DEVICE AND METHOD FOR TESTING A SEAL

Description

technical field

[0001] The present invention relates to the field of sealing systems for fluid storage tanks as well as to the field of pipeline connection systems.

[0002] By way of non-limiting example, the invention can be implemented in a foam fire protection installation for a waste treatment plant.

[0003] The present invention relates more particularly to a device and a method for testing the leak tightness of such systems. Prior art

[0004] Many industrial installations, for example fire protection by foam projection, include a tank with a manhole that needs to be sealed airtight.

[0005] Prior art systems for sealing systems include a cover bolted to a mounting flange welded to the tank. The sealing of such a cover-flange assembly is typically ensured by a flat sealing gasket ( Fig. 1a ), toric ( Fig. 1b ) or even square in section ( Fig. 1c ).

[0006] We also know of joining systems in the prior art that allow pipes to be connected together.

[0007] To test the leak-tightness of such systems, the tank or pipes are filled with a test fluid (gas or liquid) and this test fluid is pressurized.

[0008] In the case of sealing systems, it is necessary to drill through the cover to fit it with a valve allowing the assembly to be pressurized, this drilling itself constituting an additional risk of leakage.

[0009] In the case of joint systems, it is necessary to plug the pipes.

[0010] When the sealed tank or pipes are filled with the pressurized test fluid, the pressure is checked to see if it decreases over time. The seal is considered satisfactory when no pressure loss is observed over time.

[0011] Such a testing procedure carries a risk of contaminating the fluid stored in the tank or conveyed through the pipelines, as well as contaminating the environment outside the installation. This can lead to health problems if the fluid is toxic. Furthermore, this testing procedure requires filling the entire system under test with the test fluid, which, in the case of large pipelines or tanks, necessitates a significant quantity of test fluid and therefore incurs additional costs for the operator.

[0012] One aim of the present invention is to remedy these drawbacks by providing a device and a leak testing method that limits or eliminates the risk of leakage and / or pollution.

[0013] US 2016 / 223426A1 describes a device for testing the leak tightness of a seal and includes a test section consisting of two plates between which the seal to be tested is clamped.

[0014] GB 2 237 393 A describes a leak test device for an installation of the type comprising a tank for storing a first fluid in an internal space of that tank or of the type comprising two pipes and a junction between those two pipes.

[0015] JP S58 198741 A describes a leak test device for an installation of the type comprising a tank intended to store a first fluid in an internal space of that tank. Description of the invention

[0016] Accordingly, the invention relates, according to claim 1, to a device for testing the leak tightness of an installation: of the type comprising a reservoir intended to store a first fluid in an internal space of that reservoir, or of the type comprising two pipes and a junction between those two pipes, those pipes being intended to transport a first fluid in an internal space of those pipes, This device comprises: a pressurization system arranged to pressurize a test fluid within the device, and a pressure measurement system arranged to measure the pressure of the test fluid within the device; this device further comprises: a pressurization chamber, and a first sealing element, for example an O-ring, arranged to isolate the pressurization chamber from said internal space; and: the pressurization system being arranged to pressurize the test fluid within the pressurization chamber, and the pressure measurement system being arranged to measure the pressure of the test fluid within the pressurization chamber; this device being characterized in that the pressurization chamber is annular and delimited by a mounting flange, and in that the device further comprises a cover and the mounting flange, the mounting flange being arranged on the tank to secure a cover to the tank.the fixing flange being arranged to fix the cover to the tank, the cover and the fixing flange being arranged to delimit the pressurization chamber, or in that the fixing flange is arranged on a pipe to form a junction with the fixing flange of a pipe, these fixing flanges being arranged to fix the two pipes together, and to delimit the pressurization chamber.

[0017] In one embodiment, the test fluid can be a liquid that limits the risk of explosion in case of leakage, for example water.

[0018] In one embodiment, the test fluid can be a gas such as air, for example compressed.

[0019] In one embodiment, the test fluid can be a gas containing helium. Since helium is a noble gas, it could thus facilitate the precise location of the leak.

[0020] In one embodiment, the pressure measurement system can be a direct reading manometer or an electronically reading piezometer.

[0021] Pressurization can therefore be achieved in a relatively small volume, that is to say much smaller than the volume of said interior space.

[0022] The invention therefore makes it possible to eliminate or reduce the risk of leakage and / or pollution / contamination of the first fluid stored in a tank or circulating in a pipeline.

[0023] The first sealing element can be an O-ring or a flat gasket or a square section gasket or any other type of gasket suitable for the dimensions, materials and pressures used or implemented.

[0024] Preferably, the device according to the invention may further comprise a second sealing element arranged to isolate the pressurization chamber from the outside of said installation.

[0025] This second sealing element provides an additional seal, independent of that provided by the first sealing element.

[0026] Preferably, the said first and second sealing elements can delimit the pressurization chamber.

[0027] According to a first embodiment, said installation includes a tank, the device according to the invention further includes a lid and the fixing flange, the lid being arranged to close the tank, the fixing flange being arranged to fix the lid to the tank, the lid and the fixing flange being arranged to delimit the pressurization chamber.

[0028] In an embodiment according to this first variant of the embodiment, the cover and / or the fixing flange may include a groove and the pressurization chamber may have a volume constituted by this groove.

[0029] According to a second embodiment, said installation may comprise two pipes and a junction between these two pipes, the device according to the invention further comprising one or more fixing flanges constituting said junction, these fixing flanges being arranged to: fix the two pipes together, and delimit the pressurization chamber.

[0030] According to the invention, the pressurization chamber is annular.

[0031] An annular pressurization chamber allows the use of annular gaskets as sealing elements. Annular gaskets are easier to machine than square or other shaped gaskets.

[0032] Alternatively, the pressurization chamber could be square or oval in shape, for example when using the device on a tank or pipes of such a shape.

[0033] According to claim 5, the invention also relates to a method for testing the leak-tightness of an installation: of the type comprising a reservoir intended to store a first fluid in an internal space of that reservoir, or of the type comprising two pipes and a junction between those two pipes, those pipes being intended to transport a first fluid in an internal space of those pipes, This method, implementing the device according to the invention and comprising: pressurization of the test fluid in the pressurization chamber using the pressurization system, measurement of the pressure of the test fluid in the pressurization chamber using the pressure measurement system.

[0034] The advantages conferred by such a process are similar to the advantages conferred by the device according to the invention. Description of figures and embodiments

[0035] Other advantages and features of the invention will become apparent upon reading the detailed description of implementations and embodiments, which are by no means limiting, and the following attached drawings: THE Figures 1a, 1b and 1c represent a prior art device comprising the following sealing elements: ∘ Figure 1a : flat joint, ∘ Figure 1b : O-ring, ∘ figure 1c : square section joint; the figure 2 represents a device according to the invention; the figure 3 represents a device fixing flange figure 2 ; there figure 4 represents a cover for the device figure 2 ; there Figure 5 represents a first type of installation equipped with a device according to the invention; the figure 6 represents a second type of installation equipped with a device according to the invention.

[0036] The embodiments described below are not exhaustive; variants of the invention may include, in particular, a selection of the described features, isolated from the other described features—even if this selection is isolated within a sentence containing these other features—if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection includes at least one feature, preferably a functional one without structural details, or with only a portion of the structural details if this portion alone is sufficient to confer a technical advantage or to differentiate the invention from the prior art. Prior art

[0037] THE Figures 1a, 1b and 1cshow a prior art leak test device for an installation of the type including a tank (not shown). More specifically, this prior art device includes: a cover 93 arranged to close the tank (not shown), a fixing flange 94 arranged to fix the cover 93 to the tank (not shown), a pressurization system 11 arranged to pressurize a test fluid in the tank via an orifice 931 made in the cover 93, a pressure measuring system 12 such as a manometer arranged to measure the pressure of the test fluid in the tank, via an orifice 932.

[0038] Typically, the mounting flange 94 is pressed into and then welded onto the tank (not shown). The cover 93 is attached to the flange 94 using screw-nut fasteners (not shown). Sealing is ensured by a sealing element, which may be a flat gasket 921 ( Fig. 1a), a 922 O-ring ( Fig. 1b ), or a 923 square section joint ( Fig. 1c ).

[0039] In these examples, the cover 93, the fixing flange 94 and the sealing element 921-923 are solids of revolution relative to an axis A1. First variant embodiment of the invention

[0040] There figure 2 shows a leak testing device according to the invention. This device can be mounted on the installation 70 illustrated in Figure 5 . This installation 70 is of the type comprising a tank 71 intended to store a first fluid 79 in an internal space 711 of this tank 71.

[0041] Similar to the prior art device, this device according to the invention comprises: a cover 3, 73 arranged to close the tank 71, a fixing flange 4, 74 arranged to fix the cover 3, 73 to the tank 71 - the flange 4, 74 is typically inset and then welded onto the tank 71, a pressurization system 11 arranged to pressurize a test fluid in the device ( Fig. 2 ) - the test fluid can be a gas such as compressed air or a liquid, a pressure measuring system 12, such as a manometer, arranged to measure the pressure of the test fluid in the device ( Fig. 2 ).

[0042] Unlike the prior art device, the device according to the invention further comprises: a pressurization chamber 20, and a first sealing element 21, for example an O-ring, arranged to isolate the pressurization chamber 20 from said internal space 711.

[0043] Furthermore, unlike the prior art device (compare Fig. 1a And Fig. 2 ) : The pressurization system 11 is arranged to pressurize the test fluid in the pressurization chamber 20, and the pressure measurement system 12 is arranged to measure the pressure of the test fluid in the pressurization chamber 20.

[0044] To pressurize the test fluid in the pressurization chamber 20, the pressurization system 11 is connected to the chamber 20 by an orifice 31 made in the cover 3, this orifice 31 opening onto the chamber 20 when the cover 3 is assembled to the fixing flange 4.

[0045] To measure the pressure of the test fluid in the pressurization chamber 20, the pressure measuring system 12 is connected to the chamber 20 by an orifice 32 made in the cover 3, this orifice 32 opening onto the chamber 20 when the cover 3 is assembled to the fixing flange 4.

[0046] In this example, ports 31 and 32 are distinct (see Figs. 2 and 4 ).

[0047] In an example embodiment not shown, the same orifice could be used to connect systems 11 and 12 to chamber 20.

[0048] With reference to the figure 2 , the cover 3 and the fixing flange 4 are arranged to delimit the pressurization chamber 20.

[0049] As the example of the figure 2 , the device according to the invention further includes a second sealing element 22 arranged to isolate the pressurization chamber 20 from the outside of said installation.

[0050] The second sealing element 22 is preferably an O-ring.

[0051] We see in figure 2 that the said first 21 and second 22 sealing elements also delimit the pressurization chamber 20.

[0052] Thus, the pressurization chamber is delimited: by the two sealing elements 21 and 22, by the cover 3, and by the fixing flange 4.

[0053] In this example, the mounting flange 4 includes a groove 41 (see Fig. 3 ). According to this arrangement, the pressurization chamber 20 has a volume constituted by this groove 41.

[0054] In embodiments not shown, a groove could be machined, alternatively or complementaryly, in the cover 3.

[0055] There figure 2 This schematically illustrates an assembly of the cover 3 and the mounting flange 4. In an actual implementation of the device, the cover 3 is tightened against the flange 4 using screw-nut fasteners (not shown). In the example of installation 70 of the Figure 5Twenty M30 threaded screws and nuts are used, to which a tightening torque of 308 Nm is applied. Tightening the cover 3 against the flange 4 causes the seals 21 and 22 to be crushed. After tightening, the volume 20 is therefore essentially formed by the groove 41 ( Fig. 3 ).

[0056] In this embodiment example, the cover 3, the flange 4, and the sealing elements 21, 22 are solids of revolution relative to an axis A1.

[0057] In this example of an embodiment, the pressurization chamber 20 is annular.

[0058] Chamber 20 further defines a ring with axis A1.

[0059] There Figure 5 shows a foam fire protection installation.

[0060] This installation includes a tank 75 in which the reservoir 71 is embedded.

[0061] Tank 75 typically has a capacity of 12000 litres and contains a liquid 759 such as water.

[0062] The tank 71, called the emulsifier tank, typically has a capacity of 300 litres and the first fluid 79 it contains is a foaming product.

[0063] The cover 73 includes an inlet 736 arranged to introduce compressed air into the reservoir 71.

[0064] A gooseneck conduit 76 allows the foaming product to be conveyed from the reservoir 71 to the tank 75 when the internal space 711 of the reservoir 71 is pressurized after the introduction of compressed air through the inlet 736.

[0065] Typically, when the pressure in tank 75 exceeds a predetermined pressure threshold, for example 0.7 MPa, a valve 77 is opened to spread the mixture of water and foaming agent onto a fire.

[0066] We can see that the pressurization of the reservoir 71 results in a subsequent pressurization of the tank 75 via the conduit 76.

[0067] Therefore, performing a leak test according to the prior art would be problematic because the internal space 711 of the tank 71 would be pressurized. This would result in the foaming agent being displaced from the tank 71 to the vessel 75. Currently, this problem is addressed by installing a pump to control the transfer of the foaming agent from the tank 71 to the vessel 75 and prevent such a transfer during the leak test. However, such a pump doubles the installation cost and entails additional maintenance.

[0068] Conversely, the leak test device according to the invention makes it possible not to pressurize the internal space 711 of the tank 71 and thus remedies the various disadvantages of the prior art. Second embodiment of the invention

[0069] There figure 6 shows another installation 80 implementing a device according to the invention.

[0070] This installation 80 is of the type comprising two pipes 81 and 82. Pipe 81 is represented in radial longitudinal section so as to show an internal space 811 of these pipes.

[0071] These pipes 81 and 82 are intended to transport a first fluid 89, typically a liquid such as water, into said internal space 811 of these pipes.

[0072] Installation 80 includes a junction 83 between the two pipes 81 and 82.

[0073] More specifically, in this example, the junction 83 is made up of two fixing flanges 831 and 832.

[0074] The mounting flange 831 is embedded and welded to the pipe 81: this flange is also shown in radial longitudinal section in figure 6 The fixing flange 832 is embedded and welded to the pipe 82.

[0075] The fixing flanges 831 and 832 are arranged to fix the two pipes 81 and 82 together, with screw-nut type fixing means (not shown).

[0076] The leak testing device implemented in installation 80 of the figure 6 is equivalent to the device of the figure 2 : the flange 831 of the device of the figure 6 corresponds to flange 4 of the device figure 2 ; the 81 pipe of the device figure 6 corresponds to the reservoir on which flange 4 of the device can be mounted figure 2 ; the assembly consisting of the flange 832 and the pipe 82 of the device of the figure 6 corresponds to cover 3 of the device figure 2 .

[0077] Therefore, all embodiments described above with reference to figures 2 to 5 apply mutatis mutandis to the variant implementation of the figure 6 particularly with regard to: the pressurization system (not shown in Fig. 6 ), the pressure measurement system (not shown in Fig. 6 ), the pressurization chamber 820, the sealing elements 821 and 822.

[0078] In particular, in this example, the fixing flanges 831 and 832 are arranged to delimit the pressurization chamber 820. The pressurization chamber 820 is therefore delimited by the two sealing elements 821 and 822 and by the fixing flanges 831 and 832. Leak test procedure

[0079] The invention also relates to a method for testing the leak tightness of an installation according to the first or second embodiment described above.

[0080] The process involves implementing the following steps: pressurization of the test fluid in the pressurization chamber 20, 820 using the pressurization system 11; typically, the test fluid is compressed air and the pressurization chamber is brought to a predetermined pressure; in the installation 70 of the Figure 5 , this predetermined pressure is typically less than or equal to 0.7 MPa; a measurement of the pressure of the test fluid in the pressurization chamber 20, 820 using the pressure measuring system 12, typically a manometer.

[0081] When the predetermined pressure is reached, a test fluid inlet valve (not shown) is closed - the test fluid can therefore no longer exit the pressurization chamber 20 through the orifice 31.

[0082] After a predetermined period, typically more than ten minutes, preferably thirty minutes, the pressure measured by the manometer is checked.

[0083] If the pressure thus controlled is identical to the initially predetermined pressure reached, the sealing can be judged satisfactory.

[0084] In the event of a pressure drop, the sealing may be deemed unsatisfactory and a new disassembly-reassembly operation of the device may be carried out, replacing the seals.

[0085] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. For example, the sealing elements 21, 22, 821, 822 can be flat or square-section gaskets. Furthermore, the various features, shapes, variations, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive.

Claims

1. A device for testing the sealing of an installation (70, 80): - of the type comprising a tank (71) intended to store a first fluid (79) in an interior space (711) of this tank, or - of the type comprising two pipes (81, 82) and a junction (83) between these two pipes, these pipes being intended to transport a first fluid (89) in an interior space (811) of these pipes, this device comprising: - a pressurisation system (11) arranged to pressurise a test fluid in the device, and - a pressure measuring system (12) arranged to measure the pressure of the test fluid in the device, this device further comprising: - a pressurisation chamber (20), and - a first sealing element (21) arranged to isolate the pressurisation chamber (20) from said interior space (711, 811), the pressurisation system (11) being arranged to pressurise the test fluid in the pressurisation chamber (20), and the pressure measuring system (12) being arranged to measure the pressure of the test fluid in the pressurisation chamber (20), being characterised in that the pressurisation chamber (20) is annular and delimited by a fixing flange, and in that the device further comprises a cover (3, 73) and the fixing flange (4, 74), the fixing flange being arranged on the tank to fix a cover (3, 73) to the tank (71), the fixing flange (4, 74) being arranged to fix the cover (3, 73) to the tank (71), the cover (3, 73) and the fixing flange (4, 74) being arranged to delimit the pressurisation chamber (20), or in that the fixing flange is arranged on a pipe to form a junction with the fixing flange of a pipe, these fixing flanges (831, 832) being arranged to fix the two pipes (81, 82) together, and to delimit the pressurisation chamber (20).

2. The device according to claim 1, characterised in that it further comprises a second sealing element (22) arranged to isolate the pressurisation chamber (20) from the outside of said installation.

3. The device according to claim 2, characterised in that said first (21) and second (22) sealing elements delimit the pressurisation chamber (20).

4. The device according to any one of claims 1 to 3, said installation comprising a tank (71), this device being characterised in that it further comprises a cover (3, 73) and a fixing flange (4, 74), the cover (3, 73) being arranged to close the tank (71), the fixing flange (4, 74) being arranged to fix the cover (3, 73) to the tank (71), the cover (3, 73) and the fixing flange (4, 74) being arranged to delimit the pressurisation chamber (20) .

5. The device according to claim 4, characterised in that the cover (3, 73) and / or the fixing flange (4, 74) comprise a groove (41) and in that the pressurisation chamber (20) has a volume constituted by this groove (41) .

6. The device according to any one of claims 1 to 3, said installation comprising two pipes (81, 82) and a junction (83) between these two pipes, this device being characterised in that it further comprises one or more fixing flanges (831, 832) constituting said junction (83), these fixing flanges (831, 832) being arranged to: - fix the two pipes together (81, 82), and - delimit the pressurisation chamber (20).

7. The device according to any one of the preceding claims, characterised in that the pressurisation chamber (20) is annular.

8. A method for testing the sealing of an installation (70, 80): - of the type comprising a tank (71) intended to store a first fluid (79) in an interior space (711) of this tank, or - of the type comprising two pipes (81, 82) and a junction (83) between these two pipes, these pipes being intended to transport a first fluid (89) in an interior space (811) of these pipes, this method implementing a device according to any one of the preceding claims and comprising: - pressurising the test fluid in the pressurisation chamber (20) using the pressurisation system (11), - measuring the pressure of the test fluid in the pressurisation chamber (20) using the pressure measuring system (12).