (the shape and size of the entity) according to the installation of each piece, so that the noise level produced by the valve is the same as the noise level produced by the diffuser.

8) select low noise valve

The low noise valve slows down the tortuous flow through the valve spool and the valve seat by the fluid to avoid the supersonic speed at any point in the flow. There are various forms of low-noise valves with various structures (specially designed for use) when used. When the noise is not very large, the selection of low noise sleeve valves can reduce noise by 10~20 dB, which is the most economical and low noise valve.