GB2248303A - Non-destructive testing probe - Google Patents

Abstract

A probe for inspecting the interior surface of tubular goods has a probe end 19 for making contact with the surface being inspected. The probe end 19 is housed in one end region of a body, the other end region of which is grasped by the user to manoeuvre the probe into the pipe 11. The probe body is an elongate body which is long enough for the user to probe the region of the pipe 11 interior intermediate the pin end 12 and the box end 13. The probe-end 19 projects approximately at right angles to the axis of the probe body, and is housed in a resiliently movable manner 21 in the probe body so as to be urged into contact with the pipe 11 interior. The probe-end-housing region 16, 17, 18 of the probe body is enlarged in diameter with respect to the rest of the body and is adapted to be moved about the interior of the pipe 11 and maintain contact with the pipe 11 interior surface to act as a datum for the probe-end 19 movements. <IMAGE>

Description

NDT PROBE Field of the Invention The invention relates to non-distructive testing (NDT) probes of the dffer.ntitl transmit and receive (DTR) kind.

State of the Art Probes of this kind are known in several different embodiments.

One such probe is the "WeldScan" probe currently marketed in the United Kingdom by Hocking NDT Limited of St. Albans, Hertfordshire. The WeldScan probe is intended primarily ror in-use inspection of ferrous steel welds as an alternative to the traditional magnetic particle inspection method. It can detect surface-breaking fatigue cracks through up to 2 mm.

of surface coati- material and it operates typically over a range of frequencies around 100 kHz and in conjunction with a Hocking AV1OB portable eddy current display screen instrument.

The WeldScan probe has a probe-end which is rounded, so as to make essentially single-point contact with the surface being inspected. The probe-end is housed in one end region of a body, the other end region of which is grasped by the user to manoeuvre the probe around the surface being inspected.

The probe-end can project approximately in line with the axis of the probe body or it can project approximately at right angles to it.

This known WeldScan probe is effective, but it has limitations.

Its body, although elongate, is of limited length. In particular, it is not long enough to allow a user to insert the probe from the pin-end of a drill string pipe and traverse the upset between the pin-end and the bo:c-end to probe the pipe interior beyond that upset.

Anothet known unit is the American AMF "Tuboscope" which is an electromagnetic unit . This has a number of drawbacks of its own. Firstly, the pipe needs to be magnetised.

Secondlv, the probe can only pick up single-orientation defects.

It is a general object of this present invention to provide an NDT probe which is particularly adapted for inspecting the interior surfaces of oil country tubular goods such as, for example, casing, tubing and drill pipe strings; which is of the DTR kind and can take advantage of the known plus points of that kind of probe; and which, in use, can better the above and other limitations of the AMF style unit.

Summary of the Invention An NDT probe of the DTR kind, adapted for inspecting the interior surfaces of oil country tubular goods; the probe end making contact aLLd with the surface being inspected,ieoge,ssbeing housed in one end region of a body, the other end region of which is grasped by the user to manoeuvre the probe into the pipe when in use; characterised by the feautres, firstly, that the probe body is an elongate body which is long enough for the user to probe the region of the pipe interior intermediate the pin end and the box end of the pipe; secondly, by the feature - known per se - that the probe-end projects approximately at right angles to the axis of the probe body; thirdly; by the feature that the probe-end is housed in a resiliently movable manner in the probe body so as to be urged into contact with the pipe interior in use; and fourthly, by the feature that the probe-end-housing region of the probe body is enlarged in diameter with respect to the rest of the body and is adapted to be moved about the interior of the pipe and maintain contact with the pipe interior surface to act as a datum for the probe-end movements.

Advantageously the probe-end-housing region of the probe body is wholly or partly cylindrical - preferably circular-cylindrical - to facilitate its movement about the tube interior, the probeend projecting approximately at right angles from the cylinder axis, and the cylinder being small enough to allow the probe to be inserted from the pin-end of the pipe and traverse any upset between the pin-end and the box-end to probe the pipe interior beyond that upset.

Such a probe can pick up all pipe defects - corrosion pits, internal ridges, cracks - and when used in conjunction with a suitable display-screen instrument it can also distinguish between these three different kinds of defect on the screen.

It is relatively unaffected by the internal condition of the pipe, whether wet or dry..

And it is just as useful in picking out and pin-pointing defects in the internal plastics coating of (for example) drill string pipe work as it is in pin-pointing and delineating defects in the pipe work and/or the pipe work welds.

Description of the Preferred Embodiment The probe illustrated in the drawing is shown inspecting theinterior surface of a drill string pipe 11 which is conventionally circular-cylindrical, has a pin-end 12 and a box-end 13, and is upset internally at 14.

The probe has been inserted from the pin-end 12 of the pipe and traversed the upset 14 to probe the pipe interior beyond that upset.

The major part of the probe body consists of an elongate circularcylindrical tube 15 which is long enough for the probe to be inserted in the way just described by the user, traverse the upset, and probe the region of the pipe 11 shown. Mounted concentrically with this body 15 is a probe-end-housing region 16 which is also circular-cylindrical and which, as illustrated, has respective opposite-end portions of increased diameter.

Another circular-cylindrical portion 17 forms an extension of the prope-end-housing 16, and a third such portion 18 is mounted on the end of it. All three portions 16, 17 and 18 are mounted concentrically on the same axis and the end most portion 18 is identical to the probe-end-housing 16 but for the fact that it houses no probe-end.

The probe-end itself is referenced 19. As shown, it projects at right angles from the axis of the probe body 15 through 18. It is mounted in the probe-end housing 16 in such a manner as to be resiliently movable in the housing and to be urged into contact with the wall of the pipe 11 by a coiled compression spring 21.

The enlarged-diameter opposite-end regions of the housing 16 serve two purposes. They enable the housing to be moved about the interior of the pipe 11 so as to inspect the whole of the surface area thereof. And, as long as contact is maintained with the pipe interior surface, they act as a datum for the probe-end movements. As long as the user maintains firm pressure on the probe body, so as to keep the probe end housing 16 in contact with the interior surface of the pipe 11, he can be satisfied that the probe 19 is also being kept in constant contact with the pipe interior. He need not worry about exerting the right pressure because, of course, if he did not have the housing 16 to act as the necessary datum, the pressure he exerted would inevitably vary and this would affect the readings given by the probe.

The electrical lead 22 from the probe emerges from the housing 16 and runs along the surface of the body 15 as shown. Alternatively, since the body 15 is a tube, it could come out along the inside of that tube as indicated in chain line at 22A.

This latter option would have the advantage of minimising the effective diametral envelope of the probe as a whole.

The probe-end 19 can be constructed in known manner, and could, for example, comprise one of the Hocking NDT WeldScan probes previously referred to. And it could be used in conjunction with the Hocking AV1OB portable screen-display instrument also mentioned above or with any other equivalent instrument.

The particular construction described and illustrated, amongst other advantages, gives the user the option of moving either the pipe or the probe in order to traverse the whole of the surface being inspected.

It can also probe the whole of the pipe interior whereas the known probes are effectively "end-region only" probes. The AMF "Tuboscope", for example, can only manage to probe about 18. ins. worth (approximately 38 cms. ) of the length of a pipe from the pipe open end. And it is not, strictly speaking, a probe. In current state-of-the-art terminology it is a shoe.

It certainly cannot follow the internal contours of pipe bores as the described and illustrated probe can.

A modification to the above-described and illustrated probe which enhances performance of the probe in following the countours of the surface being inspected involves provision of a pair of articulated joints in the probe end housing 16, one on each side of the probe end 19. These joints are preferably knuckle joints.

Such joints are especially useful for facilitating inspection of the bores of drill string pipework having upsets.

Claims (10)

CLAIMS:

1. An NDT probe of the DTR kind, adapted for inspecting the interior surfaces of oil country tubular goods; the probe end making contact with the surface being inspected, in use, and being housed in one end region of a body, the other end region of which is grasped by the user to manoeuvre the probe into the pipe when in use; characterised by the features, firstly, that the probe body is an elongate body which is long enough for the user to probe the region of the pipe interior intermediate the pin end and the box end of the pipe; secondly, by the feature that the probe-end projects approximately at right angles to the axis of the probe body; thirdly, by the feature that the probe-end is housed in a resiliently movable manner in the probe body so as to be urged into contact with the pipe interior in use; and fourthly, by the feature that the probe-end-housing region of the probe body is enlarged in diameter with respect to the rest of the body and is adapted to be moved about the interior of the pipe and maintain contact with the pipe interior surface to act as a datum for the probe-end movements.

2. A probe as claimed in Claim 1, wherein the probe-end-housing region of the probe body is wholly or partly cylindrical.

3. A probe as claimed in Claim 2 wherein the probe-end-housing region is circular-cylindrical.

4. A probe as claimed in Claim 2 or Claim 3 wherein the probeend-housing region is small enough to allow the probe to be inserted from the pin-end of the pipe and transverse the upset between the pin-end and the box-end, where such an upset is present, to probe the pipe interior beyond that upset.

5. A probe as claimed in any preceding Claim, wherein the probeend is resiliently biased outwardly from the probe body by a coiled compression spring.

6. A probe as claimed in any preceding Claim wherein the probeend-housing region of the probe body has enlarged diameter opposite end regions.

7. A probe as claimed in any preceding Claim wherein the probe body is hollow and the electrical leads from the probe end are housed in the interior of the probe body.

8. A probe as claimed in any preceding Claim wherein the probeend-housing region has a pair of articulated joints, one on each side of the probe end.

9. A probe as claimed in Claim 8 wherein the articulated joints are knuckle joints.

10. An NDT probe of the DTR kind substantially as described herein with reference to the accompanying drawings.