Guide to Selecting Low-Noise Enclosed Centrifugal Fans

Guide to Selecting Low-Noise Enclosed Centrifugal Fans

There are many types of low-noise enclosed centrifugal fans, and selecting the appropriate model is crucial. Only by choosing the correct model can a low-noise enclosed centrifugal fan achieve maximum efficiency and, consequently, deliver optimal performance. So, how should one go about selecting the right model? To select a low-noise box-type centrifugal fan, you must first determine the gas flow rate, pressure, and density. These are the three key factors in the selection process. Density is the first and most important factor in the selection process. If the density is not specified, the density of the working gas must be calculated or converted based on the fan’s operating environment—such as altitude, local atmospheric pressure, operating temperature, and the standard density of the gas. Pressure is the second key factor in selecting a low-noise box-type centrifugal fan. Based on the given or calculated density under operating conditions, the pressure under those conditions is converted to the pressure of the low-noise box-type centrifugal fan under standard operating conditions. If the low-noise box-type centrifugal fan is equipped with an intake box or a silencer, their pressure losses must be taken into account. After calculation or estimation, the estimated loss is typically 100–300 Pa. Airflow is the third factor in the selection process. When the system requires the mass flow rate of the gas, this must be converted to the volumetric flow rate of the low-noise box-type centrifugal fan under standard conditions. When the system requires the volumetric flow rate of the gas, the volumetric flow rate of the low-noise box-type centrifugal fan under standard conditions is the same as that under operating conditions. The next step is to calculate the specific speed of the low-noise box-type centrifugal fan. Calculating the specific speed is a crucial step in the selection process for low-noise box-type centrifugal fans and serves as the primary basis for determining the appropriate model. By substituting the performance parameters and speed of the low-noise box-type centrifugal fan—converted to standard conditions—into the specific speed formula, different specific speeds can be obtained for different speeds. The primary specific speed forms the basis for single-suction low-noise box-type centrifugal fans, while the secondary specific speed forms the basis for double-suction low-noise box-type centrifugal fans.