WO2001021315A1

WO2001021315A1 - Method and installation for comminuting particles of material

Info

Publication number: WO2001021315A1
Application number: PCT/NL2000/000655
Authority: WO
Inventors: Eugeni Fedorov
Original assignee: SKEET ABA HOLDING BV
Current assignee: SKEET ABA HOLDING BV
Priority date: 1999-09-17
Filing date: 2000-09-15
Publication date: 2001-03-29
Anticipated expiration: 2002-03-17
Also published as: AU7561800A; NL1013085C2

Abstract

For comminuting particles of material a compact column of material is moved through a channel formed by openings (2) adjoining one another. Each opening is made in a disc-shaped element (1), which disc-shaped elements are placed on top of one another or one above the other with a small distance between them. At least a number of the disc-shaped elements are rotated, at least one of each set of disc-shaped elements placed above one another or on top of one another being brought into rotation. The relative positions of the delimiting walls of adjoining openings (2) change during the rotation. To increase the comminution yield the main directions of the delimiting walls of the opening (2) in each disc-shaped element (1) form an essentially equilateral triangle. On rotation of the rotary discs the direction in which the material moves is changed and the material is comminuted exclusively by the material particles pressing onto one another.

Description

Method and installation for comminuting particles of material

The invention relates in the first instance to a method for comminuting particles of material comprising: moving a compact column of material from top to bottom through a channel formed by openings adjoining one another, each made in a disc-shaped element, which disc-shaped elements are placed on top of one another or one above the other with a small distance between them, and rotating at least a number of the disc-shaped elements, at least one of each set of disc-shaped elements placed above one another or on top of one another being brought into rotation, the relative positions of the delimiting walls of adjoining openings changing during the rotation.

A method of this type is described in WO 82/03200.

Materials have to be comminuted in many sectors of industry. Examples are: pulverisation of glass waste to produce a powder, crushing and grinding minerals in mining, crushing and grinding metallurgical slags, grinding timber waste, grinding agricultural products such as wheat, crushing and grinding waste construction materials, shredding old car tyres and shredding domestic waste.

A wide variety of processes and equipment for crushing and grinding materials are known, such as jaw crushers, ball crushers, hammer mills, pendulum mills, rod mills and ball mills. All these known methods and all this known equipment display/displays the disadvantage of a high energy consumption and a low yield.

In the case of the method described in said WO 82/03200 the opening in each discshaped element is in the shape of an Archimedes spiral, that is to say a curve which has a radius which gradually decreases from a maximum value until it meets a ridge surface that joins the point of smallest radius to the point of maximum radius. The ridge surfaces of successive disc-shaped elements face in opposing directions. The size of the surface area of the openings decreases from top to bottom. Successive disc-shaped elements rotate in opposing directions. The comminution of the material to be pulverised is based mainly on shearing (cutting and scissors action). The comminution yield still leaves something to be desired.

The aim of the invention is to increase the yield of the pulverisation.

To this end the method specified in the preamble is characterised in that the main directions of the delimiting walls of the opening in each disc-shaped element form an essentially equilateral triangle and in that on rotation of the rotary discs the direction in which the material moves is changed and during this operation the material is comminuted exclusively by the material particles pressing onto one another.

It is important that on rotating the disc-shaped element through 360° the material is compressed in alternating directions as a consequence of the abovementioned equilateral triangular shape of the main direction of the delimiting walls of the openings, the material particles being moved over one another and consequently pulverised. Comminution of the material thus does not take place by means of cutting or shearing. Successive disc-shaped elements can be rotated at different speeds of rotation, in different directions of rotation, with different eccentricity of the openings with respect to the axes of rotation of the disc-shaped elements and with different relative positions of the axes of rotation of the disc-shaped elements.

In practice, as a consequence of inertia the particles of material are moved towards the periphery of the opening in a disc-shaped element and on entering the opening in a following disc-shaped element are moved towards the centre of that disc-shaped element, etc.

A multiplicity of possibilities exist for rotating the elements. One possibility is that the periphery of each disc-shaped element is circular and the disc-shaped elements are rotated in that driven rollers or gears engage or mesh on the side face of each element. Another possibility is that the disc-shaped elements are rotated by electromagnetic action. The invention also relates to an installation for carrying out the method described above. Said installation comprises a number of disc-shaped elements positioned on top of one another or one above the other a small distance apart, having an opening in each disc, a channel formed by adjoining openings and means for rotating at least one of each pair of discshaped elements located above one another, the relative positions of the delimiting walls of adjoining openings changing during rotation of the rotary disc-shaped elements. According to the invention the main directions of the delimiting walls of the opening in each disc-shaped element form an essentially equilateral triangle.

The width of the walls of the openings in the disc-shaped elements is chosen such that an opening in a disc-shaped element located above is overlapped by a disc-shaped element located beneath it, for each rotational position with respect to said disc-shaped element located directly beneath it.

The invention will now be explained in more detail with reference to the figures.

Fig. 1 shows an axial section of an illustrative embodiment of a destruction installation according to the invention.

Fig. 2 shows a plan view of the installation according to Fig. 1 on a somewhat larger scale.

Fig. 3 shows a perspective view of part of the destruction installation according to Figs 1 and 2 in an exploded view.

Fig. 4 shows a plan view of an alternative embodiment of the destruction installation according to the invention where other drive means are used.

Fig. 5 shows a section along the line V - V in Fig. 4.

Fig. 6 shows a plan view of a disc-shaped element with openings, the shape of which differs compared with that according to the preceding figures.

The destruction installation according to Figs 1 - 3 comprises a number (6 in the case shown) of disc-shaped elements 1 positioned above one another and mounted such that they are rotatable. A very small space is maintained between these disc-shaped elements, for example with the aid of a number of ball bearings positioned close to the rim of the disc- shaped elements. However, other solutions are also conceivable. An equilateral triangular opening 2 has been hollowed out in each disc, preferably eccentrically with respect to the axis of rotation of the disc-shaped element concerned. A housing 3 is positioned around the discshaped elements 1 and between the housing 3 and the disc-shaped elements 1 there are means for rotating the disc-shaped elements. In the embodiment according to Figs 1 - 3 these means are electromagnetic in nature, coils 5 having been fitted in the inner lining 4 of the housing 3 and magnets 6 having been accommodated in the disc-shaped elements 1. The coils are fed with a direct or alternating current during operation. A gap 7 is left between the lining 4 of the housing 3 and the disc-shaped elements 1.

The mode of operation is as follows: The particles of material to be comminuted are fed via a feed tube 8 into the top of the housing 3. The discs 1 are rotated by the drive means such that the speeds of rotation of successive disc-shaped elements differ and or the directions of rotation of successive discs differ. Furthermore, the eccentricity of the openings in the disc-shaped elements with respect to the axes of rotation of said elements can differ and the relative positions of the axes of rotation of the various disc-shaped elements can differ.

Successive equilateral triangular openings 2 form a continuous channel in which a compact column of particles of material is present. The geometric shape of the channel changes at the transition from the opening 2 in the one disc-shaped element 1 to the opening 2 in the next disc-shaped element 1. The particles are forced to move in accordance with a modified path, being pressed onto one another and scraped over one another under pressure. By this means extremely efficient comminution of the particulate material takes place with minimum energy. The openings 2 can have the same eccentricity with respect to the successive axes of rotation of the disc-shaped elements.

Fig. 3 shows the situation where successive disc-shaped elements 1 rotate in different directions of rotation. What is concerned here is that the particles in the compact column of material are forced in a different direction at the transition from the one disc-shaped element to the other disc-shaped element. The angles at which the inner faces of the triangular openings 2 engage on the particulate material will be changed at the transition from the one disc-shaped element to the next disc-shaped element.

The shape of the openings 2 does not have to be in an equilateral triangle, provided that the main directions of the delimiting walls of the opening 2 in a disc-shaped element 1 form an essentially equilateral triangle. Fig. 6 shows such an embodiment.

If the comminuted material is smaller than the distance between the disc-shaped elements 1 , a very small amount of this material is able to escape via the gaps between said disc-shaped elements and, moreover, to drop down via the circular gap 7. Comminuted material can be discharged via the discharge 9 and - if necessary - recirculated. In the embodiment according to Figs 4 and 5 each of the disc-shaped elements 1 is joined by pins 10 to an outer ring 11 which is provided with teeth 12 over its entire periphery. Only some of these teeth have been drawn. Three driven gears 14 engage in the teeth 12. There is a circular gap 13 between the outer ring 11 and each of the discs 1. This has the same function as the gap 7 in the embodiment according to Figs 1 - 3.

Claims

1. Method for comminuting particles of material comprising: moving a compact column of material from top to bottom through a channel formed by openings (2) adjoining one another, each made in a disc-shaped element (1), which disc-shaped elements are placed on top of one another or one above the other with a small distance between them, and rotating at least a number of the disc-shaped elements, at least one of each set of disc-shaped elements placed above one another or on top of one another being brought into rotation, the relative positions of the delimiting walls of adjoining openings changing during the rotation, characterised in that the main directions of the delimiting walls of the opening (2) in each disc-shaped element (1) form an essentially equilateral triangle and in that on rotation of the rotary discs (1) the direction in which the material moves is changed and during this operation the material is comminuted exclusively by the material particles pressing onto one another.

2. Method according to Claim 1, characterised in that the periphery of each disc-shaped element (1) is circular and the disc-shaped elements are rotated in that driven rollers or gears (14) engage or mesh on the side face of each disc-shaped element.

3. Method according to Claim 1, characterised in that the disc-shaped elements (1) are rotated by electromagnetic action (5, 6).

4. Installation for carrying out the method according to Claim 1, comprising: a number of disc-shaped elements (1) positioned on top of one another or one above the other a small distance apart, having an opening (2) in each disc, a channel formed by adjoining openings (2) and means for rotating at least one of each pair of disc-shaped elements (1) located above one another, the relative positions of the delimiting walls of adjoining openings changing during rotation of the rotary discs, characterised in that the main directions of the delimiting walls of the opening (2) in each disc-shaped element (1) form an essentially equilateral triangle.

5. Installation according to Claim 4, characterised in that the width of the walls of the openings (2) in the disc-shaped elements (1) is chosen such that an opening in a disc- shaped element located above is overlapped by a disc-shaped element located beneath it for each rotational position with respect to said disc-shaped element located directly beneath it.