Centraliser segment and centraliser

Abstract

A centraliser segment (11) which can, by itself or in combination with one or more corresponding centraliser segments, be used to form a centraliser (13) which can in use be clampingly engaged around an element (10) which is receivable in a borehole, said centraliser segment comprising a first collar portion (15), a second collar portion (17) and at least one bow element (19) extending between said first collar portion and said second collar portion to maintain the collar portions in spaced relation to each other, wherein the collars have an inner face which in use is to bear against the element and wherein said bow element has a curvature along its length to define an intermediate portion which extends laterally from the centraliser segment away from the inner faces of the collars, at least the intermediate portion of the bow elements having a convex transverse profile, a first connection element (21) provided at one end of the collar portions and second connection element (23) provided at the other end of the collar portions, wherein in use said first connection element are engagable with said second connection element of the same or another centraliser segment such that one or more said centraliser segments are connectable together to form a centraliser which in use is capable of being received around the element whereby the intermediate portions are radially outermost, said first and second connection element having an adjustment means which can cause the diameter of the centraliser to be varied.

Description

RELATED APPLICATIONS[0001]This application is a continuation-in-part of PCT / AU2009 / 000268 filed on Mar. 5, 2009, which claims priority to Australian patent application number 2008901065 filed on Mar. 5, 2008. The contents of each of these applications is incorporated herein by reference in their entirety.FIELD OF THE INVENTION[0002]The present invention relates to a centraliser segment and a centraliser formed of one or more of such centraliser segments. The centraliser can be used with items to be located within a borehole such as rock bolts and soil nails.BACKGROUND[0003]One application of the centraliser is to centralise a rock bolt. A centraliser which has been previously proposed by the inventor and which could be used to centralise borehole casings and rock bolts is disclosed in AU200143778. The centraliser elements of the above patent specification incorporated a connection element which required the use of a specialised tool in causing the movement between the connection ele...

AI Technical Summary

Benefits of technology

[0006]In accordance with one aspect of the present invention, there is provided a centraliser segment which can, by itself or in combination with one or more corresponding centraliser segments, be used to form a centraliser which can in use be clampingly engaged around an element which is receivable in a borehole, said centraliser segment comprising a first collar portion, a second collar portion and at least one strap like resiliently flexible bow element extending between said first collar portion and said second collar portion to maintain the collar portions in spaced relation to each other, wherein the collars have an inner face which in use is to bear against the element and wherein said at least one bow element has a curvature along its length to define an intermediate portion which extends laterally from the centraliser segment away from the inner faces of the collars, said bow elements being resiliently flexible and each bow element having a convex transverse profile and having a varied width along their length which is greatest at the central intermediate portion, a first connection element provided at one end of the collar portions and second connection element provided at the other end of the collar portions, wherein in use said first connection element are engagable with said second connection element of the same or another centraliser segment such that one or more said centraliser segments are connectable together to form a centraliser which in use is capable of being received around the element whereby the intermediate portions are radially outermost, said first and second connection element having an adjustment means which can cause the diameter of the centraliser to be varied.

Problems solved by technology

While the centraliser elements of the form referred to above can be very advantageous when used with pipes or casings they present problems when applied to elements of smaller diameter such as rock bolts and soil nails

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