RUPTURE DISC FOR A DEVICE FOR PROTECTING AGAINST OVERPRESSURES INSIDE A DEVICE, USE IN AN APPARATUS INTENDED FOR CONSECUTIVELY CONTAINING TWO GASES OF SEPARATE CHEMICAL NATURE

Abstract

The invention relates to a rupture disc for a device for protecting against overpressures inside an apparatus, the disc consisting of a generally circular part including two planar surfaces substantially parallel to one another, and two notches each located along a circumference, the circumferences of the two notches being different from one another, the notch located on the larger circumference being made on one of the planar surfaces, referred to as lower surface, while the notch located on the smaller circumference is made on the other one of the planar surfaces, referred to as upper surface.

Claims

1-19. (canceled)

20. A rupture disk for a device for protecting against overpressure inside an apparatus, the disk consisting of a part of generally circular form comprising two planar faces substantially parallel to one another, and two scores each located on a circumference, wherein the circumferences of the two scores are different from one another, the score located on the larger circumference being produced on one of the planar faces, called bottom face, whereas the score located on the smaller circumference is produced on the other of the planar faces, called top face.

21. The rupture disk as claimed in claim 20, wherein the score located on the top face is designed to rupture at a first pressure P0 whereas the score located on the bottom face is designed to rupture at a second pressure P1 different from P0.

22. The rupture disk as claimed in claim 20, one and/or the other of the scores being continuous over its circumference.

23. The rupture disk as claimed in claim 20, one and/or the other of the scores being discontinuous on its circumference.

24. The rupture disk as claimed in claim 20, wherein the circumferences of the two scores are concentric to one another.

25. The rupture disk as claimed in claim 20, wherein the circumferences of the two scores are centered on the center of the circular part.

26. The rupture disk as claimed in claim 20, wherein the part is made of a steel chosen from the ferritic, martensitic, ferrito-bainitic, bainitic, ferrito martensitic, ferrito-perlitic, and perlitic steels.

27. The rupture disk as claimed in claim 20, wherein the part has a thickness of 1 to 5 mm.

28. The rupture disk as claimed in claim 20, wherein the depth of the scores is less than or equal to a value corresponding to approximately 70% of the thickness of the part.

29. The rupture disk as claimed in claim 20, wherein the radius at the bottom of the scores is between 0.1 and 0.6 mm.

30. The rupture disk as claimed in claim 20, wherein the aperture angle of the scores is less than or equal to 500.

31. An apparatus, intended to contain, in succession, two gases of different chemical nature, comprising: a wall in which an aperture is formed; a device for protecting the apparatus against overpressures comprising: a rupture disk as claimed in claim 20, the bottom face of which is in direct contact with the pressure contained in the apparatus, at least one bearing element, designed to press the disk against the wall with the scores of the disk over the aperture.

32. The apparatus as claimed in claim 31, wherein the protection device comprises: sealing means arranged between the periphery of the disk and the wall around the aperture, at least one holding element, called closing cap, bearing against the bearing element, and fixed by tightening to the apparatus so as to hold the bearing element and the rupture disk on the apparatus and ensure the seal at the level of the sealing means.

33. The apparatus as claimed in claim 31, wherein the bearing element is a ring whose bottom face bears against the top face of the disk and whose aperture is arranged facing the aperture of the wall.

34. The apparatus as claimed in claim 31, further comprising sealing means arranged between the periphery of the ring and the closing cap.

35. The apparatus as claimed in claim 34, the sealing means consisting of one or more O-ring seals.

36. The apparatus as claimed in claim 32, wherein the closing cap and the apparatus is pierced respectively with tapped holes facing one another to house the screws for tightening the closing cap on the apparatus.

37. A method comprising containing under pressure, two gases of different chemical nature, by the apparatus as claimed in claim 31.

38. The method as claimed in claim 37, wherein the apparatus is a hydrogen production and storage apparatus.

Description

DETAILED DESCRIPTION

[0064] Other advantages and features of the invention will emerge more clearly on reading the detailed description of the invention given in an illustrative and nonlimiting manner with reference to the following figures in which:

[0065] FIG. 1 is a view of a face of an exemplary rupture disk according to the invention,

[0066] FIG. 2 is a view of the opposite face of the rupture disk according to FIG. 1,

[0067] FIG. 2A is a view in longitudinal cross section of the rupture disk according to FIGS. 1 and 2,

[0068] FIG. 3 is a perspective view of an exemplary bearing ring according to the invention, designed to press the rupture disk of FIGS. 1 to 2A against a wall around an aperture of an apparatus under pressure to be protected,

[0069] FIG. 3A is a front view of the bearing ring according to FIG. 3,

[0070] FIG. 3B is a view in longitudinal cross section of the bearing ring according to FIGS. 3 and 3A,

[0071] FIGS. 4A and 4B are perspective and partial cross-sectional views of an apparatus under pressure onto which is fixed a protection device comprising the rupture disk and the bearing ring according to the invention,

[0072] FIG. 5 is a schematic view in longitudinal cross section of a rupture disk with a bearing ring according to the invention, showing the action of an overpressurized gas on the disk during validation tests,

[0073] FIGS. 6A and 6B are photographic reproductions of a rupture disk according to the invention having ruptured under a given pressure of helium, respectively seen from the side of the bottom face and of the top face,

[0074] FIGS. 7A and 7B are photographic reproductions of a rupture disk according to the invention having ruptured under a given pressure of hydrogen, respectively seen from the side of the bottom face and of the top face.

[0075] As illustrated in FIGS. 1 to 2A, the rupture disk 1 according to the invention is a circular part of diameter Ø whose planar face 10 is scored with a continuous score 12 of circular form C1, of aperture angle α1, of score bottom radius R1 and of score depth e1.

[0076] The other planar face 11 of the disk 1 is also scored with a continuous score 13 of circular form C2, of aperture angle α2, of score bottom radius R2 and of score depth e2.

[0077] The circumferences C1, C2 of the two scores 12, 13 are concentric and with a center that coincides with that of the disk 1.

[0078] As an example, the dimensions are as follows: [0079] thickness of the disk e1+e2: 1.5 mm, diameter Ø: 58 mm. [0080] diameter C1: 18 mm, depth e1: 0.65 mm, bottom radius R1: 0.1 mm, aperture α1 of 30°. [0081] diameter C2: 12 mm, depth e2: 0.85 mm, bottom radius R2: 0.1 mm, aperture α2 of 30°.

[0082] The disk 1 can advantageously be made of ferrito-perlitic steel for a use with hydrogen.

[0083] The constituent material of the ring can be a steel of any microstructure.

[0084] FIGS. 3 to 3B show a bearing ring 2 designed to press the rupture disk 1 according to the invention against a wall of an apparatus under pressure to be protected.

[0085] This ring 2 is of circular section with a diameter Ø2, a thickness H2 and comprises a top face 20 and a bottom face 21. This bottom face 21 defines the plane making it possible to hold the top face 11 of the disk 1.

[0086] The top face 20 is provided with a peripheral groove 22, of rectangular section of height H22 and of width L22. This groove 22 can house a sealing O-ring seal 6 designed to produce the final seal of the apparatus protection device as detailed hereinbelow.

[0087] The ring 2 is pierced with a central aperture 23 also of circular section 23 of diameter Ø23 over most of its height H23, a connection in the form of a radius of curvature r23 being produced at the join with the bottom face 21. The diameter Ø23 and the radius of curvature r23 are to be dimensioned according to the rupture pressures desired for the disk under inert gas and under hydrogen.

[0088] As an example, the dimensions are as follows: [0089] ring diameter Ø2: 58 mm, thickness H2: 9.25 mm, [0090] groove width L22: 4 mm, groove height H22: 2.4 mm, groove outer diameter Ø22: 45 mm [0091] diameter of the central aperture Ø23: 22.5 mm, height H23: 7.75 mm, radius of curvature r23: 1.5 mm.

[0092] The ring 2 is made of type 316L stainless austenitic steel preferably with its surface nitrided. This surface treatment makes it possible to harden the steel at the surface and thus ensure that, in case of rupture of the disk 1, the ring 2 will not be damaged.

[0093] Other materials may be considered for the production of the ring 2. Whatever the material considered for the ring, it is chosen such that the mechanical strength of the ring 2 is greater than that of the disk 1, that is to say that, at a given pressure, the disk 1 is deformed and under no circumstances the ring 2.

[0094] FIGS. 4A and 4B show an example of fixing of a protection device 4 incorporating the rupture disk 1 and the ring 2 according to the invention, to an apparatus 5 intended to contain, successively, two gases of different chemical nature, namely helium and hydrogen.

[0095] A wall of the apparatus 5 is pierced with a circular aperture 50 over which the bottom face 10 of the disk is positioned and held. The bottom face 10 with its score 12 is therefore in direct contact with the pressure inside the apparatus 5.

[0096] The top face 11 of the disk 1 is held against the wall of the apparatus 5 around the aperture 50 by the ring 2. More specifically, the peripheral part 14 of the disk is embedded between the wall of the apparatus 5 and the ring 2 whereas the scores 12, 13 are centered on the aperture 50 of the wall and the central aperture 20 of the ring 2.

[0097] The disk 1 and the ring 2 are held in place on the apparatus 5 to be protected by a closing cap 3 screwed into the wall of the apparatus. The closing cap 5, also of generally circular form, comprises a central aperture 30 positioned facing the central aperture 20 of the ring 2.

[0098] Although not represented, the tightening screws are screwed into the tapped holes 31, 51 respectively produced in the closing cap 3 and the wall of the apparatus 5.

[0099] The seal between the interior of the apparatus 5 and the exterior is produced via two O-ring seals 6.

[0100] One of the seals 6 is positioned between the apparatus 5 under pressure and the rupture disk 1. As illustrated in FIGS. 4A and 4B, this seal 6 may be housed in a groove 52 provided for this purpose in the wall of the apparatus 5.

[0101] The other of the seals 6 is positioned between the ring 2 and the closing cap 3. It is not essential to provide this other seal 6. If it proves necessary not to have any gas leak between the cap 3 and the ring 2, then installation of this other seal 6 between these two elements 2, 3 is vital. Such is the case for example if the apparatus 5 is located inside a building/structure/installation and if the gas must then be channeled in a pipe to be discharged outside.

[0102] On the other hand, if for example the apparatus 5 is located outdoors, then the installation of this other seal 6 is not vital. Such is the case for example when the apparatus 5 is a gas storage tank placed in the open air. As illustrated in FIGS. 4A and 4B, this other seal 6 may be housed in the groove 22 of the ring 2.

[0103] The seals 6 may be of elastomer. Advantageously, if the apparatus 5 is designed to remain for long periods under hydrogen pressure, at least the seal 6 between the rupture disk 1 and the apparatus 5 is made of indium.

[0104] The tightening torque applied to the closing cap 3 makes it possible to ensure both that the protection device 4 is held against the apparatus 5 and that the seals 6 are tight.

[0105] The inventors carried out validation tests on a protection device 4 according to the invention. It is specified here that, for these validation tests, the dimensions of the rupture disk 1 and of the ring 2 are those given by way of examples above. It is also specified that, for these validation tests, the rupture disk 1 was made of API X80 grade ferrito-perlitic steel and the ring 2 was made of 316L steel with its surface nitrided.

[0106] The device 4 was validated by using a disk bursting cell, a test means originally developed by the applicant in its research center located in Valduc. The test scheme in this bursting cell is shown in FIG. 5.

[0107] An increasing helium pressure with a rise in pressure rate of 20 bar/min, was applied under the disk 1 until its rupture. Three tests were carried out in succession on three different disks.

[0108] Then, three new tests were performed under an increasing hydrogen pressure (99.9999% pure) on three different disks.

[0109] The results of the tests are presented in the table below.

TABLE-US-00001 TABLE Rupture pressure Gas P.sub.R(bar) Location of the Rupture Helium 487 Score 13 500 516 Hydrogen 335 Score 12 296 392

[0110] In this table, it emerges that the rupture pressure of the disk 1 under hydrogen is systematically significantly lower, by approximately 30%, than that observed under helium.

[0111] Furthermore, under helium it occurs on the top score 13, whereas under hydrogen, the rupture always occurs at the bottom score 12. That is shown respectively in FIGS. 6A and 6B for the rupture under helium and in FIGS. 7A and 7B for the rupture under hydrogen, where the difference in size of the torn cappings 15 can be seen.

[0112] Two additional tests were carried out under hydrogen in order to confirm that the preceding test results are independent of the rate of pressure rise of the gas. Thus, the two additional tests were as follows: [0113] a first test was carried out at 6.7×10.sup.−2 bar/min. The results are comparable to those obtained under hydrogen at 20 bar/min. [0114] a second test was carried out at 2400 bar/min. The results of the test are also comparable to those obtained under hydrogen at 20 bar/min.

[0115] In conclusion, the protection device 4 according to the invention described above therefore does indeed make it possible to accommodate the maximum allowable pressure in the pressurized enclosure as a function of the nature of the gas contained, i.e. inert gas or hydrogen.

[0116] The apparatus 5 intended to be protected by the protection device 4 may advantageously be an apparatus used in the field of hydrogen energy production and storage.

[0117] Other variants and enhancements may be implemented without in any way departing from the scope of the invention which has just been described.

[0118] According to a preferred use, an apparatus with a rupture disk according to the invention as overpressurization protection device is designed to successively contain helium (He) and hydrogen (H.sub.2).

[0119] However, an apparatus with a rupture disk according to the invention may be used advantageously to contain all other existing inert gases.

[0120] In particular, it may be used with all the gases containing a partial H.sub.2 pressure.