Centrifugal fan is an indispensable equipment in industrial production, widely used in ventilation, dust removal, material transportation, air conditioning system and many other fields. However, in the face of complex working conditions and diverse fan models, how to choose the right centrifugal fan is a key issue. This article will start from the actual application, for your detailed analysis of how to choose the right centrifugal fan according to the working conditions.
First, clear working conditions demand: accurate positioning is the key
Centrifugal fan selection of the first step is to clarify the demand for working conditions, this step determines whether the fan can meet the requirements of the actual application. The following are a few aspects to focus on:
(1) Wind volume and wind pressure
Wind volume and wind pressure are the basic parameters of centrifugal fan selection. Air volume is the volume of gas conveyed by the fan per hour, usually expressed in cubic meters per hour (m³/h); wind pressure is the ability of the fan to overcome the resistance of the system, expressed in Pascal (Pa) or millimeter water column (mmH₂O). In practice, the required air volume and air pressure need to be calculated according to the design requirements of the ventilation system or process demands. For example, in a ventilation system, the air volume needs to meet the requirements of indoor air replacement; while in a dust removal system, the air volume needs to be determined according to the amount of dust generated and the transportation distance.
(2) The nature of the gas
The nature of the gas also has an important impact on the fan selection. Gas temperature, humidity, density, whether it contains corrosive or particulate matter, etc. need to be considered. For example, if the gas temperature is high, you need to choose high temperature resistant fan, in order to prevent fan parts due to high temperature and damage; if the gas contains corrosive components, such as acidic or alkaline gases, you need to choose the anti-corrosion performance of the fan material, such as stainless steel or glass fiber reinforced plastic, etc.. In addition, the density of the gas will also affect the fan selection, because the density of different gases in the same air volume, the required air pressure will be different.
(3) system resistance
system resistance is a factor easily overlooked in fan selection. System resistance includes piping resistance, equipment resistance, elbow resistance and so on. In practice, the total resistance of the system needs to be calculated according to the piping layout of the ventilation system, piping length, piping diameter, equipment type and other factors. Only by accurately calculating the system resistance can we ensure that the fan has enough air pressure to overcome the resistance and realize efficient operation. If the fan does not have enough air pressure to overcome the system resistance, it may result in insufficient airflow and affect the normal operation of the system.
Second, choose the type of fan: different according to needs
Centrifugal fan has a variety of types, each type has its special performance characteristics. Choosing the right type of fan can ensure that the fan plays a good performance in the actual application. Below are a few common fan types and their application scenarios:
(1) Single suction and double suction fans
Single suction fan and double suction fan are two basic forms of centrifugal fan. Single suction fan impeller only one side of the air intake, applicable to the occasion of smaller air volume; double suction fan impeller both sides at the same time into the air, applicable to the occasion of larger air volume. When choosing, you need to determine the type of fan according to the actual required air volume. For example, in small ventilation systems, single suction fan can usually meet the demand; while in large industrial ventilation systems, double suction fan is more appropriate.
(2) Low noise and high flow fans
In some places with high ambient noise requirements, such as hospitals, schools, office buildings, etc., low-noise fans need to be selected. Low noise fan through the optimization of the impeller design, the use of sound insulation materials, etc., to reduce the operation of the noise generated, can effectively reduce the interference of the surrounding environment. High-flow fans, on the other hand, are suitable for scenarios that require a large amount of air transportation, such as the ventilation of large workshops, material transportation and so on. High-flow fans usually have larger impeller diameters and higher rotational speeds, and are able to provide larger air volumes.
(3) Installation form
The installation form of centrifugal fan will also affect its selection. Common installation forms are horizontal installation and vertical installation. Horizontally mounted fan covers a large area, but installation and maintenance is relatively convenient, suitable for use in space-allowed occasions; vertically mounted fan covers a small area, but installation and maintenance requires certain technical requirements, suitable for use in space-limited occasions. When choosing the form of installation, it is necessary to determine according to the space conditions and installation requirements of the site.
Centrifugal fans
III. Calculations and selection: data-driven decision-making
The selection of centrifugal fans needs to be based on accurate calculations and performance curve analysis. Below are a few steps to focus on during the selection process:
(1) Parameter conversion
As the performance parameters of the fan is usually given in the standard state, and the actual working conditions of the gas conditions may be different from the standard state, so it is necessary to convert the working conditions of the air volume, wind pressure and other parameters to the standard state. The standard state refers to the environmental conditions where the temperature is 20℃, the pressure is 1 atmosphere and the relative humidity is 60%. Through the conversion, the actual working condition parameters can be compared with the fan performance curve, so as to select the appropriate fan model.
(2) Specific rotation calculation
Specific rotation is an important reference index for centrifugal fan selection. Specific rotation is a dimensionless parameter, which reflects the impeller shape and flow characteristics of the fan. The larger the specific rotation number, the larger the flow of the fan, but the wind pressure is relatively low; the smaller the specific rotation number, the higher the wind pressure of the fan, but the flow is relatively small. By calculating the specific revolution, you can initially determine whether the model of the fan is suitable for the requirements of the working conditions. For example, for occasions that require high wind pressure, a fan with a small specific revolution should be selected; for occasions that require large flow, a fan with a large specific revolution should be selected.
(3) Performance curve analysis
Fan performance curve is an important basis for selection. Performance curve includes causal performance curve and non-causal performance curve, by analyzing the performance curve, you can determine the efficiency of the fan in different working conditions, power, flow and wind pressure and other parameters. When selecting the fan, the fan should be operated in the high efficiency zone as much as possible in order to improve the operating efficiency and reduce energy consumption. At the same time, it is also necessary to pay attention to whether the operating conditions of the fan are within the effective range of the performance curve, so as to avoid running the fan in the inefficient or unstable area.
Fourth, consider other factors: details determine success or failure
In addition to the above core parameters and selection steps, there are a number of detailed factors will also affect the selection and use of the fan:
(1) Energy saving and efficiency
With the rising cost of energy, selecting high-efficiency, low-energy fans can significantly reduce operating costs. Under the premise of meeting the demand of working conditions, fans with higher energy efficiency ratings should be selected as far as possible. High-efficiency fans usually improve their operating efficiency and reduce energy consumption by optimizing impeller design and adopting excellent motor technology.
(2) Noise and vibration
The noise and vibration generated during the operation of the fan will not only affect the service life of the equipment, but may also cause interference to the surrounding environment. Therefore, try to choose low noise and low vibration fans. Low noise fan through the optimization of impeller design, the use of sound insulation materials, etc., to reduce the noise generated during operation; low vibration fan through the optimization of structural design, the use of vibration damping devices, etc., to reduce the vibration of the operation. In some occasions with high environmental requirements, such as hospitals, schools, etc., the selection of low-noise, low-vibration fans is particularly important.
Centrifugal fan
Selecting the right centrifugal fan is a systematic project, which requires comprehensive consideration of the demand for working conditions, fan type, calculation and selection, other factors and professional consultation. By clarifying the demand for working conditions, choosing the right type of fan, accurately calculating and analyzing the performance curve, and paying attention to detailed factors, you can ensure the accuracy and reliability of fan selection. We hope that the introduction of this article can provide you with a useful reference to help you quickly find the right centrifugal fan. #centrifugalfan
