When the boiler fan is running, due to the negative pressure generated by the blower in the sound insulation room, a large amount of outdoor fresh air will automatically enter the sound insulation room.
First, heat exchange with the induced draft fan motor to cool it, and the Boiler Fan indoor temperature will be maintained at about 50 ℃. Then, what is the reason for the excessive temperature of the fan bearing?
1. The excessive temperature rise of the bearing of the boiler fan is likely to be caused by the violent vibration of the box. The shaft of boiler fan is Boiler Fan inclined, and the bearing is inclined in the bearing package, resulting in high temperature of fan bearing during operation.
The reason is that the installation and maintenance quality of the fan is not Boiler Fan high, and the bearing operates at the critical edge of the allowable adjustment angle.
2. Such problems will also be caused when the lubricant is of poor quality, deteriorated or contains impurities such as dust, sand and dirt, or the filling amount is insufficient, or the Boiler Fan tightening force of the connecting bolts of the bearing housing cover and seat is too large or too small;
3. The bearing package of boiler fan is not filled with specified grease according to the standard. Generally, the post personnel are worried that the bearing will be burned due to the lack of oil in the fan,
and the amount added during refueling is too much. At this time, the temperature continues to rise. After reaching a certain point (generally about 10 ~ 15 ℃ higher than the normal operating temperature), it will remain unchanged, and then gradually decrease.
4. The bearing of boiler fan is abnormal, resulting in bearing heating. The skew installation of shaft and rolling bearing, the non concentricity of front and rear bearings, the damage of fan rolling bearing or the bending of shaft are all one of the factors affecting the temperature of fan bearing.
Fault mechanism of bearing
1. Fault mechanism of bearing.
Bearings are common in most mechanical equipment, with high Boiler Fan utilization rate and high damage rate. Bearing has many advantages such as good starting performance, high reliability and convenient maintenance.
It is widely used in mechanical equipment. When the equipment is in the state of constant speed, the bearing has high bearing capacity and long-term stress, resulting in the bearing is prone to failure compared with other parts. Among all kinds of mechanical failure types, bearing failure accounts for a large proportion.
In contrast, the radial dimension of the rolling bearing is larger than that of the sliding bearing, and the damping capacity is relatively poor. When the mechanical equipment is at high speed, the service life of the rolling bearing is lower than that of the sliding bearing, and the noise is also relatively high.
The main function of the radial bearing is to bear the radial force, which consists of four parts, namely, the inner ring, the outer ring, the rolling element and the rolling element cage. The inner ring is tightly sleeved on the journal and rotates synchronously with the shaft, while the outer ring is in the bearing seat hole.
When the inner and outer rings make relative rotation, the rolling will roll on the raceway of the outer circumference of the inner ring and the inner circumference of the outer ring. In order to prevent friction, the cage separates the two. In most cases,
the reason why the bearing has problems is mainly due to the looseness of sealing shaft sleeve, fixing bolt and other parts during operation, resulting in the wear of rolling element and rolling element cage,
or there are gaps in bearing gland and shaft sleeve, impurities such as water or dust enter the bearing box from these gaps, and the lubricating oil becomes dirty, resulting in poor lubrication, which eventually leads to bearing failure.
2. Bearing damage.
Under normal circumstances, as long as it is used normally, the bearing can be used until the fatigue life. Bearing failure is called bearing failure when the bearing is not durable, premature damage and relatively early damage of fatigue life.
The reason is that the bearing failure is generally due to the failure to pay attention to the lubrication of the bearing during installation or use, resulting in the intrusion of foreign matters from the outside, or poor lubrication caused by the thermal influence of the bearing shell, resulting in premature damage.