US20010000837A1 - Method for rendering a detonation front harmless - Google Patents
Method for rendering a detonation front harmless Download PDFInfo
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- US20010000837A1 US20010000837A1 US09/756,915 US75691501A US2001000837A1 US 20010000837 A1 US20010000837 A1 US 20010000837A1 US 75691501 A US75691501 A US 75691501A US 2001000837 A1 US2001000837 A1 US 2001000837A1
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- Prior art keywords
- flame
- detonation
- arresting device
- pipe
- arresting
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17D—PIPE-LINE SYSTEMS; PIPE-LINES
- F17D1/00—Pipe-line systems
-
- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62C—FIRE-FIGHTING
- A62C4/00—Flame traps allowing passage of gas but not of flame or explosion wave
- A62C4/02—Flame traps allowing passage of gas but not of flame or explosion wave in gas-pipes
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D5/00—Safety arrangements
- F42D5/04—Rendering explosive charges harmless, e.g. destroying ammunition; Rendering detonation of explosive charges harmless
- F42D5/045—Detonation-wave absorbing or damping means
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S55/00—Gas separation
- Y10S55/20—Spark arrester
Definitions
- the present invention generally relates to a method and apparatus for rendering harmless a detonation front traveling in a pipeline and, more particularly, to a detonation safety device having a flame-arresting device that hinders the transmission of the detonation flame.
- the propagation of an explosion in a flammable gas mixture in a container and/or pipeline system can occur as detonation or as deflagration.
- detonation the flame front and the shock front created by the pressure wave of the explosion are superimposed such that flame propagation velocities may reach several thousand meters/second (m/s) and combustion pressures in the shock direction may reach upwards of 100 bars.
- the shock waves precede the flame front such that flame propagation velocities of deflagration are in the order of several hundred m/s and the combustion pressures in the shock direction are upwards of 10 bars (with an original pressure of the mixture of one bar).
- detonation brakes and/or “detonation shock catchers” (e.g., detonation absorbers), and farther includes a number of long and narrow slots. These long and narrow slots attempt to cool the flame until the flame becomes extinct.
- DE-PS 1192 980 (German patent) describes a detonation safety device consisting of a detonation brake and a flame arresting device.
- a detonation front propagating in a pipeline is split by a convex outer surface of a cylindrical wall and reaches an expansion space that has a volume comparatively greater than the pipeline.
- a second semicircular cylindrical wall of a smaller diameter than the cylindrical wall is provided such that two facing free wall parts of the cylindrical wall and the second semicircular cylindrical wall are overlapped, thereby forming a labyrinth of various turns.
- the split detonation front travels through the labyrinth until it reaches the flame-arresting device.
- the flame-arresting device is placed in an exit housing and angled at 90 degrees to the pipeline in which the detonation initially propagated.
- the split detonation fronts create a secondary detonation, especially under unfavorable mixture composition conditions. It is thus necessary to size the flame-arresting device in such a way that it performs the flame extinguishing function even in the secondary detonation case.
- the flame extinguishing slots of the arresting device must be adequately long and narrow so as to realize a relatively high pressure loss during normal pipeline operation.
- these long and narrow slots require high maintenance which can be costly and time consuming.
- DE 195 36 292 C2 teaches a split of the detonation front into a main front and a secondary front.
- the main front is conducted into the expansion space with a longer transit time so that upon entry into the expansion space the main front contains combustion gases of the secondary front.
- the splitting of the detonation into main and secondary fronts such that the main front needs a longer transit time to reach the expansion space also requires many turns which thus results in a minimum volume for the detonation safety device.
- a pre-installed shock buffer for at least the main front.
- shock buffer results in a relatively high fabrication cost especially when the detonation safety device is impacted by detonation fronts from both sides in which case the shock buffers must be installed on both sides of the flame-arresting device.
- a detonation safety device which renders harmless a detonation front traveling in a pipeline by the use of a flame-arresting device.
- the detonation safety device includes a housing built into a pipeline and/or container system having a specific diameter.
- the flame-arresting device is housed in the housing and hinders the detonation of the flame of the detonation front.
- the diameter of the flame-arresting device is significantly larger than the pipe diameter thus providing a desired low pressure drop. Since the diameter of the flame-arresting device is larger that the pipeline diameter, it is appropriate to convey the detonation front as several part-fronts to various parts of the flame arresting device. This arrangement also allows an even distribution of flowing gases over the comparatively large surface area of the arresting device during normal operations.
- a pipe stub extends from the pipe and into the housing.
- the outlet of the pipe stub is proximate to the flame-arresting device and creates an open space so that a detonation front traveling through the pipe stub impinges only on a portion of the flame-arresting device.
- the pipe stub is placed near the flame-arresting device such that the portion being impinged by the front is essentially equal to the pipeline diameter.
- the flame-extinguishing operating mode becomes more effective as the end of the pipe stub is placed closer to the flame-arresting device.
- the pipe stub may also include small (relative to the pipe diameter) connection openings between the pipe stub and the surrounding open space which causes pre-combustion of the detonation front in the expansion space.
- the pre-combusted gases avoid the tendency of a renewed detonation front in the expansion space, especially one caused by a reflection off the end wall of the expansion space furthest away from the arresting device. In this way, the length of the expansion space can be reduced.
- several pipe stubs are provided, where each of the pipe stubs have a smaller diameter than the diameter of the pipeline.
- the flame-arresting device has a total diameter of at least double the front impingement diameter so that low pressure drops are achieved during normal operations.
- a lower limit for the reduction of the gap between the end of the pipe stub and the flame-arresting device results from the need that, during normal operations, the total cross-section of the flame-arresting device be uniformly impinged at the usual, normally relatively low, flow velocities.
- the distance between the outlet of the pipe stub and the flame-arresting device is equal to or larger than one third of the pipe diameter and equal to or smaller than the pipe diameter.
- the detonation front is expanded before reaching the flame-arresting device in such a manner that a deflagration ensues and impinges on the outer cross-section of the flame-arresting device.
- a small portion of the detonation front is diverted to an expansion space for pre-burning so that pre-combusted gases can prevent a renewed formation of a detonation front in the expansion space.
- the detonation safety device of the present invention may be used without a shock buffer.
- FIG. 1 shows a flame-arresting device of the present invention
- FIG. 2 shows an expansion of a deflagration front initiated by secondary ignition by the detonation front
- FIG. 3 shows the flame-arresting device of the present invention under normal operating conditions
- FIG. 4 shows the flame-arresting device of the present invention with detonation fronts in both flow directions
- FIG. 5 shows the flame-arresting device of FIG. 1 with narrow slots
- FIG. 6 shows the flame-arresting device of FIG. 1 with openings on a pipe
- FIG. 7 shows the flame-arresting device of FIG. 1 with several pipe stubs of smaller diameter
- FIG. 8 shows the flame-arresting device of the present invention under normal operating conditions according to FIG. 7;
- FIG. 9 shows the flame-arresting device of FIG. 1 with two pipe stubs of smaller diameter
- FIG. 10 shows the flame-arresting device of the present invention under normal operating conditions according to FIG. 9.
- the detonation safety device includes a housing 2 which is inserted into a pipeline 1 .
- the housing 2 is flanged at both ends to the pipeline 1 thereby creating an inner space 3 of the housing 2 .
- the preferred shape of the housing 2 is cylindrical with a cross-section approximately equal to that of the flame-arresting device 5 .
- a pipe stub 4 extends from one end of the pipeline 1 into the inner space 3 , and extends to a flame-arresting device 5 mounted concentrically with the housing 2 .
- the flame-arresting device 5 is mounted between two halves 6 of the housing 2 and is secured by flange connections 7 .
- FIG. 1 further shows a detonation front 8 traveling through the pipe stub 4 and impinging upon a portion 9 of the flame arresting device 5 .
- the flame-arresting device 5 includes a diameter larger than the pipe and the detonation front such that the detonation front impinges only on a partial surface (e.g., portion 9 ) of the flame-arresting device 5 .
- the flame-arresting device 5 has a total diameter of at least double the front impingement diameter so that low pressure drops are achieved during normal operations.
- FIG. 2 shows an expansion of a deflagration front initiated by secondary ignition by the detonation front. Specifically, the detonation front impinges on the partial surface of the flame-arresting device 5 and then expands in front of the arresting device 5 so as to create a deflagration. The deflagration then impinges on the outer cross-section of the flame arresting device.
- FIG. 2 also shows that the pipe stub 4 includes a diameter D, and that the detonation front 8 impinges only on a portion 9 of the flame arresting device 5 (substantially equal to the diameter D of the pipeline 1 ).
- the diameter of the portion 9 of the flame arresting device 5 is approximately equal to the diameter D of the pipeline 1 .
- the detonation front which impinges upon only the portion 9 of the flame-arresting device 5 is subject to high flow resistance. This can be further reinforced by constructing the flame-arresting device 5 so that the impingement section (e.g., portion 9 ) is different from the peripheral sections of the flame-arresting device 5 .
- the shock wave of detonation front 8 encounters a relatively high flow resistance at the flame arresting device 5 due to the small diameter D.
- the detonation front 8 is partially reflected by the flame-arresting device 5 and is brought to extinction upon entering the portion 9 of the flame-arresting device 5 .
- the detonation front 8 also creates a secondary ignition in the expansion space 13 of the housing 6 located in the open area between the end of the pipe stub 4 and the flame-arresting device 5 .
- the expansion space 13 extends for a distance L 1 between the outlet of the pipe stub 4 to an end wall 10 of the housing 6 .
- the secondary ignition of FIG. 2 creates a deflagration in the expansion space 13 .
- This deflagration further impinges on the outer periphery portions of the flame-arresting device 5 which significantly lowers the flame propagation velocity and combustion pressure.
- the deflagration reflections from the walls of the expansion space 13 especially the end wall 10 surrounding the pipe stub 4 , could again initiate a detonation front.
- the detonation front is eliminated since the reflected deflagration front transformed into a detonation front encounters an already combusted gas mixture in front of the flame-arresting device 5 .
- the detonation front is rendered harmless.
- length L 1 is larger or equal to 0.5 D and smaller or equal to 2 D and more preferably equal to 0.6 D of the pipeline 1 ; however, other appropriate lengths may equally be used depending on the pressure drop across the arresting device 5 . It is noted that when pre-combustion occurs, the length L 1 may be reduced to one half of the pipeline diameter D.
- the detonation front is allowed to impinge only on a portion of the flame-arresting device 5 by conducting the detonation front very close to the flame-arresting device 5 by use of the pipe stub 4 .
- an expansion space is created on the inlet side of the flame-arresting device 5 which permits the detonation front to generate a deflagration, by secondary combustion. Since the flame-arresting device 5 is impinged by the detonation front only on a part of the flame-arresting device 5 surface it offers very high flow resistance.
- the free cross-section surface of the whole flame-arresting device 5 is preferably equal or greater than the pipe diameter D of the pipeline 1 .
- FIG. 3 further shows the open distance L 2 between the outlet end of the pipe stub 4 and the flame-arresting device 5 surface.
- the distance L 2 is chosen such that under normal operation conditions the flame-arresting device 5 is uniformly impinged by the flowing medium over the entire surface area of the flame-arresting device 5 . This takes place when L 2 is larger or equal to one third of diameter D and smaller or equal to than diameter D. However, it is further understood that the distance L 2 may obtain an optimal length depending on the pressure drop across the arresting device 5 .
- FIG. 4 shows the flame-arresting device 5 of the present invention with detonation fronts in both flow directions. Specifically, FIG. 4 shows the pipe stub 4 provided on both sides of flame arresting device 5 . Thus, the detonation safety device of FIG. 4 may be used for detonation fronts 8 traveling in either direction.
- FIG. 5 shows the flame-arresting device 5 with narrow slots 9 ′ about the center thereof and substantially directly in the path of the detonation front.
- the narrow slots 9 ′ of the flame-arresting device 5 provides a higher flow resistance to the detonation front 8 as compared to the slots of FIG. 1. It is advantageous for the slots 9 ′ in the impingement area to be narrower, while for reason of manufacturing the slot lengths of all of the slots are uniform over the whole flame-arresting device 5 cross-section.
- the pipe stub 4 is provided with small connection openings 12 that divert a portion of the entering detonation front 8 immediately after the beginning of housing 2 .
- the connection openings 12 transfer the detonation front 8 directly into the expansion space 13 which causes pre-combustion of the detonation front in the expansion space 13 .
- the burnt gases in the expansion space 13 hinder the generation of a secondary detonation by reflection of a deflagration off the end wail 10 of the housing 2 which results in a reduction in the length L 1 .
- FIG. 7 shows several pipe stubs 4 ′ each having a smaller diameters than diameter D (as shown in FIG. 1) of the pipeline 1 .
- the arrangement of the pipe stubs 4 ′ shown in FIG. 7 includes a central stub 4 ′ aligned with the pipeline 1 but having a slightly smaller diameter D than that of the pipeline 1 .
- Four additional pipe stubs 4 ′ are placed radially from the central stub 4 ′ at equal distances from each other.
- the flame-arresting device 5 is extremely large in relation to the diameter of the pipe stubs 4 ′ which allows the flame-arresting device 5 to obtain a very low pressure loss through during normal operation.
- the effective gap length L 2 is maintained and that a uniform distribution of the flowing medium on the flame-arresting device 5 during normal operation is obtain when the several pipe stubs 4 ′ are installed opposite the cross-section of the flame-arresting device 5 .
- the detonation front 8 traveling through the pipeline 1 is split into several partial detonation fronts 8 ′ that impinge on the corresponding portions 9 ′′ of the flame-arresting device 5 .
- the back end-wall 10 ′ limiting the length L 1 of the expansion space 13 , is formed by wall pieces that create a distribution space 14 in the flow direction in front of the flame-arresting device 5 .
- This expansion space 13 spreads from the diameter D of the pipeline 1 to the effective diameter of the flame-arresting device 5 , and further includes the pipe stubs 4 ′.
- FIG. 8 shows the normal operation of the flame-arresting device 5 such that normal part-streams 11 ′ pass through the stubs 4 ′ and are distributed uniformly on the cross-section surface of the arresting device 5 .
- FIG. 9 shows two pipe stubs 4 ′ which are placed equidistant from the center axis of the housing 2 and/or the flame-arresting device 5 . This arrangement also leads to partial detonation fronts 8 ′ of FIG. 9 and/or normal part-flows as shown in FIG. 10.
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Abstract
Description
- 1. 1. Field of the Invention
- 2. The present invention generally relates to a method and apparatus for rendering harmless a detonation front traveling in a pipeline and, more particularly, to a detonation safety device having a flame-arresting device that hinders the transmission of the detonation flame.
- 3. 2. Background Description
- 4. The propagation of an explosion in a flammable gas mixture in a container and/or pipeline system can occur as detonation or as deflagration. In the case of detonation, the flame front and the shock front created by the pressure wave of the explosion are superimposed such that flame propagation velocities may reach several thousand meters/second (m/s) and combustion pressures in the shock direction may reach upwards of 100 bars. In the case of deflagration, the shock waves precede the flame front such that flame propagation velocities of deflagration are in the order of several hundred m/s and the combustion pressures in the shock direction are upwards of 10 bars (with an original pressure of the mixture of one bar).
- 5. Several methods are known to avoid the destructive effects of detonations. These methods attempt to weaken and/or end the detonation, preferably by transforming the detonation into a deflagration prior to arrival at a flame-arresting device. In many instances, the flame-arresting device is combined with “detonation brakes” and/or “detonation shock catchers” (e.g., detonation absorbers), and farther includes a number of long and narrow slots. These long and narrow slots attempt to cool the flame until the flame becomes extinct.
- 6. By way of example, DE-PS 1192 980 (German patent) describes a detonation safety device consisting of a detonation brake and a flame arresting device. In this device, a detonation front propagating in a pipeline is split by a convex outer surface of a cylindrical wall and reaches an expansion space that has a volume comparatively greater than the pipeline. A second semicircular cylindrical wall of a smaller diameter than the cylindrical wall is provided such that two facing free wall parts of the cylindrical wall and the second semicircular cylindrical wall are overlapped, thereby forming a labyrinth of various turns. In order to extinguish the detonation, the split detonation front travels through the labyrinth until it reaches the flame-arresting device. The flame-arresting device is placed in an exit housing and angled at 90 degrees to the pipeline in which the detonation initially propagated.
- 7. However, in these known devices as described with reference to DE-PS 1192 980, the split detonation fronts create a secondary detonation, especially under unfavorable mixture composition conditions. It is thus necessary to size the flame-arresting device in such a way that it performs the flame extinguishing function even in the secondary detonation case. In order to accomplish the flame extinguishing function, the flame extinguishing slots of the arresting device must be adequately long and narrow so as to realize a relatively high pressure loss during normal pipeline operation. However, these long and narrow slots require high maintenance which can be costly and time consuming.
- 8. By way of further example, DE 195 36 292 C2 teaches a split of the detonation front into a main front and a secondary front. In the case of DE 195 36 292 C2, the main front is conducted into the expansion space with a longer transit time so that upon entry into the expansion space the main front contains combustion gases of the secondary front. It is noted, however, that the splitting of the detonation into main and secondary fronts such that the main front needs a longer transit time to reach the expansion space also requires many turns which thus results in a minimum volume for the detonation safety device. Thus, there is a need to use a pre-installed shock buffer for at least the main front. It is noted, however, that the use of the shock buffer results in a relatively high fabrication cost especially when the detonation safety device is impacted by detonation fronts from both sides in which case the shock buffers must be installed on both sides of the flame-arresting device.
- 9. In principle, it would be possible to use a flame-arresting device without a shock buffer. However, the slots of the arresting device must be quite long and narrow in order to achieve adequate safety, resulting in high pressure losses across the arresting device. If flame arresting devices with low pressure drop are used, the flame front entering the arresting device can push lighter non-combusted mixtures through the arresting device which would thus result in higher stream velocities and the creation of turbulence in the flame extinguishing slots in the flame front travel direction. The higher stream velocities would thus increase the combustion velocity and reduce the extinction capability and the flame arresting safety of the device. It is further known that if the arresting devices with high damming capability created by long and narrow slots are used to provide high flame arresting safety, significant operational drawbacks of high pressure losses will result in the arresting devices.
- 10. It is therefore an object of the present invention to provide a detonation safety device which is built with simple and inexpensive components.
- 11. It is a further object of the present invention to provide a detonation safety device which does not have large pressure drops.
- 12. It is still a further object of the present invention to provide a detonation safety device which provides a high degree of flame arresting safety.
- 13. It is another object of the present invention to provide a detonation safety device which does not use a shock buffer.
- 14. According to the invention, there is provided a detonation safety device which renders harmless a detonation front traveling in a pipeline by the use of a flame-arresting device. The detonation safety device includes a housing built into a pipeline and/or container system having a specific diameter. The flame-arresting device is housed in the housing and hinders the detonation of the flame of the detonation front.
- 15. The diameter of the flame-arresting device is significantly larger than the pipe diameter thus providing a desired low pressure drop. Since the diameter of the flame-arresting device is larger that the pipeline diameter, it is appropriate to convey the detonation front as several part-fronts to various parts of the flame arresting device. This arrangement also allows an even distribution of flowing gases over the comparatively large surface area of the arresting device during normal operations.
- 16. A pipe stub extends from the pipe and into the housing. The outlet of the pipe stub is proximate to the flame-arresting device and creates an open space so that a detonation front traveling through the pipe stub impinges only on a portion of the flame-arresting device. The pipe stub is placed near the flame-arresting device such that the portion being impinged by the front is essentially equal to the pipeline diameter. The flame-extinguishing operating mode becomes more effective as the end of the pipe stub is placed closer to the flame-arresting device.
- 17. The pipe stub may also include small (relative to the pipe diameter) connection openings between the pipe stub and the surrounding open space which causes pre-combustion of the detonation front in the expansion space. The pre-combusted gases avoid the tendency of a renewed detonation front in the expansion space, especially one caused by a reflection off the end wall of the expansion space furthest away from the arresting device. In this way, the length of the expansion space can be reduced. In still further embodiments of the present invention, several pipe stubs are provided, where each of the pipe stubs have a smaller diameter than the diameter of the pipeline.
- 18. Preferably, the flame-arresting device has a total diameter of at least double the front impingement diameter so that low pressure drops are achieved during normal operations. A lower limit for the reduction of the gap between the end of the pipe stub and the flame-arresting device results from the need that, during normal operations, the total cross-section of the flame-arresting device be uniformly impinged at the usual, normally relatively low, flow velocities. Within the limits of these boundary conditions, the distance between the outlet of the pipe stub and the flame-arresting device is equal to or larger than one third of the pipe diameter and equal to or smaller than the pipe diameter.
- 19. The detonation front is expanded before reaching the flame-arresting device in such a manner that a deflagration ensues and impinges on the outer cross-section of the flame-arresting device. In the embodiments of the present invention, a small portion of the detonation front is diverted to an expansion space for pre-burning so that pre-combusted gases can prevent a renewed formation of a detonation front in the expansion space.
- 20. By using the configuration of the present invention, the detonation safety device of the present invention may be used without a shock buffer.
- 21. The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which:
- 22.FIG. 1 shows a flame-arresting device of the present invention;
- 23.FIG. 2 shows an expansion of a deflagration front initiated by secondary ignition by the detonation front;
- 24.FIG. 3 shows the flame-arresting device of the present invention under normal operating conditions;
- 25.FIG. 4 shows the flame-arresting device of the present invention with detonation fronts in both flow directions;
- 26.FIG. 5 shows the flame-arresting device of FIG. 1 with narrow slots;
- 27.FIG. 6 shows the flame-arresting device of FIG. 1 with openings on a pipe;
- 28.FIG. 7 shows the flame-arresting device of FIG. 1 with several pipe stubs of smaller diameter;
- 29.FIG. 8 shows the flame-arresting device of the present invention under normal operating conditions according to FIG. 7;
- 30.FIG. 9 shows the flame-arresting device of FIG. 1 with two pipe stubs of smaller diameter; and
- 31.FIG. 10 shows the flame-arresting device of the present invention under normal operating conditions according to FIG. 9.
- 32. Referring now to the drawings, and more particularly to FIG. 1, there is shown a detonation safety device of the present invention. The detonation safety device includes a
housing 2 which is inserted into apipeline 1. Thehousing 2 is flanged at both ends to thepipeline 1 thereby creating aninner space 3 of thehousing 2. The preferred shape of thehousing 2 is cylindrical with a cross-section approximately equal to that of the flame-arrestingdevice 5. - 33. A
pipe stub 4 extends from one end of thepipeline 1 into theinner space 3, and extends to a flame-arrestingdevice 5 mounted concentrically with thehousing 2. In the preferred embodiment, the flame-arrestingdevice 5 is mounted between two halves 6 of thehousing 2 and is secured byflange connections 7. - 34.FIG. 1 further shows a
detonation front 8 traveling through thepipe stub 4 and impinging upon aportion 9 of theflame arresting device 5. The flame-arrestingdevice 5 includes a diameter larger than the pipe and the detonation front such that the detonation front impinges only on a partial surface (e.g., portion 9) of the flame-arrestingdevice 5. Preferably, the flame-arrestingdevice 5 has a total diameter of at least double the front impingement diameter so that low pressure drops are achieved during normal operations. - 35.FIG. 2 shows an expansion of a deflagration front initiated by secondary ignition by the detonation front. Specifically, the detonation front impinges on the partial surface of the flame-arresting
device 5 and then expands in front of the arrestingdevice 5 so as to create a deflagration. The deflagration then impinges on the outer cross-section of the flame arresting device. - 36.FIG. 2 also shows that the
pipe stub 4 includes a diameter D, and that thedetonation front 8 impinges only on aportion 9 of the flame arresting device 5 (substantially equal to the diameter D of the pipeline 1). The diameter of theportion 9 of theflame arresting device 5 is approximately equal to the diameter D of thepipeline 1. The detonation front which impinges upon only theportion 9 of the flame-arrestingdevice 5 is subject to high flow resistance. This can be further reinforced by constructing the flame-arrestingdevice 5 so that the impingement section (e.g., portion 9) is different from the peripheral sections of the flame-arrestingdevice 5. - 37. As seen further in FIG. 2, the shock wave of
detonation front 8 encounters a relatively high flow resistance at theflame arresting device 5 due to the small diameter D. Thus, thedetonation front 8 is partially reflected by the flame-arrestingdevice 5 and is brought to extinction upon entering theportion 9 of the flame-arrestingdevice 5. Thedetonation front 8 also creates a secondary ignition in theexpansion space 13 of the housing 6 located in the open area between the end of thepipe stub 4 and the flame-arrestingdevice 5. Theexpansion space 13 extends for a distance L1 between the outlet of thepipe stub 4 to anend wall 10 of the housing 6. - 38. The secondary ignition of FIG. 2 creates a deflagration in the
expansion space 13. This deflagration further impinges on the outer periphery portions of the flame-arrestingdevice 5 which significantly lowers the flame propagation velocity and combustion pressure. The deflagration reflections from the walls of theexpansion space 13, especially theend wall 10 surrounding thepipe stub 4, could again initiate a detonation front. However, by using an adequate minimum length L1, the detonation front is eliminated since the reflected deflagration front transformed into a detonation front encounters an already combusted gas mixture in front of the flame-arrestingdevice 5. Thus, the detonation front is rendered harmless. - 39. In the preferred embodiment, length L1 is larger or equal to 0.5 D and smaller or equal to 2 D and more preferably equal to 0.6 D of the
pipeline 1; however, other appropriate lengths may equally be used depending on the pressure drop across the arrestingdevice 5. It is noted that when pre-combustion occurs, the length L1 may be reduced to one half of the pipeline diameter D. - 40. The detonation front is allowed to impinge only on a portion of the flame-arresting
device 5 by conducting the detonation front very close to the flame-arrestingdevice 5 by use of thepipe stub 4. Thus, an expansion space is created on the inlet side of the flame-arrestingdevice 5 which permits the detonation front to generate a deflagration, by secondary combustion. Since the flame-arrestingdevice 5 is impinged by the detonation front only on a part of the flame-arrestingdevice 5 surface it offers very high flow resistance. The free cross-section surface of the whole flame-arrestingdevice 5 is preferably equal or greater than the pipe diameter D of thepipeline 1. - 41. Referring now to FIG. 3, the cross-section of the flame-arresting
device 5 is either equal to or larger than the cross-section area of pipe stub 4 (diameter D) so thatnormal gas flow 11, rather than thedetonation front 8, does not cause any significant pressure loss across the flame-arrestingdevice 5. FIG. 3 further shows the open distance L2 between the outlet end of thepipe stub 4 and the flame-arrestingdevice 5 surface. The distance L2 is chosen such that under normal operation conditions the flame-arrestingdevice 5 is uniformly impinged by the flowing medium over the entire surface area of the flame-arrestingdevice 5. This takes place when L2 is larger or equal to one third of diameter D and smaller or equal to than diameter D. However, it is further understood that the distance L2 may obtain an optimal length depending on the pressure drop across the arrestingdevice 5. - 42.FIG. 4 shows the flame-arresting
device 5 of the present invention with detonation fronts in both flow directions. Specifically, FIG. 4 shows thepipe stub 4 provided on both sides offlame arresting device 5. Thus, the detonation safety device of FIG. 4 may be used fordetonation fronts 8 traveling in either direction. - 43.FIG. 5 shows the flame-arresting
device 5 withnarrow slots 9′ about the center thereof and substantially directly in the path of the detonation front. Thenarrow slots 9′ of the flame-arrestingdevice 5 provides a higher flow resistance to thedetonation front 8 as compared to the slots of FIG. 1. It is advantageous for theslots 9′ in the impingement area to be narrower, while for reason of manufacturing the slot lengths of all of the slots are uniform over the whole flame-arrestingdevice 5 cross-section. - 44. Referring now to FIG. 6, the
pipe stub 4 is provided withsmall connection openings 12 that divert a portion of the enteringdetonation front 8 immediately after the beginning ofhousing 2. Theconnection openings 12 transfer thedetonation front 8 directly into theexpansion space 13 which causes pre-combustion of the detonation front in theexpansion space 13. The burnt gases in theexpansion space 13 hinder the generation of a secondary detonation by reflection of a deflagration off theend wail 10 of thehousing 2 which results in a reduction in the length L1. - 45.FIG. 7 shows
several pipe stubs 4′ each having a smaller diameters than diameter D (as shown in FIG. 1) of thepipeline 1. The arrangement of thepipe stubs 4′ shown in FIG. 7 includes acentral stub 4′ aligned with thepipeline 1 but having a slightly smaller diameter D than that of thepipeline 1. Fouradditional pipe stubs 4′ are placed radially from thecentral stub 4′ at equal distances from each other. As seen in FIG. 7, the flame-arrestingdevice 5 is extremely large in relation to the diameter of thepipe stubs 4′ which allows the flame-arrestingdevice 5 to obtain a very low pressure loss through during normal operation. It is further noted that the effective gap length L2 is maintained and that a uniform distribution of the flowing medium on the flame-arrestingdevice 5 during normal operation is obtain when theseveral pipe stubs 4′ are installed opposite the cross-section of the flame-arrestingdevice 5. - 46. Still referring to FIG. 7, the
detonation front 8 traveling through thepipeline 1 is split into severalpartial detonation fronts 8′ that impinge on the correspondingportions 9″ of the flame-arrestingdevice 5. Also, the back end-wall 10′, limiting the length L1 of theexpansion space 13, is formed by wall pieces that create adistribution space 14 in the flow direction in front of the flame-arrestingdevice 5. Thisexpansion space 13 spreads from the diameter D of thepipeline 1 to the effective diameter of the flame-arrestingdevice 5, and further includes thepipe stubs 4′. FIG. 8 shows the normal operation of the flame-arrestingdevice 5 such that normal part-streams 11′ pass through thestubs 4′ and are distributed uniformly on the cross-section surface of the arrestingdevice 5. - 47.FIG. 9 shows two
pipe stubs 4′ which are placed equidistant from the center axis of thehousing 2 and/or the flame-arrestingdevice 5. This arrangement also leads topartial detonation fronts 8′ of FIG. 9 and/or normal part-flows as shown in FIG. 10. - 48. While the invention has been described in terms of a single preferred embodiment, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims.
Claims (21)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/756,915 US6409779B2 (en) | 1998-04-25 | 2001-01-10 | Method for rendering a detonation front harmless |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19818572.3 | 1998-04-25 | ||
DE19818572 | 1998-04-25 | ||
DE19818572A DE19818572C1 (en) | 1998-04-25 | 1998-04-25 | Process for rendering a detonation front harmless and detonation protection |
US09/296,405 US6342082B1 (en) | 1998-04-25 | 1999-04-23 | Apparatus for rendering a detonation front harmless |
US09/756,915 US6409779B2 (en) | 1998-04-25 | 2001-01-10 | Method for rendering a detonation front harmless |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/296,405 Division US6342082B1 (en) | 1998-04-25 | 1999-04-23 | Apparatus for rendering a detonation front harmless |
Publications (2)
Publication Number | Publication Date |
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US20010000837A1 true US20010000837A1 (en) | 2001-05-10 |
US6409779B2 US6409779B2 (en) | 2002-06-25 |
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Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/296,405 Expired - Fee Related US6342082B1 (en) | 1998-04-25 | 1999-04-23 | Apparatus for rendering a detonation front harmless |
US09/756,915 Expired - Fee Related US6409779B2 (en) | 1998-04-25 | 2001-01-10 | Method for rendering a detonation front harmless |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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US09/296,405 Expired - Fee Related US6342082B1 (en) | 1998-04-25 | 1999-04-23 | Apparatus for rendering a detonation front harmless |
Country Status (17)
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US (2) | US6342082B1 (en) |
EP (1) | EP0951922B1 (en) |
JP (1) | JP4146024B2 (en) |
KR (1) | KR100603689B1 (en) |
AT (1) | ATE313357T1 (en) |
BR (1) | BR9901255A (en) |
CA (1) | CA2269010C (en) |
CZ (1) | CZ296165B6 (en) |
DE (2) | DE19818572C1 (en) |
DK (1) | DK0951922T3 (en) |
ES (1) | ES2251127T3 (en) |
HU (1) | HU220978B1 (en) |
NO (1) | NO317802B1 (en) |
PL (1) | PL188748B1 (en) |
SI (1) | SI0951922T1 (en) |
SK (1) | SK284694B6 (en) |
TW (1) | TW427919B (en) |
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US20120189966A1 (en) * | 2011-01-21 | 2012-07-26 | Brooker Dwight E | Detonation flame arrestor including a transition point/attenuation matrix and torturous path media |
US20120279197A1 (en) * | 2007-12-04 | 2012-11-08 | Firestar Engineering, Llc | Nitrous oxide flame barrier |
CN104274929A (en) * | 2014-02-23 | 2015-01-14 | 精凯(天津)阀门制造有限公司 | Detonating type flame arrester |
CN106170320A (en) * | 2014-01-28 | 2016-11-30 | 埃尔马克科技有限公司 | Spark arrester |
CN107842389A (en) * | 2017-11-06 | 2018-03-27 | 中煤科工集团重庆研究院有限公司 | Has the gas drainage under suction fire retardant device of self-cleaning function |
CN108379761A (en) * | 2018-05-02 | 2018-08-10 | 抚顺华油能源设备厂 | Damp spark arrester |
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DE19957836B4 (en) * | 1999-11-25 | 2004-05-27 | RMG - Gaselan Regel + Meßtechnik GmbH | Method and device for damping the pressure surge on flame arresters during detonations |
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SK32016A3 (en) * | 2016-01-20 | 2017-08-02 | Malad S.R.O. | Rectifier of symmetrical fluid flow in pipeline |
GB201707857D0 (en) * | 2017-05-16 | 2017-06-28 | Elmac Tech Ltd | Valve apparatus |
CN110314306A (en) * | 2019-05-17 | 2019-10-11 | 普瑞泰格(南京)安全设备有限公司 | A kind of two-way explosion arrestment Hong fire arrester |
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DE1192982B (en) | 1958-09-02 | 1965-05-13 | Wilhelm Lepper Dr Ing | Centrifuge with unbalance compensation |
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CA2032791C (en) * | 1990-12-20 | 1994-08-30 | Robert Carl Rajewski | Detonation arrestor |
US5402603A (en) * | 1992-01-03 | 1995-04-04 | Henley; Robert L. | Flapper plate detonation flame arrester |
DE19536292C2 (en) * | 1995-09-29 | 1997-09-25 | Leinemann Gmbh & Co | Method and device for reducing a detonation in a container or piping system |
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- 1998-04-25 DE DE19818572A patent/DE19818572C1/en not_active Expired - Fee Related
-
1999
- 1999-03-13 EP EP99105224A patent/EP0951922B1/en not_active Expired - Lifetime
- 1999-03-13 DE DE59912942T patent/DE59912942D1/en not_active Expired - Lifetime
- 1999-03-13 DK DK99105224T patent/DK0951922T3/en active
- 1999-03-13 SI SI9930874T patent/SI0951922T1/en unknown
- 1999-03-13 ES ES99105224T patent/ES2251127T3/en not_active Expired - Lifetime
- 1999-03-13 AT AT99105224T patent/ATE313357T1/en active
- 1999-03-24 TW TW088104649A patent/TW427919B/en not_active IP Right Cessation
- 1999-03-25 NO NO19991454A patent/NO317802B1/en not_active IP Right Cessation
- 1999-03-26 SK SK414-99A patent/SK284694B6/en not_active IP Right Cessation
- 1999-03-29 JP JP08646799A patent/JP4146024B2/en not_active Expired - Fee Related
- 1999-04-14 CZ CZ0131199A patent/CZ296165B6/en not_active IP Right Cessation
- 1999-04-14 CA CA002269010A patent/CA2269010C/en not_active Expired - Fee Related
- 1999-04-15 BR BR9901255A patent/BR9901255A/en not_active IP Right Cessation
- 1999-04-20 HU HU9901267A patent/HU220978B1/en not_active IP Right Cessation
- 1999-04-20 PL PL99332619A patent/PL188748B1/en not_active IP Right Cessation
- 1999-04-23 US US09/296,405 patent/US6342082B1/en not_active Expired - Fee Related
- 1999-04-23 KR KR1019990014631A patent/KR100603689B1/en not_active IP Right Cessation
-
2001
- 2001-01-10 US US09/756,915 patent/US6409779B2/en not_active Expired - Fee Related
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US20120279197A1 (en) * | 2007-12-04 | 2012-11-08 | Firestar Engineering, Llc | Nitrous oxide flame barrier |
US20120189966A1 (en) * | 2011-01-21 | 2012-07-26 | Brooker Dwight E | Detonation flame arrestor including a transition point/attenuation matrix and torturous path media |
CN106170320A (en) * | 2014-01-28 | 2016-11-30 | 埃尔马克科技有限公司 | Spark arrester |
US10143869B2 (en) | 2014-01-28 | 2018-12-04 | Elmac Technologies Limited | Flame arresters |
US11724138B2 (en) | 2014-01-28 | 2023-08-15 | Elmac Technologies Limited | Flame arresters |
CN104274929A (en) * | 2014-02-23 | 2015-01-14 | 精凯(天津)阀门制造有限公司 | Detonating type flame arrester |
CN107842389A (en) * | 2017-11-06 | 2018-03-27 | 中煤科工集团重庆研究院有限公司 | Has the gas drainage under suction fire retardant device of self-cleaning function |
CN108379761A (en) * | 2018-05-02 | 2018-08-10 | 抚顺华油能源设备厂 | Damp spark arrester |
US11465003B2 (en) * | 2018-07-18 | 2022-10-11 | Jiangsu University | Buffered wall flow multi-channels flame arrester |
CN109764245A (en) * | 2019-02-19 | 2019-05-17 | 常州港华燃气有限公司 | Compound explosion suppression type natural gas line explosion-proof fire-extinguishing device |
Also Published As
Publication number | Publication date |
---|---|
EP0951922A3 (en) | 2001-07-25 |
NO991454L (en) | 1999-10-26 |
CZ296165B6 (en) | 2006-01-11 |
DE59912942D1 (en) | 2006-01-26 |
CA2269010C (en) | 2006-08-01 |
SK284694B6 (en) | 2005-09-08 |
SK41499A3 (en) | 2000-02-14 |
TW427919B (en) | 2001-04-01 |
US6342082B1 (en) | 2002-01-29 |
HU9901267D0 (en) | 1999-06-28 |
NO317802B1 (en) | 2004-12-13 |
PL188748B1 (en) | 2005-04-29 |
EP0951922A2 (en) | 1999-10-27 |
EP0951922B1 (en) | 2005-12-21 |
CA2269010A1 (en) | 1999-10-25 |
HU220978B1 (en) | 2002-07-29 |
JPH11311500A (en) | 1999-11-09 |
ATE313357T1 (en) | 2006-01-15 |
PL332619A1 (en) | 1999-11-08 |
DK0951922T3 (en) | 2006-04-10 |
KR100603689B1 (en) | 2006-07-20 |
CZ131199A3 (en) | 1999-11-17 |
SI0951922T1 (en) | 2006-04-30 |
NO991454D0 (en) | 1999-03-25 |
ES2251127T3 (en) | 2006-04-16 |
DE19818572C1 (en) | 1999-11-11 |
KR19990087958A (en) | 1999-12-27 |
JP4146024B2 (en) | 2008-09-03 |
US6409779B2 (en) | 2002-06-25 |
BR9901255A (en) | 2000-03-21 |
HUP9901267A1 (en) | 2000-05-28 |
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