FR2607899A1 - Connection device for a pipeline and method of repairing such pipelines - Google Patents

Abstract

The invention relates to a connection device for a pipeline and a method of repairing such pipelines. It will particularly find its application in steelworks and more precisely for sealed pipelines conveying hot fluids. The connection device 9 of the present invention is intended for repairing existing pipelines 1 in the vicinity of the expansion compensator 2 interposed between two sections of pipes. In this respect, it is composed of at least two half-shells forming, on the one hand, a sealed chamber and exhibiting, on the other hand, means which can be expanded in concertina fashion or which are corrugated, capable of being placed around the said existing compensator so as to be substituted for it and so as to be secured to each other and onto the pipeline.

Description

The invention relates to a device for
pipe connection as well as a method of
pipeline repair using said device.

The present invention will find its application in
the field of watertight pipes conveying gaseous or liquid fluids, for example in steel installations.

 In fact, in the steel industry, the processing of iron ores is carried out in blast furnace installations, which consist of the blast furnace itself and various auxiliary devices. These different organs are joined together and it is known that leaktight pipes convey hot gaseous fluids.

 Such pipes are generally formed by the assembly of several sections of pipes together as shown in Figure 1 of this application.

However, the fluid circulating inside these pipes being generally at a high temperature, it is necessary to provide expansion compensators which allow elongations in operation, elongations which can be relatively significant because of the length of the pipes which can sometimes reaching five hundred meters.

 To admit these expansions, the pipes are in places integrally connected to the ground to form fixed points while in other places the pipes are supported by rolling contacts, generally arranged on either side of the expansion compensators, to authorize longitudinal movements.

 Naturally, it is interesting that these pipes are sealed to avoid on the one hand gas leaks which could be harmful and on the other hand heat loss because very often the heat is recovered for other purposes.

 The known expansion compensators consist of a connection sleeve which has expandable accordion or wavy means, such a type of compensator is illustrated in FIG. 2 appended to the present application.

 More specifically, the compensator is formed by a circular sleeve capable of being interposed in the pipeline between two sections of pipes and having for this purpose means for authorizing the introduction of the pipes on either side of the sleeve. In addition, in its central part it has expansion waves, generally obtained by forming the sheet of the sleeve.

 These waves are determined so that they can allow the pipes to expand on either side of the compensator in order to allow their elongation caused by the rise in temperature of the fluid circulating inside them. The operating principle of this compensator is illustrated in particular in FIG. 3 in which the strong lines represent the waves in the ambient temperature position and the dashed dashed lines represent the waves when the pipes are expanded.

 However, it should be noted that, given the difficult working conditions of these compensators, external and internal corrosion, it happens that at the level of these compensators the pipe presents leaks which are detrimental for the environment and the good operation of facilities. These leaks are caused due to the aging of the materials, the welds, and there then occurs cracks or holes which can grow until the compensator breaks.

 Furthermore, given the very specific nature of steel installations, due to their inertia both to put them into service and to stop them, it is unthinkable to immobilize such installations in such damage.

 However, changing a expansion compensator interposed between two series of pipes requires stopping the service of the pipeline, physically cutting it and reinstalling a new compensator.

 The object of the present invention is to provide a connection device for pipes such as in particular leaktight pipes conveying hot fluids in steel plants, which allows their repair in the event of a defect in expansion compensators without thereby requiring sectioning. of the offending pipeline or force the installation to be interrupted for an extended period of time.

 One of the aims of the present invention is to propose a connection device for piping, as well as a repair method using said connection device, which allow the substitution of a expansion compensator by a new device without significant intervention at the level of the pipeline and which even allow intervention on the pipeline in service.

 Other objects and advantages of the present invention will appear during the description which follows which is however given only for information and which is not intended to limit it.

 According to the invention, the pipe connection device, such as in particular leaktight pipes conveying hot fluids in steel plants, said pipe having at least two sections of pipes between which a expansion compensator is interposed, said connection device being in particular intended for the repair of existing pipes at the level of said waterproof expansion compensator, is characterized in that it is composed of at least two half-shells, forming on the one hand a sealing chamber, and having on the other part of the expandable means in accordion or wavy, able to be placed around said existing compensator to replace it and to be joined together and on the pipe.

The method of repairing pipes, such as in particular leaktight pipes conveying hot fluids in steel plants, said pipe having at least two sections of pipes between which a expansion compensator is interposed, said process using the device for connecting the present invention, is characterized in that
- the defective expansion compensator is left in place, on the existing pipe,
around said defective expansion compensator, there are at least two half-shells, forming a sealing chamber and means of expansion,
- said half-shells are joined together in leaktight manner,
- Said half-shells are joined in a sealed manner on said pipe on either side of said defective expansion compensator.

The invention will be better understood on reading the following description accompanied by the accompanying drawings, among which
FIG. 1 diagrammatically shows a sealed pipe conveying fluids causing expansion of the pipes,
FIG. 2 schematically represents an expansion compensator mounted on an existing pipe,
FIG. 3 illustrates the operating principle of the expansion compensator,
FIG. 4 shows in partial section a connection device for a pipe according to the present invention installed on an existing pipe at the level of said expansion compensator,
FIG. 5 shows another embodiment of the pcur pipe connection device of the present invention,
FIG. 6 shows a front view of a third embodiment of the pipe connection device according to the present invention,
- Figure 7 shows a front view of the device shown in Figure 6.

 The invention relates to a connection device for pipes, more precisely an expandable connection device intended for the repair of existing pipes.

 The invention also relates to a method for repairing watertight pipes carrying fluids capable of causing lengthening which is sensitive to said pipe.

 In fact, for example in steel installations, certain pipelines convey fluids at a high temperature, which causes very appreciable lengthening of the pipelines since they circulate over very long distances up to a few hundred meters.

 However, the invention has been more particularly developed in the case where the pipes convey hot fluids, but one could also envisage negative elongations during circulation of cold fluids, the principle of the invention being entirely applicable.

 It is known from the embodiments of pipelines which are subject to elongation; Figure 1 illustrates an example.

 These pipes having significant lengths, in order to avoid unacceptable stresses in the pipes, different expansion compensators (2) are distributed at regular intervals over the pipe (2) in order to allow the different sections (3), (4), ( 5) forming the pipe (1) to expand.

 For this, fixed points (6) of the pipeline (1) are established relative to the ground and rolling bearings (7) are placed on either side of the compensators (2) in order to support the pipeline while allowing its longitudinal displacement.

 FIG. 2 schematically represents a expansion compensator (2) interposed, during the construction of the pipeline (1), between two sections of pipes (4) and (5), this compensator being such that it connects the two sections of pipes in a tight manner.

 Such devices are known from the state of the art and the expansion means are formed by accordion waves calculated and determined according to the diameter of the pipes, the pressure flowing in the pipes, the temperature of the fluid and the material of the composition. compensator.

 During commissioning, the fluid flowing in the pipe (1) causes the heating of the wall of the pipes (3) to (5) and therefore causes an elongation which is reflected in the compensators (2) according to the arrows (8) shown in Figure 2.

 Then, as shown in Figure 3, these forces act on the compensator which deforms according to the dotted lines shown in the figure. It should be noted that the strong lines in this figure represent the equilibrium position, for example at room temperature.

As was recalled in the preamble to the present application, given the working conditions of these compensators and due to internal and external corrosion, these compensators have a reduced service life compared to the pipes forming the pipeline and short term there are leaks which are harmful to the environment and to the operation of the installation
In order to be able to repair such a defective pipe, it is then compulsory to physically cut it, to dismantle the expansion compensator in place then to replace this defective compensator with a new compensator of the same type.

 This intervention requires the shutdown of the installation and the prolonged shutdown of the latter.

 To overcome these drawbacks, the present invention provides a connection device (9) for pipe, the characteristic of which is that it is composed of at least two half-shells (10), (11) forming a sealing chamber part (12) and having, on the other hand, expandable means (13) in accordion or corrugated form.

 In addition, to avoid physically cutting the pipeline and to limit the time required for repair work, according to the invention, the two half-shells (10), (11) are able to be placed around said existing compensator ( 2) to replace it and to be joined together and on the pipeline (1).

FIG. 4 shows a first embodiment in which said half-shells (10) and (11) are obtained by forming a steel sheet, for example, and together define
- a cylindrical bearing surface (145 of a size suitable for surrounding the existing compensator (2),
- expansion means (13), in accordion or wavy form substantially constituted by at least one wave, arranged substantially in the extension of said cylindrical bearing (14),
- two lateral closing flanges (15) and (16), disposed respectively on either side of the cylindrical bearing surface (14) and of the expansion waves (13), these flanges being able to be crossed and secured to said pipe (1).

 In this first embodiment, when the half-shells (10), (11) are positioned on the pipe (1) at the level of the defective expansion compensator (2), these half-shells (10), (11) define a joint plane between them and with said pipe (1) in order to seal the connection. This tightness is reinforced by the actual joining by welding, for example.

 Figure 5 shows a second embodiment of the device of the present invention in which, unlike the embodiment of Figure 4 or the half-shells were formed in one piece, the latter consist of at least two parts.

More specifically, the half-shells (10), (11) are formed by:
- two cylindrical half-sleeves (17), (18),
- And two lateral flanges (19), (20) for closing the half-shells.

 Said cylindrical half-sleeves (17), (18) in particular obtained by forming, together define a cylindrical seat (21) of a size suitable for surrounding said existing compensator (2) and expandable means (22), in accordion or wavy, arranged substantially in the extension of said cylindrical seat (21).

 As regards the side flanges (19) and (20), each of them has on the one hand an internal orifice (23) capable of being traversed and secured on said pipe (1) and on the other hand a outer surface (24), capable of receiving and being secured to the two cylindrical half-sleeves (17), (18).

 As in the previous embodiment illustrated in Figure 4, said half-sleeves (17), (18) have a joint plane between them and with the outer surface (24) of each of the side flanges (19), (20 ) to seal the connection.

 In general, the various parts constituting the shells or sleeves of the device of the present invention will be made of sheet steel formed by any mechanical or hydraulic device known to those skilled in the art.

 As regards the expandable means, they may be, as the case may be and according to their determination criterion, constituted by one or more expansion waves also obtained by forming, arranged and distributed substantially in the extension of said cylindrical bearing.

 Figures 6 and 7 show a third more structured embodiment of the connection device (9) according to the present invention. This is an alternative embodiment of the two modes which have just been described above and there are the two half-shells (10), (11), the sealing chamber (12), the expandable means (13 ), the same cylindrical bearing surface (25) capable of surrounding the existing compensator, lateral closing flanges (26), (27).

 On the other hand, on this embodiment, various drain and purge orifices have been provided which will make it possible to evacuate the condensations which occur due to the leaks of the defective existing compensator (2).

 The various connection devices (9) for pipe which have just been described allow the pipe repair process of the present invention, by which an existing pipe is restored equipped with a defective expansion compensator (2) interposed between at least two sections of pipes (4), (5).

 For this, according to the invention, the defective expansion compensator (2) is left in place on the existing pipe (1) then there are at least two half-shells (10) around the said expansion compensator (2), ( 11) forming a sealing chamber (12) and expansion means (13).

 Then, said half-shells (10), (11) are joined in leaktight manner to each other and to said pipe (1) on either side of the defective expansion compensator (2).

 The half-shells will advantageously be joined by welding at their joint plane.

 This process may use the devices described with reference to FIGS. 4 to 7, however it should be noted that the production of the half-shells from cylindrical half-sleeves and separate closing side plates will be even more advantageous since this repair will not require any shutdown of the installation.

 In fact, when the half-shells are in one piece, as is the case in FIG. 4, when the half-shells are welded to the pipe, it will be necessary to cut off the circulation of gases in the pipe and allow it to cool. However, this downtime is negligible compared to the immobilization required during the complete replacement of the defective expansion compensator (2).

 On the other hand, in the case where the lateral flanges are separated from the sleeves, these lateral closing flanges (19), (20) will initially be placed on either side of each expansion compensator (2) at the time of constitution of the pipeline (1).

 Thus, when an expansion compensator (2) becomes defective, the pipe will be repaired by placing and securing the two half-sleeves (17) and (18) on said lateral flanges (19) and (20) .

 In this case, it should be noted that the joining by welding will be done at the bearing surfaces (24) of the closing flanges, welds which can be carried out without interrupting the circulation of the gas in the pipe or without reducing the pressure.

 However, the pipe (1) being repaired being hot and therefore the pipes being expanded, we will compress by pulling devices or other half-sleeves (17), (18) to adjust them to the length between flanges.

 Naturally, other implementations of the present invention could be envisaged without departing from the scope thereof. For example, one could envisage other configurations of the half-shells, other modes of joining together and on the pipe.

Claims (10)

 1. Connection device for pipes, such as in particular leaktight pipes, conveying hot fluids in steel plants, said pipe (1) having at least two sections of pipes (4), (5) between which a compensator of expansion (2), said connection device (9) being in particular intended for the repair of the existing pipeline at said expansion compensator (2), characterized by the fact that it is composed of at least two half -shells (10), (11), forming on the one hand sealing chamber (12) and having on the other hand expandable means (13) in accordion or corrugated, able to be placed around said existing compensator (2) to replace it and to be joined together and on the pipeline (1).  2. Connection device for pipe, according to claim 1, c a r a c t é r i sé in that said half-shells (10), (11) define together  a) a cylindrical seat (14) of a size suitable for surrounding said existing compensator (2),  b) expandable means (13) in accordion or wavy form, arranged substantially in the extension of said cylindrical seat (14),  c) two lateral closing flanges (15), (16) disposed respectively on either side of the cylindrical seat (14) and expandable means (13), capable of being crossed and secured on said pipe (1).  3. Connection device for pipe, according to claim 1, c a r a c t é r i sé in that said half-shells (10), (11) are constituted by  a) two cylindrical half-sleeves (17), (18) defining together  a cylindrical seat (21) of a size suitable for surrounding said existing compensator (2),  - expandable means (22) in accordion or wavy form, arranged substantially in the extension of said cylindrical seat (21),  b) two lateral closing flanges (19), (20) half-shells (10), (11) each having  - an internal orifice (23) capable of being crossed and secured to the pipe,  - An outer surface (24) capable of receiving and being secured to the two cylindrical half-sleeves (17), (18).  4. Connection device for pipe, according to claim 2, characterized in that said half-shells (10), (11) define a joint plane with each other and with said pipe (1) to ensure the tightness of the connection.  5. Connection device for pipe, according to claim 3, characterized in that said half-sleeves (17), (18) have a joint plane between them and with the outer surface (24) of each of lateral flanges (19), (20) in order to seal the connection.  6. Connection device for pipe, according to claim 2 or 3, characterized in that the expandable means (13) or (22) are constituted by one or more expansion zones obtained by forming arranged and distributed substantially in the extension of said cylindrical seat (14) or (21).  7. Connection device for pipe, according to claim 1, c a r a c t é r i sé in that it is made of sheet steel formed by a mechanical or hydraulic device.  8. Connection device for pipe, according to claim 1, c a r a c t é r i sé in that the half-shells (10), (11) are secured by welding at their joint plane.  9. A method of repairing a pipe, such as in particular sealed pipes conveying hot fluids in steel plants, said pipe (1) having at least two sections of pipes (4), (5) between which a expansion compensator is interposed. (2), said method using a connection device according to claim 1, characterized in that  - this defective expansion compensator (2) is left in place on the existing pipe (1),  - there are around said defective expansion compensator (2) at least two half-shells (10), (11) forming a sealing chamber (12) and expansion means (13),  - Said half-shells (10), (11) are joined in a leaktight manner to each other and to said pipe (1) on either side of said defective expansion compensator (2).  10. A method of repairing a pipe, according to claim 9, using a connection device according to claim 3, c a r a ct e r i s ed in that  - the lateral flanges (19), (20) are initially closed on either side of each expansion compensator (2) at the time of the constitution of the pipe (1),  - The two half-sleeves (17), (18) are placed on and secured to said lateral flanges (19), (20) when the original compensator becomes defective.