Flame arrester device including a depressurization device

Abstract

Flame arrester device (1) comprising a hollow box (13), a filter (11) and a depressurization device which comprises at least one explosion panel (2) comprising a sheet (21) called a rupture sheet provided with a weakening zone, the box (13) having inside two opposite faces, one of which carries the explosion panel (2), characterized in that the weakening zone is arranged so as to draw in the sheet at least two parts which are intended to constitute respectively at least two leaves (3A, 3B) in the event of rupture of the sheet. Fig. 3

Description

Title of the invention: Flame arrester device comprising a depressurization device

[0001] The invention relates to a flame arrester device incorporating a depressurization device which comprises at least one explosion panel.

[0002] A flame arrester device is intended to be fixed to all storage enclosures without limitation, such as silos, hoppers, dryers, tanks, filtration systems, bucket elevators, etc., or to be fixed to material processing machines. These enclosures store powdery products or gases which, under certain conditions, are likely to cause an increase in pressure and temperature inside the enclosure, which may lead to an explosion and possibly to the release of flames.

[0003] Also, a flame arrester device incorporates a depressurization device which comprises an explosion panel capable of tearing in its weakened zone in the event of abnormal overpressure in the enclosure, the pressurized gas and possibly the flames then escaping through the tear hole in the panel. As for the flame arrester device, it comprises a hollow volume and a filter which surround the explosion panel. When this panel tears, the flame arrester device protects the environment from flames and burnt dust coming from the enclosure by stopping them via its filter. The flame arrester device also aims to weaken the pressure wave and reduce high temperatures.

[0004] The flame arrester device may have various geometries, for example parallelepipedal in shape, cylindrical in shape with a circular cross-section, or a truncated trapezoidal prism in shape combined with a semi-cylindrical volume, while the explosion panel which is associated with the base of the hollow volume of the flame arrester device has a generally rectangular or circular shape. The hollow volume of the flame arrester device must be large enough to allow the explosion panel to fully deploy perpendicularly under the impulse of the pressure forces. It is therefore necessary for the explosion panel to open correctly that the hollow space of the flame arrester device be at least slightly larger than the width of the panel when it is rectangular or the diameter of the panel disc when it is circular.

[0005] As a result, these flame arresters are bulky. However, it is always desirable to reduce their size as much as possible.

[0006] The aim of the invention is to propose a flame arrester device incorporating a depressurization device, the size of which is minimized.

[0007] The invention relates to a flame arrester device comprising a hollow box, a filter and a depressurization device (attached by removable fixing) which comprises at least one explosion panel comprising a so-called rupture sheet provided with a weakening zone, the box having inside two opposite faces, one of which carries the explosion panel, the flame arrester device being characterized in that the weakening zone of the sheet of the explosion panel is arranged so as to draw in the sheet at least two parts which are intended to constitute respectively at least two (distinct) leaves in the event of rupture of the weakening zone and therefore opening of the panel.

[0008] Thus, by the very design of the depressurization device according to an appropriate arrangement of the weakening zone, it is possible to reduce the size of a flame arrester device incorporating such a depressurization device. Indeed, the panel of the depressurization device no longer opens according to a single leaf (in a single piece) which would correspond to the entire width of the rupture sheet for a rectangular sheet or to the entire diameter of the sheet for a circular sheet, but opens according to at least two leaves reducing the deployment dimension to the perpendicular, in particular reducing according to half the width or the diameter of the sheet, while providing the same opening surface and therefore depression for the depressurization device.The distance between the depressurization device and the opposite face of the flame arrester box therefore no longer needs to be as great as in the case of existing flame arresters, which results in a much more compact flame arrester of the invention.

[0009] Furthermore, it is then no longer essential to have a dome shape for the flame arrester device above the depressurization device, but a flat shape is sufficient, which also makes it possible to lower the center of gravity of the flame arrester device.

[0010] In one embodiment, the weakening zone is arranged so as to form two parts of identical shapes which are intended to constitute two leaves of identical surface area.

[0011] Advantageously, the distance separating the sheet from the opposite face of the box has a dimension which corresponds to the correct passage of the leaves. By "which corresponds to the correct passage" is meant a size which is just necessary to allow the leaves to pass without friction.

[0012] According to one characteristic, the leaves open face to face or open back to back.

[0013] According to an exemplary embodiment of the weakening zone, the latter extends in a general H shape when viewed from above, in particular along a median line of the panel, which is the line of greatest direction when the panel is shaped rectangular, and according to two pairs of peripheral lines (parallel to each other) which start perpendicularly in two opposite directions from the center line, so as to draw said at least two parts which are intended to constitute leaves respectively. This arrangement of the weakening zone makes it possible in particular to open the panel according to two leaves facing each other and half the width of the rupture sheet. This therefore saves a lot of space compared to existing flame arrester devices, by reducing at least by half the size separating the explosion panel from the opposite face of the box of the flame arrester device.In this embodiment, the panel comprises in particular sealing means opposite the weakening zone, which are such that they comprise, on the one hand, a seal which is integral with a plate fixed astride the center line of the sheet, the seal being sandwiched between the sheet and the plate, and the plate having a weakening line opposite the weakening line of the sheet, and on the other hand, a seal which is arranged astride the peripheral lines on the face of the sheet opposite that facing the inside of the box. Alternatively, the seal opposite and covering the center line of the weakening zone, could be integral with a plate (at the longitudinal end of the plate) which would be fixed only on one of the two parts of the sheet, part intended to constitute one of the leaves.

[0014] According to another embodiment of the weakening zone, the panel being rectangular or square in shape, the weakening zone extends at the periphery of the sheet along two lines of general U-shape, each of the U's having a main branch parallel to one of the sides, which is the side of larger dimension when the panel is rectangular in shape, and two parallel and facing lateral branches extending perpendicularly from the ends of the main branch, the openings of the U's being facing each other and the pair of two lateral branches of one U being directed towards the other pair of branches of the other U without joining, so as to draw said at least two parts which are intended to constitute leaves respectively. The two U's do not join to provide a solid zone which will provide a hinge-function zone for folding the two parts when they are deployed.

[0015] According to yet another example of embodiment of the weakening zone, the panel being of circular shape, the weakening zone extends at the periphery of the sheet along two arcs of a circle with an angle close to 180° without joining so as to draw said at least two parts which are intended to constitute leaves. The two arcs of a circle do not join in order to provide a solid central zone with a hinge function for folding the two parts when they are deployed.

[0016] In the examples of embodiment of the circular panel or of the panel with the weakening zone arranged in a double U opposite, the panel can advantageously have a stop surface which extends perpendicular to the panel and is located in the middle part of the panel, preferably fixed both (and oppositely) to the sheet and to the box of the flame arrester device, and intended to constitute a surface limiting the opening angle of the panel leaves (so that they do not collide when deployed).

[0017] According to another characteristic, the explosion panel comprises sealing means opposite the weakening zone, in particular the sealing means comprising a seal which is arranged astride the weakening zone of the face of the sheet which is opposite the face facing the inside of the box. This seal corresponds to the peripheral sealing seal for fixing by bolting the flame arrester device.

[0018] The present invention is now described using examples which are solely illustrative and in no way limitative of the scope of the invention, and from the attached illustrations, in which: - [Fig.l] represents a perspective and bottom view of an example of a flame arrester device according to the invention integrating a depressurization device in the form of an explosion panel. - [Fig.2] corresponds to the top view of the flame arrester device of [Fig.l]. - [Fig.3] is a schematic sectional view of the flame arrester device of [Fig.l] showing in dotted lines the opening of the explosion panel according to two facing leaves. - [Fig.4] represents a schematic perspective view from above of the explosion panel of [Fig.l] in the closed position, illustrating the weakened zone of the panel. - [Fig.5] is a schematic view corresponding to [Fig.4] in the open position of the explosion panel. - [Fig.6] illustrates a perspective view from above of the panel of [Fig.l] according to an exemplary embodiment with regard to the fixing of the sealing means opposite the weakened zone. - [Fig.7] corresponds to the example of the panel in [Fig.6] in the open position and showing part of the sealing means. - [Fig.8] is a schematic cross-sectional view of [Fig.6] along the width of the panel. - [Fig.9] illustrates a schematic perspective view from above of another example of an arrangement of the weakening zone of a rectangular explosion panel, the panel further comprising a surface for limiting the opening angle of the leaves. - [Fig. 10] is a schematic view from below of the explosion panel of [Fig.9], provided with sealing means under the weakened zone. - [Fig. 11] corresponds to [Fig.9] in the open position of the panel, the leaves having deployed while being stopped by the opening limiting surface. - [Fig. 12] is a schematic sectional view of a flame arrester device incorporating the example of the explosion panel of [Fig.9] and showing in dotted lines the opening of the explosion panel according to two back-to-back leaves. - [Fig. 13] illustrates a schematic perspective view from above of yet another example of an arrangement of the weakening zone of an explosion panel which is here circular in shape, the panel also preferably comprising a surface for limiting the opening angle of the leaves. - [Fig. 14] corresponds to [Fig. 13] in the open position of the panel showing two deployed leaves. - [Fig. 15] is a schematic sectional view of a flame arrester incorporating the example of the explosion panel of [Fig. 13] and showing in dotted lines the opening of the explosion panel according to two back-to-back leaves.

[0019] The flame arrester device 1 illustrated in Figures 1 to 3, 12 and 15 incorporates a depressurization device in the form of at least one explosion panel 2. The flame arrester device 1 is intended to be fixed to an enclosure to be protected in the event of overpressure and explosion. The explosion panel 2 is intended to seal an orifice of the enclosure in a sealed manner and the flame arrester device 1 is intended to be positioned above the explosion panel 2, the explosion panel 2 and the flame arrester device 1 preferably being fixed concomitantly around the orifice of the enclosure. The explosion panel 2 is intended to tear in the event of abnormal overpressure in the enclosure, while the flame arrester device 1 arranged extending in height around the explosion panel 2 protects the external environment in the event of an explosion, by having a flame arrester function and a dust barrier and heat evacuation function.In order to break appropriately, the explosion panel comprises a weakening zone 3. According to the invention, the weakening zone 3 is arranged in a particular manner so as to form at least two parts 3A and 3B which are intended to constitute respectively at least two leaves in the event of rupture of said weakening zone. This configuration of the explosion panel 2 provides a compact flame arrester device 1.

[0020] The flame arrester device 1, more particularly visible in Figures 1 to 3, comprises a frame body 10, a flame arrester filter 11, and a protective grid 12, the flame arrester device being closed over its entire volume in the position of use. The filter part 11 and the grid 12 here have a rectangular shape in top view. The body 10 comprises a base or a box 13 of peripheral wall closed 14 and two openings (faces) (in particular parallel) opposite called upper and lower of respective planes P and P'. The box 13 supports at its upper opening or plane P, the filter 11 and the grid 12 above the filter, and carries, at its lower opening or plane P' on its peripheral base 15, the explosion panel 2. The box 13 delimits a hollow interior space or volume V between the plane P' corresponding to the bottom consisting of the explosion panel 2 and the plane P, the face opposite the panel, as well as with the peripheral wall 14. The box 13 has here by way of example a volume shape whose section is trapezoidal, the peripheral wall 14 widening from the base 15 to the level of the filter 11. The base 15 of the body 10 of the flame arrester device has the shape of a frame on which is attached inside the hollow volume V (preferably parallel to said frame), the periphery 20 of the explosion panel 2.The frame of the base 15 of the flame arrester and the periphery 20 of the explosion panel are provided with holes for fixing preferably by bolting around the hole of the enclosure to be protected. The body 10 of the flame arrester device, the filter 11 and the grid 12 are not further described because they are known per se.

[0021] Due to the configuration according to the invention of the explosion panel 2 with regard to its weakening zone 3, the hollow volume V of the flame arrester device 1 of the invention can be reduced in depth (or in height) between its base 15 of plane P' and the plane P of the opposite face of the box 13 and allows, for the shape of the flame arrester device of figures 1 to 3, to provide a grid and filter assembly, which is of flat shape. Several embodiments of the explosion panel 2 (figures 4, 9 and 13) are described below in order to provide a volume V reduced in dimension between the planes P and P'. In a manner common to all embodiments, the explosion panel 2 comprises a peripheral fixing frame 20, a metal sheet 21 called a rupture sheet which is integral with the frame 20 and the weakening zone 3 which is capable of tearing in the event of abnormal overpressure in the enclosure for which the flame arrester device is intended.The flame arrester device 1 also comprises sealing means 4 (notably illustrated in figures 7 and 10) which are systematically arranged opposite the weakened zone 3 and at the level of the bolting fixing surface in order to ensure sealing with respect to the interior of the enclosure for which the flame arrester device 1 is intended.

[0022] Concerning the sealing means 4 at the surface by bolting, they are rather arranged between the peripheral frame 20 of the explosion panel 2 and the base 15 of the flame arrester device. The peripheral frame 20 of the explosion panel 2 is provided with bores 20' ([Fig.4]) for its fixing by bolting to the peripheral base 15 of the box 13 of the flame arrester device and to the enclosure for which said flame arrester device is intended.

[0023] The rupture sheet 21 has a thickness of between 0.5 and 1.2 mm, for example of the order of 0.8 millimeters. The weakening zone 3 consists for example of discontinuous slots in the thickness of the sheet 21, generally made by laser, and connected by frangible solid parts.

[0024] The weakening zone 3 is arranged (or follows a path on the sheet 21) so that the sheet 21 is divided into at least two parts, here into two parts 3A and 3B of identical surfaces. The two parts 3A and 3B are intended to provide two leaves when the weakening zone 3 breaks and therefore when the panel 2 opens. Thus, the breaking sheet 21, by opening in a direction perpendicular to its general plane, reaches a length dimension which is reduced, in particular to half the sheet, compared to the dimension that the sheet would have if it opened in a single part from one of its edges as is usual in the state of the art.

[0025] The embodiments presented below present different examples of arrangement of the weakening zone 3.

[0026] In Figures 1 to 7, the explosion panel 2 is rectangular, generating a rectangular-shaped sheet 21. The weakening zone 3 draws, according to a top view ([Fig.4]), a general H-shape. The weakening zone 3 thus corresponds, on the one hand, to the longitudinal median line 30 of the largest dimension of the sheet (the length of the sheet) and, on the other hand, starting from the ends of the median line 30 and perpendicular to it in the two opposite directions, two pairs 31 and 32 of lines opposite each other. The lines 31 and 32 correspond to peripheral lines (close to the fixing frame 20) which are perpendicular to the median line 30 and which extend along the two opposite (small) sides of the width of the sheet. According to this arrangement of the weakening zone 3 in two parts 3A and 3B, the sheet 21 is capable of breaking as illustrated in [Fig.5], in two leaves 3A and 3B from the longitudinal center line 30 and in two opposite directions (pivoting according to the arrows F of [Fig.3] towards the peripheral wall 14 of the box). The large sides 33 and 34 of the rectangular sheet 21 being solid ([Fig.5]), they play the role of two hinges for the leaves 3A and 3B.

[0027] To ensure the sealing of the explosion panel 2 at the level of the weakening zone 3, the panel 2 comprises the sealing means 4. The sealing means 4 comprise a sealing joint 40 (figures 7 and 8) opposite the median line 30 and a sealing joint 41 opposite the peripheral lines 31 and 32.

[0028] The seal 40 is advantageously secured to a retaining plate 5 (figures 6 to 8) which is preferably fixed by welding on the internal face of the sheet 21 (inside the box 13) and straddling the center line 30 of said sheet 21. The seal 40 is sandwiched between the retaining plate 5 and the sheet 21. The holding plate 5 is limited in width relative to the rest of the sheet 21 to simply serve to hold the joint 40. Here, the plate 5 has, in top view, a profile which is in “crenellations” on each of its longitudinal edges but which could be straight. The flat crenellated profile makes it possible to lighten the plate and, above all, to serve as reference points for welding (at the level of each “merlon”). The plate 5 is thin in thickness, for example of the order of 0.5 mm. Finally, the plate 5 also has a weakening line 50 opposite the central weakening line 30 of the sheet 21 (with the joint 40 at the interface).

[0029] The sealing gasket 41 is a gasket which runs all the way around the frame 20 of the explosion panel 2 and which straddles the frame 20 and the sheet 21, covering the peripheral lines 31 and 32. The sealing gasket 41 is secured to the so-called external face of the explosion panel 2, a face which is located opposite the interior of the box 13 and which is intended to come into contact with the periphery of the base 15 of the flame arrester device at the level of the entire bolting fixing zone.

[0030] Furthermore, the plate 5 may comprise, preferably here at the distal ends in line with the peripheral lines 31 and 32, tabs 51 which project towards the inside of the box 13; the tabs 51 serve as targets for detectors (not shown) in order to detect or control the activation of the explosion panel 2.

[0031] The variant of [Fig.9] illustrates an explosion panel 2 also rectangular with its rectangular sheet 21 but with another arrangement for the weakening zone 3. The weakening zone 3 draws, according to a top view, a general shape of two U or C facing each other (the openings of the U being facing each other) from the periphery, providing two parts 3A and 3B. More particularly, the weakening zone 3 extends at the periphery of the sheet 21 for each of the U's, along a main branch 35 parallel to the two large opposite sides 33 and 34 and along two parallel lateral branches 36 and 36' which extend perpendicularly from the ends of the main branch 35. The pair of lateral branches 36 and 36' of a U is directed towards the other pair of branches of the other U without joining so as to leave between the two U's a solid median zone 37 intended to form a zone with a hinge function for the two parts 3A and 3B.According to this arrangement of the weakening zone 3, the sheet 21 is able to open as illustrated in [Fig. 11] and in [Fig. 12] (pivoting according to the arrows F), in two leaves 3A and 3B from the periphery of the long sides 33 and 34 and towards the center of the rectangle. The two leaves 3A and 3B open back to back. Preferably, so that the two parts 3A and 3B of the sheet do not collide, the flame arrester device 1 comprises a stop surface 6 which extends in the middle zone 37 of the sheet and perpendicular to the general plane of the explosion panel 2. The stop surface 6 is for example a flange fixed on the one hand, to the sheet 21 in its longitudinal middle zone, and on the other hand, to the . body of the box 13 on its face opposite that coupled to the panel. Alternatively, the stop surface 6 may comprise at least two uprights also fixed to the sheet 21 in its middle part and opposite the body of the box 13; the stop surface 6 may optionally comprise a connecting part between the two uprights.

[0032] In the example of [Fig. 9] to ensure the sealing of the explosion panel 2 at the right of the weakening zone 3, the sealing means 4 comprise a sealing gasket 41 ([Fig. 10]) which is similar to that of the example panel of [Fig. 7]. The gasket 41 is arranged under the panel 2, that is to say on the external face of the panel, opposite the interior of the volume V of the flame arrester device to come into contact against the peripheral base 15 of said flame arrester device over the entire perimeter of the zone by bolting. The gasket 41, being arranged on the external face, is fixed astride the peripheral frame 20 and the sheet 21, as illustrated schematically.

[0033] In the example of [Fig. 12], to ensure the sealing of the explosion panel 2 at the right of the weakening zone 3, the sealing means 4 correspond to the sealing gasket 41 by being arranged under the panel 2, that is to say on the so-called external face which is the opposite face of the interior of the volume V of the flame arrester device and the face coming into contact with the base 15 of the flame arrester device. The gasket 41, by being arranged on the external face, is fixed astride the peripheral frame 20 and the sheet 21 in the same way as for the rectangular panel of [Fig. 10].

[0034] For a square-shaped explosion panel, the weakening zone 3 could be of the same design as that of the examples in Figures 4 and 9, the center line 30 along the length of the rectangle then corresponding to one of the center lines of the square shape.

[0035] In the example explosion panel of [Fig. 13], the explosion panel2 is circular in shape, generating a circular-shaped sheet 21. The circular shape of the explosion panel 2 is linked to the cylindrical shape of the flame arrester device 1 ([Fig. 15]). The weakening zone 3 draws, according to a top view, a general shape according to two facing semicircles which do not touch. More particularly, the weakening zone 3 extends at the periphery of the sheet 21 along two circular arcs 38A and 38B with an angle close to 180° without joining, leaving a solid central zone 39. According to this arrangement of the weakening zone 3, the sheet 21 is divided into two parts 3A and 3B which are capable of being deployed, as illustrated in [Fig. 14] and in [Fig. 15], in two leaves from the periphery of the two semicircles and in the direction of the center (according to the arrows F illustrated in [Fig. 15]), the solid zone 39 which extends along the diameter corresponding to a zone with a pivoting hinge function of the leaves 3A and 3B.The two parts 3A and 3B open back to back. Preferably, so that the two leaves 3A and 3B of the sheet do not . do not strike, the flame arrester device 1 comprises a stop surface 6 which extends in the middle part of the sheet and perpendicular to the general plane of the explosion panel. The stop surface 6 is for example a flange fixed on the one hand, to the sheet 21 in its middle part according to the diameter, and on the other hand, to the body of the box 13 on the face opposite that carrying the panel. Alternatively, the stop surface 6 can be uprights also fixed to the sheet 21 in its middle part and opposite the body of the box 13; the stop surface 6 can optionally comprise a connecting part between the two uprights.

[0036] In the example of [Fig. 15], the explosion panel 2 and therefore its frame 20 is arranged under the frame 15 of the flame arrester device 1; to ensure the sealing of the explosion panel 2 at the level of the weakening zone 3, the panel 2 comprises sealing means not illustrated such as a seal arranged on the panel, on the internal face of the panel covering the weakening zone 3 and the peripheral frame 20, and on which the base 15 of the flame arrester device rests.

Claims

Claims

1. Flame arrester device (1) comprising a hollow box (13), a filter (11) and a depressurization device which comprises at least one explosion panel (2) comprising a sheet (21) called a rupture panel provided with a weakening zone (3), the box (13) having inside it two opposite faces, one of which carries the explosion panel (2), the weakening zone (3) is arranged so as to draw in the sheet at least two parts (3A, 3B) which are intended to constitute respectively at least two leaves (3A, 3B) in the event of rupture of the weakening zone of the sheet, the weakening zone comprising a longitudinal median line (30) and the leaves opening face to face, characterized in that the explosion panel (2) comprises sealing means opposite the weakening zone, the sealing means comprising, on the one hand,a seal (40) which is integral with a plate (5) fixed astride the center line of the sheet or which is integral with a plate fixed only on one of the two parts of the sheet, part intended to constitute one of the leaves, the seal being sandwiched between the sheet and the plate, and the plate having a weakening line opposite the weakening line of the sheet, and on the other hand, a seal (41) which is arranged astride peripheral lines (31, 32) on the face of the sheet opposite that facing the inside of the box.,

2. Flame-retardant device according to claim 1, characterized in that the weakening zone (3) is arranged so as to form two parts (3A, 3B) of identical shapes which are intended to constitute two leaves of identical surface area.

3. Flame arrester device according to claim 1 or 2, characterized in that the distance separating the sheet (21) from the opposite face of the box has a dimension which corresponds to the correct passage of the leaves (3A, 3B).

4. Flame arrester device according to any one of the preceding claims, characterized in that the plate (5) is limited in width relative to the rest of the sheet (21) to simply serve to maintain the seal (40) covering the center line.

5. Flame arrester device according to any one of the preceding claims, characterized in that the weakening zone (3) extends according to a general H shape in top view, in particular according to a median line (30) of the panel, which is the line of greatest direction when the panel is rectangular in shape, and according to two pairs of peripheral lines (31, 32) which start perpendicularly in two opposite directions from the median line (30), so as to draw said at least two parts (3A, 3B) which are intended to constitute leaves respectively.

6. Flame arrester device according to any one of the preceding claims, characterized in that the plate (5) is fixed by welding on the so-called internal face of the sheet (21) and straddling the median line (30) of said sheet (21).

7. Flame arrester device according to any one of the preceding claims, characterized in that the plate (5) has, in top view, a profile which is in “crenellations” on each of its longitudinal edges.

8. A flame arrester device according to any one of the preceding claims, characterized in that the plate (5) comprises tabs (51) which project towards the inside of the box (13), the tabs (51) serving as targets for detectors in order to detect or control the activation of the explosion panel (2).

9. Flame arrester device according to any one of the preceding claims, characterized in that the plate (5) is of the order of 0.5 mm thick.

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