WO2009025603A1

WO2009025603A1 - A reamer

Info

Publication number: WO2009025603A1
Application number: PCT/SE2008/000440
Authority: WO
Inventors: Andrew Bell; Raymond Purser; Neil Weber; Antony Harry Hardy
Original assignee: Sandvik Intellectual Property Ab
Priority date: 2007-08-23
Filing date: 2008-07-09
Publication date: 2009-02-26
Also published as: CL2008002463A1; AU2007211901B2; AU2007211901A1

Abstract

A reamer for a core drill is described which includes a wear indicator which is arranged to provide an indication of the degree of wear of the reamer. The wear indicator may be provided in the form of a recess provided in an area of wear resistant material. The invention also includes a method of forming a reamer.

Description

A REAMER

Technical Field

This invention relates to a reamer and particularly to a reamer used in core drilling.

Background to the Invention

A reamer tool is used in the retrieval of core samples for mining and geotechnical surveys. It is located behind and joined to a core bit via a threaded connection. The reamers functions include; maintenance of the hole diameter and to prevent hole deviation. Through the effects of wear from contact with the rock the initial outer diameter (OD) will reduce in size with use.

The core bit OD is designed and specified to be smaller than that of the reamers OD. Through continued and unchecked wear, the reamers OD can be at or smaller than that of the core bit, resulting in increased wear and reduced bit life. Lack of maintaining hole diameter can result in additional "work" being undertaken by a new reamer and bit in the same drilled section, reducing productivity and increasing costs.

It has been tried to check the wear of the reamer by the use of go and no-go ring gauges. If the inspection frequency is inappropriate, or gauges are lost or out of specification then an undersize reamer may unintentionally be used in a drilling operation leading to the drawbacks foreshadowed above.

Summary of the Invention

In a first aspect the present invention provides a reamer suitable for use in a core drilling operation and including a wear indicator which is arranged to provide an indication of the degree of wear of the reamer.

The reamer may have a reaming region which effects the reaming operation and the wear indicator is associated with the reaming region. The indicator may be a visual indicator and a change in the appearance of the indicator indicates the degree of wear.

The change in the appearance of the indicator may include a change of colour of the indicator. The wear indicator may be in the form of a recess provided in an area of wear resistant material.

The wear indicator may be in the form of an indicator element provided in an area of wear resistant material, the element being formed from a material which is of a different appearance to the wear resistant material. The reamer may include several wear indicators spaced about the reamer.

In a second aspect the resent invention provides a drill bit including a reamer according to the first aspect of the invention.

In a third aspect the present invention provides a method of forming a reamer including the step of placing a consumable element into a mould and forming the reaming region of the reamer in the mould; and removing the consumable element to leave at least one recess in the reaming region.

The method may include the step of applying a layer of paint to the at least one recess. The method may include the step of applying two layers of paints of differing colours to the at least one recess.

Brief Description of the Drawings

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a reamer assembly including a reamer according to an embodiment of the present invention;

Figure 2 is a cross-sectional view of the reaming assembly of figure 1 along the line A-A of figure 3; Figure 3 is an end view of the reamer assembly of figure 1 ;

Figure 4 is a cross-sectional view of the reaming assembly of figure 1 shown in a bore;

Figure 5 is a partial sectional side view of the reamer of figure 1 being worn and within specification; and Figure 6 is a partial sectional side view of another embodiment of the invention. Detailed Description of the Preferred Embodiment

Referring to Figures 1 to 3, a reamer assembly is shown including reamer 10 which is in screw-threaded engagement with a conventional core bit 20 by way of threaded joint 24. Reamer 10 includes a steel body 11 to which is attached a reaming region formed from wear resistant material 12. Several recesses 14, of which two are visible, are evenly spaced about the outer circumference of the reaming region. Bit 20 includes a cutting formation 22 for cutting into rock and the like. Waterways 15 are provided for the passage of drilling fluids in use.

In order to form reamer 10, the steel body 11 is placed in a mould. Four consumable strips are then prepared which each have a symbol stamped into them. The consumable strips are then placed in the mould which is then packed with powdered wear resistant material. The strips are oriented so that they lie against the wall of the mould with the stamped symbols being in contact with the powdered material. A sintering or liquid metal infiltration operation is then carried out. Following this, the consumable strips are removed. The symbols that were stamped into the strips cause a small embossed portion of wear resistant material to be formed in the recess left by each consumable strip.

Referring to figure 4, the reamer assembly is shown in a bore in a rock formation part way through a drilling operation. A core 30 has begun to form inside the assembly. As can be seen, the wear resistant material 12 which forms the reaming portion constitutes the maximum outer diameter of the assembly and, as the bore is formed during drilling, this ensures that the diameter of the bore is uniform.

Referring to figure 5, the reamer is shown in partial cross-sectional view after a period of use. The reamer is worn and the portions of wear resistant material labelled B have been worn away during use. The lower specification limit of the reamer is the distance indicated by arrow A. The reamer shown in figure 5 is still within specification as the wear resistant material extends beyond the distance A. The embossed portion 18 formed by the stamped portion of the consumable strip is still present in recess 14. This gives a visual indicates that the reamer is still within specification. When the embossed portion 18 is no longer visible, this indicates that the reamer is out of specification and should be replaced. Referring to figure 6, an alternative embodiment of a reamer 100 is shown. In this embodiment, an indicator element in the form of steel protuberance 114 is provided. The steel is of a different appearance to the wear resistant material. When reaming region 112 is worn to the extent where protuberance 114 is visible then this indicates that the reamer is worn out of specification.

In other embodiments a coloured indicator is provided. A recess at the gauge diameter of the reamer is created by the insertion of a consumable strip of material within a mould in a similar fashion to the method described above. After casting, the strip of material is removed to create a recess at or around the lower wear specification. A paint is then be applied to the recess, which when removed identifies that the reamer is worn out. In another embodiment, two layers of different coloured paint can be applied to a region in or around the recess. On removal of the upper layer of paint the lower-Out of specification¹ colour is exposed.

In another embodiment, an indicator element is provided in the form of a layer of steel provided in the wear resistant material to a predetermined depth. If the steel layer is not visible at the reaming surface upon making a visual inspection, then this indicates that it has been worn away and the reamer should be replaced.

In the embodiment described above, the reamer was provided as a separate component removable from the drill bit. In another embodiment, the reamer is provided on the drill bit itself.

Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention. The disclosures in the Australian patent application No. 2007211901 , from which this application claims priority, are incorporated herein by reference.

Claims

1. A reamer suitable for use in a core drilling operation and including a wear indicator which is arranged to provide an indication of the degree of wear of the reamer.

2. A reamer according to claim 1 wherein the reamer has a reaming region which effects the reaming operation and the wear indicator is associated with the reaming region.

3. A reamer according to either claim 1 or claim 2 wherein the indicator is a visual indicator and a change in the appearance of the indicator indicates the degree of wear.

4. A reamer according to claim 3 wherein the change in the appearance of the indicator includes a change of colour of the indicator.

5. A reamer according to either of claim 1 or claim 2 wherein the wear indicator includes a recess provided in an area of wear resistant material.

6. A reamer according to either of claim 1 or claim 2 wherein the wear indicator includes an indicator element provided in an area of wear resistant material, the element being formed from a material which is of a different appearance to the wear resistant material.

7. A reamer according to any preceding claim wherein several wear indicators are spaced about the reamer.

8. A drill bit including a reamer according to any one of claims 1 to 7.

9. A method of forming a reamer including the step of placing a consumable element into a mould and forming the reaming region of the reamer in the mould; and removing the consumable element to leave a recess in the reaming region.

10. A method according to claim 9 further including the step of applying a layer of paint to the recess.

11. A method according to claim 9 further including the step of applying two layers of paints of differing colours to the recess.