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Title:
METHOD FOR MAKING AN END PORTION OF AN INTERNAL LINING SHEATH FOR PIPELINES
Document Type and Number:
WIPO Patent Application WO/2012/104801
Kind Code:
A1
Abstract:
Method for the formation of the terminal section (11, 1 1') of a sheath (2, 2') to line the inside of a pipeline, which includes the following stages: application of an inner lining sheath (2, 2') to a pipe (1); application at one end of the pipe of a mould (3, 3') to create a chamber delimited by the actual mould, by the end of the pipe and by the said sheath; injection in the said chamber of a suitable resin, preferably a hardening resin; hardening of the said resin; removal of the said mould.

Inventors:
DINI STEFANO (IT)
Application Number:
IB2012/050472
Publication Date:
August 09, 2012
Filing Date:
February 01, 2012
Export Citation:
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Assignee:
IDROAMBIENTE S R L (IT)
DINI STEFANO (IT)
International Classes:
F16L55/165; F16L23/024; F16L23/12
Foreign References:
JPH06286013A1994-10-11
JPH07171908A1995-07-11
JPH09201848A1997-08-05
US5778937A1998-07-14
Other References:
None
Attorney, Agent or Firm:
JAUMANN, Paolo (Via San Giovanni sul Muro13, Milano, I-20121, IT)
Download PDF:
Claims:
CLAIMS

1. Method for the formation of the terminal section (1 1 , 1 1 ') of a sheath (2, 2') to line the inside of a pipeline, which includes the following stages:

application of an inner lining sheath (2, 2') to a pipe (1);

application at one end of the pipe of a mould (3, 3') to create a chamber delimited by the actual mould, by the end of the pipe and by the said sheath;

injection in the said chamber of a suitable resin, preferably a hardening resin;

hardening of the said resin;

removal of the said mould.

2. Method according to claim 1 , wherein the said resin is a hardening resin compatible with a hardening resin that impregnates the said sheath;

3. Method according to claim 1 or 2, wherein the sheath is applied before or after the mould.

4. Method according to any previous claim, wherein the said sheath juts out from the said pipe for a suitable length and the said chamber is delimited by the external surface (6) of the said sheath, in the said section; the method optionally includes the removal of the part of the said section in excess of the terminal section formed by the resin injected in the mould.

5. Method according to any previous claim, wherein the end of the pipe features a connection element (4) in particular a flange, to connect the pipe to another pipeline component ( 13), fitted with a corresponding connection element.

6. Method according to claim 5, wherein the said connection element is a flange (4), and the chamber is delimited by a front surface of the said flange that faces the corresponding front surface of the flange of another component.

7. Method according to any claim from 1 to 4, wherein the chamber (5') is delimited by a part of the external wall of the pipe so that the section formed (11 ') can line a part of the external surface of the said pipe and be connected to the sheath at the edge of the pipe ( 16); the said part of the external wall of the pipe can be duly covered by an elbow coupling joint (for example a Straub joint).

8. Method according to claim 2, wherein the resin that impregnates the sheath is of the epoxy type and the one injected in the chamber is of the polyurethane type.

9. Method according to claim 8, wherein the resin is injected in the chamber before the resin that impregnates the sheath has completely hardened, or optionally at a partial level of hardening of the resin that impregnates the sheath.

10. Sheath to line the inside of pipelines, with a terminal section (1 1 , 1 Γ) that is an integral part of the said sheath and radically juts out from the said sheath; in particular, the sheath is created according to the method specified in claims from 1 to 9.

1 1. Pipe fitted with sheath according to claim 10, wherein the said section covers the surface of a connection element or the external wall of the said pipe at, at least, one end of the said pipe.

12. Mould, in particular made of silicone plastic, to be used in the method specified in claims from 1 to 9.

Description:
TITLE

"METHOD FOR MAKING AN END PORTION OF AN INTERNAL LINING SHEATH FOR PIPELINES"

DESCRIPTION

The present invention relates to a method for the formation of a terminal section of an inner lining sheath applicable to a pipeline section during an inner lining (or relining) operation. According to a preferred aspect, the terminal section acts as a gasket, for example between two flanges that join the pipeline section, subjected to the lining operation, to an adjacent pipe section, or to a valve or other structure, or between the end of the pipeline section and an external joint (elbow couplings, for example with Straub joint or similar).

Relining procedures are commonly used for the maintenance or repair of pipeline sections, in particular of sections which are difficult to replace.

The lining is usually made up of a sheath of duly woven material impregnated with glue, resin, tar or other appropriate binder, usually hardening resin; the sheet is applied to the internal surface of the pipeline, usually with the edges positioned side by side along a generating line and duly impregnated to provide continuity. The fabric could be for example a matt, for example made of polyester, and the sheath may include different layers of different materials according to the requirements; for example other fabrics or matts of different fibres, such as glass fibres or other fibres. In general, a layer of appropriate lining material is also foreseen, such as polyethylene or polyurethane, which is attached internally to the sheath and is in contact with the fluid that flows through the pipe. The resin can be hardened using different methods depending on the type of resin; it can be cold or hot hardened, for example using steam circulation or hot air, or by means of light or ultraviolet radiation using appropriate lamps. Continuous lining can be applied to very long pipeline sections that also feature different pipes connected by joints such as flanges or other joining elements.

Different solutions are adopted for the end of the section being lined, where the latter joins onto another pipeline section or another pipeline element, such as for example a valve, cover, fitting, rupture disc, meter...

The simplest solution is to cut the lining flush to the end of the pipeline section concerned. This solution is only possible if there is an adequate adhesion and hold between pipe and resin along the entire pipeline section concerned; this usually depends if the pipeline surface can be processed and on its conditions of deterioration. In the case of old pipes, or non metal ones, these requisites are rarely met. To improve the adhesion, the terminal part of the lining can be covered with adequate products such as polymers, tar, suitable types of cement, or even better with hardening resins. The sheath however is not always adequately protected against structural stress and the lining can often become detached, even during the assembly of the connection. Furthermore, hardening products require a long setting time.

Good stress resistance can be obtained by means of internal ribbing, usually made of stainless steel, with the ribs separated and blocked by suitable lock plates. A sleeve made of elastomeric material, for example, can be applied inside the lining and blocked at the ends by at least two ribs. This system takes a long time and reduces the internal diameter of the pipes, making it irregular with consequent losses in pipe flow rate when operational.

Finally, stainless steel sheet terminal parts are sometimes applied, separated by screw supports, wedges or other systems and then fixed with locking wedges or by welding. The said terminal parts require the lining to be spread on the application area using sealants such as silicone; they are not very stable and resistance to mechanical stress is poor. This solution, like the previous one, is difficult to apply in the case of small pipeline diameters.

In addition, certain types of sealants do not adhere well to certain types of resin, such as polyethylene, used in composite type linings for the side facing the fluid.

All the methods described are incompatible with the use of cleaning and inspection devices (known as pigs, i.e. pipeline inspection gauges).

Finally, if the pipeline is subjected to great differences in temperature the flush cutting method is not applicable, and the other systems may be affected by the stress in the long term.

It would be desirable to guarantee a perfect adhesion and adequate resistance to stress of the ends of the lining, without the need however to apply structures or devices that reduce the internal diameter.

It would be desirable to have a solution which is easy to apply to pipes of any diameter, without the above mentioned inconveniences. The said objective has now been achieved, according to this invention, by a method for the formation of the terminal section of a sheath to line the inside of a pipeline, which includes the following stages:

application of an inner lining sheath to a pipe;

application at one end of the pipe of a mould to create a chamber delimited by the actual mould, by the end of the pipe and by the said sheath;

injection in the said chamber of a suitable resin, preferably a hardening resin;

hardening of the said resin;

removal of the said mould.

The application of the sheath and the application of the mould can be executed in any order.

The pipe can be part of a pipeline or part of a section of a pipeline, which may include a number of pipes, to which the sheath is applied. According to a preferred embodiment, the said sheath juts out of the pipe for a suitable length and the said chamber is delimited by the external surface of the lining, in the said section. The external surface is, in particular, the surface of the sheath which, inside the pipe, is in contact with the pipe's internal wall. The part of the said section which, after the removal of the mould, juts out from the terminal part formed by the injected resin, can be later removed, according to a possible aspect of the invention.

According to a particular aspect of the invention, the end of the pipe includes a connection element (for example a flange or collar) to connect the pipe to another pipeline component such as a pipe, fitting, valve, cover or rupture disc, meter or other suitable component, fitted with a corresponding connection element. According to a preferred aspect, if the said connection element is a flange, the chamber is delimited by a front surface of the said flange that faces the corresponding front surface of the flange of another component. The terminal section formed, thus juts out and comes in contact with the said front surface and can act as gasket between the flange and the flange of the component to be connected to the pipe. According to another aspect, the chamber is delimited on one side by a part of the external wall of the pipe so that the section formed can line a part of the external surface of the said pipe and be connected to the sheath at the edge of the pipe. The part of the external wall of the pipe can be duly covered by an elbow coupling joint (for example a Straub joint). According to a preferred aspect, the injected resin is the same resin as, or is compatible with, the resin that impregnates the sheath, so that the section formed is an integral part of the actual sheath, creating a chemical bond between the resins or in any case providing adequate adhesion. According to a preferred aspect, the resin that impregnates the sheath can be of the epoxy type and the one injected in the chamber can be of the polyurethane type.

The content of the enclosed claims constitutes particular scope of the invention.

The invention will now be better illustrated by means of the description of preferred embodiments, provided in the form of non- limiting examples, with the help of the accompanying drawings, in which:

la, lb, lc, Id, le and If, represent, schematically, various stages of a method according to the present invention, applied to a flanged pipe; figures 2a and 2b represent, schematically, the stages of a similar method, with a particular shape of the mould;

figures 3a, 3b and 3c represent, schematically, the stages of a method according to this invention, applied to a pipe to be connected to another pipe with an elbow coupling and execution of the said coupling;

figure 4 represents, schematically, a coupling formed between the pipe treated with the method described in figures la-le and another pipeline component. The sheath, of a known type, is applied to the pipe using known methods. The sheath may include one or more layers of fabric impregnated with resin, preferably of a suitable hardening type, for example polyurethane or preferably epoxy resin. The term fabric is understood to also include matts, for example polyester fibre matts. The sheath can also include a layer of surface lining, which will cover the surface that faces the fluid. The application of the sheath includes the hardening of the resin, in an adequate manner, according to the type of resin; the resins can be hardened using steam circulation or hot air, or light or ultraviolet radiation or simply, for these types of resins, by mixing several components, or in any other known manner.

With reference to figures from la to If, sheath 2 is applied to pipe 1. According to a possible aspect, the pipe can feature a flange 4 at the end. A mould 3 of the appropriate shape, suitable for the end of the pipe, is applied to the end of the pipe.

If the end features a flange, as shown in the figures concerned, the mould can create, as shown in figure lc, a chamber 5 delimited by the front surface 7 of the flange, by the mould and by the external surface 6 of the sheath, which, according to a possible aspect of the invention, inside the pipe adheres to the pipe's internal wall. As shown, the sheath is made to preferably jut out for an appropriate section from the pipe, so it adheres to the mould. According to a preferred aspect, the mould features an opening 8 of a shape that corresponds to the sheath, so it can be fitted to the said section. According to a further preferred aspect, the mould features an internal surface 10 that adheres to the outer edge 9 of the sheath. According to a further aspect of the invention, the mould can feature breather holes 20, duly arranged, to allow the chamber 5 to be filled; for example the breather holes can be positioned so that they are on the top when the mould is being used. A duly positioned resin input hole 21 can also be foreseen, which can alternatively be used for a supply line. The figures illustrate the case in which the mould is applied before the sheath, but the sheath can be applied before the mould, which can be fitted, in a similar case to that of the figures concerned, on the section of the sheath jutting out of the pipe. Figures Id and le show the injection stage of a resin, preferably of the hardening type, in the said chamber until it is full. Once the resin has adequately hardened, the mould can be removed. The part of the said section of the sheath jutting out of the pipe can be preferably removed, for example cut, as shown in figure le. If considered appropriate and acceptable, it can be left. It shall extend into a pipeline component to be joined to pipe 1.

The section 11, formed with the process according to this invention is an integral part of the sheath, partially represented with section view in figure le, and radically juts out of the sheath; it is retained by the end of the positioned pipe, preventing the detachment of the sheath when the pipe is in use and when subjected to mechanical or fluid dynamic stress. As shown is figure 4, the section 11 can also act as gasket between the flange 4 of the pipe 1 and the corresponding flange 12 of a pipeline component 13 connected to the former pipe. The mould used can be shaped so that the surface of the section 1 1 , that faces the component to be joined, is suitable for the flange of the said component; for example, if foreseen, it can feature ring projections or grooves that correspond to grooves and projections on the flange. It is clear that the section will adhere and adapt perfectly to the flange 4 of pipe 1. As shown in figures la- Id, the mould can have projections 14 to close the holes of the flange 4 and create corresponding holes in section 1 1 for the connection screws. Other solutions are possible, and the holes in the flange can for example be closed in another way or they can be used as breather holes, if deemed suitable. The holes on section 11 can also be made after the hardening stage.

If, as shown here by way of an example, the mould features an opening to house the section of sheath 2 jutting out from the pipe, as shown by way of example in figure 4, means can be foreseen to improve adhesion and to mutually hold the mould and sheath in position, such as an elastic lip 15 incorporated in the mould.

Figures 3a- 3c, show the case of a pipe without flange, intended to be connected to another component 13' by means of an elbow coupling.

The mould 3' can form a chamber 5' delimited by the sheath, by the edge 16 of the end of the pipe and by part of the external wall 17 of the pipe, so that the section 1 1 ' formed covers the said part of the external wall and connects onto the edge 16 of the sheath 2'.

As shown in figure 3c, once the joint 18 of the elbow coupling has been applied, the section 11 ' can be held in place by the joint 18 and in turn the said section 11 ' holds in place the sheath, so that the latter is resistant to mechanical and fluid dynamic stress. The section 1 1 ' can cooperate with a gasket 19 of the coupling to act as seal. The section 11 ' can also replace the coupling gasket, and if required it can be made of an appropriate shape, for example with ring projections or other elements in order to cooperate directly with the joint 18 to act as seal. For all cases not described, the coupling can be created and applied according to known methods.

In the cases described, if they feature a preferred embodiment of the invention, there is a sheath section jutting out of the pipe which is housed in a special opening in the mould. Other solutions are possible, such as a mould made to adhere to the internal surface of the sheath. In this case, the sheath can be cut flush before the application of the mould and the sheath will delimit the chamber with the cut outer edge.

According to a possible aspect, hardening resin is injected in the chamber when the resin that impregnates the sheath has almost completely, but not completely, hardened, so that the section formed is an integral part of the rest of the sheath once both resins have hardened. The said embodiment allows the formation of a strong bond between the sheath and the formed section. Other solutions are possible according to the resins used. Resins can be of a known type, adequately selected.

As mentioned, a preferred resin to be injected can be a polyurethane resin. It can harden in the mould after its components have been mixed, without the need to apply heat, and it is compatible with epoxy resins commonly used to impregnate the sheath. If the section formed must act as gasket for the coupling, this will be taken into consideration when selecting the resin to be injected, so that it will have suitable characteristics. In particular the hardness of the hardened resin can be, by way of a non-limiting example, between 60 and 97 Shore A. The thickness of the section formed must also be suitable; by way of a non-limiting example it can be between 1 and 10 mm or more, also depending on the size of the coupling.

If required, the injected resin may include reinforcement fibres, such as glass fibres, polyester fibres or other types. Before the injection of reinforcement structures for the said section, it is possible to insert fabrics in the mould, for example matts the same as or different from those that make up the sheath.

The mould can be made of any suitable material. Preferably it should be a material that does not stick to the resin, thus avoiding the use of release agents. Preferably, the material is adequately flexible to favour the removal of the mould if made of one single piece, even if small undercuts are present. A preferred material is silicone plastic. Other solutions are however possible, also with moulds made up of different parts for more complex shapes of the section or with moulds made of other materials such as aluminium, with the use of release agents.

It should be noted that the method according to the present invention makes it possible to create a single internal lining sheath, with a section that extends radically outwards from the sheath, to act as seal in a connection coupling with another pipeline component connected to the lined pipe. Without reducing the internal diameter of the pipe, similarly to the commonly known flush cut sheaths, the contact between the pipe wall and the sheath is protected, thus avoiding detachments and infiltrations. The section formed is also retained by the coupling which is formed, thus stopping the sheath from slipping, also in case of thermal expansion of the pipe. Furthermore, the resistance of the sheath and the lack of additional structures inside the pipe, allows the use of cleaning devices such as pigs. Furthermore, the section formed in this way adapts perfectly to the surface of the end of a pipe, better than any available preformed gasket, also in the case of defects or irregularities on the surface. This aspect can be of particular interest, given that the pipelines that require relining are often old or deteriorated pipelines which it is not possible to, or it is not convenient to, replace.