In many fields such as industrial production and building ventilation systems, fans are widely used equipment. There are various types of fans, including axial flow fans, cross-flow fans, centrifugal fans, etc. Among them, centrifugal fans are recognized and highly praised by people due to their many advantages. However, when fans are in operation, noise will inevitably be generated, and the noise has different classifications in terms of sound levels and pressures. Having a full understanding of the specific classification rules of noise sound levels and pressures plays a crucial role in our more scientific use and proper maintenance of fans, and it also helps to improve production efficiency and create a comfortable using environment.
The noise sound level, as an important reference indicator for measuring the magnitude of the noise generated by centrifugal fans, has a unit of decibel (dB), which is a relative measurement unit based on the hearing threshold.
Under normal circumstances, the range that human hearing can perceive is between 20Hz and 20kHz. The higher the decibel value of the noise, the louder the noise. When planning and formulating noise protection-related measures, according to the level of the noise sound level, it can usually be divided into the following categories:
- Below 40 decibels: This interval belongs to the category of extremely quiet. The noise within this range is hardly perceptible, just like in a quiet indoor sleeping environment where the external sound is minimal and will not interfere with people’s rest.
- 40 – 60 decibels: It belongs to the level of slight noise. In daily life, people often encounter this kind of noise. For example, the sound when people whisper or the relatively slight sound generated by some small machines in operation is within this range, and it basically will not bring obvious discomfort to people.
- 60 – 80 decibels: This interval represents noisy sounds. The noise generated by some large-power machines that make a lot of noise during operation and the noisy sounds that people hear in the traffic environment, such as the roar of the engine when a car is running on the road, mostly fall within this sound level range, which will make people clearly feel that the environment is rather noisy.
- 80 – 100 decibels: It belongs to a very noisy situation. In such a noisy environment, people will often feel strong discomfort. For example, the huge roar generated when a helicopter is flying in the air is within this range. If people stay in such an environment for a long time, their mood and state will be greatly affected.
- Above 100 decibels: The noise in this range is quite dangerous and is very likely to cause hearing damage. In many high-noise-risk working environments, the noise sound level often exceeds 100 decibels. If workers are exposed to such a high-intensity noise environment for a long time, their hearing will gradually be damaged, and in severe cases, it may even lead to deafness, which is extremely harmful.
The pressure of a centrifugal fan specifically refers to the pressure generated during the process of the fan promoting the flow of gas. It is one of the key indicators for evaluating the strength of the fan’s function and the quality of its performance, and it can mainly be divided into the following two important indicators:
- Static pressure: Static pressure refers to the pressure generated during the process of the fan sucking in air or other gases, and its unit is Pascal (Pa). It reflects the fan’s ability to maintain a certain pressure at the air inlet and plays a fundamental role in ensuring the smooth entry of gas into the fan.
- Dynamic pressure: Dynamic pressure represents the pressure generated when the fan discharges air or other gases, and its unit is also Pascal (Pa). Dynamic pressure reflects the kinetic energy given to the gas by the fan and is related to aspects such as the speed and force of gas discharge.
For users of centrifugal fans, it is crucial to ensure that the pressure during the operation of the fan is within a reasonable and correct range. Because the level of the pressure value will directly have a significant impact on the operating efficiency of the fan. Once the pressure is too low, the fan will have difficulty effectively realizing functions such as air transportation and purification; on the contrary, if the pressure is too high, in addition to causing abnormal vibration of the fan itself, it is also very likely to cause a series of other problems such as increased noise, which will then affect the service life of the fan and the comfort of the entire using environment.
In conclusion, understanding the classification of noise sound levels and pressures of centrifugal fans has important significance that cannot be ignored, whether it is for ensuring the normal and efficient operation of the fan, maintaining the health of users, or creating a good surrounding environment.
