Technical measures and treatment plan for cooling tower noise

General measures for noise management are: controlling noise sources, cutting off transmission routes, and protecting victims.The noise of the cooling tower affects the health and daily life of the operators and residents. The victims are extensive and the mobility is large. Therefore, the measures to protect the victims are not feasible. Only measures to control the noise source and cut off the transmission route can be taken.The principle of the sound insulation screen is: using sound wave diffraction to make the sensitive building in the sound shadow area, to achieve the purpose of reducing the sound level.

For the noise characteristics of the cooling tower, the following measures are usually taken.

(1) Replace the normal motor blades with low noise blades to reduce the noise level from the source.

(2) Exhaust noise has continuous spectrum characteristics, and sound absorption should be considered.The sound absorbing channel is made of a waterproof sound absorbing body to achieve the purpose of noise reduction.

(3) Avoid mechanical resonance to generate noise, the hard connection of the cooling tower should be vibration reduction treatment.

(4) Add quick-filter filling to the water tray to reduce water spray noise.

(5) The tower body and the water pump are surrounded by a waterproof sound absorption barrier to cut off the noise transmission path.

Cooling tower noise governance plan

(1) When the noise sensitive area is higher than the cooling tower, the sound barrier has a limited sound insulation effect.Installing a muffler at the air inlet and outlet of the cooling tower will affect the cooling effect, and the long-term contact of the muffler with water vapor will also affect the effect.Sound insulation room has obvious noise reduction effect, but the cost is higher.Therefore, in the process of noise control, it is necessary to adapt to local conditions and fully consider various complicated situations, and choose an appropriate treatment plan.

(2) In view of the fact that there is supplying no fan cooling towers on the market, and the noise level of such cooling towers is below 60 dB, the users generally report good after use. Therefore, it is recommended to promote the use of new environmentally friendly cooling towers.

(3) Reasonably determine the location of the cooling tower.In the specified building land, the cooling tower should be located as far as possible from the buildings that need to be quiet (including this building and surrounding buildings).Noise is weakened by increasing distance.In free space, when the distance is doubled, the noise level is reduced by 6dB (when the sound source is the point source and the surrounding silent reflection).In fact, due to the acoustic reflection of the surrounding buildings, and the cooling tower is not a point source, the noise is attenuated by about 3-4 dB when the distance is doubled.It is generally easy to do in the construction of the factory. At the same time, the side with the strong source of the cooling tower is directed to the side that does not need to be quiet, and the warehouse and commercial building are arranged between the cooling tower and the front area where the plant needs to be quiet. Effectively control the noise interference of the cooling tower.

In civil buildings, especially in large and medium-sized cities, where the construction land is greatly restricted, it is difficult or even impossible to keep the cooling tower away from this building or group of buildings.In high-rise buildings, such as hotels, apartments and office buildings, it is impossible to ensure the cooling requirements of the tower even if it is possible to stay away from the cooling tower.Therefore, the cooling tower is usually installed on the roof of a building. In this case, only low-noise cooling towers and sound insulation measures can be used.

（4）Design and use a low noise cooling tower.The noise sources of the cooling tower are fan noise, water fall noise, reducer noise, motor noise, valve parts noise and cooling pump noise, but mainly the fan and water fall (water spraying) noise.

Reducing fan noise is a positive measure to reduce the noise of the cooling tower. For example, low-speed, large-diameter, new-leaf, wide-blade, small-leaf angle, belt drive and other measures can effectively reduce the noise of the blower unit.The noise reduction is about l0dB, usually up to the A sound level.

In addition, two-speed motors are used depending on the temperature difference between day and night or the operating load.When the daytime temperature is high and the production is running at full capacity, the cooling tower motor will reach 100% operation;when the temperature is low at night and the capacity of the cooling tower is reduced, the motor should run at 2/3 or 1/2 speed.In this way, the noise of the fan will be reduced accordingly, so as to adapt to the lower allowable value of the night city area.

Although the location, floor space, sound source distribution, and functional area of each large cooling tower are different, as long as the noise control design principles are mastered, the mechanism and characteristics of the sound source are analyzed in combination with specific conditions.Then choose the corresponding governance measures, it is completely able to effectively solve the pollution problems of various large cooling tower noise.