Explosive and thermic compositions or charges – Containing liquefied gaseous fuel or liquefied oxygen...
Reexamination Certificate
2000-02-22
2002-07-16
Carone, Michael J. (Department: 3641)
Explosive and thermic compositions or charges
Containing liquefied gaseous fuel or liquefied oxygen...
C149S045000, C149S108600, C060S211000, C060S212000
Reexamination Certificate
active
06419771
ABSTRACT:
MICROFICHE APPENDIX
Not Applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to a non-toxic hypergolic bipropellent and, more particularly, to a non-toxic bipropellent which contains a non-toxic hypergolic miscible fuel (hereinafter referred to as “NHMF”)and a rocket grade hydrogen peroxide oxidizer. The NHMF of this invention contains a polar organic species, a propagator, an inorganic metal salt, an alkali acetate and acetic acid.
2. Description of Related Art
Innovative propellants have long been used by the United States Navy for power generation, propulsion and ordnance. Prime considerations in the post World War II era have been specific impulse, volumetric energy content, surge/mobilization readiness and shipboard safety. While these parameters are still important, environmental concerns, commercial transitions and cost have been added to the list of considerations to be taken into account.
Traditional power generation systems include hydrazine monopropellant actuators, storable hypergolic thrusters using monomethyl hydrazine
itrogen tetroxide, and propulsion devices using halogen containing solid propellants. These systems all pose significant environmental problems and have high associated costs. Alternatively, traditional hypergolic bipropellants have been used, but have proved to be carcinogenic and toxic, as well as difficult and dangerous to manufacture.
In the past, hydrogen peroxide, as well as polar organic species such as alcohols have been used as components of bipropellants, mainly for rockets. However, inorganic contaminants in the hydrogen peroxide yielded an inadequate maximum upper concentration limit of hydrogen peroxide, which could be safely and effectively used in the bipropellant. Addition of hydrogen peroxide above these concentration limits created an unstable bipropellant system, both in usage and in storage.
When using traditional high strength hydrogen peroxides, long term containment, safe/practical enrichment and controlled catalytic decomposition problems have occurred. Hydrogen peroxide stored in non vented metallic containers posed a formidable problem, due to unplanned catalytic decomposition. In addition, traditional distillation technology yielded 90% hydrogen peroxide. Above 90%, the hydrogen peroxide vapors are detonable at the conditions of the distillation. Fractional crystallization is also a difficult separation technique due to water occlusion in hydrogen peroxide crystals. These technical problems were overcome by massive defense spending, which allowed for the use of extremely expensive and complex materials. However, with current decreased defense spending, low cost and life cycle waste generation become increasingly important factors in the development and manufacture of defense related products. The use of expensive and complex materials to overcome the above mentioned problems have now become impractical.
Researchers began evaluating alternative fuels for divert and attitude control systems (DACS) that would be shipboard compatible. Traditional hypergolic bipropellants usually involve hydrazine derivatives as the fuel and either inhibited red fuming nitric acid (IRFNA) or nitrogen tetroxide (NTO) as the oxidizer. As a result of these studies, a combination of concentrated hydrogen peroxide and JP-10, a jet fuel, derivative fuels as a potential DACS candidate. This concept and technology evolved over the years, and culminated with the development of a new class of hypergolic fuels.
A non-toxic hypergolic miscible bipropellant (NHMB) was developed to provide quickly renewable, hypergols which are non-toxic and form either solutions or true colloids. Please refer to U.S. Pat. No. 5,932,837 issued Aug. 3, 1999 to Rusek, et al. NHMB also provides a non-toxic hypergolic miscible fuel, which can be used in combination with a rocket grade hydrogen peroxide to form a safe, non-toxic miscible bipropellent with rapid ignition capabilities. In addition, NHMB provides a non-toxic hypergolic miscible fuel containing an inorganic metal salt, which reacts to form a catalyst in solution. This new bipropellant is especially applicable for use in divert/attitude control systems, orbit transfer systems, thrusters, large launch vehicle applications, as well as any motive power engines.
The concept of NHMF was derived from earlier research involving catalyst-doped JP fuels, specifically JP-10. These fuels were treated with a complex manganese organometallic compound and were not hypergolic with any concentration of rocket grade hydrogen peroxide (RGHP). The non-polarity of JP-10 and the polarity of RGHP did not lend itself to proper mixing of the two fuels, stifling chances of hypergolicity. In addition, theoretical energy calculations of the combination of the fuels and RGHP resulted in an optimum oxidizer to fuel ratio in the range 8-10. The next step was to find catalytically active manganese or other transition metal compound, which was soluble in a lower molecular weight, polar, flammable solvent.
Unfortunately, the NHMF of U.S. Pat. No. 5,932,837 was found to form a precipitate over time. The formation of the precipitate is accelerated by heat and by the presence of water. This raises a concern regarding the long term storability and subsequent performance of the NHMF in a propulsion system.
SUMMARY OF THE INVENTION
The present invention provides a non toxic bipropellent containing NHMF and rocket grade hydrogen peroxide oxidizer that resists the formation of precipitate over time when exposed to extreme heat. This is accomplished by buffering the pH of the NHMF in the origin of acidity with acetic acid and alkali acetate and the addition of a polar amide species to increase the polarity of the polar species of a lower alcohol. Increasing the polarity of the polar species keeps the solids soluble.
One object of the present invention to provide a NHMF which can be used in combination with a rocket grade hydrogen peroxide to form a safe, non toxic miscible bipropellent with rapid ignition capabilities and provide a NMHF, which remains stable when subjected to variations in temperature.
Another object of the invention is to provide a NHMF with improved storability.
A still further object of the invention is to provide a NHMF formulation, which minimizes or eliminates the formation of precipitate, especially when exposed to extreme heat.
The present invention provides a non toxic bipropellent containing a non toxic hypergolic miscible fuel (NHMF) and rocket grade hydrogen peroxide oxidizer. The non toxic hypergolic miscible fuel contains about 60 to 90 weight % polar organic species miscible with hydrogen peroxide, about 1.0- to 15 weight % propagator, about 5.0 to 23 weight % inorganic metal salts which react to form a catalyst in solution or as a colloid, about 1.0 to 10 weight % acetic acid, and about 1.0 to 10 weight % alkali acetate. The polar organic species can be C1 to C6 alcohols and/or C1 to C4 ketones, the propagator can be substituted or unsubstituted amides, amines and diamines, the inorganic metal salts is selected from the group consisting of manganese, copper, cobalt and iron, the acetic acid can be glacial acetic acid, and the alkali acetate can be potassium acetate, sodium acetate, and lithium acetate. Preferably, the hydrogen peroxide of the present invention consists of about 85 to 100 weight % hydrogen peroxide
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Not Applicable.
DETAILED DESCRIPTION OF THE INVENTION
Recently, with new analysis methods, it is possible to precisely determine types and quantities of contaminants present in the hydrogen peroxide. Knowing the types and quantities of contaminants present in the hydrogen peroxide, it is now possible to produce safer, higher concentration hydrogen peroxide for use in a bipropellent.
The NHMF of the present invention contains 5 species. Namely, a polar organic species or a mixture of polar organic species miscible with hydrogen peroxide; a propagator which is a basic organic species such as substituted or uns
Baker Aileen J.
Carone Michael J.
Serventi Anthony J.
The United States of America as represented by the Secretary of
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