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Axial Flow Impeller Work Reliability
Jun 14, 2017

Fans are widely used in many industrial processes and are an important auxiliary machinery for industrial production. Axial Flow Impellers are widely used because of their high energy efficiency. But in recent years because of Axial Flow Impeller caused by the production accidents are often occur, especially the power plant Axial Flow Impeller, often failure, although rarely cause casualties, but for the power plant caused by downtime, and damage to the turbine equipment, resulting in Huge economic loss. Therefore, in such a case, it is very important to enhance the reliability of the Axial Flow Impeller operation and improve the working efficiency of the Axial Flow Impeller.

Power station fan reliability concept

Before the 1990s, China's large power plants (125MW and above) boiler fan caused by unplanned downtime and unplanned downhill more frequent, according to statistics, in 125MW, 200MW, 300MW and 600MW units, according to the loss of the equivalent power plant downtime Count, send, induced draft fan are ranked in the top 10 influencing factors, and the gap between developed countries. After the 1990s, several major power plant fan factory equipment quality improved rapidly, for the actual situation of China's power plants, the introduction of foreign advanced technology, so that the power station fan, especially the adjustable blade Axial Flow Impeller reliability has been improved.

Factors Affecting the Reliability of Axial Flow Fan

2.1 Power station fan accident classification

The accident of the Axial Flow Impeller is classified into three types of accidents according to the degree of influence, among which the first type of accident is the most serious. The third category of accidents on behalf of the Axial Flow Impeller there are security risks. Specific classification: the first category, a serious fan failure, resulting in the entire thermal power units can not run properly. Which has affected the work efficiency of the thermal power unit. The third type, the Axial Flow Impeller has a small fault or a hidden trouble, resulting in the shaft The operating efficiency of the flow fan is slightly reduced, but it does not affect the normal operation of the thermal power unit.

2.2 Common faults of Axial Flow Impellers

Axial Flow Impellers have a lot of common faults, because the Axial Flow Impeller has been in a high load of the working environment, so there may be a lot of failure. Rotor failure, which is the fan more common fault, the specific failure, including the rotor bending, running vibration, or rotor and impeller connection problems, resulting in rotor shaft idling, impeller and rotor slippage phenomenon. Leaf blade failure, the blade in the work of a long time by a great force, so easy to crack cracks and fracture accidents, and this failure is also difficult to check, because the Axial Flow Impeller is always in high-speed operation, so can not use what way to predict Impeller failure. So the impeller fracture is the most common Axial Flow Impeller production accidents? Damage to the fan bearing can cause the stator shell to hold the rotor, the stator shell fixed to produce a huge impact, resulting in the overall collapse of the Axial Flow Impeller. When the circuit circuit is too large, the wire in the copper wire to produce thermal effects will stator or rotor burned, causing great damage to the motor, the lack of grease in the fan components appear dry grinding, the final bearing, rotor and other lock. So in the daily maintenance should pay attention to increase the grease.

2.3 causes of Axial Flow Impeller failure

2.3.1 The problem of the quality of the Axial Flow Impeller itself

First, the Axial Flow Impeller may be the first, because there is a certain design in the security risks, in the design of mechanical elements are ignored, resulting in Axial Flow Impeller failure, or because in the production of cutting corners, resulting in work efficiency is not high , Stability is not good. Second, in the design forgot to consider the expansion coefficient of gas, and gas use characteristics without a detailed understanding. Third, the leaves are not carried out daily maintenance, production, attention to production, contempt for the importance of maintenance. Or the quality of the leaves is not qualified. Fourth, the quality of the grease is poor, or the resistance to sublimation is poor, resulting in axial flow fan running for some time, the lubrication quality becomes very poor. Fifth, the corresponding fault detection module is damaged, there is no way to reflect the normal operation of the fan in a timely manner.

2.3.2 operation, maintenance aspects

Axial flow fan long-term work in the stall conditions, air pressure pulsating amplitude increased significantly, leaf resonance damage. Do not follow the fan characteristics required to start and the car, fan operating conditions and system characteristics do not match. Do not throw electricity or dust removal efficiency is low, resulting in high dust inlet density. When the two fans are running side by side, the working points of the two are quite different. Axial Flow Impeller surge protection failure. No regular maintenance or poor maintenance.

2.3.3 installation aspects

Shaft imbalance or connection is not good, resulting in fan vibration, bearings, coupling easy to damage. The actuator installation error is large, the local indication value and the control room feedback value is inconsistent, resulting in the operation is not accurate.

2.3.4 fan selection and system design aspects

Improper selection of the fan caused the actual operating point of the fan in the unstable air flow area or close to or even into the stall area, and fan pipe system characteristics of unreasonable, can cause the fan rotor parts of the fatigue and damage.