AU2004200360A1 - Method and apparatus for isolation of pipeline - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLETED BY APPLICANT Name of Applicant: Actual Inventor(s): Address for Service: Invention Title: PTC GROUP PTY LTD Philip Thompson; Frank Dyer CALLINAN LAWRIE, 711 High Street, Kew, Victoria 3101, Australia METHOD AND APPARATUS FOR ISOLATION OF

PIPELINE

The following statement is a full description of this invention, including the best method of performing it known to us:- 30/01/04jfgf4757 spc,2 The present invention relates, in general terms, to a method and apparatus for use in the maintenance of a supply of fluid or liquid through a conduit therefor, as for example a pipeline. More particularly, but not exclusively, the invention relates to a method and apparatus which allows for ready isolation of a given or predetermined section of such conduit, for purposes of repair and maintenance, connection of a branch conduit, or any other purpose/treatment.

Throughout the ensuing description reference will be made to an especially preferred usage for the method and apparatus in accordance with the present invention, namely for purposes of maintenance of water piping, including for example town water supply mains piping. It should be understood, however, that the method and apparatus in accordance with the present invention are not to be considered to be restricted solely to such a preferred usage. In actual fact the invention is equally suited to use in any situation wherein a supply of liquid or fluid, be it water, oil or gas for that matter, is being directed through a given conduit therefor, and wherein for whatever reason it becomes necessary to interrupt, albeit temporarily, such supply.

All structures nowadays, and some more than others, require access to a supply of water, for example mains or town water. Such is regardless of whether or not such structure is employed for domestic or commercial purposes. In a domestic sense, the consequences of an unwanted and lengthy interruption to supply of mains water can be significant in terms of discomfiture to the householder and occupants. In a commercial sense, the consequences of unwanted and lengthy interruption to supply can be even more serious, in terms of disruption to business, loss of output, loss of income, etc.

There can exist a number of different circumstances wherein disruption of supply of mains water takes place, either intentionally or unintentionally or accidentally. By way of example, in the instance of a breakage occurring in the mains water, piping, the supply of water through such piping has to be interrupted to allow for, firstly, the location of the break and, ultimately, the repair thereof. In another example it can become necessary to connect a new property/household/structure to an existing mains pipeline. In either or both of these situations it is clearly in the best interests of all users of the supply of fluid or water that any disruption to supply is minimised, in terms of duration and water conservation. These days, in particular, with many parts of the continent experiencing 30/01/04jfgf4757 spc.2 -3draught conditions, it would be totally unacceptable and wasteful to have a broken or damaged pipeline leaking gushing large volumes of water for any significant period.

The situation often arises these days, in the building industry for example, wherein it becomes necessary during erection of a new structure to arrange for connection thereof to a mains supply of water. The situation also arises wherein there can be a need for repair, maintenance or replacement of a given section of piping or ducting used for water supply purposes, as for example in the instance of breakage or damage thereto.

Known and presently in use procedures and apparatus for carrying out repair, maintenance and reconnection by their very nature generally necessitate interruption of supply of the relevant fluid for a considerable period of time, in effect the entire period of time when the necessary work is being carried out. Such interruption can be extremely undesirable, since in effect all potential or actual customers or users downstream of the site where the work is being carried out may also be inconvenienced.

In accordance with known practices mains piping generally involves a branching network disposed underground and running down and along suburban streets and past households, commercial structures, etc., with each individual user being connected to the nearest mains pipeline by a suitable branch conduit. At street level, mains water pipelines are usually provided with closure means, in the form of gates, valves or the like, disposed at regular intervals therealong, as for example at street corners, etc. Such closure means allow sections of pipeline to be isolated as and where necessary, as for example to allow for maintenance thereof or to allow for a new connection to be made thereto. Such closure means as presently employed for purposes of isolation, however, are by their very nature not property specific, in fact allowing only for selected isolation of perhaps a substantial number of different users/sites at any one time. By reason of that fact, then in a situation wherein considerable maintenance is required, there can be expected to be disruption to supply, perhaps for an inordinate length of time, to a number of different households or commercial premises. This can give rise, in turn, to all sorts of consequences in terms of discomfiture for users, and perhaps even in terms of the overall health of such users.

In that regard it should be realised that, nowadays, it is the common practice to have watermains in the form of a metal conduit/pipeline of a given outer diameter (and 30/01/04jfgf4757 spc,3 inner diameter), with a sleeve or coating of a suitable cementitious material associated therewith, disposed therein and affixed thereto. By virtue of the very nature of such cementitious material, there can be significant differences in the effective internal diameter of the overall pipeline at different locations therealong. Furthermore, the thickness of the cementitious material has been found to vary significantly around the circumference of the pipeline itself. By virtue of this variation an internal diameter, in accordance with known practices there have always existed problems in ensuring adequate "plugging" or sealing of such a pipeline. There was no guarantee that any plug used would achieve or give rise to leak-proof sealing. Various means have been employed in attempts to solve this problem, with differing degrees of success, such means more often than not involving relatively complicated pieces of equipment. The present invention addresses this problem of ensuring leak-proof plugging or sealing, at any point on a given pipeline, in a simple manner and using standardised means.

The present invention seeks to overcome the problems and disadvantages associated with the prior art by providing a method and apparatus which allows for the formation, at a given site in a given section of piping, of a temporary plug, whilst the main itself remains under pressure. In the result, all those customers/users on the upstream side of the site of operation will enjoy substantially uninterrupted supply, even during that time when repair, maintenance or connection is being effected.

In accordance with the invention, in any situation where work needs to be carried out at a predetermined location on a pipeline, two pieces of apparatus can be appropriately located on the pipeline, one on each side of the proposed site of operation, whereby to temporarily, at least, interrupt supply and allow for isolation of the section of pipeline thus defined. In accordance with known practices temporary means of any known type may be employed whereby to restore supply at the earliest possible time, even before the necessary work has been begun, let alone completed.

Such represents a significant advance over known practices. Here in Australia, for example, it is the general practice that, in any situation wherein supply of water is to be interrupted, it is a requirement to give those consumers likely to be in any way effected thereby adequate warning thereof, whereby to allow them to take appropriate precautions/alternative measures.

30/01/04jfgf4757 spc,4 In one aspect, therefore, the present invention relates to a method for allowing a section of a pipeline for carrying or supplying fluid (liquid such as water or a gas) to be isolated, the method including the installation of a temporary plug in the pipeline while that pipeline is under pressure, yet still enabling repair and/or maintenance work to be effected without lengthy interruption of supply, said method further including: drilling/tapping a hole in said pipeline of a predetermined size; forming a groove or seating around the internal diameter of said tapped pipeline; and locating a plug or the like flow interruption means through said tapped hole into said pipeline, the outer periphery of said plug or the like flow interruption means being adapted to be located within said formed groove/seating.

In accordance with a further aspect there is provided a plug or flow interruption means for use in the aforementioned method, said plug preferably being constructed from a substantially rigid material, such as rubber, and having a metal pin or the like extending substantially centrally thereof, whereby to afford increased rigidity and prevent said plug exiting said groove/seating when under pressure.

The invention also provides an apparatus for the under-pressure sealing of a pipeline, said apparatus including: means adapted to be removably associated with said pipeline whereby to define a location for sealing and having a valve means associated therewith; means for under-pressure tapping of said pipeline; and plug means adapted to be disposed within said pipeline whereby to seal said pipeline against flow downstream of said location means, wherein said plug means is in the form of a substantially rigid member adapted, in use, to occupy the entire cross-section of said pipeline, whereby to provide a sealing effect for said pipeline.

The invention further provides a method for the under-pressure sealing of a pipeline, said method including the steps of: locating a means for tapping said pipeline at a predetermined position thereon, said means for tapping having valve means associated therewith; tapping said pipeline at said predetermined position thereon; removing said means for tapping, whilst said valve means is closed; forming a groove or seating about at least a major part of the internal diameter/ periphery of said pipeline; locating a plug or the 30101/04jfgf4757 like means within said pipeline, said plug being adapted, in use, to have its outer periphery disposed within said groove or seating formed within said pipeline.

In accordance with a further aspect of the invention there is provided a plug or flow interruption means for use in aforementioned method, said plug preferably being constructed from a substantially rigid material, such as rubber, and having a metal pin or the like extending substantially centrally thereof, whereby to afford increased rigidity and prevent said plug exiting said groove/seating when under pressure.

In order that the invention may be more clearly understood and put into practical effect reference will now be made to a preferred method and apparatus in accordance with the invention. The ensuing description is given by way of non-limitative example only and is with reference to the accompanying drawings, wherein: FIG. 1 is a sectional view of an apparatus employed for carrying out a tapping and isolating procedure for a pipeline, in accordance with the invention; FIG. 2 is an exploded view of a first embodiment of a plug means in accordance with the present invention, located within a pipeline but not yet properly seated therein; FIG. 3 is a view, similar to FIG. 2 but with the plug thereof properly and sealingly disposed within a seating formed in the lining of a pipeline; FIG 4, is a cross-sectional view of a pipeline, showing the formation of a seating, in accordance with the method of the invention, in the internal lining (cementitious) material thereof; and FIG. 5 is a perspective view, from above, of an alternative embodiment of a plug means in accordance with the present invention.

With reference now to the drawings, there will be described in more detail the method in accordance with the present invention, and the apparatus employed for carrying out such a method. Consider, by way of example only, the situation wherein a new user is to be connected.

In a first step in the method a flanged off-take or tapping band, comprised of individual and complementary components 1 A and 1IB and a suitable sealing means 2 of any known type, is adapted to be appropriately positioned, at a desired location, on the 30/01/04jfgf4757 spc,6 -7watermain or ducting 3 which is to be tapped, for purposes of repair, maintenance or other treatment. In a situation wherein the aim of the exercise is to repair a damaged watermain, the tapping procedure will be carried out on opposed sides of the site where breakage has actually occurred. In the especially preferred embodiment illustrated the components 1A and 1B are adapted to be positioned around the watermain 3, as shown, and fixed in position relative thereto using any known means, as for example nuts and bolts or the like fixing means adapted, in use, to be located on those opposed flanged sections 1A and 1B of the off-take.

Once the off-take is located in the desired position, then a valving means 4 of any known type is located in any known manner, and using any known means, on the top-most free end of the flanged off-take component 1B. In the especially preferred embodiment the valving means 4 may be in the form of a knifegate valve which can be bolted, or in any other way affixed, to the top of that flanged off-take component lB.

Thereafter, an under-pressure tapping machine of any known type may be fitted to the knifegate valve 4, such machine to be employed to cut a hole into the pipeline 3 to match the nominal diameter of the pipeline 3 and a means to be employed for isolating a section thereof, generally in the form of plug or the like 5, to be described hereinafter in more detail. The plug 5 is preferably formed principally of rubber or a similar substantially rigid material and may be of a substantial bullet-shape when viewed in side elevation. That plug 5 includes a "floating" pin 6 disposed substantially centrally thereof, such pin 6 serving a practical purpose which will be described later in this specification in more detail.

The upper flanged component of 1B the off-take will include a centrally disposed through-bore of a size compatible with the plug 5. The plug 5 is adapted, in use, to be disposed within such through-bore. Means will then be provided for forcing the plug 5 in a direction axially of the flanged component 1 B, whereby to travel down into the pipeline 3 as shown in the drawings. In the preferred embodiment illustrated a driving plug 7 will be locatable within the through-bore of the component 1 B, in substantial physical contact with the uppermost surface of the plug 5. That driving plug 7 will function to force the plug down into the pipeline 3 itself.

30/01/04jfgf4757 spc,7 -8- Once a hole is cut into the pipeline 3 the knifegate valve 4 can be closed and the under-pressure tapping machine withdrawn. In accordance with the present invention the tapping machine is replaced with a means or tool whose purpose is to form or create a seating or groove 8 in the pipeline 3 itself. Once such tool is in position, the underpressure tapping machine can be returned to the knifegate valve 4 and the tool employed to grind the internal surface of the pipe until such time as a seating 8 is formed therein, for receiving and retaining the isolating means or plug 5. That seating 8 is formed in the cementitious lining material 9 of the pipeline 3 itself.

In order to ultimately provide for sealing of the thus tapped or cut watermain 3, an insertion chamber 10 is adapted to be, in use, associated with the knifegate valve assembly 4. That insertion chamber 10 includes an elongate chamber having a driving shaft 11 extending longitudinally thereof and relatively movable therein. At or in the vicinity of the innermost free end of the driving shaft 11 there are provided a plurality of driving lugs 12 extending laterally thereof, such lugs 12 serving a purpose to be described in more detail hereinafter. In the preferred embodiment illustrated suitable sealing means of any given type, as for example an O-ring 13, provides for sealing of the insertion chamber 10. At or in the vicinity of the uppermost end of the insertion chamber 10 there is preferably provided a pressure gauge and bleed-off means (air-bleeding valve) 14.

The driving plug assembly 7 in accordance with the present invention is, in use, hooked onto the lugs 12 of the driving shaft 11 of the insertion chamber 10 and withdrawn into the insertion chamber 10 itself, by retracting the driving shaft 11. When in that position within the insertion chamber 10 the insertion chamber 10 itself is then bolted onto the knifegate valve 4, and the valve 4 opened in order to pressurise the insertion chamber With the valve 4 fully open, the driving shaft 11 is pushed in a relatively downward direction to insert the plug assembly into the flanged off-take component 1B.

As illustrated the driving plug 7 itself will engage with or in an internal thread provided at or in the vicinity of the upper portion of the flanged off-take component 1B such that, as the driving shaft 11 is turned and moved downwardly, a downward force is exerted on the plug 5 whereby to encourage a seal in the watermain 3 itself after a predetermined torque has been achieved. In order to ensure appropriate sealing within the flanged off-take component 1B a suitable sealing means, as for example an O-ring, may be provided.

30/01/04jfgf4757 spc.8 When the plug 5 is thus inserted into the pipeline 3, both the knifegate valve 4 and the insertion chamber 10 are removed from contact with the off-take component 1B.

When the relevant procedures are completed, removal of the plug 5 may be achieved by reversing the aforementioned steps, with the water pressure in the insertion chamber 10 being equalised with that in pipeline 3 prior to removal of the driving plug 7.

A final, substantially leak-proof sealing is then achieved by screwing down the plug 5, as for example by means of the driving plug 7, until such time as the plug engages properly in the seating 8 previously formed in the cementitious material sleeve 9.

When in such location, the plug 5 is further supported by the floating pin 6, which moves in a vertical direction inside the plug 5 and allows the rubber material thereof to fully engage with the preformed seating 8, yet prevents lateral or sideways movement of the plug 5 within the pipeline 3, which might otherwise occur due to water pressure acting on one side of the plug 5 (the upstream side). Without the floating pin 6 there may be a potential for the plug 5 to flex sideways under pressure, which flexing could in turn lead to separation of the plug 5 from the seating 8, thereby giving rise to unwanted leakage.

The method and apparatus in accordance with the invention present substantial advantages over the prior art. More especially they provided a means which can readily isolate a given section of a pipeline, for whatever purpose whether to allow for repair of a damaged/broken pipeline, maintenance or connection thereto of another line or conduit.

Finally, it is to be understood that the aforegoing description refers merely to preferred embodiments of the invention, and that variations and modifications will be possible thereto without departing from the spirit and scope of the invention, the ambit of which is to be determined from the following claims.

30/01/04jfgf4757 spc,9

Claims (14)

1. A method for allowing a section of a pipeline (for carrying or supplying fluid) to be isolated, the method including the installation of a temporary plug in the pipeline while the pipeline is under pressure, yet still enabling repair and/or maintenance. work to be effected without lengthy interruption of supply, said method further including: drilling/tapping a hole in said pipeline of a predetermined size; forming a groove or seating around the internal diameter of said tapped pipeline; and locating a plug or the like flow interruption means through said tapped hole into said pipeline, the outer periphery of said plug of the like flow interruption means being adapted to be located within said formed groove/seating.

2. The method as claimed in claim 1, wherein said method includes the further steps of: locating a flanged off-take or tapping band at a desired location on said pipeline; introducing a valving means onto the top-most free end of said off-take or tapping band; attaching an under-pressure tapping machine to said valving means, whereby to form said hole in said pipeline; closing the valving means; withdrawing or removing the tapping machine, whereby to allow for formation of said groove/seating.

3. A plug or flow interruption means for use in the method as claimed in any one of the preceding claims, said plug preferably being constructed from a substantially rigid material and having a pin or the like member extending substantially centrally thereof, whereby to afford increased rigidity and prevent said plug exiting said groove/seating when under pressure.

4. The plug as claimed in claim 3, wherein said plug is constructed from a rubber or rubberised material.

5. The plug as claimed in claim 3 or claim 4, wherein said pin is formed of a metal.

6. Apparatus for the under-pressure sealing of a pipeline, said apparatus including: means adapted to be removably associated with said pipeline whereby to define a location for sealing and having a valve means associated therewith; means for under- pressure tapping of said pipeline; and plug means adapted to be disposed within said pipeline whereby to seal said pipeline against flow downstream of said location means, wherein said plug means is in the form of a substantially rigid member adapted, in use, to occupy the entire cross-section of said pipeline, whereby to provide a sealing effect for said pipeline. 30/01/04jfgf4757 -11-

7. The apparatus as claimed in claim 6, wherein said location means is in the form of a tapping band, adapted to be releasably associated with said pipeline at a desired location thereon, said tapping band including two complementary components, to be located respectively around the upper and lower portions of said pipeline, said upper component including a substantially centrally disposed throughbore.

8. The apparatus as claimed in claim 6 or claim 7, wherein said valve means is a knifegate valve.

9. The apparatus as claimed in any one of claims 6 to 8, wherein said location means are both flanged.

10. A method for the under-pressure sealing of a pipeline, said method including the steps of: locating a means for tapping said pipeline at a predetermined position thereon, said means for tapping having valve means associated therewith; tapping said pipeline at said predetermined position thereon; removing said means for tapping, whilst said valve means is closed; forming a groove or seating about at least a major part of the internal diameter/ periphery of said pipeline; locating a plug or the like means within said pipeline, said plug being adapted, in use, to have its outer periphery disposed within said groove or seating formed within said pipeline.

11. The method as claimed in claim 10, further including disposing a tapping band or flanged off-take at said predetermined position, said tapping band or off-take including two complementary components, to be located respectively around upper and lower portions of said pipeline, said upper component including a substantially centrally disposed throughbore.

12. A method for allowing a section of a pipeline to be isolated, substantially as described herein with reference to the accompanying drawings.

13. A plug or flow interruption means, substantially as described herein with reference to the accompanying drawings.

14. A method for the under-pressure sealing of a pipeline, substantially as described herein with reference to the accompanying drawings. Apparatus for the under-pressure sealing of a pipeline, substantially as described herein with reference to the accompanying drawings. DATED this 3 0 th day of January, 2004 30101/04jfgf4757 spc,I I 12 PTC GROUP PTY. LTD. By their Patent Attorneys: CALLINAN LAWRIE 30f01/04jfgf4757 spc, 12