The single-roller crusher of the sinter plant is responsible for the crushing task of high-temperature sinter. The area where the toothed roller portion and the slab body are combined is not only the crushing chamber V but also the process flow channel of the sinter. The normal operation of the toothed roller is both a prerequisite for achieving the crushing function and a necessary condition for the smooth flow of the sinter process. Over the years, blockage accidents caused by stalling of the toothed rolls caused by various reasons have occurred. In the accident handling, the operators often use pressurized water to reduce the strength and temperature of the sintered ore to shorten the accident handling time. Accelerate the pulverization of sinter and affect product quality. Simultaneously. The large amount of water vapor generated by the flushing also affects the normal operation of the tail electric dedusting and corrodes the polar plates. Especially when the accident is found late and there is more accumulation of hot lump ore, a large amount of flushing also causes the volume of the sinter to expand. There have been accidents in the crusher casing observation door, hot mines and high-temperature steam ejected, which constitutes a serious threat to safety. Therefore, tracking accidents, identifying the cause of accidents and taking corresponding measures are of great significance for the maintenance of crushers and the normal production and safe production of sinter.
2 Accident scene investigation and cause analysis 2.1 Equipment crushing principle, transmission program and accident The crusher model is 1100X1600 single-roller star wheel crusher. See the transmission method. The crushing principle is the slab body installed in the lower part of the star wheel. The star-shaped wheel of the rotating toothed roll crosses at a frequency of 4 to 5 times per minute to form a shear type. The transmission sequence is that the motor 1 transmits power to the speed reducer 3 through the toothed hand 2, and the speed reducer 3 is output through the open pinion 5 on the low speed shaft 4, and is transmitted to the open large gear 6, and the open large gear 6 passes through the safety pin 7. The body 11 is transferred to the body 11, and the body 11 is transferred to the toothed roller portion 8 by a flat key.
The accident profile is when the motor to the low speed shaft of the reducer rotate normally and the safety pin is intact. The accident that the tooth roll stopped and caused the blockage of the hot ore in the crushing chamber occurred. After the equipment was not simply taken, the test was carried out and the test was carried out for a period of time. This cycle has been repeated many times. The task of accident analysis is to find the accident point of the missing power through on-site investigation and take effective measures to cure this repeated accident.
2.2 The accident site investigation is based on the repairman's introduction. There are two unresolved hidden dangers in the crushing chamber. First, the gear unit 3 and the open gear box 10 are relatively narrow. It is more difficult to fasten the reducer by loosening the anchor bolt on this side. Secondly, the taper locating pin of the toothed roller bearing part has not been installed due to the supply and construction of the large diameter reamer. The two bearing seats are only positioned and fastened by 8 M36 bolts, so the plane positioning accuracy is poor. Another important clue is that the inner hole of each large gear 6 of the outer portion of the fuse portion 11 is designed to be a dynamic fit. Because of the difficulty in lateral assembly, the fitter grinds the inner hole of the large gear with a portable grinding wheel in the field assembly. This assembly may produce a gap of 1.52mnU with a wobble).
According to the operator, the crushing chamber has been blocked and the toothed roller has stopped. Therefore, it is an emergency stop. There was a creaking sound in the open gear box on the eve of the stop of the toothed roller.
2.3 Accident analysis According to the site investigation, it can be determined that the motor to the low speed shaft of the reducer is intact. The problem lies in the low speed shaft 4 (see) to the tooth roller portion 8. As can be seen, there are four weak systems. Bad sections may become the break point of the power transmission. First, the transmission key between the low speed shaft 4 and the pinion 5 is damaged and slipped. Second, the transmission key between the toothed roller portion 8 and the body 11 is damaged and slipped. Third, the insurance pin between the body 11 and the large gear 6 is idling after being cut. Fourth, the large and small gear meshing parts elastically retreat and slip. The third piece of insurance sales can be excluded from the introduction of maintenance workers. The first two or two can be eliminated after being cleared from the accumulated material for a few days. Now focus on the possibility of slipping between large and small gears.
The two hidden dangers mentioned in Section 2 lead to the open gear top clearance up to 8mm, exceeding the standard 5.5mm. The full height of the gear teeth with the modulus m of 10mm is 22.5mm, and the standard should be meshed by 20mm. Actually only spray 12ram. In other words, the gear tooth overlap is only 12mm, which is only 66% of the normal value of 20mm. In the transmission, the reducer anchor bolt may loosen 0.5mm, the bearing seat anchor bolt loose may be displaced 0. 5mm, bearing seat bushing backlash May be displaced after wear. 5mm, the clearance between the fuse body and the gear hole of the large gear may be 1. 52mm, so that the gear overlap is reduced to 8.59mm, which accounts for 45% of the standard whistle. It is assumed that the transmission is elastic. The accumulation of deformation causes the teeth entering the meshing zone under heavy load to retreat by 9 mm. Then, the gear slip with zero overlap is present.
A follow-up observation confirmed the above assumptions. The investigator intentionally did not arrange the installation of the open gear box cover between the two accidents in order to observe the entire process of the next accident. In the second accident, because there was no open gear box cover, the investigators witnessed the whole process of the large gear from irregular rotation to crawling and finally slipping and stopping, and at the same time emitting a strange noise. Moreover, accidents often occur when the strength of the sinter is high and the whole piece slips to the crushing chamber.
3 Countermeasures Discussion and Practice Section 3 analysis of the cause of the accident, to reduce the open gear top clearance, the conventional treatment method is to reduce the existing center distance of 708mm to adapt to the standard center distance of 700mm, but the reducer and the two bearing housing The anchor bolts are all on the concrete beam and there is no room for adjustment. Therefore, the first solution decides to first weld the retaining bolts from the middle of the AB in the direction of the arrow. Use a jack to hold it at C. This treatment has a certain effect, but because the site is a high-temperature dust zone, 24 hours in mechanical vibration, the anti-retracting bolts and jacks will loosen in the vibration, and the accident hidden danger has not been completely eliminated.
The second option is to design the motor and reducer on a swingable or movable mechanism. However, due to the heavy weight of the equipment, the space limitation of the upper part of the reducer is difficult to implement.
In this case, the author proposed a scheme for increasing the tooth gap.
According to the field investigation and analysis, the essence of the gear slip accident is that the field center distance of 708mm formed over the years is 5.5mm larger than the center distance of the design 700mm (standard tooth gap is 2.5mm). The gears are not properly engaged (see). In response to this situation, the first two schemes are trying to change the field center distance of 708 to adapt to the standard center distance of 700, and the scheme of increasing the tooth gap is to increase the number of pinion teeth and change the standard center distance of 700 mm to adapt to 708. Site center distance. That is, the center distance of 708 is normal, and its way of thinking is reverse.
4 transformation effect and maintenance recommendations 4.1 change effect can be seen from Table 1, in the output speed, the first speed after the transformation is 4.47n / mm, bounded between the two speeds before the transformation. The second speed of 6. 05n/mm has no effect on the sinter crushing than the 24n/miru before the transformation. 5mm,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, It can fully meet the normal production of sintering equipment.
Table 1 Comparison of parameters and normal values ​​before and after transformation (unit: mm) Parameter tooth number Output speed (n/min) Tooth top scalloped clearance Gap tooth overlap value Center distance Normal value after transformation before transformation After the implementation of the program, the pinion The tooth tip circle has been increased by 10 mm, the gear overlap has been increased by 5 mm, and satisfactory results have been obtained, which solves the production problem that has not been solved well for a long time.
4.2 Maintenance Proposal To make the production equipment operate normally and output well, it is necessary to do a good job in maintenance, repair and maintenance of the equipment. It is especially important to improve the quality of inspection and installation. It is recommended to adhere to the following principles in maintenance and assembly: assembly of the body and hexagonal shaft (transition and double-key connection). If the body heating assembly method is adopted, the assembly of the big gear and the body of the next process should be arranged on the next day. After the main body is completely cooled, it is necessary to carry out on-site measurement before assembly to prevent the assembly habit of the grinding wheel.
When the conditions are ripe, stick to the kit for overhaul.
In the equipment maintenance, take the anti-loose check of the reducer and the bearing seat fastener. The fastening of the reducer anchor bolts can be designed with special tools to assist in the fastening work.
5 Application of the increase of the tooth gap 5.1 The application formula is calculated from the standard gear transmission center distance formula: the relationship between the increase and decrease of the tooth tip clearance and the increase and decrease of the gear tooth number: (: 2000 edited Tong Xinmin nozzle Linyi Spot welding As shown in the figure, after the tooling and nozzle are installed, adjust the nozzle extension length, pilot a nozzle, install the top inspection size A, confirm the angle and the extension length, and then spot weld the nozzle.
In the actual processing, by using the tooling, the detection method and the like, a better processing effect is obtained = not only Z, but also. The number of teeth of a large gear; Z: the number of teeth of the small gear; the modulus of the gear of a m (mm): the tip clearance to be adjusted (mm>; Zi - the increase in the number of teeth.
In the application, R needs to substitute the tip clearance and gear modulus that need to be adjusted into the formula to get the number of teeth to be increased, and then choose to increase the number of teeth of the large gear or the number of teeth of the pinion.
5.2 Matters needing attention The gear adjustment scheme is limited to the case where the actual center distance is not the same as the gear center distance and the actual center distance is difficult to change. The increased tooth clearance scheme R is suitable for systems where the transmission ratio is not critical.
When choosing to add teeth to the pinion. It can save the cost of renovation.
When the output speed is required to be slightly higher than the original speed, choose to increase the number of pinion teeth or reduce the number of large gear teeth. The original manual operation efficiency has doubled, the cycle has been greatly shortened, and the design accuracy requirements have been met. The control of such spatial angular position is a good practice, and it also provides a reference for solving similar problems in the future.
When the clearance value CA is less than m/2, the gear displacement should be considered. In order to achieve the brewing accuracy.
6 Conclusion To reduce the tip clearance. Adjusting the center distance is the normal way, which is the normal design thinking when the center distance is undetermined. But at the production site. In the case where the center distance is framed by the factory, or in the case of multi-year production conditions (including the accident state), the center distance becomes large and it is difficult to recover from summer, how to solve the problem that the tooth tip clearance exceeds the standard, here is proposed to increase the tooth gap This is a solution that breaks through the traditional mindset. Although this program has objections in the early stages of its formation, it has proven to solve practical problems at the production site. This idea has certain value in solving the tip clearance adjustment under the same working conditions (that is, it is difficult to change the center distance and the transmission ratio is not very strict).
1ç³¸åŒ—å·¥å¦ It. Mechanical parts design thank you. 1975. Editor Wang Lijuan Germany EdelstahlLeuna built forging press The integrated forging center provided by Czech ZDAS company was put into production at EdelstaWLeuna, which includes a CKW 1800 ton open mold press. Forging robots and rough cars on QKK's 12-tonne track. The line is designed to forge bars, shafts, rings, bushings, flanges and other types of forgings. The press E is equipped with a moving anvil, a lower tool magazine and a tool changing system to realize its versatile process. In the upper and lower anvils, there is a structural steel insert which is welded to the mother body and greatly prolongs the forging anvil.晔倜Q Silicon Slow Tube Nursery Operation Unit. All of its actions are linked. The entire unit is controlled by an operator from the common control panel
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