Vertical grinding and grinding roller repair

Date: 2019-07-02 Views:

The characteristics of vertical mill:

1) High grinding efficiency;

2) the maintenance is convenient, and the maintenance can not be stopped;

3) Each roller is an independent system, there is no connection between the grinding rollers, and the maximum dynamic load is only related to the quality of a grinding roller;

4) the modular design is adopted, and the interchangeability of the components is high. Different specifications, different kinds of grinders (raw material mill and cement mill) can choose the same specification of component modules to achieve interchangeability. It can effectively reduce the stock of spare parts and improve the maintenance efficiency of abrasive equipment.

5) the linear velocity of plane grinding disk, conical roller and inner and outer sides of grinding roll tends to be the same, which can effectively reduce the uneven wear of grinding roll, high utilization ratio of wear-resistant material and long life of roller sleeve.

6) Elastic hydraulic system, strong anti-fluctuation ability, to ensure the stable operation of the mill;

7) the grinding roller is forced to lubricate with dilute oil, and the life of the spindle bearing can be increased by 2.5 times.

8)The grinding roller is arranged at 15° inclined, and the maximum oil level is below the static and static interface, which completely solves the oil leakage problem easily caused by the failure of oil seal lubrication with thin oil.
Due to the environmental impact of production, the abrasion of vertical grinding rollers cannot be avoided, such as Lescher Mill, Smith Vertical Mill, Special Vertical Mill, Shen Heavy Vertical Mill, etc. However, the traditional method is not only difficult to solve quickly, but also the cost is high. How to solve this problem perfectly is the concern of many enterprises.

1. First of all, the main reasons for wear of grinding roller are analyzed.

a: Manufacturing installation and routine maintenance aspects

1) it is not installed in strict accordance with the operating rules;

2) the inspection is not in place and the maintenance is not timely;

3) the surface treatment is not in place and the fastening moment is not uniform or not in place when the roller is replaced;

4)There are problems with the quality of the roll sheet(e.g. matching with the roller body, dimensional accuracy of the processed surface, etc.);

5) not strictly in accordance with the start-up fastening requirements and so on.

B: environmental aspects of equipment use

1) the operating temperature of the equipment is high and unstable;

2) the equipment material is unknown and the linear expansion coefficient can not be obtained or calculated.

C: objective analysis

1) factors of loosening roller bolt: after long operation, individual roller bolt loosens, resulting in unreal coordination between roller sleeve and hub. Resulting in friction between the roller sleeve and the hub, after a long time of friction, coupled with the large radial force of the grinding roll, it will inevitably lead to faster local wear, resulting in a gap between the roller sleeve and the hub, which can not ensure the contact area, which will lead to wear.

2) The factors of the welding of the roller cover: the roller sleeve shall produce a slight deformation at a time, the more the surfacing frequency, the thicker the overlaying thickness and the greater the deformation, so the radian of the round can not be ensured. In addition, if not in accordance with the correct build-up process, there is no guarantee of the prior overall pre-heating, or the preheating speed, the degree and the temperature, etc., and the deformation amount caused by the build-up welding is increased.

2、 Main points of repair of vertical grinding roller:

1) carrying out sand blasting treatment on the matched part to ensure the surface treatment effect;

2) welding the positioning points, and grinding the positioning points according to the template rule to ensure the concentricity and the taper after the repair;

3) The bolt must be tightened according to the specified torque: first, the bolt of the grinding roller shall be tightened three times according to the requirements. In addition, during normal shutdown, the degree of tightness of the grinding roller bolt shall be checked, and if there is any looseness, the bolt shall be tightened again, and the loose bolt shall be recorded and inspected to prevent the further deterioration;

3. On-site repair steps for wear of Leichee mill roller in Solay industry:

1) baking the injured part with oxygen-acetylene flame (master the temperature, avoid surface annealing), bake the oil that seeps into the metal surface until there is no spark splashing, in order to prevent the temperature is higher, can be divided into several baking;

2)Make the sample ruler(for restoring the size of the locating point)based on the non-worn surface;

3) the welding positioning points are uniformly distributed along the conical surface of the hub and the cylindrical fit surface;

4) using the template ruler as the basis, grinding the positioning point;

5) the wear surface is large or deep, if the time permits, a large area surfacing can be adopted, and the welding height is slightly lower than the positioning point;

6) cooperate with surface sandblasting treatment, meet the sandblasting standard of Sa2.5, use compressed air to blow clean;

7) empty test roll sleeve to check the fit gap;

8) clean the surface with acetone or anhydrous ethanol to ensure that the surface is clean, dry and rough;

9)Fully mix the Sore carbon nanopolymer materials in strict proportion, and mix them to a uniform color without color difference;

10)Remove the floating rust at the matching part of the roller sleeve, clean it with anhydrous ethanol, brush the stripping agent SD7000 and dry it;

11)Blend the nanopolymer material of Sore Carbon, scrape it to the mating surface and make it slightly higher than the original size of the mating surface, and assemble the roller sleeve vertically. Tighten the bolts according to the specified torque;

12) in order to ensure the normal operation of the equipment, it is necessary to ensure that: strict and careful installation; first of all, according to the requirements of a certain torque to fasten the roller bolt three times. In addition, when the roller bolt is shut down, the loosening degree of the roller bolt should be checked by spot check. If there is loosening, it should be fastened again, and the loose bolt should be recorded and followed up to prevent its further deterioration.

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