GB2469286A

GB2469286A - Internal inspection apparatus for pipes

Info

Publication number: GB2469286A
Application number: GB0906000A
Authority: GB
Inventors: Brian Beech; Jason Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-04-07
Filing date: 2009-04-07
Publication date: 2010-10-13
Also published as: GB0906000D0

Abstract

An internal inspection apparatus is provided for pipes. The apparatus comprises a device 3 clamped to a pipe 1 to be inspected. The device has an entry tube 7 for an inspection assembly. The entry tube is provided with a valve (9) e.g. a gate valve which, when opened, leaves the entry tube unobstructed. The entry tube 7 extends at an acute included angle e.g. thirty degrees relative to the axis of the pipe 1. The clamp attaching the device to the pipe may be a pair of semi-cylindrical sleeve members e.g. member 5. Inspection means may be visual e.g, a camera 27 or audio e.g. a microphone. A cutter assembly (13) may initially be attached to the entry tube 7 to cut through the wall of the pipe prior to inspection.

Description

INTERNAL INSPECTION APPARATUS FOR PIPES

This invention relates to an internal inspection apparatus for pipes.

It is known to provide internal inspection of pressurised pipes, for example water or gas pipes, by inserting a camera or other inspection device through a wall of the pipe substantially at right angles to the axis of the pipe. While this provides the ability to provide local inspection, it has been found that a camera cable, for example, does not readily bend through 90 degrees to allow inspection at a location remote from the camera entry location. For example, it has been found that the edges of the aperture for camera entry cause costly damage to the cable.

It is therefore an object of the present invention to provide an internal inspection apparatus for pipes which overcomes, or at least ameliorates, the problems associated with known apparatus.

According to the present invention there is provided an internal inspection apparatus for pipes comprising a valve clamped to a pipe to be inspected, the valve being provided with an entry tube for an inspection assembly, the entry tube being provided with valve means which, when opened, leaves the entry tube unobstructed, the entry tube extending at an acute included angle relative to the axis of the pipe.

The valve means may comprise a gate valve.

The clamping means may comprise two substantially semi-cylindrical sleeve members, one of which carries the entry tube.

The entry tube may extend at an angle of substantially 30 degrees to the axis of the pipe.

A flange may be provided at an outer end of the entry tube for securing an inspection assembly thereto.

The inspection assembly may comprise inspection means provided at one end of a flexible cable, the inspection assembly being attached to the entry tube in a substantially fluid-tight manner.

Attachment means for the inspection means may comprise a guide tube which passes into the entry tube in a slidable manner to allow axial movement of the guide tube relative to the entry tube, the cable passing through the guide tube.

The guide tube may be provided with a handle for moving the guide tube in the axial direction.

The attachment means may include locking means for locking the guide tube in a position in which it has been moved into the entry tube.

The attachment means may comprise a guide member provided within the entry tube and attached to and movable with an end of the guide tube.

The inspection means and the guide member may be provided with co-operating surfaces, for example part-conical surfaces, whereby the guide member can guide the inspection means in the axial direction of the entry tube.

The guide member may be provided with a surface to guide the cable into the pipe without contacting an edge of a hole formed in a wall of the pipe to allow passage of the inspection means and cable into the pipe. The guide surface may be part of the co-operating surface of the guide member.

The diameter of the guide member may be such that it closely fits within the entry tube to ensure the guide member moves in the axial direction of the entry tube.

The inspection means may comprise visual inspection means, such as a camera, or audio inspection means, such as a microphone.

The inspection apparatus may include means for cutting a hole in a wall of the pipe to allow access to the interior of the pipe, the hole cutting means being attached to the entry tube in a substantially fluid-tight manner.

The hole cutting means may comprise a hole cutter attached to a drive shaft, the hole cutter being mounted within the entry tube and the drive shaft passing out of the entry tube.

The hole cutter may have a length of at least 2.5 times the diameter of the hole to be cut.

The diameter of the hole cutter may be such that it closely fits within the entry tube to resist deflection when in operation.

A magnet may be provided within the hole cutter to retain the pipe wall section removed during cutting.

For a better understanding of the present invention and to show more clearly how it may be carried into effect reference will now be made, by way of example, to the accompanying drawings in which: Figure 1 is a cross-sectional view of part of an apparatus according to the present invention in a first configuration for internal inspection of pipes; Figure 2 is a cross-sectional view of the apparatus shown in Figure 1 in a second configuration; Figure 3 is a perspective view of the apparatus shown in Figures 1 and 2; Figure 4 is a cross-sectional view of a further part of an apparatus according to the present invention in a first configuration for internal inspection of pipes; Figure 5 is a cross-sectional view of the apparatus of Figure 4 in a second configuration; and Figure 6 is a perspective view of the apparatus shown in Figures 4 and 5.

The apparatus shown in Figures 1 to 3 is employed in a first step of forming a hole in a pipe 1 which is to be inspected. A valve 3 is clamped to the pipe 1 by means of two substantially semi-cylindrical sleeve members 5, only one of which is shown in the figures. The two sleeve members 5 are each formed with axially-extending flanges which are fastened together with suitable fasteners (not shown). The upper sleeve member 5 is provided with an entry tube 7 which extends at an acute included angle relative to the axis of the pipe 1, the entry tube being provided with valve means in the form of a gate valve plate 9 for closing and opening the valve 3, the valve plate 9 leaving the interior of the entry tube unobstructed when opened. The entry tube may be at an angle of, for example, substantially 30 degrees relative to the axis of the pipe 1. An outer end of the entry tube 7 is provided with a flange 11, for example internally threaded, for securing operative components to the valve 3 as will be explained in more detail hereinafter.

The pipe 1 is exposed at a point upstream of a leak, for example by way of an inspection cover to which a valve 3 has previously been fitted and access to the pipe 1 has been provided or by digging a hole and attaching a valve to the pipe.

Where a valve 3 has to be attached to the pipe 1 it is also necessary to cut a hole through the wall of the pipe. This is accomplished by attaching a cutter assembly 13 to the end of the entry tube 7 in a fluid-tight manner (such as by way of the internal thread in the entry tube). The cutter assembly comprises a hole cutter 15 attached to a drive shaft 17, the hole cutter being mounted within the entry tube 7 and the drive shaft passing through a support bearing in the region of the end of the entry tube. The hole cutter ideally has an axial length at least 2.5 times the diameter of the hole to be cut. In addition, the hole cutter ideally has a diameter such as to provide a minimal clearance within the entry tube so as to resist deflection when cutting of the hole is started. A magnet (not shown), such as a flexibly mounted conical magnet, is provided within the hole cutter 15 and attached to the wall of the pipe so as to retain the elliptical wall section within the hole cutter and prevent it falling into the pipe 1.

Externally of the entry tube 7 the drive shaft 17 passes through an hydraulic tube 19 which is provided with a seal at the free end thereof. The hydraulic tube 19 is provided with a number, three as illustrated, of external support rods 23 which extend the length of the hydraulic tube and are secured at each end thereof.

Within the hydraulic tube 19, the drive shaft is formed with a radial flange 21 which engages with the internal surface of the hydraulic tube 19 to act as a piston. Hydraulic ports are provided at the free end of the hydraulic tube 19 and in the mounting of the cutter to the free end of the entry tube 7.

In order to cut a hole in the wall of the pipe 1, after the cutter assembly 13 has been attached to the entry tube 7, the valve plate 9 is withdrawn to provide access to the pipe wall. When cutting the hole in the wall of the pipe 1, the relationship between the diameter of the drive shaft 17 and the internal diameter of the hydraulic tube 19 is such that, when the hole cutter 15 breaks into the pipe 1 the outward pressure urging the hole cutter 15 away from the pipe is balanced by hydraulic pressure urging the hole cutter towards the pipe. The balanced forces allow damped freedom of movement of the hole cutter 15 towards and away from the pipe, which is helpful when drilling. Alternatively, a rack and pinion arrangement can be used, but is considerably heavier.

Once the hole has been cut in the wall of the pipe, the hole cutter 15 can be withdrawn together with the separated wall portion, the valve plate 9 can be closed and the cutter assembly 13 can be removed from the entry tube 7. In the event it has been necessary to dig a hole to expose the pipe 1 and attach the valve 3, the hole can either be filled, or more preferably, the sides of the hole can be bricked or the like and an inspection cover provided to allow subsequent access to the valve if needed.

The apparatus shown in Figures 4 to 6 is employed in a second step during which the pipe 1 is inspected internally. A camera assembly 25 is attached to the end of the entry tube 7 in a fluid-tight manner (such as by way of the internal thread in the entry tube). The camera assembly comprises a video camera 27 which incorporates a housing having a part-conical surface at that end thereof remote from the pipe. The camera 27 is connected to a cable which comprises a first portion 29 in the region of the camera and a second portion 31 remote from the camera. The cable comprises electrical cabling within a flexible hose for the first portion 29 and within a nylon covered glass fibre tube for the second portion 31, the first portion 29 of the cable being more flexible than the second portion 31 to facilitate entry into the pipe 1. However, in practice it has been found that the edge of the hole formed in the wall of the pipe causes damage to the glass fibre tube, even when the glass fibre tube is inserted at an acute angle relative to the axis of the pipe, although damage is reduced in such a case.

Indeed, it has been found that an angle of 30 degrees relative to the axis of the pipe 1 provides the best compromise between ease of forming the hole in the wall of the pipe 1 and the flexibility of the cable.

Damage to the glass fibre tube can be substantially eliminated with a guide assembly for the camera 27 and cable portions 29, 31. The guide assembly comprises a guide tube 33 which surrounds the cable portion 31 within the entry tube 7. The guide tube 33 is slidable within the camera assembly 25 and can move into and out of the entry tube. The free end of the guide tube 33 is provided with a handle 35 for moving the guide tube relative to the entry tube, the handle being provided with locking means 37 which is engageable with that part of the camera assembly which engages with the end of the entry tube 7 for releasably locking the handle 35 to the end of the entry tube. The end of the guide tube within the entry tube is provided with a camera guide member 39.

The external diameter of the camera guide member provides minimal clearance with the internal surface of the entry tube 7 so as to ensure the camera guide member 39 moves in the axial direction of the entry tube as a result of movement of the handle 35 and guide tube 33. The free end of the camera guide member 39 is provided with a part-conical internal surface complementary to the end surface of the camera 27 so as to receive the same during inward and outward movement of the handle 35, guide tube 33 and guide member 39. The internal end of the part-conical surface of the guide member 39 is formed with a blended radius to minimise friction with the cable and to avoid sharp edges and eliminate damage to the cable in this region. If required, the internal surface of the free end of the camera guide member 39 can be polished to further reduce the possibility of damage to the cable.

As an alternative to a camera, other pipe inspection means, such as a microphone, can be employed. A microphone can be used to detect the flow of fluid through a leak acoustically.

In use of the camera ssembJy 25, the camera assembly is attached to the end of the entry tube 7 with the camera 27 and camera guide member 39 retracted to a rearward position. Once securely attached, the valve plate 9 is withdrawn and the handle 35 is used to move the camera 27 and camera guide member 39 to a forward position within the valve 3 and is locked in this position. In the forward position, the free end of the camera guide member 39 projects a short distance into the pipe 1 with part of the guide member protruding into the pipe and part substantially corresponding to the wall of the pipe (the most forward part of the guide member). In this way, the camera 27 can be moved into the pipe 1 without contacting the wall of the pipe and therefore without causing any significant damage to the cable. The camera cable passes through the guide tube 33 and camera guide member 39 to allow the camera 25 to move relative to the pipe 1 for the purpose of inspecting the pipe internally so as to identify any leaks.

The camera 25 is removed from the pipe 1 by retracting the cable so as to draw the camera into the guide member 39 with the part-conical surface at the end thereof fitting within the part-conical surface of the guide member. The handle is then unlocked and moved to a retracted position. The valve plate 9 is then closed and the camera assembly 25 is removed from the end of the entry tube 7.

Claims

CLAIMS1. An internal inspection apparatus for pipes comprising a valve clamped to a pipe to be inspected, the valve being provided with an entry tube for an inspection assembly, the entry tube being provided with valve means which, when opened, leaves the entry tube unobstructed, the entry tube extending at an acute included angle relative to the axis of the pipe.
2. An apparatus as claimed in claim 1, wherein the valve means comprises agate valve.

(Y)
3. An apparatus as claimed in claim 1 or 2, wherein the clamping means comprises two substantially semi-cylindrical sleeve members, one of which (0 carries the entry tube.
4. An apparatus as claimed in claim 1, 2 or 3, wherein the entry tube extends at an angle of substantially 30 degrees to the axis of the pipe.
5. An apparatus as claimed in any preceding claim, wherein the flange is provided at an outer end of the entry tube for securing an inspection assembly thereto.
6. An apparatus as claimed in claim 5, wherein the inspection assembly comprises inspection means provided at one end of a flexible cable, the inspection assembly being attached to the entry tube in a substantially fluid-tight manner.
7. An apparatus as claimed in claim 6, wherein attachment means for the inspection means comprises a guide tube which passes into the entry tube in a slidable manner to allow axial movement of the guide tube relative to the entry tube, the cable passing through the guide tube.
8. An apparatus as claimed in claim 7, wherein the guide tube is provided with a handle for moving the guide tube in the axial direction.

(Y)
9. An apparatus as claimed in claim 7 or 8, wherein the attachment means includes locking means for locking the guide tube in a position in which it has been moved into the entry tube.
10. An apparatus as claimed in claim 7, 8 or 9, wherein the attachment means comprises a guide member provided within the entry tube and attached to and movable with an end of the guide tube.
11. An apparatus as claimed in claim 10, wherein the inspection means and the guide member are provided with co-operating surfaces, whereby the guide member can guide the inspection means in the axial direction of the entry tube.
12. An apparatus as claimed in claim 11, wherein the co-operating surfaces are part-conical surfaces.
13. An apparatus as claimed in claim 10, 11 or 12, wherein the guide member is provided with a surface to guide the cable into the pipe without contacting an edge of a hole formed in a wall of the pipe to allow passage of the inspection means and cable into the pipe.
14. An apparatus as claimed in claim 13, wherein the guide surface is part of the co-operating surface of the guide member.

(Y)
15. An apparatus as claimed in any one of claims 10 to 14, wherein the diameter of the guide member is such that it closely fits within the entry tube to (0 ensure the guide member moves in the axial direction of the entry tube.
16. An apparatus as claimed in any preceding claim, wherein the inspection means comprises visual inspection means.
17. An apparatus as claimed in claim 16, wherein the visual inspection means comprises a camera.
18. An apparatus as claimed in any one of claims 1 to 15, wherein the inspection means comprises audio inspection means. -14-
19. An apparatus as claimed in claim 18, wherein the audio inspection means comprises a microphone.
20. An apparatus as claimed in any preceding claim, wherein the inspection apparatus includes means for cutting a hole in a wall of the pipe to allow access to the interior of the pipe, the hole cutting means being attached to the entry tube in a substantially fluid-tight manner.
21. An apparatus as claimed in claim 20, wherein the hole cutting means comprises a hole cutter attached to a drive shaft, the hole cutter being mounted within the entry tube and the drive shaft passing out of the entry tube. C)
22. An apparatus as claimed in claim 21, wherein the hole cutter has a length (0 of at least 2.5 times the diameter of the hole to be cut.
23. An apparatus as claimed in claim 21 or 22, wherein the diameter of the hole cutter is such that it closely fits within the entry tube to resist deflection when in operation.
24. An apparatus as claimed in claim 21, 22 or 23, wherein a magnet is provided within the hole cutter to retain the pipe wall section removed during cutting.
25. An internal inspection apparatus for pipes substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings. C) (0