JPH0137972B2 - - Google Patents

Abstract

1. A bow mill with vertical axis, the bowl rotating relative to means (4) pressing the material against the surface of the bowl (1) and being controlled by hydraulic cylinders (9), with a control and adjusting circuit depending on the material to be ground, comprising a means (20) for indicating the rate at which materials is being fed into the mill and a means (24) for indicating the pressure of the hydraulic fluid in the cylinders, characterized in that it further comprises a means (22) for indicating the power absorbed by the mill, a means (21) for indicating the height of the layer of material between the pressing means and the bowl, and (19, 17) for sensing the data of the indicating means in order to maintain a variation of the height of the layer of material according to the throughput rate of the mill according to a predetermined linear law between 30 % and 100 % of the maximum throughput rate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bowlmill having a vertical axis. In the bowl mill of the present invention, the bowl rotates relative to the pressing means for pressing the material to be crushed onto the surface of the bowl, and the pressing means is controlled by the control means depending on the material to be crushed. and includes means for detecting the distance between the pressing means and the bowl, ie the height of the material layer, and means for detecting the amount of material supplied.

French patent application No. 2424065 in the name of the applicant discloses a mill with a rotating bowl having a vertical axis and a roller with pendulum suspension which is pressed against the material to be ground by a hydraulic cylinder. The mill of that patent includes a regulating control circuit that can vary the pressure of the rollers depending on the material to be milled or according to a predetermined law during milling, and furthermore includes a control circuit of the hydraulic cylinders. It includes pressure and position sensing means and a hydraulic cylinder pressure regulating device responsive to the data provided by the sensing means to determine the material to be crushed and optionally the pressure in the hydraulic cylinder according to a predetermined law.

However, it often occurs that materials are processed by such mills that are subject to changes in properties such as particle size and brittleness during one operating cycle of the mill. Since it is not possible to predict the point at which the material to be ground will reach virtually new properties in the mill, the mill may continue to operate under extremely unfavorable conditions. In particular, when the properties of a less brittle material change to become a more brittle material, there is a risk that the roller may become stuck in the material and become unable to come out. This may cause vibrations or even an abrupt stop of the mill's operation. Therefore, the mill cannot resume operation unless the rollers are removed and the roller positions are readjusted. Conversely, if a more brittle material changes to a less brittle material, the less brittle material will not be sufficiently ground until the mill realizes that it is not working well and changes the mill settings. It turns out.

The object of the invention is to eliminate the drawbacks mentioned above and to be able to automatically adapt to the properties of the material to be ground as they change during processing in the mill, so that the properties change over time. To provide a bowl mill that can completely prevent accidents and stoppage of operation even when processing changing materials.

The mill of the present invention is characterized by a means for detecting the power absorbed by the mill, a means for detecting the feed amount of material introduced into the mill, and a function of the feed amount of the mill in response to the data of the two aforementioned detecting means. and means for maintaining the height variation of the material layer according to a predetermined law.

The predetermined law for adjusting the height of the material layer is preferably linear in the range from 30% to 100% of the maximum feed volume.

Based on the attached drawings, which respectively show an embodiment of a coal crushing mill with a rotating bowl and rotating rollers according to the invention and an embodiment of the regulation law of the height of the coal seam as a function of the amount of feed to be processed. Specific examples of the present invention will be described below in a non-limiting manner.

In FIG. 1, a rotary bowl mill 1 having a rotating shaft 2 has an inclined edge 3 forming a guide path for tapered rollers, only one of which is shown, reference numeral 4. The roller 4 is carried by an axle 5 which rotates about a pivot axis 6. End 7 of shaft 5
is the ram 8 of the hydraulic cylinder 9 with the piston 10
It is pivoted to.

The coal to be crushed stored in the hopper 11 is supplied to an endless conveyor belt 12. The drive roller 13 of the belt 12 is driven by a motor 14. The scraper 15 aligns the coal on the belt to a constant thickness. The coal on the belt falls into a vertical chute 16 that opens above the axis of the mill. The coal is then dumped onto the periphery of a rotating bowl;
It passes between the roller and the guideway and is crushed.

The pressure in the hydraulic cylinder 9 is controlled by a control device 17. Device 17 includes, among other things, a working fluid tank, a pump, and a pressure regulator, all of which are known devices and are therefore not shown. The control device 17 is connected to the hydraulic cylinder 9 by a conduit 18.
and to the control and regulation assembly 19.

A control and regulation assembly 19 is arranged in the vicinity of the axis 5 of the roller 4 and a sensor 20 for measuring the amount of coal feed determined by the rotational speed of the roller 13 and the coal feed rate between the roller and the guideway. A signal indicating the coal feed amount and the height of the coal seam, respectively indicated by a sensor 21 measuring the seam height, is received. Assembly 19 is further connected to a sensor 22 which is connected to the mill's shaft drive motor 23 and which measures the power absorbed by the mill. Finally, it is also connected to a sensor 24 which measures the liquid pressure acting on the ram 8.

A control and regulation assembly 19, for example a microprocessor, regulates the pressure applied to the ram 8 via the control device 17 in accordance with the coal feed quantity indicated by the sensor 20, which regulation The height of the coal seam corresponding to the linear relationship between the coal feed amount D (% of the nominal feed amount) and the height H (mm) of the coal seam shown in the figure is measured by the sensor 21. . Said linear relationship is valid for feed quantities ranging from 30 to 100% of the nominal feed quantity, and the height of the coal seam is e.g.
It ranges from 15 to 25mm.

Control and regulation assembly 19 is further responsive to the power absorbed by the mill as indicated by sensor 22;
Sensor 24 is responsive to the pressure of the rollers acting on the coal to be crushed within the mill. The assembly adjusts the thickness of the coal being crushed and the amount of coal feed between the rollers and the rotating bowl as a result of the respective changes in the height of the coal seam, the amount of coal feed, the power absorbed by the mill and the working pressure of the rollers. Each parameter is balanced so that a linear relationship similar to that shown in FIG. 2 is maintained between them. Further, the distance between the rollers and the rotating bowl is increased so that the thickness of the coal seam increases when either the amount of coal feed or the power absorbed by the mill increases. Furthermore, the sensors 22 and 24 may be connected to a display or graphic recording device and, if necessary, to an emergency stop means (not shown).

Although the mill described with reference to FIG. 1 represents a preferred embodiment of the invention, various modifications may be made without departing from the overall scope of the invention, and several means may have technically equivalent functionality. It will be understood that other means of accomplishing this may be substituted. In particular, it is possible to use rolling rollers, balls, etc. in place of the grinding roll. Coal feeding to the mill may be effected by means other than endless conveyor belts.
It is also possible to configure the mill so that the bowl is fixed and the grinding means are movable.

The device according to the invention is used in particular for the grinding of coal, but is also suitable for grinding other materials such as ores, phosphates, etc.

[Brief explanation of drawings]

Figure 1 is an illustration of the mill and the mill control device according to the height of the coal seam during crushing, and Figure 2 is a graph showing the linear relationship between the coal feed amount and the height of the coal seam in the mill. be. 1... Bowl mill, 4... Roller, 5... Mandrel, 8... Ram, 9... Hydraulic cylinder, 10...
Piston, 11...Hopper, 12...Belt, 1
3... Drive roller, 14... Motor, 15... Scraper, 16... Shoot, 17... Control device, 19... Control adjustment assembly, 20,2
1, 22, 24...Sensor, 23...Shaft drive motor.

Claims (1)

[Scope of Claims] 1. A bowl, a supply means for supplying the material to be crushed into the bowl, and a supply means disposed above the bowl, for directing the supplied material toward the surface of the bowl. A pressing means for pressing the material, a rotating means for rotating the bowl to crush the material, a first detection means for detecting the power of the rotating means, and a first detecting means for detecting the power of the rotating means; a second detection means for detecting the amount of material supplied; and a second detection means disposed near the pressing means, the second detection means is arranged in the vicinity of the pressing means, and a contact between the pressing surface of the pressing means and the surface of the bowl at a portion where the pressing means presses the material. A third detection means for detecting a distance is connected to the first, second and third detection means and the pressing means, and the amount of the supply of the material and the power of the rotation means are and a control means for controlling the pressing force of the pressing means so that the distance increases when at least one of the pressing forces increases. 2. if the supply rate of said material of said supply means is between 30% and 100% of the maximum supply rate of said supply means, said distance increases in direct proportion to the supply rate of said material of said supply means; Claim 1
Baur mill as described in section.