RU2782396C2 - Leakage detection device - Google Patents

Abstract

FIELD: detection equipment.

SUBSTANCE: group of inventions relates to a device for detection of leakages in a checking zone of sealing membrane of a sealed and heat-insulating tank. The leakage detection device contains a leakage detection dome, a vacuum pump, and an analysis tool. The leakage detection dome includes the main case intended for placement in the checking zone, and a seal connected to the main case and made with the possibility of formation of a detection chamber between the main case and the checking zone. The seal includes a peripheral sealing edge made with the possibility of contact with sealing membrane and having a closed loop embracing the detection chamber. The vacuum pump is connected to the detection chamber for creation of reduced pressure in the detection chamber. The analysis tool is connected to the detection chamber for analysis of gas present in the detection chamber.

EFFECT: increase in the reliability of checking the tightness of sealed membrane of a tank in minimum time.

21 cl, 25 dwg

Description

BACKGROUND OF THE INVENTION

[0001]

[0002] KR1020100050128 discloses a method for testing the tightness of the membrane of a sealed and insulated LNG storage tank. The tank has a multilayer structure and contains in series from the outer side to the inner side an auxiliary insulating space, an auxiliary sealing membrane, a main insulating space and a main sealing membrane designed for contact with liquefied natural gas contained in the tank. In particular, the method is aimed at detecting leaks through welds that provide a hermetic connection between the metal plates of the main sealing membrane. The method involves supplying a tracer gas to the main insulating space and then moving a detection tool equipped with a tracer gas analyzer in the tank along the welds of the main sealing membrane. Thus, if the detection tool detects the presence of a tracer gas, it can be concluded that there is a leak in the main sealing membrane. In such a method, the supply of tracer gas to the main insulating space is extremely important, since the detection method cannot guarantee reliable results if the tracer gas is unevenly distributed throughout the main insulating space.

[0003] In addition, the detection tool consists of a tracer gas suction unit and a tracer gas detector. The suction unit is moved along the weld by means of a trolley, the trolley being located on the bottom wall of the tank, and the suction unit being fixed to the trolley so that it is located above the weld seam of the wall adjacent to the bottom wall. However, when using such a tool, it is difficult to check the integrity of the tank welds because the tool is bulky and needs to be mounted on a trolley on the bottom wall. The tool is also very slow because the tool only checks a small section of the weld at a time and the tool cart assembly needs to be modified to change the weld.

SUMMARY OF THE INVENTION

[0004] One idea underlying the invention is to provide a detection dome or leak detection devices to test the tightness of a sealed reservoir membrane that can be reliably and simply used in a reservoir.

[0005] Another idea behind the invention is to provide a detection dome or leak detection devices that can be used operationally to test the tightness of a sealed reservoir membrane in a minimum amount of time.

[0006] Another idea underlying the invention is to provide a reliable and fast method for checking the tightness of the membrane.

[0007] Some aspects of the invention relate to a leak detection dome, in particular for detecting a leak in the test area of the sealing membrane of a sealed and heat-insulating tank, and the dome includes a main body designed to be placed in the test area, and a seal connected to the main body and configured to form a detection chamber between the main body and the inspection area, wherein the seal includes a peripheral sealing lip configured to contact the sealing membrane and having a closed loop surrounding the detection chamber.

[0008] Some aspects of the invention relate to a device for detecting leaks, including:

- detection dome as described above,

- a vacuum pump connected to the detection chamber to create a reduced pressure in the detection chamber, and

- an analysis tool connected to the detection chamber to analyze the gas present in the detection chamber.

[0009] Some aspects of the invention relate to a method of using such a leak detection device or leak detection dome to detect a leak in a seal membrane test area of a sealed and insulated tank.

[0010] To this end, according to the first object, the invention provides a leak detection device for detecting a leak in a sealing membrane test area of a sealed and thermally insulated tank, the leak detection device including:

- a leak detection dome, which includes a main body designed to be placed in the test area, and a seal connected to the main body and configured to form a detection chamber between the main body and the test area, while the seal includes a peripheral sealing edge made with the possibility of contact with the sealing membrane and having a closed loop around the detection chamber,

- a vacuum pump connected to the detection chamber to create a reduced pressure in the detection chamber, and

- an analysis tool connected to the detection chamber to analyze the gas present in the detection chamber,

in which the sealing lip is configured to have, at least in operation, in which a reduced pressure is created in the detection chamber, a clamping portion sandwiched between the main body and the sealing membrane at least in a portion of the periphery of the detection chamber or over the entire periphery of the detection chamber.

[0011] In accordance with one embodiment, the sealing lip has the flexibility to form said clamping portion by deforming the sealing lip towards the detection chamber under reduced pressure in the detection chamber.

[0012] According to one embodiment, the sealing lip has said clamping portion also at rest, the clamping portion being positioned to cover the entire lower surface of the main body facing the sealing membrane or a portion thereof.

[0013] In accordance with one embodiment, the leak detection dome detection chamber has a convex, for example, circular or polygonal area, designed to cover the connection area between four corrugated or flat metal plates.

[0014] In accordance with one embodiment, the circle geometrically inscribed in the convex zone has a diameter of more than 68 mm.

[0015] In accordance with one embodiment, the detection dome has an elongated shape along the longitudinal axis, and the detection chamber of the leak detection dome includes an elongated zone designed to cover the straight edge of the metal plate, with the convex zone located at one end of the elongated zone.

[0016] In accordance with one embodiment, the bulge is a first bulge, and the leak detection dome detection chamber includes a second bulge located at an end of the elongated zone opposite the first bulge along the longitudinal axis.

[0017] In accordance with one embodiment, the detection dome has an elongated shape along the longitudinal axis, and the convex zone forms the Central portion of the detection chamber of the leak detection dome, while the detection chamber includes two elongated zones, extending from the convex zone in the direction away from each other along the longitudinal axis.

[0018] In accordance with one embodiment, the detection chamber has a convex polygonal or circular shape.

[0019] In accordance with one embodiment, the circle geometrically inscribed in the shape of the detection chamber has a diameter of more than 68 mm.

[0020] The invention also provides a method for using the aforementioned leak detection device in an inspection zone including a junction zone between four corrugated or flat metal plates of a tank seal membrane, the method including the steps of:

- the leak detection dome is placed in the test area in such a way that the sealing lip is in contact with the sealing membrane along the entire periphery of the test area, and the convex zone covers the said connection zone,

- create a reduced pressure in the detection chamber using a vacuum pump,

- clamping the clamping section of the sealing lip between the main body and the sealing membrane, at least in the area of the periphery of the detection chamber,

- direct the gases present in the detection chamber to the analysis instrument, and

- analyze using the analysis tool gases coming from the detection chamber to generate a measurement signal indicating the amount of at least one gas present in the detection chamber.

[0021] In accordance with a second object, the invention provides a leak detection dome for detecting a leak in a test area of a tank seal membrane, the detection dome including a main body designed to be placed in the test area, and a seal connected to the main body and configured to forming a detection chamber between the main body and the test area, wherein the seal includes a peripheral sealing lip configured to contact the sealing membrane and having a closed loop surrounding the detection chamber,

in which the detection dome has an elongated shape in the longitudinal direction and further includes at least one sighting device attached to one longitudinal end of the detection dome, and the sighting device includes an indicator element aligned with the median longitudinal axis of the detection chamber for visual guidance to the operator position of said median longitudinal axis of the detection chamber.

[0022] In accordance with one embodiment, the indicator element includes a pointer or arrow oriented coaxially with the median longitudinal axis of the detection chamber.

[0023] In accordance with one embodiment, the sighting device includes a light source, and the indicator element includes a directional light beam oriented coaxially with the median longitudinal axis of the detection chamber.

[0024] According to one embodiment, the light source is a laser source, such as a laser diode.

[0025] In accordance with one embodiment, the detection dome includes two sighting devices attached to two opposite longitudinal ends of the detection dome, each of which includes an indicator element aligned with the median longitudinal axis of the detection camera to visually indicate to the operator the position of said median longitudinal axis of the detection chamber.

[0026] In accordance with one embodiment, the detection dome further includes at least one handle located on an upper surface of the detection dome facing away from the sealing lip.

[0027] In accordance with one embodiment, the detection dome includes two handles located on the upper surface near the two longitudinal ends of the detection dome.

[0028] The invention also provides a method of using the detection dome described above on a sealing membrane including a plurality of generally rectangular metal plates welded to each other, wherein the inspection zone includes a straight edge of one of said metal plates, wherein the method includes the step of placing the detection dome on the sealing membrane and aligning the indicator element of one or each sighting device with said straight edge.

[0029] The metal plates are preferably overlap welded with the straight edge of the metal plate offset in the thickness direction of the sealing membrane relative to the adjacent metal plate and positioned to overlap the adjacent metal plate.

[0030] According to a third object, the invention provides a leak detection device for detecting leaks in a sealing membrane test area of a sealed and thermally insulated tank, the leak detection device includes:

- a portable leak detection dome, wherein the detection dome includes a main body designed to be placed in the test area, and a seal connected to the main body and configured to form a detection chamber between the main body and the test area, the seal includes a peripheral sealing edge , made with the possibility of contact with the sealing membrane and having a closed loop surrounding the detection chamber, while the detection dome additionally includes a manipulation handle having a manual actuation element for issuing a control signal,

- a gas suction circuit for connecting the detection chamber to a vacuum pump, the gas suction circuit being provided with a controllable valve configured to switch to an open state to connect the detection chamber to the vacuum pump, and a closed state to disconnect the detection chamber from the vacuum pump, and

- a control unit configured to switch the control valve in response to a control signal.

[0031] In accordance with one embodiment, the control unit is configured to alternately switch the controlled valve between an open state and a closed state in response to a control signal.

[0032] In accordance with one embodiment, the control element is a first manually operated engagement element for issuing a first control signal, and the detection dome further includes a second manually operated engagement element for issuing a second control signal,

wherein the control unit is configured to switch the control valve to an open state in response to the first control signal, and to a closed state in response to the second control signal.

[0033] In accordance with one embodiment, the manipulation handle is a first manipulation handle, and the detection dome further includes a second manipulation handle, which is provided with a second control unit.

[0034] In accordance with one embodiment, one or each manipulation handle is located on the top surface of the detection dome, facing away from the sealing lip.

[0035] In accordance with one embodiment, the control valve is mounted on the detection dome.

[0036] In accordance with one embodiment, the device further includes an analysis tool connected to the detection chamber by a gas suction circuit, and a pressure sensor configured to provide a measurement signal indicative of pressure in the detection chamber to the control unit, and the control unit is configured with the possibility of determining that the pressure in the detection chamber is below a predetermined pressure threshold, and activating the analysis tool in response to this.

[0037] In accordance with one embodiment, the pressure sensor is located on the detection dome and is in fluid communication with the detection chamber.

[0038] In accordance with one embodiment, the analysis tool includes a mass spectrometer.

[0039] In accordance with one embodiment, the gas suction circuit includes a hose connected to the gas outlet of the detection dome.

[0040] In accordance with one embodiment, the gas suction circuit further includes a three-way connector, the openings of which are respectively connected to a hose, a vacuum pump, and an analysis tool.

[0041] In accordance with one embodiment, the device further includes a movable cart on which a control unit, a vacuum pump, and an analysis tool are mounted.

[0042] In accordance with one embodiment, the device further includes a flexible electrical cable connecting the control unit to the detection dome for transmitting a control signal or signals and/or power supply.

[0043] In accordance with one embodiment, the control valve is a three-way valve configured to communicate between the detection chamber and the surrounding atmosphere when closed.

[0044] According to a fourth object, the invention provides a leak detection method for detecting leaks in a tank seal membrane test area using a leak detection dome,

moreover, the leak detection dome includes a main body and a seal connected to the main body and configured to form a detection chamber between the main body and the sealing membrane, the seal includes a peripheral sealing edge configured to contact the sealing membrane and having a closed loop, surrounding the detection chamber, wherein the leak detection dome further includes a mechanical pressing means mounted on the main body and including at least one pressing element configured to apply pressure to the sealing lip portion in the direction of the membrane when the main body located in the inspection area, and

said sealing membrane includes a plurality of corrugated or flat metal plates welded to each other,

wherein the leak test method includes the steps of:

- placing the detection dome on the sealing membrane in such a way that the detection chamber is located at the level of at least one weld between the first metal plate and the second metal plate, and placing the clamping element in such a way that it exerts pressure on the sealing edge section, which intersects said weld,

- lower the pressure in the detection chamber with a vacuum pump,

- directing the gas phase contained in the detection chamber to the analysis tool to detect the gas present in the detection chamber.

[0045] Embodiments of such a method may have one or more of the following features.

[0046] In accordance with one embodiment, the leak detection dome detection chamber includes a convex zone, wherein said pressure member for applying pressure to a portion of the sealing lip that intersects said weld is located at the periphery of the convex zone.

[0047] In accordance with one embodiment, the weld between the first metal plate and the second metal plate is the first weld, and the pressing element is the first pressing element, and the convex zone of the detection chamber is also located at the level of the second weld connecting the first or a second metal plate with a third metal plate, the mechanical pressing means further including a second pressing element disposed to exert pressure on a portion of the sealing lip which intersects said second weld.

[0048] In accordance with one embodiment, the metal plates are substantially rectangular, and the detection chamber is located at the level of the joint zone between the first, second, third metal plates and the fourth metal plate, and the joint zone further includes a third weld connecting the first or a second metal plate with a fourth metal plate, wherein the mechanical pressing means further includes a third pressing element positioned to exert pressure on a portion of the sealing lip that intersects said third weld.

[0049] In accordance with one embodiment, the detection dome has an elongated shape along the longitudinal axis of the detection chamber, and the leak detection dome includes an elongated zone designed to cover the straight edge of the metal plate, with the convex zone located at one end of the elongated zone.

[0050] The clamping element or elements can be made in different ways. In accordance with one embodiment, the pressing element includes a rod movably mounted relative to the main body, a spring pushing the rod towards the sealing lip, and a support element attached to one end of the rod and abutting against the sealing lip under the action of the spring.

[0051] In accordance with one embodiment, the pressing element includes first and second rods mounted for movement relative to the main body at a distance from each other, springs pushing said rods in the direction of the sealing edge, and an elongated support element having a first end attached to one end of the first rod, and the second end attached to one end of the second rod, and said elongated support element abuts against the sealing edge under the action of the springs.

[0052] In accordance with one embodiment, the pressing element includes a plurality of adjusting elements mounted on the main body and forming a line, and the adjusting element includes a rod extending perpendicularly in the direction of the sealing edge, and the rod has an end, the position of which can be adjusted in the longitudinal direction of the rod to ensure contact with the sealing lip.

[0053] In accordance with one embodiment, the pressing element further includes a distribution base plate located between the ends of said rods and the sealing lip.

[0054] In accordance with other preferred embodiments, such a dome may have one or more of the following features.

[0055] In accordance with one embodiment, the detection dome includes:

- mechanical pressing means mounted on the main body and including at least one pressing element configured to exert pressure on the sealing lip portion in the direction of the membrane when the main body is located in the test area.

[0056] Due to these features, the detection dome can be quickly placed in the inspection area so that the seal can form a detection chamber over the entire inspection area. In addition, the mechanical pressing means makes it possible to press the sealing lip in one or more areas, in particular in places where there is a risk of the seal detaching from the sealing membrane, so that the detection of leaks by the detection dome is more reliable.

[0057] The detection dome can preferably detect a tracer gas supplied for the purpose of testing, such as helium or ambient air gas. According to one possibility proposed by the invention, the tracer gas is not necessarily fed into the zone being tested for leaks, but can be supplied to the zone in some other way. By "ambient air" it is necessary to understand the gas phase having a composition close to the surrounding dry air, i.e. containing approximately 78% nitrogen, 21% oxygen, 0.9% argon, as well as inert gases and volatile organic compounds that can be released by the adhesive used in a thermal barrier, or solid insulating materials.

[0058] In addition, due to the leak detection dome according to the invention, an absolute pressure of less than 100 Pa can be easily obtained in the chamber, for example, a pressure of the order of 50-60 Pa (0.5-0.6 bar).

[0059] In accordance with one embodiment, the pressing element is an elastically deformable element that exerts pressure on a portion of the sealing lip due to elastic deformation.

[0060] Accordingly, the resilience of the pressing member allows it, during elastic deformation, to exert a rebound force on the sealing lip towards the sealing membrane.

[0061] In accordance with one embodiment, the pressing element is oriented perpendicular to the contour of the peripheral sealing lip.

[0062] According to one embodiment, the sealing lip has an operating state in which the detection chamber is depressurized and the clamping portion of the sealing lip is held between the main body and the sealing membrane at least in a portion of the periphery of the detection chamber, preferably throughout the periphery of said chamber.

[0063] In accordance with one embodiment, the leak detection dome has an elongated shape, the length of which is greater than or equal to 0.5 m, preferably greater than or equal to 1 m, more preferably greater than or equal to 2 m. In addition, the leak detection dome may have a width 10 to 20 centimeters (cm), preferably 14 cm to 16 cm.

[0064] With regard to the weight of the detection dome, it can be from 3 kg to 25 kg inclusive, preferably from 5 kg to 10 kg inclusive, in particular, depending on the materials used, its length and width.

[0065] According to one embodiment, the mechanical pressing means includes a plurality of pressing elements configured to apply pressure to a plurality of sealing lip portions, the portions being located at the two ends of the sealing lip in the longitudinal direction.

[0066] In accordance with one embodiment of the invention, the portions of the sealing lip pressed by the mechanical pressing means are located at the two ends of the sealing lip in the longitudinal direction, i.e. at both ends of the dome, given that the latter has a generally longitudinal shape.

[0067] Accordingly, the mechanical pressing means exerts pressure on different areas where there is a risk of seal detachment, namely the ends of the seal.

[0068] In accordance with one embodiment, the sealing lip includes at least one cavity shaped to match the corrugation of the membrane, the cavity being designed to cover the corrugation.

[0069] According to one embodiment, the sealing lip includes at least two pits, such as three pits.

[0070] With these features, it is possible to place a detection dome on a sealing membrane composed of corrugated plates, with the dimple or dimples allowing the dome to cover the corrugations.

[0071] Therefore, a leak detection dome, when used in a membrane zone including corrugations, allows inspection of weld zones present on a plurality of corrugations, for example, from at least three (3) corrugations up to almost ten corrugations. It may also be possible to combine a plurality of detection domes next to each other or one behind the other to form a longer length of the inspection zone. According to one embodiment, a single vacuum pump may be used to generate the vacuum required in the leak detection domes connected to each other.

[0072] According to one embodiment, the portion of the sealing lip pressed by the mechanical pressing means is located at the base of the trough.

[0073] With this feature, it is possible to place a detection dome on a sealing membrane composed of corrugated plates, with the dimple or dimples allowing the dome to enclose the corrugations.

[0074] Accordingly, the mechanical pressing means exerts pressure in a zone in which there is a risk of the seal detaching due to a change in the inclination of the cavity.

[0075] In accordance with one embodiment, the mechanical pressing means includes a plurality of pressing elements configured to exert pressure on a plurality of areas of the sealing lip, the areas located at the bases of the trough or troughs.

[0076] Accordingly, the mechanical pressing means exerts pressure on different areas where there is a risk of the seal coming off, namely the base of the depression or depressions.

[0077] According to one embodiment, the sealing lip portion is located on the top of the cavity.

[0078] In accordance with one embodiment of the invention, all areas of the sealing edge located at the bases of the cavity are pressed by a plurality of pressing elements of the mechanical means.

[0079] In accordance with one embodiment, at least one, some or all of the pressing elements include a curved bar, at least one end of which abuts against the base of the cavity.

[0080] At least one, some or all of the pressing elements preferably include a curved bar, the two ends of which abut against the base of two adjacent depressions.

[0081] Due to this feature, placement of the leak detection dome is simplified because the curved bar allows the troughs of the sealing lip to be placed on two adjacent corrugations of the membrane with sufficient pressure, regardless of possible slight changes in the distance between two adjacent corrugations or the approximate placement of the leak detection dome on the corrugated membrane by one or multiple operators.

[0082] In accordance with one embodiment, the carrier element extends the entire length of the main body over the latter and is attached to the main body.

[0083] In accordance with one embodiment, the curved strips are distributed along the sealing lip and attached to the support element by fasteners.

[0084] In accordance with one embodiment, the curved strips are elastically deformable to exert an elastic return force on the sealing lip upon deformation.

[0085] In accordance with one embodiment, the fasteners include a plurality of pins, each pin including a rod movably mounted on the housing, one end of the rod abuts against one of the curved strips, the housing is attached to the carrier and includes a spring connecting the rod to the housing, the spring operating between the housing and the rod to position the end of the rod so that it abuts against the curved strip, and the spring is configured to exert a return force on the curved strip so that the curved strip presses the sealing lip against the base of the corrugation.

[0086] According to one embodiment, the mechanical pressing means includes a plurality of end pressing elements, the end pressing elements being located at the two ends of the sealing lip in the longitudinal direction, i.e. at the two ends of the dome, given that the latter has a longitudinal shape.

[0087] In accordance with one embodiment, at least one or all of the end clamps include an end pin, wherein the end pin includes a rod movably mounted on the body, an elongated support member is attached to one end of the rod, an elongated support element abuts against the sealing lip and the body is attached to the carrier, the end pin also includes a spring connecting the stem to the body, the spring operating between the body and the stem to accommodate the elongated support member so that it abuts against the sealing lip, the spring made with the possibility of exerting a return force on the elongated support element so that the elongated support element presses the sealing edge against the test zone.

[0088] In accordance with one embodiment, the second end is provided with an elongated support member, the elongated support member being configured to transmit an elastic rebound force to the sealing lip area along the length of the elongated support member.

[0089] In accordance with one embodiment, the second end of the first end pin and the second end of the second end pin adjacent to the first end pin are connected to each other by means of an elongated support member.

[0090] In accordance with one embodiment, at least one or all of the end pressure elements include a plurality of adjusting elements forming a line of elements, the adjusting element including a stem extending in the direction of the sealing lip and having an end that can be adjusted in the longitudinal direction of the rod to ensure contact with the sealing lip after adjustment.

[0091] In accordance with one embodiment, the pressing element includes a curved strip containing a cylindrical sleeve at one of the ends in contact with the sealing lip.

[0092] Accordingly, the cylindrical sleeve allows the mechanical pressing means to exert uniform pressure on the sealing lip portion.

[0093] In accordance with one embodiment, the sealing lip includes a sheath that at least partially covers the main body and is attached to the main body, the peripheral sealing lip being connected to the sheath, extending it and folding away from the main body.

[0094] According to one embodiment, the cylindrical sleeve has a longitudinal direction, wherein the longitudinal direction of the cylindrical sleeve is substantially orthogonal to the shell such that the cylindrical sleeve extends from the shell to one end of the sealing lip.

[0095] According to one embodiment, the sealing lip includes a folded portion substantially orthogonal to the shell, the folded portion having a cross-sectional dimension greater than or equal to 1 cm, preferably greater than or equal to 1.5 cm, more preferably greater than or equal to 2 cm

[0096] In accordance with one embodiment, the seal is made of an elastomeric material having a hardness of 20 to 50 Shore A, inclusive.

[0097] Due to these features, the seal is made of a material that is flexible enough to deform under the action of mechanical pressing means.

[0098] In accordance with one embodiment, the elastomeric seal material is selected from a polyurethane elastomer and ethylene propylene diene rubber (EPDM). The elastomeric seal material can also be silicone, nitrile, or Viton® material.

[0099] In accordance with one embodiment, the main body includes a rigid base, and the seal includes a shell sealed against a peripheral wall of the rigid base.

[0100] In accordance with one embodiment, the rigid base includes a recess on the bottom surface facing the test area.

[0101] In accordance with one embodiment, the rigid base includes a channel connecting the recess to the top surface of the rigid base for connecting a vacuum pump.

[0102]

[0103] In accordance with one embodiment, the leak detection dome is oriented in the test area such that the leak detection dome overlaps the test area lengthwise.

[0104] In accordance with one embodiment, the test zone is the weld area of the sealing membrane.

[0105] Accordingly, the leak detection dome allows you to check for a defect in the weld, which can lead to leakage in the sealing membrane.

[0106] In accordance with one embodiment, the test zone is located on the corrugated sealing membrane.

[0107] According to one embodiment, the shape of the peripheral sealing lip corresponds to the geometry of said at least one corrugation.

[0108] According to one embodiment, the weld area is traversed by at least two parallel corrugations, for example three parallel corrugations of the membrane, and the shape of the peripheral sealing edge corresponds to the geometry of said corrugations.

[0109] In accordance with one embodiment, the peripheral sealing lip includes at least two pits, the shape of which corresponds to the shape of the corrugation of the membrane, protruding towards the inside of the reservoir, and the said pits are intended to enclose the said corrugation.

[0110] In accordance with one embodiment, at least one corrugation of the membrane protrudes into the reservoir, and the detection dome is adjacent to the membrane in such a way that the depressions surround the corrugation.

[0111] In accordance with one embodiment, the peripheral sealing lip includes at least two protruding zones, the shape of which corresponds to the shape of the corrugation of the membrane protruding towards the outside of the tank.

[0112] In accordance with one embodiment, the detection dome is adjacent to the membrane such that the raised zones are inserted into the corrugation.

[0113] In accordance with one embodiment, the pressure in the detection chamber is reduced to an absolute pressure value from 10 to 1000 Pa inclusive, preferably less than 100 Pa absolute pressure.

[0114] In accordance with one embodiment, the gas phase is analyzed for 5 seconds or more.

[0115] In accordance with one embodiment, a variable representing the amount of gas in said gas phase is compared with a threshold value, and it is determined that the tightness of the weld area is compromised if the representative variable exceeds said threshold value.

[0116] According to embodiments, the analysis tool is configured to detect a tracer gas or detect an ambient air component.

BRIEF DESCRIPTION OF THE DRAWINGS

[0117] The present invention will become more clearly understood and other objects, details, features and advantages will become more apparent as the following description of a variety of specific embodiments of the invention is given by way of non-limiting illustration only with reference to the accompanying drawings.

[0118] FIG. 1 is a schematic view of a leak detection device according to the first embodiment.

[0119] FIG. 2 is a sectional view in plane II-II of the detection dome of the leak detection device shown in FIG. one.

[0120] FIG. 3 is a perspective view of a seal according to the first embodiment.

[0121] FIG. 4 is a schematic view of an alternative leak detection device in which the detection dome is equipped with a clamping system.

[0122] FIG. 5 is a perspective view of a seal according to the second embodiment.

[0123] FIG. 6 schematically illustrates the placement of the detection dome facing the sealing weld between two adjacent corrugated metal membrane plates.

[0124] FIG. 7 is a schematic view of a leak detection device according to the second embodiment.

[0125] FIG. 8 is a perspective view of the leak detection dome according to the third embodiment.

[0126] FIG. 9 is a schematic sectional view of the detection dome shown in FIG. 8 until the pressure in the detection chamber is reduced.

[0127] FIG. 10 is a schematic sectional view of the detection dome shown in FIG. 8 after depressurizing the detection chamber.

[0128] FIG. 11 is a schematic illustration of a multilayer membrane tank wall structure.

[0129] FIG. 12 is a schematic partial view of a sealed and insulated tank illustrating tracer gas supply devices passing through the bottom wall membrane of the tank.

[130] FIG. 13 is a perspective view of the leak detection dome according to the fourth embodiment.

[0131] FIG. 14 is an enlarged view of the area XIV shown in FIG. 13 illustrating the pressure element of the leak detection dome.

[0132] FIG. 15 illustrates an enlarged view of the area XV shown in FIG. 13 illustrating the first end of the leak detection dome.

[0133] FIG. 16 illustrates an enlarged view of the area XVI shown in FIG. 13 illustrating the second end of the leak detection dome.

[0134] FIG. 17 illustrates an enlarged view of the area XVI shown in FIG. 13 from a different angle.

[0135] FIG. 18 is a top view of the sealing membrane, schematically illustrating the detection dome positioned to check the connection between four rectangular plates.

[0136] FIG. 19 is a view similar to FIG. 18 illustrating another geometry of a detection dome positioned to test the connection between four rectangular plates.

[0137] FIG. 20 is a view similar to FIG. 18 illustrating another geometry of a detection dome positioned to test the connection between four rectangular plates.

[0138] FIG. 21 is a plan view of the leak detection dome shown in FIG. 13, also illustrating the optical sighting device.

[0139] FIG. 22 is a schematic functional view of a leak detection device using the leak detection dome shown in FIG. 13.

[0140] FIG. 23 is a diagram illustrating an activation method that can be used in the leak detection device shown in FIG. 22.

[0141] FIG. 24 is a diagram illustrating a deactivation method that can be used in the leak detection device shown in FIG. 22.

[0142] FIG. 25 is a schematic functional diagram of a three-way valve that can be used in the leak detection device shown in FIG. 22.

DESCRIPTION OF EMBODIMENTS

[0143] Next, a leak detection device that can be used to detect leaks in various sealed assemblies, such as a welded assembly, will be described. In the examples below, the weld assembly is a fluid reservoir sealing membrane.

[0144] The leak detection device 54 shown in FIG. 1 is used in the leak test step to check the seal of the membrane welds 5, 8.

[0145] The leak detection device 54 includes a detection dome 55 designed to be placed against the inner surface of the membrane 5, 8 facing the area of the weld being tested.

[0146] The detection dome 55 has an elongated shape, and its length is from 0.5 to 4 m inclusive, for example, about 1 m. The length of the detection dome 55 is preferably the maximum possible to test the tightness of a larger area during one and only test. However, the choice of dome length can be adapted, on the one hand, in accordance with the dimensions of the tested membrane 5, 8, and, on the other hand, taking into account the involvement of a minimum number of operators to work with it, preferably one operator. The elongated shape is particularly suitable for testing a rectangular metal plate assembly in which the welds substantially follow the straight edges of the plates.

[0147] As shown in FIG. 2, the detection dome 55 includes a rigid main body 100 and a flexible seal 60, which are connected to each other and are configured to form with the membrane under test 5, 8 a sealed detection chamber 61 facing the site of the weld 62 under test.

[0148] Returning to FIG. 1, it can be seen that the leak detection device 54 also includes an analysis tool 56, which is connected to the detection chamber 61 and allows detection of a given gas, for example, a tracer gas or a gas from the ambient air present on the other side of the weld under test. When the analysis tool 56 detects a predetermined gas in excess of a threshold value, it can be concluded that the portion of the weld 62 under test is leaking. In accordance with one embodiment, the analysis tool 56 is a mass spectrometer.

[0149] The leak detection device 54 also includes a vacuum pump 57 that is connected to said analysis tool 56. The vacuum pump 57 is connected on the one hand to the detection chamber of the detection dome 55 to reduce the pressure in the detection chamber, and on the other hand to the analysis tool 56 to supply the gas contained in the detection chamber 61 to the analysis tool 56 .

[0150] The vacuum pump 57 is connected to the detection dome 55 by a tube 58, which is preferably flexible. The tube 58 is connected to a channel formed in the main body 100 and exits to the detection chamber 61 .

[0151] As shown in Figures 2 and 3, the main body 100 includes a rigid base 59, and the seal 60 includes a shell 63 that follows the shape of the rigid base 59 and a peripheral sealing lip 64 that extends the shell 63 downward. The shell has a bottom 63 which covers the upper surface of the rigid base 59 and a peripheral wall 74 which follows the periphery of the rigid base 59. with a vacuum pump 57. The rigid base 59 includes, on the bottom surface 80, a recess 79 along the entire length of the rigid base 59. During depressurization of the detection chamber 61, the recess 79 ensures that the area to be tested 62 will always be in fluid communication with the chamber 61 detection, despite the movement of the rigid base 59 downwards in the direction of the membrane 5, 8 due to the deformation of the sealing lip 64. In addition, the rigid base 59 also includes a channel 82, which is not shown in FIG. 2, since it extends only in a plane at the level of the tube 58, connecting the recess 79 with the upper surface 81 of the rigid base 59. The channel 82 provides communication of the detection chamber 61 with the vacuum pump 57 and the analysis tool 56 through the tube 58.

[0152] The peripheral sealing lip 64 is folded outwards of the detection dome 55 and therefore can flex and press against the membrane 5, 8 when the pressure in the sealed chamber 61 is reduced. In other words, the peripheral sealing lip 64 has a generally L-shaped cross section. .

[0153] The outwardly folded portion of the peripheral sealing lip 64 has a width of the order of 15-40 mm. The shape of the peripheral sealing lip 64 corresponds to the geometry of the membrane 5, 8 along the weld being tested. Also in FIG. 3, the peripheral sealing lip 64 includes depressions 65, the shape of which corresponds to the shape of the corrugations of the membrane 5, 8, which are covered by the detection dome 55 when it is in position opposite the area of the weld 62 being tested.

[0154] Seal 60 is preferably made of an elastomeric material having a hardness of 20 to 50 Shore A, inclusive. The seal, for example, is made of polyurethane elastomer, ethylene propylene diene rubber (EPDM), silicone, nitrile or Viton®.

[0155] FIG. 3 also illustrates the median longitudinal axis 20 of the detection chamber 61 enclosed by a peripheral sealing lip 64. In operation, it is desirable to correctly center the detection chamber 61 on the weld being inspected, in particular because the detection chamber 61 can be relatively narrow. To this end, the detection dome 55 may include a sighting device which, as shown in FIG. 3 is made in the form of two indicator points 21 located at the two longitudinal ends of the detection dome and oriented coaxially with the median longitudinal axis 20. Alternatively, only one of the two indicator points 21 can be provided. In this case, the indicator points 21 are integral with the peripheral sealing edge 64, this ensures that the indicator points 21 are in close proximity to the membrane 5, 8 and therefore limits the risks of sighting errors due to parallax. However, the indicator dots 21 may be provided in other ways, such as attached parts. The indicator dots 21 may be attached to other parts of the detection dome 55 .

[156] FIG. 21 illustrates an optical sighting device consisting of two laser diodes 22 attached to the two longitudinal ends of the detection dome 55 and emitting light beams 23 also oriented coaxially with the median longitudinal axis 20. Alternatively, only one of the two laser diodes 22 can be provided. the diode 22 may be located on the peripheral sealing lip 64 or above the peripheral sealing lip 64, for example on the carrier 73, which will be described below. In this case, the light beam 23 is preferably slightly inclined downwards in order to strike the membrane 5, 8 and therefore limit the risks of sighting errors due to parallax.

[0157] In the embodiment schematically illustrated in FIG. 4, the detection dome 55 is further provided with a mechanical clamping means 66, which in this embodiment is a clamping system 66 for pressing the peripheral sealing lip 64 against the membrane 8 to be tested to seal the detection chamber 61. In this case, the clamping system 66 includes a clamp 67 at the level of each of the recesses 65 of the peripheral sealing edge 64. Each clamp 67 includes two branches located on respective opposite sides of the recess 65 and configured to apply a force pressing the peripheral sealing edge 64 to the membrane 8. The branches are preferably configured to press the peripheral sealing lip 64 against the sealing membrane near the base of the corrugation.

[0158] In addition, in the illustrated embodiment, the clamping system 66 further includes, at the level of each of the longitudinal ends of the detection dome 55, a movable pin 68 that is configured to press one of the longitudinal ends of the peripheral sealing lip 64 against the membrane 8.

[0159] FIG. 5 illustrates a seal 60 in accordance with an alternative embodiment. The shape of the seal 60 corresponds to the membrane 5, the corrugations of which protrude towards the outside of the tank. Such a membrane is, for example, an auxiliary membrane 5 according to Mark V technology. Also, the peripheral sealing lip 64 includes protruding zones 69 intended to be inserted into the corrugations of the membrane 5.

[0160] The weld leak detection procedure is performed as follows.

[0161] First, the detection dome 55 is placed facing the portion of the weld to be tested 62 that extends along the straight edge of the rectangular plate as shown in FIG. 6.

[162] It is necessary to ensure that the detection dome 55 is properly centered with respect to the weld 62 such that the two side portions of the folded portion of the peripheral sealing lip 64 are located on respective opposite sides of the weld 62.

[0163] In this regard, in FIG. 6 also shows the targeting device, in this case in the form of two indicator dots 21, which the operator accurately places on the weld 62 in order to align the median longitudinal axis 20 of the detection chamber with the weld 62. In the case of the optical targeting device shown in FIG. 21, the light beams 23 must be positioned so that they are exactly superimposed on the weld 62.

[0164] FIG. 6 also schematically illustrates the contour 30 of the detection chamber 61, namely the sealing contact line between the peripheral sealing lip 64 and the membrane 5, 8.

[0165] Then, the vacuum pump 57 is started to reduce the pressure in the detection chamber 61 and to facilitate the passage of gas through the defective areas of the weld 62.

[0166] As soon as the pressure in the detection chamber 61 falls below the pressure threshold value Ps, the gas flow from the detection chamber 61 is supplied to the analysis tool 56, and the rate (leakage of a given gas, for example, tracer gas) is measured for a minimum period Tm. Then speed (leaks are compared with a threshold value ϕs.

[0167] If the rate (leakage is below the threshold value ϕs, it is concluded that there is no leak in the weld area 62 to be checked. In this case, the detection dome 55 is disconnected from the membrane 5, 8 by relieving the reduced pressure in the detection chamber 61, for example, by opening of the gas inlet 71 shown in Fig. 7. The detection dome 55 is then placed facing the adjacent section of the weld 62 with an overlap between the two successively tested sections to ensure that the tightness of the weld 62 is checked along the entire length of said weld 62.

[0168] In contrast, if the leak rate is greater than or equal to the threshold value ϕs, it is concluded that there is a seal failure in the weld area 62 to be tested. Corrective welding is then performed to correct the failure.

[0169] By way of example, at a helium concentration in the heat-insulating space of about 20%, the threshold pressure value below which the leakage rate is measured is from 10 to 1000 Pa absolute pressure, inclusive, preferably less than 100 Pa absolute pressure. For example, the minimum duration of leakage rate measurement is 5 seconds, and the threshold value ϕs is in the order of 1.0⋅10 ^-6 Pa⋅m ^3⋅ s ^-1 .

[0170] FIG. 7 illustrates a leak detection device 54 according to another embodiment. This embodiment differs from the embodiment described above in that it further includes a homogenization chamber 70 located between the detection chamber 61 and the analysis tool 56, and in that the detection dome 55 includes a gas inlet 71.

[0171] The gas supply channel 71 is equipped with a cock that allows the supply or interruption of the flow of ambient air into the detection chamber 61 . The homogenization chamber 70 is connected to one end of the detection chamber 61, while the gas supply channel 71 is connected to the opposite end of the detection chamber 61 .

[0172] The device 54 for detecting leaks operates as follows.

[0173] When the detection dome 55 is located facing the area of the weld 62 to be tested, the valve of the gas supply channel 71 is closed and the vacuum pump 57 is started to reduce the pressure in the detection chamber 61. As soon as the pressure in the detection chamber 61 drops below the threshold pressure value Ps, the valve of the gas supply channel 71 is opened, and all the gas previously contained in the sealed chamber is supplied to the homogenization chamber 70. The homogenization chamber 70 has a volume larger than that of the detection chamber 61 and, for example, includes a piston system for properly sucking all the gas contained in the detection chamber 61 .

[0174] Then, the gas contained in the homogenization chamber 70 is supplied to the analysis tool 56 to determine the rate (gas leakage.

[0175] This embodiment is advantageous in that it reduces the propagation time of the gas in the detection dome 55 and thus reduces the minimum measurement time. This is particularly advantageous when the time it takes for gas to move from one end of the detection dome 55 to the other end can be significant due to the long length of the detection dome 55 and/or insufficient pressure reduction in the detection chamber 61 .

[0176] FIG. 8 illustrates the detection dome 55 according to the third embodiment. The detection dome 55 shown in FIG. 8 has a structure similar to the detection dome 55 shown in FIG. 4, but differs in particular with respect to the mechanical pressing means 66. In fact, the detection dome 55 includes a main body 100 extending in the longitudinal direction, a flexible seal 60 attached to the main body 100, and a mechanical pressing means 66, mounted on the main body and configured to exert pressure in the direction of the membrane 5, 8 on the seal 60. The main body 100 includes a rigid base 59. The rigid base 59 includes a channel 82 connecting the lower surface 80 with the upper surface 81 of the rigid base 59. Channel 82 provides communication between the detection chamber 61 and the gas outlet 78.

[0177] The seal 60 includes a shell 63 attached to the rigid base 59 by means of a fastening means 110, for example, consisting of a hoop surrounding the periphery of the rigid base 59 and seal 60 and connecting these two elements 59/60 to each other by means of a mechanical fastener, such as screws. The seal 60 also includes a peripheral sealing lip 64 connected to the sheath 63 and having a closed loop to enclose the area of the weld 62 being tested. membrane 5, 8. The peripheral sealing edge 64 also has a plurality of depressions 65 spaced from each other along the periphery, and the shape of the depressions 65 corresponds to the shape of the corrugations of the tested membrane 5, 8. Thus, when placing the detection dome 55 on the membrane 5, 8, the depressions 55 allow the detection dome 55 to adapt to the corrugated shape of the membrane 5, 8. The gas outlet 78, which allows gas to be removed when the pressure in the detection chamber 61 is reduced, passes, in particular, through the main body 100 and the carrier 73.

[0178] The carrier 73 extends the entire length of the main body 100 over the latter and is attached to the main body 100. Handles 76 are attached to the two longitudinal ends of the carrier 73 to allow the operator to operate the detection dome 55 and possibly actuate the mechanical pressing means. due to the effort exerted by the operator.

[0179] The mechanical clamping means 66 is composed of a plurality of clamping elements 72 in the form of curved strips 72 distributed along the sealing lip 64 and attached to the carrier 73 by fasteners 77. The curved strips 72 are elastically deformable so that when they deformed, they exert an elastic return force on the sealing lip 64, pressing it against the membrane 5, 8. To reliably ensure the tightness of the detection chamber 61, it is advisable to press the sealing lip 64 in areas with a higher risk of detachment. Therefore, the curved strips 72 are located in particular at the bases of the depressions 64 of the sealing edge 64 and at the longitudinal ends of the detection dome 55 on the sealing edge 64.

[0180] A plurality of curved strips 72 are attached at one end to the carrier 73 while the other end is located on the sealing lip 64. The strips 72 are particularly located at the ends of the detection dome 55. Other curved strips 72 are attached centrally to the carrier 73, while their two ends are located on the sealing lip 64, exerting pressure on two different zones, such strips 72, in particular, are located between two depressions 65.

[0181] Curved strips 72 have at each end a cylindrical sleeve 75 in contact with sealing lip 64. Cylindrical sleeve 75, in particular, provides a uniform fit to the sealing lip 64, which prevents it from piercing, which can compromise the integrity of the sealing lip 64. Cylindrical sleeve 75 extends in a direction orthogonal to the longitudinal direction of the main body 100. In addition, the length of the cylindrical sleeve 75 is substantially equal to the size of the portion of the sealing lip 64 protruding from the main body 100 in the direction of passage of the cylindrical sleeve 75. Thus, the cylindrical sleeve 75 allows the mechanical clamping means 66 effectively apply pressure to the sealing lip.

[0182] When placing the leak detection dome 55 in the test area, it is necessary to ensure that the mechanical clamping means 66 is tight and properly presses the seal 60 to properly test the tightness of the weld. Therefore, the problem is to ensure that the mechanical pressing means 66 performs its function around the entire periphery of the peripheral sealing lip 64. However, the inspection zone, in particular at the ends of the detection dome 55, may be a connection zone between a plurality of corrugated metal plates, for example , four corrugated metal plates, as a result of which the zone is not completely flat, but has level differences, which makes it difficult to press the seal 60.

[0183] FIG. 13 illustrates the detection dome 55 according to the fourth embodiment, in which the mechanical pressing means 66 is reinforced at the ends of the detection dome 55 to compensate for insufficient area flatness. The detection dome 55 shown in FIG. 13 has a structure similar to the detection dome 55 shown in FIG. 8, but differs in particular in the shape of the detection chamber having two circular zones at two longitudinal ends which are wider than the central straight strip. Other differences relate to the mechanical pressing means 66. In fact, the detection dome 55 shown in FIG. 13 also includes a main body 100 extending in the longitudinal direction, a flexible seal 60 attached to the main body 100, and a mechanical pressing means 66 mounted on the main body and configured to exert pressure in the direction of the membrane 5, 8 on the seal 60. However, in this case, the mechanical pressing means 66 includes pressing elements 72 and end pressing elements 87.

[0184] Each pressing element 72 includes a curved strip 72, at least one end of which abuts against the base of the cavity 62. One of the ends of the curved strips 72, located between two adjacent depressions, is located at the base of one of the depressions one of the ends is located at the base of the other of the valleys 65. In this case, as illustrated in FIG. 14, the clamping elements 72 are secured by fasteners 77, each of which includes a pin 83. Each pin 83 includes a rod 85 movably mounted on the housing 84. One end of the rod 85 abuts one of the curved strips 72. The body 84 is attached to the carrier 73. The pin 83 also includes a spring 86 connecting the shaft 85 to the body 84, the spring 86 operating between the body 84 and the shaft 85 to position the end of the shaft 85 so that it abuts against the curved strip 72. Thus thus, the spring 86 is configured to apply a return force to the curved band 72 so that the curved band 72 presses the sealing lip 64 against the base of the corrugation.

[0185] The end pressing members 87 are located at the two ends of the sealing lip 64 in the longitudinal direction, i. e. at the two ends of the leak detection dome 55, given that the latter has a generally longitudinal shape. The end clamps 87 can be designed in many different ways, which may or may not be combined on a single leak detection dome 55 . For brevity, in FIG. 13, one leak detection dome 55 shows three options for end clamps 87.

[0186] Figures 15-17 illustrate three variations of end pressure members 87. As illustrated in FIG. 15, in accordance with the first embodiment, the end pressure member 87 includes an end pin 88. Each end pin 88 includes a rod 90 movably mounted on the housing 89. element 91 abuts against sealing lip 64. Housing 89 is attached to carrier 73. End pin 88 also includes a spring 86 connecting stem 90 to housing 89, spring 86 operating between housing 89 and stem 90 to accommodate elongated support member 91 so so that it rests against the sealing lip 64. Thus, the spring 86 is configured to apply a return force to the extended support member 91 so that the extended abutment member 91 presses the sealing lip 64 against the test area. Thus, the return force acts on the sealing lip 64 along the entire length of the extended support member 91. In the case of the first embodiment shown in FIG. 15, each extended support member 91 is attached to only one shaft 90 of the end pin 88.

[0187] A second embodiment of the end pressure member 87 is illustrated in FIG. 16. The second option differs from the first option in the elongated support element 91 of the end pins 88, other features of the end clamping elements 87 are retained. In this embodiment, the elongated support member 91 is attached to one end of the shaft 90 of the first end pin 88 and to one end of the stem 90 of the second end pin 88 adjacent to the first end pin 88. In this case, the elongated support member 91 is longer than in the first embodiment and, therefore pressed by two end pins 88 distributed along its length to form a longer bearing portion on the sealing lip 64.

[0188] A third embodiment of the end pressure members 87 is illustrated in FIG. 17. In this embodiment, the end pressure member 87 includes a plurality of adjustment members 92 forming a line of members. The adjusting element 92 includes a rod 93 extending in the direction of the sealing lip 64 and perpendicular to the test area, and an end 94 whose position can be adjusted in the longitudinal direction of the rod to ensure contact with the sealing lip 64 after adjusting the rod 93. Thus, due to the adjusting elements 92, the end pressure member 87 can be adjusted more precisely to fit the test area more closely and thus improve the tightness of the detection chamber 61 .

[0189] FIG. 17 also illustrates a distribution backing plate 95 that can be positioned between the ends 94 of the rods 93 and the top surface of the sealing lip 64 to limit the risk of piercing the sealing lip 64 and therefore increase its durability. Distribution base plate 95 may be an elongated plate in a generally straight shape or, as shown, an arcuate shape following the contour of the sealing lip 64. Its material may be a rigid plastic polymer. Sleeves are preferably formed on the upper surface of the distribution base plate 95 to receive the ends 94 and therefore fix the distribution base plate 95 to the rods 93.

[0190] Next, the method of using the leak detection dome 55 illustrated in FIG. 8, in a leak detection device 54 including said dome 55, a vacuum pump 57 connected to the detection chamber 61 through a gas outlet 78, and an analysis tool 56. The use of such a detection device 54 makes it possible to check the tightness of the weld 62 between the two corrugated plates of the sealing membrane 5, 8.

[0191] First, one or more operators, using the handles 76, place the detection dome 55 in the area to be tested, in this case the weld 62. To do this, the main body 100 of the detection dome 55 is placed over the weld 62 so that the length the main body 100 has been aligned and centered with respect to the weld 62. If necessary, the sighting device described above can be used for this. Thus, the sealing lip 64 is located on either side of the weld 62 and completely encloses the area of the weld 62 to be tested to form, with the main body 100 and the membrane 5, 8, a sealed detection chamber 61, as seen in FIG. 9.

[0192] After positioning the detection dome 55 over the weld 62, the detection dome 55 is attached like a suction cup to the membrane 5, 8 by the vacuum force of the vacuum pump 57. If applicable, the vacuum force activates the mechanical pressing means 66 so that it redirects the pressure to press the sealing lip 64 against the membrane 5, 8 in certain well-defined areas.

[0193] When the mechanical pressing means 66 exerts force on the carrier 73, the carrier 73 transmits the force to the curved strips 72 through the respective fasteners, which generally resiliently deforms the curved strips 72. Due to this and due to the springback effect, the curved the strips 72 transmit force to the sealing lip 64 through the cylindrical bushings 75 in the areas where the sealing lip is most likely to detach, namely at the longitudinal ends of the main body 100 and at the bases of the depressions 65.

[0194] The vacuum pump 57 creates a reduced pressure in the detection chamber 61 through the channel 82 and the gas outlet 78. The flexibility of the sealing lip 64 causes it to deform during the creation of a reduced pressure in the detection chamber 61 which tends to reduce the volume of the detection chamber 61 . In fact, the sealing lip 64 approaches both sides of the weld 62 as seen in FIG. 10. Once the pressure in the detection chamber 61 falls below the pressure threshold value Ps, the gases present in the detection chamber 61 are supplied to the instrument 56 for analysis.

[0195] Then, the analysis tool 56 analyzes during the measurement time Tm the concentration of gases present in the detection chamber 61 to obtain a value indicative of a change in concentration. This representative value is then compared to a threshold value to determine whether the area of the weld 62 being tested has a leak or not.

[0196] If the measured value is less than a threshold value, it is concluded that the area to be tested has no leaks, in which case the detection dome 55 is placed facing the adjacent area of the weld 62 with an overlap between the two successively tested areas to ensure the leak test of the weld 62 along the entire length of said weld 62.

[0197] If the measured value is greater than or equal to the threshold value, it is concluded that the test portion of the weld 62 has a leak. Then, to eliminate the violation, corrective welding work is carried out. Measurements can also be provided using an optional detection tool to more accurately determine the location of a leak.

[0198] Thus, the sealing lip 64 preferably occupies two positions, depending on whether it is in its original state, that is, without creating a reduced pressure in the detection chamber 61, or in its operating state, in which a reduced pressure is created.

[0199] In the initial state, the sealing lip 64 rests without pressure on the surface of the sealing membrane 5, 8, while in the working state, at least the clamping portion 53 located at the inner end of the sealing lip 64 is sandwiched under the main body 100, completely sealing the contour or periphery of the detection chamber 61 . In fact, due to the flexibility of the sealing lip 64, the latter is clamped between the main body 100 and the membrane 5, 8 when a reduced pressure is created. The placement of the clamping section 53 of the sealing edge 64 between the main body 100, which flattens or presses it, and the sealing membrane 5, 8 effectively contributes to the achievement of perfect tightness of the detection chamber 61, which allows you to create and maintain a vacuum with a pressure of not more than 1500 Pa (15 barns) or even at much lower pressures.

[0200] In accordance with a preferred embodiment, the sealing lip 64 is in operation when the detection chamber 61 is underpressured such that the clamping portion 53 of the sealing lip 64 is held between the main body 100 and the sealing membrane 5, 8 at least in a portion around the periphery of the detection chamber 61 or even around the entire periphery of said chamber 61. Due to such clamping, the mechanical clamping means described above can be partly or completely dispensed with.

[0201] In an alternative embodiment, the peripheral sealing lip 64 is provided with a clamping portion 53 permanently protruding under the main body 100, i.e. also in the original state in the absence of reduced pressure, for example, around the entire periphery of the detection chamber 61 or in a periphery section.

[0202] As indicated above, the inspection zone may be a connection zone between a plurality of metal plates, such as four rectangular metal plates, corrugated or not. Such use of the detection dome 55 will be described below with reference to Figures 18-20.

[0203] With regard to the area of connection between a plurality of flat rectangular plates, you can refer to, for example, the publication EP-A-0064886. In US-A-4021982, FIG. 24 shows a connection area between a plurality of corrugated rectangular plates. In these examples, as in Fig. 18, each of the four rectangular metal plates 31 includes a sheared corner 32, for example, forming a corner 45(with the edges of the plate. The four sheared corners 32 are placed overlapping on a metal insert 33 attached to the insulating housing, the central zone of which, in this case square shape, remains open between the four cut corners 32. The central zone of the metal insert 33 forms part of the sealed membrane due to the sealed welding lines made along the cut corners 32.

[0204] The dotted lines 34 show bends when offset in the thickness direction of the rectangular metal plates 31, which provide mutual overlap in accordance with known technology.

[0205] In FIG. 18, the detection dome has a shape corresponding to the embodiment shown in FIG. 13. The position of the detection dome is shown schematically by the outline of the sealing lip 64 and the outline 30 of the detection chamber 61, some of which are illustrated. In particular, the circular zone 25 of the detection chamber 61 is located at the level of the aforementioned connection zone, for example, centered on the open part of the metal insert 33, while the central straight strip 24 of the detection camera 61 is located on the straight edge of one of the rectangular metal plates 31. Circular zone 25 of the detection chamber 61 has a diameter to completely surround the four cut corners 32 at the level of the aforementioned junction area. To do this, for example, the diameter exceeds 68 mm for a Mark III® pleated membrane.

[0206] In FIG. 18, the end pressure members 87 are shown schematically in dotted outline. Therefore, it can be noted that the end pressure elements 87 are positioned on the detection dome in such a way that when the detection dome is placed at this location, the end pressure elements 87 are actually at the level of the welds 62 that connect the rectangular metal plates 31 to each other at the edges. . Consequently, the end pressure members 87 press on portions of the peripheral sealing lip 64 which bear on the welds 62, which in any case have some relief. The end clamps 87, arranged in this way, make it possible to obtain a perfectly sealed contact despite this relief. In particular, as seen in FIG. 18, three end pressing members 87 press on three portions of the peripheral sealing lip 64 which respectively intersect three welds 62 in the joint area.

[0207] The end clamps 87 illustrated in FIG. 18 preferably have a straight or curved elongated shape. In particular, they can be made in the form of elongated pressure elements 91, as in FIG. 16, or with a distribution base plate 95 as in FIG. 17.

[0208] Other geometries of the detection dome may be envisaged for such use. In the embodiment shown in FIG. 19, the detection dome has a modified shape in which the circular zone 25 forms the central portion of the detection chamber 61 and the detection chamber 61 has two elongated zones 24 extending from the circular zone 25 in diametrically opposite directions along the median longitudinal axis 20. In the embodiment shown in fig. 20, the detection dome has a modified shape in which the detection chamber 61 has a round shape.

[0209] In the case shown in FIG. 19, it can be seen that the two end pressure members 87 press on two portions of the peripheral sealing lip 64 which respectively intersect the two welds 62 in the joint zone at diametrically opposite positions to the circular zone 25. In the case shown in FIG. 20, it can be seen that the four end pressure members 87 press on four portions of the peripheral sealing lip 64 which respectively intersect the four welds 62 in the joint area.

[0210] Alternatively, instead of the circular zone 25, a convex polygonal shape can be used, in which case the circle, geometrically inscribed in the shape of the detection chamber, should have a diameter that completely surrounds the four cut corners 32 at the level of the aforementioned connection zone.

[0211] Next, with reference to Figures 22-25, an embodiment of the leak detection device 54 in which the detection dome 55 according to the fourth embodiment can be used will be described.

[0212] The leak detection device 54 includes a detection dome 55, an analysis tool 56 with a corresponding vacuum pump 57, if applicable, a second larger vacuum pump 37, and a suction circuit connecting the detection chamber 61 to the analysis tool 56 via electromagnetic valve 48. The suction circuit preferably includes a relatively long length of hose 58 to allow movement of the detection dome 55 over a relatively wide working area around the analysis tool 56. The hose 58, for example, is connected by connectors 39, on the one hand, to the outlet of the detection chamber 61, and, on the other hand, to the analysis tool 56. When using a second vacuum pump 37, a junction connector 38 may be provided to connect the analysis instrument 56 and the second vacuum pump 37 in parallel.

[0213] To control the solenoid valve 48, and, if applicable, other elements, for example, the analysis tool 56, in response to operator actions in relation to one or more controls of the detection dome 55, located, for example, on one or more handles 76 detection dome 55, a control unit 36 is also provided.

[0214] For example, in the case of the detection dome 55 according to the fourth embodiment, each of the two handles 76 is equipped with a push button that can be operated by the thumb and is respectively configured as an activation button 51 and a deactivation button 52. Instead, other types of controls other than a push button may be provided, such as a capacitive touch button, a rotary knob, or any other element that can be operated manually.

[0215] In the preferred mode of operation, the vacuum pump 37 or other source of reduced pressure is activated in advance and constantly creates a reduced pressure in the suction circuit. The solenoid valve 48 is closed by default, as a result of which a reduced pressure is not initially created in the detection chamber 61, which allows the detection dome 55 to move freely along the membrane 5, 8.

[0216] From this state, the control unit 36 can implement the control methods illustrated in Figures 23 and 24.

[0217] In step 41, the activation control signal emitted by the activation button 51 is detected.

[0218] Step 42 switches the solenoid valve 48 to an open state by connecting the detection chamber 61 to the vacuum pump 37. This state can be indicated by turning on an indicator light 96 on the detection dome 55, such as a red LED, such as on the handle 76, as illustrated in fig. fifteen.

[0219] This creates suction in the detection chamber 61 . If the detection dome 55 is correctly positioned on the membrane, and the sealing lip 24 is in tight contact with the membrane 5, 8 around the entire periphery of the detection chamber 61, a reduced pressure is created that presses the detection dome 55 tightly against the membrane 5, 8, pressing down the sealing lip 24. Then, the gas coming from the detection chamber 61 can be analyzed as explained above.

[0220] In step 45, the deactivation control signal provided by the deactivation button 52 is detected.

[0221] At step 46, switch the solenoid valve 48 to the closed state to disconnect the detection chamber 61 from the vacuum pump 37. The reduced pressure in the detection chamber 61 is no longer maintained, resulting in an increase in pressure. However, in the absence of a major leak, pressure buildup can be very slow.

[0222] Therefore, at step 47, a vent is preferably opened to allow communication of the detection chamber 61 with the surrounding atmosphere, which allows the detection dome 55 to be instantly detached from the membrane 5, 8.

[0223] In one embodiment, steps 46 and 47 can be performed simultaneously by switching the three-way valve 148, shown schematically in FIG. 25, which is used in place of the solenoid valve 48 shown in FIG. 22.

[0224] The solenoid valve 48 may be located on the gas outlet 78 of the detection dome 55, as illustrated in FIG. 22. It may also be located elsewhere in the suction circuit, for example at the level of branch connector 38, as indicated by reference numeral 248.

[0225] The control signals between the control unit 36, the solenoid valve 48, the activation button 51 and the deactivation button 52 are transmitted via wired or wireless communication channels 35, for example, in the form of a flexible electrical cable or braided flexible cables to facilitate the mobility of the detection dome 55.

[0226] In one embodiment, the control unit 36 is also configured to control the analysis tool 56. To this end, a wired or wireless communication channel 35 is also provided between the control unit 36 and the analysis tool 56 . In addition, a pressure sensor 49 connected to the control unit 36 is also provided on the detection dome 55 to measure the pressure in the detection chamber 61 after step 42.

[0227] In this case, the control method performed after the activation control signal continues as follows.

[0228] In step 43, the pressure referred to in the measurement signal from the pressure sensor 49 is compared with a predetermined pressure threshold to enable the analysis tool 56 to operate. If the measured pressure is below the threshold, step 44 is performed. This condition may be indicated by turning on another indicator light on the detection dome 55, such as a green LED, such as on the handle 76, as indicated by reference numeral 97, in FIG. fifteen.

[0229] At step 44, the analysis tool 56 is activated to perform an analysis cycle to detect the leak rate, as explained above.

[0230] In the case of the detection dome according to the fourth embodiment illustrated in FIG. 13 or 21, two channels 82 and 50 extend through the main body to connect the detection chamber 61 to two gas outlets 78 and 50. A pressure sensor 49 may be located on the detection dome 55 and connected to the gas outlet 50 as illustrated in FIG. 22. Pressure sensor 49 may also be located elsewhere.

[0231] Through the control methods described above, and in particular through the use of the detection dome according to the fourth embodiment, the leak detection device 54 becomes particularly simple and fast.

[0232] The source of reduced pressure is activated in advance, the operator takes the detection dome 55 by the two handles and places the detection dome 55 in the selected test area, if applicable, using the sighting devices described above.

[0233] The operator then presses the activation button 51 . Next, the method shown in Fig. 23 until the analysis tool 56 obtains a measurement indicative of the leakage rate.

[0234] The operator only needs to press the deactivation button 52 to place the detection dome 55 in another inspection area. Therefore, the detection dome 55 can be used without operator interaction with the vacuum pump 37, the control unit 36 or the analysis tool 56 in the work area, determined by the length of the fluid and electrical connections of the detection dome 55 to these elements. To facilitate the mobility of the leak detection device 54 on a larger scale, the vacuum pump 37, the control unit 36 and the analysis tool 56 may be mounted on a movable cart, which is not illustrated.

[0235] In another embodiment, which is not shown, various features of the previous embodiments may be combined with each other. In fact, the mechanical pressing means 66 shown in FIG. 8, for example, can be adapted to the seal 60 shown in FIG. 5 by modifying the design of the curved strips 72.

[0236] The detection dome, the detection device, and the method of using the device described above are specifically for checking the tightness of the membrane of the sealed and thermally insulated membrane tank. For example, such membrane reservoirs are specifically described in patent applications WO14057221, FR2691520.

[0237] Membrane tanks have a plurality of walls that are of a sandwich construction, as shown in FIG. 11. Each wall 1 includes, in the direction from the outside to the inside of the tank, an auxiliary barrier 2, which includes auxiliary insulating panels 3, fixed on the supporting structure 4, an auxiliary membrane 5, based on the auxiliary barrier 2, the main barrier 6, including includes main insulating panels 7 resting on the auxiliary membrane 2 and fixed on the supporting structure 4 or on the auxiliary insulating panel 3, and the main membrane 8 resting on the main heat-insulating barrier 6 and intended for contact with the liquefied gas contained in the tank.

[0238] The reservoir has a generally multifaceted shape. In the embodiment illustrated in FIG. 12, the tank has a front wall 9 and a rear wall, which is not shown, which in this case are octagonal in shape. The tank also includes a top wall 10, a bottom wall 11 and side walls 12, 13, 14, 15, 16, 17 which extend in the longitudinal direction of the tank between the front wall 9 and the back wall.

[0239] The auxiliary heat-insulating barriers 2 of the tank walls are connected to each other so as to form an auxiliary sealed heat-insulating space between the supporting structure 4 and the auxiliary membrane 5. Likewise, the main heat-insulating barriers 6 of the walls of the tank are connected to each other so as to form between the auxiliary membrane 5 and the main membrane 8 the main sealed heat-insulating space.

[0240] The main membrane 8 and/or the auxiliary membrane 5 include a plurality of metal plates welded to each other. The method of leak testing, which will be described below, is directed, in particular, to testing the tightness of welds connecting metal plates to each other. According to one embodiment, the membrane to be tested has corrugations that allow it to deform under the thermal and mechanical loads imposed by the fluid stored in the reservoir. For this, as shown, for example, in Fig. 8, each metal plate includes two mutually perpendicular rows of corrugations.

[0241] In one embodiment, the leak test method includes three steps, where:

- carry out the diffusion of the indicator gas in the heat-insulating space, covered with a membrane 5, 8, the tightness of which is to be checked;

- monitor the spread of tracer gas in the heat-insulating space; and

- check the tightness of the welds of the membrane 5, 8.

[0242] In another embodiment, the leak test method includes only leak testing the membrane welds 5, 8 without using a tracer gas.

[0243] The step of spreading the tracer gas includes supplying the tracer gas to the heat-insulating space covered by the membrane 5, 8, the tightness of which is to be checked. When it is required to check the tightness of the auxiliary membrane 5, the tracer gas is supplied to the auxiliary heat-insulating space. In this case, the leak test method is carried out before the installation of the main heat barrier 7 and the main membrane 8. When the seal of the main membrane 8 is to be checked, the tracer gas is supplied to the main heat seal space.

[0244] FIG. 12 schematically illustrates a sealed and thermally insulated reservoir and a system for supplying tracer gas to the thermally insulated space.

[0245] The supply system includes a plurality of pipelines 18, which, on the one hand, are connected to a source of tracer gas, which is not illustrated, and, on the other hand, are connected to the tracer gas supply devices 19, forming channels for supplying tracer gas through the membrane 5, 8, the tightness of which needs to be checked. The tracer gas supply devices 19 in particular provide passages for the tracer gas supply through the membrane of the bottom wall 11. This arrangement is particularly advantageous because the tracer gas has a lower vapor density than air, whereby it rises in the heat-insulating space. Thus, the supply of tracer gas from below through the tested membrane 5, 8 of the lower wall 11 ensures rapid and uniform distribution of the tracer gas in the heat-insulating space.

[0246] In the embodiment shown in FIG. 12, the bottom wall 11 is equipped with at least four tracer gas supply devices 19 which are uniformly distributed over the surface of the bottom wall 11. The bottom wall 11 is rectangular in shape and can therefore be divided into four equal area zones by two x and y axes. symmetry. Each of the four indicator gas supply devices 19 is located in one of the above four zones. In the specific illustrated embodiment, each tracer gas supply device 19 is located near the center of the respective zone. In a specific embodiment, each of the four tracer gas supply devices is located at a distance (1/4)L from the adjacent longitudinal edge and at a distance (1/2)B from the adjacent transverse edge, where L is the longitudinal dimension of the bottom wall 11 and B is transverse dimension of the bottom wall 11.

[0247] The tracer gas spreading tracking step includes monitoring the tracer gas spreading in the heat-insulating space when the tracer gas has spread through the heat-insulating space.

[0248] To do this, samples are taken of the gas contained in the heat-insulating space, into which the indicator gas was supplied, using a plurality of gas sampling devices passing through the membrane covering said heat-insulating space. Each sampling device is connected to an analysis instrument, such as a mass spectrometer, which makes it possible to check the presence and concentration of tracer gas in the corresponding area of the thermal insulation space.

[0249] The step of checking the welds is to use the leak detection device 54 described above on one of the membranes 5, 8 of the sealed and insulated tank.

[0250] Although the invention has been described with reference to several specific embodiments, it is clear that it is not limited to them in any way, and that it includes all technical equivalents of the described means and combinations thereof, if they are within the scope of the invention.

[0251] The use of the verb "comprise" or "include" and derivative forms does not exclude the presence of elements or steps other than those mentioned in the claims.

[0252] In the claims, no reference position in parentheses should be interpreted as limiting the claims.

Claims (37)

1. Device (54) for detecting leaks for detecting leaks in the area (62) of checking the sealing membrane (5, 8) of a sealed and heat-insulating tank, containing leak detection dome (55), which includes a main body (100) designed to be placed in the test area (62), and a seal (60) connected to the main body (100) and configured to form a detection chamber (61) between the main body (100) and the test zone (62), wherein the seal (60) includes a peripheral sealing edge (64) configured to contact the sealing membrane and having a closed loop surrounding the detection chamber (61), a vacuum pump (57) connected to the detection chamber (61) to create a reduced pressure in the detection chamber (61), and an analysis tool (56) connected to the detection chamber (61) for analyzing the gas present in the detection chamber (61), in which the sealing lip (64) is configured to take two positions, namely, the first position in the initial state without creating a vacuum in the detection chamber (61) and the second position in working condition when creating a vacuum in the detection chamber (61), while sealing edge (64) only in the second position relative to the operating state contains a clamping section (53), which is clamped between the main body (100) and the sealing membrane (5, 8) at least in the area of the periphery of the detection chamber (61), and the sealing edge ( 64) has the flexibility to form said clamping portion (53) by deforming the sealing lip (64) towards the detection chamber (61) under reduced pressure in the detection chamber (61). 2. The device according to claim 1, in which the sealing lip (64) is configured to have at least in operation, in which the detection chamber (61) is underpressure, a clamping portion (53) that is clamped between the main body (100) and a sealing membrane (5, 8) around the entire periphery of the detection chamber (61). 3. Device according to any one of claims 1 and 2, wherein the detection chamber (61) of the leak detection dome (55) has a convex, for example round or polygonal, area (25) designed to cover the connection area between four corrugated or flat metal plates (31). 4. Device according to claim 3, in which the circle geometrically inscribed in the convex zone (25) has a diameter of more than 68 mm. 5. The device according to claim 3 or 4, wherein the detection dome has an elongated shape along the longitudinal axis, and the detection chamber (61) of the leak detection dome (55) includes an elongated zone (24) designed to cover the straight edge of the metal plate, while the convex zone (25) is located at one end of the elongated zone. 6. The apparatus of claim 5, wherein the bulge is a first bulge (25) and the leak detection dome (55) detection chamber (61) includes a second bulge located at an end of the elongated zone opposite the first bulge. (25) along the longitudinal axis. 7. The device according to claim 3 or 4, in which the detection dome has an elongated shape along the longitudinal axis, and the convex zone (25) forms the central section of the detection chamber (61) of the leak detection dome (55), while the detection chamber (61) includes into itself two elongated zones (24), extended from the convex zone in the direction from each other along the longitudinal axis. 8. Device according to claim 3, wherein the detection chamber (61) has a convex polygonal or circular shape. 9. The device according to claim 8, wherein the circle geometrically inscribed in the shape of the detection chamber has a diameter greater than 68 mm. 10. The device according to any one of claims 1 to 9, wherein the leak detection dome (55) includes a mechanical pressing means (66) mounted on the main body (100) and including at least one pressing element (72 ) configured to exert pressure on a portion of the sealing lip (64) in the direction of the membrane (5, 8) when the main body (100) is located in the test area (62). 11. Apparatus according to any one of claims 1 to 10, wherein the analysis tool (56) is configured to detect a tracer gas. 12. Apparatus according to any one of claims 1 to 10, wherein the analysis tool (56) is configured to detect an ambient air component. 13. A method of using the device (54) for detecting leaks according to any one of claims 3-12 in the zone (62) of the test, which includes the zone of connection between four corrugated or flat metal plates (31) of the sealing membrane (5, 8) of the tank and the method includes the steps of: a leak detection dome (55) is placed in the test zone (62) so that the sealing edge (64) is in contact with the sealing membrane along the entire periphery of the test zone (62), and the convex zone (25) covers the said connection zone, create a reduced pressure in the detection chamber (61) using a vacuum pump (57), clamping the clamping section of the sealing edge (64) between the main body (100) and the sealing membrane (5, 8) at least in the area of the periphery of the detection chamber (61), sending the gases present in the detection chamber (61) to the analysis tool (56), and analyze using the analysis tool (56) the gases coming from the detection chamber (61) to generate a measurement signal indicating the amount of at least one gas present in the detection chamber (61). 14. Leak detection method for detecting leakage in the test area of the sealing membrane of the tank using the leak detection dome, wherein the leak detection dome comprises a main body and a seal connected to the main body and configured to form a detection chamber between the main body and the sealing membrane, the seal includes a peripheral sealing edge configured to contact the sealing membrane and having a closed loop surrounding the chamber detection, wherein the leak detection dome further includes a mechanical pressure means mounted on the main body and including at least one pressure element configured to apply pressure to the sealing edge portion in the direction of the membrane when the main body is located in the test area , moreover, the detection dome contains a carrier element (73) attached to the main body (100), and the clamping element includes a body (89) attached to the carrier element (73), a rod (90) mounted for movement relative to the body (89), a spring (86) pushing the rod (90) towards the sealing lip (64), and a support element (91) attached to one end of the rod (90) and abutting against the sealing lip (64) under the action of the spring (86), said sealing membrane includes a plurality of corrugated or flat metal plates welded to each other, wherein the leak detection method includes the steps of: placing the detection dome on the sealing membrane so that the detection chamber is located at the level of at least one weld between the first metal plate and the second metal plate, and placing the clamping element in such a way that it exerts pressure on the area of the sealing edge, which crosses said weld, lower the pressure in the detection chamber using a vacuum pump, directing the gas phase contained in the detection chamber to an analysis instrument to detect the gas present in the detection chamber. 15. The method according to claim 14, wherein the detection chamber (61) of the leak detection dome (55) includes a convex zone (25), wherein said pressing element for exerting pressure on the portion of the sealing lip that intersects said weld is located on the periphery of the convex zone (25). 16. The method according to claim 15, in which the weld between the first metal plate and the second metal plate is the first weld, and the pressure element is the first pressure element, and in which the convex zone (25) of the detection chamber is also located at the level of the second a weld connecting the first or second metal plate (31) to the third metal plate, the mechanical clamping means additionally including a second clamping element located so as to exert pressure on the section of the sealing edge that intersects the said second weld. 17. The method according to claim 16, wherein the metal plates are substantially rectangular and the detection chamber is located at the level of the joint zone between the first, second, third metal plates and the fourth metal plate, and the joint zone further includes a third weld connecting a first or second metal plate (31) with a fourth metal plate, the mechanical pressing means further including a third pressing element positioned to exert pressure on a portion of the sealing lip that intersects said third weld. 18. The method according to any one of claims 14 to 17, wherein the detection dome has an elongated shape along the longitudinal axis, and the detection chamber (61) of the leak detection dome (55) includes an elongated zone (24) designed to cover a straight edge metal plate, while the convex zone (25) is located at one end of the elongated zone. 19. The method according to any one of claims 14-18, in which the rod is a first rod (90) and the clamping element includes a second rod (90) mounted for movement relative to the main body (100), and the first rod and the second rod (90) is located at a distance from each other, the springs (86) pushing said rods (90) in the direction of the sealing edge (64), and the support element, which is an elongated support element (91), has a first end attached to one end of the first rod (90), and the second end attached to one end of the second rod (90), and the said elongated support element (91) abuts against the sealing lip (64) under the action of the springs. 20. The method according to any one of claims 14 to 19, in which the clamping element (87) includes a plurality of adjusting elements (92) mounted on the main body (100) and forming a line, and the adjusting element (92) includes a rod (93) extending perpendicularly in the direction of the sealing lip (64), wherein the rod (93) has an end (94) whose position can be adjusted in the longitudinal direction of the rod so that it contacts the sealing lip. 21. The method according to claim 20, wherein the pressing element (87) further includes a distributing support plate (95) located between the ends (94) of the rods (93) and the sealing lip (64).

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