What are the methods to reduce the noise of new fans?

1. Noise generated by fresh air when the main engine fan is running and noise generated by vibration of the main engine body.

1. Fresh air host noise: Select a host with acceptable noise.

For example, if you buy a tractor and expect the whole system to be transformed into an advanced silent car, even if it is finally realized, it must be very expensive, right?

As we all know, the nominal noise value of the same brand and different models of products with the same air volume (different purification capacity) is different (but this noise value refers to the noise measured in the anechoic room, about 1.5 meters below the fuselage). After the actual installation, due to the background noise and the refraction and reflection of sound waves in the room, the measured value is likely to be larger than the nominal value, and there are more complicated details, which are not described much.

After hearing what Bian Xiao said, some people will have doubts: If the requirement of purifying first is acceptable, can we buy something with low noise?

According to Bian Xiao, viewing the parameters is only the first step in the selection. Even if the manufacturer's parameters are realistic, there is no virtual standard, but the high frequency and low frequency bring different feelings to people, while the vibration and other indicators are not quantified, but they will be reflected in actual use. In this respect, we only need to look at the actual use of word-of-mouth of various models and the comparative experience of trial operation of physical stores.

In fact, no matter how the equipment is selected, there is always noise, which is nothing more than a quality problem, so the design, construction and debugging of fresh air system are needed to deal with it. The main idea of noise reduction measures for fresh air main engine is isolation (relatively basic, put the main engine in a position that is not so sensitive to noise, such as bathroom, kitchen and balcony, not to mention), and leave the noise and vibration near the machine and don't conduct it out.

2. Noise transmitted through the air.

The simple understanding is to isolate with materials with good sound insulation effect. If the effect in the ceiling is not good enough, sound-absorbing materials can be attached if the indoor surface conditions permit.

Here, we should add something that is not mentioned in the materials. As mentioned earlier, the equipment may vibrate, so it is very particular to install the derrick of the main engine. In theory, it is best to use shock-absorbing suspenders, but its price is several times that of ordinary suspenders. In reality, if consumers don't understand and ask for it without discussing the price, the installation company will never take the initiative to give it to you.

3. Pipes for connecting machines.

Silencers try to isolate noise transmitted through pipes, while flexible pipes isolate vibration transmitted by pipes. Is it easy for Bian Xiao to say this?

Secondly, aiming at the impact and friction of return air on pipes and air outlets.

The influence mainly occurs when the air volume changes. The more elbows there are, the greater the wind resistance is, and the more obvious the situation is. Friction, as long as there is airflow, will happen, and will soon move with the wind. The greater the wind speed, the louder the noise will be. . . Therefore, for HVAC designers, different pipe diameters will correspond to an "economic velocity" range. If it is simpler, the main pipe flow is 3 ~ 5m/s and the branch pipe flow is 2 ~ 2.5m/s. Then, when the amount of air to be transported in the pipeline is determined, according to the economic flow above, it is obvious how much the pipeline actually needs. However, some schemes blindly reduce the pipe diameter in order to make the opening on the beam smaller, which will either increase the pressure loss and reduce the air volume, or make the system produce more noise (and then helplessly ask what to do if the air volume is insufficient and the noise is too high).

Therefore, the configuration of pipe diameter (and hydraulic balance) is the basis of ensuring air volume and noise. If we don't deal with the noise on this basis, we just cover up the mistakes (not necessarily correct, and the air volume is not necessarily correct).

In the actual installation project, the number of household machines is generally 250,350. Under normal circumstances, the noise of DC motor is much less than that of AC motor, so it is recommended to look at the motor type more when selecting the machine (although success requires 1% talent and 99% effort, if there is no talent, no amount of effort will be in vain, so it is better to have good equipment). Secondly, it would be better if the fan impeller is balanced. There is basically no vibration. If there is vibration, it is only a matter of time. The noise can only be said to be getting louder and louder, and it has not fundamentally solved the problem. After a long time, you should reserve the top when changing the machine. Finally, regarding the choice of silencers, many silencers are bonded with egg cotton, and glue and inferior egg cotton contain more harmful gases to volatilize. Don't drive away pm2.5, it will lead to more serious odor pollution. Finally, if the muffler's egg cotton is inferior, it will take time.