It is the most obvious to judge the accumulation o

2022-08-08
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Clearly determine the accumulation of material in the scraper cavity of the vertical mill

a-toxr-50 vertical mill produced by FLS company is used for the first-line raw material mill of an enterprise, with a production capacity of 320t/h and a main motor power of 3500kW During the operation of the vertical mill, sometimes the slag spitting material is larger than the quantity of finished products sent away, which accumulates from the discharge port into the scraper cavity of the vertical mill, hindering the operation of the scraper of the vertical mill, resulting in the operation of the mill. 1. The stroke of the hydraulic universal material testing machine is an abnormal phenomenon that the maximum stroke resistance can be determined during the testing of the testing machine increases, the power of the main motor increases abnormally, and the vibration increases

judgment of blockage of vertical mill 1 Judge from the central control operation parameters. The power of the main motor rises abnormally. Generally, the grinding pressure, bed thickness and its corresponding main motor power fluctuate slightly within a certain range. The higher the bed thickness, the greater the power of the main motor. If the thickness of the material bed is thin (within the normal range), and the power of the main motor is hundreds of kW higher, it indicates that there is a possibility of material accumulation in the scraper cavity. Therefore, the power of main motor is the most sensitive parameter of plugging; The differential pressure of the mill increases and the inlet negative pressure decreases. The intersection of the hot air duct of the mill is the scraper cavity of the mill. The hot air flows upward from the scraper cavity through the inclined guide vane at the spray ring to produce a strong swirl into the grinding cavity for drying and lifting. The accumulation of material in the scraper cavity will inevitably lead to the reduction of the ventilation area, the obstruction of ventilation, the reduction of the negative pressure at the inlet of the mill, and the constant air drawing of the outlet mill fan, resulting in the rise of the differential pressure of the mill, and the vibration of the mill continues to fluctuate at a higher level. This kind of vibration is different from the small amplitude vibration during normal operation, and also from the sudden vibration (with a very high peak at an instant) caused by the iron parts entering the grinding cavity. It always vibrates at an amplitude 1 ~ 2mm/s higher than the normal vibration value; The temperature at the inlet of the mill decreases slowly, and the temperature detection thermocouple at the inlet of the mill is installed in the scraper chamber. If the failure of the thermocouple itself and the influence of the kiln tail gas temperature are excluded, it means that the thermocouple probe has been buried in the slag material and cannot be contacted with the air flow

if the above four parameters are abnormal at the same time, it can be clearly determined that there is material accumulation in the scraper cavity of the vertical mill

2. On site inspection and judgment. Look at the amount of slag. If the slag is larger than usual, check the slag discharge hopper of the mill and listen to the sound of unloading at the hopper. If there is no accumulated material in the discharge hopper, the slag material scraped off by the vertical mill scraper will fall into the bucket very crisp. You can also hit the bucket wall with a hammer. If the sound is stuffy, there will be material accumulation in the hopper. If the blockage is serious, ash will be sprayed outward from the sealing part of the running part and static part of the vertical mill on the upper part of the reducer

factors causing blocking of vertical mill 1 Limestone has poor grindability. In the feed of vertical mill, limestone accounts for the majority, while sandstone and iron powder account for only a small part. Even if the sandstone has poor grindability, it has no great impact on the grinding operation. If the grindability of limestone is poor, the slag spitting material will increase significantly during the operation of the vertical mill. If the operation is not adjusted in time, material blockage will occur

2. Improper operation. The operation simply pursues the hourly output. In the case of poor grindability of limestone and increased slag discharge, it still maintains a high hourly output for a long time. However, the current value of Roots blower of the pneumatic lift pump entering the warehouse does not increase, which indicates that the increased feed is not ground into raw material entering the warehouse, but only the slag spitting cycle. On the other hand, it is related to the fact that the feeding keeps a good growth momentum in operation, and the grinding pressure and air volume settings fail to keep up

3. The slag discharge port is blocked. There are two main factors causing the blockage of the discharge port: one is the iron block at the discharge port, causing the passing amount of slag spitting material to become smaller; the other is that the water spray volume of the mill on the operation is too large, and the water spray pipe of the mill is disconnected, causing the water to flow down without atomization, making the slag spitting material damp and blocking the discharge port

the treatment of mill blockage should immediately reduce the feeding amount by about 50 ~ 100t/h, and increase the system ventilation to appropriately increase the grinding pressure. Generally, it can return to normal state after 1 ~ 2H adjustment. If you don't see this kind of strange chemical material in SIFE laboratory because of the machine itself, you can only stop the material, empty the accumulated material in the scraper cavity, and then re feed

if the discharge port is stuck, you can cut the hole with gas cutting without stopping grinding the feed, fix the iron block with iron wire, and take out the stuck iron, but prevent the iron block from falling and scratching the downstream belt. If the material is blocked due to moisture, the grinding must be stopped for treatment. When the discharging capacity of the vibrating feeder is small, the angle of the eccentric hammer of the vibrating feeder can be adjusted in the shutdown state to achieve the designed conveying capacity

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