GB2244333A

GB2244333A - Depth gauge

Info

Publication number: GB2244333A
Application number: GB9010746A
Authority: GB
Inventors: Mahir Moss Mustafa
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-05-14
Filing date: 1990-05-14
Publication date: 1991-11-27
Anticipated expiration: 2010-05-14
Also published as: GB9010746D0; GB2244333B

Abstract

A gauge 1 for measuring the depth or width of a crack, eg in a weld, in a substrate comprising a body 4 providing a datum 5 for resting on the substrate adjacent a crack 2, an angular measure 6, which is on the body 4 and a probe 7 mounted on the body 4 by mounting means 8, the arrangement being such that the probe 7 can be extended on the mounting means 8 relative to the body 4 at an angular displacement measured by the angular measure 6 whereby to provide a reading in use of the depth or width of a crack. <IMAGE>

Description

A DEPTH GAUGE The invention relates to a depth gauge for measuring the depth or width of a crack in a surface.

It is often necessary and desirable to monitor corrosion of articles such as support structures used sub-sea. This is particularly so on oil rigs where safety considerations require that cracks in structures, particularly at or adjacent welds, are monitored as to their depth. To do this it is usually necessary to carry out inspection below the surface of a hostile environment, the North Sea, say, where the employment of cumbersome equipment can be difficult, and dangerous and which in any event cannot provide an accurate measurement.

It is accordingly an object of the invention to seek to provide a gauge which can readily measure a dimension of a crack in a surface.

According to the invention there is provided a gauge for measuring the depth or width of a crack in a surface, comprising a body providing a datum for resting on the surface adjacent a crack, an angular measure and a probe mounted on the body by mounting means, the arrangement being such that the probe can be extended on the mounting means relative to the body at an angular displacement measured by the angular measure whereby to provide a reading in use of the depth or width of a crack.

The body may comprise a plate and the datum may comprise a minor surface of the body.

The mounting means may comprise a linear slide device rotatable with respect to the body.

The linear slide device may comprise a rail mounted for rotation with respect to the body and a slide part of the probe mounted on the rail.

The probe may comprise an elongate member slidable with respect to the slide part.

The slide part may include a graduated scale and the probe may have reference means for indicating a point on the scale.

The reference means may comprise a pointer projecting laterally from the probe.

There may be means to secure the probe in a desired angular and extended position.

The body may comprise a metal plate.

There may be means to secure the gauge in a desired position preferably comprising a hole through the body.

A gauge embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawings.

Fig 1 is a side elevational view of a gauge, particularly a depth gauge, according to the invention and for use in measuring the depth of a crack in a sub-sea structure; Fig 2 is a plan view of the gauge of Fig 1; Fig 3 shows schematically a structure and the gauge of Figs 1 and 2 in use; and Fig 4 shows a side elevational view of another embodiment of gauge according to the invention.

Referring to the drawings in which like parts are referred to by like numerals, there is shown a gauge 1 for measuring the depth or width of a crack 2 (Fig 3) in a substrate 3, comprising a body 4 providing a datum 5 for resting on the substrate 3 adjacent a crack 2, an angular measure 6, which is on the body 4 and a probe 7 mounted on the body 4 by mounting means 8, the arrangement being such that the probe 7 can be extended on the mounting means 8 relative to the body 4 at an angular displacement measured by the angular measure 6 whereby to provide a reading in use of the depth or width of a crack 2.

The body 4 comprises a flat plate suitably of metal and is generally of L-shape the foot of one limb 9 of the "L" providing a ground flat surface which is the datum 5.

There is a hole 10 through the plate in the other limb 11 of the "L" through which passes a threaded rod 12 with a knurled nut 13 on the rear (as viewed) side of the plate 4, the nut 13 supporting adjacent the front side a dove-tail section slide or rail 14 on which is mounted a slide part 15 of the probe 7 which slide part 15 has a dove-tail configuration complementary to that of the rail 14.

The rail 14 and slide part 16 form a linear slide device of the gauge 1.

The slide part 15 is part of a body which is also of L-shape (Fig 2), the slide part 15 being in one limb 16, the other 17 of which mounts the probe 7 which is slidable up and down in a slide way 18 of the other part 17, the probe 7 having reference means in the form of pointer or pin 19 projecting from the probe through a groove 20 in the other part 17 of the L-shape slide part body 15.

The probe 7 can be secured in position by a bolt 21 having a manually operable knurled knob 22.

The surface of the part 16 has a graduated scale 23, for example in millimetres. The angular measure 6 comprises a 900 sector, the 900 line being aligned with a flat edge 24 of the slide part body.

The gauge 1 includes securing means in the form of a hole 25 through which a lanyard can be secured to attach the gauge 1 to a diver.

The gauge 1 may be used to measure the depth of a crack 2 at a weld 26 in a sub-sea structure such as adjacent the (welded) connection between a platform member 3 and a platform leg 27.

In use, the datum 5 is placed on the structure or substrate 3 adjacend the weld 26, and, with the knurled nuts 13, 22 loosened, the tip of the probe 7 (which is tapered) is lined up with the edge "Z" of the crack by the diver. The probe 7 is adjusted longitudinally so that the pointer 19 is on the zero on the graduated scale 23 and the nut 22 is tightened. The edge 24 is on the 900 mark on the angular scale 6.

The mounting means 8 is then rotated about rod 12 and the slide part 8 extended so that the probe 7 moves down to engage the bottom of the crack 2, and the knob 13 is tightened. The edge 24 then lies over a certain angle on the scale 6, and the pointer 19 against a depth mark on the scale 23. The diver notes these readings, or transmits them to the surface to a control using suitable means such as radio. Knowing the depth and the angle of the crack (grinding under the weld) vertical penetration "X" into the parent metal can be calculated by trigonometrical means.

Claims

1. A gauge for measuring the depth or width of a crack in a surface, comprising a body providing a datum for resting on the surface adjacent a crack, an angular measure carried by the body, and a probe mounted on the body by mounting means, the arrangement being such that the probe can be extended on the mounting means relative to the body at an angular displacement measured by the angular measure whereby to provide a reading in use of the depth or width of a crack.

2. A gauge according to Claim 1, the body comprising a plate and the datum comprising a minor surface of the body.

3. A gauge according to Claim 1 or Claim 2, the mounting means comprising a linear slide device rotatable with respect ot the body.

4. A gauge according to Claim 3, the linear slide device comprising a rail mounted for rotation with respect to the body and a slide part of the probe mounted on the rail.

5. A gauge according to Claim 4, the probe comprising an elongate member slidable with respect to the slide part.

6. A gauge according to Claim 5, the slide part including a graduated scale and the probe having reference means for indicating a point on the scale.

7. A gauge according to Claim 6, the reference means comprising a pointer projecting laterally from the probe.

8. A gauge according to Claim 7, including means to secure the probe in a desired angular and extended position.

9. A gauge according to Claim 8, the body comprising a metal plate.

10. A gauge according to any preceding Claim, including means to secure the gauge in a desired position.

11. A gauge according to Claim 10, the securing means comprising a hole through the body.

12. A gauge for measuring the depth or width of a crack in a surface, substantially as hereinbefore described with reference to the accompanying drawings.