FAQ

Cooling tower noise control plan and the cause of noise

Author：Trlon Views: Time:2020-12-11

　　Cooling towers are usually placed around residential areas and offices. Constant noise damage will interfere with the quality of life and mental health of customers. This has prompted the noise control of cooling towers to attract increasing attention. Today, the Kangming energy-saving air conditioner manufacturer will discuss its noise generation principle and how to formulate a reasonable and effective solution to everyone.

　　Cooling tower is a type of heat exchange equipment, and its noise basically has three factors:

　　1. The noise generated by the cooling tower fan

　　Basically, it can be divided into the equipment noise of the cooling fan and the aerodynamic noise of the fan inlet and exhaust pipes, which are characterized by low frequency. The fan used above the cooling tower is mainly drawn out in reverse to meet the purpose of temperature reduction. The high-speed rotation of the fan will produce aerodynamic noise. Several leaves in the rotation effect the airflow, and then cause the air pressure and the speed of the movement to be pulsating. The unbalance of the rotating parts will cause the structure to vibrate, and then generate vibration. noise.

　　2. Noise caused by falling water in cooling tower

　　The circulating water of the cooling tower falls from the spray pipe above, and the impact noise is generated according to the free fall motion, which is positively related to the square of the falling water speed and inversely proportional to the fourth power of the collision water surface.

　　3. Noise of cooling tower speed components

　　The noise of cooling tower equipment basically comes from the vibration of machine parts. The accessories of the machine will be elastically deformed during work, and then vibrate. When the elastic mechanical parts do not propagate to the surface of the radiation source, they will spread out according to the air and generate equipment noise.

　　Control method of cooling tower noise

　　Based on many years of professional noise control experience, and without disturbing all normal operation of the cooling tower, according to acoustic calculations, the comprehensive noise control plan for cooling towers is basically:

　　Setting a silencer at the inlet and outlet of the fan can reasonably and effectively block aerodynamic noise;

　　A sound-absorbing barrier is set around the cooling tower to reasonably and effectively reduce water spray noise and equipment noise;

　　Setting the air intake silencer shutters at the air inlet can ensure that the cooling tower can reasonably and effectively control the noise transmission when all normal ventilation and heat dissipation occur.

　　Relevant national industry standards involved in the treatment of cooling towers:

　　"Technical Specification for Division of Acoustic Environment Functional Zones" (GBT15190–2014)

　　"Social Life Environment Noise Emission Standard" (GB22337—2008) "Acoustic Environmental Quality Standard" (GB3096-2008)

　　"Law of the People's Republic of China on the Prevention and Control of Environmental Noise Pollution"

　　"Environmental Protection Law of the People's Republic of China"

　　"Building Engineering Project Management Code" (GB/T50306-2001)

　　"Construction Site Safety Production Assurance System" (GB50016-2006)

　　"Code for Construction Quality Acceptance of Steel Structure Engineering";

　　"Code for Design of Steel Structures" GB50017-2003;

　　"Welding Specification for Steel Structures" GB50661-2011;

　　Technologies used in cooling tower noise reduction:

　　1. Treating both symptoms and root causes and noise reduction treatment

　　It is a kind of scientific noise reduction processing technology, it is a kind of conscious noise reduction processing technology. Now that the noise source of the cooling tower is formed in the power components, the company uses the technical method of reducing the diameter to increase the installation of fans from four to Eight pieces, and change its length. According to the effective low-speed reducer, cooperate with the variable-frequency motor and use the magnetic levitation power platform. The principle is to reduce the noise by reducing the number of revolutions. Naturally, the prerequisite is not to change the air volume and do not reduce the efficiency. Noise processing.

　　2. Noise reduction processing and shielding technology:

　　The main noise source of the cooling tower is the upper exhaust noise, and its noise spectrum is mainly in the middle and low frequency. We can achieve the effect of noise reduction according to the method of installing a resistive muffler. The main factors that affect the silencing ability of the resistive muffler are:

　　The thickness of the sound-absorbing insert, the sound-absorbing material is usually filled with porous sound-absorbing materials, including Iear ultra-clean sound-absorbing panels, ultra-new glass wool, etc.;

　　The cross-sectional area of the air inlet and the reduction of the width of the air inlet will increase the silence volume of the muffler;

　　Muffler length;

　　3. Because the exhaust port of the cooling tower has been installed with a wind muffler, it can effectively reduce the noise of the exhaust port. In order to reduce the water spray and mechanical noise, a sound-absorbing barrier is designed around the cooling tower.

　　The sound-absorbing and sound-absorbing module of the noise barrier is made of sound-proof board + damping layer + porous sound-absorbing material + perforated guard board, and the actual insertion loss of the noise barrier is 15dB (A)

　　At the same time, in order to ensure ventilation and heat dissipation under normal conditions, air inlet silencer louvers must be installed above the noise barrier.

　　trlon professionally engages in the design and construction of noise control, sound insulation and noise reduction/vibration control engineering for industrial and civil heating equipment, refrigeration equipment, and ventilation equipment such as air conditioning unit noise control, cooling tower noise control, and heat exchange station noise reduction treatment. In the specific noise control and governance, the company adopts unique control and governance methods according to the characteristics of various types of noise: effective combination of isolation, elimination, absorption, and reduction, so that the project meets the standards and is tested in accordance with the national standards.

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