JPS6331260B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a dry tower mill.

The dry tower type pulverizer is a known pulverizer disclosed, for example, in Japanese Patent Publication No. 39-5584 ``Dry Tower Type Grinding Mill''. As shown in Figures 1 and 2, this crusher has a shaft at the center of a closed circular column 1, and a screw 3 is attached to this shaft, and a geared motor 4 lifts the contents of the screw 3. Rotate it in the same direction. Ore feeding is rotary valve 5
Quantitatively supplied into the crusher by Although pulverization is sometimes carried out using feed minerals, usually a crushing medium such as steel balls is filled in the crusher, and the fed material to be crushed is lifted up by the screw 3 together with the crushing medium. , it falls along the wall, and during this time it is crushed by the grinding action of the grinding medium and the object to be crushed. Hereinafter, this pulverized product will be referred to as powder.

In conventional tower-type pulverizers, all means for discharging powder out of the pulverizer utilize ventilation. That is, in the crusher shown in FIG. 1, the particles are discharged from above along with the upward air flow inside the crusher caused by the blower 6, and are collected by the cyclone 2. Airflow is by blower 6
Then it goes to the crusher again and is circulated. In the pulverizer shown in FIG. 2, the powder passes through a slit from the bottom of the pulverizer, is extracted by the airflow from the blower 6, is discharged outside the pulverizer, and is collected by a bag filter 7. In the above-mentioned conventional tower type crusher, the ventilation resistance inside the crusher varies greatly depending on the filling amount or packing density of the material to be crushed into the gaps between the crushing media, and as a result, the supply amount of the material to be crushed is not constant. However, the amount of powder discharged was not constant, and sometimes continuous operation was impossible due to an abnormal increase in the filling amount, or the power of the exhaust blower caused abnormal fluctuations.

The inventors of the present invention have conducted extensive research in order to improve these drawbacks and have developed a part-extracting type crusher that does not utilize ventilation, as shown in Fig. 3.

The present invention aims to keep the amount of material to be crushed filled in the gap between the crushing media in a closed circular column constant, by mechanically extracting the powder from the lower part of the inner column without using ventilation, and The objective is to be able to arbitrarily control the amount of powder extracted.

Next, the present invention will be explained with reference to the drawings. FIG. 3 is a partially sectional side view schematically showing an embodiment of the present invention. There is a screw 3 in the closed circular column 1 that generates an upward propulsive force, and it is rotationally driven by a geared motor 4. The circular column 1 is filled with grinding media such as steel balls as necessary. The ore is supplied in a constant quantity through a rotary valve 5.

The material to be crushed is ground by the crushing medium and turned into powder, which gradually moves to the lower part. In the present invention, a lower powder outlet 9 is provided at the side of the lower end of the closed circular column 1, and this outlet 9 is provided with a transporter 10 or a rotary valve 11 that can arbitrarily control the amount of powder extracted. Transport aircraft 1
The rotary valve 11 is driven by, for example, a variable speed motor whose rotational speed can be adjusted arbitrarily, and a screw conveyor or the like is suitable as the transport device 11, and among them, a so-called gun screw conveyor with high airtightness, Alternatively, a gradual pitch type screw conveyor in which the screw pitch gradually decreases in the future is optimal. 3a shows an example equipped with a screw conveyor 10, and FIG. 3b shows an example equipped with a rotary valve 11 and sent out by a separate transporter 13. FIG. 3c shows an example in which the inclination angle is set as large as possible so that the inner surface of the sealed duct 12 connecting the powder outlet 9 and the transporter 10 or the rotary valve 11 functions as a chute. In conventional tower-type crushers that use ventilation to extract powder from the bottom, the powder is discharged by blowing in or sucking out air using a blower, so there was no problem of powder accumulating in the duct, but the present invention eliminates the problem of powder accumulation in the duct. As a result of using a system in which the powder is directly mechanically extracted from the circular tower through a closed duct without using any other method, the phenomenon of powder stagnation or, in the worst case, blockage, may occur in this duct. This phenomenon is caused, for example, as a result of the fluidity of the powder being significantly inhibited when the particle size structure of the powder is over a wide range. In such a case, it is preferable to make the duct 12 slope at an angle of 45 degrees or more so that the material can be extracted with good fluidity.

Next, the effects of the embodiment of the present invention shown in FIG. 3c will be explained. The main specifications of this example are as follows: Round tower Inner diameter: 1170mmφ Height: 3500mmH Screw diameter: 900mmφ Slit size: 20mm Grinding medium: 27mmφ Steel ball extraction port duct inclination: 45° Extraction device: Variable speed motor-driven gun Screw conveyor Materials to be crushed: Blast furnace slag Materials to be crushed Feed amount: 1.7 t/h When operating a tower-type crusher with specifications of 1.7 t/h or more while extracting powder using a mechanical extraction device, the powder was discharged smoothly. , no trouble at all,
Amount of extraction and level (height) of crushed material in the tower
As a result of operating the machine with various changes, it was found that it was easy to maintain a constant operating state, and the crushing capacity could be increased by up to 70% compared to a conventional crusher equipped with a wind-powered extractor. Ta.

[Brief explanation of the drawing]

Figures 1 and 2 are partially sectional side views of a dry tower type crusher, both of which discharge the material to be crushed using an air stream. Figures 3a, b and c show partially sectional side views of an embodiment of a bottom drawer tower crusher according to the invention. 1... Closed circular tower, 2... Cyclone, 3... Screw, 4... Geared motor, 5... Rotary valve for ore feeding, 6... Blower, 7... Bag filter, 9... Powder extraction port, 10 ... Transport machine (screw conveyor), 11 ... Rotary valve, 1
2... Duct (chute), 13... Transport aircraft.

Claims (1)

[Claims] 1. In a tower-type crusher consisting of a closed circular column, a shaft that rotates at the center, a screw attached to the shaft, and a device for extracting the crushed material at the bottom of the circular column, the crushed material is placed on the side of the lower end of the closed circular column. Provide an outlet for the
A tower-type crusher characterized in that the extraction port is provided with a mechanical extraction device that can arbitrarily control the extraction amount.