What Are The Causes And Solutions for Excessive Ventilation Noise in Fume Hoods?

Reason

Fan issue: The fan is one of the main sources of noise generated by fume hoods. If the quality of the fan itself is poor, it will generate a considerable amount of noise during operation. In addition, after long-term use of the fan, the bearings may wear out and rub against the rollers, generating noise. The fan blades may also operate unstably due to bending deformation or damage, thereby generating noise.

Pipe vibration: The vibration of ventilation ducts can also cause noise. When the fan is running, if the pipe is not fixed firmly or the pipe material is too thin, vibration is likely to occur. Moreover, if the diameter of the ventilation duct is too small, it may cause resonance, thereby triggering noise. In addition, the thickness of the exhaust pipe also affects the ventilation noise. Thinner pipes tend to produce relatively louder noise during ventilation.

Cabinet structure resonance: If the design of a fume hood is unreasonable, the material and structure of its cabinet may resonate with the fan, thereby increasing the noise.

Lack of noise reduction measures: If the fume hood does not have proper noise reduction measures, such as not installing a muffler on the pipe at the fan outlet or not placing a shock-absorbing pad under the fan, it will lead to excessive noise.

"Repair

Fan maintenance and replacement: For the issue of worn fan bearings, it is necessary to replace the bearings and apply lubricating oil. If the fan blades are bent, deformed or damaged, they need to be replaced. If the fan motor malfunctions, it also needs to be replaced in a timely manner. When choosing a fan, one should try to select products with guaranteed quality or ask the fume hood manufacturer to recommend purchasing a suitable fan.

Pipeline treatment: Check the fixation of the ventilation ducts to ensure they are firmly fixed and avoid vibration. For the problem of too small a pipe diameter, it is advisable to consider replacing it with a pipe of a larger diameter. At the same time, it is advisable to choose thicker exhaust ducts. Generally, pipes with diameters of 350 or 400 are preferred. This not only reduces noise but also provides better ventilation than thin pipes.

Cabinet structure optimization: If there is a problem of cabinet structure resonance in the fume hood, the cabinet structure can be optimized in design by adjusting the material or structure of the cabinet to avoid resonance with the fan.

Add noise reduction measures: Install a muffler on the pipe at the fan outlet. The muffler is made of porous sound-absorbing material and can effectively reduce noise. Place shock-absorbing pads under the fan, make the fan base into a shock-absorbing base, or add shock absorbers at the bottom of the equipment to prevent direct contact between the equipment and the ground from generating noise. In addition, when conditions permit, a frequency conversion system can be installed to reduce noise by controlling the wind speed of the fan.