Inspection and maintenance of high pressure roller mill

Date: 2019-07-10 Views:

Due to the large volume of the high-pressure roller mill, it takes a long time in the process of maintenance. The high-pressure roller mill affects the normal production of the plant during the maintenance process. Therefore, the high-pressure roller mill is required in the actual production process. Machine maintenance and timely maintenance. The places where the high-pressure roller mill is more prone to problems when it is applied in our company are the roller surface and the bearing ball.

1. Analysis of the roll surface problem of high pressure roller mill


The effect of the roll surface of the high-pressure roll mill after a long period of wear is shown in Figures 1 and 2.


Figure 2 High pressure roller mill roll surface


The maintenance of the high-pressure roller mill is mainly focused on the wear resistance of the roll surface and the repair of the wear. The pin roller surface of the high-pressure roller mill has high hardness and good wear resistance, and can form a lining to protect the roller sleeve mother body. However, in the later stage of use, due to the edge effect of the high-pressure roller mill and the separation of the steady flow weighing material, the wear of the roll surface is uneven, and the wear characteristics of the two ends are small and the middle wear is large, which affects the roll grinding of the high-pressure roll mill. Product yield and quality. For different materials, the corresponding wear-resistant roll surface should be selected. The hardness of the roll surface should be higher than the hardness of the ore, otherwise the wear will be very fast. Due to the wear of the roll surface of the high-pressure roller mill, the performance parameters such as output, extrusion effect, energy consumption, etc. will change, and adjustment at any time is very necessary, in order to obtain long-term stable benefits. At present, the maintenance of the roller surface of the high-pressure roller mill is mainly based on the manual replacement of the roller nails. Firstly, the bad roller nails are removed in time, and the new roller nails are replaced in time by the original roller nail positions. The degree of wear on the roll surface of the high-pressure roll mill is mainly related to the hardness of the ore. The greater the hardness of the ore, the more severe the wear on the roll. In addition, a corresponding silo is usually arranged above the high-pressure roll mill to form a column between the two rolls, which can effectively avoid the secondary friction generated by the material falling on the roll surface of the high-pressure roll mill.

2. Analysis of bearing ball problems in high pressure roller mill


The bearing balls of the high-pressure roller mill are damaged as shown in Figures 3 and 4.

Figure 3 High-pressure roller mill bearing ball fragmentation

Figure 4 High-pressure roller mill bearing ball crushing and wear

For high pressure roller mills, the balls in the bearing have an important position. Usually, if the ball may be injured inside the ball due to uneven force or other reasons, the final result is the same as that in Figure 3. Not only that, but the single ball has problems, and the ball near the injured ball is gradually injured and worn. As shown in Fig. 4, the ball on the right side of Fig. 4 has been completely damaged, and the ball on the left side is also affected by wear and deformation due to the influence of the ball on the right side. The surface of the ball in the bearing is smooth. If the broken ball slag falls on the other intact roller surface and the bearing gap, it will cause other ball surface damage. The effect of debris falling from the ball on the inside of the high-pressure roller mill bearing is shown in Figure 5.

Figure 5 The surface of the high pressure roller mill bearing is slightly damaged


If there are slag or other harder materials in the bearing of the high-pressure roller mill, abnormal noise will occur due to friction. Therefore, in the process of running the high-pressure roller mill, the abnormal noise of the bearing or other conditions needs to be stopped and repaired in time to avoid causing damage. Bigger losses.

3. Analysis of other common faults and causes of high pressure roller mill


(1) The moving roller moves irregularly in the horizontal direction. A possible fault is that the nitrogen accumulator is not sufficiently pressurized or damaged.

(2) The hydraulic oil temperature is high. Possible faults are severe internal leakage or excessive pump start-up time, and the hydraulic system needs to be checked.

(3) The nip is too large. The reasons may be: A roller surface wear is serious; B is no pressure; C displacement sensor position setting is unreasonable; D roller has accumulated material, need to be treated as appropriate.

(4) The nip is too small. The cause may be a problem with the gap block size or the displacement sensor position setting is incorrect.

(5) The roller is stuck. This may be caused by foreign matter between the rollers or too much between the rollers during startup.

(6) The roller does not turn. The cause may be: A motor failure; B fluid coupling problem; C reducer failure; D hydraulic expansion disk loose; E signal transmission failure.

(7) The bearing temperature is too high. The cause may be: A water cooling system has a problem; B grease supply is insufficient; C grease number is wrong.

(8) Lubrication system If the bearing labyrinth seal is found to have no grease overflow, there may be the following reasons: A lack of oil; B pipeline failure; C heating device is broken; D grease pump is broken. If it is found that the color and properties of the oil flowing out from the non-load end bearing oil drain port have changed, it may be that lubricating oil or other foreign matter is mixed in the lubricating grease.

4. Precautions for operation and maintenance of high pressure roller mill


(1) It must be ensured that the straight hopper above the high-pressure roller mill has a sufficiently high column so that both rollers are always buried under the material.

Figure 6 High pressure roller abrasive column


(2) Stop immediately when a sudden safety accident occurs. At the same time, the upstream belt should be turned off. Otherwise, within a few seconds, the material will pile up the straight hopper and block the belt lowering port, which will cause the belt to frictionally burn for a short time. Similarly, if the discharge belt stops during operation, it will have serious consequences. Therefore, the high pressure roller mill should be interlocked with the upstream and downstream belts.

(3) Since the function of the high-pressure roller mill is very important and the structure is complex, a special operation and maintenance account should be established to record the operation and maintenance status of the equipment on a daily basis, including: cumulative running time; temperature and pressure of each test point. , flow, current and other data; description of abnormal phenomena; time, content, effect and maintenance of fault handling; grease replacement time and time interval.

(4) The quality of lubricating grease must be strictly controlled to fully meet the requirements of the equipment. For example, grease distributors are mostly imported fittings, which are very precise. Their lifespan is long under normal use conditions. However, many domestic manufacturers often replace the dispensers because the impurities are mixed in the grease and block the valve parts in the dispenser. Stuck. At the same time, because the accessory is more precise, it is not easy to repair, and it has to be replaced, which causes a great waste.

Figure 7 High pressure roller mill lubrication system


(5) The temperature change of the bearing and the flow rate of the circulating cooling water pipe should be checked frequently to ensure that the circulating cooling water is evenly distributed to each cooling position.

(6) The surface of the roller should be inspected regularly every month. Refer to the surface measurement data during roller installation and commissioning to compare and determine the condition of the roller, wear rate, replacement time or repair measures.

(7) Iron blocks and sundries are strictly prohibited from entering the equipment. The inclusion of impurities in the iron material not only affects the hydraulic system, but also seriously damages the surface of the roller and directly affects the rolling effect.

(8) The gap size of the sealing plate on the end side of the roller should be checked regularly to prevent the material from diarrhea from the end and affect the rolling effect. The materials on the slide of the moving roller chock and the waste oil in the grease collection box should be cleaned regularly to ensure flexible operation of the equipment. In the winter, ensure the normal operation of the grease heater and the resistance insulation wire to prevent grease blockage.

(9) During the operation of the high-pressure roller mill, the personnel in the central control room need to monitor various indicators in real time, and find problems in time for remote processing or notify the on-site workers to avoid secondary damage.

Figure 8 High-pressure roller mill operation monitoring system


(10) The high-pressure roller mill should be thoroughly inspected before and after the equipment is used. It is found that the connection point is loose and the screw should be tightened in time. It is found that the amount of lubricating oil is insufficient to be added in time, so as to reduce the between parts in production. Friction to extend the life of the device. After the high-pressure roller mill is finished, stop the feeding, and then turn off the power after all the materials are discharged.

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