IL108819A - Rocket motor protection device during slow cook-off test - Google Patents
Rocket motor protection device during slow cook-off testInfo
- Publication number
- IL108819A IL108819A IL10881994A IL10881994A IL108819A IL 108819 A IL108819 A IL 108819A IL 10881994 A IL10881994 A IL 10881994A IL 10881994 A IL10881994 A IL 10881994A IL 108819 A IL108819 A IL 108819A
- Authority
- IL
- Israel
- Prior art keywords
- rocket motor
- test
- predetermined
- slow cook
- ignition
- Prior art date
Links
- 239000008188 pellet Substances 0.000 claims description 21
- 239000003380 propellant Substances 0.000 claims description 20
- 239000002131 composite material Substances 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 10
- 239000004033 plastic Substances 0.000 claims description 8
- 230000001141 propulsive effect Effects 0.000 claims description 8
- 239000002360 explosive Substances 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 4
- 239000000843 powder Substances 0.000 claims description 4
- 239000000654 additive Substances 0.000 claims description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 2
- 239000000020 Nitrocellulose Substances 0.000 claims description 2
- SNIOPGDIGTZGOP-UHFFFAOYSA-N Nitroglycerin Chemical compound [O-][N+](=O)OCC(O[N+]([O-])=O)CO[N+]([O-])=O SNIOPGDIGTZGOP-UHFFFAOYSA-N 0.000 claims description 2
- 239000004809 Teflon Substances 0.000 claims description 2
- 229920006362 Teflon® Polymers 0.000 claims description 2
- SOCJRBYNJRVWAB-UHFFFAOYSA-N [Cr](=O)(=O)([O-])[O-].[Ba+2].[B+3] Chemical compound [Cr](=O)(=O)([O-])[O-].[Ba+2].[B+3] SOCJRBYNJRVWAB-UHFFFAOYSA-N 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims description 2
- 229960003711 glyceryl trinitrate Drugs 0.000 claims description 2
- 229920001220 nitrocellulos Polymers 0.000 claims description 2
- 239000002245 particle Substances 0.000 claims description 2
- 238000006243 chemical reaction Methods 0.000 description 9
- GDDNTTHUKVNJRA-UHFFFAOYSA-N 3-bromo-3,3-difluoroprop-1-ene Chemical compound FC(F)(Br)C=C GDDNTTHUKVNJRA-UHFFFAOYSA-N 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 239000000779 smoke Substances 0.000 description 3
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 235000015842 Hesperis Nutrition 0.000 description 1
- 235000012633 Iberis amara Nutrition 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000004200 deflagration Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000004449 solid propellant Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229960005088 urethane Drugs 0.000 description 1
- 238000013022 venting Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06C—DETONATING OR PRIMING DEVICES; FUSES; CHEMICAL LIGHTERS; PYROPHORIC COMPOSITIONS
- C06C9/00—Chemical contact igniters; Chemical lighters
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/32—Constructional parts; Details not otherwise provided for
- F02K9/34—Casings; Combustion chambers; Liners thereof
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K9/00—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof
- F02K9/08—Rocket-engine plants, i.e. plants carrying both fuel and oxidant therefor; Control thereof using solid propellants
- F02K9/32—Constructional parts; Details not otherwise provided for
- F02K9/38—Safety devices, e.g. to prevent accidental ignition
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Air Bags (AREA)
- Aiming, Guidance, Guns With A Light Source, Armor, Camouflage, And Targets (AREA)
Description
"ROCKiT MOTOR PROTECTION DEVICE DURING SLOW COOK-OFF TEST" " ΌΉ Dl»»n η,7«Τ2 i 'Op~t yi3D ||7Jin" THE APPLICANT: :n¾W1Dn STATE OP ISRAEL, , "7N~Hi» 1 I13«TD Ministry of Defense, ( "ND1) n»»n7 'y_iDN nin»D7 niunn Armament Development Authority, .31021 nD'n ,2250 .i.n P.O.Box 2250, Haifa 31021.
THE INVENTORS: 1. Dr. Moshe GILL "7» 3 nWD .1 P.O.Box 2500 2500 .T.n Haifa 31021 31021 nam 2. Dr. Itzhak AVNON I 132N |7n^» T'T .2 P.O.Box 2500 2500 .T.n Haifa 31021 31021 nD»n 3. Yehuda KATZ YD mini .3 13, Kalisher St. 13 -mt7p nm Haifa 32712 32712 n «n 4. Dr. Tamar YAROM DIT on Ύ'Ί .4 23, Armonim St. 23 onio y mm Kiryat Bialik 27230. .27230 | ' 7N » 2=JV TP The present invention relates to a safety mechanism for rocket motors. More particularly, the invention relates to a protective slow cook-off mechanism for providing automatically protection by ignition of a rocket motor, to be non-explosive and non-propulsive.
BACKGROUND OF THE INVENTION.
The slow cook-off test is a well-known test included in the Insensitive Munitions program. The purpose of this program is to develop munitions which fulfill their performance and operational requirements, while minimizing the violence of the reaction and subsequent damage when subjected to any undesi red event. As known, one of the primary dangers from storing rockets arises not from the explosion charge, but rather from the rocket motor itself. The slow cook-off test is used to determine the reaction temperature and to measure the overal 1 response of major munition subsystems to a gradually increasing thermal environment, this test consists of subjecting the respective item to be tested, to a gradually ncreasing temperature at a rate of 6°F per hour until a reaction occurs. The item to be tested may be precond tioned at the munition's upper environmental temperature limit for about eight hours prior to the start of the test.
Reduced smoke composite propel lants, are based on ammonium perchlorate and an elastomeric plastic such as ure- thane cured polybutadiene, which burn vigorously at low pressure and are difficult to extinguish. Moreover, the composite propellants tend to react very violent in the slow cook-off test itself, even with minimal confinement. The reaction involves an explosion deflagration which destroys the case and breaks up the steel oven walls into several fragments.
A method to prevent the violent reaction of rocket motor containing a metallic housing during the slow cooking-off test is suggested in the U.S. Patent Number 4,961,313. According to this method, the slow cook-off trigger mechanism is thermally coupled to a bimetallic snap action disc spring.
Another method, as described in the recent Patent Number 5,044,154, suggests as a safety mechanism for rendering a rocket motor non-propulsive a casing made from segments which are attached together. A retaining member which extends c rcumferential ly thereabout, possesses a sensitivity to a predetermined initiated temperature. This temperature is higher than the ambient one, but lower than the ignition temperature of the propellant material in the rocket motor. In this manner, it will loose its strength when the retaining member is released and thus the rocket motor may safely be rendered non-propulsive during a slow cook-off test.
In the European Patent No. 381,753, a slow cook-off protection is suggested for a rocket motor having a metallic housing. The safety apparatus comprises a trigger working by a bimetallic snap-action spring to sense the temperature of the ambient environment and generate a mechanical response when the temperature reaches a predetermined temperature. The trigger ignites a charge which creates a stress riser and deactivates the propulsion thrust capability in response to the mechanical response. It is claimed that the safety apparatus prevents slow cook-off hazard of a rocket.
The main disadvantage of the known devices is based on the fact that the violent reaction of composite propel-lants rocket motors during the slow cook-off test is almost independent of the casing and therefore, splitting the casing does not provide a good protection against slow cook-off test in such rocket motors. The extreme violence of ammonium perchlorate and an elastomeric binder composite propellant under the slow cook-off test, is mainly due to the partial decomposition of the propellant and particularly to that of the ammonium perchlorate. As known, ammonium perchlorate undergoes a partial decomposition, generating a porous, metastable product. This porous material tends to explode or to undergo a chemical reaction producing a vigorous evolution of heat and flame which moves through the material, upon ignition at high temperature.
It is an object of the present invention to provide a device for imparting protection during a slow cook-off test for a rocket motor casing made from a composite material. It is another object of the present invention, to provide a simple device for imparting a non-explosive reaction and non-propulsive property to a rocket motor containing a reduced smoke composite material during a slow cook-off test. It is yet another object of the present invention, to provide a simple device for imparting a non-explos ve reaction and a non-propuls ve property to a rocket motor containing a reduced smoke composite material which is reliable and inexpensive.
BRIEF DESCRIPTION OF THE INVENTION.
The invention relates to a device for imparting a non-explosive and non-propulsive properties to a rocket motor casing made from a composite material during a slow cook-off test, which consists of using a predetermined pyrotechnic pellet having an ignition temperature of at least 140°C, but below the violent ignition temperature of the propel lant material under slow cook-off condi tions, whereby the composite material of said casing loses its strength at the predetermined temperature, causing a casing failure and a non-propulsive burning of the rocket motor. The rocket motor ignition system, will be initiated when the ambient temperature of the rocket motor will be above 140°C, but below the self-ignition temperature of the propellant itself. The most preferred materials for the pyrotechnic pellets are selected from double-based propellants, such as: a mixture of nitroglycerine and nitrocellulose and additives, black powder, mixture of magnesium powder with teflon powder, boron barium chromate and any other known solid propellants which comply with the above requirement for the ignition temperature. Optionally, in order to improve the physical and chemical properties of the double-based propellants, small amounts of additives may be incorporated as stabilizers.
BRIEF DESCRIPTION OF THE FIGURES.
Figure 1, is a cross-section of a typical missile containing a rocket motor and a safe/arm ignition system.
Figure 2, is a cross-section of a typical safe/arm ignition system used to ignite a rocket motor containing a predetermined ignition temperature pyrotechnical pellet according to the present invention.
DETAILED DESCRIPTION OF THE FIGURES AND INVENTION ■ Figure 1 illustrates schematically a cross-section of a typical missile. The missile illustrated, includes a rocket motor (2), an explosive warhead (3) and a safe/arm ignition system (4) which is mounted coaxially in the rocket motor (2). The rocket motor (2) includes the casing (5), the nozzle (6) and the propellant material (7). A venting device (12) to avoid propulsive burning is provided, connecting the rocket motor casing (5) to the nozzle (6). The predetermined pyrotechnic pellet (11) is located in the safe ignition system (4).
In Figure 2, the safe/arm ignition system (4) includes a perforated plastic tube (8) which is threaded in a safe/ arm device (9). In the plastic tube (8) there are located igniter common pellets together with the predetermined ignition temperature pyrotechnical pellet which activates the igniter pellets.
The predetermined ignition temperature pyrotechnical pellet must be in the inner surface of the propellant grain, but its actual location therein is not critical. The arrangement tested in the slow cook-off oven, includes the rocket motor and the safe/arm ignition system mounted inside as illustrated in Figure 1. When the temperature in the slow cook-off oven reached the predetermined value, the predetermined pyrotechnical thermal pellet is ignited and activates the rocket motor igniter pellets. The hot gases and particles resulted from the ignition of said pellets, are going out through the holes of the perforated plastic tube (8) and thus will ignite the propel lant material (7). The predeterm ned pyrotech-nical ignition temperature thermal pellet located on the inner surfaces, will ignite the propellant grain.
When the casing of the rocket motor is made of a composite material which includes a resin and fibers, the resin is softened at a temperature of about 130°C. Thus, at a predetermined temperature which is above 130°C the resin will be significantly weakend. As a consequence, the casing will burst without causing any external effect and thus the propellant will burn non-propul s vel y at atmospheric pressure due to the full diameter opening of the case .
A detailed description and data of a typical safe/arm ignition system is hereafter presented, being understood, that this are given only for a better illustration of the invention, without limiting its scope as covered by the appending Claims. A person skilled in the art, after reading the present specification will be in a position to insert slight modif cations thereof without being outside the scope of the invention as stipulated in the attached Claims.
A typical illustration of a safe/arm ignition system is hereafter presented: -The internal length of the plastic tube about 77 mm. -The internal diameter of the tube about 8 mm.
-The tube does contain about 60 pellets (4.8X4.8 mm) of B-BaCr04 and also some pellets of a di-basic pyrotechnic material, with a diameter of about 7 mm and length of about 20 mm.
-The tube contains about 28 holes of 2 mm diameter divided in four rows.
Of course, the above data are given only for illustration purposes indicating some data and dimensions, but no limitation whatsoever could be understood therefrom.
Claims (9)
1. C L A I S :- 1. A device for imparting a non-explosive and a nonpropulsive property to a casing of a rocket motor made from a composite material during a slow cook-off test, said device comprising a predetermined pyrotechnic pellet having an ignition temperature of at least 140°C but below the violent ignition temperature of the propellant material under slow cook-off conditions, whereby the composite material of said casing loses its strength in the predetermined temperature, causing a casing failure and a non-propulsive burning of the rocket motor.
2. The device according to Claim 1, wherein the predetermined pyrotechnic pellet has an ignition temperature in the range of 140°C to 150°C.
3. The device according to Claim 1, wherein said predetermined pyrotechnic pellet is located in the inner surface of the propellant material. one o+ -the
4. The device according to. Claims 1 to 3, which includes Λ a perforated plastic tube threaded in a safe arm device.
5. The device according to Claim 4, wherein the perforated plastic tube contains common igniter pellets together with a predetermined temperature pyrotechni cal pellets. 108,819/3
6. The device according to Claims 1 to 5, wherein Λ said predetermined pyrotechnic pellets comprise double-based propel lants.
7. The device according to Claim 6, wherein said double-based propellants are selected from: mixtures of nitroglycerine, nitrocellulose and additives, black powder, mixtures of magnesium powder and teflon powder, and boron-barium chromate.
8. The device according to Claims 4, wherein hot gases and particles resulted from the ignition of said pellets are exhausted through the perforated plastic tube causing the ignition of the propellant material.
9. A device for imparting a non-explos ve and nonpropulsive property to a rocket motor casing made from a composite material during a slow cook-off test, substantially as described in the specification and in any one of Claims 1 to 8. For the Applicant, Simon Lavie Patent Attorney
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL10881994A IL108819A (en) | 1994-03-02 | 1994-03-02 | Rocket motor protection device during slow cook-off test |
| US08/370,810 US5813219A (en) | 1994-03-02 | 1995-01-10 | Rocket motor protection device during slow cook-off test |
| IL11532895A IL115328A (en) | 1994-03-02 | 1995-09-17 | Warhead protection device during slow cook-off test |
| GB9611151A GB2313653B (en) | 1994-03-02 | 1996-05-29 | Munition components protection device during slow cook-off test |
| US08/659,756 US5786544A (en) | 1994-03-02 | 1996-06-06 | Warhead protection device during slow cook-off test |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL10881994A IL108819A (en) | 1994-03-02 | 1994-03-02 | Rocket motor protection device during slow cook-off test |
| GB9611151A GB2313653B (en) | 1994-03-02 | 1996-05-29 | Munition components protection device during slow cook-off test |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IL108819A0 IL108819A0 (en) | 1995-07-31 |
| IL108819A true IL108819A (en) | 1996-12-05 |
Family
ID=26309407
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IL10881994A IL108819A (en) | 1994-03-02 | 1994-03-02 | Rocket motor protection device during slow cook-off test |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB2313653B (en) |
| IL (1) | IL108819A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2827376B1 (en) | 2001-07-13 | 2003-12-05 | Poudres & Explosifs Ste Nale | SAFETY IGNITER FOR PYROTECHNIC MUNITION ELEMENT LIKELY TO BE SUBJECTED TO SLOW HEATING |
| CN114837854B (en) * | 2022-04-19 | 2023-12-12 | 西安近代化学研究所 | Low-cost test device and method for simulating slow baking combustion of engine |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5129326A (en) * | 1987-04-14 | 1992-07-14 | Aerojet-General Corporation | Ordnance device with explosion protection |
| GB2214617A (en) * | 1988-01-25 | 1989-09-06 | Thiokol Morton Inc | Rocket motors and igniters |
| US5369955A (en) * | 1990-07-25 | 1994-12-06 | Thiokol Corporation | Gas generator and method for making same for hazard reducing venting in case of fire |
-
1994
- 1994-03-02 IL IL10881994A patent/IL108819A/en not_active IP Right Cessation
-
1996
- 1996-05-29 GB GB9611151A patent/GB2313653B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| GB2313653A (en) | 1997-12-03 |
| GB9611151D0 (en) | 1996-07-31 |
| GB2313653B (en) | 2000-12-20 |
| IL108819A0 (en) | 1995-07-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FF | Patent granted | ||
| KB | Patent renewed | ||
| KB | Patent renewed | ||
| KB | Patent renewed | ||
| MM9K | Patent not in force due to non-payment of renewal fees | ||
| MM9K | Patent not in force due to non-payment of renewal fees |