METHOD OF SEALING A PIPE

Abstract

The invention relates to a method for preparing a pipe for a continuous spray lining process, the method comprising the following steps: providing an inflatable packer (3); providing an expandable sleeve (4) with a conformable backing layer (5) and an adhesive layer (6); wrapping the expandable sleeve around the packer with the adhesive layer facing the outside; inflating the inflatable packer until it reaches a first diameter (D.sub.1), wherein the first diameter is smaller than the inner diameter (d) of the pipe section, thereby expanding the stretching sleeve, inserting the inflated packer with the expanded sleeve into the pipe (1, 2) until it reaches the pipe section to be sealed; and further inflating the packer until it reaches a second diameter (D.sub.2), thereby further stretching the expandable sleeve; wherein the second diameter is reached when the expanded sleeve touches the inner diameter (d) of the pipe section.

Claims

1. Method for preparing a pipe for a continuous spray lining process, the method comprising the following steps: providing an inflatable packer, providing an expandable sleeve with a conformable backing layer and an adhesive layer, wrapping the expandable sleeve around the packer with the adhesive layer facing the outside, inflating the inflatable packer until it reaches a first diameter (D.sub.1), wherein the first diameter is smaller than the inner diameter (d) of the pipe section, thereby stretching the expandable sleeve, inserting the inflated packer with the expanded sleeve into the pipe until it reaches the pipe section to be sealed, and further inflating the packer until it reaches a second diameter (D.sub.2), thereby further stretching the expandable sleeve, wherein the second diameter is reached when the expanded sleeve touches the inner diameter (d) of the pipe section.

2. Method according to claim 1, wherein the method comprises the step of further inflating the packer to provide a radially applied pressure onto the expanded sleeve to facilitate adhesion of the sleeve at the pipe.

3. Method according to claim 2, wherein the radially applied pressure can be up to 15 bar, preferably 2 to 5 bar.

4. Method according to claim 1, wherein the radially applied pressure is maintained for two to five minutes.

5. Method according to claim 1, wherein the force of the adhesive in the adhesive layer is strong enough to hold the expandable sleeve in its expanded stage at the inner wall of the pipe section.

6. Method according to claim 1, wherein the pipe section comprises a hole, a gap between two pipes joining each other or any other kind of circumferential discontinuity.

7. Method according to claim 1, wherein the backing layer of the sleeve is a polymeric backing layer.

8. Method according to claim 7, wherein the backing layer of the sleeve is a flexible metal backing layer.

9. Method according to claim 8, wherein the flexible metal layer of the sleeve is chosen from either aluminium or copper sheet or film.

10. Method according to claim 7, wherein the polymeric backing layer comprises polyurethane, polyethylene or co-polymers thereof, synthetic rubber or PVC.

11. Method according to claim 1, wherein the adhesive layer comprises an acrylic based, a rubber based or a mastic compound.

12. Method according to claim 10, wherein the adhesive layer comprises a foam sub-layer.

13. Method according to claim 1, wherein the expandable sleeve is provided as a flat sheet, pre-cut into a rectangular shape with two opposing end regions to size for the according pipe inner diameter.

14. Method according to claim 11, wherein the expandable sleeve is positioned around the inflatable packer such that the two opposing end regions overlap each other.

15. Method according to claim 11, wherein the overlapping ends overlapped each other by 10 to 40 mm so as to form a cylindrical sleeve.

16. Method according to any of the claims 1, wherein the expandable sleeve is provided as an elongated substantially cylindrical sleeve with a diameter to size for the according pipe inner diameter.

17. Use of an expandable sleeve comprising a backing layer and an adhesive layer for sealing an inner pipe section, wherein the sleeve is applied in an expanded stage to the pipe section.

Description

[0045] The invention will now be described in more detail with reference to the following Figures exemplifying particular embodiments of the invention:

[0046] FIG. 1 is a cross-sectional view of a pipe section with an inflatable packer outside of the pipe section, the inflatable packer comprising a diameter D.sub.0;

[0047] FIG. 2 is a cross-sectional view of a pipe section with an inflatable packer outside of the pipe section, the inflatable packer comprising a diameter D.sub.0, the inflatable packer further comprising a sleeve being wrapped around the packer;

[0048] FIG. 3 is a cross-sectional view of the pipe section of FIG. 1 with the inflatable packer outside of the pipe section, the inflatable packer comprising a diameter D.sub.1, D.sub.1 being bigger than D.sub.0 and smaller than the inner diameter of the pipe d;

[0049] FIG. 4 is a cross-sectional view of a pipe section of FIG. 1 with the inflatable packer with its diameter D.sub.1 being inserted into the pipe;

[0050] FIG. 5 is a cross-sectional view of a pipe section of FIG. 1 with the inflatable packer being inserted into the pipe and the inflatable packer being inflated to a diameter D.sub.2 equal to the inner diameter of the pipe section;

[0051] FIG. 6 is a cross-sectional view of an expandable sleeve wrapped around the inflatable packer;

[0052] FIG. 7 is cross-sectional view of the pipe section of FIG. 1 with the expandable sleeve being attached to the inner wall of the pipe section and

[0053] FIG. 8 is a cross-sectional view of a larger part the pipe section of FIG. 1 with the expandable sleeve being attached to the inner wall of the pipe section and a coating being provided inside of the pipe section covering its inner wall as well as the sleeve.

[0054] FIG. 1 is a cross-sectional view of a pipe section. The pipe section is a joint of two ends of pipes 1 and 2. The inner diameter of the pipes 1 and 2 is d, wherein the end section of the pipe 1 provides an enlarged inner diameter d.sub.1 to receive an opposing end section of the pipe 2. In that joint a gap 9 exists between the end of pipe 2 and the enlarged section of pipe 1. The materials used in in-situ maintenance procedures, e.g. in in-situ spray coating processes may have limitations in their ability to fill or span circumferential discontinuities, such as for example those discontinuities showed in FIG. 1, a gap 9 due to a joint of pipes. In order to prepare the pipe section for the in-situ spray coating process, the herein described embodiment provides a pre-treatment of the pipe.

[0055] For the pre-treatment an inflatable packer is used that provides means for inflating the packer in order to change its diameter. The inflatable packer also provides mechanical means for moving it into, along the pipe and back out of the pipe. In addition, the inflatable packer provides means for centering the packer that positions the packer in the middle of the pipe. These mechanical and centering means are not shown in the drawings to ensure clarity in the drawings.

[0056] FIG. 1 also schematically shows an inflatable packer 3 outside of the pipe section. The inflatable packer is in an uninflated stage and provides a diameter D.sub.0, which is smaller than the diameter d of the pipes 1 and 2.

[0057] FIG. 2 is a cross-sectional view of the same pipe section of pipes 1 and 2 and the inflatable packer 3, wherein the inflatable packer 3 is in its uninflated stage with a diameter D.sub.0. An expandable sleeve 4 is wrapped around the inflatable packer such that the end portions 7 and 8 of the sleeve 4 overlap each other (see FIG. 6).

[0058] FIG. 3 is a cross-sectional view of the same pipe section of pipes 1 and 2 and the inflatable packer 3, wherein the inflatable packer 3 has now been inflated up to a first diameter D.sub.1, which is larger than D.sub.0 but still smaller than d, the diameter of the pipes 1 and 2. The expandable sleeve 4, which is wrapped around the packer 3, is stretched due to the inflation of the packer 3. By slightly stretching the sleeve 4 it is guaranteed that the sleeve is positioned onto the packer 3 and does not move relative to each other during the next process steps.

[0059] As can be seen in FIG. 6 which shows a radial cross-section of the inflatable packer 3 with an expandable sleeve 4 wrapped around the packer 3, the sleeve 4 comprises two layers a backing layer 5 and an adhesive layer 6. The adhesive layer is facing the outside in FIG. 6. The sleeve 4 provides two opposing end regions 7 and 8, wherein the two opposing end regions 7 and 8 overlap each other when the sleeve 4 is wrapped around the inflatable packer 3. Since the adhesive layer 6 is facing the outside of the sleeve 4 the overlapping end 8 becomes adhered to the overlapping end 7 due to the adhesive layer 6 of the overlapping end 7 getting in contact with the backing layer 5 of the opposing end 8. Thereby the sleeve 4 becomes fixed in its cylindrical shape.

[0060] Next the inflatable packer 3 with the thereon positioned sleeve 4 is inserted into the pipe until it reaches the pipe section to be sealed (see FIG. 3). The packer 3 should be located centrally over the joint. Means of cameras may be used to ensure proper positioning. Lasers may optionally be used as well to aid in achieving proper location of the sleeve 4 at the joint. When the packer 3 has reached the pipe section to be sealed it is inflated to the diameter D.sub.2 which corresponds to the inner diameter of the pipes 1 and 2. Since the overlapping ends 8 and 7 are fixed relative to each other and do not move relative to each other, the sleeve 4 further expands until the adhesive layer 6 of the expandable sleeve 4 touches or contacts the inner walls of the pipes 1 and 2 (see FIG. 5).

[0061] The inflatable packer 3 may get even more inflated or pressurized in this position in order to provide a suitable pressure onto the expanded sleeve 4 to facilitate adequate adhesion of the sleeve 4 at the inner wall of the pipes 1 and 2. The pressure radially applied to the sleeve can be up to 15 bar, the pressure referring to the pressure inside of the packer 3. Preferably it is between 2 and 5 bar. The pressure may be maintained for two to five minutes in order to assure reliable adhesion of the sleeve at the inner wall of the pipes 1 and 2. After this time the inflatable packer 3 may be deflated and moved out of the pipe again. The packer 3 may then be reloaded with another sleeve and deployed at the next spot to be sealed, e.g., at the next joint. When all spots are sealed the pipe is ready for an in-situ spray coating or lining which may leads to rehabilitation of the pipe.

[0062] FIG. 7 is a cross-sectional view of the pipe section with the joint of pipes 1 and 2 with the expanded sleeve 3 being adhered to the inner wall of the pipe section thereby extending over the gap 9, that exists due to the geometry of the pipe joint, wherein the pipe 1 provides an extended diameter to receive an end section of the pipe 2. The extended sleeve 3 provides a seal for the gap 9 and therefore facilitates a reliable in-situ spray coating process. The result of a spray coating step can be seen in FIG. 8 which is a cross-sectional view of the pipe section of FIG. 7 with an additional layer of resin coating 11 the inner walls of the pipes 1 and 2 as well as the expanded sleeve 3 extending over the pipe joint.

[0063] Examples for sleeve materials that were tested and performed suitably are the following (all commercially available from 3M Company, St. Paul, Minn., US): [0064] 3M Polyurethane Protective Tape 8641 [0065] 3M Polyurethane Protective Tape 8641 (perforated) [0066] 3M Rubber Mastic 2228 [0067] 3M Extreme Sealing Tape 4411N [0068] 3M Extreme Sealing Tape 4412N [0069] 3M All Weather Flashing 8067 [0070] 3M Cable Jacket Repair Tape 2234

[0071] The 3M (Aircraft Belly) Protective Tape 8641 is an exceptionally tough 16-mil thick polyurethane coated with an aggressive, conformable 25-mil thick pressure sensitive acrylic foam adhesive.

[0072] The 3M Rubber Mastic 2228 is a conformable self-fusing rubber electrical insulating and sealing tape. It consists of an ethylene propylene rubber (EPR) backing coated with an aggressive temperature-stable mastic adhesive.

[0073] The 3M Extreme Sealing Tape 4411N, 4412N are tapes out of a family of single coated, pressure sensitive adhesive tapes designed for sealing applications. The backing on this tape is an ionomer film that is very tough yet flexible and abrasion resistant. The very soft and thick acrylic adhesive has excellent sealing properties.

[0074] This single coated tape is designed to seal over an existing joint, seam or penetration. The adhesive is designed to adhere well to the ionomer film so that overlapping tape joints can be adhered while maintaining a strong seal.

[0075] The 3M All Weather Flashing 8067 is a self-adhered, waterproof flashing membrane designed for sealing around openings and penetrations in exterior walls. It has a unique acrylic pressure sensitive adhesive that aggressively sticks to all applicable surfaces and a proprietary backing with sealing function.

[0076] 3M Cable Jacket Repair Tape 2234 is a two layer tape with an outer layer of vulcanized CSM rubber to provide outstanding chemical and environmental resistance. The inner layer is composed of flame-retardant mastic and acts as a moisture barrier which provides excellent adhesion to a variety of jacket materials.

TABLE-US-00001 Adhesive Adhesive Robustness Conformability Tape Thickness Backing Type Type Properties of Backing in Pipe 3M 1 mm Polyurethane Acrylic 5 9 9 Polyurethane (foam Protective carrier) tape 8641 3M 1 mm Polyurethane Acrylic 5 9 9 Polyurethane (foam Protective carrier) tape 8641 (Perforated) 3M Rubber 1.65 mm Rubber (EPR) Mastic 5 5 9 Mastic 2228 3M 1 mm Ethylene/Acrylic Acrylic 9 9 9 Extreme co- (foam Sealing polymer carrier) Tape 4411N 3M 2 mm Ethylene/Acrylic Acrylic 9 9 5 Extreme co- (foam Sealing polymer carrier) Tape 4412N 3M All 0.13 mm Acrylic Acrylic 9 5 1 Weather Flashing 8067 3M Cable 1.5 mm Rubber (EPR) Mastic 5 1 5 Jacket Repair Tape 2234 3M 1.1 green rubber 5 9 9 Sandblast polyethylene adhesive Stencil- film Hand Cut Splice Free 507 Green 3M 1.1 green Acrylic 9 9 9 Sandblast polyethylene (foam Stencil- film carrier) Hand Cut Splice Free 507 Green Amerimax 2.0 Aluminum Acrylic 9 9 5 Aluminum sheet (foam Valley carrier) Flashing

TABLE-US-00002 Conformability in pipe. (Tested in 100 mm PVC Value Adhesive properties Robustness pipe barrel) 1 Easily detached from Lifting of edges and/or tearing Begins detachment from substrate (e.g. cast iron, of backing following dragging pipe wall within 5 minutes steel) with minimal of a steel panel over surface. of installation. resistance. 5 Detached from substrate Marking of edges or backing Begins detachment from (e.g. cast iron, steel) with following dragging of steel pipe wall within 24 Hours significant force. panel (visual only). of installation. 9 Unable to remove from No sign of lifting or marking of Remains fully bonded to substrate (e.g. cast iron, tape backing following pipe wall 24 Hours after steel) without a cohesive dragging of steel panel. installation. breakdown of tape.

[0077] All sleeve materials were tested when applied to the internal surface of a 100 mm diameter of a steel pipe via an inflatable packer. The 3M Extreme Sealing Tape 4411 showed excellent adhesive properties, excellent robustness of the backing and excellent conformability in the pipe and were therefore rated as very promising.