Device for collecting gas from a leak around a flange of a gas pipe

Abstract

A device (10) for collecting gas from a leak around a flange (201) of a gas pipe (200), which comprises: - a hollow body (101, 102, 103) configured to partially surround the flange, the body comprising at least one bearing point (109) bearing on the flange or on the pipe around the flange, - a lower air inlet orifice (117) having a first opening surface-area , and - an upper outlet orifice (104) for an air and gas mixture, having a second opening surface-area, the upper outlet orifice being configured to be positioned higher than the lower air inlet orifice, - the ratio between the first surface-area and the second surface-area being configured to create an upward suction through the body, the air entering through the inlet orifice and an air and gas mixture being discharged through the outlet orifice.

Description

[0001] DEVICE FOR COLLECTING GAS FROM A LEAK AROUND A FLANGE OF A GAS PIPE

[0002] TECHNICAL FIELD OF THE INVENTION

[0003] The present invention relates to a device for diverting gas from a leak in a flange of a gas pipeline. It applies, in particular, to the search for and detection of leaks at the level of flanges in gas pipelines. Hydrogen leaks are particularly targeted, but the present invention can be used for other gases, including methane and biogas.

[0004] STATE OF THE ART

[0005] The operation of gas installations is particularly delicate because of the risk of leaks, for safety reasons (inflammation, explosion, possible toxicity), environmental reasons (emissions impacting the greenhouse effect, possible pollution) and costs (loss of products).

[0006] In particular, the risks are increased with the exploitation of hydrogen (H2), because this gas is more likely to leak than others such as methane (because it is smaller), it is odorless (and generally not odorized), colorless, very easily flammable and its flame is generally barely visible to the naked eye.

[0007] On an installation, flanges are one of the most worrying sources of leakage, because they are non-welded joints, often located below instrumentation facilitating ignition and close to equipment handled by operators.

[0008] Leak control generally involves:

[0009] - fixed gas detectors in places where leaks are likely to be observed;

[0010] - planned leak searches, particularly targeting flanges, for example using soaping techniques and / or measurements with gas sensors.

[0011] Another existing solution is an adhesive tape to be applied around joints such as flanges and which changes color in the event of a hydrogen leak.

[0012] There are also leak-tight devices placed around the flange to contain a possible leak so that measurements can be taken to identify the leak rate. However, installing these devices tightly around the flange can be cumbersome, impossible, or dangerous if the gas is ignited.

[0013] Patent applications WO2023 / 052782A1, WO85 / 00417A1 and US 3,949,596 A, and patent JP 4,600,906B2 are known, which are part of the technological background of the invention. SUMMARY OF THE INVENTION

[0014] The present invention aims to remedy all or part of these drawbacks.

[0015] The present invention makes leak detection more efficient. The present invention also makes it possible to avoid possible exposure of operators to flaming leaks (sometimes invisible, as in the case of hydrogen). In particular, the collected leaks can be directed via the outlet port towards the fixed gas detectors in order to increase the chances of detection.

[0016] The present invention aims to collect any leaks at the flanges to transfer them to a specific point. The present invention makes it possible to:

[0017] - facilitate leak detection by focusing the check on an identified point;

[0018] - avoid ignition by removing the gas outside the instrumentation;

[0019] - avoid exposure of operators to flaming leaks.

[0020] During a planned leak search, the first measurements should be taken at the collection points (end of the remote vent) before continuing with other measurements, particularly at the flange. By doing this, "micro-leaks" have a better chance of being detected, because they are "centralized" at a specific point, and the risk of being exposed to a burning leak is reduced, because the location of such an ignition is identified a priori.

[0021] BENEFITS PROVIDED

[0022] The present invention relates to a device for collecting gas from a leak around a flange of a gas pipe, which comprises:

[0023] - a hollow body configured to partially surround the flange, the hollow body comprising at least one support point on the flange or on the pipe around the flange,

[0024] - a lower air inlet orifice having a first opening surface,

[0025] - an upper outlet orifice for a mixture of air and gas having a second opening surface, the upper outlet orifice being configured to be positioned higher than the lower air inlet orifice,

[0026] - the relationship between the first surface and the second surface being configured to create an upward suction through the body, air entering through the inlet port and a mixture of gas and air being discharged through the outlet port.

[0027] Thanks to these arrangements, the device operates like a chimney and allows the gas from a leak to be evacuated through the outlet. Unlike sealed devices positioned around flanges, the present invention avoids a high concentration of flammable gas.

[0028] In addition, the ratio between the first surface area and the second surface area allows leaks, even low flow rates, to be conveyed to a detector to detect said leak and quantify it. In embodiments, the upper outlet port comprises a flexible tube of dimensions equal to the dimensions of the upper outlet port.

[0029] Thanks to these provisions, for flanges that are difficult to access or positioned at low height from the ground, the flexible tube makes it easier to position the detectors in relation to the flange and therefore increases the comfort of the operator carrying out the measurement. In addition, it is possible to route the gas and air mixture to a detector possibly positioned outside the explosive atmosphere zone (acronym "ATEX").

[0030] In embodiments, the hollow body comprises at least one vent provided with a shutter near the air inlet orifice.

[0031] Thanks to these provisions, the first surface is of variable dimensions and it is possible to adapt to different weather conditions and expected leakage flow, which is in particular a function of the operating pressure of the pipeline.

[0032] In embodiments, the device further comprises a detector of a value representative of environmental data and a means for controlling a position of the shutter as a function of the detected value.

[0033] Thanks to these provisions, the dimensions of the first surface are automatically adapted according to weather conditions during the handling carried out by the operator.

[0034] In embodiments, the hollow body is coated with a thermochromic paint.

[0035] These features make it possible to detect burning leaks, as the thermochromic paint changes color to indicate a heat source. The operator is therefore visually warned to take precautions when handling the device and the flange.

[0036] In embodiments, the outlet orifice is connected to at least one sensor of data representative of a composition and / or a flow rate of the air and gas mixture.

[0037] Thanks to these provisions, it is possible to quantify the possible leak.

[0038] In embodiments for a flange positioned on a substantially horizontal pipeline, wherein the hollow body comprises a fork having two legs connected in a middle, the fork being configured to rest on the pipeline.

[0039] Thanks to these provisions, positioning the device, astride the pipeline and around the flange, is easy for the operator.

[0040] In embodiments, the middle of the fork comprises a magnet.

[0041] Thanks to these arrangements, the device is held against the pipeline by a magnetic force.

[0042] In embodiments, the device of the present invention further comprises a deflector connecting the ends of the fork legs. Thanks to these arrangements, the effect of wind on the flow discharged through the upper outlet orifice is limited. In addition, if the leak is located on the lower part of the flange, the deflector returns the escaping gas to the hollow body.

[0043] In embodiments, the hollow body has two parts configured to be assembled around the flange.

[0044] Thanks to these provisions, the device is easily assembled by the operator.

[0045] BRIEF DESCRIPTION OF THE FIGURES

[0046] Other advantages, aims and particular characteristics of the invention will emerge from the following non-limiting description of at least one particular embodiment of the device and method which are the subject of the present invention, with reference to the appended drawings, in which:

[0047] Figure 1 represents, schematically and in perspective, a first particular embodiment of the device which is the subject of the present invention,

[0048] Figure 2 represents, schematically and from a second perspective, the first particular embodiment of the device which is the subject of the present invention,

[0049] Figure 3 represents, schematically and from a third perspective, the first particular embodiment of the device which is the subject of the present invention,

[0050] Figure 4 represents, schematically and in perspective, a second particular embodiment of the device which is the subject of the present invention,

[0051] Figure 5 represents, schematically and from a second perspective, the second particular embodiment of the device which is the subject of the present invention,

[0052] Figure 6 represents, schematically and from a third perspective, the second particular embodiment of the device which is the subject of the present invention and

[0053] Figure 7 represents, schematically and from a fourth perspective, the second particular embodiment of the device which is the subject of the present invention.

[0054] DESCRIPTION OF EMBODIMENTS

[0055] This description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

[0056] The expression "and / or", as used herein and in the claims, is to be understood to mean "either or both" of the elements so conjoined, i.e., elements which are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" are to be interpreted in the same way, i.e., "one or more" of the elements so conjoined. Other elements may optionally be present, other than the elements specifically identified by the "and / or" clause, whether or not they are related to these specifically identified elements.Thus, by way of non-limiting example, a reference to "A and / or B", when used in conjunction with open language such as "comprising" may refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.

[0057] As used herein in the description and in the claims, "or" is to be understood as having the same meaning as "and / or" as defined above. For example, when separating elements in a list, "or" or "and / or" is to be interpreted as inclusive, i.e., the inclusion of at least one, but also more than one, number or list of elements, and, optionally, additional elements not listed. Only terms clearly indicating the contrary, such as "only one of" or "exactly one of", or, when used in the claims, "consisting of", refer to the inclusion of only one element of a number or list of elements.

[0058] As used in this specification and in the claims, the expression "at least one", with reference to a list of one or more elements, is to be understood to mean at least one element selected from one or more elements in the list of elements, but not necessarily including at least one of each element specifically listed in the list of elements and not excluding every combination of elements in the list of elements. This definition also allows for the optional presence of elements other than the specifically identified elements in the list of elements to which the expression "at least one" refers, whether or not related to those specifically identified elements.Thus, by way of non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B", or, equivalently, "at least one of A and / or B") may refer, in one embodiment, to at least one, optionally including more than one, A, without B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, without A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.

[0059] In the claims, as well as in the description below, all transitional expressions such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "consisting of", and the like, are to be understood as open, i.e., as meaning including, but not limited to. Only the transitional expressions "consisting of" and "consisting essentially of" are to be understood as closed or semi-closed transitional expressions, respectively.

[0060] Please note that the figures are not to scale.

[0061] Although the following description is separated into two embodiments, one relating to a flange positioned on a substantially horizontal pipeline and the other relating to a flange positioned on a substantially vertical pipeline, both embodiments shown relate to the same inventive concept.

[0062] Note that "collection" means "the action of gathering scattered things for a specific action." Said action is not necessarily storage and can be processing, such as taking measurements, for example. The term "collection" could be replaced by "derivation," "diversion," or even "diversion." In other words, collecting a gas consists of changing the direction of the gas flow by directing it toward an outlet.

[0063] We call "top" what is represented at the top of figures 1 to 7, "bottom" what is represented at the bottom of figures 1 to 7, "left" what is represented to the left of figures 1 to 5 and 7 and to the right of figure 6, "right" what is represented to the right of figures 1 to 5 and 7 and to the left of figure 6.

[0064] FLANGE ON A HORIZONTAL PIPE

[0065] Figures 1 to 3, which are not to scale, show schematic views of an embodiment of the device 100 which is the subject of the present invention.

[0066] A substantially horizontal gas pipeline 200 is a pipeline having an axis substantially parallel to a horizontal plane. In Figures 1 to 3, the pipeline 200 is an elongated tube with a circular cross-section. Other forms of pipelines are known to those skilled in the art. A pipeline is defined by an inside diameter and an outside diameter.

[0067] A pipe flange 201 is a metal connection used to consolidate or join two pipe sections. The flange 201 is composed of two discs, each having a circular orifice of the same diameter as the inside diameter of the pipe. Each disc is placed at the end of a pipe 200. The discs are attached to their respective pipes 200 by welding. A disc is therefore integral with a pipe 200.

[0068] The flat surfaces of the discs are positioned against each other and the discs are assembled by screw-nut assemblies, or threaded rods-nuts. The assembly therefore forms a continuous pipe 200. Here, a plane, called the “flange plane”, is defined, corresponding to the contact plane between the discs. The flange plane 201 is substantially vertical and normal to the axis of the pipe 200. A seal is placed between the two discs before assembly in order to preserve the seal of the pipe 200. However, following poor assembly of the flange, due to a defect in the seal originally installed or over time, the seal may fail and cause leaks. The device that is the subject of the present invention makes it possible to divert the gas emanating from the leak and to route it to a control and measurement instrumentation.

[0069] The device 100 for collecting gas from a leak around a flange 201 of a gas pipe 200 comprises:

[0070] - a hollow body, 101, 102 and 103, configured to partially surround the flange 201, the hollow body, 101, 102 and 103, comprising at least one support point on the flange 201 or on the pipe 200 around the flange 201,

[0071] - a lower air inlet orifice 117 having a first opening surface,

[0072] - an upper outlet orifice 104 for a mixture of air and gas having a second opening surface, the upper outlet orifice 104 being configured to be positioned higher than the lower air inlet orifice,

[0073] - the ratio between the first surface and the second surface being configured to create an upward suction through the body, 101, 102 and 103 the air entering through the inlet orifice 117 and a mixture of gas and air being evacuated through the outlet orifice 104.

[0074] The hollow body, 101, 102 and 103, has a convergent shape between the lower air inlet orifice 117 and the upper outlet orifice 104. In other words, if an axis is defined connecting the centers of gravity of the first and second surfaces, for any section perpendicular to said axis, the surface area of ​​the section decreases along said axis from the first surface to the second surface.

[0075] The hollow body, 101, 102, 103 can also be called "envelope", "shell" or even "bell". The hollow body has an internal wall and an external wall of similar shapes, but of different dimensions, the internal wall having smaller dimensions than the external wall.

[0076] The hollow body, 101, 102 and 103, has a general funnel shape having a fork configured to be positioned around the pipe 200 according to a view in the axis of the pipe 200, when the device is positioned on the pipe 200. The hollow body, 101, 102 and 103, has a rectangular parallelepiped shape along a horizontal axis perpendicular to the axis of the pipe 200.

[0077] The hollow body, 101, 102 and 103, comprises two parts called "side parts" configured to be positioned on either side of the flange 201 and one part called "top". The side parts, 101 and 102, are configured to be assembled along a plane parallel to the plane of the flange 201, when the device 100 is positioned on the flange. Preferably, each side part, 101 and 102, has a flat surface, and a rim on a part of its periphery. The flat surface has a fork or inverted Y shape when the device 100 is placed around the flange 201. In other words, the flat surface comprises two legs, 106 and 107, and a body. The legs, 106 and 107, are connected by an arc of a circle 109 of diameter substantially equal to the outside diameter of the pipe 200.The flat surface is defined at the junction between the legs, 106 and 107, by two straight line segments 108 corresponding to the tangent of the circular arc 109 at its ends.

[0078] Preferably, the arc of a circle 109 is less than a semicircle. The straight line segments 108 defining the parts of the legs, 106 and 107, facing each other are therefore not parallel.

[0079] In embodiments, the device 100 comprises at least one wind shield near at least one line segment 108. Such a wind shield may be a retractable fin, for example.

[0080] The flat surface has a plane of symmetry configured to pass through the midpoint of the circular arc 109 and the body.

[0081] The periphery of the flat surface comprises a straight line segment called the "base", interrupted by the shape forming the fork, that is to say the arc of a circle 109 and the two tangent straight line segments 108. On either side of the base, two straight line segments

[0082] 1 19, perpendicular to the base, extend, to define the periphery of the legs, 106 and 107. Said straight line segments 1 19 are configured to have a dimension such that the end of the straight line segment 119 is positioned in a horizontal plane comprising the axis of the pipeline 200.

[0083] The ends of the line segments 1-19 are surmounted by circular arcs

[0084] 120, less than a quarter circle oriented towards each other and moving away from the base, that is to say that their centers are included in the flat surface. And, the ends of these circular arcs 120 are linked to other circular arcs 121 moving away from each other, that is to say whose centers are outside the flat surface. These circular arcs 121 join another straight line segment defining a base, 1 18 parallel to the other base, and configured to assemble with the vertex.

[0085] Preferably, the junctions between the different parts of curves, 119, 120 and

[0086] 121, have a fillet to improve the flow of air or air and gas mixture.

[0087] In embodiments (not shown), the circular arcs, 120 and 121, are elliptical arcs.

[0088] Generally, the planar surface comprises the part defining the fork and the periphery of the planar surface defines two bases connected by a curve, 1 19, 120 and 121, converging whose shape and dimensions are configured to circumscribe the flange 201 without coming into contact with the flange 201.

[0089] The legs, 106 and 107, are configured to be positioned on either side of the pipe 200 when the device 100 is positioned around the flange 201. The legs, 106 and 107, and the hollow body form a curve, 119, 120 and 121, of continuous derivative, that is to say without breaks by an angle.

[0090] The legs, 106 and 107, have ends, 113 and 114, coincident with the base and the body has an end 118 configured to be assembled with the top 103 at the base 118.

[0091] The periphery of the flat surface of at least one lateral portion, 101 and 102, comprises a rim. The rim(s) are configured to extend along the axis of the pipeline 200, when the device 100 is positioned around the flange 201, following the curve, 119, 120 and 121, defining the periphery.

[0092] When only one lateral part, 101 or 102, has a rim, the dimension of the rim, along the axis of the pipe 200, when the device 100 is positioned around the flange 201 is greater than the largest dimension of the flange 201 and of the nuts along the same axis, but less than 1.3 times said dimension.

[0093] When the two lateral parts, 101 and 102, have a rim, the sum of the dimensions of the rims, along the axis of the pipe 200, when the device 100 is positioned around the flange 201 is greater than the largest dimension of the flange 201 and of the nuts along the same axis, but less than 1.3 times said dimension.

[0094] The side parts, 101 or 102, can be assembled by interlocking. For example:

[0095] - when only one lateral part, 101 or 102, has a rim, the rim may have a shoulder provided with a ratchet and the other lateral part, 101 and 102, has a corresponding relief where

[0096] - when the two side parts, 101 and 102, have a rim, one of the rims may have a shoulder fitted with a ratchet and the other rim has a corresponding relief.

[0097] In other embodiments, the side portions, 101 and 102, are joined together using magnetic force. For example, the side portions, 101 and 102, have magnets configured to attract each other and positioned at the one or more edges.

[0098] In embodiments, the middle of the fork comprises a magnet. In other words, a magnet is positioned on the arc of a circle 109 configured to rest on the pipe 200, preferably in its middle.

[0099] In embodiments, the materials and dimensions of the device are configured so that the center of gravity of the device 100 is below a horizontal plane comprising the axis of the pipeline when the device 100 is positioned around the flange 201. In this way, the device cannot tip over in the event of incorrect positioning, even without a magnet on the arc of the circle 109.

[0100] In embodiments, the hollow body, 101, 102 and 103, comprises at least one vent 110 provided with a shutter 111 near the air inlet orifice. Preferably, at least one vent 110 is positioned on the flat surface of a leg, 106 or 107. In embodiments, at least one vent 110 is positioned on the edge of at least one leg, 106 or 107. In embodiments, each lateral part, 101 and 102, comprises at least one vent 110.

[0101] In the embodiment shown, each leg, 106 and 107, of a side portion 102 comprises a vent 110.

[0102] The ventilation 110 may be a series of orifices made in the hollow body, 101, 102 or 103. The orifices are preferably circumscribed by a circle of predetermined diameter and positioned at a distance at least equal to the dimensions of said orifice. The shutter 111 is a disc configured with a diameter at least equal to the predetermined diameter in which orifices are made. The orifices of the shutter 111 are configured to be superimposed on the orifices of the ventilation 110, in the open position, the solid part of the shutter 111 being configured to cover the orifices of the ventilation 110, in the closed position. The shutter 111 has a pivot connection with the hollow body, 101, 102 or 103, the axis of which passes through the center of the circle circumscribing the orifices. Rotating the shutter 111 from a closed position to an open position gradually juxtaposes the vents 110. In other words, the vents are gradually uncovered.

[0103] Each shutter 1 11 can be fitted with an adjustment handle.

[0104] Preferably, the device 100 comprises a detector of a value representative of environmental data and a means for controlling a position of the shutter 11 1 as a function of the detected value. The detector may be a mechanical detector, for example a spring made of a material reacting to a humidity level, or a heat-sensitive material. These embodiments make it possible to position the device in compliance with ATEX standards.

[0105] In embodiments, at least one vent 110 is an orifice provided with fins of adjustable position between a closed position and an open position.

[0106] The vents 110 provided with shutters 111 make it possible to modulate the first opening surface. The vents 110 provided with shutters 111 are configured to adapt the air intakes to the expected leakage rates. The higher the pressure of the gas circulating in the pipe 200, the larger the opening of the shutter 111. Thus, the device 100 is designed for a certain dimension of flange 201 and the vents 110 provided with shutters 111 are adapted to the characteristics of the gas and to the pressure of said gas in the pipe 200.

[0107] The top 103 of the device 100 comprises a base of dimensions corresponding to the dimensions of the upper base 118 of the assembled side parts 102 and 103. The base of the top 103 is configured to fit with the assembled side parts 101 and 102 by any means known to those skilled in the art, for example a shoulder provided with a ratchet. In this way, the top 103 holds the assembled side parts 101 and 102.

[0108] The apex 103 has two lateral planar faces perpendicular to the planar surfaces of the lateral parts 101 and 102, once the device 100 is assembled. These surfaces have a half-disc shape. A peripheral surface connects the two surfaces. An orifice 104 is made in the middle of the peripheral surface. The diameter of the orifice defines the second opening surface.

[0109] Preferably, the upper outlet orifice 104 comprises a flexible tube 105 of dimensions equal to the dimensions of the upper outlet orifice 104.

[0110] In embodiments, the end of the tube 105 not connected to the device 100 may be positioned outside the zone defined by the ATEX standard and include a pump or a vacuum cleaner to create a vacuum in the device 100. In embodiments, the end of the tube 105 not connected to the device 100 may be equipped with a tip configured to be connected to a detector or any device known to those skilled in the art.

[0111] In embodiments, the hollow body is coated with a thermochromic paint. Preferably, the paint is selected so as to change color when the temperature of the hollow body exceeds 50°C.

[0112] Preferably, the outlet orifice 104 is connected, via the tube 105 or not, to at least one sensor of data representative of a composition and / or a flow rate of the air and gas mixture. Such a sensor may be a catalytic detector, a catharometer, an electrochemical detector, or a semiconductor, for example.

[0113] In embodiments, the device 100 further comprises a deflector 112 connecting the ends of the fork legs. The deflector 112 is removable. The deflector 112 is fixed to the lower base, 113 and 114, of the legs, 106 and 107, of the side parts, 101 and 102. The deflector 112 can be assembled by interlocking or by magnetic assembly according to embodiments similar to those described above with regard to the assembly of the side parts, 101 and 102.

[0114] The deflector 112 has a rim around its entire periphery, the rim being assembled with the ends, 113 and 114, of the legs 106 and 107. The deflector forms a concave shape, for example an arc of a circle whose center is in the volume defined by the device 100, between the ends, 113 and 114. The deflector provided with rims is also configured to direct a leak, positioned on the bottom of the flange, towards the legs 106 and 107. The deflector may have water discharge orifices 116 at the low point in the configuration defined above. In this way, once the device 100 is positioned around the flange 201, and the deflector 112 is assembled, any rainwater can be discharged towards the bottom of the device 100.

[0115] Preferably, the device 100 is made of plastic or metallic material and configured to withstand flame temperatures of gas leaks such as hydrogen or methane and corresponding to ATEX standards.

[0116] Figures 2 and 3 show arrows 1-15 showing the suction of air into the device 100.

[0117] FLANGE ON A VERTICAL PIPE

[0118] A substantially vertical gas pipe 400 is a pipe having an axis substantially parallel to the vertical. In Figures 4 to 7, the pipe 400 is an elongated tube with a circular section. Other forms of pipes are known to those skilled in the art. A pipe is defined by an inside diameter and an outside diameter. The flange 401 corresponds to the flange 201, but whose flange plane is substantially horizontal and normal to the axis of the pipe 400.

[0119] The device 300 for collecting gas from a leak around a flange 401 of a gas pipe 400 comprises:

[0120] - a hollow body, 301 and 302, configured to partially surround the flange 401, the hollow body, 301 and 302, comprising at least one support point on the flange 401 or on the pipe 400 around the flange 401,

[0121] - a lower air inlet orifice 305 having a first opening surface,

[0122] - an upper outlet orifice 303 for a mixture of air and gas having a second opening surface, the upper outlet orifice 303 being configured to be positioned higher than the lower air inlet orifice,

[0123] - the ratio between the first surface and the second surface being configured to create an upward suction through the body, 301 and 302, the air entering through the inlet orifice 305 and a mixture of gas and air being evacuated through the outlet orifice 303.

[0124] The hollow body, 301 and 302, has a convergent shape between the lower air inlet orifice 305 and the upper outlet orifice 303. In other words, if an axis is defined connecting the centers of gravity of the first and second surfaces, for any section perpendicular to said axis, the surface area of ​​the section decreases along said axis from the first surface to the second surface.

[0125] The hollow body, 301 or 302, can also be called an "envelope", "shell" or "bell". The hollow body has an internal wall and an external wall of similar shapes, but of different dimensions, the internal wall having smaller dimensions than the external wall.

[0126] The hollow body, 301 and 302, comprises two parts called “side parts” configured to be positioned on either side of the flange 401. The side parts, 301 and 302 are configured to be assembled along a plane perpendicular to the plane of the flange 401, when the device 100 is positioned on the flange 401.

[0127] Once assembled, the side parts, 301 and 302, form an outer casing in the form of a truncated cylinder with a circular directrix curve and a generating curve parallel to the axis of the pipeline 400 when the device 300 is positioned around the flange 401. The lower base of the truncated cylinder is perpendicular to the directrix curves and comprises the lower inlet orifice 305. The upper base 306 forms an angle with the directrix curves less than 90° and greater than 0°. In this way the upper base forms a slope. The highest part of the upper base 306 comprises the upper outlet orifice 303.

[0128] The two parts, 301 and 302, are assembled at two points with a diameter of the lower base. The lower base is open while the upper base 306 is closed.

[0129] Once assembled, the side parts, 301 and 302, form an inner envelope also defined by a truncated cylinder with a circular directrix of diameter strictly smaller than that of the truncated cylinder defining the outer envelope.

[0130] The high base 306 may comprise a support tube 307 on the flange 401. The support tube 307 is defined by a truncated cylinder with a circular base of diameter at least equal to the outside diameter of the pipe 400 and less than 1.3 times the outside diameter of the pipe 400.

[0131] Along the axis of the pipe 400, the dimension of the support tube 307 is such that the high base 306 does not come into contact with the flange 401. In other words, only the low base 308 of the support tube 307 comes into contact with the flange 401. Preferably, the low base 308 of the support tube 307 is normal to the axis of the pipe 400 when the device 300 is positioned around the flange 401.

[0132] The slope of the high base 306 of the device 300 creates a convergence.

[0133] The side parts, 301 and 302, can be assembled by interlocking or by means of a magnet as described above with regard to side parts, 101 and 102, of the device 100.

[0134] In embodiments, the support tube comprises a magnet. The magnet is positioned on the lower base of the support tube to hold the device 300 in place.

[0135] In embodiments, the materials and dimensions of the device are configured so that the center of gravity of the device 100 is below the plane of the flange 401. In this way, the device cannot tip over in the event of incorrect positioning. In embodiments, the hollow body, 301 and 302, comprises at least one vent 110 provided with a shutter 111 near the air inlet orifice. For example, the hollow body, 301 and 302 may comprise a low base 308 partially closed by a flat surface, without coming into contact with the pipe. For example, the flat surface may have the shape of a disc comprising a circular orifice with the center coincident with the center of the disc, the outer diameter of the disc being equal to the diameter of the low base and the diameter of the orifice being greater than or equal to the average between the diameter of the pipe and the diameter of the low base. Each vent 110 is positioned on said flat surface.

[0136] Each shutter 1 11 can be fitted with an adjustment handle.

[0137] Preferably, the device 100 comprises a detector of a value representative of environmental data and a means for controlling a position of the shutter 11 1 as a function of the detected value. The detector may be a mechanical detector, for example a spring made of a material reacting to a humidity level, or a heat-sensitive material. These embodiments make it possible to position the device in compliance with ATEX standards.

[0138] The vents 110 provided with shutters 111 make it possible to modulate the first opening surface. The vents 110 provided with shutters 111 are configured to adapt the air intakes to the expected leakage rates. The higher the pressure of the gas flowing in the pipe 200, the larger the opening of the shutter 111. Thus the device 100 is designed for a certain dimension of flange 201 and the vents 110 provided with shutters 111 are adapted to the characteristics of the gas and its pressure in the pipe 200.

[0139] Preferably, the upper outlet orifice 303 comprises a flexible tube 304 of dimensions equal to the dimensions of the upper outlet orifice 303.

[0140] In embodiments, the end of the tube 304 not connected to the device 300 may be positioned outside the area defined by the ATEX standard and include a pump or vacuum to create a vacuum in the device 300.

[0141] In embodiments, the hollow body, 301 and 302, is coated with a thermochromic paint. Preferably, the paint is selected so as to change color when the temperature of the hollow body exceeds 50°C.

[0142] Preferably, the outlet orifice 305 is connected, via the tube 105 or not, to at least one sensor of data representative of a composition and / or a flow rate of the air and gas mixture. Such a sensor may be a catalytic detector, a catharometer, an electrochemical detector, or a semiconductor, for example.

[0143] Preferably, the device 300 is made of plastic or metal material and configured to withstand flame temperatures of gas leaks such as hydrogen or methane and corresponding to ATEX standards. SIZING OF THE DEVICE

[0144] Whether the flange is horizontal or vertical, the following sizing principles apply to the devices 100 and 200, objects of the present invention.

[0145] The circulation of air in the device, 100 or 200, is ensured by natural convection linked to the temperature difference between the upper outlet orifice, 104 or 303, and the lower inlet orifice, 117 or 305. This phenomenon, also called “thermal draft”, allows a generally upward movement of the air in the device, 100 or 300.

[0146] The thermal draft is amplified by the difference between the first opening surface for the air inlet, 117 or 305, in the lower part, and the second opening surface for the outlet, 104 or 303, in the upper part, which causes an acceleration of the air flow at the level of the upper outlet orifice, 104 or 303, thus creating an upward suction (Venturi effect).

[0147] The design aims to ensure sufficient suction through the Venturi effect. This effect depends on the surface area ratio between the inlet and outlet and the inlet flow velocity. This inlet velocity will be characterized by numerical models for different natural ventilation conditions (orientation and wind speed). The suction can then be estimated from the following equation of Bernoulli's theorem:

[0148] [Chem 1]

[0149] [Chem 2]

[0150] With :

[0151] Where: A represents the section and v the speed, the index 1 corresponding to the input, 1 17 or 305, and the index 2 corresponding to the output, 104 or 303.

[0152] With respect to the device 100, the input surface Ai corresponds to the sum of the surfaces, in the plane of each flat surface of the device 100:

[0153] - bounded by the legs, 106 and 107, and the arc of a circle 109 from which the surface of the pipeline in the same plane is subtracted

[0154] - for each leg, a surface corresponding to the base comprising the ends 1 13 delimited by the lateral parts, 101 and 102, as well as their edges up to the junction with the straight line segment 108, and a straight line connecting, for each leg, the straight line segments 108. In the embodiments in which vents 1 10 are present, the surface in the plane of each flat surface corresponding to the opening of the vents 110 is added to the sum described above to calculate the inlet surface Ai.

[0155] In the embodiments in which the device 100 comprises a deflector 112, the inlet surface Ai corresponds to the sum of the surfaces, in the plane of each flat surface of the device 100, delimited by the legs, 106 and 107 and the arc of a circle 109 and the edge of the deflector 112 from which the surface of the pipeline in the same plane is subtracted.

[0156] In the embodiments in which the deflector 112 comprises orifices 116, the inlet surface Ai corresponds to the sum of the surfaces, in the plane of each flat surface of the device 100, delimited by the legs, 106 and 107 and the arc of a circle 109 and the rim of the deflector 112, to which is added the surface of said orifices 116 and from which the surface of the pipe in the same plane is subtracted.

[0157] This assumption assumes that the flow is incompressible which is a reasonable assumption in the case of the present invention.

[0158] For example, for an inlet velocity of around 0.2 m / s, a depression of 1 mbar would be generated by a surface area ratio of around 64, or a diameter ratio of 8.

[0159] Wind speed and direction can change the air speed and turbulence at the inlet of the device, 100 or 200, and therefore the sizing of the device, 100 or 200, takes into account different wind conditions to verify good air circulation in all configurations.

[0160] Preferably, the flow rate of the outlet orifice, 104 or 303, is configured to correspond to the minimum leak detection flow rate of at least one sensor connected to said outlet orifice, 104 or 303.

[0161] With respect to the device 300, the first surface is defined by the diameter of the orifice 305 and the second surface is defined by the dimensions of the ellipse formatting the orifice 303.

Claims

CLAIMS 1. Device (100, 300) for collecting gas from a leak around a flange (201, 401) of a gas pipe (200, 400), characterized in that it comprises: - a hollow body (101, 102, 103, 301, 302) configured to partially surround the flange, the hollow body comprising at least one support point (109, 308) on the flange or on the pipe around the flange, - a lower air inlet orifice (117, 305) having a first opening surface, - an upper outlet orifice (104, 303) for a mixture of air and gas having a second opening surface, the upper outlet orifice being configured to be positioned higher than the lower air inlet orifice, - the ratio between the first surface and the second surface being configured to create an upward suction through the hollow body, air entering through the inlet and a mixture of gas and air being discharged through the outlet.

2. Device (100, 300) according to claim 1, wherein the upper outlet orifice (104, 303) comprises a flexible tube (105, 304) of dimensions equal to the dimensions of the upper outlet orifice.

3. Device (100) according to one of claims 1 or 2, in which the hollow body (101, 102, 103) comprises at least one ventilation (110) provided with a shutter (111) near the air inlet orifice (117).

4. Device (100) according to claim 3, which comprises a detector of a value representative of environmental data and a means for controlling a position of the shutter (1 11) as a function of the detected value.

5. Device (100, 300) according to one of claims 1 to 4, in which the hollow body (101, 102, 103, 301, 302) is covered with a thermochromic paint.

6. Device (100, 300) according to one of claims 1 to 5, in which the outlet orifice (104, 303) is connected to at least one sensor of data representative of a composition and / or a flow rate of the mixture of air and gas.

7. Device (100) according to one of claims 1 to 6 for flange (201) positioned on a substantially horizontal pipe (200), in which the hollow body (101, 102, 102) comprises a fork having two legs (106, 107) connected in a middle (109), the fork being configured to rest on the pipeline.

8. Device (100) according to claim 7, wherein the middle (109) of the fork comprises a magnet.

9. Device (100) according to one of claims 7 or 8, which further comprises a deflector (112) connecting the ends (113, 114) of the legs (106, 107) of the fork.

10. Device (100, 300) according to one of claims 1 to 9, in which the hollow body (101, 102, 103, 301, 302) comprises two parts (101, 102, 301, 302) configured to be assembled around the flange (201, 401).

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