WO1996032195A1

WO1996032195A1 - Rotor blade construction for impact crusher

Info

Publication number: WO1996032195A1
Application number: PCT/NL1996/000152
Authority: WO
Inventors: Johannes Petrus Andreas Josephus Van Der Zanden
Original assignee: IHC Holland NV
Current assignee: IHC Holland NV
Priority date: 1995-04-11
Filing date: 1996-04-10
Publication date: 1996-10-17
Anticipated expiration: 1997-10-11
Also published as: NL1000117C2; AU5163396A

Abstract

A rotor blade construction for an impact crusher, in which the rotor blade (1) is provided with guides (3), on which guides a casing (2) in the form of a downward widening truncated cone is placed, on which casing guides (4) are disposed, which guides run from the top edge (7) of the casing to the bottom edge (8) of the casing (2), and from there run further to a point on the casing midway between the guides present there, from where the casing guides run further over the rotor blade (1) to the edge of the rotor blade.

Description

ROTOR BLADE CONSTRUCTION FOR IMPACT CRUSHER

TECHNICAL FIELD

The invention relates to a rotor blade construction for an impact crusher, having a dish-shaped rotor blade which is mounted in such a way that it is rotatable about a vertical axis, and which is provided with shorter or longer guides which are straight, curved or bent and have a smooth steel guide face, or which are in the form of a chamber vane in which granular material settles under the influence of centrifugal force when the rotor blade is turning, which granular material as such forms a natural guide face there, which guides run from the centre part in a radial or non-radial direction towards the edge of the rotor blade, and by means of which rotor blade construction granular material which is placed in the centre of the rotating rotor blade, under the influence of centrifugal force, is brought to velocity along, or by a blow from, the guides and is flung outwards over the edge of the rotor blade; in particular rotor blade constructions for impact crushers in which the stony granular material is flung by means of a rotor blade against a wall disposed around the rotor blade, which granular material thereby breaks through the force of the impact.

BACKGROUND ART Such rotor blades are used on a large scale in impact crushers and are known from a large number of patent specifications. A distinction can be made here between rotor blades with radially outward directed guides which are known, inter alia, from US Patent Specifications 5,174,513, 3,955,767 - 2,898,053 - 2,357,843 and Canadian Patent Specification 521 ,071. The guides are not designed symmetrically here, which is why the rotor blade works in one direction of rotation. The rotor blades which are known from British Patent Specification 394,478 and French Patent Specification 902,258 have a symmetrically designed and radially disposed guide construction, so that the rotor blade can be used rotating both clockwise and anticlockwise. Moreover, if the guides are designed as types of equilateral triangles which are disposed with (rounded) points directed radially along the edge of the rotor blade, the rotor blade can be used rotating in both directions; such rotor blades are known from US Patent Specifications 3,578,254 - 3,652,023 - 3,767,127 - 4,126,280 - 4,166,585 - 5,323,974 and European Patent Specifications 0562 194 A2-0607 977 A2. The straight guides can also be directed in a non-radial manner; such rotor blades are known from US Patent Specifications 3,606,182 and 2,752,098, or are in the form of shorter guides which are disposed further towards the edge of the rotor blade and are known from, inter alia, US Patent Specifications 3,074,657 - 3,088,685 - 3,540,667 - 3,093,329 - 3,044,720 - 2,991 ,949 - 4,699,326. Instead of straight or triangular guides, it is also possible to use curved guides which are disposed in a fan shape and are known from, inter alia, British Patent Specifications 309,854 and 376,760 and German Patent Specification 688,169. The fan shape has only a limited influence on the ratio between the tangential and the radial velocity component and essentially leads only to additional wear, and is therefore seldom used. The guides can also be disposed further out from the centre, so that the granular material moves over a greater distance, i.e. without guide, over the rotor blade, and is received by short guides only when it is further outwards towards the edge of the rotor blade, which short guides can be made thicker because further outwards the distance, and thus the passage space, increases between the guides, so that the guides have a longer service life and need not be exchanged so often; with which guide blocks, which at a greater distance from the centre operate at a greater speed, the material is brought to velocity more with an impact, and possibly partially by means of guiding; such rotor blades are known from, inter alia, US Patent Specifications 3,032,169 - 3,000,579 - 3,258,211 - 3,058,679 - 3,873,047 - 4,090,673 - 3,474,974 - 3,058,679 - 4,326,676 - 4,784,339 - 4,090,673 - 5,184,784. Instead of a guide with a smooth guide or impact face, use can also be made of chamber vanes, in which granular material settles under the influence of centrifugal force, thus producing a natural guide face, with the result that the wear is greatly reduced; such rotor blades, which in most cases are in the form of a drum construction, or rotor housing, having in the side walls openings through which the material is flung outwards, are known from, inter alia, US Patent Specifications 3,334,823 - 3,148,840 - 3,174,697 - 3,860,184 - 4,659,026 - 4,560,113 - 4,579,290 - 4,796,822 - 4,896,838 - 4,586,663 - 5,131 ,601 and European Patent Specifications 0166 674 A2 - 0101 277 A3 - 0261 913 A3 - 0187 252 A2 - 0265 580 Bl . In this case the granular material can be guided in succession over several vanes disposed on the rotor blade; such a rotor construction is known from French Patent Specification 1,355,213.

Patent Specification PCT WO 89/04720 discloses a rotor blade construction with fans projecting along the edge of the rotor blade, by means of which the number of guides can be increased to six. US Patent Specification 4,923,131 discloses a rotor blade construction which is designed as a sort of truncated triangle with three outlets. US Patent Specifications 4,690,341 - 3,970,257 disclose rotor blade constructions with chamber vanes having only two outlets. Fewer guides are used if a great impact velocity is required, while the capacity must remain limited. Instead of a guide vane, the rotor blade can also be equipped with pins between which material settles. Such a construction is known from US Patent Specification 4,390,136, in which the pins are disposed symmetrically along the edge, so that the rotor blade can be used rotating both clockwise and anticlockwise. US Patent Specification 1,499,455 discloses a rotor blade which can be used rotating both clockwise and anticlockwise, and in which the guides are formed bv three circle segments which are disposed along the edge of the rotor blade construction. German Patent Specification 1,253,562 and British Patent Specification 1,013,610 disclose rotor blades which are designed with two rotor blades disposed above one another and fed centrally by means of a conical centre part. German Patent Specification 1,814,751 discloses a rotor blade construction which is fed centrally in the middle and has four rotor blades disposed above one another. Patent Specification PCT WO 91 /11260 discloses an impact crusher with two or more rotor blades placed above one another and fed centrally from the middle, which is possible because the guides are placed vertically and axially staggered, while the material is distributed over the various rotor blades and guided outwards. US Patent Specifications 1,656,756 - 1,636,033 - 1,911,193 disclose rotor blade constructions in which a number of rotor blades are disposed below one another and are driven by the same shaft, in the case of which the material is flung from the first rotor blade against an impact ring disposed aiound the rotor blade, following which the granular material, and any broken-off fragments resulting therefrom, fall onto the following rotor blade situated lower down, and are thus flung again against an impact ring disposed around this rotor blade; a process which can be repeated several times. In this case the rotor blades can be of increasing diameter in the downward direction. British Patent Specification 367,760 discloses a rotor blade construction where two rotor blades are placed above one another, and where the top rotor blade is fed over a cone-shaped centre part and the bottom rotor blade is fed by the shaft. A number of the rotor blades are convex or even conical in the centre, with the result that a better distribution of the granular material from the centre of the rotor blade to the guides is achieved; such rotor blades are known from US Patent Specifications 4,065,063 and 2,798,674, and from German Patent Specification 591 ,968. Finally, US Patent Specification 1 ,293,655 discloses a rotor blade construction which is fully conical and is provided with radially directed guides.

In the case of the known impact crushers the granular material is placed on the centre part of the rotating rotor blade and from there is distributed over the guides, and is brought to velocity along the guides, following which the granular material is flung away over the edge of the rotor blade. In the case of all known impact crushers described here the rotor blades are provided with guides which are disposed horizontally in one plane on the rotor blade, which guides have their starting point at some distance from the centre of the rotor blade, and from there run horizontally over the rotor blade to the outside edge of the rotor blade. The number of guides which can be disposed on the rotor blade is consequently limited. The centre part of a rotor blade onto which the granular material is metered forms a free circular space lying centrally within the starting points of the guides, and from which the granular material is distributed over the guides. In this case the free horizontal passage space for the granular material along the edge of the centre part, between the starting points of the guides, must be such that the granule movement, or the distribution of the granular material from the centre part over the guides, is not impeded. Assuming a certain required free passage space along the guides, which is determined by the diameter of the granular material, the number of guides which can be situated in one plane on the rotor blade is determined by the circumference of the centre part; in this case the radius of the centre part cannot be made too large, because the tangential speed from the centre towards the edge of the rotor blade increases exponentially, and the granular material further towards the outside is received by the guides at such velocity that this can be described as an impact, in which case the only advisable solution is to fit guide blocks. With such guide blocks the material is brought to velocity with an impact and is flung over the edge of the rotor blade, in which case both the take-off velocity and the take-off angle of the granules can vary widely. The length of the guides is likewise subject to a maximum, because further towards the outside the space between the guides increases exponentially, while said space cannot be utilized. In the design of a rotor blade a choice therefore always has to be made between guide contact and impact contact of the guides with the granular material, and an optimum has to be sought between the necessary free passage segment between the starting points of the guides, the number of guides disposed on the rotor blade, the size or the diameter of the free space in the centre of the rotor blade, the diameter of the rotor blade, the length of the guides, the angular speed of the rotor blade and, of course, the required take-off velocity and take-off angle of the granular material. The possibilities are limited here, which in practice means that the rotor blades of the known impact crushers for coarser granular material (10 to 50 mm) are designed with a maximum of five (one construction with six outlets is known), and in the majority of cases with only three or four, guides or guide blocks. However, if more material is being conveyed over the rotor blade, with the diameter and angular speed otherwise remaining the same, the energy consumption increases only to a limited extent. There is therefore a question of a geometrical problem, where the free passage space between the starting points of the guides is the determining factor for the number of guides which can be fitted on the rotor blade; and the possibilities are consequently limited.

DISCLOSURE OF INVENTION

The object of the invention is a rotor blade construction which makes it possible to increase the number of guides on the rotor blade, essentially to double the number, without increasing the diameter of the rotor blade, and without the granule movement being additionally impeded, or with the free passage space for the granular material between the starting points of and along the guides remaining the same, as a result of which the capacity of the rotor blade, and therefore the capacity of the impact crusher, is increased considerably while maintaining the same angular speed of the rotor blade.

To this end, the invention provides for a casing in the form of a truncated cone to be placed in said centre on the rotor blade, which casing rotates with the rotor blade. Approximately half of the granular material is metered through the opening in the top of the truncated cone casing, onto the centre part of the rotor blade, which granular material is guided to the edge of the rotor blade, by way of the guides whose starting points are on the rotor blade in the space below the truncated cone casing, over the rotor blade and under the edge of the bottom circle of the truncated cone. The other half of the granular material is guided over the outer casing of the truncated cone to the edge of the rotor blade, by way of guides which are disposed on the outside wall of the truncated cone casing, and which run from the top edge of the truncated cone casing along the bottom edge of the truncated cone casing to the rotor blade and on over the rotor blade to the edge of the rotor blade; in this case, approximately at the position of the bottom edge of the truncated cone casing, midway between the guides whose starting point is on the rotor blade, the casing guides come into contact with the rotor blade on a circle edge whose circumference is twice the size of that of the free centre part of the rotor blade.

With such a truncated cone construction it is possible to double the number of guides, while the free passage spaces between and along the guides on the rotor blade and the cone casing is nowhere less than the passage space between the starting points of the guides on the rotor blade. Furthermore, the granular material which is guided along the inside and outside respectively of the truncated cone casing to the edge of the rotor blade covers the same horizontal distance over the rotor blade. The material which is guided through and over the truncated cone casing to the edge of the rotor blade consequently in both cases develops approximately the same radial velocity, so that the granular material as a whole leaves the rotor blade along the various guides at approximately the same vector velocity and take-off angle.

What is achieved with such a rotor blade construction is that the capacity of the rotor blade, and thus the capacity of the impact crusher, is virtually doubled, without the granular material on the rotor blade being additionally impeded, and with otherwise the same diameter and angular speed of the rotor blade, and the granular material leaves the rotor blade along the various guides at approximately the same vector velocity and take-off angle, while the quantity of energy required for driving the rotor blade increases only to a limited extent. For the best possible regulation of the granule movement over the cone casing, the invention makes it possible for the casing, which is in the form of a truncated cone, to be curved or bent, rather than straight, in the vertical radial plane. To this end, the invention also provides the possibility for the guides on the outside wall of the truncated cone casing to be slanting or curved, so that material is prevented from passing over the bottom edge of the cone, between the guides, onto the rotor blade.

The invention also provides the possibility for the guides on the rotor blade and the cone casing to be symmetrical and to be placed radially, so that the rotor blade can be used rotating both clockwise and anticlockwise.

The invention also provides the possibility for a cover plate to be placed over the truncated cone casing, which cover plate rotates along with the rotor blade and runs through to the edge of the rotor blade, with the result that a sort of drum construction or rotor housing is produced, having in the side walls openings through which the material is flung outwards.

BRIEF DESCRIPTION OF DRAWINGS

The invention is explained in greater detail below with reference to the following drawings.

Figure 1. Three-dimensional diagrammatic drawing of the rotor blade construction. Figure 2. Three-dimensional diagrammatic drawing of the rotor blade construction having in the centre a casing with a straight outside wall. Figure 3. Three-dimensional diagrammatic drawing of the rotor blade construction having in the centre a casing with a curved outside wall.

Figure 4. Diagrammatic cross-section of the rotor blade construction with casing with a curved outside wall. Figure 5. Diagrammatic cross-section of the rotor blade construction with a casing with a curved outside wall. Figure 6. Diagrammatic top view of the rotor blade construction with radially positioned guides. Figure 7. Diagrammatic top view of the rotor blade construction with guides which are not directed radially on the outside wall of the casing. Figure 8. Diagrammatic cross-section of the rotor blade construction with central cover plate over the casing part of the rotor blade.

Figure 9. Cross-section of the rotor blade construction with cover plate over the entire rotor blade and side walls, so that this is effectively a rotor housing.

DETAILED DESCRIPTION Figure 1 shows a three-dimensional diagrammatic illustration of the rotor blade construction, in which guides (3) are disposed on the rotor blade (1), which guides have their starting points on the rotor blade (1 ) and run over the rotor blade (1) to the edge (10) of the rotor blade (1 ). Placed on the guides (3) is a casing (2) which is in the form of a truncated cone, the wall (9) of the casing being curved inwards. The granular material is guided from the top into the opening (13) in the top circle (7) of the casing (2), where it is received in the free centre part (5) of the rotor blade (1) between the rotor blade guides (3). From there, under the influence of centrifugal force, the granular material is distributed over the rotor blade guides (3), in which case the passage space (6) between the starting points of the rotor blade guides (3) must be such that the granular material can move freely through between them. The granular material is then guided along the rotor blade guides (3) over the rotor blade (1) under the bottom edge (8) of the casing (2) to the outside edge (10) of the rotor blade (1) and flung outwards over the edge (10) of the rotor blade (1).

The granular material can also be guided along the outside wall (9) of the casing (2) to the outside edge (10) of the rotor blade (1 ), in which case the granular material on the outside wall (9) of the casing (2) is received by the casing guides (4) which have their starting point along the top edge (7) of the casing (2) and which run over the outside wall (9) of the casing (2) to the bottom edge (8) of the casing (2) and, vertically below it, touch the rotor blade (1) at a point on the rotor blade (1) situated between the adjacent rotor blade guides (3), from which point the rotor blade guides (3) run further over the rotor blade (1 ) to the edge (10) of the rotor blade (1 ).

The circumference of the free circle space (5) in the centre of the rotor blade (1) between the starting points of the rotor blade guides (3) is approximately the same as that of the top circle (7) of the casing (2); which circle circumference is the determining factor for the number ot rotor blade guides (3) which can be situated along the edge (6) of the free circle space (5).

The circumference of the circle space (11 ) along the points where the casing guides (4) which have their starting point along the top edge (7) of the casing (2) touch the rotor blade (1 ) must be at least twice the circumference of the free centre circle (5) on the rotor blade (1 ) between the starting points of the rotor blade guides (3). This ensures that the free passage space (6) on the rotor blade (1 ) is the same along both circle spaces (5; 11), so that the granular material is not impeded anywhere on the rotor blade (1) in its free passage or movement along the guide strips (3; 4), and thus nowhere on the rotor blade (1) between the guides encounters a passage space which is smaller than the passage space (6) between the starting points of the guides (3) centrally (5) on the rotor blade (1 ).

Figure 2 and Figure 3 show the rotor blade construction designed respectively with a casing (15) with an outside wall which is straight from top to bottom and a casing (2) with an outside wall which is curved from top to bottom.

Figure 4 and Figure 5 give cross-sections, and Figure 6 a top view of the rotor blade construction in which no cover plate is placed on the guides (3; 4). Figure 7 gives a top view of the rotor blade construction in which the guides (17) have their starting point along the top edge (7) of the rotor blade (1), and in which the guides (17) along the part of the guides (17) running over the outside wall (9) of the casing (2) are not radially directed, with the result that the granular material is received better by the guides (17) and guided to the rotor blade (1).

Figure 8 gives a cross-section of the rotor blade construction in which the adjacent guides (4) along the casing part are provided with a cover plate (12), with the result that guide channels are produced.

Figure 9 gives a cross-section of the rotor blade construction which in this case is in the form of a rotor housing, a cover plate (18) which covers the entire rotor blade (1) being placed on the guides (3; 4), while the part of the guides (21) situated below the casing (2) is continued on up until it is against the inside wall of the casing (2), so that all guides (4; 21) are now in the form of guide channels, and along the outside edge (10) of the rotor blade (1 ) a wall (20) which connects the cover plate (18) and the rotor blade (1) to each other is disposed, in which wall (20) openings (19) are provided along the guides (4; 21 ), through which the material is flung out unimpeded over the edge (10) of the rotor blade (1 ).

Claims

1. Rotor blade construction for impact crusher, having a dish-shaped rotor blade which is mounted in such a way that it is rotatable about a vertical shaft, and which is provided with shorter or longer guides which are straight, curved or bent and have a smooth steel guide face, or which are in the form of a chamber vane in which granular material can settle under the influence of centrifugal force when the rotor blade is turning, which granular material as such forms a natural guide face there, which guides run from the central part in a radial or non-radial direction towards the edge of the rotor blade, and by means of which rotor blade construction material for crushing which is placed in the centre of the rotating rotor blade, under the influence of centrifugal force, is brought to velocity along, or by a blow from, the guide and is flung outwards over the edge of the rotor blade; in particular rotor blade constructions for impact crushers in which stony granular material is flung by means of such rotor blades against a wall disposed around the rotor blade and breaks in the course of this through the force of the impact, characterized in that in the centre of the rotor blade (1), which is provided with guides (3), a casing (2), which is in the form of a sort of truncated cone whose outside wall (9; 15) is made straight or bent, and which rotates along with the rotor blade (1), is placed on said guides (3), and along the outside wall (9) is provided with guides (4), while the casing guides (4) run over the outside (9) of the casing (2), from the top edge (7) to the bottom edge (8) of the casing (2), and from there run further to the rotor blade (1 ) and over the rotor blade (1 ) to the outside edge (10) of the rotor blade (1).

2. Rotor blade construction for impact crusher, according to Claim 1 , characterized in that the casing (2), which is in the form of a truncated cone, is not disposed on the guides (3), but in the centre above the rotor blade (1).

3. Rotor blade construction for impact crusher, according to Claims 1 and 2, characterized in that the guides (4) which are disposed on the outside wall (9) of the casing (2), which is in the form of a truncated cone, touch the rotor blade (1) at the bottom along the bottom edge (8) of the casing (2) at points midway between two adjacent guides (3) which have their starting points on the rotor blade (1 ).

4. Rotor blade construction for impact crusher, according to Claims 1 to 3, characterized in that the number of guides (4) along the outside wall (9) of the casing (2), which is in the form of a truncated cone, corresponds to the number of guides (3) which have their starting points on the rotor blade (1).

5. Rotor blade construction for impact crusher, according to Claims 1 to 4, characterized in that the outside wall (9) of the casing (2), which is in the form of a truncated cone, is a curved or bent shape in the vertical plane.

6. Rotor blade construction for impact crusher, according to Claims 1 to 5, characterized in that the casing (2), which is in the form of a truncated cone, in the top circle (7) has an opening (13) with a diameter which is approximately the same as that of the free space (5) in the centre of the rotor blade (1) between the starting points of the guides (3) on the rotor blade (1), and a bottom circle (8) which has a circumference which is at least twice the size of that of the free circle space (5) in the centre of the rotor blade (1) between the guides (3) which have their starting points on the rotor blade (1).

7. Rotor blade construction for impact crusher, according to Claims 1 to 6, characterized in that the guides (4) of the casing (2), which is in the form of a truncated cone, touch the rotor blade (1) on a line (11) of a circle whose circumference is at least twice the size of that of the free circle space (5) in the centre of the rotor blade (1) between the starting points of the guides (3) of the rotor blade (1).

8. Rotor blade construction for impact crusher, according to Claims 1 to 7, characterized in that in the guides (21) whose starting points are on the rotor blade (1), the part situated below the casing (2), which is in the form of a truncated cone, is continued until it is against the inside wall of the casing (2).

9. Rotor blade construction for impact crusher, according to Claims 1 to 8, characterized in that a covering plate (12) which rotates along with the rotor blade (1) is placed on the guides (4) of the casing (2), which is in the form of a truncated cone.

10. Rotor blade construction for impact crusher, according to Claims 1 to 9, characterized in that a covering plate (18) which runs up to the edge (10) of the rotor blade (1 ) is placed on guides (4) of the casing (2), which is in the form of a truncated cone.

11. Rotor blade construction for impact crusher, according to Claims 1 to 10, characterized in that a vertical circular wall (19) is placed along the edge (10) on the rotor blade (1), which wall connects the rotor blade (1) and the covering plate (18) to each other, while there are openings (20) in said wall through which the granular material is flung outwards from the rotor blade (1 ), and which do not impede the gran¬ ule movement on the rotor blade (1).

12. Rotor blade construction for impact crusher, according to Claims 1 to 11, characterized in that the guides (4) on the outside wall (9) of the casing (2), which is in the form of a truncated cone, and the guides (3) on the rotor blade (1 ) are all disposed in a radially directed manner and are made symmetrical, so that the rotor blade (1) can function rotating both clockwise and anticlockwise.

13. Rotor blade construction for impact crusher, according to Claims 1 to 12, characterized in that the guides (17) on the outside wall (9) of the casing (2), which is in the form of a truncated cone, are made slanting or curved, instead of being directed radially and straight.

14. Rotor blade construction for impact crusher, according to Claims 1 to 13, characterized in that in the guides (3; 4) on the rotor blade (1) the part which lies in the vertical plane outside the bottom edge (8) of the casing (2), which is in the form of a truncated cone, is in the form of chamber vanes.