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This post was last edited by tianyewei on 2017-12-4 10:45 Roots blower is a typical positive displacement blower. It relies on the change of rotor volume to convert the mechanical energy added by the prime mover into the pressure and kinetic energy of the gas. Compared with centrifugal blowers, it has the advantages of high pressure head, small flow rate affected by resistance, and stable air supply. However, it generally suffers from the shortcomings of low efficiency and high noise during use. Roots blowers are widely used in factories. Because the loud noise produced by the blower worsens the working conditions and pollutes the living environment, people pay more and more attention to the noise of the blower. On the basis of comprehensive application examples, various methods for reducing noise are proposed. Roots blower noise sources Roots blower contains a variety of noise sources, the main parts of which radiate are:: 1. Aerodynamic noise radiated by the air inlet and outlet ； 2. Mechanical noise radiated by the casing, motor, bearings, etc. ； 3. Solid sound radiated by basic vibration ； Among these parts of noise, the aerodynamic noise radiated at the entrance and exit is the strongest. General methods for noise control of Roots blowers. For fans used on site, different control measures can be selected according to the size of the fan noise, site conditions and noise reduction requirements. Generally speaking, they can be summarized as installing silencers, adding sound insulation covers, modifying the fan room, or bandaging pipes. 1. Mechanical noise control method For the mechanical noise of Roots blower, the main control method is to improve the accuracy of assembly. ； Replace old ball bearings, or replace rolling bearings with sliding bearings to keep the rotor in dynamic balance ； Connect the motor and blower with a flexible coupling ； Strengthen the maintenance and repair of equipment, as well as refuel and lubricate, tighten connecting bolts, replace damaged parts, etc. These are all effective in reducing noise. 2. General control methods for aerodynamic noise 1). Install a muffler: Because under normal circumstances, the aerodynamic noise radiated from the fan inlet and exhaust port is 10-20 decibels higher than the noise radiated from other parts. Therefore, when controlling fan noise, you should first install appropriate mufflers on the intake and exhaust ducts. 2).Build a sound insulation cover: The sound insulation cover method is to surround the entire fan unit with a closed sound insulation cover. The sound insulation effect is good, but the use of a closed sound insulation cover will cause heat dissipation problems for the unit. The main cooling forms are: Self-fan ventilation cooling method, negative pressure suction cooling method, air circulation ventilation cooling method in the hood and external mechanical ventilation cooling method, etc. 3).Renovate the fan room: If the fan unit has a dedicated fan room, the existing fan room can be transformed into a soundproof room based on the site conditions. That is, the fan is enclosed in the fan room so that the noise cannot be transmitted out. The main technical measures are the use of soundproof doors, soundproof windows, soundproof screens and wall soundproofing, and the application of appropriate sound-absorbing materials. 4).Pipe bandaging: In order to reduce the noise radiated from the fan duct, the duct can be bandaged to isolate the way the noise propagates. 5).Vibration isolation: Taking into account factors such as safety, stability and ease of maintenance, appropriate vibration isolators are designed and selected to eliminate the rigid connection between the machine and the unit, thereby achieving the purpose of reducing solid vibration noise. You can also dig anti-seismic trenches to replace foundation vibration isolation, which can achieve certain results. In summary, as long as reasonable treatment methods are selected, most of the noise of the Roots blower can be reduced on a certain basis.