Weak current College】 【control valve common troubleshooting methods (5).

<br> 7. control valve noise solution (8 way) <br> 1) eliminate resonance noise law <br> Only the control valve, a resonance energy superposition and 100 DB's strong noise. There's a strong performance for the vibration, noise and .vibration are weak, but the noise is very big; vibration and noise are larger. This type of noise to produce a single tone of voice, its frequency is usually 3000-7000 Hz. Obviously, eliminate resonance, noise nature disappear. Methods and examples .see 4.5 4), 5), 6). <br> 2) eliminate cavitation noise law <br> Cavitation is the main source for fluid power noise. Cavitation bubble burst when produce high-speed impact, its local produce severe turbulence, cavitation .noise. This type of noise has a wide range of frequencies, rattle, and fluid containing sand and sound similar. Eliminate and reduce cavitation is eliminate and reduce the noise of effective approaches. <br> 3) use of thick-line method <br .> Use of thick-walled tube is one of the acoustic road approach. Use the shell to enable noise increase 5 decibels, the use of thick-walled tube makes noise reduction of 0 to 20 DB. The more of the same diameter, wall thickness .of the tube diameter of the same wall thickness, the better the effect of reducing the noise. If the wall thickness of pipes, DN200 respectively 6.25, 6.75, 8, 10, 12.5, 15, 18, 20, 21.5mm, reduces noise respectively .-3.5, -2 (ie increase), 0, 3, 6, 8, 11, 13, 14.5 DB. Of course, the more thick walls of the cost. <br> 4) using sound absorbing materials method <br> This .is one of the more common and most effective sound road approach. Available sound-absorbing material placed over the source of the noise after the pipeline and valves. It must be pointed out that, because of the noise through fluid flow and long distance communication, .where acoustic material package, the use of thick-walled tube to where the validity of the Elimination of noise in respect of the termination. This approach does not apply to noise is high, the pipeline is not very long, because this is a more expensive .solution. <br> 5) series muffle method <br> This law applies to as aerodynamic noise silencers, it can effectively eliminate fluid internal noise suppression to solid boundary layer of the noise level. On mass flow valve before and after high or high pressure .drop ratios, of this law, the most effective and affordable. Using the absorption-line silencer can substantially reduce noise. However, economic considerations, generally limited to decay to about 25 DB. <br> 6) enclosures method <br> The use .of enclosures, houses and buildings, noise isolation inside so external environmental noise is reduced to acceptable range. <br> 7) tandem throttle method <br> In the control valve pressure is high (△ P/P1 = 0.8), in-line .cutting method, is to the total pressure drop across the control valve and the valve after fixed throttling element. As with diffuser, porous current limiter plate, this is to reduce noise in the most effective way. For best efficiency, of the diffuser must be .each installation to design diffuser (entity shape, size), so that the noise level of valves and diffuser produces a noise level of the same. <br> 8) selection of low noise valve <br> Low noise valve fluid through the valve, .valve seat of tortuous stream road (multiple channel, multi channel) gradually slow down to avoid flow path anywhere in produce supersonic. There are a variety of forms, a variety of structures of low noise valve (for specialized system design) available for use. .When the noise is not very large, using low-noise sleeve valve to reduce noise in for 10 ~ 20 decibels, which is the most economical, low-noise valve. <br>.