EP0579781A1 - Compositions de propulseurs a azotures utilisees pour le deballastage d'urgence de vaisseaux submersibles - Google Patents

Compositions de propulseurs a azotures utilisees pour le deballastage d'urgence de vaisseaux submersibles

Info

Publication number
EP0579781A1
EP0579781A1 EP92917352A EP92917352A EP0579781A1 EP 0579781 A1 EP0579781 A1 EP 0579781A1 EP 92917352 A EP92917352 A EP 92917352A EP 92917352 A EP92917352 A EP 92917352A EP 0579781 A1 EP0579781 A1 EP 0579781A1
Authority
EP
European Patent Office
Prior art keywords
composition
azide
nitrate
alkali metal
lithium
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.)
Withdrawn
Application number
EP92917352A
Other languages
German (de)
English (en)
Other versions
EP0579781A4 (fr
Inventor
John F. Pietz
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Talley Defense Systems Inc
Original Assignee
Talley Defense Systems Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Talley Defense Systems Inc filed Critical Talley Defense Systems Inc
Publication of EP0579781A1 publication Critical patent/EP0579781A1/fr
Publication of EP0579781A4 publication Critical patent/EP0579781A4/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63G—OFFENSIVE OR DEFENSIVE ARRANGEMENTS ON VESSELS; MINE-LAYING; MINE-SWEEPING; SUBMARINES; AIRCRAFT CARRIERS
    • B63G8/00—Underwater vessels, e.g. submarines; Equipment specially adapted therefor
    • B63G8/14—Control of attitude or depth
    • B63G8/24—Automatic depth adjustment; Safety equipment for increasing buoyancy, e.g. detachable ballast, floating bodies
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
    • C06B35/00—Compositions containing a metal azide
    • C—CHEMISTRY; METALLURGY
    • C06—EXPLOSIVES; MATCHES
    • C06D—MEANS FOR GENERATING SMOKE OR MIST; GAS-ATTACK COMPOSITIONS; GENERATION OF GAS FOR BLASTING OR PROPULSION (CHEMICAL PART)
    • C06D5/00—Generation of pressure gas, e.g. for blasting cartridges, starting cartridges, rockets

Definitions

  • the invention relates to solid pyrotechnic propellant compositions for emergency deballasting of submersible vessels and more particularly, to blends of alkali metal azides and alkali metal nitrates for use therein.
  • a submersible vessel i.e., a submarine, propels itself from its operating depth to the ocean surface in a manner similar to that of an airplane taking off. Adjustable bow and stern planes, which fold out of the way when not needed, permit the vessel to change its depth as required.
  • the vessel maintains its buoyancy by expelling sea water from its trim tanks with the use of compressed air. This is a relatively simple matter since the only pressure which must be overcome in evacuating water from the trim tanks on the surface is the ambient pressure of the atmospher .
  • SUBSTITUTE SHEET systems store a large volume of high pressure (i.e., 4500 psi) air for this purpose. This air is carried by large diameter piping to the main ballast tanks for use in surfacing the vessel under emergency conditions such as those described herein. Although a compressed air system is easily maintained and replenished, it suffers, however, from several important drawbacks as described below.
  • One drawback to the use of a compressed air system is that the thick-walled pressure vessels and distribution piping required to store and transport the high pressure air are bulky and heavy. The estimated total weight of such a system is in excess of 100 tons, with the total volume of the system exceeding 1,000 cubic feet.
  • Gas generators are typically classified as either solid or liquid fueled, as discussed below in turn.
  • solid fueled gas generator whose use in submarine deballasting systems has previously been investigated relies upon rapid, controlled combustion (i.e., deflagration) of a solid fuel mixture to produce large quantities of pressurized gasses.
  • This device is essentially a slow-burning rocket engine designed to produce pressure rather than thrust.
  • Propellants typically utilized with such generators include heterogeneous composites containing a finely divided oxidizer dispersed in a hydrocarbon fuel/binder. The burning rate of these propellants is determined primarily by the chemical composition of the propellant and the exhaust pressure against which it is operating.
  • inorganic azide-based propellants which have been developed for the automobile airbag industry. These materials produce substantially pure nitrogen by the thermal decomposition of sodium azide into metallic oxides and free metals.
  • the combination of stoichiometric amounts of an alkali azide and a metal oxide or an alkali nitrate is known to yield a relatively efficient nitrogen-producing mixture for use in such passive restraints.
  • propellants form a substantial amount of undesirable solid particulates along with the gas. For instance, blending stoichiometric levels of sodium azide and sodium nitrate yields a propellant which, upon deflagration, produces combustion products comprising 55% by weight of nitrogen and 45% by weight of solids.
  • a second type of solid fueled gas generator produces gas by the rapid oxidation of alkali metals.
  • metallic sodium, lithium and their hydrides react vigorously with water to produce substantial quantities of gaseous products.
  • These products comprise metallic hydroxides and high levels of gaseous hydrogen which, as noted above, can form explosive mixtures when mixed in certain proportions with air.
  • liquid propellants for gas generators are classed as either bipropellant combinations or monopropellants.
  • Bipropellants comprise separate fuel and oxidizer sources which are vaporized either through a hyperbolic, i.e., spontaneously igniting, reaction or by the addition of heat.
  • bipropellant engines are widely used in missile applications, their complexity, high reaction temperatures and poor performance when operated non- stoichiometrically weigh heavily against their use as gas generators for use in submersible vessels.
  • Monopropellants contain both the fuel and oxidizer in a single system. They are, in contrast to the bipropellants, relatively simple and operate at substantially lower reaction temperatures than the bipropellant systems.
  • Hydrazine is one monopropellant utilized in several navies for submarine emergency deballasting systems. Hydrazine decomposes spontaneously in an exothermic reaction to form ammonia and nitrogen. Further decomposition of the ammonia in an endothermic reaction on a catalyst bed produces hydrogen and nitrogen in approximately a 2:1 ratio. Formation of
  • compositions for use in submarine emergency deballasting applications.
  • these compositions comprise various blends of alkali metal azide and alkali metal nitrate
  • the azide and nitrate components of the propellant blends 5 are combined in approximately stoichiometric proportions as known in the art.
  • SUBSTITUTESHEET are, however, modified by the addition of a mixture of an inert silicon-containing compound, such as silicon dioxide, and a metal oxide whose metal component has a melting point such that the metal remains substantially solid at the deflagration temperature of the propellant.
  • the amount of these two materials is specifically chosen to substantially prevent the formation of particulate combustion products in the propellant gas. This occurs by forming a solid slag or clinker which remains within the gas generator and thus captures the particulates so as to prevent them from entering the ballast tanks.
  • Use of such blends of the type described above, chosen to form the solid clinker and thus prevent the escape of particulates from the generator, provides a substantially improved performance over other materials relied upon for this purpose in the prior art.
  • the present invention is directed to solid propellant compositions for use in emergency deballasting systems for submersible vessels.
  • These compositions comprise, in a first embodiment, non- stoichiometric blends of an alkali metal azide and an alkali metal nitrate.
  • alkali metals listed in Group IA of the Periodic Table sodium and potassium are presently contemplated for use in the invention on the basis of their cost, availability and relatively low atomic weight, i.e., compared to that of rubidium, cesium and franciu , some of the remaining alkali metals.
  • Lithium which has even a lower atomic weight than that of either sodium or potassium, is correspondingly even more useful in the invention. At the present time, however, lithium-based compounds are
  • blends of alkali metal azides and alkali metal nitrates - in stoichiometric ratios - are known for a variety of applications. What has not been previously disclosed, however, or previously practiced, is the combination of these materials in non-stoichiometric blends since, as noted above, a reduction in the amount of the oxidizing component, i.e., the alkali nitrate, results in the formation of combustion products comprising nitrogen gas and molten bits of the alkali metal chosen for use. Exhausting these particulates into a ballast tank at least partially filled with sea water thus results in the formation of hydrogen gas in addition to the nitrogen gas which is already present. The amount of hydrogen generated is limited, however, to about 13-14% by volume so as to prevent the formation of an explosive mixture when combined with air.
  • the level of hydrogen gas thus produced by the deflagration of this material can be maintained at _ 0 below about 13% by volume, i.e., an amount which is not explosive when mixed with air.
  • Tables I-III below set forth the relative amount of hydrogen gas (remainder nitrogen gas) achieved with *L5 the use of various ratios of alkali metal azides to their corresponding alkali metal nitrates.
  • the blends disclosed in Tables I-III are capable of numerous variations.
  • the alkali o metals used to form the azide and the nitrate need not be the same in both cases as shown in the charts but rather, they can be mixed and matched within the broad category of the Group 1A metals of the Periodic Table (e.g., sodium azide with potassium nitrate).
  • the 5 information in these tables is provided for the purpose of illustration only and is not intended to limit the invention to the specific compositions or ratios described.
  • the first line of each table represents a stoichiometric mixture of the particular azide and nitrate shown. 5
  • the present invention is thus intended to include propellant compositions comprised of an alkali metal azide and an alkali metal nitrate wherein the ratio of the azide to the nitrate ranges from just above stoichiometric, i.e., wherein a minimal amount of hydrogen gas is produced, to a value that will result in the formation of no more than about 12.5% by volume of hydrogen in the combustion gas since, as noted above, at exhaust gas concentrations of about 13%-14% by volume and above, hydrogen tends to form an explosive mixture when mixed with air.
  • SUBSTITUTE SHEET SUBSTITUTE SHEET These values will necessarily vary depending upon the particular azide/nitrate combination used. For instance, with a blend of sodium azide and sodium nitrate as set forth in Table I, the amount of sodium azide utilized preferably ranges between about 79.5 and 87.3 wt. % with a sufficient amount of the nitrate present to total 100% by wt. For blends of potassium azide and potassium nitrate (Table II) , the corresponding percentage range of KN 3 from about 80.2 to 87.8 wt. %. For lithium azide and lithium nitrate (Table III) , this preferable range is about 78.2 to about 86.5 wt. %.
  • the composition represented by the last line i.e., 87.3% NaN 3 and 12.7% NaN0 3 , produces 22% more gas
  • the subject embodiment comprises, as described above, blends of alkali metal azides and nitrates, which in this instance are blended in approximately stoichiometric ratios. As discussed above, such blends produce a substantial amount of particulate combustion products upon deflagration. These products at least partially include small liquid particles of the alkali metal oxide(s) which comprise the
  • SUBSTITUTE SHEET propellant Upon contact with sea water in the ballast tanks, caustic hydroxides such as sodium hydroxide (NaOH) , potassium hydroxide (KOH) and lithium hydroxide (LiOH) (depending upon which alkali metals are present) , are formed. These caustic solutions may cause damage to some ballast tank components over time.
  • CaOH sodium hydroxide
  • KOH potassium hydroxide
  • LiOH lithium hydroxide
  • ferric oxide is the preferred metal oxide for use in the invention
  • any metal oxide such as the oxides of titanium, nickel, vanadium, manganese, chromium and cobalt, may be used wherein the metal component of the oxide has a sufficiently high melting point such that the compound remains substantially solid at the reaction temperature at which deflagration takes place.
  • the preferred amount of metal oxide may vary depending upon which oxide is used but will preferably range between about 5 and 18% by weight.
  • Table IV set forth below illustrates the results obtained by using either silicon dioxide or iron oxide to form the clinker, as compared to the combination of these two materials. Moreover, although the percentage of solids is provided only for the sodium-containing salts
  • the deballasting gas must be: - non-explosive (when mixed with air) , non-toxic (when personnel may be exposed) , and non-corrosive to the ballast tank structure and piping; the heat introduced into the ballast tank must not cause the temperature of the pressure hull to rise more than 100°F, nor that of the ballast tank structure to rise more than 600°F; and the gas generant fuel must be - safe to handle, transport and store, non-toxic (if stored within the pressure hull) and reliable after 20 years of storage.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Combustion & Propulsion (AREA)
  • Air Bags (AREA)

Abstract

Dans des conditions d'urgence telles qu'une perte de contrôle des moyens de propulsion, on peut déballaster un submersible au moyen d'une pluralité de générateurs solides de gaz combustibles comportant chacun une composition de propulseur comprenant un mélange d'un azoture de métal alcalin et d'un nitrate de métal alcalin, dans lequel le rapport de l'azoture et du nitrate se situe depuis un niveau supérieur au rapport stoechiométrique jusqu'à une quantité ne produisant pas plus de 13-14 % en volume d'hydrogène dans le gaz de déballastage à la déflagration du propulseur. Dans un autre mode de réalisation, un propulseur de déballastage ne produisant pas d'hydrogène gazeux comprend un mélange sensiblement stoechiométrique d'un azoture de métal alcalin et d'un nitrate de métal alcalin, combiné avec un additif constitué par une matière inerte contenant du silicium, tel que du dioxyde de silicium, et un oxyde de métal, dans lequel le constituant métallique de l'oxyde fond à une température suffisamment élevée pour rester pratiquement solide pendant la déflagration du propulseur. Ladditif sert à lier les particules fondues produites par la déflagration du propulseur, en scories solides et, de ce fait, à empêcher cette matière de passer dans les réservoirs de ballast.
EP19920917352 1991-04-11 1992-04-10 Compositions de propulseurs a azotures utilisees pour le deballastage d'urgence de vaisseaux submersibles. Withdrawn EP0579781A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US68392691A 1991-04-11 1991-04-11
US683926 1991-04-11
PCT/US1992/002978 WO1992018443A1 (fr) 1991-04-11 1992-04-10 Compositions de propulseurs a azotures utilisees pour le deballastage d'urgence de vaisseaux submersibles

Publications (2)

Publication Number Publication Date
EP0579781A1 true EP0579781A1 (fr) 1994-01-26
EP0579781A4 EP0579781A4 (fr) 1994-12-07

Family

ID=24746033

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19920917352 Withdrawn EP0579781A4 (fr) 1991-04-11 1992-04-10 Compositions de propulseurs a azotures utilisees pour le deballastage d'urgence de vaisseaux submersibles.

Country Status (3)

Country Link
EP (1) EP0579781A4 (fr)
JP (1) JPH06506663A (fr)
WO (1) WO1992018443A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2800875B2 (ja) * 1993-01-21 1998-09-21 ティーアールダブリュー・インコーポレーテッド 車両搭乗者衝撃抑制具のためのガス発生器
IL181423A0 (en) * 2007-02-19 2008-01-06 Waldhorn Joshua Apparatus and method for improving movement of floating or under water marine vessels
KR100899110B1 (ko) * 2007-10-22 2009-05-25 경희대학교 산학협력단 아지드화물 기폭제를 이용한 안전주입탱크 장치
IT201700065613A1 (it) * 2017-06-13 2018-12-13 Tech For Propulsion And Innovation S R L Gruppo o sistema per l'emersione rapida di sommergibili o di sottomarini.

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2981616A (en) * 1956-10-01 1961-04-25 North American Aviation Inc Gas generator grain
FR1571501A (fr) * 1968-05-07 1969-06-20
FR1593369A (fr) * 1968-11-26 1970-05-25
FR1598530A (fr) * 1968-12-19 1970-07-06
DE2217780A1 (de) * 1972-04-13 1973-10-25 Battelle Institut E V Verfahren zur foerderung von fliessfaehigen materialien
FR2193801A1 (fr) * 1972-07-24 1974-02-22 Canadian Ind
US3947300A (en) * 1972-07-24 1976-03-30 Bayern-Chemie Fuel for generation of nontoxic propellant gases
US4931111A (en) * 1989-11-06 1990-06-05 Automotive Systems Laboratory, Inc. Azide gas generating composition for inflatable devices

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3920575A (en) * 1973-03-03 1975-11-18 Asahi Chemical Ind Gas generating composition and method of preparing compression molded articles therefrom
GB1520497A (en) * 1975-04-23 1978-08-09 Daicel Ltd Gas-generating agent for air bag
US4547235A (en) * 1984-06-14 1985-10-15 Morton Thiokol, Inc. Gas generant for air bag inflators
JPH0737357B2 (ja) * 1987-03-10 1995-04-26 日本工機株式会社 ガス発生剤組成物
US4836255A (en) * 1988-02-19 1989-06-06 Morton Thiokol, Inc. Azide gas generant formulations
DE3842838C1 (fr) * 1988-12-20 1990-01-11 Dynamit Nobel Ag, 5210 Troisdorf, De

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2981616A (en) * 1956-10-01 1961-04-25 North American Aviation Inc Gas generator grain
FR1571501A (fr) * 1968-05-07 1969-06-20
FR1593369A (fr) * 1968-11-26 1970-05-25
FR1598530A (fr) * 1968-12-19 1970-07-06
DE2217780A1 (de) * 1972-04-13 1973-10-25 Battelle Institut E V Verfahren zur foerderung von fliessfaehigen materialien
FR2193801A1 (fr) * 1972-07-24 1974-02-22 Canadian Ind
US3947300A (en) * 1972-07-24 1976-03-30 Bayern-Chemie Fuel for generation of nontoxic propellant gases
US4931111A (en) * 1989-11-06 1990-06-05 Automotive Systems Laboratory, Inc. Azide gas generating composition for inflatable devices

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO9218443A1 *

Also Published As

Publication number Publication date
WO1992018443A1 (fr) 1992-10-29
EP0579781A4 (fr) 1994-12-07
JPH06506663A (ja) 1994-07-28

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