Cause analysis and treatment of vibration of the h

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Cause analysis and treatment of vibration of ring coal crusher

Abstract: This paper briefly introduces the vibration of ring coal crusher, analyzes the causes of vibration of coal crusher, and puts forward the measures to solve the vibration

key words: coal crusher; Vibration; Analysis and treatment

1. Overview

the coal used in the boiler of coal-fired power plant is usually raw coal that has not been classified. The particle size of raw coal mostly does not meet the requirements of coal used in the boiler and needs to be broken. Therefore, coal crushers should be set in the coal handling system of coal-fired power plant to break the coal into a certain particle size to meet the requirements of boiler combustion. The coal crusher installed by Pingwei Power Generation Company is a ring coal crusher made by PC company of the United States. In 1989, it was put into operation to improve the infiltration of filler by the matrix. Sixteen years of operation practice has made us have a further understanding of the ring coal crusher, and also accumulated some experience in dealing with faults. Here, we have an exchange with you on the vibration causes and treatment methods of the coal crusher

1.1 specification parameters of ring coal crusher

model tkk48 × 103 "

production capacity 1000 t/h

motor power 560 kW

speed 750 R p. M.

outer circle track of rotor ring hammer 1220 mm

feeding particle size 300 mm

discharging particle size 20 mm

bearing model 22234ck/c3/w33

number of ring hammers 2 × 18+2 × 16 = main structure and working principle of 68

1.2 ring coal crushers

are mainly composed of frame, rotor, grate plate, synchronous regulating device and upper cover hydraulic opening device. Its working principle is that when the motor works, the rotor rotates at the same time through the coupling, and the ring hammer is thrown out by centrifugal force from the original free falling state to make a circular motion along the maximum circular track. When the coal feeding elastic bandage tensile tester is an experimental machine for mechanical testing for users who produce bandage materials for a long time, when it enters the crushing chamber, it is first hit by the high-speed rotating ring hammer, and then hit by the impact plate Extrude and grind until the coal is crushed to a qualified particle size

2. Common vibration causes and treatment

2.1 rotor imbalance. Because the ring hammer of the coal crusher is broken, worn and sticky, the rotor is unbalanced, and centrifugal inertia force is generated in motion, causing vibration. Balance and replace the ring hammer to ensure that the weight difference between the symmetrical ring hammer and the suspension hammer shaft is less than 0.17kg

2.2 the bearing is installed incorrectly or damaged. If the bearing clearance is too large due to installation problems, the bearing clearance can be adjusted by locking the nut. If the bearing is damaged or worn so that the clearance is too large, it should be replaced with a new bearing. The bearing assembly clearance standard is 0.178mm

2.3 the coupling center deviation is large. The coupling shall be re centered so that the non parallelism and different axial degrees of the end face are ≤ 0.10mm, and the installation amount of elastic steel sheets is 36 ~ 40

2.4 the retaining gasket of the bearing locknut is damaged, causing the nut to loosen without problem and produce vibration. Replace the damaged retaining gasket and adjust the locknut to make the bearing clearance meet the standard

2.5 the coal feeding in the chamber of the coal crusher is uneven or the coal falling pipe at the feed inlet is seriously sticky, which leads to the fact that the coal feeding in the chamber cannot be evenly distributed along the length of the rotor, causing the rotor to vibrate due to uneven stress. Operate the coal feeder correctly to make the coal quantity uniform, clean up the sticky coal in the coal chute in time, and make the coal in the coal crusher chamber evenly distributed along the length of the rotor

2.6 the foundation bolts of coal crusher are loose or the foundation strength is insufficient. Check and tighten the anchor bolts and reinforce the coal crusher foundation

2.7 the foundation bolts of the drive motor are loose or the bearings are damaged. Align the drive motor again and replace the damaged bearing

2.8 the compression nuts of the end plates on both sides of the rotor are loose. Tighten the compression nut of the end plate and firmly spot weld with the top sleeve

2.9 the foundation of the coal crusher sinks or the cement is loose and damaged. Check, adjust or re grout the coal crusher foundation to ensure that the foundation is firm. It is suggested that the coal crusher of the new power plant should be equipped with vibration damping device to reduce the vibration of the coal crusher on the support foundation

2.10 internal parts of coal crusher are loose. Check whether the sieve plate frame, sieve plate, striking plate and lining plate are loose, and tighten all bolts

3 analysis and treatment of rare vibration causes

there are defects in the design of the bedplate support of the rotor bearing seat, as shown in Figure 1

there are only two steel plates between the base plate of the bearing seat and the bottom plate of the coal crusher. These two supports not only bear the gravity of the rotor, but also bear other loads generated by the rotor during operation. Therefore, the strength of the two supports is insufficient, and the long-term operation is subject to the effect of alternating stress, resulting in the fatigue of the support rib plate, which reduces the strength and produces linear displacement and vibration, which intensifies with the increase of the load of the coal crusher

treatment measures: improve the base plate support of the bearing pedestal on both sides of the coal crusher rotor (see Figure 2), improve the strength of the bearing pedestal foundation, and ensure the stable operation of the coal crusher rotor

the improvement plan is: the base plate support of the bearing pedestal on both sides of the coal crusher is increased from the original two rib plates to four, and the support strength of the bearing pedestal of the coal crusher is strengthened. Accurately measure the distance between the bearing pedestal and the bottom plate of the coal crusher, use A3 steel plate with a thickness of 20mm to make the supporting rib plate, and the blanking size error shall be controlled between 0 - -0.30mm. When welding the supporting rib plate, symmetrical spot welding and segmental welding shall be carried out first, and finally full welding shall be carried out. Attention shall be paid to prevent the deformation of the bearing pedestal caused by the welding process from intensifying the vibration. Through the improvement of the support of the coal crusher rotor bearing pedestal and the observation and measurement records for half a year, the vibration value is ≤ 0.12mm, and the coal crusher operates well

4 conclusion

the vibration of coal crusher is easy to cause damage to rotor bearing and foundation, and the causes of vibration of coal crusher are relatively complex. This paper analyzes the causes of the vibration of the coal crusher and puts forward the treatment measures. In practice, it should be analyzed and treated in time according to the specific situation of the vibration, so as to ensure that the coal crusher should remember not to make random decisions about the normal operation of the coal crusher. (end)

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