Patent Application
20200325083
The present invention relates generally to ingredients or components for use in pyrotechnics, and more specifically, as a low-smoke alternative to black powder used in pyrotechnics.
Black powder has been used in pyrotechnic devices for thousands of years. It is an intimate mixture of approximately 75% potassium nitrate, 15% charcoal, and 10% sulfur. While its initial development was geared towards using it as an explosive weapon, its uses quickly expanded into the civil engineering and entertainment sectors. Its historic beginnings should be of no surprise, as there are many positive characteristics that make black powder an attractive composition for use in pyrotechnics. Firstly, black powder is readily ignitable due to the presence of sulfur and its low melting point. Secondly, black powder is made from components that are readily available and relatively inexpensive. Finally, black powder not only is able to propel or “lift” other pyrotechnic compositions effectively, it also forms a large amount of hot, solid particles during combustion which facilitate the ignition of secondary pyrotechnic compositions
There is a high demand for black powder replacements that provide acceptable burn rates upon combustion, generate high volumes of gas, and successfully initiate the combustion of and propel other pyrotechnic compositions. Black powder used in current pyrotechnic devices is undesirable for certain applications due to the fact that it typically produces substantial solid by-products from the composition's combustion in the form of smoke and other solid particulate matter. Current black powder replacements typically fail to reliably ignite secondary pyrotechnic compositions.
Accordingly, a need exists for gas generating compositions suitable for use in pyrotechnic applications that require similar gas-generating and heat transfer properties while also reducing smoke output.
The present invention is directed to a low-smoke, pyrotechnic composition that can be suitably used in applications where it is desirable to have minimal smoke production or other solid particulate matter production resulting from the combustion of the composition.
The low-smoke, pyrotechnic composition of the present invention includes Ceric Ammonium Nitrate (CAN) (chemical formula: H8N8CeO18) as an oxidizing agent in order to limit the production of solid by-product, including smoke generation, during combustion of the composition. The Ceric Ammonium Nitrate within the low-smoke, pyrotechnic composition generates large amounts of oxygen useful in propagating combustion and generates nitrogen gas useful in propulsion, while also providing noticeably reduced smoke and particulate matter generation during combustion as compared to other common oxidizers.
According to one embodiment of the present invention, the low-smoke, pyrotechnic composition can include a fuel source, a stabilizer, a binder, and Ceric Ammonium Nitrate as an oxidizer. In certain embodiments, the composition may include additional oxidizing agents in addition to Ceric Ammonium Nitrate; however, Ceric Ammonium Nitrate must be present in the composition of the present invention. The low-smoke, pyrotechnic composition in accordance with the various embodiments of the present invention may include any suitable fuel source or fuel sources, including without limitation, metal and non-metal fuel sources, any suitable type of stabilizing agent or agents, and any suitable type of binding agent or agents.
According to one embodiment of the present invention, the low-smoke, pyrotechnic composition can include 20-80 percent by weight Ceric Ammonium Nitrate, 5-60 percent by weight the fuel source(s), 1-20 percent by weight the stabilizer(s), and 0-15 percent by weight the binder(s).
The low-smoke, pyrotechnic composition may also include a burn rate catalyst in accordance with one or more embodiments. The burn rate catalyst may include any suitable type or types of burn rate catalysts or heat generating compounds. The selection of the particular burn rate catalyst or heat generating compound, or a combination thereof, may be selected based at least in part on the desired effect and particular pyrotechnic application.
According to one embodiment of the present invention, the low-smoke, pyrotechnic composition can include Ceric Ammonium Nitrate as an oxidizer, Nitrocellulose as a non-metal fuel source, Titanium as a metal fuel source, Cyanoguanidine as a stabilizer, Cupric Oxide as a burn rate catalyst, and any suitable binder compound. In additional embodiments, one or more fuel sources, stabilizers, burn rate catalysts and/or oxidizers may be added to the low-smoke, pyrotechnic composition depending on the particular application.
According to a specific embodiment of the present invention, the low-smoke, pyrotechnic composition can include approximately 30-40% by weight Ceric Ammonium Nitrate (oxidizer), approximately 45-55% by weight Nitrocellulose (non-metal fuel source), approximately 0.1-3.0% by weight Cyanoguanidine (stabilizer), approximately 5-10% Cupric Oxide (burn rate catalyst), and approximately 0-15% of a suitable binder material.
According to a specific embodiment, the low-smoke, pyrotechnic composition can include approximately 36.7% by weight of Ceric Ammonium Nitrate (˜50 um), approximately 51.4% by weight of Nitrocellulose, approximately 3.7% by weight Titanium (˜325 mesh), approximately 0.9% by weight Cyanoguanidine, approximately 7.3% by weight of Cupric Oxide, and approximately 0-15% by weight of a binder material.
Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.
The following detailed description of the invention references specific embodiments in which the invention can be practiced. The embodiments are intended to describe aspects of the invention in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments can be utilized and changes can be made without departing from the scope of the present invention. The present invention is defined by the appended claims and the description is, therefore, not to be taken in a limiting sense and shall not limit the scope of equivalents to which such claims are entitled.
The present invention is directed to a low-smoke, pyrotechnic composition that can be used in pyrotechnic applications where it is desirable to have a minimal amount of smoke or other solid particulate matter produced as a result of combustion of the composition. The low-smoke, pyrotechnic composition of the present invention can be utilized in connection illuminating pyrotechnic compositions and/or propellant compositions depending on the desired application. For example, the low-smoke, pyrotechnic composition of the present invention may be utilized to create an illuminating light, flash or flame, heat and/or sound in connection with the combustion of the composition while limiting the overall production of smoke generated in connection with the chemical reaction and combustion.
The principal component in the low-smoke, pyrotechnic composition of the present invention is Ceric Ammonium Nitrate, which is used as an oxidizer. Ceric Ammonium Nitrate is an inorganic compound with the formula (NH4)2Ce(NO3)6 (chemical formula: H8N8CeO18) and is often used as an oxidant in organic synthesis. Ceric Ammonium Nitrate (CAN) can also be referred to as Diammonium cerium hexanitrate, Diammonium hexanitratocerate(2-), and Ammonium cerium nitrate (VAN). CAN is used as the main oxidizing agent in the low-smoke, pyrotechnic composition and limits the production of solid by-product, including smoke generation during combustion of the composition.
Ceric Ammonium Nitrate is necessary in the low-smoke, pyrotechnic composition of the present invention, as it generates large amounts of oxygen useful in propagating combustion, and nitrogen gas useful in propulsion; it is also readily ignitable in the presence of organic fuels. CAN has likely found limited use in the pyrotechnics industry due to availability issues as well as its ready ability to oxidize various materials at room temperature when solvated.
Decomposition of one gram of Ceric Ammonium Nitrate generates 0.53 grams of oxygen, 0.2 grams of nitrogen, and 0.1 grams of hydrogen. The mass of oxygen generated is comparable with other common oxidizers such as potassium nitrate (0.40 grams of oxygen/gram), potassium chlorate (0.39 grams of oxygen/gram), and potassium perchlorate (0.46 grams of oxygen/gram). The combustion of CAN forms 0.31 grams of Cerium (IV) Oxide and 0.13 grams of water vapor. After subtracting the oxygen that falls out as Cerium (IV) Oxide and water vapor, 0.35 grams of free oxygen are left to participate in the combustion process. Using this information, it is found that over 69% of the byproducts of the decomposition of CAN are gaseous, and the combustion of formulations using CAN as an oxidizer have noticeably reduced smoke generation.
Ceric Ammonium Nitrate is also advantageous in the low-smoke, pyrotechnic composition of the present invention due to its low melting point. Sulfur's implementation as a low-melting point fuel in black powder has a drawback in that its presence leads to large amounts of solid sulfide byproducts that increases the smoke output of the composition. CAN's low melting point and high ignitability with organic fuels greatly reduces the amount of activation energy necessary for combustion and eliminates the need for sulfur. Furthermore, Ceric Ammonium Nitrate and its byproducts are environmentally benign.
As illustrated in Table I below, according to one embodiment, the low-smoke, pyrotechnic composition of the present invention can include a fuel source, a stabilizer, a binder, and Ceric Ammonium Nitrate as an oxidizer. In certain embodiments, additional oxidizers may be utilized with the Ceric Ammonium Nitrate; however, Ceric Ammonium Nitrate is the only specific component of the composition that cannot be removed or replaced. Additional oxidizers that may be used in conjunction with the Ceric Ammonium Nitrate may include, but are not limited to, nitrate salts, perchlorate salts, and metal oxides. In certain embodiments, the low-smoke pyrotechnic composition of the present invention can include one or more of each type of component comprising the composition. In such embodiments, the low-smoke, pyrotechnic composition can include at least one fuel source agent, at least one stabilizer agent, at least one binder agent, and at least one oxidizer agent including at least Ceric Ammonium Nitrate.
The fuel can be metal or non-metal source and the composition can include multiple fuel sources in certain embodiments. Non-limiting examples of suitable fuel sources that may be used in the low-smoke, pyrotechnic composition of the present invention can include: Nitrocellulose, Hexamine, Nitroguanidine, Red Gum, Titanium, Aluminum, Magnesium, Boron, Charcoal, Silicon, any transition metals or other types of fuel source now known or hereinafter developed or commonly used in the art.
The stabilizer can be any suitable stabilizing agent, including without limitation: Cyanoguanidine, Dicyanodiamide, 2-cyanoguanidine, Guanidine-1-carbonitrile, Diphenylamine, Nitrodiphenylamine, Akardite, Ethyl Centralite, Methyl Centralite, Carbonate salts, or other type of stabilizer now known or hereinafter developed or commonly used in the art.
The binder can be a suitable compound or substance that can bind/bond the other components of the low-smoke, pyrotechnic composition. Non-limiting examples of a suitable binder that may be used in the low-smoke gas-generating composition of the present invention can include: Ethylcellulose, Methylcellulose, Hydroxypropyl methylcellulose, Hydroxypropyl ethylcellulose polyvinyl alcohol, Viton, Parlon, polyvinyl pyrrolidone, polyethylene glycol, polyethylene glycol-polyvinyl alcohol copolymer, epoxy resins and their appropriate, crosslinking compounds, or other binder agents now known or hereinafter developed or commonly used in the art.
As illustrated in Table II below, the low-smoke gas generating composition of the present invention can also include at least one burn rate catalyst or heat generating compound or compounds depending on the desired effect and particular pyrotechnic application. According to one embodiment, the low-smoke, pyrotechnic composition of the present invention can include Cupric Oxide as a burn rate catalyst. Other potentially suitable catalysts can include, but are not limited to, Ferric Oxide, Titanium Dioxide, Bismuth Trioxide, Molybdenum Trioxide, barium peroxide, strontium peroxide, calcium peroxide, chromic oxide, silicon dioxide, manganese (II) oxide, boron oxide or other desired compounds commonly used in the art.
As illustrated in Table III below, according to one preferred embodiment of the present invention, the low-smoke, pyrotechnic composition includes Ceric Ammonium Nitrate as an oxidizer, Nitrocellulose as a non-metal fuel source, Titanium as a metal fuel source, Cyanoguanidine as a stabilizer, Cupric Oxide as a burn rate catalyst, and any suitable binder compound. The table below illustrates this preferred formula for low-smoke, pyrotechnic composition. As shown the Ceric Ammonium Nitrate can have a suitable range of 20-80 percent by weight of the overall formula. In addition, the other components of the composition can vary substantially by percent by weight and can be replaced with other suitable compounds depending on the particular application.
According to one preferred embodiment of the present invention, the low-smoke, pyrotechnic composition includes approximately 36.7% by weight of Ceric Ammonium Nitrate (˜50 um), approximately 51.4% by weight of Nitrocellulose, approximately 3.7% by weight Titanium (˜325 mesh), approximately 0.9% by weight Cyanoguanidine, approximately 7.3% by weight of Cupric Oxide, and approximately 0-15% by weight of a binder material. The specific % by weights may vary depending on the particular or desired application and or the amount of binder material utilized. For example, the particular amount by weight of Ceric Ammonium Nitrate as an oxidizer may range between 36.0-37.5% according to certain embodiments or may range between 30-40% in other embodiments. Table IV below illustrates one specific embodiment of the low-smoke, pyrotechnic composition along with potential ranges (by percent weight) of each ingredient or compound included in the composition.
The low-smoke, pyrotechnic composition of the present invention, as described, herein results in minimal solid particulate and smoke by-product production during the combustion of the composition while still providing the desired burn temperatures, burn rates and other desired effects for various pyrotechnic applications. The Ceric Ammonium Nitrate is the key ingredient in the composition of the present invention that produces comparable performance characteristics to that of black powder while reducing or eliminating its negative attributes. In particular the inclusion of Ceric Ammonium Nitrate in the low-smoke, pyrotechnic composition of the present invention in accordance with the percent by weight ranges as described herein has the effect of producing limited smoke generating during combustion of the composition when compared to traditional pyrotechnic compositions.
For safety and longevity reasons, the compositions must be stabilized through the use of hydrophobic binders such as epoxy resin, viton, or polyvinyl butyral. Any number of suitable manufacturing and production methods can be utilized in the preparation of the low-smoke pyrotechnic composition of the present invention depending on the particular embodiment, including without limitation, manufacturing and production methods currently used in the pyrotechnics industry or hereinafter developed, or any other methods or techniques used in the production of chemical compositions. The low-smoke pyrotechnic composition of the present invention has several potential benefits, including without limitation, tunable performance aspects through minimal formulation changes, and the generation of mostly gaseous byproducts which increases performance while lowering the smoke output.
From the foregoing, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure. It will be understood that certain features and sub combinations are of utility and may be employed without reference to other features and sub combinations. This is contemplated by and is within the scope of the claims.
The constructions described above are presented by way of example only and are not intended to limit the concepts and principles of the present invention. Thus, there has been shown and described several embodiments of a novel invention. As is evident from the foregoing description, certain aspects of the present invention are not limited by the particular details of the examples illustrated herein, and it is therefore contemplated that other modifications and applications, or equivalents thereof, will occur to those skilled in the art. The terms “having” and “including” and similar terms as used in the foregoing specification are used in the sense of “optional” or “may include” and not as “required”. Many changes, modifications, variations and other uses and applications of the present construction will, however, become apparent to those skilled in the art after considering the specification. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.
This application claims priority to U.S. Provisional Patent Application Ser. No. 62/832,003, filed on Apr. 10, 2019, to Lyle Salmi et al., entitled “Low-Smoke Pyrotechnic Composition,” currently pending, the entire disclosure of which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62832003 | Apr 2019 | US |
