The maintenance of the high temperature centrifugal fan used for the clinker calcination of the rotary kiln is quite different from that of the conventional fan.

1) When adjusting the coupling between the motor, fluid coupling, and fan, it is not appropriate to use the following two methods for alignment:

① Measure radial and axial runout with feeler gauge with the help of auxiliary flat block;

②The two halves of the coupling do not touch. Use a dial indicator to fix it on the stationary half of the coupling. Let the probe measure the radial and axial runout of the other rotating half of the coupling.

Reason analysis: The high-temperature centrifugal fan coupling requires high alignment accuracy, and the coaxiality of its normal operating state must be guaranteed within 0.05mm. Use the above two methods to rectify. Due to the machining error of the coupling itself and the influence of surface dirt, the actual coaxiality value will often exceed the normal range several times or even ten times, causing serious vibration of the fan. Method ① is generally used for rough finding of couplings or occasions where the requirements are not high. It is not suitable for high temperature fan alignment; Method ② does not eliminate the influence of shape errors and still cannot meet the operating requirements of high temperature fans.

Correct way: Use 2 to 3 bolts to temporarily connect the two halves of the coupling, let them rotate synchronously, use 3 (quick alignment) or 2 dial indicators to measure the radial and axial runout values, and finally adjust to Specify the scope of requirements.

2) Although the above method is used to align the coupling, the coaxiality is also controlled within 0.05mm, but the influence of the expansion difference between the fan, the hydraulic coupling and the center line of the motor in the cold and hot states is not paid attention to. Or although I have paid attention, I mistakenly believe that the temperature of the fan is high in the operating state, so its cold center line should be lower.

Reason analysis: The temperature of the fluid coupling (up to 80℃) is higher than that of the motor and the fan bearing seat (oil pump lubrication) in the normal operation of the high temperature fan, and its thermal expansion is correspondingly higher. Therefore, the center line must be adjusted in the cold state. Lower. The high temperature environment where the fan impeller is located cannot be used as the basis for calculation of the central high thermal expansion.

Correct approach: In order to ensure that the center lines of the fan, fluid coupling, and motor are in a theoretically straight line during normal operation in the hot state, the center line of the fluid coupling is deliberately lower than the center line of the motor and fan by an expansion difference when the cold state is aligned. Δ, generally, Δ is 0.1～0.2mm

3) When reinstalling the fan bearing end cover (upper and lower 8 pieces in total), install the fixed end and free end cover incorrectly.

Reason analysis: In order to adapt to the thermal expansion caused by the high temperature environment of the fan shaft, the manufacturer designed a non-locating bearing at the tail. The positioning bearing is required to be strictly positioned during installation, and the expansion side of the free bearing cannot be restricted. If they are installed interchangeably, the free expansion and contraction of the shaft will be restricted, which may cause equipment accidents.

Correct method: According to the length of the flange of the bearing end cover inserted into the part, install the upper and lower half end covers with short flanges on the far side. At the same time, confirm that the positioning of other end caps is reliable, and the positioning is not poor due to the thickness of the sealing ring.

4) When aligning the equipment, use the method of tightening or loosening the anchor bolts to "collect" the relevant accuracy requirements. Or although the shim is used for adjustment, the shim is added between the motor or the fluid coupling and the bottom plate.

Reason analysis: Tightening and loosening the anchor bolts will cause uneven pre-tightening force of each anchor bolt, and it is easy to cause individual anchor bolts to be excessively stressed and damaged during operation, and in the future operation and maintenance process, it will be extremely It is easy to destroy the adjusted installation size. The motor and bottom plate, fluid coupling and bottom plate should be regarded as a whole, and the gasket can only be added between the bottom plate and the foundation shim.

Correct method: Use pad iron to adjust the installation size, add the pad iron between the bottom plate and the foundation pad iron, and when tightening the anchor bolts, ensure that the bolts are basically evenly stressed.

5) The fan bearings are lubricated by an oil pump. Normally, the bearings will not lose oil. Therefore, when the slinger ring is damaged, it is too lazy to reinstall it due to inconvenient installation.

The function of the oil slinger is that in the event of an unexpected power failure or a short-term failure of the oil station and the oil cannot be supplied normally, the oil ring can lift the oil from the oil pool in the bearing box to supply a certain amount of oil to the bearing to ensure its continued rotation Without being damaged. So it must be missing.