Unlike other products, a fan typically has a service life of several years or even over a decade, and its price varies. Therefore, when choosing a fan, we must select one that is suitable and has a high cost-performance ratio. Today, let’s learn about the key points for selecting a fan. First, based on the two basic parameters of the required fan – air volume and air pressure, determine the model and number of the fan, as well as the required power through the performance table (all fan product manuals have relevant data). At this point, there may be more than one product that meets the requirements; we then combine the purpose of the fan, process requirements, and operating conditions (usage environment) to select the type, model, structure, and material of the fan to meet the required working conditions. We strive to make the rated flow and rated pressure of the fan as close as possible to the flow and pressure required by the process, so that the operating point of the fan is close to the efficient zone of the fan’s characteristics. The specific principles are as follows:
Before selecting a fan, one should familiarize themselves with the production and quality of ventilation equipment in China, including the types, specifications of the produced fans, and the specific uses of various products. They should also understand the current market situation of fans in China.
② Depending on the physical and chemical properties of the gas being conveyed by the ventilator, select a ventilator suitable for the specific purpose. For example, if conveying gases that are explosive or flammable, a dust-proof ventilator should be chosen, and the required explosion-proof level of the fan should be determined; if it is for dust removal or conveying coal powder, a dust removal or coal powder ventilator should be selected; if it is for conveying corrosive gases, a corrosion-resistant ventilator should be chosen, and the material for corrosion resistance (such as fiberglass reinforced plastic or PP) should be determined; if it is working in a high-temperature environment or conveying high-temperature gases, a high-temperature ventilator should be selected, and the environmental temperature and the temperature of the conveyed gas should be understood.
③ If there are more than two types of ventilators available on the performance chart, the one with higher efficiency, smaller size and wider adjustment range should be given priority. Of course, you can also compare in terms of cost-effectiveness and make a decision by weighing the pros and cons.
④ If the diameter of the selected fan impeller is much larger than that of the original fan impeller, in order to utilize the original motor shaft, bearings, and supports, it is necessary to calculate the motor startup time, the strength of the original fan components, and the critical rotational speed of the shaft.
⑤ When selecting a centrifugal fan, if the motor power it is equipped with is less than or equal to 75KW, a valve solely for starting purposes may not be installed. When choosing a centrifugal boiler exhaust fan to discharge hot flue gas or air, a valve for starting should be provided to prevent overload during cold operation.
⑥ For ventilation systems with noise requirements, the choice should start with ventilators that have high efficiency and low rotational speed of the impeller, and operate at their maximum efficiency point. Corresponding noise reduction and vibration reduction measures should also be taken based on the way the noise and vibration generated by the ventilation system propagate. The vibration reduction measures for ventilators and motors can generally be achieved through vibration reduction foundations, and different vibration reduction equipment can be selected depending on the installation method of the ventilators.
⑦ When selecting a ventilator, it is advisable to avoid using the ventilators in parallel or series operation. If such operation is unavoidable, it is recommended to choose ventilators of the same model and with the same performance to work in combination. When using series connection, there should be certain pipeline connections between the first and second stages of the ventilators.
