Polygon-shaped mill with air nozzles

Abstract

The proposed solution provides a mill designed for crushing steel slag or combustion ash in such a way that metals and slag materials can be separated. The mill is formed of a casing (1), a cover (2) and a base (3) and within the mill there is a crushing element by means of which the steel slag and combustion ash is breakable and that the material is feedable to the centre of a rotor wherefrom, due to centrifugal force, it becomes ejected onto walls of the casing (1) of the mill, wherefrom it drops out via outlet apertures provided in the base (3). The mill is, in cross section, polygon-shaped. At comers of the cover (2) of the mill, there are compressed air nozzles (4) extending through the cover, via which nozzles blows of compressed air are directable onto the comers within the mill and remove difficult, moist material that has adhered to the walls during production and while the mill is rotating.

Description

[0001] POLYGON-SHAPED MILL WITH AIR NOZZLES

[0002] An object of this invention is a mill designed for crushing steel slag or combustion ash in such a way that metals and slag materials can be separated, and which mill is formed of a casing, a cover and a base and within the mill there is a crushing element by means of which the steel slag and combustion ash is breakable and that the material is feedable to the centre of a rotor wherefrom, due to centrifugal force, it becomes ejected onto walls of the casing of the mill, wherefrom it drops out via outlet apertures provided in the base.

[0003] A mill representing the prior art has been disclosed, for example, in Finnish patent application 20180003. See also Fig 1 of this application. Tests and mill use have proven that in terms of quality, the crushed material is just what was hoped of the mill. The mill has one drawback. If the crushed material is not completely dry, but has even the slightest moisture, the material tends to become stuck to inner walls of the mill.

[0004] The purpose of this invention is to overcome the above-mentioned drawback. The mill according to the invention is characterized in that the mill is, in cross section, polygon-shaped and that, at comers of the cover of the mill, there are compressed air nozzles extending through the cover, via which nozzles blows of compressed air are directable onto the comers within the mill and remove difficult, moist material that has adhered to the walls during production and milling. Especially if the relative moisture percent of the ground material is high, the material becomes stuck and packed tightly to the walls, and for this purpose the mill according to the invention removes the material from the walls and production may go on without a stop. The comers within the mill slow down the flow of mass and will not begin to revolve with the cmshing element. The comers gather the material, wherefrom the mass is easily removable by the blows of compressed air.

[0005] One embodiment of the invention is characterized in that, at an end of the nozzle, there are one or more outward-flaring nozzle holes.

[0006] Another embodiment of the invention is characterized in that the blows of compressed air are controllable by means of piping in such a way that intervals between the blows are adjustable as desired. By means of the invention, the interior of the mill may be kept clean during production and while the mill is rotating.

[0007] The invention will be described below by way of an example with reference to the accompanying drawings, in which

[0008] Fig. 1 illustrates a mill with prior art technology,

[0009] Fig. 2 illustrates a cover structure of the mill according to the invention,

[0010] Fig. 3 illustrates a lower part of the mill in an opened state, and

[0011] Fig. 4 illustrates a structure of a compressed air nozzle as a sectional view.

[0012] The mill is designed for crushing steel slag or combustion ash in such a way that metals and slag materials can be separated. The mill is formed of a casing 1, a cover 2 and a base 3 and within the mill there is a crushing element (Fig. 1) by means of which the steel slag and combustion ash is breakable. The material is feedable to the centre of a rotor wherefrom, due to centrifugal force, it becomes ejected onto walls of the casing 1 of the mill, wherefrom it drops out via outlet apertures provided in the base 3. The mill is, in cross section, octagonal shaped and, at comers of the cover 2 of the mill, there are compressed air nozzles 4 extending through the cover, via which nozzles blows of compressed air are directable onto the comers within the mill and remove difficult, moist material that has adhered to the walls during production and while the mill is rotating. At an end of the nozzle 4, there are one or more outward-flaring nozzle holes 5. The blows of compressed air are controllable by means of piping in such a way that intervals between the blows are adjustable as desired. An octagonal shape of the mill suitably stops the vortex generated by the rotors in the material.

Claims

Claims1. A mill designed for crushing steel slag or combustion ash in such a way that metals and slag materials can be separated, and which mill is formed of a casing (1), a cover (2) and a base (3) and within the mill there is a crushing element by means of which the steel slag and combustion ash is breakable and that the material is feedable to the centre of a rotor wherefrom, due to centrifugal force, it becomes ejected onto walls of the casing (1) of the mill, wherefrom it drops out via outlet apertures provided in the base (3), characterized in that the mill is, in cross section, polygon-shaped and that, at comers of the cover (2) of the mill, there are compressed air nozzles (4) extending through the cover, via which nozzles blows of compressed air are directable onto the comers within the mill and remove difficult, moist material that has adhered to the walls during production and while the mill is rotating.

2. The mill according to claim 1, characterized in that, at an end of the nozzle (4), there are one or more outward-flaring nozzle holes (5).

3. The mill according to claim 1 or 2, characterized in that the blows of compressed air are controllable by means of piping in such a way that intervals between the blows are adjustable as desired.

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