Safety and noise of large industrial fans

2020-09-04 14:18:57 浙江马尔风机有限公司 Viewd 151

When choosing and purchasing a large industrial fan, users will inevitably feel confused and do not know which one is better. In addition to meeting performance requirements, the most important thing for a good industrial fan is safety and noise. The first is the five safety standards for large industrial fans.


1. Check whether the motor head and the whole machine will vibrate in the low-speed gear and medium-speed gear, especially when the high-speed gear is rotating.


2. After a long time of high-speed rotation (at least 1 hour later), feel the heat generated by the front shell of the industrial large fan motor with your hands or other appliances. If you feel it is very hot, it means that the heat dissipation performance of the industrial large fan motor is not good.


3. Look at the speed, power, air volume, noise and other parameters (the speed, power, air volume and noise of large industrial fans are proportional, that is, the higher the speed of industrial large fans, the greater the power, the greater the air volume, and the greater the noise. The better the local ventilation and cooling effect).


4. Check if there is an intermittent pause when the swing head swings at high speed, and whether the swing head is not in place.


5. The big palm industrial fan has designed a new tenon-and-mortise structure connection method, which has a real anti-collision function.


Secondly, we have to look at the noise of large industrial fans. What is the source of the noise?


1. Vibration. If the rotor of a large industrial fan rotates, the physical center of mass of the rotor and the center of inertia of the shaft are not on the same axis, which will cause the rotor to be unbalanced. The close distance between the physical center of mass of the rotor and the center of inertia of the rotating shaft is called For the eccentricity, force will be generated when the rotor rotates. Because centrifugal force acts on the shaft support, vibration will be formed. The vibration will be transmitted from the basic path to all parts of the machine.


2. Wind noise. When large industrial fans are used, the blades periodically bear the impulse power of uneven flow at the outlet, which produces noise; on the other hand, the pressure distribution on the blade itself and above the blade is uneven, which is easy to interfere when rotating Surrounding gas and components; In addition, when the airflow passes through the blade, the turbulent adhesion layer, vortex and vortex are separated, which causes fluctuations in the pressure distribution of the blade and generates vortex noise. The noise caused by these three reasons can be collectively called cut wind noise. In general, fans with large air volume and high wind pressure also have a large cut wind noise.


3. Different sounds, the sound of the wind is just a simple wind, and different sounds are different. When the industrial fan is running, if there are other sounds besides the wind, you can judge that the industrial fan has different sounds. Abnormal noise may be caused by foreign matter or deformation in the bearing, improper assembly and collision of the motor winding, or uneven winding, which may cause the motor winding to loosen and produce abnormal sound. The service life of large industrial fans refers to the normal working hours of radiator products. The service life of large industrial fans can generally reach tens of thousands of hours because of the high quality of the products.


Industrial large fan noise refers to the size of the noise when the fan is working, which is affected by many factors and is measured in decibels. When measuring the noise of a large industrial fan, it needs to be carried out in a silent room with a noise less than 17dB and one meter away from the fan, and aligned with the fan inlet along the fan axis, and the A-weighting method is used to measure the noise of the fan.


The spectral characteristics of the noise of industrial large fans are also very important, so it is also necessary to record the frequency distribution of the fan's noise with a spectrum analyzer. Generally speaking, the noise of the fan should be as small as possible, and there is no abnormal sound. Fan noise is related to friction and airflow. The higher the fan speed, the greater the air volume, and the greater the noise. The vibration of the fan itself is also a factor that cannot be ignored. Of course, the vibration of the high-quality fan itself will be small, but the first two are insurmountable. To solve this problem, we can try to use a larger fan. In the case of the same air volume, the operating noise of the low-speed large fan is smaller than that of the high-speed small fan.