WO2008105697A1

WO2008105697A1 - Chute liner element, chute lining, use thereof, and a method for fastening a chute liner element

Info

Publication number: WO2008105697A1
Application number: PCT/SE2007/000203
Authority: WO
Inventors: Andreas Hoffmann; Peter Lundberg
Original assignee: Metso Minerals (Wear Protection) Ab
Priority date: 2007-03-01
Filing date: 2007-03-01
Publication date: 2008-09-04
Also published as: AU2007347914B2; AU2007347914A1

Abstract

A resilient chute lining element (100) has a first end (106) and a second end (108), a top face (110) and bottom face (112) . The first end (106) is adapted to be removably fixed to a chute surface (102, 104) and said second end (108) extends away from said chute surface (102, 104) and is adapted to move freely in at least one direction. The first end (106) comprises first snap- locking means (114) adapted to matingly engage second snap-locking means (116) arranged on said chute surface (102, 104) .

Description

CHUTE LINER ELEMENT, CHUTE LINING, USE THEREOF, AND A METHOD FOR FASTENING A CHUTE LINER ELEMENT

Technical Field of the Invention

The present invention relates to a chute liner element, a chute lining comprising several chute liner ele- ments, the use thereof, and a method for fastening a chute liner to a chute liner wall.

Background Art

In the mining industry chutes are often used to lead material from one processing step to another, e.g., from one conveyor to another, from a transportation vehicle to a conveyor belt or vice versa. The ore is prone to adhere to the walls of the chute, especially if the ore is moist. This results in accumulation of ore on the chute walls, which accumulation interferes with passage of ore through, or over, the chute.

In order to avoid said problems prior art suggests the use of resilient members, forming a lining on the chute walls. The resilient members are attached to the wall with one end, while the other end projects out from the wall. Ore will adhere to the resilient members, but the accumulation will be interrupted when a larger ore particle hits the resilient member on which ore has accumulated. The resulting vibration of the resilient member will eliminate the accumulation. A prior art solution is disclosed in WO-03/086907. In said document it is also emphasized that the resilient members operatively work as a wear-resistant liner, since they will constitute the area exposed to the ore that is transported through the chute. As the resilient members are worn out, they can be replaced by others . In the above prior art the resilient members are attached to the chute wall by means of a screw/nut arrangement. Common for the prior art solutions is that they are cumbersome to mount to the chute wall, which increases the downtime of a facility during maintenance/repair.

Summary of the Invention

The present invention aims at alleviating the above drawbacks by the provision of a resilient chute liner element, a chute comprising such element, the use of a chute liner element for a chute, and a method for fasten- ing a chute liner to a chute liner wall, in accordance with the corresponding independent claims. Preferred embodiments of the invention are disclosed in the sub- claims .

An inventive resilient chute liner element in accor- dance with claim 1 provides an element that can be mounted to a chute or exchanged in a simple and efficient manner, without the need of additional fastening devices or several tools. In this way the downtime related to a change of liner elements is reduced, and thereby the costs too.

In one or more embodiments the element may comprise an abutment surface arranged on an inner surface facing towards the chute surface (i.e. away from the second end) , said abutment surface being adapted to operatively abut the chute surface. The abutment surface prevents the lining element from rotating out of position once it has been arranged on the chute surface. This is particularly- useful when the second end of the lining element is subjected to large amounts of falling material. In one or more embodiments the resilient chute liner element may form an integral unit. This feature implies that the advantages presented above do not only relate to the mounting of the element, but to the production of said element too. By forming the element in a single mould/extruder the production of the element will be cost-efficient too, that is the production will not be more complex than before and the result will include yet another element (the first-snap locking means) .

In one or more embodiments the first snap-locking means may comprise an elongate recess, which is easily formed with the above production methods. The elongate recess preferably extends parallel with the chute liner wall .

In one embodiment the recess may be arranged on a side facing away from the abutment surface and in another embodiment it may be arranged on a bottom face of the first end. The former solution requires slightly less material, yet both are beneficial from a production and use standpoint. Having the elongate recess in the lower side, or along the side facing away form the backing plate, is a convenient way of obtaining suitable load bearing characteristics. In use the snap-locking means will mainly experience two forces, one of which is directed downwardly. The inventive way of attaching the lining element to a chute wall handles this force in an efficient man- ner. The other force is a force that tries to rotate the lining element off the second snap-locking means. In order to handle this force in an expedient fashion the first end has an abutment as described above

The lining element is preferably made of a material comprising rubber or polyurethane with a hardness below 80° Shore A, preferably below 60° Shore A and more preferably around 40° Shore A. Said materials are well used within the field of the invention and have been proven suitable for the purpose. The applicant of the present invention is not aware of materials with a hardness in the softer range (around 40° Shore A) being used for the inventive purposes . A rule of thumb is that the softer the rubber/PU the larger the abrasive strength, which makes softer materials preferable as far as abrasive strength is concerned. A drawback with softer materials is that they tend to absorb too much of an impact locally, thus preventing vibration to spread along the width (parallel to the chute wall) of the lining element. If the element comprises PU it may be produced using injection moulding or by using an open mould. If the element comprises rubber it may be produced using compres- sion moulding, injection moulding and extrusion.

To increase the likelihood that material build-up is vibrated off the lining element when it is hit by particulates having a certain inertia the lining element may be armoured with armour elements extending at least in a direction parallel to the chute wall. The armouring elements distribute a locally induced vibration along the entire width of the lining element. The use of armour elements, in the form of elongate rods or bars with optional cross sections, makes it possible to optimize the choice of material for the lining element regarding abrasive strength and still obtain suitable characteristics when it comes to the distribution of vibrations from an impact .

The armour element may comprise a material chosen from the group consisting of glass fibre, which is destructible, non-rusting, and fatigue resistant; polyam- ide, which has the same advantages as glass fibre and enables the amount of rubber/PU to be reduced; and rubber, PU or PC. In this field, as in many other fields, the cost for getting rid of waste material is increasing. Using an armouring material from the same group, in terms of disposal, as the rest of the lining elements, makes the procedure less costly. Compare, e.g., a situation where the armouring elements are made of metal, which has to be separated from the rest of the lining element prior to disposal, and a situation where the armouring elements are made of a harder PU or PC, which can be destructed together with the rest of the lining element.

In one embodiment the armour elements have a length axis extending in a direction forming an angle α>0 relative to the chute wall. This feature makes it possible to control the way a lining element flexes, and thus control a flow of material through the chute. For the same purpose a cross section of an individual armour element may vary along its length.

In a situation where a lining element is exposed to excessive wear, a wear portion can be arranged on a specific area of the lining element; on the top face or around the tip of the second end. The wear portion can be made of ceramic, such as alumina, silicon oxide, zirconium or other material such as steel, PU, polyamide or other low-friction material.

An inventive chute liner is a liner comprising at least one resilient chute liner element. The lining element is preferably attached to the liner by a second snap-locking means in the form of an elongate ledge which is essentially horizontally attached - directly or indirectly - to the chute wall and which comprises an upwardly extending longitudinal portion which fits matingly into the recess of the lining element. For simplicity the elongate ledge preferably has an L-shaped cross section. The inventive chute liner obtains all the advantages connected to the resilient chute lining elements .

The fastening of the chute lining elements or the chute liner to a chute wall can either be direct, by fastening the second snap-locking means to the chute wall, or indirect, by fastening the second snap-locking means to a backing plate and attaching the backing plate to the chute wall. When a backing plate is used the second snap- locking device is preferably welded to the backing plate, while the backing plate is attached to the chute wall by means of screws, hooks or other removable fastening means .

Brief Description of the Drawings

Fig. 1 is a cross section of a resilient chute liner element according to a first embodiment of the present invention, mounted to a chute wall. Fig. 2 is a cross section of a resilient chute liner element according to a second embodiment of the present invention, mounted to a chute wall.

Fig. 3 is a perspective view of a chute, on the wall of which resilient chute liner elements according to a first embodiment of the present invention are mounted.

Figs 4-9 show cross sections of alternative embodiments of the present invention.

Description of Preferred Embodiments of the Invention

Fig. 1 shows a resilient chute lining element 100 according to a first embodiment of the present invention, operatively fastened to a chute wall 102, via a backing plate 104. The lining element 100 has a first end 106 and a second end 108, a top face 110 and a lower face 112. The first 106 end has, on a side facing away from the backing plate 104, an elongate recess 114, forming a first snap-locking means. The elongate recess 114 is adapted to matingly engage a projection or bead 116 on an elongate ledge 118 with an L-shaped cross section, forming a second snap-locking means. Said elongate ledge 118 is preferably welded to the backing plate 104 or chute wall 102, but could also be fastened by means of screws or brackets, to the backing plate 104 or directly to the chute wall 102. For engagement the element of Fig. 1 is simply pressed downwards until the mating snap-locks 114 and 116 engage. The lining element 100 is, if needed, given a slight thump with a hammer, forcing the snap- locking means into engagement. When the element 100 is in a mounted position, an inner side 120 of the first end

106, said inner side facing away from the second end 108, operatively abuts the backing plate 104, or when applicable, the chute wall 102. A side 122 of the first end 106 facing away from the backing plate 104 is provided with a chamfer 122 in order to simplify the arrangement of the liner element 100 on the chute wall 102. The shape of the first end 106 provides stability in the mounted position, the inner side 120 operatively abutting the chute wall 102 securing that the lining element 100 does not rotate out of position when subject to higher loads. When removing the element 100 a screw driver, crowbar or such can be used to loosen the element at one end after which the element may be removed by hand. In the following figures, describing further embodiments, reference numerals for like parts correspond to the numerals for the first embodiment increased by 100, 200, 300 etc. Fig. 2 shows a resilient chute lining element 200 according to a second embodiment of the present invention, operatively fastened to a chute wall 202, via a backing plate 204. The lining element 200 has a first end 206 and a second end 208, a top face 210 and a lower face 212. The first end 206 has an elongate recess 214, forming a first snap-locking means, extending along its lower side. The elongate recess 214 is adapted to matingly engage an elongate ledge 218 with an L-shaped cross section, and a bead 216 formed thereon, forming a second snap-locking means, welded to the backing plate. For engagement and disengagement of the first and second snap- locking means one proceeds in accordance with the description concerning the previous embodiment. The engagement could also be effected by slipping the recess 214 onto the ledge 218, in the length direction of the recess, as is the case for all embodiments presented herein. When the element 200 is mounted an inner side 220 of the first end 206, said inner side 220 facing away from the second end 208, operatively abuts the backing plate 204 or the chute wall 206. An edge 222 between the inner side and the lower side of the first end is provided with a chamfer 222 in order to simplify the arrangement of the liner element 200 on the chute wall. The shape of the first end 206 provides stability in the mounted position, the inner side 220 operatively abutting the chute wall 202 securing that the lining element 200 does not rotate out of position during higher loads. Fig. 3 illustrates a chute wall 102 or a backing plate 104 provided with resilient chute lining elements 100 according to the first embodiment of the present invention. In use, material such as iron ore will be trans- ported, in a direction from top to bottom in Fig. 3, through the chute onto which the lining elements 100 are arranged. Small particulates in particular will be prone to adhere to the lining elements 100 forming build-ups. Such a build-up can block the chute, and if the build-up is not stopped it can also cause an "avalanche" when the build-up finally is released from the lining elements 100, which causes problems for consecutive processing devices. Using lining elements 100 the adhering material will be knocked away and the build-up stopped once par- ticulates with sufficiently large inertia hit the lining element carrying the adhered material. "Sufficiently large" implies sufficiently large to induce such a vibration of the lining element 100 that the adhered material falls of. The inertia can be caused by one particulate or by a group of particulates moving together, the feature being the impact on the lining element 100 rather than the size of the impacting particulates. A lining element 100 made of a softer material is generally easier to induce vibration to (if the dimensions are constant) , and thereby easier to remove material from in the above manner. This is true to a certain extent, after which the material gets too soft, in such a way that an impact only causes local vibrations rather than vibrations in the whole lining element. Generally, a softer material, at least when it comes to rubber and PU, has a larger abrasive strength and is therefore more preferred. Typical values regarding hardness of the main constituents of the lining element is below 80° Shore A, preferably below 60° Shore A and more preferably about 40° Shore A. Main con- stituents refers to the material constituting the largest part of the total volume of the lining element. This applies for all embodiments of the invention. In the following, alternative embodiments of the inventive lining element will be described referring to Figs. 4-7. Unless explicitly noted the general features of these embodiments correspond to the second embodiment and are given the same reference numbers, increased by 100, 200, and 300 respectively. The features are presented as compared to the first embodiment, but could equally well be added to an element 200 according to the second embodiment. Fig. 4 shows a lining element 300 according to a third embodiment. The lining element 300 according to this third embodiment comprises reinforcement rods 324 made of a harder/stiffer material, such as PC or any one previously described in relation to the armour elements. The purpose of the rods 324 is to induce rigidity in a direction parallel to the chute wall 302. This relates to the above drawback associated with the soft material. If a material impacts on a lining element 300 according to the third embodiment the rods 324 will assist in spread- ing the inertia and thus the resulting vibrations. The rods are depicted with a circular cross section. It should be noted that they optionally can be flat or have any other suitable shape. If the rods 324 have a length axis that is angled relative to the chute wall 302 the lining element 300 can be induced to flex asymmetrically, thus guiding material transported through the chute. Instead of being angled the rods 324 can have a cross section which varies along their length.

A fourth embodiment of a lining element 400 is shown in Fig. 5. Here, a ceramic tip coating 426 is arranged around the parts of the second end 408 that are exposed to the largest wear. The coating 426 increases the effective life-time of the lining element 400. By choosing the dimensions of the coating 426 it is possible to control the movement of the element 400. The coating 426 may for example be in one piece or divided into smaller pieces, which obviously affects the flexibility of the element 400.

In a fifth embodiment of the lining element 500, shown in Fig. 6, larger areas of the top face 510 are provided with a coating 528 comprising low friction material. These areas are known from empirical studies, experience, or calculation to be the ones exposed to the largest wear. The arrangement of a coating 528 thus prolongs the working lifetime of the chute element. In any one of the embodiments the main part of the lining element can be made out of a single material or consist of two or more different materials. A reason for combining materials is to increase stability, e.g., in the first end of the lining element, by incorporating a harder/stiffer material. This can be done by combination of PU and/or rubber of different hardnesses or by incorporation of inlays made of, e.g., PU and/or rubber as illustrated in Fig. 8. Further, the transition between the first and the second end (see e.g. Fig. 2), on the lower face of the lining element is generally smoother and the curvature of the transition can be laboured with in order to vary the vibrational characteristics of the lining element. Fig. 7 illustrates a lining element 600 having an inlay of a second material in the form of a stiffening plate 630.

Figs 8 and 9 respectively illustrate how the exact shape of the ledge 118 is not crucial for the function of the chute liner 100. The outer part of the ledge 118 basically serves as a carrier for the second snap locking means 116. Fig 8 further illustrates an example of a

"dual hardness" construction, in which the lining element comprises two materials. Generally, the first end 706 comprises a material having a hardness which exceeds the hardness for the material of the second end 708. This to ensure appropriate fastening properties and wear properties . It should be pointed out that the armouring elements as described above and in the appended claims would provide an surprising advantage over prior art systems even if applied to conventional lining elements, having a first end and a second end, wherein the first end is removably attached to a chute wall, or to a backing plate, by means of clamps, screws or other fastening means, that is lining elements having basically the same properties as the claimed one, but for the fastening means. Note that though the elements shown in the figures are composed of straight lines, this does not reflect the reality, but in a illustrative way. In use the elements will assume a form depending on the stiffness of the material, etc. It should also be emphasized that the shape of the L-shaped profile may be different. In the described embodiments the bottom part of the profile has a purpose of supporting the microledge from below, while the main purpose of the upwardly extending portion is to support the snap-lock means, this being the only contact point with the microledge. The upwardly extending portion, or shank, of the profile can consequently have various different shapes. Further the portion of the L- shaped profile that attaches to the chute wall or backing plate could include additional portions, such as an up- wardly extending portion (see Fig. 8), in order to improve stability or provide additional portions for arrangement of fastening elements. The profile will then be essentially U-shaped, which is considered to be comprised in the L-shape. The same goes for the alternative where a downwardly extending portion is added instead (see Fig. 9) , or as a complement to the upwardly extending portion mentioned above.

Claims

1. A resilient chute lining element having a first end and a second end, a top face and bottom face, said first end being adapted to be removably fixed to a chute surface and said second end extending away from said chute surface and being adapted to move freely in at least one direction cha ra ct e ri z e d in that said first end comprises first snap-locking means adapted to matingly engage second snap-locking means arranged on said chute surface.

2. The element of claim 1, wherein the element on an inner portion facing towards the chute surface comprises an abutment surface adapted to operatively abut the chute surface to prevent the element from rotating out of engagement with the snap-locking means .

3. The element of any preceding claim, wherein the element forms an integral unit.

4. The element of any preceding claim wherein the first snap-locking means comprises an elongate recess.

5. The element of claim 4, wherein the elongate recess extends parallel with said chute surface.

6. The element of claim 5, wherein the elongate recess is arranged on a side of the first end, said side facing away from the chute surface.

7. The element of claim 5, wherein the elongate recess is arranged on a bottom face of the first end.

8. The element of any preceding claim, wherein the element is made of a material comprising rubber.

9. The element of any one of the preceding claims 1- 7, wherein the element is made of a material comprising polyurethane .

10. The element of claim 8 or 9, wherein the material has a hardness below 80° Shore A, preferably below 60° Shore A and more preferably around 40° Shore A.

11. The element of any preceding claim, wherein the element is armoured with armour elements extending at least in a direction parallel to the chute surface.

12. The element of claim 11, wherein the armour elements comprise bars of a material chosen from the group consisting of: glass fibre, polyamide, rubber polyurethane and polycarbonate.

13. The element of claim 11 or 12, wherein the armour elements have a length axis extending in a direction forming an angle relative to the chute surface, so as to make the bending of a resilient lining element controllable in terms of direction.

14. The element of any preceding claim, further com- prising a wear portion arranged on the top face of the element, said wear portion comprising a material chosen from the group consisting of: alumina, zirconium, silicon oxide, steel, polyurethane, polyethylene, polyamide, polycarbonate or another low-friction material.

15. The element of any preceding claim, wherein the first end, on the side facing away from the chute surface, is chamfered.

16. Chute liner adapted to line a surface of a chute, comprising resilient chute lining elements in accordance with any one of the preceding claims .

17. Chute liner according to claim 16, wherein said second snap-locking means is operatively attached to the chute surface, said second snap-locking means comprising a longitudinal ledge having a free end extending essentially parallel with said chute surface, allowing the chute lining element to be mounted thereto by the first snap-locking means engaging the second snap-locking means .

18. Chute liner according to claim 17, wherein said free end extends essentially upwards.

19. Chute liner according to claim 17 or 18, wherein said ledge is L-shaped.

20. Chute liner according to any one of claims 17- 19, wherein the second snap-locking means has an L-shaped cross section with one portion operatively fastened to the chute wall with a first end, and with a second end projecting essentially perpendicular to the chute wall, and a second portion, extending upwardly from the second end, essentially parallel to the chute wall.

21. Use of a resilient chute liner element in accordance with any one of claims 1-16 for a chute, or a chute liner .

22. A method for fastening a chute liner to a chute liner wall comprising the steps of:

- fastening, directly or indirectly, an elongate ledge to the chute liner wall, said ledge having a longitudinal portion with a free end extending essentially parallel with said chute liner wall, said ledge forming a second snap-locking means,

- mounting a resilient chute lining element according to any one of claims 1-16 onto the elongate ledge by engaging the first snap-locking means of- the chute lining elements with the second snap-locking means of said ledge .

23. The method of claim 22, wherein the step of fas- tening the elongate ledge comprises the substeps of:

- fastening the ledge on a backing plate,

- fastening the backing plate to the chute surface.

24. The method of claim 22 or 23, wherein said elongate ledge has an essentially L-shaped cross section.