DE19957836B4 - Method and device for damping the pressure surge on flame arresters during detonations - Google Patents

Abstract

Process for damping the pressure surge on flame arresters, in particular tape fuses, in the event of detonations of a combustible gas / air and / or steam / air mixture in plant, container and piping systems, in which the starting detonation front is divided into a plurality of partial reaction fronts which Immediately afterwards deflection-free and almost laminar are fed to the band lock for extinguishing any flames, characterized in that the starting detonation front is directed onto a band fuse-like pre-filter with gap-like channels for dividing the detonation front, the gap widths of the channels being well above the standard gap width of the respective gas / air - And / or steam / air mixture and the gap length of the channels are set significantly above those of the tape fuse depending on the type, temperature and pressure of the gas / air or steam / air mixture.

Description

The invention relates to a method for steaming of the pressure surge on flame arresters, especially band fuses, in the event of detonations a flammable gas / air and / or steam / air mixture in plant, Container- and piping systems in which the starting detonation front is divided into a large number of partial reaction fronts, the immediate subsequently deflection-free and almost laminar of the tape backup to delete any Flames fed become.

The invention further relates to a Steaming device of the pressure surge on flame arresters, especially tape fuses, in the event of detonations flammable gas / air and / or steam / air mixture in plant, container and piping systems, with housing parts lying in the direction of the pipe axis in passage and corner design and one perpendicular to this axis arranged, between the housing parts clamped dry flame arrester from at least one band fuse with or without one towards the ignition source directed bumper.

Detonation devices are elements of constructive explosion protection in containers, systems and especially in connecting pipelines, in which flammable gas / air mixtures and / or steam / air mixtures stored or transported, the spread (reproduction) detonatively prevent explosions. Under appropriate process conditions and configuration of the systems, in particular the length of the connecting pipelines, detonations develop from deflagration out with propagation speeds up to 3000 m / s and pressure peaks up to 100 bar.

The well known used in detonation devices Flame arrestors, their effect on the principle of flame extinguishing Column based therefore withstand high mechanical and thermal loads.

To reduce these burdens, the state of the art sets on the side facing the ignition source Construction elements that create the shock wave of the detonation front weakens before hitting the flame arrester.

So is from the DE 28 47 500 a detonation brake is known, which consists essentially of a semi-cylindrical reflection wall, which absorbs a large part of the energy of the pressure shock waves and reduces the pressure surge. The prior art proposes similar solutions in the DE 1 075 501 and DE 1 192 980 in front.

From the EP 0 375 455 A1 a pot-shaped bumper is also known, which is arranged in the direction of the ignition source in front of the tape fuses and is intended to weaken the energy of a possible detonation.

These known solutions reduce the pressure surge on the Tape backup, lead however to increase of turbulence in the flame front, so that especially in the case of unfavorable ones Conditions, for example in the case of an unstable detonation, undesirable pressure peaks arise. Furthermore, there is a risk that behind the Built-in new detonation fronts by reflection on the housing wall build up, the pressure peaks of which act directly on the belt securing device and cause flame arrest.

The tries these disadvantages DE 44 38 797 C1 to be remedied in that flow straighteners are arranged between the bumper and the flame arrester at the shortest distance parallel to the flame arrester, which have a free flow area which corresponds to 0.5 to 2.0 times the nominal cross-sectional area of the pipeline.

Another known solution of the prior art ( DE 195 36 292 C2 ) plans to divide the starting detonation front and bring it together again in an expansion room. The detonation front is divided into a main front and a side front, the main front being led into the expansion space with a longer running time, so that when the main front enters the expansion space these combustion gases contain the side front. The wall arrangement for dividing and deflecting the detonation front forms a first line path for the main front and a second line path for the side front. The pipeline routes are dimensioned so that the main front enters the expansion area with a delay compared to the secondary front.

The DE 198 18 572 C1 discloses a method for rendering a detonation front conducted in a pipeline harmless with the aid of a flame arrester, in which the detonation front is guided so close to the flame arrester which has a larger diameter than the pipeline that the detonation front strikes only a partial area of the flame arrestor and that the detonation front is so before the flame arrester is expanded, a deflagration occurs, which strikes the outer cross section of the flame arrester.

All of these known solutions result hers in the flow path existing fixtures or through additional lines or reflection walls to Redirecting and dividing the detonation front to high pressure losses and problems in reproducibility in operating behavior of the fittings. additionally the internals require longer lengths, which means the known fittings are material-intensive and also expensive become.

This is the state of the art The task is based on improving a method and a device of the type mentioned at the outset in such a way that the band safety device is acted on with or without prior deflection of the detonation front and largely without reflection, with a simultaneous shortening of the overall length.

This task is accomplished through a process of the type mentioned at the outset in that the approaching detonation front on a band fuse-like pre-filter with gap-like Channels to Splitting the detonation front is steered, the gap widths of the channels well above the standard gap width of the respective gas / air and / or steam / air mixture and the gap length of the channels well above depending on the tape backup the type, temperature and pressure of the gas / air or steam / air mixture can be set.

There are gap widths of the channels of at least 10 to 200, preferably 80%, greater than the gap width of the band protection and gap lengths of the channels of at least 1 to 20 times, preferably 6.3 times the gap length of the Tape backup, proven to be beneficial.

Another preferred embodiment of the inventive method provides that the partial reaction fronts of the detonation front in Size and direction evenly trained are.

In a further advantageous embodiment of the method according to the invention the detonation front is divided into partial reaction fronts in front of or near the tape backup, so the tape backup is almost laminar over the entire installation area largely applied without transverse shocks becomes.

The task continues with one Device of the type mentioned solved in that on the of the ignition source facing side of the housing part near the tape backup parallel to this a tape backup type Pre-filter is arranged, the gap width significantly above that Standard gap width of the respective gas / air and / or steam / air mixture and clearly above the gap length the tape backup is located.

According to another preferred feature of device according to the invention the gap width of the prefilter is at least 10 to 200, preferably 80%, over the gap width of the tape fuse.

Another preferred feature the device according to the invention stipulates that the gap length of the pre-filter the gap length the tape backup exceeds at least 1 to 20 times, preferably 6.3 times.

Tape backup and prefilter are expediently by a star-shaped Spacer element spaced, being in the space between tape securing and pre-filter a temperature sensor is arranged protruding.

In a further preferred embodiment the device according to the invention the pre-filter is placed directly on the belt fuse. Thereby Is it possible, the overall length to shorten the valve extremely.

In a further embodiment of the invention is the prefilter of the bumper arranged upstream and / or downstream or in or on the bumper.

The solution according to the invention is characterized by this from that the detonation front hitting the prefilter through the long narrow channels of the pre-filter into a variety of partial reaction fronts under considerable damping of the mechanical pressure surge be isolated. about the boundary layers of the channel walls heat energy is withdrawn, which leads to a weakening the flame front leads. When flowing through of these channels of the pre-filter, the turbulence of the partial reaction fronts becomes significant reduced. Transversal shocks will be largely suppressed so that the main driver of the detonation front is removed is.

All of these features result in that when the partial reaction fronts emerge from the prefilter, a there is almost laminar spread.

With the present invention it possible those resulting from the detonation Pressure surges without A bumper or reflection walls with low pressure loss while reducing the overall length of the Dismantle fittings.

Further details emerge from the following description with reference to the accompanying drawings.

The invention is intended to: an embodiment are explained in more detail.

Show it:

1 a basic arrangement of flame arrester and prefilter without a bumper as a passage design with one-sided exposure,

2 a variant according to 1 , but with bilateral loading,

3 another variant according to 1 in corner design with one-sided loading,

4a - 4c Arrangements of band fuses and pre-filters with bumpers as a passage design with one-sided loading and

5 a further embodiment of the invention, in which the pre-filter is placed directly on the belt fuse.

In a pipeline 1 , which leads to a container, not shown, with an explosive gas / air mixture, is the device according to the invention in the axial direction 2 by means of a flange 3 attached. The device 2 consists of a housing part 4 and a housing part 5 , That from a fourfold tape backup 6 , Spacers 8th and 10 existing flame arrester 7 is after 1 perpendicular to the pipe axis or housing axis between the two housing parts 4 and 5 clamped. The tape backup 6 is based on the in on the side of the housing 4 adjacent star-shaped spacer 8th from.

In the example selected here, the tape fuses have 6 a gap width of 0.5 mm and a gap length of 10 mm. In the housing part facing the ignition source 5 there is a pre-filter perpendicular to the pipe axis 9 one that is on the star-shaped support element 10 the flame arrester 7 supported. The pre-filter 9 consists of a band-drawing-like element with a gap width of 0.9 mm and a gap length of 63 mm. The pre-filter 9 is at the shortest distance from the actual flame arrester 7 away.

When an ethylene / air mixture detonates, for example, the detonation front moves onto the prefilter 9 and penetrates into the pre-filter 9 separate channels formed by the gap width of the individual layers of the tape fuse. The detonation front is subdivided into parallel partial partial front fronts which move through the channels of the tape fuse. Thermal energy is extracted from the individual fronts as the channels pass through and the turbulence is considerably reduced.

In the example chosen here, the gap width of the pre-filter was 9 to over 80% of the gap width of the tape backup 6 the flame arrester 7 set. It is therefore significantly above the standard gap width of the ethylene / air mixture. The selected gap length is 6.3 times the gap length of the actual tape backup 6 ,

In the 2 and 3 corresponding embodiment variants of the invention are shown.

4 shows the combination of bumper 11 and pre-filter 9 , the pre-filter depending on the requirements in front, behind, on or in the bumper 11 be provided. can without departing from the invention.

Another variant of an embodiment of the device according to the invention is the 5 In this variant is the prefilter 9 direct part of the tape backup 6 , The through the pre-filter 9 isolated partial reaction fronts of the detonation front meet directly with the tape fuse 6 on.

1

pipeline

2

contraption

3

Flange on 1

4

housing part

5

housing part

 6

tape backup

7

flame arrester

8th

spacer

9

prefilter

10

spacer

11

A bumper

Claims (11)

Process for damping the pressure surge on flame arresters, in particular tape fuses, in the event of detonations of a combustible gas / air and / or steam / air mixture in plant, container and piping systems, in which the starting detonation front is divided into a plurality of partial reaction fronts which Immediately afterwards deflection-free and almost laminar are fed to the band lock for extinguishing any flames, characterized in that the starting detonation front is directed onto a band fuse-like pre-filter with gap-like channels for dividing the detonation front, the gap widths of the channels being well above the standard gap width of the respective gas / air - And / or steam / air mixture and the gap length of the channels are set significantly above those of the tape fuse depending on the type, temperature and pressure of the gas / air or steam / air mixture. A method according to claim 1, characterized in that the gap width of the channels to at least 10 to 200%, preferably 80%, larger than the gap width of the Tape securing and the gap length of the channels at least 1 to 20 times, preferably 6.3 times, the gap length the tape backup is set. A method according to claim 1 or 2, characterized in that that the partial reaction fronts of the detonation front in size and direction evenly trained are. A method according to claim 1 to 3, characterized in that the division of the detonation front into partial reaction fronts in front of or close to or directly on the tape backup, so that tape backup over their entire installation area largely applied without transverse shocks becomes. Device for damping the pressure surge on flame arresters, in particular tape fuses, in the event of detonations of a combustible gas / air and / or steam / air mixture in plant, container and piping systems, with housing parts in the pipe axis direction in passage or corner design and one vertically therein Dry flame arrester arranged to this axis from at least one band fuse with or without a bumper directed towards the ignition source, characterized in that on the side of the housing part ( 3 ) near the tape backup ( 6 ) parallel to this a tape fuse-like pre-filter ( 9 ) is arranged, the gap width clearly above the standard gap width of the respective gas / air and / or steam / air mixture and clearly over the gap length of the actual tape securing ( 6 ) lies. Apparatus according to claim 5, characterized in that the gap width of the pre-filter ( 9 ) is at least 10 to 200, preferably 80%, larger than the gap width of the tape fuse ( 6 ). Apparatus according to claim 5, characterized in that the gap length of the pre-filter ( 9 ) the gap length of the band lock ( 6 ) at least 1 to 20 times, preferably 6.3 times. Apparatus according to claim 5 to 7, characterized in that the pre-filter ( 9 ) directly on the tape backup ( 6 ) is placed on top. Apparatus according to claim 5 to 8, characterized in that tape securing ( 6 ) and pre-filter ( 9 ) with a star-shaped spacer ( 10 ) are spaced, whereby in the space between tape securing ( 6 ) and pre-filter ( 9 ) at least one temperature sensor is arranged protruding. Apparatus according to claim 5 to 9, characterized in that the pre-filter ( 8th ) the bumper ( 11 ) is arranged upstream and / or downstream. Apparatus according to claim 5 to 10, characterized in that the pre-filter ( 9 ) in or on the bumper ( 11 ) is arranged.