Bearing seizure in the GKH horizontal scraper discharge centrifuge
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The GKH horizontal scraper discharge centrifuge relies on a belt to drive the shaft and drum; the day before yesterday, smoke was observed coming from the bearing near the pulley end, after which the entire machine stopped working. Now that the pulley has been removed and the bearing cover taken off, it was found that the bearing (type 6240) had suffered severe sintering; the inner ring of the bearing was heavily scratched, and there was also a significant misalignment between the inner and outer rings. It seems that there is a considerable axial force acting in the direction of the pulley. What could be causing this? This type of centrifuge shouldn’t have such high axial forces. Also, the centrifugal drum can’t be removed right now. Do any experts have any good methods? A 20-ton jack didn’t move it at all, and we tried heating it with low-pressure steam for half a day with no success either. Please suggest some effective solutions!
20T won’t work; go with 100T. The bearings burn out probably due to insufficient oil or excessive radial stress on the bearings, which causes the bearing temperature to rise and thus the oil temperature to become too high, preventing the formation of an oil film
May I ask where this axial force comes from? The inner ring of the bearing is displaced to a very serious extent……
1: The feed to the centrifuge is uneven, resulting in significant vibration. 2: The temperature sensor is damaged. 3: There is a very good bearing layout here, so there should be no problems. 4: It is originally a positioning bearing, so its load-bearing capacity is not high. 5: Use special tools to eject the drum.
A puller was made; previously a 20-ton one was used but it wasn’t able to move the object, so a 100-ton one was purchased. After being used, it was found to be defective, and it seems that the new one has not arrived yet.
The centrifugal drum also cannot be removed because the heating method is incorrect; the scraper used for unloading generates axial force, so adjusting the angle of the scraper helps to reduce this backward axial force. Check whether the lubrication oil hole is blocked.
Where does the axial force come from? Excessive axial force is generated during unloading with a scraper.
With the correct heating method, two screws are sufficient to pull out the rotor, and no special tools are required. If a jack is to be used, it is recommended to opt for a mechanical one, as hydraulic jacks have cushioning. Be careful of vibrations and rotation when pulling.
Are you saying that the edge of the scraper is not parallel to the axis of the drum when it scrapes? Does that result in a component along the axis? It’s possible; take another closer look
It uses a mechanical system, and it is heated with low-pressure steam for half a day; the temperature of the steam is around 150 degrees
This post was last edited by li*nji on 2012-4-11 23:01. Be careful! Prolonged heating may cause deformation; check the centrifuge manual! There is a drum removal method, yes! To disassemble the drum assembly, first remove components such as the shaft end seal cover (3-2) and the basket pressure cover (3-3). Since the entire drum assembly is quite heavy (about 5.1 T), special lifting tools (provided by our factory) as well as tapered disassembly tools are required for its removal. The tapered disassembly tool (model: ZYC-A, a hydraulic disassembly tool with a tapered fit, manufactured by Dezhou Hydraulic Machinery Factory) must be purchased by the user. The specific disassembly procedure is as follows: Connect the oil pipe of the tapered disassembly tool to the screw hole at the spindle end, then inject high-pressure oil at approximately 250 MPa into the annular groove on the spindle’s tapered surface. When oil begins to flow out from this surface, it indicates that the mating surface between the drum and the spindle has become loose. Next, connect the lifting tool to the drum (35-0), and use this combination to lift the drum out of the machine. After the drum has been removed, the air seal pressure cover assembly (432-0), the air seal device (431-0), and the front bearing pressure cover (430-0) can be removed one after another. The pulley (3-13) can be taken out using a special removal tool designed for the driven wheel’s hook. Then, components such as the rear bearing pressure cover (4-14), the rear bearing sleeve (3-12), the nut and rear bearing sleeve (3-11), and the round nut (3-10) can be removed. The spindle can be taken out from the front of the bearing housing using a double-ended screw, a screw rod, and a pressing plate. At this point, the rear bearing (B0308) also moves out of the bearing cone sleeve (3-8). Finally, the spindle is slowly moved out of the machine. Once it is placed flat, the remaining components on the spindle can be removed. Note: To prevent accidents, in addition to using the drum lifting tool (00FJ8-0) when removing the spindle, two mechanical jacks (00FJ9-0) are also necessary. The specific usage method is described later. Note: When the drum cannot be removed by disassembly, lifting tools can be used to remove both the drum and the shaft at the same time (see Figure 17), lift them to a suitable location, and then use other methods to take the drum off.