The problem of oil leakage in vertical grinding rolls often occurs in cement plants with vertical mills, which is a problem that has always plagued vertical mill manufacturers. Oil spills not only pollute the environment, but also increase production costs. There are many reasons for the leakage of the vertical grinding roller. There are two main points in the summary:
First, the reason for the grinding roller seal. At present, the vertical grinding roller seal mainly adopts three skeleton lip seals, one dustproof and two oilproof. However, the working environment of the vertical grinding is very harsh, and it belongs to the working condition of high dust, high temperature and shock vibration, so the seal wears quickly. And the sealing and replacement is very difficult. It is necessary to turn the roller and remove the grinding roller from the rocker arm. The work is time-consuming, laborious, and the maintenance cost is high.
Second, the grinding roller lubrication system does not return oil. When the roller is working, the bearing will generate some heat and it is in a high temperature environment. Therefore, it is generally lubricated by thin oil circulation, so that excess heat can be taken away to ensure that the bearing is in the normal temperature range. However, if the oil return is not smooth in actual work, the oil level in the grinding roller will rise and then overflow from the oil seal and the air cap.
The following reasons are caused by poor lubrication of the grinding roller lubrication system:
(1) Temperature reasons. When the grinding is started or the ambient temperature is too low, the temperature inside the grinding roller and the temperature of the oil return pipe are not high. Since the Vertical Roller Mill generally uses a lubricating oil with a viscosity of about 320 mm 2 /s, the fluidity is poor, so that the oil return is not smooth.
(2) Reasons for resistance. Lubrication of vertical mills generally adopts centralized lubrication. The other oil stations including the grinding roller lubrication station are concentrated in one room. The lubrication point of the vertical mill is generally far away, so the pipeline resistance is large, resulting in oil return. Not smooth.
(3) Reasons for pipeline intake. Because it is impossible to achieve the same amount of oil supply and oil return, in order to ensure that the oil level is not too high, the oil return is greater than the oil supply. The return oil is located at a low oil level that needs to be guaranteed. When the oil level is lower than the low oil level, the return pump will be emptied, resulting in a decrease in the capacity of the return pump, resulting in poor oil return.
For this reason, in the case that it is difficult to effectively improve the grinding roller seal and the grinding roller lubrication system, our company starts from controlling the oil level in the grinding roller, and adds a high temperature resistant liquid level sensor to the grinding roller. Achieved very good results. The liquid level sensor lead mounted on the grinding roller bearing gland is taken out from the grinding roller shaft, and a three-way electromagnetic ball valve is added to the oil station oil supply line, and the normally open point is connected with the grinding roller oil supply line, often The closed point is connected to the return line.
When the liquid level in the mill is higher than the upper limit, the electromagnetic ball valve will transfer the oil supplied from the oil supply pump to the return line; when the liquid level lower limit is reached, the electromagnetic ball valve will be switched to the oil supply line; Control of the lubricating oil level in the grinding roller. As the grinding roller rotates and undulates up and down, the liquid level changes up and down. When the value is taken, we only collect the small value in the liquid level sensor for 5s, which can reflect the actual situation of the liquid level.
By adding the liquid level sensor, it can be ensured that the grinding roller does not leak oil when the grinding roller seal wears and the oil return is not smooth; the liquid level change in the grinding roller can also be monitored in real time, so that the oil level can be known and controlled, The control of grinding has taken another step towards intelligence.