WO2007128068A1

WO2007128068A1 - Detecting worn wear plates

Info

Publication number: WO2007128068A1
Application number: PCT/AU2007/000604
Authority: WO
Inventors: Brian Davies
Original assignee: Brian Investments Pty Ltd
Current assignee: Brian Investments Pty Ltd
Priority date: 2006-05-05
Filing date: 2007-05-04
Publication date: 2007-11-15
Anticipated expiration: 2008-11-05
Also published as: AU2007247772A1

Abstract

ABSTRACT A wear indicator (30) comprises a head (32) subject to wear; a shaft (34) extending from the head; a passage (38) extending through the head and the shaft; and, a rod (40) positioned in the passage. The rod comprises a wear resistant portion (42) inside the head and an indicating portion (44) inside the shaft. The rod is moveable through the passage, in a direction away from the head, upon the head being worn away so as to project from an end (46) of the shaft thereby indicating the wear to the head.

Description

DETECTING WORN WEAR PLATES

Field of the Invention

The present invention relates to wear plates and detecting wear of these wear plates so that replacement of a worn wear plate can be effected in a timely manner.

Background of the Invention

Plates of hardened material are commonly used to minimize the effect of wear on structural elements of a piece of equipment. The material of the wear plates is selected for resistance to wear. Examples of equipment which use wear plates include hoppers, bins and chutes used in rock handling equipment or processing plants. This sort of equipment can be exposed to wear in the form of sliding and/or gouging abrasion. The wear plates act as a sacrificial element so that the plates are worn rather than the structural element of the equipment. The plates are exchanged once worn arid thus extend the working life of the equipment .

Difficulties arise in gauging the extent of wear of these wear plates because, for example, the plates are often in difficult to access positions, and the wear to the plates is often uneven. It is consequently difficult to determine the exact timing of a wear plate change out because it is desirable to use the wear plate to the maximum extent of its life but not to the extent of failure. The applicant's International Patent Application number PCT/AU2006/00121 describes a wear sensor useful to detect wear of a wear plate . The present invention relates to improvements to and/or uses of this wear sensor. Brief Summary of the Invention

In accordance with a first aspect of the present invention there is provided a wear indicator comprising: a head subject to wear; a shaft extending from the head; a passage extending through the head and the shaft; and, a rod positioned in the passage, wherein the rod comprises a wear resistant portion inside the head and an indicating portion inside the shaft, wherein the rod is moveable through the passage, in a direction away from the head, upon the head being worn away so as to project from an end of the shaft thereby indicating the wear to the head.

The wear indicator is typically formed into a bolt by the shaft being provided with an external thread.

The projection of the rod from the end of the shaft provides a visual indication of the extent of wear of the head. The head is arranged so that the wear is related to the wear of a wear plate in which wear indicator is engaged.

In an embodiment the indicating portion of the rod is configured to indicate the extent of wear to the head.

In an embodiment the extent of wear of the head is indicated by a length of rod that projects from the end of the shaft. In another embodiment the extent of wear to the head is indicated by the rod being configured to have different colours at certain positions along the length of the indicating portion, so that the extent of wear is indicated by the colour of the rod that projects from the end of the shaft . — ^ —

In another embodiment the extent of wear to the head is indicated by markings disposed on the indicating portion of the shaft so that as the rod projects from the end of the shaft, the markings indicate the extent of wear to the head.

In one embodiment the wear indicator is arranged relative to the wear plate so that the end of the shaft from which the rod projects is opposite to the head.

According to a second aspect of the present invention there is provided a method of indicating wear to a wear plate comprising providing a wear indicator as defined above, where the head is located in the wear plate and the extent of the wear to the wear plate is reflected in wear to the head, so that as the wear plate wears, the rod indicates wear of the wear plate .

According to a third aspect of the present invention, there is provided a wear plate change out method comprising: providing an apparatus with a plurality of wear plates inside a structural element of a piece of equipment ; providing each wear plate with one or more wear indicators which indicate wear to the respective wear plate to a person outside of the structural element; and, indicating on the exterior of the apparatus an association between the wear indicators of the wear plates so that upon one or more wear indicators indicating that one or more wear plates are worn to the extent that they need replacement, the correct wear plates for replacement can be identified without internal inspection of the structural element. In one embodiment the indication on the exterior of the structural element of the association between the wear indicators and the wear plates is by associating a serial number of the wear indicator with a serial number of the wear plate .

In one embodiment a serial number may be indicated by placing a bar code adjacent to the wear indicator. In one embodiment the association is recorded in a database between the wear plate serial number and the bar code.

In one embodiment indicating the association between the wear indicators and the wear plates is conducted by marking an outline of the wear plate on the exterior surface of the structural element such that the wear indicators associated with each wear plate fall within the outline of the wear plate.

Brief Description of the Drawings

In order to provide a better understanding of the present invention preferred embodiments will now described in greater detail, by way of example only, with reference to the accompanied drawings, in which: Figure 1 is schematic perspective view of a bin lined with wear plates and installed with wear indicators according to an embodiment of the present invention;

Figure 2 is a schematic side elevation of a side of the bin of Figure 1 ; Figure 3A is a schematic side elevation of a wear indicator in the form of a bolt according to an embodiment of the present invention;

Figure 3B is a cross sectional side elevation through the section (A-A) of Figure 3A; Figure 3C is a schematic cross section 91 of a side elevation through the section (A-A) of Figure 3A, where the bolt head has been subjected to some wear; Figure 3D is a schematic cross sectional side elevation through the section (A-A) of Figure 3A showing further wear over that shown in Figure 3C;

Figure 4A is a schematic cross sectional side elevation showing an alternative wear indicator in the form of a bolt and in accordance with an embodiment of the present invention; and,

Figure 4B is a schematic cross sectional side elevation of the bolt in Figure 4A having been subjected to wear.

Detailed Description of Preferred Embodiments

Referring to Figure 1 there is shown a schematic representation of a piece of equipment having structural elements lined with wear plates 14, 16 & 18. For this example the equipment is a bin 10. The bin 10 comprises a number of sides (in this case four) including side 12. The wear plates 14, 16 & 18 line the inside of the bin 10 so as to protect the bin from wear through abrasion from rocks etc impacting on or moving across the sides of the bin 10. Side 12 is shown in more detail in Figure 2.

Due the shape of the bin 10, the wear plates are required in different shapes and sizes. For examples wear plate 14 is a standard rectangular shape and is replicated many- times on the side 12. However other shapes and sizes of wear plates including plates 16 and 18 are also required to protect the side 12 of the bin 10. Additionally wear plates of different hardness/material may be used. It is therefore necessary to identify individual wear plates for replacement due to wear not being consistent across all of the wear plates and to identify the correct size, shape and other characteristics of a replacement wear plate.

The wear plates are secured by use of bolts . In this application, the bolts also double as wear indicators, although the bolts need not be in the ' form of a wear indicator. Separate wear indicators (not in the form of bolts) may be provided. Each wear plate is secured by at least one bolt 20, 22 and 24 respectively for wear plates 14, 16 and 18. Typically, each wear plate is secured by four bolts . By measuring the wear by use of one or more wear indicators for each wear plate the extent of wear of the corresponding plate can be determined and when necessary the wear plate can be replaced with a new wear plate.

Because the wear plates are located on the inside of the bin it is usually very difficult to get access and the equipment must be shut down. The present invention allows a person to determine the wear on wear plates externally to the bin and to identify which wear plates in need of replacing so that a correctly sized and shaped replacement of the correct hardness is ready so as to reduce downtime.

Figure 2 also represents an external view of the bin 10 which has wear indicators protruding through the bin wall so as to provide an indication of the extent of wear externally from the bin 10. Thus, the wear plates that need replacing can be assessed from outside of the bin 10 by associating each wear indicator (e.g. both 22) with a particular wear plate (e.g. plate 16) so that when a wear indicator indicates that the wear plate requires replacement, then the corresponding wear plate can be identified. This may be, for example, by providing a serial number for each wear indicator and for each wear plate and recording this association between the wear plate and the four (or which ever number is appropriate) wear indicators. This can be extended further by fixing a bar code, or some other appropriate means readable by an electronic reading apparatus adjacent to the wear indicator. This is so that when a wear indicator indicates that the wear plate requires replacement, then the adjacent bar code can be scanned. The wear plate identification can be automatically looked up so that both the location of the wear plate can be identified and its appropriate replacement are ordered.

Alternatively, or in addition, an outline of the wear plates can be placed on the external surface of the bin 10 so that those wear indicators that fall inside the perimeter of the outline of a wear plate can be used to determine which type of wear plate requires replacement as well as the location of the wear plate. It is particularly useful when both methods are combined to verify the reading of the indictors (by reading them as a group) and/or to gauge where the wear is occurring with in the bin. This may indicate that re-design of the bin may be appropriate or that particular areas of the bin require harder wear plates which are more resistant to wear.

A database can be used to track the extent of the wear of the wear plates over time so that it is easier to order replacement wear plates and so that stock can be kept at efficient levels. This process can also be used to automate ordering of new wear plates . The database could additionally be used where the amount of wear is indicated by the wear indicator so that for example the amount of wear over a course of time can be recorded. For example the amount of millimeters of wear or percentages or fractions of wear (say, for example, when the wear plate is one quarter worn) can be recorded every day/week/month, as appropriate. A report can, for example, be produced when wear plate is quarter-worn, half-worn, and three- quarters worn. Naturally, other scales can be used.

Referring to Figure 3A to 3D, a wear indicator 30 is shown which is suitable for use with the bin in Figures 1 and 2.

In this embodiment the wear indicator in the form of a bolt. The bolt 30 has a head 32 used to secure the wear plate to the support structural and a shaft 34. The shaft is provided with thread 36 so that it can function as a bolt. The head 32 has a thickness indicated as 40. The bolt 30 has a hollow passageway 38 extending through its length from the surface 32 of the head 30 to the end of the shaft 46. Inside the passage 38 is a rod 40 which includes a wear resistance portion 42 and an indicating portion 44. The wear resisting portion 42 is preferably formed of tungsten carbide and is extremely hard and very resistant to wear. Other suitable materials may also be used. The indicating portion may be for example formed of a softer material such as plastics, metal or wood. The rod 44 is arranged to be able to move through the passage 38. Preferably it is snuggly fitting so that is will not readily fall out. In use, as indicated by Figure 3C, as the surface 56 of the head 32 is worn away, due to its hardness is not substantially worn. Instead the wear resistant portion 42 is urged into the passage 38, thereby pushing the indicating portion 38 so that it advances so that a portion 54 projects from the hole 48 at end 46. The amount of movement of the wear resistant portion is indicated by 52, this will correspond to the amount indicated by 50 that projects from the end 56.

As can be seen in Figure 3D, as the extent of wear of surface 56' increases the movement of the wear resistant portion as shown by 52 ' increases and thus the extent of projection of indicating portion 44 extends as shown by 50' .

It is preferred that the rod 40 be exactly the same length as the passage 38 that extends through the bolt 30, although this need not be the case . It is also intended that the wear indicating portion 42 be fixed to the indicating portion 38, but this may not necessarily be the case. Instead the wear indicating portion 42 may simply abut against the indicating portion 38. Referring to Figures 4A and 4B, an alternative embodiment of a wear indicator 60 is shown. The wear indicator 60 comprises a head 62 and a shaft 64. Again similar to the previous embodiment, this wear indicator 60 is in the form of a bolt and has external thread 66 substantially along the length of the shaft 64. The bolt 60 has a passage 68 extending through its length. The passage 60 includes an expanded portion 90, which is provided adjacent the end 76 of the bolt 60. The expanded portion 90 opens at 78. A rod 70 is located within passage 68.

In this embodiment, the rod 70 comprises a wear resistant portion 72, indicating portion 74 and connecting portion 92 that connects and extends between the wear resistant portion 72 and the wear indicating portion 74. Indicating portion 74 is of a larger radius that the connecting portion 92 but still fits within the expanded diameter of the portion 90. As shown in Figure 4B, as the surface 86 of the head 62 of the bolt 60 is worn, the indicating portion 74 projects from the end 76 of the shaft 64. In this embodiment a protective cap 94 is provided which has an internal thread 96 that screws onto the thread 66 of the shaft 64, and a hollow portion 96 which receives the indicating portion 74 as it projects from the end 76 of the shaft 64. The protective cap 94 may be removed to check the extent of wear by viewing the indicating portion 74 or it may be clear/transparent so that it need not be removed. The indicating portion 74 is provided with a series of indications 84 which may be in the form of, for example, lines that measure the distance in millimeters. Alternatively, the indications 84 may be in the form of colours so that the extent of wear can be shown according to the colour able to be seen.

Modifications and variations may be made in the present invention without departing from the base inventive concept. Modifications and variations as will be apparent to the skill addressed will be regarded as falling within the scope of the present invention.

Claims

1. A wear indicator comprising: a head subject to wear; a shaft extending from the head; a passage extending through the head and the shaft; and, a rod positioned in the passage, wherein the rod comprises a wear resistant portion inside the head and an indicating portion inside the shaft, wherein the rod is moveable through the passage, in a direction away from the head, upon the head being worn away so as to project from an end of the shaft thereby indicating the wear to the head.

2. A wear indicator as claimed in claim 1, wherein the shaft is provided with an external thread.

3. A wear indicator as claimed in either claim 1 or 2, wherein in use projection of the rod from the end of the shaft provides a visual indication of the extent of wear of the head.

4. A wear indicator as claimed in any one of claims 1 to 3, wherein the head is arranged so that the wear is related to the wear of a wear plate in which wear indicator is engaged.

5. A wear indicator as claimed in claim 1 to 4 , wherein the extent of wear of the head is indicated by a length of rod that projects from the end of the shaft.

6. A wear indicator as claimed in claim 1 to 4 , wherein the extent of wear to the head is indicated by the rod being configured to have different colours at certain positions along the length of the indicating portion, so that the extent of wear is indicated by the colour of the rod that projects from the end of the shaft.

7. A wear indicator as claimed in claim 1 to 4 , wherein the extent of wear to the head is indicated by markings disposed on the indicating portion of the shaft so that as the rod projects from the end of the shaft, the markings indicate the extent of wear to the head.

8. A method of indicating wear to a wear plate comprising providing a wear indicator as defined above, where the head is located in the wear plate and the extent of the wear to the wear plate is reflected in wear to the head, so that as the wear plate wears, the rod indicates wear of the wear plate .

9. A wear plate change out method comprising: providing an apparatus with a plurality of wear plates inside a structural element of a piece of equipment ; providing each wear plate with one or more wear indicators which indicate wear to the respective wear plate to a person outside of the structural element; and, indicating on the exterior of the apparatus an association between the wear indicators of the wear plates so that upon one or more wear indicators indicating that one or more wear plates are worn to the extent that they need replacement, the correct wear plates for replacement can be identified without internal inspection of the structural element.

10. A method as claimed in claim 9, wherein the indication on the exterior of the structural element of the association between the wear indicators and the wear plates is by associating a serial number of the wear indicator with a serial number of the wear plate.

11. A method as claimed in claim 10, wherein the serial number may be indicated by placing a bar code adjacent to the wear indicator.

12. A method as claimed in claim 10 or 11, wherein the association is recorded in a database between the wear plate serial number and the bar code .

13. A method as claimed in claim 9 to 12, wherein indicating the association between the wear indicators and the wear plates is conducted by marking an outline of the wear plate on the exterior surface of the structural element such that the wear indicators associated with each wear plate fall within the outline of the wear plate.