How to deal with electric single-seat control valve noise

Electric single-seat control valve is a pressure-balanced control valve. Accept the regulation instrument to the DC current signal, change the media to be adjusted to make the controlled process parameters at a given value. Widely used in electric power, metallurgy, chemical industry, petroleum, textile, pharmaceutical, paper and other industrial sectors of production automation and control. However, on the electric single-seat control valve noise can not be avoided in the work, then how to deal with electric single-seat control valve noise? What are the measures? 1, the use of thick-walled pipe method thick-walled pipe is one way to deal with the sound path. The use of thin walls can increase the noise by 5 dB, the use of thick-walled tubes can reduce noise by 0 to 20 dB. The same diameter wall thicker, the same wall thickness greater diameter, the better the noise reduction. Such as DN200 pipe, the wall thickness was 6.25,6.75,8,10,12.5,15,18,20,21.5mm, the noise can be reduced to -3.5, -2 (ie increase), 0,3,6, 8, 11, 13, 14.5 dB. Of course, the thicker the wall, the higher the cost of the rotor pump. 2, to eliminate the resonance noise method Only electric single-seat control valve resonance, only the energy superposition and produce more than 100 dB strong noise.Some performance is strong vibration, noise is not large, and some vibration weak, but the noise is very large; Some vibrations and noises are large, and the noise produces a single-tone sound with a frequency of 3000-7000 Hz. Clearly, the elimination of resonance naturally disappears. 3. Elimination of cavitation noise method Cavitation is the main source of hydrodynamic noise, and when cavitation, the bubbles burst to produce high-speed impact, causing strong turbulence locally and generating cavitation noise. This type of noise has a wide frequency range and produces a treble sound similar to the sound of gravel contained in a fluid. Eliminating and reducing cavitation is an effective way to eliminate and reduce noise. 4, the selection of low noise valve low noise valve According to the fluid through the control valve spool, valve seat of the tortuous flow path (multi-channel, multi-channel) of the gradual deceleration to avoid any point in the flow path to produce supersonic. A variety of forms, a variety of structures of low-noise valves (designed for specialized systems) for use when used. When the noise is not large, the choice of low noise sleeve valve, can reduce the noise 10 to 20 dB, which is the most economical low noise valve. 5, the use of sound-absorbing material method This is also a more common and most effective way to deal with the sound path. Sound-absorbing material can be used to surround the noise source and the valve after the pipeline. It must be pointed out that because of the long-distance propagation of noise through the fluid flow, where the sound-absorbing material is wrapped and where thick-walled tubes are used, the effectiveness of noise cancellation ends. To some extent, this is a way to deal with electric single-seat control valve noise cost a maximum! 6. Series throttling method When the pressure ratio of the regulating valve is high (ΔP / P1≥0.8), the series throttling method is to divide the total pressure drop in the fixed throttling element after the regulating valve and the valve. Such as the use of diffusers, porous restrictor, which is the most effective way to reduce noise. In order to get the best diffuser efficiency, the diffuser (physical shape, size) must be designed for each piece of installation so that the valve produces the same noise level as the diffuser. 7, Tandem muffler method This law applies to silence as aerodynamic noise, which can effectively eliminate the noise inside the fluid and inhibit the noise level transmitted to the solid boundary layer. This method is most effective and economical for places with high mass flow rate or high pressure drop before and after the valve. The use of absorption series silencer can significantly reduce the noise. However, economically, it is generally limited to decay to about 25 dB.