谈矿用局扇噪音及消除方法（Talking about the noise of mine bureau fan and its elimination method）

谈矿用局扇噪音及消除方法（Talking about the noise of mine bureau fan and its elimination method） 谈矿用局扇噪音及消除方法(Talking about the noise of mine bureau fan and its elimination method) Talk about the noise of local fan and eliminating method Author: admin source: the station of finishing hits: 262 update time: 2008-10-24 Local fan is one of the main noise source of mine, its value is often up to 100 ~ 110dB (A), greatly exceeded the national regulations of noise standard. Therefore, noise reduction is not only to protect the health of workers underground, but also the effective way to improve the working environment and improve production efficiency. A local fan noise and its direction The fan noise is mainly composed of air vortex, blade rotation and mechanical vibrations. Air flow into the rotating blade when will produce vortex in the round leaves. With the blade rotation, and eliminate vortex periodically, and a vortex sound. The frequency of vortex blade change gradually along the radius direction, vortex sound spectrum is a continuous spectrum. At the same time, the air into the fan rotation, not only the formation of pulsating pressure in the blade, but also occurred in air combat leaf phenomenon, a rotary sound. Merry voice and the voice of vortex rotation is generally referred to as aerodynamic noise. The fan and the mechanical noise is mainly caused by the unbalance, the fan rotor bearing installation, bad individual parts of the vibration and fault reasons of casing. In mechanical noise, a voice plays a major role, shell voice may be due to the formation of the pressure fluctuation in the case of forced vibration. Compared to air dynamic noise and mechanical noise and aerodynamic noise is the main. Therefore, the silencing of local fan is mainly to eliminate the fan aerodynamic noise. The fan aerodynamic noise level and fan type, size, shape and number of leaves, the number of revolutions per minute, the air flow velocity and so on. If the fan is not the right size, the fan is not in operation, the maximum efficiency under high speed, uneven air flow can cause the noise to increase. The fan noise is not occurred in all directions is uniformly radiation, it is like a hemispherical noise source, the fan inlet and outlet out of both sides and the fan frequency noise spectrum is basically the same. So, in order to eliminate the noise, people must be in the fan air inlet and an air outlet, a silencer or sound insulation measures at the same time. Two, the effective use of acoustic materials, reduce the fan noise In 60s, the resistive muffler some mines in China used plant fiber, glass fiber, foam for sound-absorbing material making fan. Today, in addition to some units continue to use these materials for silencing, some units of the micro perforated panel control fan noise. Micro perforated plate using sound waves become obsolete, air friction back and forth in the hole and energy consumption. So the sound-absorbing material can absorb energy, but also because of porous materials. Sound waves can cause vibration into the pore air in the pore and fine fiber materials, due to friction and viscous resistance, so that a considerable part of the sound energy into heat absorbed. Therefore, more and more loose material, hole, and the surface is full of pores, between the hole and the hole is connected with each other, in order to smooth through the acoustic material, the silencing effect is better to attract material. Three, improve the performance of equipment, reduce the fan noise Fan 1. developed large wind pressure and high efficiency and low noise. The ventilator used in coal mine main fan, auxiliary fan and fan 3, while the local fan is the most widely used, the largest number of a kind of ventilation equipment. There are about 50 thousand units in operation, the annual power consumption for the billions of. So the development of fan pressure, high efficiency, low noise, small volume and light weight is very meaningful. The successful development of Mitsui three pool factory "silent on the fan" and "low noise type mixed flow fan two fan, they sound-absorbing structure is easy to replace, can make the fan running in low noise long range. The successful development of Shenyang air blower factory BKJ66-1No4.6 new mine local fan with meridian acceleration, the highest efficiency reached 92%, and the noise area than the old fan to reduce 6bB (A) above. 2. development of small ventilation resistance, good silencing effect. If the fan total at a location operation, then soundproof cover volume to 16dB fan, ordinary steel plate (thickness 3mm) small noise is lldB noise. However, underground local fan ventilation equipment are often moving, which brings difficulties for the development of local fan muffler. First of all, in order to achieve a silencer, the total length of the fan with the muffler with before and after 2-3m, the weight is heavy, so the miners would rather endure the effects of high noise, would often carry this huge monster. Besides, underground space is limited, the unit length of 2~3m silencing also bring inconvenience to production. Therefore, small volume and light weight, although the volume or a little, a little, but very easy to remove the muffler, the workers will be welcome. 3. strengthen the ventilation pipeline noise reduction measures We should strengthen the research of noise characteristics at the same time as ventilation equipment, including air duct, the rational use of it must be further studied. The ventilation pipe generally have a sound vibration, it is because the fan and the motor, and the flow movement caused by pipeline. In order to reduce the noise, should flanges in the pipeline joints connecting add soft rubber or canvas. In order to reduce the radiation noise of the pipe wall, available damping material (asphalt damping paste, asphalt, and plaster) outer surface coated metal pipe wall. And also, the choice of ventilation parameters reasonably, so that the fan operates at maximum efficiency, ensure the stability of air flow, in order to create a good working environment.