Analysis and treatment of the problem of reduced efficiency of axial flow fans
1.There are many common faults of axial flow fans.
Because axial flow fans have been working in a high-load environment, there are many possible faults. Rotor failure is a common fault in fans. Specific faults include rotor bending, running vibration, or problems with the connection between the rotor and the impeller, which causes the rotor shaft to idle and the impeller and the rotor to slip. Blade failure. The blades are subjected to great forces during long-term work, so they are prone to coarse and fine cracks and fracture accidents. At the same time, this fault is difficult to check. Because the axial flow fan is always in a high-speed operation state, there is no way to predict the failure of the impeller. Is the impeller fracture the most common production accident of the axial flow fan? Damage to the fan bearing will cause the stator shell to lock the rotor, which will produce a huge impact force on the fixation of the stator shell and cause the overall detachment of the axial flow fan. When the circuit is too large, the copper wire in the circuit will produce a thermal effect to burn the stator or rotor, causing great damage to the motor. Insufficient grease causes dry grinding of the components in the fan, and eventually locks the bearings, rotors, etc. Therefore, pay attention to adding grease in daily maintenance.2.Causes of axial fan failure
2.3.1 The quality of the axial flow fan itself
First of all, the axial flow fan may be the first, because there are certain safety hazards in the design, and the mechanical elements in the design are ignored, resulting in the failure of the axial flow fan, or because of cutting corners in the production, resulting in low efficiency and poor stability. Second, the expansion coefficient of the gas was forgotten to be considered in the design, and there was no detailed understanding of the gas application characteristics. Third, the blades were not maintained on a daily basis. In the production of enterprises, production is emphasized and the importance of maintenance is underestimated. Or the quality of the blades is unqualified. Fourth, the quality of the grease is poor, or the anti-sublimation properties are poor, resulting in the axial flow fan After running for a period of time, the lubrication quality becomes extremely poor. Fifth, the corresponding fault detection module is damaged, and there is no way to reflect the normal working condition of the fan in time.
2.3.2 Operation and maintenance
The axial flow fan has been working under stall conditions for a long time, the airflow pressure pulsation amplitude has increased significantly, and the blade resonance has been damaged. The fan is not started and operated according to the fan characteristics, and the fan operating conditions do not match the system characteristics. No electrostatic precipitator or low electrostatic precipitator efficiency leads to high dust concentration at the fan inlet. When two fans are running in parallel, the operating points of the two fans are quite different. The surge protection of the axial flow fan fails. No regular maintenance or poor maintenance.
2.3.3 Installation
The shaft system is unbalanced or poorly connected, resulting in large fan vibration, easy damage to bearings and couplings. The actuator installation error is large, and the local indication value is inconsistent with the feedback value in the control room, resulting in inaccurate operation.
2.3.4 Fan selection and system design
Improper fan selection causes the actual operating point of the fan to be in the unstable airflow area or close to or even enter the stall area, and the unreasonable characteristics of the fan pipeline system can cause fatigue and damage to the relevant parts of the fan rotor.
The operation of the axial flow fan is related to the stability of the thermal power unit. Although it is an auxiliary equipment, the main unit cannot run for a long time without the heat dissipation of the axial flow fan. Therefore, the axial flow fan is extremely important in industrial production. In order to improve the working efficiency of the axial flow fan, the most direct way is to reduce the frequency of axial flow fan failures and improve the working reliability of the axial flow fan. It is necessary to first classify the axial flow fan failures, and then find out the causes of the axial flow fan failures, solve the problems through the causes, and adopt the method of connecting multiple groups in parallel. On the one hand, it increases the efficiency of cooling the industrial unit, and on the other hand, it is also convenient for maintenance and maintenance. Even if an axial flow fan fails, the system can still operate normally.
