The selection of fans Product performance and fan performance listed in the selection table are based on the performance of delivering air under standard conditions. Therefore, when the use condition is non-standard, the H4-72-12 centrifugal fan must convert the use performance into the performance under standard conditions according to the relationship in the table above, and then select according to the performance and selection table. （3） Treatment of excessive or insufficient flow During use, excessive or insufficient flow often occurs. There are many reasons for this phenomenon. If the flow is high and low during use, it is mainly because the resistance in the pipe network is high and low, or the fan works in a non working area. If it is gradually reduced after a long time during use, it is mainly due to pipe network blockage. After the fan is newly installed, the flow is too large or insufficient during the formal operation. The main reasons for this phenomenon are as follows: 1. The actual value of pipe network resistance is too different from the calculated value. In the general pipe network characteristic equation, H=KQ2, if the actual value K of K-resistance coefficient is less than the calculated value K, the flow will increase; If the actual value K is greater than the calculated value K, the flow decreases. See (b) below.

Among all kinds of mechanical and electrical equipment in all walks of life in China, the motors matched with fans account for about 60% of the installed capacity of national motors, and the power consumption accounts for about one-third of the total power generation in China. In particular, Wet electrostatic precipitator company Most fans have the phenomenon of pulling a cart from a horse during use. In addition, due to changes in production and technology, it is necessary to frequently adjust the gas flow, pressure, temperature, etc; Many units still adopt the backward way of adjusting the opening degree of the wind shield or valve to adjust the gas flow, pressure, temperature, etc. In fact, this is to meet the requirements of process and working conditions for gas flow regulation by artificially increasing resistance at the cost of wasting electric energy and money. This backward regulation mode not only wastes valuable energy, but also has poor regulation accuracy, which is difficult to meet the requirements of modern industrial production and services, and has serious negative effects. With the continuous improvement and development of frequency conversion technology in recent ten years. The performance of variable frequency speed regulation is becoming increasingly perfect, customized Wet electrostatic precipitator It has been widely used in AC speed regulation in different fields. It has brought considerable economic benefits to enterprises and promoted the automation process of industrial production.

When the bearing temperature of the fan is normal, it is ≤ 70 ℃. If it rises to 70 ℃, an alarm should (will) be given if there is an electric control. At this time, the reason should be found out. First, check whether the cooling water is normal? Is the bearing oil level normal? If the cause cannot be found for a while, the bearing temperature rises rapidly to 90 ℃, and if there is an electric control, the alarm and shutdown signal shall be sent again. Shiyan Wet electrostatic precipitator In the process of fan startup, shutdown or operation, if any abnormal phenomenon is found, it shall be checked immediately. If any small fault is found during the check, it shall be timely found out the cause and eliminated. In case of major fault (such as severe vibration, impact of fan, sharp rise of bearing temperature, etc.), stop the machine immediately for inspection. customized Wet electrostatic precipitator The lubricating oil (or grease) shall be renewed and replaced one month after the first operation of the fan. In addition to replacement after each overhaul, the lubricating oil (or grease) can be replaced once every 1~2 months under normal conditions, or according to the actual situation. Fans include fans, turbine blowers, roots blowers and turbine compressors, which are divided into 7 categories in detail, including centrifugal compressors, axial compressors, centrifugal blowers, roots blowers, centrifugal fans, axial fans and Ye's blowers

Preparations for fan installation. customized Wet electrostatic precipitator Before unpacking the fan, check whether the package is intact, whether the nameplate parameters of the fan meet the requirements, and whether all accompanying accessories are complete. Carefully check whether the fan is deformed or damaged during transportation, whether the fasteners are loose or fall off, and whether the impeller is scratched, and check all parts of the fan. Shiyan Wet electrostatic precipitator company If any abnormality is found, it shall be repaired before use. Use a 500V megger to measure the insulation resistance between the fan housing and the motor winding. The value should be greater than 0.5 megohm. Otherwise, the motor winding should be dried. The temperature during drying should not exceed 120 ℃. Prepare various materials, tools and sites required for fan installation.

（3） The main faults and causes of the fan may occur during the operation of the fan. For the faults generated, the causes must be quickly identified and solved in time to prevent accidents. Faults in the Operation of 4-72-12 Centrifugal Fan and the Causes Table Fault Name Causes Severe Vibration of Bearing Box 1. The fan shaft is different from the motor shaft, and the coupling is installed askew. 2. The casing or air inlet rubs with the impeller. 3. The foundation stiffness is not enough or firm. 4. Impeller rivet is loose or wheel disc is deformed. 5. The impeller shaft disk and shaft are loose, and the coupling bolt is movable. 6. The connection between casing and bracket, bearing box and bracket, bearing box and seat is loose. 7. The air inlet and outlet pipes of the fan are poorly installed, causing vibration. 8. The rotor is unbalanced. Bearing temperature rise is too high 1. The bearing box vibrates violently. 2. The lubricating grease is poor in quality, deteriorated or overfilled, or contains dust, sand, dirt and other impurities. 3. The tightening force of connecting bolts of bearing cover seat is too large or too small. 4. The shaft and rolling bearing are installed askew, and the front and rear bearings are not concentric. 5. The rolling bearing is damaged. The motor current is too high and the temperature rise is too high. 1. The throttle valve in the air inlet pipe is not closed tightly when driving. 2. The flow exceeds the specified value, or the air duct leaks. 3. The gas density conveyed by the fan is too high. 4. The input voltage of the motor is too low or the power supply is cut off individually. 5. The coupling is improperly connected, the leather ring is too tight or the gap is uneven. 6. Affected by the violent vibration of the bearing box. 7. Affected by deterioration or failure of parallel fans. When the belt slides down, the two pulleys are not in the same plane with each other. Belt runout The distance between two pulleys is too close or the belt is too long.