Combating noise and vibration with fans
When operating fan systems, there are two types of noise: aerodynamic - from the vortices, runs away with a blade wheel by forming the air waves and mechanical vibrations arising from the fan and motor, as well as bearings and transmission.
Mechanical noise is closely related with the vibration. Reducing vibration of both the fan and its base at the same time reduces the mechanical noise.
Vibration fan installation is harmful not only to create noise. Caused by fluctuations in its building designs are often a hindrance to technological process, not to mention an unpleasant sensation in humans. For example, in the shops of the exact mechanics of PLI semiconductor manufacturing, as well as in laboratories is unacceptable even a slight vibration. In extreme cases, when the vibration of the fan is abnormally high, perhaps even the destruction of building structures.
The main cause of vibration fan - neotbalansirovannoe impeller. Unfortunately, this abnormality is sometimes observed and new fans. In the former work, especially cleaning the exposed fans, unbalancing the impeller - a phenomenon frequently.
Vibration of the impeller is most pronounced at high revs. Fan working "quietly", say at 600 rpm, can be quite intolerant with increasing speed up to 1000.
Installing the fan directly on the metallic structures or blocking, even when well-balanced wheel will inevitably cause the vibration of building elements of the building, the higher the number of wheel revolutions.
Typically, the installation of fans without any cushioning device is invalid.
Good shock absorbers - massive concrete slabs which are laid on the elastic lining or springs. Fan installation is attached to the plate, as freely lies on the overlap.
Sometimes installing the fan on the solid support - the only acceptable way. This occurs when you install the fan in the basements with waterproofing. In fact, at any other installation method necessary foundation bolts, ie, violation of the integrity of the waterproofing.
When installing the fan on the massive slabs should be borne in mind that the stove will be massively better.
Based on real data are advised to take the weight plate is 3-5 times greater than the weight is on the stove fan installation. Here we must take into account the type of fan, its size, speed, possibility of unbalancing the wheel, etc.
The thickness of the strips usually takes from 30 to 100 mm. Grommets are located in special pits provided for in the slab.
For the convenience of mounting fan installation panel thickness is taken within 200-300 mm.
The most common and reliable shock absorbers are vibration isolation base with spring shock absorbers.