Control Valve noise sometimes up to 100 DB or more, making it difficult to bear people close to it. General control valve noise from the vibration of the spool, there are high-speed airflow generated by the gas dynamic noise, but also because of flashing, cavitation, flow caused by liquid dynamic noise.
Prevention and reduction of vibration and noise. Most of this kind of noise is caused by resonance, vibration is often accompanied by noise, but there are large and small. Noise can be reduced by increasing stiffness to increase damping, reducing throttling fit, guiding clearance to reduce lateral vibration, and so on; the fundamental means of prevention is not to weaken or deaden the noise by passive means It’s about eliminating resonance, changing the natural frequency of the valve.
Prevention of cavitation noise. In the same way, the air noise should be considered from preventing flash, preventing cavitation or reducing flash and reducing cavitation.
Prevention of aerodynamic noise. When the speed of the compressible fluid passing through the control valve is greater than or equal to the speed of sound, there will be strong noise and vibration, which will not only produce noise, but also damage the parts. The degree of damage of this noise is related to the noise energy And the energy of the noise is proportional to the third power of the velocity. Therefore, the greater the speed, the greater the noise will be.
Currently, there are 5 general ways to avoid aerodynamic noise:
1. Eliminate noise sources by radically limiting the throttle speed of the regulator below the speed of sound.
2. The low noise control valve is selected, which makes the fluid flow zigzag when throttling, interfere with each other and collide with each other, in order to increase resistance, consume energy, prevent (or reduce) any point in the flow path to produce supersonic speed, thus reducing the noise. When the noise is not very big, may choose the ordinary sleeve valve.
3. The porous restrictor plate is used to absorb the partial pressure drop behind the valve to increase the pressure behind the valve and reduce the throttling speed to reduce the noise.
4. Noise insulation material is used to reduce noise. When the noise is low, use sound insulation material to cover the pipe behind the valve until the noise is below 80 DB.
5. Use silencer, when the noise is slightly high, install the silencer behind the valve to absorb the noise and reduce the transmission.
Post time: Jul-28-2021