JPS59213458A - Operation 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 dry type tower mill equipment.

The dry type grinder is a known grinder disclosed, for example, in Japanese Patent Publication No. 39-5584 ``Dry Type Grinding Mill''. As shown in Figures 1 and 2, this crusher has a shaft at the center of the closed apposition l, a screw 3 is inserted into this shaft, and a geared motor 4 directs the screw 3 in the direction in which it lifts the contents. Rotate it. Ore feeding device 5
For example, a rotary valve is used to supply a fixed amount. The supplied materials to be crushed may be crushed by themselves, but usually a crushing medium such as steel balls is filled in the crusher, and the materials to be crushed are held together with the crushing medium by the screw 3. The material is crushed and falls along the wall, and during this time, the material is crushed by the grinding action caused by the grinding medium and the object to be crushed. The thus crushed product is discharged from the crushing tower,
Necessary products are classified and collected and sent to the product storage area.

In the equipment shown in Fig. 1, there is a wind classifier inside the crusher, and the material to be crushed is blown up by the air blown from the lower end of the same grade, and the material to be crushed is classified, and those with a certain particle size or less are discharged with the wind and reach cyclone 2. will be collected. Therefore,
Although it is preferable that the crushed material having a particle size smaller than the target particle size can be recovered as a product, blow-through may occur due to the air flow blowing inside the crusher, and the operating conditions of the crusher become extremely unstable, resulting in unstable operation. There is a problem.

In the apparatus shown in Fig. 2, the material to be crushed is extracted by the downward flow of air extracted from the inside of the crusher by the blower 6, and the material to be crushed is recovered by the cyclone 2 and the bag filter 7 in an open circuit system, so that it is possible to reduce the particle size to less than the target particle size. - The crushed material is also collected as a product, which is not only inconvenient, but also prevents the downward air flow from passing through the part where the crushed material is densely packed in the apposition bottom, making the operation unstable and reducing the amount of product. There are drawbacks such as large fluctuations in product particle size.

As shown in Figures 1 and 2, the material to be crushed is discharged from the crusher by the airflow from the blower, so even if the amount of feed ore supplied to the material to be crushed is constant, the discharged amount will not add up. Due to changes in the filling amount and packing density of the material to be crushed into the gaps between the grinding media, the ventilation resistance inside the crusher fluctuates greatly, and the amount of material to be crushed is not only unevenly discharged, but also sometimes There are disadvantages such as continuous operation becoming impossible due to an abnormal increase in the amount of filling, and the power of the blower increasing abnormally.

In order to eliminate this drawback, the non-pulverizers have proposed a device that extracts and transports the material to be crushed from the lower end of the same level using a mechanical extractor without using any ventilation as one of the lower extraction methods. However, in this case, the method of the present invention maintains the maximum grinding efficiency and reduces wear and tear on the grinding media.
After extensive research on dF, we developed the most appropriate operation control method for a formal crusher equipped with a mechanical drafting device for the materials to be crushed.

The present invention will be explained below with reference to the block diagram of FIG. The material to be crushed is supplied to the ore feeding device 5, for example, with variable speed.

The material is supplied to the crusher by a feeder (supply Etb), and the supply amount is adjusted in response to fluctuations in the level a of the material to be crushed within the closed cylinder l. It is desirable to automate the adjustment at this time, but it may also be done manually. Note that for detecting the level within the apposition of the object to be crushed, it is preferable to use an ordinary sound level meter 8 installed near the outer surface of the apposition, which has been proposed separately by the present inventors. The material to be crushed is extracted from the bottom of the tower by a variable speed extractor 11, for example, a variable speed drive gun type screw conveyor (extraction c), and then passed through a subsequent transporter 12 (transport amount d) to a classification device 13. to go into. The transportation amount d is measured by a measuring device 9. The products classified by the classification device 13 are sent to a storage area (not shown) (delivery amount g), and the products to be crushed that do not meet the classification standards are returned to the crusher (return &tf). Here, the transporter 12 is suitably a closed type such as a packet elevator, and one capable of transporting a total transport amount d of A1σ. Extraction device 11 and transportation4. Although some storage chambers for materials to be crushed may be provided between the crushing material and the crushing material ff12, as a general rule, the extraction amount C and the transportation amount d are equal during steady operation. That is, the present invention aims to make the crushed material collection circuit a closed circuit, keep the level of crushed materials in the same class constant a, and operate with the highest crushing efficiency. When the transportation amount d, that is, the extraction kc is controlled according to the appropriate values of the particle size of the product, the delivery amount, etc., the level a of the crushed material in the crusher is displaced in response to this, and then the displacement of the crushed material level a is It detects this and controls the supply amount to keep it constant. In this way, the material to be crushed can be allowed to stay in the grinding media packed bed in the grinder for just the desired residence time, and the performance of the classifier 13 can also be kept constant. In other words, it is possible to maintain the crushing efficiency of the crusher at the highest level and to maintain the overall operating conditions from ore feed to products in the best condition at all times.

Note that the setting conditions of individual machines, such as the size of the grinding media, the filling amount, the setting of the transportation amount d, etc., differ depending on the type of material to be crushed and the target particle size for crushing, etc., so it is necessary to understand these basic conditions in advance. By setting the optimum conditions and implementing the present invention, a formal crusher can be operated at maximum efficiency.

EXAMPLE The method of the present invention was carried out in a formal crusher having an operation control system as shown in FIG.

The main specifications of the equipment are: Equal diameter: 1170mmφ Height: 3500mmH Screw diameter: 900mmφ Grinding media: 17mmφ Steel ball extraction chute: 45° inclination Extraction device: Variable speed motor driven gun type screw conveyor transportation device: Bakent elevator Classification device: Air flow classification separator Feed device: Variable speed motor driven rotary valve Material to be crushed: Blast furnace slag tower Internal material to be crushed Level detector: Ordinary sound level meter The results of implementation were as follows. Depending on the condition of the final product obtained by classification, the powder degree adjustment device of the classifier is adjusted to provide the appropriate amount of acid.
When continuous operation was carried out while keeping the withdrawal Ic from the crusher constant, the powder level in the tower changed in response to the fluctuation in the withdrawal amount. Since we were able to adjust the supply amount, we were able to smoothly control the overall operation.

Specifically, the Blaine value was set at 1 in the 24-hour operation test, and the powderiness target was 4000 cm'/g, but the actual result was 390 cm'/g.
The supply rate fell within the range of 0-4100 cm'/g (1), and the supply amount fluctuation remained within a range of ±3% of the average value during that period, remaining almost constant, and the level of the crushed material in the column was The changes were within a range that had little effect on the grindability, demonstrating that this method is extremely reliable in terms of stable operation. In addition, to manage the product Blaine value this time, sampling was performed every 15 minutes, but based on actual results, it was determined that if sampling was performed every few hours, it would be -1-minute.

[Brief explanation of drawings]

Figure 281 and Figure 2 are explanatory diagrams of a dry type crusher.
There are 1 types, all of which discharge the crushed material using an air flow method. Third
The figure is a block diagram of an embodiment of the invention. ■...Closed appositive 2... Cyclone 3...
・Screw 4...Card mork 5...Ore feeding device 6...Blower 7...Bag filter
8... Ordinary sound level meter 9... Measuring device 11...
- Extracting device 12...Transporting machine 13...Classifying device a...Retention height of the crushed material in the same grade b...Amount of crushed material supplied C...Extracting star d...Transport amount f. ...Return mouse g...Product output amount Applicant Mitsubishi Mining Cement Co., Ltd. Agent Patent attorney Yoshio Kosugi Figure 1↓1゛ko 2 Figure Silk 3 Figure 9A-

Claims (1)

[Claims] ■ A closed apposition, a shaft that rotates at its center, a screw attached to the shaft, a material supply device installed at the top of the apposition, and a mechanical material extraction device installed at the bottom end of the apposition. In a formal crusher consisting of a crusher, a classification device is installed in the crushing material collection circuit to return oversized materials to the crusher, and the amount of crushed materials taken out is controlled so as to keep the amount of crushed materials supplied to the classification device constant. A method for controlling the operation of an informal pulverizer, characterized in that the supply amount of the material to be crushed is controlled so as to keep the residence height of the material to be crushed within a certain range.