DEVICE FOR STOPPING A LEAKAGE FLOW ON A FLUID PIPELINE

Abstract

TITLE OF THE INVENTION: DEVICE FOR STOPPING A LEAKAGE FLOW ON A FLUID PIPELINE The device (30) for stopping excess flow of a leak on a fluid pipeline comprises: - a seal holder (39) having a tubular channel, - a plug (35) opposite the upstream end of the tubular channel, - an anchoring means (37) configured to anchor the seal holder in the predetermined pipeline, - a lip seal (40) that is leak-tight for the fluid flowing in the pipeline, elastically deformable up to a deployed configuration in which the radial extension of the lip seal is greater than the radial section of the predetermined pipeline, and - a retaining ring (41) for the lip seal, which has a cylindrical central part fixed relative to the seal holder and radial fins extending from the central part.At least one fin of the retaining ring, in its free radial deployment configuration, has a general planar shape of a symmetrical trapezoid whose base lies on the central portion, the free radial extension of the fins being equal to or greater than the radius of the predetermined pipe. Figure for the abbreviation: Figure 1.

Description

Title of the invention: DEVICE FOR STOPPING LEAKAGE FLOW ON A FLUID PIPELINE Technical field of the invention

[0001] The present invention relates to a device for stopping a leak in a fluid pipeline. It applies, in particular, to stopping the flow of a gas in the event of a leak in the pipeline downstream of the stop device. More specifically, the present invention applies to securing an existing natural gas delivery pipeline by inserting the stop device into this pipeline upstream of a gas meter. State of the art

[0002] Certain fluid distribution networks justify special safety measures, imposed by the nature of the fluid transported and by possible risks of damage to the pipes of which these networks are made up.

[0003] For example, gas distribution networks in urban areas generally extend under roads and sidewalks, that is to say under public domain structures that may be subject to various interventions, and in particular earthworks.

[0004] However, if a gas pipe is accidentally torn out or cut during such an operation, the resulting gas leak immediately presents a high risk of fire or explosion.

[0005] In this context, safety valves have been developed to shut off gas pipelines as soon as an abnormally high gas flow rate is detected. To date, however, safety valves can only be easily installed on new networks under construction, or possibly on existing networks, but only during their renovation. Indeed, since the pipelines of existing networks may have been built at different times and according to different standards, and their diameters may not necessarily be precisely defined, and they may exhibit obstacles, burrs, crushing, restrictions, and varying radii of curvature along their length, installing a safety valve in an existing network remains a delicate operation.The main difficulty stems from the need to carry out excavation to access the connection point and to create a pressurized seal to work on the connection when the gas is off. Summary of the invention

[0006] The invention aims to overcome all or part of the drawbacks of the prior art. A To this end, the present invention relates to an excess flow control device for stopping leakage flow in a fluid pipeline. This control device can be installed, without excavation, in most known fluid network pipelines, including pipelines with small radii of curvature, for example, on the order of ten times the diameter of the pipeline. The present invention also relates to a control device operating in circular pipes with a radius within a specified range, pipes that may be crushed and therefore have an elliptical cross-section, with the smaller and larger radii falling within this range. The present invention further relates to a device configured to be inserted into a pipeline along its wall, even if the wall has obstacles, burrs, restrictions, or bends.

[0007] The present invention relates to an excess flow control device for stopping a leakage flow on a predetermined fluid pipeline when this flow exceeds a predetermined value, this control device having an axis of rotational symmetry, this pipeline having a predetermined radius and an axis, characterized in that it comprises: - a seal holder comprising a tubular channel having upstream and downstream ends open to the passage of fluid, - a shutter opposite the upstream end of the tubular channel, retained by a return means in a first position away from the upstream end of the tubular channel, this shutter offering a surface on which a drag force is exerted by the fluid flow along this shutter in this first position, the return means being configured so that, when the flow rate is less than the predetermined value, the shutter remains in the first position and, when the flow rate is greater than the predetermined value, the shutter moves to a second position in which the shutter obstructs the upstream end of the tubular channel, the pressure difference between the upstream and downstream of the device which corresponds to this flow rate greater than the predetermined value then retaining the shutter in the second position, - an anchoring device configured to anchor the seal holder in the predetermined pipeline, - a lip seal that is leak-proof to the fluid flowing in the pipeline, elastically deformable up to a deployed configuration in which the radial extension of the lip seal is greater than the predetermined radial cross-section of the pipeline, this lip seal being hermetically fixed to the outer wall of the seal holder, such that the only fluid passing through the stop device flows inside the tubular channel, and - a lip seal retaining ring, which has a fixed cylindrical central part relative to the seal holder and radial fins extending from the central part, at least one said fin having, in its free radial deployment configuration, a general planar symmetrical trapezoidal shape whose base is on the central part, the free radial extension of the fins being equal to or greater than the radius of the predetermined pipe.

[0008] Thanks to these features, the device of the invention can be compact enough to be inserted, without excavation, into most known fluid network pipes, including pipes with small radii of curvature. The lip seal prevents fluid from escaping the tubular channel. Thanks to this lip seal, the device operates in circular pipes with a radius within a specified range, including pipes that may be compressed and therefore have an elliptical cross-section, with both the smaller and larger radii within this range. The radial extension of the retaining ring's fins provides a pressure force on the lip seal's lips against the inner wall of the protected pipe, ensuring a tight seal even under high pressure differences between the upstream and downstream sides of the device.

[0009] The free radial extension of the fins, equal to or greater than the radius of the predetermined pipe, ensures that the periphery of the lip seal is pressed against the inner wall of the pipe to be protected. In particular, the lip seal alone, for example made of elastomer, cannot ensure a good seal against pressurized fluid when the pipe diameter is not precisely defined, or when the pipe has an irregularity, burr, crushing, or restriction. The retaining ring and its radial fins ensure a better seal of the lip seal in all these cases.

[0010] Thus, thanks to the lip seal and the retaining ring, the device operates in pipes of circular cross-section having a radius within an extended radius range, pipes possibly crushed and consequently having an elliptical cross-section, whose small radius and large radius are within this extended radius range.

[0011] When the fluid flow rate is lower than the predetermined value, the obturator remains in a position where fluid flows through the tubular channel. However, when the fluid flow rate exceeds the predetermined value, particularly in the event of a significant leak downstream of the device, the obturator moves to a second position where it blocks the upstream end of the tubular channel, thus preventing fluid from flowing through the pipeline from upstream to downstream of the device. The anchoring means holds the device in position within the pipeline by means of the contact of the free end of each fin against the inner wall. of the pipeline.

[0012] In embodiments, the radial extension of at least one fin of the retaining ring, in the free radial deployment configuration, is between one percent and five percent greater than the predetermined radius of the pipeline.

[0013] This ratio allows the periphery of the lip seal to be pressurized against the inner wall of the pipe to be protected, even in the event of deformation of this wall resulting, for example, in an elliptical cross-section. This ratio, limited to five percent, also prevents the ends of the retaining ring fins from touching the inner wall of the pipe, which could damage it. This ratio, limited to five percent, also prevents the apex angle of the overall conical shape of the lip seal from being reduced, compared to the configuration of this seal outside the pipe, to the point that this conicity would be accompanied by folds on the surface of the lip seal.

[0014] In embodiments, the lip seal is fixed on the seal holder against an external annular stop of the seal holder and has an internal shoulder near this stop, such that, when this lip seal is in a folded configuration on the seal holder, this internal shoulder surrounds this external annular stop of the seal holder.

[0015] This internal shoulder allows the lip seal to be compressed in a configuration where its external surface is practically cylindrical, so that the fins of the retaining ring can bear on this cylindrical surface without undergoing irreversible deformation.

[0016] In embodiments, the lip seal has, in free configuration, a conical surface whose apex is on the downstream side of the lip seal, the retaining ring being positioned on the downstream side of the lip seal.

[0017] Thus, the retaining ring receives the lip seal bearing on its radial fins. Maintaining the conical shape of the lip seal is therefore ensured even when the pressure difference between the upstream and downstream sides of the device is high. Furthermore, an increase in this pressure causes an increase in the bearing force exerted by the periphery of the lip seal on the inner wall of the pipe.

[0018] In some embodiments, the retaining ring is crimped onto the seal holder. This type of fastening has the advantage of a reduced size and high mechanical resistance to pull-out.

[0019] In some embodiments, the thickness of the radial fins of the retaining ring, measured perpendicular to the surface of the lip seal, is less than 0.3 mm. The fins thus offer a good compromise between rigidity, to maintain the shape of the lip seal even in the event of a large pressure difference between the upstream and downstream sides of the device, and flexibility allowing the radial fins of the retaining ring to fold parallel to the outer wall of the seal holder.

[0020] In embodiments, the anchoring means in the pipeline comprises at least one fan washer having at least one elastically deformable fin having a fixed end relative to the seal holder and a free end subjected to an elastic restoring force towards a deployment configuration in contact with the inner wall of the fluid pipeline, in which this free end applies a static friction force on the inner wall of the fluid pipeline.

[0021] Each fan washer holds the device in position within the pipe, thanks to the contact of the free end of each fin against the inner wall of the pipe. Furthermore, this fan washer, together with the lip seal, ensures that the central axis of the device remains aligned with the central axis of the pipe.

[0022] In embodiments, the tubular channel of the seal holder has a diameter configured so that the pressure loss due to the presence of the stop device in the predetermined pipeline under a predetermined pressure is less than one quarter of this predetermined pressure.

[0023] This low pressure loss thus makes it possible to put two devices one behind the other in the pipeline in case the first one is defective. Brief description of the figures

[0024] Other advantages, purposes and features of the invention will become apparent from the following description, given for explanatory purposes and in no way limiting the effect of the accompanying drawings, in which:

[0025] [Fig-1] represents, in exploded perspective, components of an embodiment particular of a stopping device which is the subject of the invention,

[0026] [Fig.2] represents, in side view on its upper half and in cross-section on its lower half, the downstream part of a particular embodiment of a stopping device of the invention, in its radial deployment configuration bearing against the inner wall of a pipe of predetermined radius,

[0027] [Fig.3] represents, in side view on its upper half and in cross-section on its lower half, the downstream part of a variant of the stopping device illustrated in [Fig.2], in its radial deployment configuration supported on the inner wall of a pipe of predetermined radius,

[0028] [Fig.4] represents, in side view on its upper half and in cross-section on its lower half, the downstream part of a particular embodiment of a stop device of the invention, in its operating configuration before a leak occurs on the pipeline downstream of the stop device,

[0029] [Fig.5] represents, in side view for the left part and in section for the right part, a lip seal and a retaining ring of the downstream part of a particular embodiment of the stopping device which is the subject of the invention,

[0030] [Fig.6] shows, in side view for the left part and in cross-section for the right part, a lip seal and a retaining ring of the downstream part of a variant of the stopping device which is the subject of the invention,

[0031] [Fig.7] represents, in cross-sectional view, a seal holder of the downstream part of a particular embodiment of the stopping device which is the subject of the invention,

[0032] [Fig.8] represents, in side view, a fan washer of the downstream part of a particular embodiment of the stopping device which is the subject of the invention,

[0033] [Fig.9] represents, from a downstream perspective, the fan washer illustrated in [Fig.8],

[0034] [Fig. 10] shows, in side view, the fan washer illustrated in [Fig. 8], implanted within a pipe of predetermined radius,

[0035] [Fig. 11] shows, in side view, the fan washer illustrated in [Fig. 8] in its folded configuration for installation in a pipe,

[0036] [Fig. 12] represents, in side view, a variant of the fan washer illustrated in [Fig.8],

[0037] [Fig. 13] represents, from a downstream perspective, the fan washer illustrated in [Fig. 12],

[0038] [Fig. 14] represents, in side view, the fan washer illustrated in [Fig. 12], embedded in a pipe,

[0039] [Fig.15] shows, in side view, the fan washer illustrated in [Fig.12], in its folded configuration for implantation in a pipe,

[0040] [Fig. 16] represents, in side view, a shutter guide of the upstream part of a particular embodiment of the stopping device which is the subject of the invention,

[0041] [Fig. 17] represents, in cross-sectional view, the shutter guide illustrated in [Fig. 16],

[0042] [Fig. 18] represents, in perspective, a shutter seat of the stop device illustrated in [Fig. 1], and

[0043] [Fig. 19] represents, in the form of a flowchart, the manufacturing, configuration and installation steps of a stop device which is the subject of the invention in a pipeline. Description of the implementation methods

[0044] Throughout the description, the following terms are used: - “Upstream” refers to the direction from which the fluid that passes through the stopping device that is the subject of the invention originates. - “Downstream” refers to the direction in which the fluid flows through the stopping device that is the subject of the invention. - "Axis of the stopping device" or "central axis of the pipeline", an axis of symmetry by rotation of the stopping device or of the pipeline, which are generally confused, - "free radial deployment configuration", a configuration in which Each component of the stopping device extends radially according to its own internal mechanical constraints. - “radial deployment configuration in support”, a configuration in which each component of the arresting device extends radially according to its internal mechanical constraints and a support force exerted by an internal wall of a predetermined pipeline, - "Folded configuration", a configuration in which the elastically deformable components of the stop device are folded by an insertion sleeve and implantation of the stop device in the predetermined pipeline.

[0045] It should be noted from the outset that each of the figures is to scale, even if the scales of the different figures may be different, and - “radial” a direction perpendicular to the axis of the stopping device and passing through this axis.

[0046] Figure 1 shows the main components of a shut-off device 30 and an arrow indicating the direction of fluid flow from upstream, on the right, to downstream, on the left. Along the axis of rotational symmetry illustrated in Figure 1, the following components are observed successively from upstream to downstream: an inlet nozzle 31, a shut-off spring 33, a shut-off guide 32, a shut-off seat 34, a spacer 38, a seal holder 39, a lip seal 40, and a retaining ring 41. Outside this sequence are a movable shut-off 35, an O-ring 36, and a fan washer 37. The characteristics and interactions of these components are detailed with reference to the other figures. Their dimensions are adapted for installation and operation in a pipeline of predetermined radius, in which a predetermined fluid, for example a gas, flows under a predetermined pressure, for example four or six bar.

[0047] As illustrated in [Fig. 2], the downstream portion of the shut-off device 30 is built on the seal carrier 39. This seal carrier 39 comprises a tubular channel 398 having upstream and downstream ends open to the passage of fluid. This tubular channel 398 of the seal carrier 39 has a diameter configured so that the pressure drop due to the presence of the shut-off device 30 in the predetermined pipeline 25, under a minimum operating pressure, is less than one-quarter, and preferably one-sixth, of this minimum operating pressure. This low pressure drop thus makes it possible to place two devices 30 one after the other in the pipeline 25 in case the first one is defective.

[0048] This seal holder 39 carries an anchoring means configured to anchor the seal holder 39 in the predetermined pipeline 25. In the figures, a particular embodiment of this anchoring means consists of fan washers 37.

[0049] In [Fig.2], the downstream part is in a support deployment configuration, that is to say This illustrates the deployment of the fins of each fan washer 37, which rests against the inner wall of a pipe 25 with a predetermined radius. As will be described in more detail with reference to Figures 8 to 15, these fins then deploy in an intermediate configuration (see Figures 10 and 14) between a folded configuration (see Figures 11 and 15), where they are held by a tubular insertion sleeve (not shown) along the outer wall of the seal holder 39, and a free-deployment configuration (see Figures 8, 9, 10, and 13). Each fan washer 37 functions to center the seal holder 39 on the central axis of the pipe to be protected and to anchor the stop device 30 to the inner wall of this pipe.

[0050] In this particular embodiment comprising three fan washers 37, this downstream portion includes, bearing against the upstream side of a stop 394 on the external surface of the seal holder 39, a first spacer 38. A first fan washer 37 bears upstream on this first spacer 38. A second spacer 38 bears upstream on this first fan washer 37. A second fan washer 37 bears upstream on this second spacer 38. A third spacer 38 bears upstream on this second fan washer 37. Finally, a third fan washer 37 bears upstream on this third spacer 38. The spacers 38 serve to position the fan washers 37 at a distance from each other and with an angular offset between them.These two spacings, axial on the one hand and angular on the other, promote the folding of their elastic fins 371 along the external wall of the seal holder 39 in the introduction sleeve, before its implantation in the pipe to be protected.

[0051] At the downstream end of the seal holder 39, the lip seal 40 and the retaining ring 4L are fixed. At the upstream end of the seal holder 39, the shut-off seat 34 is fixed. The lip seal 40 has the function of closing the fluid flow over the entire radial section of the pipe to be protected except in the radial section of the seal holder 39. In other words, the fluid that passes through the shut-off device 30 travels through the internal volume of the seal holder 39. The lip seal 40 also has the function of centering the downstream end of the seal holder 39 on the central axis of the pipe. The retaining ring 41a has the function of stiffening the lip seal 40 and preventing it from turning around under the effect of overpressure in the pipe protected by the stop device, in particular when the movable obturator 35 comes to seal the upstream end of the seal holder 39, as explained below.

[0052] In the variant of the stop device 28 illustrated in [Fig. 3], the respective positions of the lip seal 40 and the retaining ring 41, on the one hand, and of the fan washers 37 and the spacers 38, on the other hand, are reversed. The seal holder 29 then presents a stop 394 on the external surface of its downstream end.

[0053] As illustrated in [Fig. 4], the upstream part of the stopping device 30 is made up of allow the movable shutter 35 to block the upstream end of the seal holder 39 in case of leakage downstream of the stop device 30.

[0054] The movable obturator 35 is located opposite the upstream end of the tubular channel 398. The movable obturator 35 is retained in the obturator guide 32 by a return means consisting of the spring 33, itself retained at its upstream end by a retaining ring 42 (not shown in [Fig. 1]). The movable obturator 35 is then in its initial position away from the upstream end of the tubular channel 398.

[0055] The movable obturator 35, equipped with the O-ring 36, offers a surface on which the fluid flow along this obturator 35 in this first position exerts a drag force.

[0056] The head 351 of the shutter 35 extends a movable body 353 in the shutter guide 32. This guide 32 includes a return means, in this example consisting of the spring 33.

[0057] The return means 33 is configured so that, when the flow rate inside the pipe is less than a predetermined value, the movable obturator 35 remains in its first position. Conversely, when the flow rate in this pipe is greater than the predetermined value, the movable obturator 35 moves and offers a larger bearing surface to the fluid. It continues its movement until it reaches a second position in which the head 351 of this movable obturator 35 obstructs the upstream end of the tubular channel 398. This predetermined value is reached, in particular, when there is a significant leak in the protected pipe downstream of the shut-off device 30. For example, the predetermined value corresponds to a pressure difference between the upstream and downstream ends of the shut-off device 30 equal to half the upstream pressure.

[0058] The head 351 of the shutter 35 has a through opening 352 from a face oriented towards the upstream end of the seal holder to a face oriented towards the shutter guide.

[0059] This through-hole 352 serves to automatically reset the device when the downstream leak is repaired. Resetting consists of the body of the movable shutter 35 returning to its position inside the shutter guide 32 when the pressure difference between the upstream and downstream sides of the device falls below a predetermined value that depends on the restoring force exerted by the restoring means 33. In some embodiments, the movable shutter 35 does not have this through-hole, and an increase in pressure downstream of the device must be manually performed by an operator to reset the device.

[0060] The pressure difference between the upstream and downstream sides of the shut-off device 30, which corresponds to this flow rate exceeding the predetermined value, then holds the shutter in the second position. In practice, the pressure difference between the upstream and downstream sides is much greater than this predetermined value because, when the movable shutter 35 is When closed, the downstream pressure is almost zero. As soon as this pressure difference returns to a value less than a second predetermined value, for example equal to the first predetermined value, the movable shutter 35 returns, under the effect of the return means 33, to its first position illustrated [Fig.4].

[0061] Figure 5 shows the lip seal 40 and the retaining ring 41. The lip seal 40 has a cylindrical peripheral portion 401 with a diameter equal to or slightly larger (for example, one to five percent larger) than the nominal diameter of the pipe to be protected. The lip seal 40 also has a cylindrical central portion 403 with a diameter equal to or smaller (for example, one to five percent smaller) than the diameter of the seal holder 39. The central portion 403 of the lip seal 40 is fixed in a watertight manner to the outer wall of the tubular channel 398. The lip seal 40 also has a conical portion 402 connecting the peripheral portion 401 and the central portion 403.

[0062] The lip seal 40 is fixed to the seal holder 39, which has the tubular channel 398 abutting the external annular stop 392 of the annular channel. The lip seal 40 has an internal shoulder 404 near this stop 392, such that, when this lip seal 40 is in a folded configuration (not shown) on the seal holder 39, this internal shoulder 404 surrounds this external annular stop 392. This internal shoulder 404 allows the lip seal 40 to be compressed into a configuration where its external surface is practically cylindrical, so that the fins 412 of the retaining ring 41 can bear against this cylindrical surface without undergoing irreversible deformation. The deployment of the lip seal 40 therefore takes place without deformation of the fins 412 after the positioning of the device 30 in this pipe 25. In [Fig.[5] The shoulder 404 has a flat, ring-shaped surface which bears against the stop 392 and extends radially beyond it, so that the thickness of the lip seal 40 is reduced at the end of this flat ring. A second part of the shoulder 404 is conical and joins the internal conical surface of the upstream face of the lip seal 40.

[0063] The material constituting parts 401, 402, and 403 is elastically deformable from a folded configuration along the outer wall of the seal holder 39 to a free radial deployment configuration in which the radial extension of the lip seal is greater than the radial cross-section of the predetermined pipe 25. For example, the radius of part 401, measured from the axis of rotational symmetry of the stop device 30, is between one percent and five percent greater than the predetermined radius of the pipe 25. The peripheral part 401 is pressed tightly against the inner wall of the pipe 25. Consequently, the only fluid passing through the stop device 30 flows within the tubular channel 398 of the seal holder 39.

[0064] The retaining ring 41 has a cylindrical central portion 411 configured so that the downstream end of the seal holder 39 is crimped onto this central portion 411. It also has radial fins 412 extending from the central portion 411.

[0065] In [Fig.6], a variant of the lip seal 40 is observed, in which the internal shoulder 405 of the lip seal 40 has a conical part extending from the upstream internal surface of the lip seal 40 and a part forming a circular ring bearing against the stop 392 of the seal holder 39.

[0066] At least one of the radial fins 412 has, in its free radial deployment configuration, a general planar symmetrical trapezoidal shape, the base of which is located on the central part 411. The radial extension of the fins 412 is, in the free radial deployment configuration, equal to or greater than the radius of the predetermined pipeline 25. For example, the radial extension of the fins 412 is, in this configuration, equal to or greater (for example, one to five percent greater) than the radius of the pipeline 25 to be protected.

[0067] The free radial extension of the fins 412, equal to or greater than the predetermined radius of the pipe 25, ensures that the periphery of the lip seal 40 bears against the inner wall of the pipe 25 to be protected. In particular, the lip seal 40 alone, for example made of elastomeric material, cannot provide a good seal against pressurized fluid when the diameter of the pipe 25 is not precisely defined, or when the pipe has an irregularity, burr, crushing, or restriction. The retaining ring and its radial fins ensure a better seal of the lip seal in all these cases.

[0068] Thus, thanks to the lip seal 40 and the retaining ring 41, the device 30 operates in pipes 25 of circular cross-section having a radius within an extended radius range, pipes possibly crushed and consequently having an elliptical cross-section, the small radius and the large radius of which are within this extended radius range.

[0069] In embodiments, the radial extension of at least one fin 412 of the retaining ring 41, in the free radial deployment configuration, is between one percent and five percent greater than the predetermined radius of the pipe 25. The bearing force of the periphery of the lip seal 40 on the inner wall of the pipe 25 is thus particularly high, and ensures a high seal of the junction of the lip seal 40 on the inner wall of the pipe 25.

[0070] In the embodiments shown in Figures 5 and 6, the lip seal 40, in its free configuration, has a conical surface whose apex is on the downstream side of the lip seal 40, the retaining ring 41 being positioned on the downstream side of the lip seal. Thus, the retaining ring 41 receives the lip seal 40 bearing on its radial fins 412. The maintenance of the conical shape of the lip seal 40 is thus ensured even when the pressure difference is high between the upstream and downstream of the device 30. In addition, thanks to the orientation of the conical shape of the lip seal 40 and the fins 412, an increase in this pressure causes an increase in the support force of the periphery of the lip seal 40 on the internal wall of the pipe 25.

[0071] In some embodiments, the retaining ring 41 is crimped onto the seal holder 39 comprising the tubular channel 398. This type of fixing has the advantage of a reduced size and high mechanical resistance to pull-out.

[0072] Preferably, the thickness of the radial fins 412 of the retaining ring 41, measured perpendicular to the conical surface of the lip seal 40, is less than 0.3 mm. The fins 412 thus offer a good compromise between rigidity, to maintain the shape of the lip seal even in the event of a large pressure difference between the upstream and downstream sides of the device, and flexibility allowing the radial fins of the retaining ring to fold parallel to the outer wall of the tubular channel.

[0073] It is noted that, preferably, the fins 412 of the retaining ring 41 are connected to the lip seal 40 in such a way that they do not touch the inner wall of the pipe 25. In other words, the lip seal 40 extends radially beyond its connection with the end of the fins 412. This geometric feature ensures that it is the only lip seal 40 that bears against the inner wall of the pipe 25 and thus ensures the sealing of its connection with this pipe 25.

[0074] The gasket holder 39 illustrated in [Fig.7] has a generally cylindrical shape with di circular guide perpendicular to the axis of the stopping device. The interior of this seal holder 39 constitutes the tubular channel 398 for the passage of the fluid. On the outer wall of this seal holder 39, from upstream to downstream, we observe the annular stop 394, which retains each fan washer 37 and each spacer 38. And an annular stop 392, similar to the annular stop 394, which retains the lip seal 40 and the retaining ring 4L. A zone 393 is located between the annular stops 392 and 394. The length of zone 393, measured parallel to the axis of the stop device, is such that the wings 371 of the fan washers 37 and the lip seal 40 do not touch when they are folded along the outer wall of the seal holder 39, for insertion into the pipe to be protected. In other words, the sum: - the length of the conical part 402 of the lip seal 40, measured along its surface in a section of the lip seal by a plane passing through the axis of the retaining device 30, - the length of the cylindrical part 401 of the lip seal 40, measured parallel to the axis of the stop device 30 and - the length, measured parallel to the axis of the stopping device 30, of the fins 371 in their folded configuration (see figures 11 and 15) is greater than the sum: - of the length of zone 393, - the length of the two annular stops 392 and 394, measured parallel to the axis of the stop device 30, and - the length of a spacer 38, measured parallel to the axis of the stop device 30.

[0075] A part 391 of the seal holder 39 is deformed during crimping to fix the seal 40 and its retaining ring 41 onto the seal holder 39.

[0076] A chamfer 396 inside the seal holder 39 extends the slope of the obturator seat 34 so as not to create a step for the flow and thus limit pressure losses.

[0077] An additional thickness 397, internal to the seal holder 39, allows to give a little thickness to the wall of the seal holder 39 to compensate for the material lost by the thread allowing the junction between this seal holder 39 and the obturator seat 34.

[0078] Figures 8 and 9 show a fan washer 37, which has a central annular part 373 fixed to the seal holder 39 and fins 371 extending in a star shape from the fixed part 373.

[0079] Each fin 371 is elastically deformable and has a fixed end relative to the tubular channel 398 of the seal holder 39 and a free end 372 subjected to an internal elastic restoring force towards a deployment configuration in contact with the inner wall of the fluid channel. In this radial deployment configuration, this free end 372 applies a static friction force to the inner wall of the fluid channel 25. As shown opposite [Fig. 19], at least one fin 371 is obtained by annealing after being formed into the free radial deployment configuration.

[0080] Since this fan washer 37 is made by cutting and then bending a flat metal plate, which reduces the elasticity of the fan washer, annealing each fin 371 gives the fin 371 shape memory, increasing the contact area of ​​the fin 371 with the inner wall of the pipe. Furthermore, to insert the device 30 into the pipe 25 without excavation, it is necessary to compress each fin 371 of a fan washer 37 towards the axis of the device 30. This compression allows the device 30 to move inside the pipe 25 before it is installed, even if the inner wall of this pipe 25 has obstacles, burrs, restrictions, or bends. However, this compression could cause irreversible deformation of the fin 371 if it were not annealed.However, a reduction in the support of the end of the fin 371 on the inner wall of the pipe 25 means a reduction in the static friction force exerted by this wall on the fin 371 to hold the device 30 in position.

[0081] For example, the fan washer 37 is made of austenitic stainless steel alloy chromium (18%) and nickel (8%), referenced "X10 Cr Ni 18.8".

[0082] Each fin 371 has a "T" shape at its free end 372 due to the presence of shoulders 376. The width of the fins 371, measured perpendicular to a plane passing through the axis of the retaining device 30, decreases linearly from their base on the fixed part 373 to the shoulders 376, and then increases from these shoulders 376. This trapezoidal shape, visible in [Fig. 9], from the base to the shoulders 376, limits the bulk of the fins 371 of one fan washer 37 on another fan washer 37. Preferably, these fins 371 of two successive fan washers 37 do not overlap when the fins 371 are in the folded configuration, thanks to an angular offset between the successive fan washers 37. This angular offset, relative to the axis of the stopping device 30, is ensured by lugs (not shown) which fit into notches 377 of the fixed part 373.These offset lugs are located on the upstream and downstream faces of the spacers 38. The angular offset is equal to one turn divided by twice the number of fins 371 per fan washer 37 (i.e., 18 degrees for 10 fins). For example, in Figures 2 and 3, it can be seen that the intermediate fan washer 37 is angularly offset relative to the upstream and downstream fan washers 37.

[0083] When free from any external constraint, as in the free radial deployment configuration illustrated in [Fig. 8], each fin 371 extends, in a plane passing through the axis of rotational symmetry of the stopping device 30 (the plane of [Fig. 8]), and has, from its base in contact with the fixed part 373 to its end 372, a radius of curvature 374A and then 375A. This part having a radius of curvature extends, in the embodiment shown in [Fig. 8], to the shoulders 376 from which the end 372 of the fin 371 begins. This radius of curvature 374A, 375A, varies by a multiplicative factor of less than two, that is to say, the ratio of its maximum value 375A to its minimum value 374A is less than two. Of course, the radius of curvature varies preferentially progressively from its minimum value of 374A to its maximum value of 375A.

[0084] Thanks to its curvature, 374A and 375A, the fin 371 does not have a bend over a significant portion, or even over its entire length. Therefore, the fin 371 does not have a weak point due to a bend. Furthermore, the curvature 374A and 375A of the fin 371 ensures that the angle formed between the tip of the fin 371 and the inner wall of the pipe 25, at their point of contact, is greater than if the fin were straight. The greater this angle, the more effective the anchoring of the tip of the fin 371 against the inner wall of the pipe.

[0085] Thus, in the event of a simultaneous occurrence of a sudden leak on the pipe 25 downstream of the device 30 and an overpressure upstream, during the closing of the obturator, the "water hammer" caused by this closure cannot lead to a re bending of the fins 371 which would result in this device 30 detaching from the wall of the pipe 25 and no longer performing its function of sealing this pipe 25.

[0086] In embodiments such as those shown in Figures 8 and 12, in its free radial deployment configuration, the radius of curvature 374A, 375A, 374B, 375B of at least one fin 371 is an increasing function of the distance to the axis of the device 30. The growth of the radius of curvature of the fin 371 as a function of the distance to the axis of the device 30 ensures that the resistance of each part of the fin 371 to bending increases with the moment of the static friction force exerted by the inner wall of the pipe 25 on that part of the fin 371. The retention capacity of the device 30 in the pipe 25 is thus reinforced.

[0087] In some embodiments, in its free radial deployment configuration, the radius of curvature 374A, 375A, 374B, 375B of at least one fin 371 is a decreasing function of the width of the fin 371, measured perpendicular to the plane passing through the axis of rotational symmetry of the retaining device 30. The decrease in the width of the fin 371 as a function of the distance from the axis of the device 30 ensures that the bending resistance of each part of the fin 371 increases with the moment of the static friction force exerted by the inner wall of the pipe 25 on that part of the fin. The retention capacity of the device 30 in the pipe 25 is thus enhanced.

[0088] In embodiments, in a radial deployment configuration with the free end of at least one fin 371 supported on the inner wall of the predetermined pipeline 25, the acute angle 379 between the tangent to the free end 372 of the fin 371 in said plane passing through the axis of rotational symmetry of the stopping device 30 with the wall of the pipeline 25, is greater than 25 degrees (see figures 10 and 14).

[0089] As explained above, this angle 379 is sufficiently high so that the anchoring of the end of the fin 371 against the inner wall of the pipe 25 is effective, even in the event of a large pressure difference between the upstream and downstream sides of the device 30.

[0090] The centers of curvature corresponding to the radii of curvature 375A, 374B and 375B are located further from the axis of rotational symmetry of the stop device 30 than the free end 372 of the fin 371, in its free radial deployment configuration. The fins 371 thus exhibit a curvature outwards from the device 30 but remain oriented downstream of the device 30, even at their free end 372. This curvature makes it possible to increase the angle of incidence of the free ends 372 on the inner wall of the protected pipe 25, as illustrated in [Fig. 10]. Preferably, the radius of curvature, 374A, 375A, 374B, and 375B, of each fin 371 is an increasing function of the distance to the base of the fins 371. Preferably, the radius of curvature, 374A, 375A, 374B and 375B, of at least one fin 371 is, in this part extending from the base of the fin to the shoulders 376, a decreasing function of the width of the fin 371, this width being measured perpendicular to the plane passing through the axis of rotational symmetry of the stopping device 30.

[0091] In the example shown in [Fig. 8], the successive bends, moving away from the fixed part 373, successively have two centers located in a plane passing through the fixed part 373. Furthermore, the two radii of curvature, 374A and 375A, have two values ​​whose ratio of the larger to the smaller is less than two and, preferably, less than 1.75. For example, the smaller radius of curvature 374A, near the base of the fins 371, measures between one-sixth and one-third of the inside diameter of the protected pipe 25, typically between one-fifth and one-quarter of this diameter. For example, the larger radius of curvature, 375A, near the shoulders 376, measures between one-quarter and one-half of the inside diameter of the protected pipe 35, typically one-third of this diameter.The radius of curvature, 374A and 375A, of the fins 371 is thus decreasing with the distance to the free end 372 which is in static friction against the inner wall of the protected pipe 25. The inventors determined that this decrease as a function of the lever arm exerted by this static friction on the fin 371 ensured better flexibility, i.e. capacity for temporary deformation, and therefore better resistance to overpressures which may occur at the level of the stop device 30, in particular when the movable obturator 35 obstructs the upstream end of the tubular channel 398 of the seal holder 39.

[0092] Preferably, in its free radial deployment configuration, the distance between the free end 372 of at least one fin 371 and the axis of rotational symmetry of the stop device 30 is greater by at least 15% than the predetermined radius of the predetermined pipeline 25. Such a compression factor of each fin 371 once the device 30 is placed in the pipeline 25 ensures a static friction force of the inner wall on the end of the fin 372 sufficient for the device 30 to remain in place even in the event of a large pressure difference between the upstream and downstream sides of the device 30.

[0093] It is observed, in [Fig. 10], that, due to the radial compression of the fins 371, each of their free ends 372 exerts a support force perpendicular to the central axis of the pipe 25 on the internal wall of this pipe 25. Now, the static friction forces are proportional to these radial support forces.

[0094] Preferably, each distal contact surface 378 of the free ends 372 of the fins 371 is curved and configured to be tangent, along its entire length, to the inner wall of a pipe 25 of predetermined diameter. This avoids the risk of scratching the inner wall of the pipe 25, since it increases the surface area of contact.

[0095] As illustrated in [Fig. 10], in a radial deployment configuration with the free end 372 of at least one fin 371 supported on the inner wall of the predetermined pipeline 25, the acute angle between the tangent to the fin 371 in the plane passing through the axis of rotational symmetry of the stopping device 30 and the wall of this pipeline is preferably greater than 25 degrees.

[0096] The variant of the fan washer 37 illustrated in figures 12 to 15 has the same characteristics as the fan washer 37 illustrated in figures 8 to 11, except that the radius of curvature 374B of the fin 371, the smallest near the base of the fins 371, is between 30% and 40% of the internal diameter of the pipe to be protected, typically one third, and that the radius of curvature, 375B, near the shoulders 376, is between 40% and 60% of this diameter, typically half.

[0097] Figures 16 and 17 show a guide 32 for a shutter 35. This guide 32 has an upstream cylindrical external surface 321, followed by a toroidal surface 322, and then a conical surface 323. This conical surface 323 constitutes all or part of a fluid flow deflector configured to reduce the drag force exerted by the fluid on the head of the shutter. This deflector limits the entrainment of the movable shutter 35 by the fluid flow when the shutter 35 is in its first position described above with reference to [Fig. 4]. Furthermore, thanks to this deflector 323, the fluid pressure loss due to the presence of the shut-off device 30 in the protected pipeline is reduced as long as the movable shutter 35 has not been triggered. On the downstream side, the guide 32 ends with a threaded cylindrical surface 324 for assembly with the obturator seat 34.

[0098] The fluid flow deflector reduces both the pressure loss between the upstream and downstream of the device 30, when the shutter 35 is open and the instability of this shutter 35 which could be caused by turbulence near its head 351.

[0099] A groove 325 allows for a through thread 324. The shutter seat 34 can thus be screwed and tightened onto the shutter guide 32 bearing against the shoulder 326, a through thread 341 of the shutter seat 34 also being a through thread.

[0100] The shutter seat 34 illustrated in [Fig. 18] has a threaded upstream opening 341 configured to assemble onto the threaded surface 324 of the guide 32. The shutter seat 34 has, on its outer surface surrounding the opening 341, a conical surface 342 extending from the conical surface 323 of the guide 32, when the guide 32 and the shutter seat 34 are assembled, as illustrated in [Fig. 4]. This conical surface 342 constitutes all or part of a flow deflector configured to reduce the drag force exerted by the fluid on the head 351 of the shutter 35.

[0101] Alternatively, only the shutter guide 32 or only the shutter seat 34 has a deflector. Thus, according to some embodiments, the shutter seat and / or the guide have, on their outer surface, a flow deflector configured to reduce the drag force exerted by the fluid on the shutter head.

[0102] Preferably, however, the flow deflector is carried by the shutter guide and by the shutter seat. In the example shown, the deflector has a conical shape whose apex is located in the shutter guide.

[0103] In this example, the apex angle 327 (see [Fig. 4]) of the conical shape of the deflector is between 20 degrees and 40 degrees. The inventor has determined that these values ​​of angle 327 prevent the occurrence of turbulence detrimental to the operational stability of the obturator 35, while ensuring a low pressure drop due to the device 30. This low pressure drop thus makes it possible to place two devices 30 one after the other in the pipe 25, in case the first one is defective.

[0104] This fluid flow deflector has, in the example shown, a maximum diameter greater than three-quarters of the diameter of the seal 36 of the obturator 35. A drag force is thus maintained on the head 351 of the obturator 35 which carries this seal 36, in order to cause, when the flow rate is greater than the predetermined value, the displacement of the obturator 35 to its second position in which the head 351 and the seal 36 of the obturator 35 obstruct the upstream end of the tubular channel 398.

[0105] The conical surface 342 has the same angle and functions as the conical surface 323. Downstream of the conical surface 342, the obturator seat 34 has three lateral openings 343 that allow the fluid to pass towards the upstream end of the seal holder 39. Three arches 344 separate these three lateral openings 343. The upstream faces 346 of the arches 344 extend, at a different apex angle, the conical surface 342 and help to limit the drag force exerted by the fluid on the head 351 and the seal 36 of the obturator 35. These arches 344 reduce the risk of turbulence occurring in the fluid flow surrounding the device 30. Finally, the obturator seat 34 has a downstream ring 345 configured to be screwed around the upstream end of the seal holder 39.

[0106] Figure 19 shows steps in a process 50 for manufacturing and installing the stop device 30 in a pipeline 25 to be protected. In a step 51, the various parts of the device 30 are manufactured, with all or part of the technical characteristics described above. Preferably, during the manufacture of the fan washers 37, they are annealed.

[0107] Annealing brings alloys into physico-chemical and mechanical equilibrium. It tends to achieve structural equilibrium by eliminating non-equilibrium states resulting from previous heat and mechanical treatments. Annealing corresponds to the values maximum ductility characteristics (resilience and elongation) and minimum values ​​of resistance characteristics (hardness, yield strength, breaking load).

[0108] The thermal cycle of an annealing carried out during step 51 comprises: - heating to a temperature known as the "annealing temperature," which depends on the type of annealing to be carried out. - isothermal maintenance at the annealing temperature or oscillations around this temperature, - very slow cooling generally in still air, the cooling rate being less than the critical annealing rate.

[0109] The annealing performed during step 51 involves heating and holding at (AC3 + 50 °C, where AC3 refers to the alpha / gamma transformation temperature in a steel, determined by heating at a rate of 150 to 300 °C / hour) followed by furnace cooling to low degrees of supercooling to ensure the decomposition of austenite and prevent the formation of high-hardness structures (martensite, bainite). This annealing is carried out on parts that have undergone various heat and mechanical treatments to facilitate their machining or cold forming.

[0110] Alternatively, annealing requires temperatures below AC1, the eutectoid transformation temperature, particularly softening annealing and coalescence annealing. Softening annealing is an annealing process carried out at a few tens of degrees below AC1 (650-680°C) followed by slow cooling to obtain a sufficiently stable and, if possible, stress-free state. This treatment aims to improve machinability or cold-formability. For high-alloy steels, it is the only treatment that destroys non-equilibrium structures and reduces hardness.

[0111] Alternatively, coalescence (or globalization) annealing is used to improve the cold-forming ability of steel, generally aiming to obtain a globular cementite structure. This annealing improves the machinability of steels by enabling the application of high cutting speeds and ensuring a very good surface finish. The thermal cycle comprises: - a heater just below temperature AC1, - prolonged maintenance at this temperature, or oscillation around it, - slow cooling to obtain the coalescence of the cementite.

[0112] In step 52, the parts of the stop device 30 are assembled as described above. In step 53, the lip seal 40, the retaining ring 41, and the fins 371 of the fan washer 37 are compressed toward the axis of the device 30 to achieve a folded configuration. In step 54, the device thus The folded device is inserted into a cylindrical sleeve (not shown). In this folded configuration, the device 30 can move within a pipeline and follow its curves without damaging either the device or the pipeline. During step 55, a housing (not shown) is assembled onto the pipeline to be protected 25 at the customer's control box.

[0113] In step 56, a rod is assembled to the sleeve, and the stop device 30 is inserted into the pipe 25 with this rod. In step 57, the device 30 is positioned back from a fork in the pipe to be protected 25, for example, a fork connecting the pipe to be protected 25 to a larger supply pipe. In step 58, the device 30 is removed from the sleeve by applying pressure to the rod to which the sleeve is attached. The lip seal 40, the retaining ring 41 and the fins of the fan washer 37 then partially deploy to bear against the inner wall of the pipe 25. During a step 59, the stop device 30 is tested by abruptly reducing the pressure downstream of this device and verifying that the obturator 35 has triggered and obturated the tubular channel 398 of the seal holder 39.The shutter 35 is then re-engaged by restoring the pressure downstream of the device 30.

Claims

1. Demands Excess flow control device (30) for stopping a leakage flow on a predetermined fluid pipeline (25) when this flow exceeds a predetermined value, this control device having an axis of rotational symmetry, this pipeline having a predetermined radius and an axis, characterized in that it comprises: - a seal holder (39) comprising a tubular channel (398) having upstream and downstream ends open to the passage of fluid, - a plug (35) opposite the upstream end of the tubular channel, retained by a return means (33) in a first position away from the upstream end of the tubular channel, this plug providing a surface on which a drag force is exerted by the fluid flow along this plug in this first position, the return means being configured so that, when the flow rate is less than the predetermined value, the plug remains in the first position and, when the flow rate is greater than the predetermined value, the plug moves to a second position in which the plug obstructs the upstream end of the tubular channel, the pressure difference between the upstream and downstream ends of the device corresponding to this flow rate greater than the predetermined value then retaining the plug in the second position, and - an anchoring means (37) configured to anchor the seal holder in the predetermined pipe, - a lip seal (40) that is leak-proof against the fluid flowing in the pipeline, elastically deformable up to a deployed configuration in which the radial extension of the lip seal is greater than the predetermined radial section of the pipeline, this lip seal being hermetically fixed to the outer wall of the seal holder, such that the only fluid passing through the stop device flows within the tubular channel, and - a retaining ring (41) of the lip seal, which has a cylindrical central part (411) fixed relative to the seal holder and radial fins (412) extending from the central part, at least one said fin having, in its free radial deployment configuration, a general planar symmetrical trapezoidal shape whose base is on the central part, the free radial extension of the fins being equal to or greater than the radius of the predetermined pipe.

2. Stop device (30) according to claim 1, wherein the radial extension of at least one fin (412) of the retaining ring (41), is, in the free radial deployment configuration, between one percent and five percent greater than the predetermined radius of the pipe (25).

3. Stop device (30) according to any one of claims 1 or 2, wherein the lip seal (40) is fixed on the seal holder (39) abutting an external annular stop (392) of the seal holder and has an internal shoulder (404) near this stop, such that, when this lip seal is in a folded configuration on the seal holder, this internal shoulder surrounds this external annular stop of the seal holder.

4. Stop device (30) according to any one of claims 1 to 3, wherein the lip seal (40) has, in free configuration, a conical surface whose apex is on the downstream side of the lip seal, the retaining ring (41) being positioned on the downstream side of the lip seal.

5. Stop device (30) according to any one of claims 1 to 4, wherein the retaining ring (41) is crimped onto the seal holder (39).

6. Stop device (30) according to any one of claims 1 to 5, wherein the thickness of the radial fins (412) of the retaining ring (41), measured perpendicular to the surface of the lip seal (40), is less than 0.3 mm.

7. Stop device (30) according to any one of claims 1 to 6, wherein the anchoring means (37) in the pipeline (25) comprises at least one fan washer having at least one elastically deformable fin (371) having a fixed end relative to the seal holder (39) and a free end (372) subjected to an elastic restoring force towards a deployment configuration in contact with the inner wall of the pipeline, wherein this free end applies a static friction force on the inner wall of the pipeline.

8. Stop device (30) according to any one of claims 1 to 7, wherein the tubular channel (398) of the seal holder (39) has a diameter configured so that the pressure loss due to the presence of the stop device in the predetermined pipeline (25) under a predetermined pressure is less than one quarter of that predetermined pressure.

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