US20020020323A1 - Device to minimize the explosive effects of a metal casing in the event of accidental internal overpressure - Google Patents
Device to minimize the explosive effects of a metal casing in the event of accidental internal overpressure Download PDFInfo
- Publication number
- US20020020323A1 US20020020323A1 US09/893,448 US89344801A US2002020323A1 US 20020020323 A1 US20020020323 A1 US 20020020323A1 US 89344801 A US89344801 A US 89344801A US 2002020323 A1 US2002020323 A1 US 2002020323A1
- Authority
- US
- United States
- Prior art keywords
- casing
- pyrotechnic system
- attached
- event
- minimize
- Prior art date
- 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.)
- Abandoned
Links
- 239000002184 metal Substances 0.000 title claims description 8
- 230000000694 effects Effects 0.000 title claims description 4
- 239000002360 explosive Substances 0.000 title claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000011810 insulating material Substances 0.000 claims description 3
- 230000015556 catabolic process Effects 0.000 claims description 2
- 238000006731 degradation reaction Methods 0.000 claims description 2
- 238000001514 detection method Methods 0.000 claims description 2
- 239000000126 substance Substances 0.000 claims description 2
- 239000000203 mixture Substances 0.000 abstract description 13
- 230000009172 bursting Effects 0.000 abstract 2
- 239000012634 fragment Substances 0.000 abstract 1
- 238000013467 fragmentation Methods 0.000 abstract 1
- 238000006062 fragmentation reaction Methods 0.000 abstract 1
- 206010061218 Inflammation Diseases 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000004054 inflammatory process Effects 0.000 description 3
- 230000002269 spontaneous effect Effects 0.000 description 3
- 238000004880 explosion Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000005062 Polybutadiene Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000013021 overheating Methods 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B39/00—Packaging or storage of ammunition or explosive charges; Safety features thereof; Cartridge belts or bags
- F42B39/20—Packages or ammunition having valves for pressure-equalising; Packages or ammunition having plugs for pressure release, e.g. meltable ; Blow-out panels; Venting arrangements
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B39/00—Packaging or storage of ammunition or explosive charges; Safety features thereof; Cartridge belts or bags
- F42B39/14—Explosion or fire protection arrangements on packages or ammunition
Definitions
- the present invention pertains to a device for minimizing the explosive effects of a metal casing in the event of an accidental rise in internal pressure.
- Certain missile thrusters have a metal structure and react violently when subjected to heating because of surrounding fire. In this case, a large number of significantly sized splinters of the metal structure are violently thrown out over long distances. This reaction results from the combination of two phenomena:
- An object of the present invention is a device to minimize the explosive effects of a metal casing subjected to internal overpressure, for example a missile thruster casing that gets excessively pressurized if it is subjected to a fire, this device being easily adaptable to different sorts of casings while being inexpensive and efficient in almost every instance.
- the device according to the invention comprises a pyrotechnic system attached to the casing that is activated immediately upon detection of a phenomenon that causes a rise in overpressure in the casing.
- the ignition of this pyrotechnic system gives rise, by heating, to a limited local degradation of the mechanical characteristics of the casing.
- FIGURE is a partial sectional view of a missile thruster provided with the device according to the invention.
- the present invention is described here below with reference to a missile thruster that undergoes an accidental fire in its storage hangar, but it is clearly not limited to this single application and can be implemented in other applications comprising a metal casing, already pressurized internally, or else containing products that can place it under normal pressure or overpressure in the event of accidents, this overpressure prompting the explosion of the casing with violent outbursts of splinters from this casing.
- the thruster 1 shown in the single FIGURE essentially has a circular cylindrical casing 2 enclosing a coaxial internal central channel 3 , the space between this channel 3 and the casing 2 being filled with propergol 4 .
- the internal face of the casing is lined with a binding agent 7 known as liner, generally made of polybutadiene or polyurethane.
- a box 5 is attached to the external face of the casing 2 .
- This box 5 contains a pyrotechnic composition 6 .
- This pyrotechnic composition 6 when fired, releases a large quantity of calories, sufficient to locally degrade the mechanical properties of the casing to the point at which, when the propergol 4 undergoes spontaneous inflammation following its heating by a fire, the pressure thus generated in the casing does not have sufficient time to reach an excessively high value and cause the above-mentioned violent reaction.
- the composition 6 is a propergol composition or a pyrotechnic composition, and its volume is about 10 cm 3 for a steel casing about 1.5 mm thick and 10 cm long.
- the nature and quantity of the composition 6 are adapted to the characteristics of the casing 2 and of the propergol 4 .
- the ignition of the composition 6 can be either spontaneous following its heating due to the fire or activated by an appropriate ignition device connected to a heat sensor attached to the casing 2 .
- a layer of heat-insulating material is placed around the casing. This heat-insulating material is used to delay the heating of the propergol 4 to allow time for the composition 6 to sufficiently degrade the local mechanical characteristics of the casing 2 .
- the box 5 with the composition 6 is attached to the interior of the casing 2 , in contact with this casing.
- An embodiment of this kind although less simple to make than embodiment described here above, may have advantages in other applications, for example owing to the fact that the box 5 is not an “outgrowth” one the casing and hence does not risk getting accidentally wrenched off, for example during the handling of the casing, or does not in any way constitute a hindrance, for example when the casing is being shifted.
- the device of the invention prevents the violent explosion of a casing which either contains products capable of catching fire by spontaneous inflammation or exploding through an excessive heating of the casing or else is under internal pressure in normal conditions whereas, however, this internal pressure may rise exaggeratedly under normal conditions (over-heating, modification of the composition of the contents, internal short circuit etc.).
- the ignition of the compound 6 is activated spontaneously or by an appropriate sensor of physical or chemical conditions (such as a pressure sensor, temperature sensor, gas sensor etc.).
Abstract
To prevent the violent bursting of the casing of a thruster containing propergol during an accidental fire in its vicinity, a pyrotechnic composition (5, 6) is attached to this casing. This pyrotechnic composition locally heats the casing during this fire, and therefore embrittles this casing which opens at this place before the internal pressure becomes excessive. This prevents the fragmentation of the casing and the bursting out of the fragments.
Description
- The present invention pertains to a device for minimizing the explosive effects of a metal casing in the event of an accidental rise in internal pressure.
- Certain missile thrusters have a metal structure and react violently when subjected to heating because of surrounding fire. In this case, a large number of significantly sized splinters of the metal structure are violently thrown out over long distances. This reaction results from the combination of two phenomena:
- whatever the architecture of the thruster, the heating due to the fire prompts a pyrotechnic reaction on the part of the thrusters. The energy thus released prompts a rise in pressure in the casing of the thruster;
- simultaneously, the properties of mechanical resistance of the casing are not sufficiently weakened by the fire. The casing breaks at high pressure, giving rise to big metal splinters.
- An object of the present invention is a device to minimize the explosive effects of a metal casing subjected to internal overpressure, for example a missile thruster casing that gets excessively pressurized if it is subjected to a fire, this device being easily adaptable to different sorts of casings while being inexpensive and efficient in almost every instance.
- The device according to the invention comprises a pyrotechnic system attached to the casing that is activated immediately upon detection of a phenomenon that causes a rise in overpressure in the casing. The ignition of this pyrotechnic system gives rise, by heating, to a limited local degradation of the mechanical characteristics of the casing.
- The present invention will be understood more clearly from the following detailed description of an embodiment given by way of a non-restrictive example and illustrated by the appended drawing, wherein the single FIGURE is a partial sectional view of a missile thruster provided with the device according to the invention.
- The present invention is described here below with reference to a missile thruster that undergoes an accidental fire in its storage hangar, but it is clearly not limited to this single application and can be implemented in other applications comprising a metal casing, already pressurized internally, or else containing products that can place it under normal pressure or overpressure in the event of accidents, this overpressure prompting the explosion of the casing with violent outbursts of splinters from this casing.
- The thruster1 shown in the single FIGURE essentially has a circular
cylindrical casing 2 enclosing a coaxial internalcentral channel 3, the space between thischannel 3 and thecasing 2 being filled with propergol 4. In order to provide for firm adhesion between the propergol and the casing, the internal face of the casing is lined with abinding agent 7 known as liner, generally made of polybutadiene or polyurethane. - According to the invention, a
box 5 is attached to the external face of thecasing 2. Thisbox 5 contains apyrotechnic composition 6. Thispyrotechnic composition 6, when fired, releases a large quantity of calories, sufficient to locally degrade the mechanical properties of the casing to the point at which, when the propergol 4 undergoes spontaneous inflammation following its heating by a fire, the pressure thus generated in the casing does not have sufficient time to reach an excessively high value and cause the above-mentioned violent reaction. In fact, as soon as this internal pressure starts rising, while remaining relatively low (at a value that can be easily withstood by the casing under normal conditions), the part of the casing embrittled by the heavy heating due to thecomposition 6 opens, giving rise to practically no splinters at all, and lets out the pressurized gases produced by the inflammation of the propergol. - According to one embodiment of the invention, the
composition 6 is a propergol composition or a pyrotechnic composition, and its volume is about 10 cm3 for a steel casing about 1.5 mm thick and 10 cm long. Naturally, the nature and quantity of thecomposition 6 are adapted to the characteristics of thecasing 2 and of the propergol 4. - The ignition of the
composition 6 can be either spontaneous following its heating due to the fire or activated by an appropriate ignition device connected to a heat sensor attached to thecasing 2. - According to another characteristic of the invention, a layer of heat-insulating material is placed around the casing. This heat-insulating material is used to delay the heating of the propergol4 to allow time for the
composition 6 to sufficiently degrade the local mechanical characteristics of thecasing 2. - According to one variant of the invention, the
box 5 with thecomposition 6 is attached to the interior of thecasing 2, in contact with this casing. An embodiment of this kind, although less simple to make than embodiment described here above, may have advantages in other applications, for example owing to the fact that thebox 5 is not an “outgrowth” one the casing and hence does not risk getting accidentally wrenched off, for example during the handling of the casing, or does not in any way constitute a hindrance, for example when the casing is being shifted. - In general, the device of the invention prevents the violent explosion of a casing which either contains products capable of catching fire by spontaneous inflammation or exploding through an excessive heating of the casing or else is under internal pressure in normal conditions whereas, however, this internal pressure may rise exaggeratedly under normal conditions (over-heating, modification of the composition of the contents, internal short circuit etc.). In such cases, the ignition of the
compound 6 is activated spontaneously or by an appropriate sensor of physical or chemical conditions (such as a pressure sensor, temperature sensor, gas sensor etc.).
Claims (7)
1. A device for minimizing the explosive effects of a metal casing subjected to internal overpressure, comprising a pyrotechnic system attached to the casing that is activated immediately upon detection of a phenomenon that causes a rise in overpressure in the casing, the ignition of this pyrotechnic system causing a limited local degradation, through heating, of the mechanical characteristics of the casing.
2. A device according to claim 1 , wherein the pyrotechnic system is attached to the exterior of the casing, in contact with it.
3. A device according to claim 1 , wherein the pyrotechnic system is attached to the interior of the casing, in contact with it.
4. A device according to claim 1 , 2 or 3, wherein the ignition of the pyrotechnic system is prompted by heating.
5. A device according to one of the claims 1 to 3 , wherein the ignition of the pyrotechnic system is activated by a sensor of physical or chemical conditions.
6. A device according to one of the above claims, wherein the casing is lined with a layer of heat-insulating material.
7. A device according to one of the above claims, wherein the casing is that of a missile thruster.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR0008516 | 2000-06-30 | ||
FR0008516A FR2811053B1 (en) | 2000-06-30 | 2000-06-30 | DEVICE FOR MINIMIZING THE EXPLOSION EFFECTS OF A METAL ENCLOSURE IN THE EVENT OF ACCIDENTAL INTERNAL OVERPRESSURE |
Publications (1)
Publication Number | Publication Date |
---|---|
US20020020323A1 true US20020020323A1 (en) | 2002-02-21 |
Family
ID=8851961
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/893,448 Abandoned US20020020323A1 (en) | 2000-06-30 | 2001-06-29 | Device to minimize the explosive effects of a metal casing in the event of accidental internal overpressure |
Country Status (4)
Country | Link |
---|---|
US (1) | US20020020323A1 (en) |
EP (1) | EP1170568A3 (en) |
FR (1) | FR2811053B1 (en) |
NO (1) | NO20013225L (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6952995B2 (en) * | 2002-01-11 | 2005-10-11 | Aerojet-General Corporation | Apparatus and method for passive venting of rocket motor or ordnance case |
WO2005116573A1 (en) * | 2004-05-25 | 2005-12-08 | Lockheed Martin Corporation | Thermally-initiated venting system and method of using same |
EP1624178A1 (en) * | 2004-08-05 | 2006-02-08 | Diehl BGT Defence GmbH & Co.KG | Rocket motor |
US7472653B1 (en) * | 2006-06-15 | 2009-01-06 | United States Of America As Represented By The Secretary Of The Navy | Insensitive munitions warhead explosive venting system |
US20110056363A1 (en) * | 2008-04-30 | 2011-03-10 | Saab Ab | Weapon with im-characteristics |
US20120240808A1 (en) * | 2009-07-17 | 2012-09-27 | Tda Armements Sas | Ammunition Comprising Means for Neutralizing Its Explosive Charge |
US9255774B2 (en) | 2008-06-30 | 2016-02-09 | Battelle Memorial Institute | Controlled fragmentation of a warhead shell |
US10670381B1 (en) * | 2013-09-17 | 2020-06-02 | The United States Of America, As Represented By The Secretary Of The Navy | Electronic thermally-initiated venting system (ETIVS) for rocket motors |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2908506B1 (en) | 2006-11-14 | 2008-12-19 | Protac | PROTECTIVE SYSTEM FOR DEVICE CONTAINING MATERIAL WHICH RESULTS AGAINST WARMING |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5206456A (en) * | 1989-08-24 | 1993-04-27 | The United States Of America As Represented By The Secretary Of The Navy | Ordinance thermal battery |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4478151A (en) * | 1983-02-28 | 1984-10-23 | The United States Of America As Represented By The Secretary Of The Navy | Pressure vessel penetrator |
US4597261A (en) * | 1984-05-25 | 1986-07-01 | Hughes Aircraft Company | Thermally actuated rocket motor safety system |
US5129326A (en) * | 1987-04-14 | 1992-07-14 | Aerojet-General Corporation | Ordnance device with explosion protection |
-
2000
- 2000-06-30 FR FR0008516A patent/FR2811053B1/en not_active Expired - Fee Related
-
2001
- 2001-06-26 EP EP01401693A patent/EP1170568A3/en not_active Withdrawn
- 2001-06-27 NO NO20013225A patent/NO20013225L/en not_active Application Discontinuation
- 2001-06-29 US US09/893,448 patent/US20020020323A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5206456A (en) * | 1989-08-24 | 1993-04-27 | The United States Of America As Represented By The Secretary Of The Navy | Ordinance thermal battery |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6952995B2 (en) * | 2002-01-11 | 2005-10-11 | Aerojet-General Corporation | Apparatus and method for passive venting of rocket motor or ordnance case |
EP3327401A1 (en) * | 2004-05-25 | 2018-05-30 | Lockheed Martin Corporation | Thermally-initiated venting system and method of using same |
WO2005116573A1 (en) * | 2004-05-25 | 2005-12-08 | Lockheed Martin Corporation | Thermally-initiated venting system and method of using same |
US20070240600A1 (en) * | 2004-05-25 | 2007-10-18 | Skinner Anthony T | Thermally initiated venting system and method of using same |
US7530314B2 (en) | 2004-05-25 | 2009-05-12 | Lockheed Martin Corporation | Thermally initiated venting system and method of using same |
EP1624178A1 (en) * | 2004-08-05 | 2006-02-08 | Diehl BGT Defence GmbH & Co.KG | Rocket motor |
US7472653B1 (en) * | 2006-06-15 | 2009-01-06 | United States Of America As Represented By The Secretary Of The Navy | Insensitive munitions warhead explosive venting system |
US20110056363A1 (en) * | 2008-04-30 | 2011-03-10 | Saab Ab | Weapon with im-characteristics |
US7913608B1 (en) | 2008-04-30 | 2011-03-29 | Saab Ab | Weapon with IM-characteristics |
US9255774B2 (en) | 2008-06-30 | 2016-02-09 | Battelle Memorial Institute | Controlled fragmentation of a warhead shell |
US9541363B2 (en) | 2008-06-30 | 2017-01-10 | Battelle Memorial Institute | Controlled fragmentation of a warhead shell |
US20120240808A1 (en) * | 2009-07-17 | 2012-09-27 | Tda Armements Sas | Ammunition Comprising Means for Neutralizing Its Explosive Charge |
US8584588B2 (en) * | 2009-07-17 | 2013-11-19 | Tda Armements Sas | Ammunition comprising means for neutralizing its explosive charge |
US10670381B1 (en) * | 2013-09-17 | 2020-06-02 | The United States Of America, As Represented By The Secretary Of The Navy | Electronic thermally-initiated venting system (ETIVS) for rocket motors |
Also Published As
Publication number | Publication date |
---|---|
NO20013225D0 (en) | 2001-06-27 |
EP1170568A3 (en) | 2002-04-03 |
EP1170568A2 (en) | 2002-01-09 |
NO20013225L (en) | 2001-12-31 |
FR2811053B1 (en) | 2003-06-13 |
FR2811053A1 (en) | 2002-01-04 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: PROTAC, FRANCE Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:DASSIS, OLIVIER;REEL/FRAME:012259/0205 Effective date: 20010926 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |