GB2182445A

GB2182445A - Apparatus for non-destructive testing

Info

Publication number: GB2182445A
Application number: GB08623122A
Authority: GB
Inventors: Colin Seward; Stephen Geoffrey Drake
Original assignee: OILFIELD INSPECTION SERVICES
Current assignee: OILFIELD INSPECTION SERVICES
Priority date: 1985-09-30
Filing date: 1986-09-25
Publication date: 1987-05-13
Also published as: GB2182445B; GB8524069D0; GB8623122D0

Abstract

Apparatus for use in testing by magnetic particle inspection comprises a body 11 at least two parallel lengths of flexible, insulated, electric cable 14, and means 12 connecting said lengths to the body whereby, when the body is moved towards a convex surface of an article to be tested, the lengths both contact the article and deflect to conform with said convex surface. The necessary magnetic field is induced by electric current flowing through the cable. The spacing of the cables may be adjustable by arms 23 actuated by hydraulic cylinder 20 and ram 21. The cable are mounted on pivoted arms 12, biassed by springs 17 to hold the cable taut. The apparatus may incorporate sprays 25 for magnetic ink, UV lamps 26 and a TV camera 27, and is intended for use underwater. <IMAGE>

Description

SPECIFICATION Apparatus for non-destructive testing This invention is concerned with apparatus for non-destructive testing and, more particularly, with apparatus for non-destructive testing by magnetic particle inspection.

In magnetic particle inspection, a magnetic flux is caused to flow in an article (e.g. a steel pipe) being tested and defects in the article are indicated by magnetic particles distributed over the surface of the article, e.g. in the form of magnetic ink. Various means such as electromagnets and pipe-encircling current-carrying coils have been proposed for inducing the necessary magnetic field in the article.

It is an object of the present invention to provide means for simply and effectively inducing the magnetic field in an article being tested by magnetic particle inspection, particularly but not exclusively in an underwater location.

According to the invention, apparatus for use in testing by magnetic particle inspection comprises a body, at least two parallel lengths of flexible, insulated, electric cable, and means connecting said lengths to the body whereby.

when the body is moved towards a convex surface of an article to be tested, the lengths both contact the article and deflect to conform with said convex surface.

Said lengths of cable are preferably different parts of a single cable.

Said connecting means may comprise arms to which said lengths are clamped and which are pivoted on the body. The arms are prefer abiy spring-ioaded to apply tension to said lengths.

Preferably, means are provided for moving said lengths towards and away from each other to adjust the distance between them.

Thereby, the lengths can be introduced to a desired distance into a nodal intersection of an article to be tested. The aforesaid arms may, for example, be mounted on supports which are pivoted on said body and which are movable towards and away from each other, e.g. by operation of an hydraulic ram connected to the supports by linkages.

The body preferably carries a plurality of fluid dispensing outlets arranged in an arcuate array so as each to be adjacent to a convex surface of an article to be tested when the lengths of cable conform to said surface.

The body preferably also carries an ultraviolet lamp and TV camera, as well as any other desired equipment, e.g. a transformer and rectifier.

Desirably, the body is provided with a handle.

The following is a description, by way of example, of an embodiment of the invention, reference being made to the accompanying drawing, which is an isometric view of the embodiment.

The apparatus comprises a body 10 having two side members 11 each of which has two arms 12 connected thereto by pivots 13. A flexible, insulated, electric cable 14 is held by clamps 15 on the arms 12 so that two parallel lengths 16 of the cable extend between the arms. Each arm 12 is biassed by a spring 17 so that the clamps holding each length of the cable are urged away from each other to tension the length of cable. Between said lengths 16 of cable, the cable 14 extends in a loop 18 from one end of one length 16 to the opposite end (not visible in the drawing) of the other length 16. The side members 11 are hinged to frame member 19 of the body so that they can be swung towards and away from one another. A hydraulic cylinder 20 carried by the frame member 19 operates a hydraulic ram 21 carrying a housing 22.Arms 23 connect the housing 22 with the side members 11, each arm being pivoted at one end to the housing and at the other end to a side member.

In use, the hydraulic cylinder is, if necessary, operated to give the required spacing apart of the parallel cable lengths. As viewed in the drawing, downwards movement of the hydraulic ram 21 will increase the spacing and upwards movement will decrease the spacing.

The body 10 is moved towards a pipe or intersection to be tested so that the parallel cable lengths engage and then conform to the contour of the pipe or intersection, deflection of the cable lengths being permitted by pivoting of the arms 12. Electric current is passed through the cable to create the necessary magnetic field in the article under test.

Each side member 11 has an arcuate recess 24 between the arms 12, and around one or both recesses are disposed a plurality of fluid dispensing nozzles 25 for supplying magnetic ink to the surface of the article being tested.

The body 10 carries an ultra-violet lamp or lamps 26 to supply ultra-violet light to said surface and a TV camera 27 to observe the surface. It also carries a transformer 28 and heat sink/bus bars and rectifier 29 and has a handle 9'.

The apparatus is particularly intended for use in the testing of articles underwater, e.g.

sub-sea, and for that purpose may be attached to a manipulator arm on a remotely operated vehicle. However, it may be used in other environments.

The device may be disposed on a pipe to be tested so that the lengths of cable extend cross-wise of the pipe, when they will flex to conform to the curved pipe surface. Alternatively the device may be disposed on a pipe to be tested so that the lengths of cable extend along the pipe parallel to its axis.

Instead of a single loop of cable as used in the illustrated embodiment, a plurality of loops of cable may be employed, thus providing more than two parallel lengths of cable for inducing the magnetic field.

Claims

1. Apparatus for use in testing by magnetic particle inspection comprising a body, at least two parallel lengths of flexible, insulated, electric cable, and means connecting said lengths to the body whereby, when the body is moved towards a convex surface of an article to be tested, the lengths both contact the article and deflect to conform with said convex surface.

2. Apparatus according to claim 1 wherein said lengths of cable are different parts of a single cable.

3. Apparatus according to claim 1 or claim 2 wherein said connecting means comprise arms to which said lengths are clamped and which are pivoted on the body.

4. Apparatus according to claim 3 wherein the arms are spring-loaded to apply tension to said lengths.

5. Apparatus according to any preceding claim wherein means are provided for moving said lengths towards and away from each other to adjust the distance between them.

6. Apparatus according to any preceding claim wherein the body preferably carries a plurality of fluid dispensing outlets arranged in an arcuate array so as each to be adjacent to a convex surface of an article to be tested when the lengths of cable conform to said surface.

7. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.