Vertical Roller Mill For Cement Grinding

Vertical Roller Mill For Cement Grinding

Cement Vertical Roller Mill maintenance method

The Cement Vertical Roller Mill better realizes the comprehensive utilization of slag. However, due to the wear and tear of the wear-resistant parts inside the Cement Vertical Roller Mill, it is difficult to control, and its serious wear and tear easily cause major downtime accidents, which will bring unnecessary economic losses to the enterprise. Therefore, maintaining the wearable parts in the mill is the focus of overhaul.

After years of research and application of the Cement Vertical Roller Mill, our company found that the wear inside the mill is directly related to the system’s output and product quality. The key wear parts in the mill are: sorter moving, static vane, grinding roller and grinding disc, and louver ring for air distribution. Preventive maintenance and repair of these three parts can not only improve the operation rate of the equipment and the quality of the products, but also avoid many major equipment failures.

First, the Cement Vertical Roller Mill process

The motor drives the grinding disc to rotate through the reducer. The hot blast stove provides a heat source, enters the inlet below the grinding disc from the air inlet, and then enters the Cement Vertical Roller Mill through the air ring (air distribution port) around the grinding disc. The material falls from the feed port to the center of the rotating grinding disc and is dried by hot air. Under the action of centrifugal force, the material moves toward the edge of the grinding disc and is crushed by being caught at the bottom of the grinding roller. The powdered material continues to move on the edge of the disc, and is carried by the high-speed upward airflow at the wind ring (6~12 m/s). The large particles are folded back to the grinding disc, and the qualified fine powder passes through the sorter to collect. Device. The whole process is summarized as: feeding & mdash; drying & mdash; grinding & mdash;

Second, the main wearable parts and maintenance methods in the Cement Vertical Roller Mill

1. Determination of the repair time

After four steps of feeding, drying, grinding and powder selection, the material in the mill is worn by the hot air. The longer the time, the larger the air volume and the more serious the wear, especially in production. The parts are the air ring (air distribution port), the grinding roller and the grinding disc, and the sorter. The main parts of these drying, grinding and collecting are also the parts with more serious wear. The more timely the wear situation is, the more convenient it is to repair, and it can save a lot of man-hours during maintenance, which can improve the operation rate of equipment and increase production.

Maintenance method:

Taking the Cement Vertical Roller Mill as an example, at first, in addition to the emergency failure in the middle, the monthly repair is also the main maintenance and repair cycle. Due to the operation, the output is not only affected by the air volume, temperature and wear, but also has other factors. In order to facilitate the timely elimination of hidden dangers, the monthly revision is revised to half-month fixed. In this way, no matter whether there are other faults in the middle, the main repairs are fixed. In the fixed repair, the hidden troubles and key wear parts are checked frequently and repaired in time to ensure zero-fault operation of the equipment during the 15-day repair period.

2. Inspection and maintenance of grinding rolls and grinding discs

The Cement Vertical Roller Mill generally consists of a main roller and a secondary roller, the main roller acts as a grinding, and the auxiliary roller acts as a cloth. During the working process of Shanghai Shibang Machine Cement Vertical Roller Mill, it is necessary to re-treat by wire welding due to the possibility of intensive wear in the local area of ​​the roll sleeve or the grinding disc. When the worn groove reaches 10 mm deep, it must be re-worked. welding. If there is a crack in the sleeve, the sleeve must be replaced in time.

Once the wear layer of the roller sleeve of the grinding roller is damaged or peeled off, it will directly affect the grinding efficiency of the product, reduce the yield and quality, and if the falling off material is not found in time, the other two main rollers will be directly damaged. Each roller sleeve needs to be replaced with a new one after it is damaged. The working time for replacing the new roller sleeve is determined according to the experience and proficiency of the staff and the preparation of the tool, which is as fast as 12 hours and as slow as 24 hours or longer. For the enterprise, the economic loss is very large, including the investment of new roller sleeves and the loss caused by the suspension.

Maintenance method:

In the half-month fixed repair cycle, the roll cover and the grinding disc were inspected in time, and the thickness of the wear-resistant layer was found to be reduced by 10 mm. The relevant repairing unit should be immediately arranged to carry out on-site welding repair. Generally, the repair of the grinding disc and the roller sleeve can carry out system inspection and maintenance on the entire production line of the Cement Vertical Roller Mill within three working days. Due to the strong planning, it can effectively ensure the concentrated development of relevant work.

In addition, during the inspection of the grinding roller and the grinding disc, other attachment parts of the grinding roller, such as connecting bolts and fan-shaped plates, should be carefully inspected to prevent the connection bolts from being worn and severely connected, and the equipment is detached during operation. , resulting in serious grinding roller, wear plate wear layer damage accident.

3, inspection and maintenance of the air outlet louver ring

The air distribution louver ring uniformly guides the gas flowing out of the annular duct into the grinding chamber, and the angular position of the louver ring blade has an influence on the circulation of the grinding raw material in the grinding chamber.

Maintenance method:

Check that the louver ring of the air distribution port is close to the grinding disc. The gap between the upper edge and the grinding disc should be about 15 mm. If the wear is serious, the round steel should be welded to reduce the gap. At the same time, check the thickness of the side plate. The inner plate is 12 mm and the outer plate is 20 mm. When the wear is 50%, it needs to be repaired with wear-resistant plate; focus on the louver ring under the grinding roller. If the overall louver ring of the air distribution ring is found to be seriously worn, the overall replacement will be carried out during overhaul.

Because the lower part of the louver ring of the air distribution port is the main space for replacing the blade, and the blade is a wear-resistant part, it is not only heavy, but also has a number of 20 pieces. It is replaced in the wind room at the lower part of the air ring, and the welding chute needs to be welded, and the lifting equipment is needed to assist the completion. . Therefore, in the fixed repair, the wear parts of the air distribution port are repaired in time, and the angle adjustment of the blades can effectively reduce the number of replacement blades. According to the overall wear resistance, it can be replaced once every six months.

4. Inspection and maintenance of dynamic and static blades of sorter

Shanghai Shibang Machine Cement Vertical Roller Mill Stud Connection Basket Sorter is an air flow sorter. The ground and dried material enters the sorter along with the airflow from the bottom. The collected material enters the upper collecting passage through the gap of the blade, and the unqualified material is blocked by the blade, or is returned to the lower grinding zone by the own gravity to be ground twice. The inside of the sorter is mainly a large squirrel-cage structure revolving bin. The outer baffle has stationary blades, which form a swirling flow with the blades on the rotating squirrel cage to collect the powder. If the dynamic and static blades are not welded firmly, under the action of wind and turning force, it is easy to fall into the grinding disc and jam the rolling equipment inside the grinding machine, causing a large shutdown accident. Therefore, the inspection of the moving and stationary blades is grinding. One of the focuses of internal maintenance.

Maintenance method:

In the inner squirrel cage revolving bin of the sorter, there are three layers of moving blades, 200 pieces per layer. In the fixed repair, it is necessary to vibrate the moving blades one by one with the hammer to see if there is any activity phenomenon. If so, it needs to be fastened, marked, and concentrated and welded. If it is found that there are severely worn and deformed blades, it needs to be dismantled, and according to the drawings, install new moving blades of the same size, and weigh them before installation to prevent loss of balance.

To check the stationary blades, remove five moving blades per layer from the inside of the squirrel cage to leave enough space to observe the connection and wear of the stationary blades. Turn the cage to check whether the joints of the stationary blades are open or worn. All wear parts need to be welded with J506/Ф3.2 electrode. Adjust the angle of the vane, the vertical spacing is 110 mm, and the horizontal angle is 17 & deg; to ensure the quality of the powder.

During each inspection, enter the classifier to observe whether the angle of the vane is deformed and whether the vane is loose. Generally, the distance between the two baffles is 13 mm. In the inspection, the rotor shaft connecting bolts should not be ignored, check whether it is loose, and the abrasive material adhering to the rotating parts should be removed. The overall balance should be made after the inspection.

to sum up:

The operating rate of the host equipment in the mineral powder production line directly affects the output and quality. The maintenance of the main engine is the focus of enterprise equipment maintenance. For the Cement Vertical Roller Mill, it has targeted and planned maintenance, and does not overlook the hidden dangers of the internal wear-resistant parts of the Cement Vertical Roller Mill. It can predict the pre-control in advance and eliminate the hidden dangers in advance, which can prevent major accidents and improve. The operating rate of the equipment and the production time of the machine provide guarantee for efficient and low-cost operation of the production line.

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