Firstly, the abrupt change of cross section (i.e. the change of reactance) of the pipeline is used to make the sound wave propagating along the pipeline reflect back to the direction of the sound source, so that the sound energy can be reflected back to the original place.
The second is to use the reflection of several interfaces to make the first forward-propagating sound wave return to its origin and then turn back to propagate forward again. The point converges with the second forward-propagating sound wave that has not yet been reflected, and the two are equal in amplitude and 180 degrees odd in phase, thus interfering with each other and canceling out.
It is mainly used to reduce the noise of intake and exhaust of Roots series and axial flow series fans. It can also be used to reduce the noise of exhaust pipes and other high-pressure fans. The noise reduction capacity is 15-30 dB (A), and the pressure loss is less than 500 Pa.
According to the spectrum characteristic data obtained from the actual test of various noise sources in industrial fan operation site, the main basis for designing sound absorber and fluid channel is to determine how much noise reduction is needed in which spectrum range. At the same time, a narrow rectangular channel with large sound absorption material is adopted to enhance the absorption effect. In addition, when the noise source of the fan is at the maximum noise level, its spectrum value is often more than one, and for different spectrum bands, the requirement for noise reduction is also different. For this reason, the series of ventilation duct mufflers and the mufflers of blower and induced draft fan are all impedance sound flow type. The resistance type structure which can absorb and muffle high and intermediate frequency noise and the resistance type structure which can muffle and muffle medium and low frequency noise are adopted. At the same time, two kinds of high and low frequency sound absorption and muffling zones are adopted in the resistance type channel to maximize the muffling frequency band so as to achieve good muffling effect. Noise reduction effect
Boiler ignition exhaust muffler (TB) is designed to suppress noise emitted by high pressure steam flow. Nowadays, there are many kinds of mufflers in the world. Its principle mostly adopts multi-stage throttling to reduce pressure. Because of its complex structure, large weight and difficulty in dismantling and repairing, its application scope is limited. The muffler with the new structure overcomes the above shortcomings.
The exhaust muffler system of this type synthesizes the most reasonable muffling principle. High pressure steam enters the depressurizer after a flow control in the exhaust muffler and after a large volume expansion, the noise is still higher than the standard value due to the deviation of the exhaust steam from the design value and other reasons. For this reason, a double-layer structure acoustic shield is designed in the depressor, which is based on the spectrum characteristics of the residual noise emitted by the depressor to absorb the residual noise effectively. When the user installs it according to the requirements, the total noise will reach 36-42 decibels.
Ningbo Fenghua Yongqiang Filtration Equipment Co.,Ltd
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Address: 88 Jinhe Road, Xiaowangmiao Street, Fenghua District, Ningbo City
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