GB2368891A

GB2368891A - Method for inserting a rodded tool into a pipe

Info

Publication number: GB2368891A
Application number: GB0121272A
Authority: GB
Inventors: Timothy John Litt
Original assignee: Lattice Intellectual Property Ltd
Current assignee: Lattice Intellectual Property Ltd
Priority date: 2000-09-05
Filing date: 2001-09-03
Publication date: 2002-05-15
Also published as: GB0021837D0; AU2001282365A1; WO2002021037A1; GB0121272D0

Abstract

A method for inserting a rodded tool into a pipe 1 comprises providing at least a portion of a rod 8 with a tool 7 inside an insertion tube 6 connected to a valve 4 positioned over a hole 2 in a wall of the pipe. A protection tube 10 and a seal 11 are threaded over a portion of the rod so that the seal impedes the flow of fluid from the pipe out of the insertion tube. The valve is opened, and an end of the protection tube is advanced through the hole in the pipe, and at least a portion of the rod connected to the tool is passed through the protection tube into the pipe. Preferably the tool connected to the rod is a camera or detector used for pipeline inspection.

Description

1 236889 1

UNDER PRESSURE INSERTION TOOL

The present invention relates to a method and apparatus for inserting rodded tools or the like into pipes.

Conventionally a fitting as shown in Figure 1 would be used to insert a tool, such as a camera or a detector, into a pipeline for inspection. The pipeline could be used to convey any fluid such as water or fuel gas.

A pipe 1 has a tapped hole 2 drilled therein using well known techniques for drilling holes into pipes that are under pressure. A seal 3 and a valve arrangement 4 are secured over the drilled hole 2 using restraining straps 5 to prevent the loss of fluid from the pipe 1. An insertion tube 6 is attached to the valve arrangement 4 and a probe 7 mounted on an insertion rod 8 is inserted into the tube 6. A labyrinth seal 9 is then attached to the insertion tube 6 permitting the push rod 8 to pass therethrough and the valve arrangement 4 is opened to permit the probe 7 to be inserted through the hole 2 into pipe 1. The insertion tube 6 could be vertical or at an angle as shown in dashed lines to assist insertion in a particular direction of the pipe 1 or moveable between the two.

A problem with the fitting shown in Figure 1 is that as the rodded probe 7 is inserted into and along pipe 1 the push rod 8 can scrape against the edge of hole 2 damaging the push rod 8. A profiled insert 9 shown by dashed lines in Figure 1 may be used to line hole 2 to protect the rod during insertion.

However, this reduces the diameter of the hole 2 making the insertion of a probe more difficult.

According to a first aspect of the present invention there is provided a method for inserting a rodded tool or the like into a pipe carrying fluid, the method comprising threading a protection tube and a seal over a portion of the push rod such that the seal impedes the flow of fluid from the pipe out of the insertion tube; opening the valve; advancing the end of the protection tube closest to the pipe through the hole in the pipe and passing at least a portion of the rod connected to the tool through the protection tube into the pipe. According to a second aspect of the present invention there is provided an apparatus for inserting a rodded tool or the like into a pipe carrying fluid with a hole in its wall, a valve positioned over the hole and an insertion tube connected to the valve; the apparatus comprising a protection

tube arranged to be threaded over a rod and positioned with at least a portion of the rod within the insertion tube, a seal arranged to be threaded over the rod to impede the flow of fluid from the pipe out of the insertion tube and wherein an end portion of the protection tube is arranged to be inserted through the hole in the pipe when the valve is open.

In use the protection tube is slid through tapped hole 2 to protect a rod attached to a probe from scraping against the edge of the tapped hole 2 as it is passed into the pipe.

An example of the invention will now be described with reference to figure 2.

Like the conventional method described earlier, a hole 2 is drilled into a pipe 1 and valve arrangement 4 is provided to prevent the loss of fluid from pipe 1. An insertion tube 6 is attached to the valve arrangement 4. A probe 7 with push rod 8 is inserted into insertion tube 6. The push rod 8 has protection tube 10 and an associated seal 11 arranged substantially concentrically around it also in insertion tube 6. The protection tube 10 and associated seal 11 may be threaded over push rod 8 from its free end.

The seal 11 comprises a labyrinth seal 12 provided in a housing 13. The labyrinth seal 12 reduces the amount of

fluid passing from pipe 1 through the inside of the housing 13 to the outside air. The seal 11 is also provided with, in this example, two O rings 14 arranged circumferentially around the housing to reduce the amount of fluid passing from pipe 1 between the outside of the housing 13 and the inside of the insertion tube 6 to beyond the seal 11. The O rings enable the seal 11 and protection tube 10 to slide within insertion tube 6. In use, as the push rod 8 is inserted further into pipe 1 or withdrawn from pipe 1, it will pass through labyrinth seal 12 with only a negligible amount of fluid escaping from pipe 1.

If desired an additional fixed labyrinth seal 9 can be positioned at the top of insertion tube 6.

Valve arrangement 4 is opened and protection tube 10 and associated seal 11 are then advanced such that a front end of protection tube 10 enters pipe 1 and extends beyond hole 2.

Probe push rod 8 can then be advanced into pipe 1 without scraping against the edge of hole 2 because of the protection provided by protection tube 10. Protection tube 10 and associated seal 11 are advanced to the position shown in Figure 2 by manipulation of a positioning rod 15 from the end of insertion tube 6. Positioning rod 15 may be secured against insertion tube 6 to keep protection tube 10 and associated seal 11 in position despite the friction from the

advance and retraction of rod 8 to ensure that protection tube 10 continues to be in a suitable position to protect the push rod 8 from scraping against the edge of the hole 2.

When it is desired to remove probe 7 from the pipe 1, the probe push rod 8 is withdrawn from the top of insertion tube 6. The protection tube 10 prevents the probe push rod 8 from scraping against hole 2 during withdrawal in a similar manner to insertion. When the probe 7 has been withdrawn as far as protection tube lo, positioning rod 15 is released from its fixed position against insertion tube 6 and the probe 7 and protection tube 10 are then withdrawn out past hole 2 and valve arrangement 4 into insertion tube 6. Valve arrangement 4 is then closed to prevent the release of gas and the probe 7, push rod 8, protection tube 10, seal 11 and positioning rod 15 are removed from the insertion tube 6.

If no further probes need to be inserted into pipe 1 the hole 2 may be permanently sealed with a plug for example.

Many alterations may be made to the example described above whilst still falling within the scope of the invention. For example, instead of a push rod 8, the invention may be used with any suitable flexible elongate member such as a cable.

The protection tube 10 and associated seal 11 may be fixed into the position such that they prevent scraping of the push

rod against the edge of the hole 2 by any suitable means or may be held in position by friction.

Claims

1. A method for inserting a rodded tool or the like into a pipe, the method comprising providing at least a postion of a rod with a tool on an end portion of the rod inside an insertion tube connected to a valve positioned over a hole in the wall of a pipe; threading a protection tube and a seal over a portion of the rod such that the seal impedes the flow of fluid from the pipe out of the insertion tube; opening the valve; advancing the end of the protection tube closest to the pipe through the hole in the pipe and passing at least a portion of the rod connected to the tool through the protection tube into the pipe.

2. A method according to claim 1, wherein the protection tube is secured in its advanced position.

3. A method according to claim 1 or claim 2, wherein the protection tube is advanced using a positioning rod connected to the protection tube.

4. A method according to claim 3, wherein the protection tube is secured in its advanced position by securing the positioning rod to the insertion tube.

5. A method according to any of the preceding claims, whrein the seal is advanced along the protection tube.

6. A method according to claim 5, wherein the insertion tube and the seal are connected together.

7. A method for inserting a rodded tool or the like into a pipe substantially as hereinbefore described with reference to the accompanying drawings.

8. An apparatus for inserting a rodded tool or the like into a pipe with a hole in its wall, a valve positioned over the hole and an insertion tube connected to the valve, the apparatus comprising, a protection tube arranged to be threaded over a rod and positioned with a portion of the rod within the insertion tube, a seal arranged to be threaded over the rod to impede the flow of fluid from the pipe out of the insertion tube and wherein an end portion of the protection tube is arranged to be inserted through the hole in the pipe when the valve is open.

9. An apparatus according to claim 8, wherein the protection tube is provided with a positioning rod to advance an end portion of it into the pipe.

10. An apparatus according to claim 9, wherein the protection tube is provided with locking means to lock it in its advanced position.

11. An apparatus according to any of claims 8 to 10, wherein the protection tube and seal are secured together.

12. An apparatus substantially as hereinbefore described with reference to the accompanying drawings.