Axial flow fan accidents are divided into three types of accidents according to the degree of impact, of which the first type of accident is the most serious. The third type of accident means that there is a safety hazard in the axial flow fan.
The specific categories are:
The first category is the serious failure of the fan, which causes the entire thermal power unit to fail to operate normally, which seriously affects production work;
The second category is that the working efficiency of the axial flow fan decreases, but it does not cause the thermal power unit to stop running, but it affects the working efficiency of the thermal power unit;
In the third category, there is a small failure or hidden trouble of the axial fan, which causes a slight decrease in the operating efficiency of the axial fan, but does not affect the normal operation of the thermal power unit.
There are many common faults of axial fans, because axial fans have been in a high-load working environment, so there are many possible faults.
Rotor fault, which is a common fault in axial flow fans, specific faults include rotor bending, running vibration, or problems in the connection between the rotor and the impeller, etc., causing the rotor shaft to idling and the impeller and rotor to slip.
Blade failure, the blade has been subjected to great force during long-term work, so it is prone to cracks and fracture accidents. At the same time, this kind of failure is difficult to check. Because the axial flow fan is always in a high-speed operation state, it cannot be predicted by any method. Impeller failure. Therefore, impeller breakage is the most common production accident of axial flow fans.
Damage to the fan bearing will cause the stator casing to lock the rotor, which will have a huge impact on the fixing of the stator casing, causing the axial fan to fall off as a whole. When the circuit is too large, the copper wire in the circuit will burn out the stator or rotor, causing huge damage to the motor, and the lack of grease will cause dry grinding of the components in the fan, which will eventually lock the bearings and rotors. Therefore, attention should be paid to adding grease in daily maintenance.
1. The quality of the axial fan itself
First of all, the axial flow fan may be the first, because there are certain safety hazards in the design, mechanical elements are ignored in the design, resulting in the failure of the axial flow fan, or because of cutting corners in the production, resulting in low work efficiency, the stability is not good.
Second, the expansion coefficient of the gas is forgotten in the design, and the gas application characteristics are not understood in detail.
Third, the blades are not routinely maintained. In the production of the enterprise, the importance of production is emphasized and the importance of maintenance is despised. Or the quality of the leaves is not up to standard.
Fourth, the quality of the grease is poor, or the anti-sublimation properties are poor, which causes the lubrication quality of the axial fan to become extremely poor after a period of operation.
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. Operation and maintenance
Axial fans work under stall conditions for a long time, the amplitude of airflow pressure pulsation increases significantly, and the blade resonance is damaged. Do not start and run parallel to the requirements of the fan characteristics, and the fan operating conditions do not match the system characteristics. The low efficiency of electrostatic precipitator or electrostatic precipitator leads to high dust concentration at the fan inlet. When two fans are running in parallel, the operating points of the two are quite different. Axial fan surge protection failure, no regular maintenance or poor maintenance.
The shaft system is unbalanced or poorly connected, resulting in large vibration of the fan and easy damage to bearings and couplings. The installation error of the actuator is large, and the local indication value is inconsistent with the feedback value of the control room, resulting in inaccurate operation.
4. Fan selection and system design
Improper selection of axial flow fans may cause 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 piping system may cause fatigue and damage to the relevant components of the fan rotor.