Analysis of Noise Sources in Cooling Towers and Treatment Methods
Author：Trlon Views: Time:2020-11-11
Noise pollution has always been the number one global environmental problem in the world, and long-term exposure to low-frequency noise pollution will cause serious harm to the human hearing system, nervous system, cardiovascular and cerebrovascular, mental state, and absorption and digestion system management. When the closed cooling tower is in operation, the key is to use large, medium and small radiator blades to cool the hot water. Because the centrifugal fan of the cooling tower causes operating noise pollution, eddy current noise pollution and industrial equipment noise pollution during operation. This kind of cooling tower noise pollution frequency band has the characteristics of wide-screen band, namely low frequency. Its noise pollution value is not particularly large, but it gives people a sense of depression and depression. It will affect the surrounding residential users and construction, and it is also one of the causes of other noise sources, so sound insulation and noise reduction must be implemented.
Analysis of noise source of cooling tower
1. Noise pollution of centrifugal fan
It is a key noise source of natural ventilation cooling towers for industrial equipment. The noise pollution is air power energy noise pollution, mainly including seepage noise pollution and operation noise pollution. According to the specific analysis of air power energy noise sources, the sound intensity level of seepage noise pollution is proportional to the sixth square of the certain velocity of the airflow, which is also related to the appearance design of the blade product, and there is a continuous frequency band characteristic. Running noise pollution is caused by pulsating beverages when the blades are running. It is related to the number of blades, air pressure, negative pressure, etc., and its frequency band is characterized by low and high frequencies.
2. Noise pollution from water splashing (i.e. water falling noise pollution)
It is caused by the impact of the water spraying equipment of the cooling tower with the water storage in the lower tower chassis. The noise pollution level is related to the aspect ratio of the water falling into the water and the water output during the control module time. The same is usually the only centrifugal fan Noise pollution and high frequency characteristics. The water drop noise pollution of the cooling tower is usually only lower than the centrifugal fan in the noise pollution of the cooling tower. When the noise pollution of the centrifugal fan drops, the noise pollution of the water spray takes the core part. Depending on the cooling tower model and specifications, sometimes the noise pollution of this centrifugal fan is also large, the same usually depends on the tower height, the water output and the distance between the tower body filling materials.
3. Noise pollution of reducer and electricity
The key to the noise pollution of the reducer is the noise pollution caused by gear meshing. The same is true if the processing accuracy is high, the noise pollution is not large. The noise pollution of the reducer has little harm to the total noise of the cooling tower. Therefore, in addition to the noise pollution surrounding the cooling tower and the total falling noise pollution, such noise pollution may be negligent. The base of other reducers is equipped with anti-vibration materials to prevent possible noise pollution. Electrical noise pollution refers to electromagnetic induction noise pollution and equipment noise pollution. These two types of noise sources are equally harmful to the surrounding environment and may be negligent. The noise pollution of centrifugal fans is lower than the noise pollution of reducers, so there is no need to classify and deal with noise in all aspects.
4. Noise pollution of water pump
The cooling tower is equipped with a circulating water pump adjacent to the tower, and its noise pollution is particularly large compared with other sound sources. The controllers of other water pumps are usually power consumption or steam controllers, which are also a strong source of noise. The water pump is arranged adjacent to the cooling tower to circulate and cool the circulating water. It often oscillates with the tap water pipeline to produce high-frequency and high-profile noise pollution. If the compressive strength of the noise pollution is very high, it must be treated together.
5.Cooling tower water pump
This type of noise is not a trickle hazard to the natural environment when used in objective facts. It is only in operation, when the water flow of the pipeline is insufficient or the throttle valve of the gate valve is not good enough to cause the inverse ear and the ear flow field. Normally, only mediation is in power. The prerequisites can be rectified.
Cooling tower noise treatment method
Regarding the reason and dissemination method of noise, the rectification of cooling tower noise will be translated into two basic methods of tower body and outside of the tower. The tower body is dominated by noise reduction at the sound source; the outside of the tower includes sound transmission. There are three ways of acoustic frequency isolation (sound insulation), acoustic frequency acceptance (acceptance of attenuation coefficient along the joint) and attenuation coefficient of spacing (external sound diffusion). Among them, sonic frequency isolation plus sonic frequency acceptance is the key way to renovate the tower exterior. Whether it is the remediation method of the sound source of the tower body or the existing overseas acoustic frequency isolation method, the specific and application in China has tended to perfect. What are the key points of cooling tower noise control methods:
: Control the noise of the inlet and outlet of the exhaust fan of the cooling tower. Special silencers can be made at the inlet and exhaust system of the cooling tower. For cooling towers with protruding air inlet and outlet noise, this method has a significant adverse effect on noise reduction;
2) Noise barrier
: Setting up a noise barrier, combining the sound insulation structure of natural ventilation shutters and sound insulation panels into a suitable sound insulation structure is a reasonable way to lower the overall noise of the cooling tower. This kind of sound insulation structure will reduce the noise of cooling tower intake and exhaust pipes, water splashing noise, electrical ideas and mechanical equipment noise of electrical equipment.
3) Silencer pad
: The silencer pad is placed on the water tray, which is a reasonable way to drop the noise of the cooling tower.
4) Shock absorber and vulcanized rubber conductive soft connection:
the equipment damping spring shock absorber between the cooling tower foot and the road surface, the equipment rubber soft connection in the pipeline, in addition, if the cooling tower is on the flat roof service platform, it needs to be connected between the pipeline and the flat roof The shock absorber or cushion is set in the surface connection, and the above method can greatly reduce the harm and noise caused by vibration.