Device for stopping a leakage flow on a fluid pipe

Abstract

The device (30) for stopping the excess flow of a leak on a fluid pipe comprises: a seal carrier (39) comprising a tubular channel, a fluidtight lip seal (40), a plug (35) facing the upstream end of the tubular channel, and at least one externally-toothed washer (37) comprising at least one elastically deformable fin having one fixed end, fixed relative to the seal carrier, and one free end subjected to an elastic return force towards a configuration of deployment in contact with the inner wall of the fluid pipe, in which configuration this free end applies a static friction force to the inner wall of the fluid pipe. At least one fin (37) extends, in its free radial deployment configuration, in a plane passing through the axis of symmetry of rotation of the stop device, and has, from its base to its end, a radius of curvature which varies by a factor of less than three and preferably than two.

Description

[0001] DESCRIPTION

[0002] DEVICE FOR STOPPING A LEAK FLOW ON A FLUID PIPELINE

[0003] TECHNICAL FIELD OF THE INVENTION

[0004] The present invention relates to a device for stopping a leak flow on a fluid pipe. It applies, in particular, to stopping the flow of a gas in the event of a leak in the pipe downstream of the stopping device. More particularly, the present invention applies to securing an already installed natural gas delivery pipe, by inserting the stopping device into this pipe upstream of a gas meter.

[0005] STATE OF THE ART

[0006] Certain fluid distribution networks require 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.

[0007] For example, gas distribution networks in urban areas generally extend under roads and sidewalks, that is to say under public works likely to be subject to various interventions, including earthworks.

[0008] However, if a gas pipe is accidentally torn off or severed during such an operation, the resulting gas leak immediately poses a high risk of fire or explosion.

[0009] In this context, safety valves have been developed to close gas pipes as soon as an abnormally high gas flow 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 pipes in existing networks may have been built at different times and according to different standards, where they do not necessarily have diameters defined with great precision, and where they have obstacles, burrs, crushing, restrictions, and varied radii of curvature along their length, the installation of a safety valve in an existing network remains a delicate operation.The main difficulty comes from the need to carry out earthworks to access the connection socket and to carry out a load seal to work on the connection outside the gas supply.

[0010] Document WQ2008 / 145939 is known, which describes a safety device for controlling the flow of a fluid in a pipeline. This device has straight elastic lateral claws which, once released from radial compression, extend to the internal wall of the pipeline. This device presents risks of sliding on this internal wall under the effect of the pressure of the fluid.

[0011] SUMMARY OF THE INVENTION The invention aims to overcome all or part of the drawbacks of the prior art. To this end, the present invention provides an excess flow stop device for stopping a leakage flow on a fluid pipe. This stop device can be installed, without excavation, in most pipes of known fluid networks, including in pipes having small radii of curvature, for example of the order of ten times the diameter of this pipe. The present invention also aims at a stop device operating in pipes of circular section having a radius lying within a range of radii, pipes possibly crushed and consequently having an elliptical section, the small radius and the large radius of which lie within this range of radii.The present invention also relates to a device configured to be inserted into a pipe along its wall, even if the latter has obstacles, burrs, restrictions or bends.

[0012] The present invention relates to an excess flow stop device for stopping a leakage flow on a predetermined fluid pipe when this flow exceeds a predetermined value, this stop device having an axis of rotational symmetry, this pipe having a predetermined radius and an axis, device which comprises:

[0013] - a seal holder comprising a tubular channel having upstream and downstream ends open to the passage of fluid,

[0014] - a lip seal which is impervious to the fluid circulating in the pipeline, elastically deformable to a deployed configuration in which the radial extension of the lip seal is greater than the predetermined radius of the pipeline, this lip seal being fixed in a sealed manner to the external wall of the seal holder, in such a way that the only fluid passing through the stop device circulates inside the tubular channel,

[0015] - a shutter facing the upstream end of the tubular channel, retained by a return means in a first position remote from the upstream end of the tubular channel, this shutter providing a surface on which a drag force is exerted by the flow of fluid along this shutter in this first position, the return means being configured so that, when the flow rate is lower than the predetermined value, the shutter remains in the first position and, when the flow rate is higher 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 higher than the predetermined value then retaining the shutter in the second position, and

[0016] - at least one fan washer comprising at least one elastically deformable fin having a fixed end relative to the seal holder and a free end subjected to an elastic return force towards a deployment configuration in contact with the internal wall of the fluid pipe, in which this free end applies a static friction force on the internal wall of the fluid pipe, at least one fin extends, in its free radial deployment configuration, in a plane passing through the axis of rotational symmetry of the stop device, and has, from its base to its end, a radius of curvature which varies by a factor of less than three.

[0017] Preferably this factor is less than two.

[0018] Thanks to these provisions, the device which is the subject 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 the fluid from passing outside the tubular channel. Thanks to this lip seal, the device operates in pipes with a circular section having a radius within a range of radii, pipes which may be crushed and therefore have an elliptical section, the small radius and the large radius of which are within this range of radii.

[0019] When the fluid flow rate is lower than the predetermined value, the shutter remains in the position in which the fluid passes through the tubular channel. However, when the fluid flow rate becomes higher than the predetermined value, particularly in the event of a significant leak downstream of the device, the shutter moves to a second position in which the shutter blocks the upstream end of the tubular channel, thus preventing the fluid from passing through the pipe from upstream to downstream of the device. Each fan washer holds the device in position in the pipe, thanks to the contact of the free end of each fin against the internal wall of the pipe.

[0020] Thanks to the radius of curvature of the fin, which varies by a factor of less than three and preferably less than two, the fin does not have a bend over its entire extension. The fin therefore does not have a weak zone due to a bend. In addition, the curvature of the fin allows the angle formed between the end of the fin and the internal wall of the pipe at their point of contact to be greater than if the fin were straight. The greater this angle, the more effective the anchoring of the end of the fin against the internal wall of the pipe.

[0021] Thus, in the event of the simultaneous occurrence of a sudden leak in the pipe downstream of the device and an overpressure upstream, when the shutter is closed, the "water hammer" caused by this closure cannot cause folding, or buckling, of the fins of the fan washer which would result in this device detaching from the wall of the pipe and no longer performing its function of closing this pipe.

[0022] In embodiments, in the free radial deployment configuration of the fin, at least one center of curvature corresponding to a said radius of curvature is further from the axis of rotational symmetry of the stop device than the end of the free fin.

[0023] Thus, the free end of the fin is, in the free radial deployment configuration, oriented downstream of the device. This orientation allows the fin to slide in a sheath moving from upstream to downstream of the device, for its installation in the predetermined pipeline.

[0024] In embodiments, in its free radial deployment configuration, the radius of curvature of at least one fin is an increasing function of the distance from the axis of the device. The growth of the radius of curvature as a function of the distance from the axis of the device ensures that the resistance of each portion of the fin to bending increases with the moment of the static friction force exerted by the inner wall of the pipe at that portion of the fin. The ability of the device to be held in place in the pipe is thus enhanced.

[0025] In embodiments, in its free radial deployment configuration, the radius of curvature of at least one fin is a decreasing function of the width of the fin, measured perpendicular to the plane passing through the axis of rotational symmetry of the arresting device.

[0026] The decrease in the width of the fin as a function of the distance from the axis of the device ensures that the resistance of each part of the fin to bending increases with the moment of the static friction force exerted by the internal wall of the pipeline at this part of the fin. The capacity of the device to retain in place in the pipeline is thus reinforced.

[0027] In embodiments, in a radial deployment configuration with the free end of at least one fin resting on the inner wall of the predetermined pipeline, the acute angle between the tangent to the free end of the fin in said plane passing through the axis of rotational symmetry of the stop device and the wall of the pipeline is greater than 25 degrees.

[0028] As explained above, this angle is high enough for the anchoring of the end of the fin against the internal wall of the pipe to be effective, even in the event of a large pressure difference between the upstream and downstream sides of the device.

[0029] In embodiments, in its free radial deployment configuration, the distance between the free end of at least one fin and the axis of rotational symmetry of the stop device is at least 15% greater than the radius of the predetermined pipeline (25).

[0030] Such a compression factor of each fin once the device is placed in the pipeline ensures a static friction force of the internal wall on the end of the fin sufficient for the device to remain in place even in the event of a large pressure difference between the upstream and downstream of the device.

[0031] In embodiments, in its free radial deployment configuration, the extension of the fins parallel to the axis of symmetry of the fan washer is between half and three-quarters of the diameter of its base.

[0032] Thanks to these arrangements, the angle of the end of the fins on the internal wall of the pipe to be protected is quite high, which improves its resistance to stress.

[0033] In embodiments, the fins of at least one fan washer are made of austenitic stainless steel with an alloy of chromium (18%) and nickel (8%) (X10 Cr Ni 18.8).

[0034] This stainless steel has good elasticity characteristics after annealing.

[0035] In embodiments, the tubular channel of the seal holder has a diameter configured so that the pressure drop due to the presence of the stop device in the predetermined pipeline under a predetermined pressure is less than a quarter of this predetermined pressure. This low pressure drop thus makes it possible to place two devices one behind the other in the pipeline in the event that the first is defective.

[0036] According to a second aspect, the present invention relates to an excess flow stopping device for stopping a leakage flow on a predetermined fluid pipe when this flow exceeds a predetermined value, this stopping device having an axis of rotational symmetry, this pipe having a predetermined radius and an axis, which comprises:

[0037] - a seal holder comprising a tubular channel having upstream and downstream ends open to the passage of fluid,

[0038] - a shutter facing the upstream end of the tubular channel, retained by a return means in a first position remote from the upstream end of the tubular channel, this shutter providing a surface on which a drag force is exerted by the flow of fluid along this shutter in this first position, the return means being configured so that, when the flow rate is lower than the predetermined value, the shutter remains in the first position and, when the flow rate is higher 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 higher than the predetermined value then retaining the shutter in the second position,

[0039] - an anchoring means configured to anchor the seal holder in the predetermined pipeline,

[0040] - a lip seal which is impervious to the fluid circulating in the pipeline, elastically deformable 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 fixed in a sealed manner to the external wall of the seal holder, in such a way that the only fluid passing through the stop device circulates inside the tubular channel, and

[0041] - a lip seal retaining ring, which comprises a cylindrical central part fixed 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 generally flat shape in a symmetrical trapezoid whose large base is located on the central part, the free radial extension of the fins being equal to or greater than the radius of the predetermined pipeline.

[0042] Thanks to these provisions, the device according to the invention can be compact enough to be inserted, without excavation, into most pipes of known fluid networks, including pipes with small radii of curvature. The lip seal prevents the fluid from passing outside the tubular channel. Thanks to this lip seal, the device operates in pipes of circular section having a radius within a range of radii, pipes which may be crushed and therefore have an elliptical section, the small radius and the large radius of which are within this range of radii. The radial extension of the fins of the retaining ring ensures a bearing force of the lips of the lip seal on the internal wall of the protected pipe which guarantees a seal of this seal for high pressure differences between the upstream and downstream sides of the device.

[0043] The free radial extension of the fins, equal to or greater than the predetermined radius of the pipe, ensures that the periphery of the lip seal rests on the internal wall of the pipe to be protected. In particular, the lip seal alone, for example made of elastomeric material, cannot ensure good sealing against pressurized fluid when the diameter of the pipe is not precisely defined, or when this pipe has an irregularity, a burr, a crushing or a restriction. The retaining ring and its radial fins ensure better sealing of the lip seal in all these cases.

[0044] Thus, thanks to the lip seal and the retaining ring, the device operates in pipes with a circular cross-section having a radius within a wide range of radii, pipes which may be crushed and therefore have an elliptical cross-section, the small radius and the large radius of which are within this wide range of radii.

[0045] When the fluid flow rate is lower than the predetermined value, the shutter remains in the position in which the fluid passes through the tubular channel. However, when the fluid flow rate becomes higher than the predetermined value, particularly in the event of a significant leak downstream of the device, the shutter moves to a second position in which the shutter blocks the upstream end of the tubular channel, thus preventing the fluid from passing through the pipe from upstream to downstream of the device. The anchoring means maintains the device in position in the pipe, thanks to the contact of the free end of each fin against the internal wall of the pipe.

[0046] 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.

[0047] This ratio allows the periphery of the lip seal to be pressurized with the internal wall of the pipe to be protected, even in the event of deformation of this wall resulting, for example, in an elliptical section of this wall. This ratio limited to five percent also prevents the ends of the fins of the retaining ring from touching the internal wall of the pipe, which would risk damaging it. This ratio limited to five percent also prevents the angle at the top of the general 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 is accompanied by folds on the surface of the lip seal.

[0048] In embodiments, the lip seal is fixed to the seal carrier in abutment on an external annular stop of the seal carrier and has an internal shoulder near this stop, such that, when this lip seal is in a folded configuration on the seal carrier, this internal shoulder surrounds this external annular stop of the seal carrier. This internal shoulder makes it possible to compress the lip seal into a configuration where its external surface is substantially cylindrical, so that the fins of the retaining ring can bear on this cylindrical surface without undergoing irreversible deformation.

[0049] In embodiments, the lip seal has, in a 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.

[0050] Thus, the retaining ring receives the lip seal resting on its radial fins. The maintenance of the conical shape of the lip seal is thus ensured even when the pressure difference is high between the upstream and downstream of the device. In addition, an increase in this pressure causes an increase in the bearing force of the periphery of the lip seal on the internal wall of the pipeline.

[0051] In some embodiments, the retaining ring is crimped onto the seal holder. This type of attachment has the advantage of reduced bulk and high mechanical resistance to tearing.

[0052] In 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 have 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 of the device, and flexibility allowing the radial fins of the retaining ring to be folded parallel to the external wall of the seal holder.

[0053] According to a third aspect, the present invention relates to an excess flow stopping device for stopping a leakage flow on a predetermined fluid pipe when this flow exceeds a predetermined value, this stopping device having an axis of rotational symmetry, this pipe having a predetermined radius and an axis, which comprises:

[0054] - a seal holder comprising a tubular channel having upstream and downstream ends open to the passage of fluid,

[0055] - a lip seal which is impervious to the fluid circulating in the pipeline, elastically deformable 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 fixed in a sealed manner to the external wall of the seal holder, in such a way that the only fluid passing through the stop device circulates inside the tubular channel,

[0056] - an anchoring means configured to anchor the seal holder and the lip seal in the predetermined pipeline,

[0057] - a shutter facing the upstream end of the tubular channel, retained by a return means in a first position remote from the upstream end of the tubular channel, this shutter comprising a head provided with a seal offering a friction surface to the flow of fluid along this shutter in this first position, the return means being configured so that, when the flow rate is lower than the predetermined value, the shutter remains in the first position and, when the flow rate is higher than the predetermined value, the shutter moves to a second position in which the head and the seal of the shutter obstruct the upstream end of the tubular channel, the pressure difference between the upstream and downstream of the safety device which corresponds to this flow rate higher than the predetermined value then retaining the shutter in the second position, and

[0058] - a shutter seat mounted on the seal holder and having lateral openings for the passage of fluid towards the head of the shutter and towards the upstream end of the seal holder; stopping device in which the head of the shutter extends a movable body in a guide comprising the return means and in which the shutter seat and the guide have, on the outer surface, a flow deflector configured to reduce the drag of the fluid on the head of the shutter, this flow deflector being carried by the shutter guide and by the shutter seat and having a conical shape whose apex is located in the shutter guide.

[0059] Thanks to these provisions, the device which is the subject 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 the fluid from passing outside the tubular channel. Thanks to this lip seal, the device operates in pipes with a circular section having a radius within a range of radii, pipes which may be crushed and therefore have an elliptical section, the small radius and the large radius of which are within this range of radii.

[0060] When the fluid flow rate is lower than the predetermined value, the shutter remains in the position in which the fluid passes through the tubular channel. However, when the fluid flow rate becomes higher than the predetermined value, particularly in the event of a significant leak downstream of the device, the shutter moves to a second position in which the shutter blocks the upstream end of the tubular channel, thus preventing the fluid from passing through the pipe from upstream to downstream of the device. The anchoring means holds the device in position in the pipe.

[0061] The fluid flow deflector reduces both the pressure drop between the upstream and downstream of the device, when the shutter is open and the instability of this shutter which could be caused by turbulence near its head.

[0062] In embodiments, the head of the shutter has a through opening from a face oriented towards the upstream end of the seal holder to a face oriented towards the shutter guide.

[0063] Thanks to these provisions, after the shutter has closed the tubular channel, then a leak repair is carried out downstream of the device, by allowing the passage of a low flow of fluid, the through opening ensures a rebalancing of the pressures between the upstream and downstream of the shutter and therefore the reopening of the tubular channel. The gas distribution can thus resume automatically after the leak has been repaired, without an operator needing to put the downstream of the pipeline under pressure again. In embodiments, the angle at the top of the conical shape is between 20 degrees and 40 degrees. The inventor has determined that this angle avoids the appearance of turbulence that is harmful to the operating stability of the shutter, while guaranteeing a low pressure loss due to the device. This low pressure loss thus makes it possible to place two devices one behind the other in the pipeline in the event that the first is defective.

[0064] In embodiments, the shutter seat comprises, between its lateral openings, arches whose upstream faces are conical and extend the fluid flow deflector.

[0065] These arches reduce the risk of turbulence appearing in the fluid flow surrounding the device.

[0066] In embodiments, the fluid flow deflector has a maximum diameter greater than three-quarters of the diameter of the shutter seal.

[0067] A drag force is thus maintained on the head of the shutter which carries this seal, in order to cause, when the flow rate is greater than the predetermined value, the movement of the shutter to its second position in which the head and the seal of the shutter obstruct the upstream end of the tubular channel.

[0068] The particular characteristics of the different aspects of the invention are intended to be combined to create other embodiments of the device which is the subject of the invention.

[0069] BRIEF DESCRIPTION OF THE FIGURES

[0070] Other advantages, aims and characteristics of the invention will emerge from the description which follows, given for explanatory and in no way limiting purposes with regard to the appended drawings, in which:

[0071] Figure 1 represents, in exploded perspective, components of a particular embodiment of a stopping device which is the subject of the invention,

[0072] Figure 2 represents, in side view on its upper half and in section on its lower half, the downstream part of a particular embodiment of a stopping device which is the subject of the invention, in its radial deployment configuration resting on the internal wall of a pipe of predetermined radius,

[0073] Figure 3 represents, in side view on its upper half and in section on its lower half, the downstream part of a variant of the stopping device illustrated in Figure 2, in its radial deployment configuration resting on the internal wall of a pipeline of predetermined radius,

[0074] Figure 4 represents, in side view on its upper half and in section on its lower half, the downstream part of a particular embodiment of a stop device which is the subject of the invention, in its operating configuration before a leak occurs on the pipe downstream of the stop device, Figure 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 stop device which is the subject of the invention,

[0075] Figure 6 shows, 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 variant of the stopping device which is the subject of the invention,

[0076] Figure 7 shows, in sectional view, a seal holder of the downstream part of a particular embodiment of the stopping device which is the subject of the invention,

[0077] Figure 8 shows, 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,

[0078] Figure 9 shows, from a downstream view, the fan washer illustrated in Figure 8,

[0079] Figure 10 shows, in side view, the fan washer illustrated in Figure 8, installed in a pipe of predetermined radius,

[0080] Figure 11 shows, in side view, the fan washer illustrated in Figure 8 in the folded configuration for installation in a pipeline,

[0081] Figure 12 shows, in side view, a variant of the fan washer illustrated in Figure 8,

[0082] Figure 13 shows, from a downstream view, the fan washer illustrated in Figure 12,

[0083] Figure 14 shows, in side view, the fan washer illustrated in Figure 12, installed in a pipeline,

[0084] Figure 15 shows, in side view, the fan washer illustrated in Figure 12, in the folded configuration for installation in a pipeline,

[0085] Figure 16 shows, 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,

[0086] Figure 17 shows, in sectional view, the shutter guide illustrated in Figure 16,

[0087] Figure 18 shows, in perspective, a shutter seat of the stop device illustrated in Figure 1, and

[0088] Figure 19 represents, in the form of a flowchart, steps of manufacturing, configuration and installation of a stopping device which is the subject of the invention in a pipeline.

[0089] DESCRIPTION OF EMBODIMENTS

[0090] Throughout the description the following terms are used:

[0091] - “Upstream” the direction from which the fluid comes which passes through the stop device which is the subject of the invention,

[0092] - “Downstream” the direction in which the fluid flowing through the stop device which is the subject of the invention is directed,

[0093] - “Axis of the arresting device” or “central axis of the pipeline”, an axis of rotational symmetry of the arresting device or the pipeline, which are generally confused, - “free radial deployment configuration”, a configuration in which each component of the arresting device extends radially according to its internal mechanical constraints only,

[0094] - “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,

[0095] - “folded configuration” means a configuration in which the elastically deformable components of the stop device are folded by a sleeve for inserting and installing the stop device in the predetermined pipeline.

[0096] We note, from now on, that each of the figures is to scale, even if the scales of the different figures may be different, and

[0097] - “radial” a direction perpendicular to the axis of the stopping device and passing through this axis.

[0098] In Figure 1, we observe the main components of a stop device 30 and an arrow representing the direction of circulation of the fluid going from upstream, on the right, to downstream, on the left. Along the axis of rotational symmetry illustrated in Figure 1, we observe, successively from upstream to downstream, an introduction nose 31, a shutter spring 33, a shutter guide 32, a shutter seat 34, a spacer 38, a seal holder 39, a lip seal 40 and a retaining ring 41. Outside this succession are a movable shutter 35, an O-ring 36 and a fan washer 37. The characteristics and interactions of these components are detailed with regard to the other figures. Their dimensions are adapted to installation and operation in a pipeline of predetermined radius, in which a predetermined fluid, for example a gas, circulates under a predetermined pressure, for example four or six bar.

[0099] As illustrated in Figure 2, the downstream part of the stop device 30 is built on the seal holder 39. This seal holder 39 comprises a tubular channel 398 having upstream and downstream ends open to the passage of the fluid. This tubular channel 398 of the seal holder 39 has a diameter configured so that the pressure drop due to the presence of the stop device 30 in the predetermined pipe 25, under a minimum operating pressure, is less than a quarter, and preferably a sixth of this minimum operating pressure. This low pressure drop thus makes it possible to place two devices 30 one behind the other in the pipe 25 in the event that the first is defective.

[0100] This seal holder 39 carries an anchoring means configured to anchor the seal holder 39 in the predetermined pipe 25. In the figures, a particular embodiment of this anchoring means consists of fan washers 37.

[0101] In Figure 2, the downstream part is in the deployment configuration in support, that is to say presents the deployment of the fins of each fan washer 37 which places them in support on the internal wall of a pipe 25 of predetermined radius. As will be described in more detail with regard to Figures 8 to 15, these fins are then deployed in an intermediate configuration (see Figures 10 and 14) between a folded configuration (see Figures 11 and 15) where they are retained, by a tubular introduction sheath (not shown), along the external wall of the seal holder 39 and a free deployment configuration (see Figures 8, 9, 10 and 13). Each fan washer 37 has the functions of centering the seal holder 39 on the central axis of the pipe to be protected and of anchoring the stop device 30 on the internal wall of this pipe.

[0102] In this particular embodiment comprising three fan washers 37, this downstream part comprises, bearing on 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 have the function of positioning 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 hand, promote the folding of their elastic fins 371 along the external wall of the seal holder 39 in the introduction sheath, before its installation in the pipe to be protected.

[0103] At the downstream end of the seal holder 39, the lip seal 40 and the retaining ring 41 are fixed. At the upstream end of the seal holder 39, the shutter seat 34 is fixed. The lip seal 40 has the function of closing the flow of fluid 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 which passes through the stop device 30 travels through the interior 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 41 has the function of stiffening the lip seal 40 and preventing it from turning over under the effect of excess pressure in the pipe protected by the stop device, in particular when the movable shutter 35 closes the upstream end of the seal holder 39, as explained below.

[0104] 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 has a stop 394 on the external surface of its downstream end.

[0105] As illustrated in Figure 4, the upstream portion of the stop device 30 is designed to allow the movable shutter 35 to obstruct the upstream end of the seal holder 39 in the event of a leak downstream of the stop device 30.

[0106] The movable shutter 35 is located opposite the upstream end of the tubular channel 398. The movable shutter 35 is retained in the shutter 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 shutter 35 is then in its first position remote from the upstream end of the tubular channel 398. The movable shutter 35, provided with the O-ring 36, offers a surface on which the flow of fluid along this shutter 35 in this first position exerts a drag force.

[0107] The head 351 of the shutter 35 extends a body 353 movable in the shutter guide 32. This guide 32 comprises a return means, in this example consisting of the spring 33.

[0108] The return means 33 is configured so that, when the flow rate inside the pipe is less than a predetermined value, the movable shutter 35 remains in the first position. On the other hand, when the flow rate in this pipe is greater than the predetermined value, the movable shutter 35 moves and offers a larger bearing surface to the fluid. So that it continues its movement to a second position in which the head 351 of this movable shutter 35 obstructs the upstream end of the tubular channel 398. This predetermined value is notably reached when there is a significant leak on the protected pipe downstream of the stop device 30. For example, the predetermined value corresponds to a pressure difference between the upstream and downstream of the stop device 30 equal to half the upstream pressure.

[0109] 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.

[0110] This through opening 352 serves to automatically reset the device when the downstream leak is repaired. The reset 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 of the device becomes lower than a predetermined value which depends on the return force exerted by the return means 33. In variants, the movable shutter 35 does not have this through opening, an increase in pressure downstream of the device necessarily being carried out by an operator to reset the device.

[0111] The pressure difference between the upstream and downstream of the stop device 30 which corresponds to this flow rate greater than the predetermined value then retains the shutter in the second position. In practice, the pressure difference between the upstream and downstream is much greater than this predetermined value because, when the movable shutter 35 is closed, the downstream pressure is almost zero. As soon as this pressure difference returns to a value lower 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 in Figure 4.

[0112] In Figure 5, we see the lip seal 40 and the retaining ring 41. The lip seal 40 has a cylindrical peripheral part 401, of diameter equal to or slightly greater (for example one to five percent greater) than the nominal diameter of the pipe to be protected. The lip seal 40 also has a cylindrical central part 403, of diameter equal to or less than (for example one to five percent less) than the diameter of the seal holder 39. The central part 403 of the lip seal 40 is fixed in a sealed manner to the external wall of the tubular channel 398. The lip seal 40 also has a conical part 402 connecting the peripheral part 401 and the central part 403. The lip seal 40 is fixed on the seal holder 39 comprising the tubular channel 398 in abutment on 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 locally reduces the thickness of the conical portion to a value between half and two-thirds of its thickness outside this shoulder 404. This internal shoulder 404 makes it possible to compress the lip seal 40 in a configuration where its external surface is practically cylindrical, so that the fins 412 of the retaining ring 41 can bear on this cylindrical surface without undergoing irreversible deformation. Thus, a smaller thickness of the conical portion at the shoulder 404 makes it possible to create a local weak point. The lip seal 40 thus resists crushing better and the seal is improved when it is deployed.The deployment of the lip seal 40 is therefore carried out without deformation of the fins 412 after the device 30 has been positioned in this pipe 25.

[0113] In Figure 5, the shoulder 404 has a flat crown surface, which bears on 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 crown. A second part of the shoulder 404 is conical and joins the internal conical surface of the upstream face of the lip seal 40.

[0114] The material constituting the 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 section of the predetermined pipe 25. For example, the radius of the part 401, starting 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 in a sealing manner against the inner wall of the pipe 25. Consequently, the only fluid passing through the stop device 30 circulates inside the tubular channel 398 of the seal holder 39.

[0115] The retaining ring 41 comprises a cylindrical central portion 411 configured so that the downstream end of the seal carrier 39 is crimped onto this central portion 411. It also comprises radial fins 412 extending from the central portion 411.

[0116] In Figure 6, we observe a variant of the lip seal 40, in which the internal shoulder 405 of the lip seal 40 has a conical-shaped part extending from the upstream internal surface of the lip seal 40 and a part forming a circular crown bearing on the stop 392 of the seal holder 39.

[0117] At least one of the radial fins 412 has, in its free radial deployment configuration, a generally planar shape in a symmetrical trapezoid, the large 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 pipe 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 pipe 25 to be protected.

[0118] The free radial extension of the fins 412, equal to or greater than the radius of the predetermined pipe 25, ensures that the periphery of the lip seal 40 rests on the internal wall of the pipe 25 to be protected. In particular, the lip seal 40 alone, for example made of elastomeric material, cannot ensure good sealing against the pressurized fluid when the diameter of the pipe 25 is not precisely defined, or when this pipe has an irregularity, a burr, a crushing or a restriction. The retaining ring and its radial fins ensure better sealing of the lip seal in all these cases.

[0119] Thus, thanks to the lip seal 40 and the retaining ring 41, the device 30 operates in pipes 25 of circular section having a radius lying within a wide range of radii, pipes which may be crushed and consequently have an elliptical section, the small radius and the large radius of which lie within this wide range of radii.

[0120] In embodiments, 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. 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 level of sealing of the junction of the lip seal 40 on the inner wall of the pipe 25.

[0121] In the embodiments shown in Figures 5 and 6, the lip seal 40 has, in free configuration, 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 bearing force of the periphery of the lip seal 40 on the internal wall of the pipe 25.

[0122] In embodiments, the retaining ring 41 is crimped onto the seal holder 39 comprising the tubular channel 398. This type of attachment has the advantage of reduced bulk and high mechanical resistance to tearing.

[0123] 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 have 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 of the device and flexibility allowing the radial fins of the retaining ring to be folded parallel to the external wall of the tubular channel.

[0124] It is noted that, preferably, the fins 412 of the retaining ring 41 are connected to the lip seal 40 so that they do not touch the internal 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 characteristic ensures that it is only the lip seal 40 which presses on the internal wall of the pipe 25 and thus ensures the sealing of its junction with this pipe 25.

[0125] The seal holder 39 illustrated in Figure 7 has a generally cylindrical shape with a circular director perpendicular to the axis of the stop device. The interior of this seal holder 39 constitutes the tubular channel 398 for the passage of the fluid. On the external wall of this seal holder 39, from upstream to downstream, we can see 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 and which retains the lip seal 40 and the retaining ring 41. A zone 393 is located between the annular stops 392 and 394. The length of the zone 393, measured parallel to the axis of the stop device, is such that the fins 371 of the fan washers 37 and the lip seal 40 do not touch each other when they are in their folded configuration along the external wall of the seal holder 39, with a view to their installation in the pipe to be protected. In other words, the sum:

[0126] - the length of the conical part 402 of the lip seal 40, measured by following its surface in a section of the lip seal by a plane passing through the axis of the stop device 30,

[0127] - the length of the cylindrical part 401 of the lip seal 40, measured parallel to the axis of the stop device 30 and

[0128] - the length, measured parallel to the axis of the stop device 30, of the fins 371 in their folded configuration (see figures 11 and 15) is greater than the sum:

[0129] - the length of zone 393,

[0130] - the length of the two annular stops 392 and 394, measured parallel to the axis of the stop device 30, and

[0131] - the length of a spacer 38, measured parallel to the axis of the stop device 30.

[0132] A portion 391 of the seal holder 39 is deformed during crimping to fix the seal 40 and its retaining ring 41 on the seal holder 39.

[0133] A chamfer 396 inside the seal holder 39 extends the slope of the shutter seat 34 so as not to create a step for the flow and thus limit pressure losses.

[0134] An excess thickness 397, internal to the seal holder 39, makes it possible 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 shutter seat 34.

[0135] In Figures 8 and 9, we see a fan washer 37, which comprises a central annular part 373 fixed to the seal holder 39 and fins 371 extending in a star shape from the fixed part, or base, 373.

[0136] 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 return force towards a deployment configuration in contact with the internal wall of the fluid pipe. In this radial deployment configuration in support, this free end 372 applies a static friction force on the internal wall of the fluid pipe 25. As explained with reference to FIG. 19, at least one fin 371 is obtained by annealing after its shaping in a free radial deployment configuration.

[0137] This fan washer 37 being produced by cutting and then folding a flat metal plate, which causes this fan washer to lose elasticity, the annealing of each fin 371 makes it possible to give this fin 371 a shape memory increasing the support of the fin 371 on the internal wall of the pipe. In addition, 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 circulate inside the pipe 25 before its installation, even if the internal wall of this pipe 25 has obstacles, burrs, restrictions or curvatures. However, this compression could cause irreversible deformation of this fin 371 if it were not annealed.Now a reduction in the support of the end of the fin 371 on the internal wall of the pipe 25 means a reduction in the static friction force exerted by this wall on the fin 371 to retain the device 30 in position.

[0138] For example, the 37 fan washer is made of austenitic stainless steel with an alloy of chromium (18%) and nickel (8%), referenced “X10 Cr Ni 18.8”.

[0139] Each fin 371 has, at its free end 372, a “T” shape thanks to the presence of shoulders 376. The width of the fins 371, measured perpendicular to a plane passing through the axis of the stop device 30, decreases linearly from their large base on the fixed part 373 to the shoulders 376, then increases from these shoulders 376. This trapezoidal shape visible in figure 9, from the large base to the shoulders 376, makes it possible to limit the size of the fins 371 of a 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 stop 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, we observe that the intermediate fan washer 37 is angularly offset relative to the upstream and downstream fan washers 37.

[0140] When they are free of any external constraint, as in the free radial deployment configuration illustrated in figure 8, each fin 371 extends, in a plane passing through the axis of rotational symmetry of the stop device 30 (the plane of figure 8), and has, from its base in contact with the fixed part 373 to its end 372, a radius of curvature 374A then 375A. This part having a radius of curvature extends, in the embodiment shown in Figure 8, up 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 less than three, and preferably less than two, that is to say that the ratio of its maximum value 375A to its minimum value 374A is less than three, and preferably two. Of course, the radius of curvature preferably varies progressively from its minimum value 374A to its maximum value 375A.

[0141] Thanks to its curvature, 374A and 375A, the fin 371 does not have a bend over a significant part of its extension, or even over its entire extension. The fin 371 therefore does not have a weak zone due to a bend. In addition, the curvature 374A and 375A of the fin 371 allows the angle formed between the end of the fin 371 and the internal wall of the pipe 25, at their point of contact, to be higher than if the fin were straight. However, the higher this angle, the more effective the anchoring of the end of the fin 371 against the internal wall of the pipe.

[0142] Thus, in the event of the simultaneous occurrence of a sudden leak on the pipe 25 downstream of the device 30 and an overpressure upstream, when the shutter is closed, the “water hammer” caused by this closure cannot cause the fins 371 to fold back, which would result in this device 30 detaching from the wall of the pipe 25 and no longer performing its function of closing this pipe 25.

[0143] 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 from the axis of the device 30. The growth of the radius of curvature of the fin 371 as a function of the distance from the axis of the device 30 ensures that the resistance of each portion of the fin 371 to bending increases with the moment of the static friction force exerted by the internal wall of the pipe 25 at that portion of the fin 371. The capacity of the device 30 to be held in place in the pipe 25 is thus reinforced.

[0144] In 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 stop 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 resistance of each portion of the fin 371 to bending increases with the moment of the static friction force exerted by the internal wall of the pipe 25 at that portion of the fin. The capacity of the device 30 to be held in place in the pipe 25 is thus reinforced.

[0145] In embodiments, in a radial deployment configuration with the free end of at least one fin 371 resting on the inner wall of the predetermined pipe 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 stop device 30 with the wall of the pipe 25, is greater than 25 degrees (see figures 10 and 14). 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.

[0146] The centers of curvature corresponding to the radii of curvature 375A, 374B and 375B are 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 have a curvature towards the outside of 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 internal 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 from 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 rotation symmetry of the stop device 30.

[0147] In the example presented in Figure 8, the successive curvatures, moving away from the fixed part 373, successively have two centers located in a plane passing through the fixed part 373. In addition, the two radii of curvature, 374A and 375A, have two values ​​whose ratio of the largest to the smallest is less than three, and preferably less than two and, preferably, less than 1.75. For example, the smallest 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 largest radius of curvature, 375A, near the shoulders 376, measures between one-quarter and 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 thus decreases with the distance to the free end 372 which is in static friction against the internal wall of the protected pipe 25. The inventors have determined that this decrease as a function of the lever arm exerted by this static friction on the fin 371 ensures better flexibility, that is to say capacity for temporary deformation, and therefore better resistance to overpressures which may occur at the level of the stop device 30, in particular at the moment when the movable shutter 35 obstructs the upstream end of the tubular channel 398 of the seal holder 39.

[0148] In another example, for a pipe diameter 25 of 32 millimeters, the diameter of the central annular portion 373 is between 15 and 19 millimeters, the radius 374A is between five and nine millimeters and the radius 375A is between nine and fifteen millimeters. Preferably, the extension of the fins 371 parallel to the axis of symmetry of the fan washer 37, in the free radial deployment configuration, is between half and three-quarters of the diameter of the central annular portion 373. For example, this extension is between eight and fourteen millimeters for a diameter of the central annular portion 373 between 15 and 19 millimeters.

[0149] 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 at least 15% greater than the predetermined radius of the predetermined pipe 25. Such a compression factor of each fin 371 once the device 30 is put in place in the pipe 25 ensures a static friction force of the internal 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.

[0150] It is observed, in Figure 10, that, due to the radial compression of the fins 371, each of their free ends 372 exerts a bearing force perpendicular to the central axis of the pipe 25 on the internal wall of this pipe 25. However, the static friction forces are proportional to these radial bearing forces.

[0151] Preferably, each distal contact surface 378 of the free ends 372 of the fins 371 is curved and configured to be tangent, over its entire length, to the internal wall of a pipe 25 of predetermined diameter. This avoids the risk of scratching the internal wall of the pipe 25, since the contact surface is increased.

[0152] As illustrated in figure 10, in a radial deployment configuration with the free end 372 of at least one fin 371 resting on the internal wall of the predetermined pipe 25, the acute angle between the tangent to the fin 371 in the plane passing through the axis of rotation symmetry of the stop device 30 and the wall of this pipe is preferably greater than 25 degrees.

[0153] 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 smallest radius of curvature 374B of the fin 371 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 largest radius of curvature, 375B, near the shoulders 376 is between 40% and 60% of this diameter, typically half.

[0154] In one example, for a pipe diameter 25 of 22 millimeters, the diameter of the central annular portion 373 is between 13 and 16 millimeters, the radius 374B is between six and ten millimeters and the radius 375B is between eleven and eighteen millimeters. Preferably, the extension of the fins 371 parallel to the axis of symmetry of the fan washer 37, in the free radial deployment configuration, is between half and three-quarters of the diameter of the central annular portion 373. For example, this extension is between seven and twelve millimeters for a diameter of the central annular portion 373 of between 13 and 16 millimeters.

[0155] In Figures 16 and 17, we observe a guide 32 of shutter 35. This guide 32 has an external, upstream cylindrical surface 321, followed by a toric surface 322, 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 driving of the movable shutter 35 by the fluid flow, when the shutter 35 is in its first position described above with reference to Figure 4. In addition, thanks to this deflector 323, the loss of pressure of the fluid, due to the presence of the stop device 30 in the protected pipe, is reduced, as long as the movable shutter 35 is not triggered. On the downstream side, the guide 32 ends with a cylindrical surface 324 threaded for assembly with the shutter seat 34.

[0156] The fluid flow deflector reduces both the pressure drop 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.

[0157] A groove 325 allows for a through thread 324. It is thus possible to screw and tighten the shutter seat 34 onto the shutter guide 32, bearing against the shoulder 326, an through thread 341 of the shutter seat 34 also being a through thread.

[0158] The shutter seat 34 illustrated in Figure 18 has a threaded upstream opening 341 configured to assemble on the threaded surface 324 of the guide 32. The shutter seat 34 has, on its external surface surrounding the opening 341, a conical surface 342 in extension of the conical surface 323 of the guide 32, when the guide 32 and the shutter seat 34 are assembled, as illustrated in Figure 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.

[0159] Alternatively, only the shutter guide 32 or only the shutter seat 34 comprises a deflector. Thus, according to embodiments, the shutter seat and / or the guide have, on the outer surface, a flow deflector configured to reduce the drag force exerted by the fluid on the head of the shutter.

[0160] 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.

[0161] In this example, the apex angle 327 (see Figure 4) of the conical shape of the deflector is between 20 degrees and 40 degrees. The inventor has determined that these values ​​of the angle 327 avoid the appearance of turbulence which is detrimental to the operating stability of the shutter 35, while guaranteeing a low pressure loss due to the device 30. This low pressure loss thus makes it possible to place two devices 30 one behind the other in the pipe 25, in the event that the first is defective.

[0162] 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 shutter 35. A drag force is thus maintained on the head 351 of the shutter 35 which carries this seal 36, in order to cause, when the flow rate is greater than the predetermined value, the displacement of the shutter 35 to its second position in which the head 351 and the seal 36 of the shutter 35 obstruct the upstream end of the tubular channel 398.

[0163] The conical surface 342 has the same angle and the same functions as the conical surface 323. Downstream of the conical surface 342, the shutter seat 34 has three lateral openings 343 which 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, with a different apex angle, the conical surface 342 and participate in limiting the drag force exerted by the fluid on the head 351 and the seal 36 of the shutter 35. These arches 344 reduce the risks of turbulence appearing in the fluid flow surrounding the device 30. Finally, the shutter seat 34 has a downstream ring 345 configured to be screwed around the upstream end of the seal holder 39.

[0164] Figure 19 represents steps of a method 50 for manufacturing and installing the stop device 30 in a pipe 25 to be protected. During a step 51, the different parts of the device 30 are manufactured, with all or part of the technical characteristics set out above. Preferably, during the manufacture of the fan washers 37, they are subject to annealing.

[0165] Annealing brings alloys into physical, chemical and mechanical equilibrium. It tends to achieve structural equilibrium by eliminating the out-of-equilibrium states resulting from previous thermal and mechanical treatments. Annealing corresponds to the maximum values ​​of ductility characteristics (resilience and elongation) and the minimum values ​​of strength characteristics (hardness, elastic limit, breaking load).

[0166] The thermal cycle of an annealing carried out during step 51 includes:

[0167] - heating to a so-called “annealing” temperature which depends on the type of annealing to be carried out,

[0168] - isothermal maintenance at the annealing temperature or oscillations around this temperature,

[0169] - very slow cooling generally in still air, the cooling rate being lower than the critical annealing rate.

[0170] The annealing carried out during step 51 involves heating and holding at (AC3 + 50 °C, where AC3 refers to the temperature of the alpha / gamma transformation in a steel, determined by heating at a rate of 150 to 300 °C / hour) followed by furnace cooling to low degrees of supercooling in order to ensure the decomposition of the austenite and to prevent the formation of high-hardness structures (martensite, bainite). This annealing is carried out on parts that have undergone various thermal and mechanical treatments in order to facilitate their machining or cold deformation.

[0171] Alternatively, annealing requires temperatures below AC1, the eutectoid transformation temperature, including softening annealing and coalescence annealing. Softening annealing is an annealing that is carried out a few tens of degrees below the AC1 temperature (650-680°C) followed by slow cooling in order to obtain a sufficiently stable and, if possible, stress-free state. This treatment aims to improve machinability or cold deformation ability. For high-alloy steels, it is the only treatment that destroys out-of-equilibrium structures and reduces hardness.

[0172] Alternatively, coalescence (or globalization) annealing is used to improve the cold deformation ability of steel, and where the aim is generally to obtain a globular structure of the cementite. This annealing has the effect of improving the machinability of steels by making it possible to apply high cutting speeds and ensuring a very good surface finish. The thermal cycle includes:

[0173] - heating just below the AC1 temperature,

[0174] - prolonged maintenance at this temperature, or oscillation around it,

[0175] - slow cooling to obtain coalescence of the cementite.

[0176] During a step 52, the parts of the stop device 30 are assembled as described above. During a step 53, the lip seal 40, the retaining ring 41 and the fins 371 of the fan washer 37 are compressed towards the axis of the device 30 to reach a folded configuration. During a step 54, the device thus folded is inserted into a cylindrical sheath (not shown). In this folded configuration, the device 30 can move in a pipe and follow its curves without degradation of the device or the pipe. During a step 55, a housing (not shown) is assembled on the pipe to be protected 25 at the customer cabinet.

[0177] During a step 56, a ring is assembled to the sheath and the stop device 30 is introduced into the pipe 25 with this ring. During a step 57, the device 30 is positioned set back from a bifurcation of the pipe to be protected 25, for example a bifurcation connecting the pipe to be protected 25 to a wider supply pipe. During a step 58, the device 30 is removed from the sheath by applying pressure to the ring on which the sheath is fixed. The lip seal 40, the retaining ring 41 and the fins of the fan washer 37 then partially deploy to come to bear on the internal wall of the pipe 25. During a step 59, the stop device 30 is tested by suddenly reducing the pressure downstream of this device and by verifying that the shutter 35 has triggered and closed 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

CLAIMS 1. Device (30) for stopping excess flow for stopping a leakage flow on a predetermined fluid pipe (25) when this flow exceeds a predetermined value, this stopping device having an axis of rotational symmetry, this pipe 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 lip seal (40) sealed against the fluid circulating in the pipe, elastically deformable to a deployed configuration in which the radial extension of the lip seal is greater than the predetermined radius of the pipe, this lip seal being fixed in a sealed manner to the external wall of the seal holder, in such a way that the only fluid passing through the stop device circulates inside the tubular channel, - a shutter (35) facing the upstream end of the tubular channel, retained by a return means (33) in a first position remote from the upstream end of the tubular channel, this shutter providing a surface on which a drag force is exerted by the flow of fluid along this shutter in this first position, the return means being configured so that, when the flow rate is lower than the predetermined value, the shutter remains in the first position and, when the flow rate is higher 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 higher than the predetermined value then retaining the shutter in the second position, and - at least one fan washer (37) comprising at least one elastically deformable fin (371) having a fixed end relative to the seal holder and a free end (372) subjected to an elastic return force towards a deployment configuration in contact with the internal wall of the fluid pipe, in which this free end applies a static friction force to the internal wall of the fluid pipe, in which at least one fin (371) extends, in its free radial deployment configuration, in a plane passing through the axis of rotational symmetry of the stopping device, and has, from its base (373) to its end (372), a radius of curvature (374A, 375A, 374B, 375B) which varies by a factor of less than three.

2. Stop device (30) according to claim 1, in which at least one fin (371) has, in its free radial deployment configuration, from its base (373) to its end (372), a radius of curvature (374A, 375A, 374B, 375B) which varies by a factor of less than two.

3. Stop device (30) according to one of claims 1 or 2, in which, in the configuration of free radial deployment of the fin, at least one corresponding center of curvature at a said radius of curvature (375A, 374B, 375B) is further from the axis of rotational symmetry of the stopping device than the free end (372) of the fin (371).

4. Stop device (30) according to one of claims 1 to 3, in which, 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 from the axis of the device.

5. Stop device (30) according to one of claims 1 to 4, in which, 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, measured perpendicular to the plane passing through the axis of rotational symmetry of the stop device.

6. Stop device (30) according to one of claims 1 to 5, in which, in a radial deployment configuration with the free end (372) of at least one fin (371) resting on the internal wall of the predetermined pipe (25), the acute angle between the tangent to the free end of the fin in said plane passing through the axis of rotational symmetry of the stop device and the wall of the pipe is greater than 25 degrees.

7. Stop device (30) according to one of claims 1 to 6, in which, 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 is at least 15% greater than the radius of the predetermined pipe (25).

8. Stop device (30) according to one of claims 1 to 7, in which, in its free radial deployment configuration, the extension of the fins (371) parallel to the axis of symmetry of the fan washer (37), is between half and three quarters of the diameter of its base (373).

9. Stop device (30) according to one of claims 1 to 8, in which the fins (371) of at least one fan washer (37) are made of austenitic stainless steel with an alloy of chromium (18%) and nickel (8%) (X10 Cr Ni 18.8).

10. Stop device (30) according to one of claims 1 to 9, in which 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 pipe (25) under a predetermined pressure is less than a quarter of this predetermined pressure.

11. Stop device (30) according to one of claims 1 to 10, which further comprises a retaining ring (41) for the lip seal, which comprises 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 plane shape in a symmetrical trapezoid whose large base is located on the central part, the free radial extension of the fins being equal to or greater than the radius of the predetermined pipeline.

12. Stop device (30) according to claim 11, wherein the radial extension of at least one fin (412) of the retaining ring (41), is, in the deployment configuration free radial, between one percent and five percent greater than the predetermined radius of the pipeline (25).

13. Stop device (30) according to one of claims 11 or 12, in which the lip seal (40) is fixed on the seal holder (39) in abutment on an external annular stop (392) of the seal holder and has an internal shoulder (404) close to 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.

14. Stop device (30) according to one of claims 11 to 13, in which 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.

15. Stop device (30) according to one of claims 11 to 14, in which the retaining ring (41) is crimped onto the seal holder (39).

16. Stop device (30) according to one of claims 11 to 15, 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.

17. Stop device (30) according to one of claims 1 to 16, which further comprises a shutter seat (34) mounted on the seal holder and having lateral openings for the passage of fluid towards the head (351) of the shutter and towards the upstream end of the seal holder; stop device in which the head of the shutter extends a body (353) movable in a guide (32) comprising the return means (33) and in which the shutter seat and the guide have, on the outer surface, a flow deflector (323, 342) configured to reduce the drag of the fluid on the head of the shutter, this flow deflector being carried by the shutter guide and by the shutter seat and having a conical shape whose apex is located in the shutter guide.

18. Stop device (30) according to claim 17, in which the head (351) of the shutter (35) has a through opening (352) from a face oriented towards the upstream end of the seal holder (39) to a face oriented towards the shutter guide (32).

19. Stop device (30) according to one of claims 17 or 18, in which the apex angle (327) of the conical shape is between 20 degrees and 40 degrees.

20. Stop device (30) according to one of claims 17 to 19, in which the shutter seat (34) comprises, between its lateral openings, arches (344) whose upstream faces (346) are conical and extend the fluid flow deflector (323, 342).

21. Stop device (30) according to one of claims 17 to 22, in which the fluid flow deflector (323, 342) has a maximum diameter greater than three quarters of the diameter of the seal (36) of the shutter (35).

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