EP0765675B1 - Method and apparatus for damping a detonation in a container or a pipework system - Google Patents

Abstract

The detonation front is divided into a main and smaller subsidiary front. The main front is introduced into the expansion chamber (17) with a longer operation time so that the expansion chamber contains combustion gases of the subsidiary front. The operation time of the main front in relation to the subsidiary front is such that the subsidiary front is already completely disintegrated in the expansion chamber when the main front enters the expansion chamber. After the disintegration of the detonation, the gas for extinguishing any residual flames is conducted through a flame-extinguishing barrier (7) with gaps in.

Description

The invention relates to a method for weakening a detonation in a container or piping system in which a starting detonation front divided and in an expansion room is merged again.

The invention further relates to a device for weakening a detonation in a container or piping system with a wall arrangement lying in the propagation path of the detonation front to divide and redirect the detonation front and with an expansion room in which the split detonation front again is merged.

The spread of an explosion of an ignitable gas mixture in a container or piping system can be used as a detonation or done as deflagration. During the detonation the overlap Flame front and the one formed by the blast of the explosion Shock front, while during deflagration the shock waves of the flame front hurry ahead. The flame propagation rate of Deflagrations are around 100 m / sec. and the combustion pressures in the direction of impact at up to 10 bar (at an outlet pressure the mixtures of 1 bar), while in the case of detonations flame propagation speeds of several 1,000 m / sec. and pressures can occur in the direction of impact of up to 100 bar.

It is known to suffer from the destructive effects of detonations Avoid weakening or ending the detonation and preferably the flames of the flame front of the detonation to To bring it out. So-called "detonation brakes" are often or "detonation bumper" combined with a flame arrester, which has a large number of narrow and long gaps, in to whom the flame is cooled so much that it goes out is coming.

A detonation device consisting of a detonation brake and a flame arrester is known from DE-PS 1 192 980. The propagating detonation front through a pipeline in the known device by the convex outside of a divided circular cylindrical wall and gets into a Expansion room with an enlarged one compared to the pipeline Volume. The split detonation front can only take several Redirections against the flame arrester run in one Outlet connector is attached, which is 90 ° relative to the pipeline is angled, in which the detonation originally spreads Has. The multiple redirections are required that a second semicircular cylindrical wall with a smaller one Diameter is provided, the mutually pointing fine wall pieces are arranged overlapping one another and thereby one Form a kind of labyrinth. In these known devices the converging partial detonation fronts a post-detonation trigger, especially when unfavorable mixture conditions available. It is therefore necessary to close the flame arrester in this way dimension that in this case, too, it is a safe flame-extinguishing Has effect. The flame extinguishing column of the flame arrester must be sufficiently long and sufficiently narrow be, however, for normal operation when flowing through the operating medium a relatively high pressure loss must be accepted. Furthermore narrow and long passage gaps result in increased maintenance.

A similar device is known from DE-A 934 574 and DE-A 937 879. The The flame arrester is located in a 90 ° angle to the pipe Support. In a pot-like housing is flush with the pipeline a tapered nozzle is provided, which is a widening nozzle at a distance opposite. At the edge of the tank there is a curved return line is directed back to the pipeline. The main stream of incoming Gas flow flows through the tapered nozzle and produces it at the outlet Nozzle that is sucked away by the gases from the flame arrester should. The main flow through the opposite nozzle is through the Return line led back and impinges there on a bypass of the explosion pressure starting, which flows laterally into the return line before entering the nozzle. Due to the colliding currents, the explosion pressure is reduced. about a buffer space between the nozzles and the flame arrester can do this essentially Drain any gas that has come to a standstill through the flame arrester. The well-known The device is used to protect against explosions and is not for use with detonations starting at significantly higher energy and speed are suitable.

The invention is therefore based on the object of a method and a device specify by which the attenuation of a detonation in a container or Piping system can be improved.

This object is achieved according to the invention with a method of the type mentioned at the outset solved by dividing the detonation front into a main front and there is a much smaller secondary front and that the main front with a longer term is directed into the expansion space, so that when the Main front in the expansion space of these combustion gases contains the side front.

While the operation of the known detonation mitigation devices rested on the fact that the detonation front was as effective and is deflected frequently so as to reduce the rate of reproduction and To consume energy, the solution according to the invention is based on the fact that a preferred smaller part of the detonation front as a side front in the expansion space is directed and burns there, preferably in the form of a deflagration, so that the The main front essentially finds exhaust gases when entering the expansion space, which hinders the propagation of the detonation, making it regular disintegrates. This is ensured if the running time of the main front is relative to the secondary front is dimensioned so that the secondary front in the expansion space is already complete has decayed when the main front enters the expansion space.

The method according to the invention can be used in all container or pipe systems use to destroy or at least mitigate detonations. For Connection points in other systems or in the outdoor area is expedient combined with a conventional flame arrester, the improved effect of the detonation attenuation according to the invention causes the flame arrester to have less narrow and / or few long flames must have an extinguishing column so that the one caused by the flame arrester Pressure drop for normal operating conditions is reduced.

The method according to the invention is particularly effective when the secondary front in the part of the expansion space on the outlet side, that is, for example, until short in front of a flame arrester located there, before entering the expansion room can. This caused the opposite front to burn off and enter the main front into the expansion chamber leads to an even improved and yet safer detonation mitigation.

A device of the beginning which functions according to the method according to the invention mentioned type is characterized in that the first route for the main front and a second line for a secondary front of the detonation front forms, the total cross section of the first conduction path being substantially larger is dimensioned as the total cross-section of the second route and the route are that the main front compared to the secondary front is delayed in the expansion space entry. The overall cross section of the first conduction path is preferred at least four times the total cross-section of the second route.

To ensure that the detonation of the secondary front when entering the expansion chamber has gone into deflagration, the second route is in one preferred embodiment of at least one opening or at least one Line piece formed, the diameter of each below the critical diameter lies. The term "critical diameter" is based on the knowledge that below a certain diameter of a pipe section butt front and flame front can no longer advance together and are therefore separated. Explanations of the term "critical pipe diameter" can be found in the article by Lee, J.H.S. Dynamic Parameters of Gaseous Detonations, Ann.Rev.Fluid.Mech. 16 (1984), pages 311 to 336.

For the reasons mentioned above, the expansion space may be the most the wall arrangement in terms of flow through another end Flame arrester must be completed with flame-extinguishing columns.

For a compact structure of the device, the unnecessarily long delays avoids the main front, it is expedient if the second route the direct passage of the secondary front into the Expansion space allowed essentially without redirection. This is Particularly useful if the level has already been undershot the critical diameter for a flame front separation and shock front is taken care of, so that energy-consuming deflections are no longer required for the secondary front. Because the side front progresses essentially without delay, is that for the Main delay minimized required delay.

The second route can be in a simple embodiment by at least one in the direction of propagation of the detonation front lying opening of the wall arrangement can be formed. Alternatively for this purpose the second route is through at least one in the direction of propagation the line section lying on the detonation front educated. The line piece can expediently shortly before Flame arrest ends to counteract the burning of the Flame of the side front and the entry of the main front into the expansion space to ensure. With one in an angled Pipe piece arranged flame arrester, the line piece is expedient bent accordingly. The wall arrangement of the The device according to the invention can in a manner known per se have circular cylindrical wall section which the Detonation front divided into two main fronts and redirected and the at least one opening or a line piece for the passage has the secondary front.

In an alternative constructive embodiment, the Wall arrangement comprising a starting detonation front cup-shaped wall, in the bottom of which there is at least one opening or a line section as a second line path for the passage the secondary front is located, the first route on the Outside of the cylindrical sections of the cup-shaped wall runs.

Figur 1 -

einen Vertikalschnitt durch ein erstes, als Winkelstück ausgeführtes Ausführungsbeispiel der Erfindung,

Figur 2 -

einen Horizontalschnitt durch das erste Ausführungsbeispiel gemäß Figur 1,

Figur 3 -

einen Vertikalschnitt durch ein als Winkelstück ausgebildetes zweites Ausführungsbeispiel der Erfindung,

Figur 4 -

einen Horizontalschnitt durch das Ausführungsbeispiel gemäß Figur 3,

Figur 5 -

einen Vertikalschnitt durch ein drittes, als Winkelstück ausgeführtes Ausführungsbeispiel der Erfindung,

Figur 6 -

einen Horizontalschnitt durch das Ausführungsbeispiel gemäß Figur 5,

Figur 7 -

einen Vertikalschnitt durch ein linear ausgebildetes viertes Ausführungsbeispiel der Erfindung,

Figur 8 -

einen Vertikalschnitt durch ein linear ausgebildetes fünftes Ausführungsbeispiel der Erfindung,

Figur 9 -

einen Vertikalschnitt durch ein linear ausgeführtes sechstes Ausführungsbeispiel der Erfindung.

The invention will be explained in more detail below with reference to exemplary embodiments shown in the drawing. Show it:

Figure 1 -

3 shows a vertical section through a first exemplary embodiment of the invention designed as an angle piece,

Figure 2 -

2 shows a horizontal section through the first exemplary embodiment according to FIG. 1,

Figure 3 -

3 shows a vertical section through a second exemplary embodiment of the invention designed as an angle piece,

Figure 4 -

3 shows a horizontal section through the exemplary embodiment according to FIG. 3,

Figure 5 -

3 shows a vertical section through a third exemplary embodiment of the invention designed as an angle piece,

Figure 6 -

5 shows a horizontal section through the exemplary embodiment according to FIG. 5,

Figure 7 -

3 shows a vertical section through a linearly designed fourth exemplary embodiment of the invention,

Figure 8 -

3 shows a vertical section through a linearly embodied fifth exemplary embodiment of the invention,

Figure 9 -

a vertical section through a linearly executed sixth embodiment of the invention.

The device shown in Figures 1 and 2 has a as Angle-shaped housing 1 with a possible Detonation input flange 2 and one to do so output flange 3 angled by 90 °. Both Connection flanges 2,3 have walls 4,5, which face the inside of the housing 1 expand conically. In the expanded part the wall 5 of the outlet flange 3 is located a level 6, on which a conventional flame arrester 7 is placed is. The flame arrester 7 is made using an insert 8 of the housing 1 held in place The insert 8 has one essentially circular cylindrical wall 9 through a transition piece 10 is expanded into a lower free edge 11, which at the Flame arrester 7 is present.

The circular cylindrical wall 9 faces the one on the input side Flange 2 opposite side a slot-shaped opening 12 on and is on the opposite end flange 3 Page completed by a flat plate 13. The Insert 8 is screwed onto housing 1 as a whole Lid 14 kept sealed in place.

In the transition piece 10 is located in the vertical central plane the input-side connecting flange 2 an opening 15 with a Diameter less than 1/4 of the diameter of the input side Flange 2 is and a much smaller Part of the expanded cross section of the housing 1 before takes circular cylindrical wall 9.

The circular-cylindrical wall 9 also faces the inlet bottle 2 opposite area to the side of the opening 12 radial reinforcing ribs 16 which extend radially up to the height of the free edge 11 extend.

One through the inlet flange 2 of the housing 1 incoming detonation front arrives at the circular cylindrical one Wall 9 and is divided there. Because of the symmetry of the arrangement two main fronts are formed, around the circular cylindrical Wall 9 and the reinforcing ribs 16 run around and through the opening 12 into the interior space forming an expansion space 17 enter the circular cylindrical wall 9. The main fronts arrive thus via the described first route into the expansion space 17 and flame arrester 7.

A small part of the starting detonation front passes through the Opening 15 as a side front and goes directly into the expansion room 17, just before the flame arrester 7. The opening 15 thus forms a second line path on which a side front the detonation front reaches the expansion space 17.

Since the main fronts on the first route a longer way have to move into expansion space 17 as the side front, the side front reaches the expansion space in front of the main fronts 17. The secondary front disintegrates in expansion room 17 and burns as deflagration. If the main fronts in the Expansion space, this is - at least partially, preferably completely - filled with exhaust gases, so that the main fronts in the expansion space 17 no more or only flammable gases still find small amounts of it and insufficient energy can record for reproduction. The main fronts also fall apart therefore in the expansion space 17 before it goes to the flame arrester 7 reach.

The flame arrester 7 therefore only needs for the much less dangerous deflagrations can be designed have significantly less narrow and / or less long gaps. This creates a lower flow resistance and the Maintenance of flame arrester 7 made easier.

In the embodiment shown in Figures 3 and 4 the insert 8 'also forms the cover 14 of the longitudinal housing 1 the circular cylindrical wall 9 'has a diameter which corresponds to the outer diameter of the flame arrester 7. With the opening 12 on the opposite of the inlet flange Another circular cylindrical wall section is aligned on the side 18, which is concentric with the circular cylindrical wall 9 ', but is arranged with a smaller diameter. An opening 19 of the circular cylindrical wall section 18 points to the input side Connection flange 2, so that through the circular cylindrical wall 9 'partial main fronts formed by a through the opening 12, 19 formed labyrinth in the expansion space 17 'above the Arrest flame arrester 7.

Located in the axis of the input flange 2 in the circular cylindrical wall 9 'into the expansion space 17 'projecting pipe section 20, which has a diameter below of the critical pipe diameter a side front without deflection in the expansion space 17 'conducts, while the main front several times deflected and delayed get into the expansion space 17 '.

In the third embodiment shown in Figures 5 and 6 is compared to the second embodiment of the figures 3 and 4 the line piece 20 'angled down to the side front in a larger closer to the flame arrester 7 in the expansion room 17 'to initiate. In addition, the circular cylindrical Wall 9 '' formed as a semicircular section. The second circular cylindrical wall section 18 is provided with radial ribs 16 ' provided together with the ends of the circular wall section 9 '' form inlet openings 12 ', which laterally the wall arrangement and together with the opening 19 cause multiple deflections of the main fronts. In this embodiment the insert becomes 8 ″ - as in the first embodiment - A separate lid 14 attached.

In the fourth embodiment shown in Figure 7 points a housing 21 an input side lying in a common axis Connection flange 22 and connection flange on the output side 23 on. The inlet flange 22 opens with a cylindrical pipe section 24 into the interior of the housing 21 and is overlapped there by a cup-shaped wall 25. The cup-shaped wall 25 consists of a cylindrical Jacket wall 26 and one of the input-side connection flange 22 arched bottom 27. Between the tubular line piece 24 of the input-side connecting flange 22 and the cylindrical Wall 26 of the cup-shaped wall 25 on the one hand as between the cylindrical wall 26 and the housing 21 on the other hand, are annular gaps 28:29 formed a maze for one in the cup-shaped Wall 25 form an incoming detonation front, which from the cup-shaped wall 25 reflected over the inner annular gap 28 emerges and after deflection by 180 ° through the outer annular gap 29 enters an expansion chamber 30 through a flame arrester 7 is completed. The flame arrester 7 is between two than Mounting flanges 31 inserted parts of the housing 21 inserted and clamped by screwing the mounting flanges 31, the part of the space not containing the expansion space 30 Housing 21 only the taper on the outlet flange 23 contains.

In this embodiment, the side front is shown in the axis of the input-side connecting flange 22 lying opening 32 passed into the expansion space 30 without deflection.

In the embodiment shown in Figure 8, this is essentially with the embodiment shown in Figure 7 matches, there are several in the bottom 27 of the cup-shaped wall 25 Openings 32 symmetrical to the axis of the input flange 22 arranged, of which in the vertical cutting axis 3 opening 32 can be seen.

The exemplary embodiment shown in FIG. 9 corresponds to that in FIG Figure 7 illustrated embodiment with the difference that instead of the opening 32, a line piece 32 'is provided by that the side front in closer proximity to the flame arrester 7 in the Expansion space 30 is initiated.

All of the illustrated embodiments allow an effective one Weakening or termination of the detonation and therefore a slight one Loading of the flame arresters provided in these exemplary embodiments 7.

Claims (17)

1. Method of damping a detonation in a container system or pipeline system, in which method an approaching detonation front is divided up and guided together again in an expansion chamber (17, 17', 30), characterised in that the detonation front is divided up into a main front and a subsidiary front of substantially smaller formation and that the main front is conducted into the expansion chamber (17, 17', 30) with a longer travel time so that, when the main front enters the said expansion chamber (17, 17', 30), the latter contains combustion gases of the subsidiary front.
2. Method according to claim 1, characterised in that the travel time of the main front relative to the subsidiary front is calculated in such a way that the subsidiary front has already collapsed completely in the expansion chamber (17, 17', 30) when the main front enters the said expansion chamber (17, 17', 30).
3. Method according to claim 1 or 2, characterised in that, after the collapse of the detonation, gas for extinguishing any flame which still exists is conducted through a flame arrester (7) having flame-extinguishing slits.
4. Method according to one of claims 1 to 3, characterised in that the subsidiary front is conducted into the expansion chamber (17, 17', 30) at an opposite end relative to the main front.
5. Method according to claim 3 and 4, characterised in that the subsidiary front is conducted, before entering the expansion chamber (17, 17', 30), to a point just in front of the flame arrester (7).
6. Method according to one of claims 1 to 5, characterised in that the main front spreads out in the expansion chamber (17, 17', 30) in the opposite direction to the subsidiary front.
7. Device for damping a detonation in a container system or pipeline system, the said device having a wall arrangement, which lies in the propagation path of the detonation front, for dividing up and deflecting the said detonation front, and an expansion chamber (17, 17', 30) in which the divided-up detonation front is guided together again, characterised in that the wall arrangement (9, 16; 9', 18; 9'', 16', 18; 24, 25) forms a first conduction path for the main front and a second conduction path for a subsidiary front of the detonation front, the overall cross-section of the first conduction path being substantially greater than the overall cross-section of the second conduction path, and the conduction paths being dimensioned in such a way that the main front enters the expansion chamber (17, 17', 30) in a delayed manner in relation to the subsidiary front.
8. Device according to claim 7, characterised in that the overall cross-section of the second conduction path amounts to less than 1/4 of the overall cross-section of the first conduction path.
9. Device according to claim 7 or 8, characterised in that the second conduction path is formed from at least one opening (15, 32) or at least one conducting piece (20, 20', 32'), the diameter of which lies below the critical tube diameter in each case.
10. Device according to one of claims 7 to 9, characterised in that the expansion chamber (17, 17', 30) is closed off, at the other end, flow-wise, relative to the wall arrangement, by a flame arrester (7) with flame-extinguishing slits.
11. Device according to one of claims 7 to 11, characterised in that the second conduction path permits the direct passage of the subsidiary front into the expansion chamber (17, 17', 30), substantially without deflection.
12. Device according to one of claims 7 to 11, characterised in that the second conduction path is formed by at least one opening (15, 32) which lies in the direction of propagation of the detonation front.
13. Device according to one of claims 7 to 11, characterised in that the second conduction path is formed by at least one conducting piece (20, 20', 32') which lies in the direction of propagation of the detonation front.
14. Device according to claim 13, characterised in that the conducting piece (20, 20', 32') ends just in front of the flame arrester (7).
15. Device according to claim 13 or 14, characterised in that the conducting piece (20') is bent away towards the flame arrester which is disposed in an offset tubular piece.
16. Device according to one of claims 7 to 15, characterised in that the wall arrangement has a circular cylindrical wall (9, 9') which divides up and deflects the detonation front into two main fronts and has at least one opening (15) or conducting piece (20, 20') for the passage of the subsidiary front.
17. Device according to one of claims 7 to 15, characterised in that the wall arrangement has a cup-shaped wall (25) which encompasses the approaching detonation front and in the base (27) of which at least one opening (32) or conducting piece (32') is located as a second conduction path for the passage of the subsidiary front, and that the first conduction path (28, 29) extends along the outside of the cylindrical sections (26) of the cup-shaped wall (25).

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