JPS59173145A - Control of tower type crusher - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for controlling the operation of a dry type crusher (tower mill).

For example, a dry type crusher is T7. Tokuko Showa 39-5584
This is a known pulverizer that was also disclosed in No. ``Dry Type Attrition Grinder''. As shown in Figures 1 and 2, this crusher has a shaft at the center of a closed apposition 1, a screw 3 is attached to this shaft, and a card motor 4 directs the screw 3 in the direction to lift the contents. Rotate it. The feed ore is quantitatively fed into the crusher by a rotary valve 5.

Although pulverization is sometimes carried out using feed minerals, the pulverizer is usually filled with a pulverizing medium such as steel balls.

The fed material to be crushed is lifted together with the crushing media by the screw 3 and falls along the wall, during which time
The material is ground by the grinding action of grinding the grinding medium and the material to be ground. Hereinafter, this pulverized product will be referred to as powder.

The powder is discharged to the outside of the pulverizer, but in the pulverizer shown in FIG. The airflow is circulated from the blower 6 to the crusher again. In the pulverizer shown in FIG. 2, the powder is extracted from the bottom of the pulverizer through a slit (not shown) by the airflow from the blower 6, discharged outside the pulverizer, and collected by a bag filter 7. Ru.

In a formal crusher, even if a fixed amount of feed ore is supplied by the rotary valve 5, the amount of powder discharged from the crusher, that is, the amount of product, does not become constant over time, and therefore the filling amount of the material to be crushed in the crusher may decrease or increase. Furthermore, the fineness of the powder may vary. When the filling amount in the crusher increases and reaches a maximum, continuous operation is no longer possible.

Conventionally, increases and decreases in the filling amount of materials to be crushed in such a formal crusher were detected by measuring the wind pressure at a certain point in the blower duct in a crusher equipped with an air circulation blower as shown in Figure 1.
The wind pressure detection end is often blocked by objects to be crushed, and the gap between the grinding media in the crusher is often clogged with objects to be crushed, resulting in large pressure fluctuations, so the detected wind pressure is used for operation control. There was nothing I could do. Further, in the crusher shown in FIG. 2, there was no suitable method for detecting an increase or decrease in the amount of filling in the crusher. That is, in the conventional dry type crusher, there is no method for accurately detecting an increase in the amount of filling in the grade crusher, and an appropriate control method for operating the grade crusher under optimal conditions has not been known.

The present invention is intended to solve the above-mentioned problems, and its gist is a method for controlling the operation of an informal crusher consisting of a closed apposition, a sleeve rotating at its center, and a screw attached to the shaft. A method of controlling a formal crusher is characterized in that a noise detector is disposed near the crusher, and the amount of ore fed is controlled based on the output of the detector.

The present inventors previously tested a method for controlling the operation of a so-called ball mill, which is a horizontal cylinder or cone filled with steel balls, by detecting the sound emitted by the ball mill. For mills that grind cement raw materials and cement barrels, a sound level meter (Japanese Industrial Standards) is used to detect the grinding noise of the mill and determine the amount of material to be ground that remains (fills) in the mill and the For example, acoustic data corresponding to the crushing situation can be applied to the amount of ore fed to the mill.
- This method attempts to control the operation of the mill by pumping. As a result of the test, with ball mills, it is possible to detect the extreme case where the mill is full of materials to be crushed and there is no sound of the balls hitting by just detecting the noise level, but Although it is difficult to detect subtle changes such as the amount of pulverized material remaining or the degree of pulverization, acoustic frequency analysis shows that it is possible to understand the situation inside the mill to some extent by selecting an appropriate frequency band. I knew that.

In view of the above experience, the present inventors focused on the sound emitted by a grade crusher, and as a result of testing a method of utilizing changes in the increments to control the operation of a grade crusher, the inventors found that they could use a simple sound level meter without performing frequency analysis or the like. It was confirmed that the data measured by the method alone can be used sufficiently as operational control data.

In other words, according to a noise test of a formal crusher, it was found that the only way to detect significant noise for use in acoustic control was due to changes in the contact sound between the balls and the inner surface of the shell.

In a ball mill, when the amount of material to be ground is small, significant detection is obviously made due to the contact between the ball mill and the inner surface of the shell, but as the amount of material to be ground in the ball mill increases, it may not fill the ball layer sufficiently. Even if there is no ball layer, it tends to stay at the bottom of the pole layer, near the inner surface of the shell and shell, so the sound generated between the ball layer and the shell is greatly reduced.
The sound caused by the collision of balls in the ball layer with no material to be crushed is also greatly reduced.

Therefore, even if the amount of material to be crushed in the ball mill is increased further, it will be very small while the sound level is changing.
Controlling for significant differences was not possible.

However, in the case of a formal crusher, when the amount of material to be crushed in the crusher increases, the retention area gradually rises from the bottom of the crusher upwards, so the upper layer of the crushing media is in contact with the crushing media and the inner surface of the shell. It has been confirmed that the contact area increases and decreases, and that extremely sharp acoustic changes occur due to changes in the contact area.

Examples of the present invention will be described below.

FIG. 3 is a control system diagram of the method of the present invention.

A Japanese Industrial Standards "indicating sound level meter JIO" was placed 5 meters apart horizontally from the grade crusher to detect the noise level (A characteristic) L and input it to the controller 11. Set the noise level setting value S, and set this setting value S.
The rotation speed of the rotary valve was controlled by the deviation between the measured value and the measured value. The rotary valve 5 that controls the amount of ore to be fed is made variable speed, and the output of the above-mentioned controller is input to the rotary valve rotational speed changing device. That is, automatic control was carried out in which the noise level L of the formal crusher was used as a controlled variable, and the rotational speed RV of the rotary valve, which was kept constant, was used as the manipulated variable. The noise level in the preliminary test was 95 phon (A) when the material to be crushed was not supplied into the crusher and only steel balls were used for dry firing, and the noise level increased as the amount of material to be crushed in the crusher increased. When the object to be crushed exceeds the upper surface level of the crushing medium by 20 cm, it becomes 84 phon (A), and during this time the noise level gradually decreases.

In this example, as a result of performing the control described in -H as 5-87 Hon (A), it was possible to continue stable operation at a high grinding efficiency without causing hunting, etc., and the grinding capacity was improved compared to the conventional method. It increased by about 5%, and the basic unit of grinding media decreased by about 3%.

In order to avoid the influence of background noise, it is desirable to use a directional microphone, for example, when another crusher is operating in the crusher room or when there is noise from other noise-generating machines. A simple sound level meter may be used as the sound level meter.

As mentioned above, in the case of a formal crusher, the sound emitted by the crusher during crushing does not require the selection of sound waves in a specific frequency band, and the noise level measured by a sound level meter is the same as that of the crushed material inside the crusher. It clearly indicates the filling amount of the material, and the crusher can be operated automatically just by using this signal. It is also possible to use the output of the sound level meter as a signal given to an alarm circuit.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory diagrams of a dry grade crusher, and FIG. 3 is a control system diagram of the method of the present invention. 1... Closed apposition, 2... Cyclone, 3... Screw, 4... Guard motor, 5... Rotary valve, 6... Blower, 7... Bag filter, 1
0...Sound level meter, 11...Controller □ Applicant: Mitsubishi Mining and Cement Co., Ltd. Agent Patent attorney: Yoshio Kosugi Figure 1, Number 2, Third cause

Claims (1)

[Claims] 1. In a method for controlling the operation of a formal crusher consisting of a closed apposition, a shaft rotating at its center, and a screw extending through the shaft, a noise detector is disposed near the crusher, and a noise detector is installed near the crusher; A method for controlling a formal crusher, characterized by controlling the amount of ore fed by output.