SU581988A1 - Method of automatically monitoring the filling of a self-disintegration drum mill - Google Patents

Description

I

The invention relates to methods for monitoring the progress of fine grinding of materials and can be used in cement, mining, chemical and other industries of the industry with automatic control and regulation of filling of self-grinding drum mills.

Known methods for monitoring the filling of drum mills, based on the measurement of circulating load 1.

However, with these methods, there is insufficient interference resistance, caused by a significant effect on the controlled values of interference, which characterize the particle size distribution of the intramill load, the grindability, the density of the material of the load, etc.

Also known is the closest to the invention a method for automatically controlling the filling of a drum mill, which includes measuring the active power of the Mill Motor and extracting low-frequency oscillations 2 from the signal of the spectrum power.

The disadvantages of this method are low noise immunity and accuracy of measurements, which is caused by a significant effect on the components of the amplitude-frequency characteristic of the selected spectrum and of the low-frequency oscillations of the active power of the granule mill of the material of the external load.

The purpose of the invention is the increase in accuracy and a high stability.

This is achieved by the fact that with the method of automatic control of the filling of the drum mill it is self-chopped, which includes measuring the active power of the mill motor and extracting low-frequency vibrations from the power signal of the spectrum, before measuring the active power of the motor, increase the power fluctuations at a frequency equal to the mill speed of the mill unbalance the drum of the mill, and after determining the spectrum of low-frequency oscillations, the harmonic composition is extracted from it L moiety at a frequency equal to the angular speed of the mill drum is measured by its amplitude} largest kotoro.y judged on the degree of filling of the mill drum.

The drawing is a diagram of the device that implements the proposed method.

An unbalanced load 4 is attached to the drum of the mill 1 driven in through the reducer 2 of the engine 3. The signal from the active power sensor of the drive motor 5, which is separated from the low-frequency oscillation power signal, is fed to the DC compensation unit and input resonant filter 7, the latter selects from the low-frequency spectrum a harmonic component with a frequency equal to the angular velocity of rotation of the mill drum, the magnitude of which is recorded by the measuring instrument 8. Boron is graduated in percentage volume fill of the drum mill. The change in amplitude depends on the change in friction force in the mill support bearings of the mill, which is a function of the weight of the mill drum and the weight of the mill feed.

Thus, with a constant drum weight and a constant friction coefficient, the change in amplitude is proportional to the change in the amount of material and drum in the mill.

Claims (2)

Invention Formula A method for automatically controlling the filling of a self-grinding drum mill. including measuring the active power of the mill engine and extracting low-frequency oscillations from the signal of the power generator, characterized in that, in order to increase the motor's active power, the power fluctuations at a frequency equal to the angular velocity of the mill drum are measured by creating an artificial unbalance the drum of the mill, and after the determination of the spectrum and of the low-frequency oscillations, the harmonic component is extracted from it with a frequency equal to the angle ti mill drum, an amplitude of it is measured, but the value is judged on the degree of filling of the mill drum. Sources of information taken into account in the examination 1- USSR Author's Certificate No. 527205, cl. B 02C 25/00, 1975. 2. USSR author's certificate No. 460067, cl. B 02C 25/00, 1974.