What about oil leakage from the vertical grinding roller?

Oil leakage problem of vertical grinding roller often appears in the cement factory with vertical grinding mill, how to do the oil leakage of vertical grinding roller?

This is the difficult problem that perplexes the mill manufacturer all the time.

Oil spills not only pollute the environment, but also increase production costs.

1. Cause analysis of oil leakage of vertical grinding roller

There are many causes of oil leakage of vertical grinding roller, which can be summarized into two main points:

First, the reason for roller seal.

At present, the vertical grinding roller seal mainly adopts 3 skeleton lip seal, 1 dust proof, 2 oil proof.

However, the working environment of the vertical mill is very bad, which belongs to the working conditions of high dust, high temperature and impact vibration.

And seal replacement is very difficult, the need to roll over, the roller from the rocker arm removed, its work time, labor, maintenance cost is high.

Second, the lubrication system of grinding roller is not smooth.

When the grinding roller is working, the bearing will generate some heat and be in a high temperature environment. Therefore, it generally adopts the method of thin oil circulation lubrication, which can take away the excess heat and ensure that the bearing is in a normal temperature range.

But in practice, if the return of oil is not free, the oil level in the roller will rise, and finally from the oil seal and air out.

There are the following reasons for the poor oil return of the grinding roller lubrication system:

(1) temperature.

When the grinding is started or the ambient temperature is too low after the shutdown, the internal temperature of the grinding roller and the temperature of the oil return pipe are not high, because the vertical mill generally adopts the lubricating oil with a viscosity of about 320mm2/s, and the flow is poor, so the oil return is not smooth.

(2) reasons for resistance.

The lubrication of the vertical mill is generally the way of centralized lubrication, including the roller lubrication station and other oil stations are centrally placed in a room, the distance from the vertical mill lubrication point is generally far, so the pipe resistance is greater, resulting in oil return.

(3) reasons for pipeline intake.

In fact, it is impossible to achieve the same amount of oil supply and oil return, so in order to ensure that the oil level is not too high, the amount of oil return is greater than the amount of oil supply.

The return oil is located at the lowest oil level that needs to be guaranteed. When the oil level is lower than the lowest oil level, the return oil pump will be sucked empty, resulting in the return oil pump capacity decline, return oil is not free.

2. Solution to oil leakage of vertical grinding roller

Therefore, in the case that it is difficult to effectively improve the grinding roll seal and lubrication system, the vertical mill manufacturer starts from controlling the oil level in the grinding roll and adds a high temperature resistant liquid level sensor in the grinding roll, as shown in figure 1.

A good result was achieved.

The lead wire of the liquid level sensor installed on the pressure cover of the roller shaft is extracted from the roller shaft, and a three-way solenoid ball valve is added on the oil supply pipeline of the oil station. The normally open point is connected with the oil supply pipeline of the roller, while the normally closed point is connected with the return pipeline.

When it is found that the liquid level in the mill is higher than the upper limit, the solenoid ball valve will transfer the oil supplied by the oil pump to the return pipe line, and when it reaches the lower limit of the liquid level, the solenoid ball valve will be converted to the oil supply line, so as to achieve the control of the lubricating oil level in the mill roll.

As the grinding roller rotates and fluctuates when working, the liquid level changes back and forth. When taking the value, we only collect the minimum value within 5s of the liquid level sensor as the actual liquid level value, so as to reflect the real situation of the liquid level.

By adding liquid level sensor, it can ensure that the grinding roller does not leak when the seal is worn and the oil return is not free.

It can also monitor the change of liquid level in the grinding roller in real time, so that the oil level can be known and controlled, which makes the control of the vertical mill step forward to the direction of intelligence.