MULTICOLOR STROBING PYROTECHNIC FLARE

Abstract

A multicolor strobing pyrotechnic flare including a plurality of alternating pyrotechnic layers. The plurality of alternating pyrotechnic layers includes n pyrotechnic layers and the n pyrotechnic layers include m different pyrotechnic layer types, n is 2 to 2,000 and m is 2 to 2,000. The n pyrotechnic layers include a first pyrotechnic layer and a second pyrotechnic layer and the first pyrotechnic layer includes a first pyrotechnic compound and the second pyrotechnic layer includes a second pyrotechnic compound. Burning of the first pyrotechnic compound emits a first color and burning of the second pyrotechnic compound emits a second color and the first color and the second color are different.

Claims

1. A multicolor strobing pyrotechnic flare comprising a plurality of alternating pyrotechnic layers, wherein the plurality of alternating pyrotechnic layers comprises n pyrotechnic layers and the n pyrotechnic layers comprise m different pyrotechnic layer types, wherein n is 2 to 2,000 and m is 2 to 2,000, wherein the n pyrotechnic layers comprise a first pyrotechnic layer and a second pyrotechnic layer, wherein the first pyrotechnic layer comprises a first pyrotechnic compound and the second pyrotechnic layer comprises a second pyrotechnic compound, wherein burning of the first pyrotechnic compound emits a first color and burning of the second pyrotechnic compound emits a second color and the first color and the second color are different.

2. The flare of claim 1, wherein the flare comprises a stack of the plurality of alternating pyrotechnic layers.

3. The flare of claim 1, wherein the plurality of alternating pyrotechnic layers comprises a third propellent layer, wherein the third pyrotechnic layer comprises a fourth pyrotechnic compound and the fourth pyrotechnic compound emits a fourth color when burning and the fourth color is different than the first color and the second color.

4. The flare of claim 2, wherein the alternating pyrotechnic layers are provided in a repeating pattern wherein the second pyrotechnic layer is disposed between the first pyrotechnic layer and the third pyrotechnic layer in a repeating pattern of first pyrotechnic layer/second pyrotechnic layer/third pyrotechnic layer.

5. The flare of claim 1, wherein burning of the pyrotechnic layers emits a color with a wavelength of 380 to 450 nanometers, 450 to 495 nanometers, 495 to 570 nanometers, 570 to 590 nanometers, 590 to 620 nanometers, 620 to 750 nanometers, or a combination thereof.

6. The flare of claim 1, wherein each of the alternating pyrotechnic layers comprise a pyrotechnic compound comprising an organic fuel, a metal salt, or a combination thereof.

7. The flare of claim 1, wherein the first pyrotechnic compound has a first burn rate and the second pyrotechnic compound has a second burn rate and the first burn rate and the second burn rate are different.

8. The flare of claim 1, wherein the first pyrotechnic layer comprises the first pyrotechnic compound and a third pyrotechnic compound, wherein the third pyrotechnic compound has a third burn rate and the first burn rate and the third burn rate are different.

9. The flare of claim 1, wherein the thickness of the first pyrotechnic layer and the second pyrotechnic layer are different or the same.

10. The flare of claim 1, wherein the flare is in a linear stack configuration or a spherical stack configuration.

11. The flare of claim 1, wherein a delay material is interposed between each of the alternating pyrotechnic layers.

12. The flare of claim 10, wherein the delay layers burn with an illuminance of less than 0.05 lux.

13. The flare of claim 10, wherein the delay material comprises an organic fuel.

14. A method of providing a pyrotechnic effect comprising providing a multicolor strobing pyrotechnic flare comprising a plurality of alternating pyrotechnic layers, wherein the plurality of alternating pyrotechnic layers comprises n pyrotechnic layers comprising m different pyrotechnic layer types, wherein n is 2 to 2,000 and m is 2 to 2,000; igniting a surface of the flare, wherein igniting the surface of the flare sequentially burns a first pyrotechnic layer of the n pyrotechnic layers and a second pyrotechnic layer of the n pyrotechnic layers, wherein as the first pyrotechnic layer burns the first pyrotechnic layer emits a first color and as the second pyrotechnic layer burns the second pyrotechnic layer emits a second color, wherein the first color and the second color are different.

15. The method of claim 14, wherein burning of the m different pyrotechnic layer types emits m different colors.

16. A method of manufacturing a multicolor strobing pyrotechnic flare, wherein the plurality of alternating pyrotechnic layers comprises n pyrotechnic layers comprising m different pyrotechnic layer types, wherein n is 2 to 2,000 and m is 2 to 2,000.

17. The method of claim 16, wherein the plurality of pyrotechnic layers is assembled layer by layer by additive manufacturing; by pressing a first pyrotechnic layer of the n pyrotechnic layers on a second pyrotechnic layer of the n pyrotechnic layers under pressure and pressing a second layer of the first pyrotechnic layer on the opposing surface of the second pyrotechnic layer and repeating the stacking and pressing process until a desired quantity of stacked pyrotechnic layers are attained; or by dispersing n1 pyrotechnic layers in the first pyrotechnic layer.

18. The method of claim 16, wherein the plurality of pyrotechnic layers are assembled in a stack by an alternating coating process comprising: coating a first layer of a first pyrotechnic layer of the n pyrotechnic layers with a second pyrotechnic layer of the n pyrotechnic layers, coating an opposing surface of the second pyrotechnic layer with a second layer of the first pyrotechnic layer, and repeating the alternating coating process until a desired quantity of stacked pyrotechnic layers are obtained.

19. The method of claim 16, wherein a delay layer is interposed between each of the alternating pyrotechnic layers.

20. The method of claim 16, wherein a first pyrotechnic layer of the n pyrotechnic layers comprises a first pyrotechnic compound and a second pyrotechnic layer n pyrotechnic layers comprises a second pyrotechnic compound, wherein burning of the first pyrotechnic compound emits a first color and burning of the second pyrotechnic compound emits a second color and the first color and the second color are different.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0024] Referring now to the figures, which are exemplary embodiments, and wherein the like elements are numbered alike.

[0025] FIGS. 1A to 1D are cross-sectional views of embodiments of a flare;

[0026] FIG. 2 is a cross-section view of an embodiment of a flare;

[0027] FIGS. 3A to 3E are cross-section views of a burning progression of an embodiment of a flare; and

[0028] FIG. 4 is a cross-section view of an embodiment of a flare.

DETAILED DESCRIPTION

[0029] Disclosed herein is a multicolor, strobing pyrotechnic flare. The flare comprises alternating pyrotechnic layers.

[0030] Traditional pyrotechnic flares generally are monolithic, end-burning pyrotechnic grains with the visibility of the flare dependent on the brightness and flickering of the burning flame. Traditional pyrotechnic flares provide steadily, monochromatic emission that can be less perceptible leading to the need for a strobing, multicolor light effect to maximize visibility and make it easier to distinguish from other, steady light sources. The disclosed multicolor, strobing pyrotechnic flare can be customized to provide unique light effects, such as color switching, irregular or regular flashing of light, and so forth. The flares can be tailored for a variety of applications and environments such as roadside incidents, law enforcement activities, military purposes and maritime situations. The flare combines the benefits of long shelf life, reliability, reduced cost, and high brightness of pyrotechnic flares with the tailorable light colors and strobing effects of electronic battery-powered flares.

[0031] The exemplary embodiments disclosed herein are illustrative of a flare designed to provide a multicolor, strobing pyrotechnic effect. It should be understood, however, that the disclosed embodiments are merely examples of the present disclosure, which may be embodied in various forms. Therefore, details disclosed herein with reference to example flares and associated processes of fabrication and use are not to be interpreted as limiting, but merely as the basis for teaching one skilled in the art how to make and use the flare of the present disclosure.

[0032] The multicolor strobing pyrotechnic flare includes a plurality of alternating pyrotechnic layers. The plurality of alternating pyrotechnic layers can be provided in a stack. The plurality of alternating pyrotechnic layers can include a first pyrotechnic layer and a second pyrotechnic layer. The first pyrotechnic layer can include a first pyrotechnic compound and the second pyrotechnic layer can include a second pyrotechnic compound. When each pyrotechnic layer is burning, the contained pyrotechnic compound can emit a color. For example, when burning the first pyrotechnic compound, the first pyrotechnic compound can emit a first color and when burning the second pyrotechnic compound, the second pyrotechnic compound can emit a second color. The first color and the second color can be different.

[0033] FIGS. 1A to 1D illustrate cross-section views of embodiments of a flare 100 comprising a plurality of pyrotechnic layers. In FIG. 1A, an alternating pattern of a first pyrotechnic layer 101 and a second pyrotechnic layer 102 are shown in a regular repeating AB pattern. FIG. 1B illustrates an alternating pattern of the first pyrotechnic layer 101, the second pyrotechnic layer 102, and a third pyrotechnic layer 103 in a regular repeating ABC pattern. FIG. 1C illustrates an alternating stack of the first pyrotechnic layer 101, the second pyrotechnic layer 102, and the third pyrotechnic layer 103 in an irregular pattern. While FIGS. 1A to 1C illustrate embodiments of a flare 100 with stacks of a plurality of pyrotechnic layers where each layer in the stack has substantially the same volume, at least one or more dimension of each layer can vary. For example, the height of a layer in the stack may be the same or substantially different than an adjacent layer. FIG. 1D illustrates a cross-sectional view of an embodiment of a flare in a spherical layered format. As shown in FIG. 1D, the inner pyrotechnic layers can be encapsulated by the subsequent pyrotechnic layers in an alternating pattern.

[0034] FIG. 2 illustrates a cross-sectional view of a flare 100 comprising the first pyrotechnic layer 101, the second pyrotechnic layer 102, and a delay layer 104. The delay layer can be disposed between each pyrotechnic layer to enhance the strobing effect of the flare during use. In an embodiment, a delay layer is disposed between some, but not all, of the pyrotechnic layers. A plurality of pyrotechnic layer types can be used in the flare 100. Two different types of pyrotechnic layers are shown in FIG. 2, the first pyrotechnic layer 101 and the second pyrotechnic layer 102.

[0035] In some embodiments, the flare 100 can comprise a plurality of alternating pyrotechnic layers including n pyrotechnic layers. The n pyrotechnic layers can comprise m pyrotechnic layer types, where n can be 2 to 2,000 and m can be 2 to 2,000. The n of the pyrotechnic layers refers to a first pyrotechnic layer, a second pyrotechnic layer, and so forth, up to the n.sup.th pyrotechnic layer. The m of different pyrotechnic layer types refers to a first pyrotechnic layer type, a second pyrotechnic layer type, and so forth up to the m.sup.th pyrotechnic layer type. A different pyrotechnic layer type indicates a pyrotechnic layer with a different pyrotechnic compound or a different combination of pyrotechnic compounds than another pyrotechnic layer in the flare.

Pyrotechnic Layer

[0036] Each pyrotechnic layer includes a pyrotechnic compound. The alternating pyrotechnic layers can use a different pyrotechnic compound or a different combination of pyrotechnic compounds. As the pyrotechnic layer burns, the burning pyrotechnic compound can emit a color. The different pyrotechnic compounds or different combinations of pyrotechnic compounds can provide different emitted colors of burning characteristics during burning of the flare. Pyrotechnic layers containing different pyrotechnic compounds or different combinations of pyrotechnic compounds can be stacked upon one another in an alternating manner to provide a multi-color, strobing effect during burning of the flare 100. The pyrotechnic layers can be layered in a regular, repeating alternating pattern. For example, an AB, an ABC, an ABCD pattern, and so forth.

[0037] The alternating pyrotechnic layers can include m different pyrotechnic layer types, where m can be 2 to 2,000 or as few as 2 to 50. For example, the plurality of alternating pyrotechnic layers can include a first pyrotechnic layer comprising a first pyrotechnic layer type, a second pyrotechnic layer comprising a second pyrotechnic layer, and so forth, up to the m.sup.th pyrotechnic layer type. In an embodiment, the plurality of alternating pyrotechnic layer types can consist of a first pyrotechnic layer type and a second pyrotechnic layer type. Each of the different pyrotechnic layer types can include a different pyrotechnic compound or a different combination of pyrotechnic compounds such that burning of the different pyrotechnic layer type emits a different color or burning effect than other different pyrotechnic layer types in the plurality of alternating pyrotechnic layers.

[0038] Burning of a pyrotechnic layer can emit a color of varying wavelengths in the visible light spectrum. In some embodiments, the burning pyrotechnic layer can emit light in the infrared spectrum, in the ultraviolet spectrum, or a combination thereof. In some embodiments, the burning pyrotechnic layer can emit light only in the infrared spectrum, in the ultraviolet spectrum, or in the visible light spectrum. For example, the pyrotechnic layer can emit a color with a wavelength of 380 nanometers (nm) to 450 nm, 450 nm to 495 nm, 495 nm to 570 nm, 570 nm to 590 nm, 590 nm to 620 nm, or 620 nm to 750 nm. The burning pyrotechnic layer can emit visible color of overlapping ranges of the preceding example wavelength grouping, such as 590 nm to 750 nm. The burning pyrotechnic layer can emit a combination of colors, such as emitting a color with a wavelength of 450 nm to 495 nm and 620 nm to 750 nm. As shown in FIGS. 3A to 3E, a burning flare with flame 300, emits light 301 during burning of the first pyrotechnic layer 101. As the flame 300 burns the second pyrotechnic layer 102, light 302 is emitted.

[0039] The thickness of the alternating pyrotechnic layers can be the same or different. For example, the first pyrotechnic layer can be twice as thick as the second pyrotechnic layer. Different alternating thicknesses of the pyrotechnic layers can tailor the strobing and color effect during burning of the flare. In some embodiments, the thicknesses of the pyrotechnic layers can vary in an irregular pattern. For example, a stack of pyrotechnic layers can have a thickness order of 0.5 mm, 30 mm, 20 mm, 10 mm, and so forth, where the thickness of the pyrotechnic layer is independent of the alternating pyrotechnic layer type thereby providing an irregular multicolor strobing pattern (a short, long, medium, short, and so forth). In some embodiments, the thickness of a pyrotechnic layer can be 0.5 millimeters (mm) to 10 mm, 0.25 mm to 25 mm, or 1 mm to 10 mm. The layer thickness determines the time between transitions in states. The transitions between states can the enhance the observability benefit. The states can be colors or absence of visible color (i.e. colorless emission or emission outside of the visible spectrum). The burn rate of the pyrotechnic layer can be 10 millimeters (distance of the of height or radius) per minute (mm/min) to 300 mm/min, 25 mm/min to 200 mm/min, 50 mm/min to 150 mm/min, or 100 mm/min. The burn rate of adjacent pyrotechnic layers may be the same or different.

[0040] In some embodiments, a delay layer 104 is interposed between the alternating pyrotechnic layers to enhance the strobing effect of the flare 100. In an embodiment, the delay layer is interposed between some or all of the alternating pyrotechnic layers. The burn rate of the delay layer can be the same or different as the burn rate of a pyrotechnic layer.

[0041] Burning of the propellant layer can be irregular where the burning surface may not regress linearly or undesirable conical burning of multiple layers simultaneously may occur, for example, ignition of a second pyrotechnic layer may occur during burning of a first pyrotechnic layer. To counteract irregular burning of the propellant layer, the flare 100 may include a fast burning propellant layer or a fast burning delay layer to encourage the burning surface to be more planar or promote linear burning of the flare.

[0042] Alternatively, to counteract irregular burning of the propellant layer, the flare may be provided in a dispersed format. FIG. 4 provides a cross-sectional view of an embodiment of a dispersed format flare. As shown in FIG. 4, the first pyrotechnic layer 101 can encapsulate prills (or pellets) of a different pyrotechnic layers. A plurality of alternating pyrotechnic layers can include the different pyrotechnic layer dispersed in the first pyrotechnic layer. The prills may comprise one or more different pyrotechnic layers, up to n1 different pyrotechnic layers of m1 different types of pyrotechnic layers, n can be 2 to 2,000 and m can be 2 to 2,000 or as few as 2 to 50. In FIG. 4, a second pyrotechnic layer 102 and a third pyrotechnic layer 103 are dispersed throughout the first pyrotechnic layer 102. The prills may be provided in a regular or irregular pattern throughout the first pyrotechnic layer 102. The distribution of the prills can be in layers such that the third pyrotechnic layer 103 is disposed between layers of the second pyrotechnic layer 102. The concentration of the second pyrotechnic layer 102 can be greater than or less than the concentration of the third pyrotechnic layer within the first pyrotechnic layer. The prills may be smaller and faster burning than the first pyrotechnic layer. The incorporation of the prills of a different pyrotechnic layer within the first pyrotechnic layer can serve to spike a steady emission of the burning first pyrotechnic layer with a different, color shifting emission to enhance observability.

Pyrotechnic Compound

[0043] Each pyrotechnic layer comprises a pyrotechnic compound. For different pyrotechnic layer types, the pyrotechnic layer can include a different pyrotechnic compound or a different combination of pyrotechnic compounds. The pyrotechnic compounds in the alternating pyrotechnic layers can emit different colors (i.e., light of a different wavelength or a different wavelength range) when burning and can have different burn rates. For example, the first pyrotechnic compound can have a first burn rate and the second pyrotechnic compound can have a second burn rate and the first burn rate and the second burn rate can be different. In an embodiment, the first pyrotechnic layer can include the first pyrotechnic compound and a third pyrotechnic compound and the third pyrotechnic compound can have a third burn rate that is different than the first burn rate. Different combinations of pyrotechnic compounds can include blends of materials such as mixtures of pure prills of pyrotechnic compound in a blend of a less luminous pyrotechnic compound. In some embodiments, the pyrotechnic compound can be provided in a blend with other fillers and carriers to provide the desired burning properties with improved storage stability. Suitable pyrotechnic compounds to tailor the emission spectrum include, but are not limited to, an organic fuel, a metal salt, or a combination thereof. The organic fuel can include red gum, dextrin, or a combination thereof. The metal salt can include strontium nitrate, barium nitrate, sodium chloride, copper chloride, or a combination thereof.

Delay Layer

[0044] A delay layer, or combustion-sustaining layer with little to no emission relative to the preceding pyrotechnic layers can be interposed between some or all of the alternating pyrotechnic layers. The delay layer can emit low levels of visible light or no visible light when burning. In an embodiment, the delay layer can burn with an illuminance of less than 0.05 lux. The inclusion of the delay layer between the alternating pyrotechnic layers can serve to enhance the strobing effect by delaying color switch over during burning. Suitable examples of materials used in a delay layer include an organic fuel, such as charcoal, a sugar, saw dust, or a combination thereof. The materials used in the delay layer can be selected to burn with sufficient heat of combustion without significant emission in the spectrum of the surrounding pyrotechnic layers.

[0045] A method of providing a pyrotechnic effect can include providing a multicolor strobing pyrotechnic flare. The flare can include a plurality of alternating pyrotechnic layers. The plurality of alternating pyrotechnic layers can include n pyrotechnic layers including m different pyrotechnic layer types, wherein n is 2 to 2000 and m is 2 to 200 or as few as 2 to 50. The method can further comprise igniting a surface of the stack. Igniting the surface of the stack sequentially burns a first pyrotechnic layer of the n pyrotechnic layers and the second pyrotechnic layer of the n pyrotechnic layers. As the first pyrotechnic layer is burned, the first pyrotechnic layer can emit a first color. As the second pyrotechnic layer is burned, the second pyrotechnic layer can emit a second color. The first color and the second color can be different. In an embodiment, the burning of the m different pyrotechnic layer types can emit m different colors. In an embodiment, the burning of the first pyrotechnic layer and the second pyrotechnic layer can occur simultaneously, separately, or a combination thereof.

[0046] A method of manufacturing a multicolor strobing pyrotechnic flare can include disposing a plurality of pyrotechnic layers in an alternating stack, wherein the plurality of alternating pyrotechnic players can comprise n pyrotechnic layers including m pyrotechnic layer types, n can be 2 to 2,000 and m can be 2 to 2,000 or as few as 2 to 50. A delay layer can be interposed between each of the alternating pyrotechnic layers. A first pyrotechnic layer of the n pyrotechnic layers can comprise a first pyrotechnic compound and a second pyrotechnic layer n pyrotechnic layers can comprise a second pyrotechnic compound, wherein burning of the first pyrotechnic compound can emit a first color and burning of the second pyrotechnic compound can emit a second color and the first color and the second color can be different

[0047] The alternating stack of the plurality of pyrotechnic layers can be assembled layer by layer by additive manufacturing or by pressing a first pyrotechnic layer of the n pyrotechnic layers on a second pyrotechnic layer of the n pyrotechnic layers under pressure and pressing a second layer of the first pyrotechnic layer on the opposing surface of the second pyrotechnic layer and repeating the stacking and pressing process until a desired quantity of stacked pyrotechnic layers are attained. In an embodiment, the alternating stack of the plurality of pyrotechnic layers can be assembled by dispersing n1 pyrotechnic layers in the first pyrotechnic layer. The n1 pyrotechnic layers can comprise 1 to 1,999 different pyrotechnic layers and the 1 to 1,999 different pyrotechnic layer can comprise 1 to 1,999 different pyrotechnic layer types. The n1 pyrotechnic layers can be distributed within the first pyrotechnic layer in a dispersed format.

[0048] In an embodiment, a method can include assembly of an alternating stack of the plurality of pyrotechnic layers by an alternating coating process. The alternating coating process can include coating a first layer of a first pyrotechnic layer of the n pyrotechnic layers with a second pyrotechnic layer of the n pyrotechnic layers, coating an opposing surface of the second pyrotechnic layer with a second layer of the first pyrotechnic layer. The alternating coating process is repeated until a desired quantity of stacked pyrotechnic layers are obtained.

[0049] It is noted that the flares, assemblies, and methods of the present disclosure can provide cost-effective pyrotechnic flares that provide bright, multicolor strobing. The use of flares can improve visibility of flares for roadside incidents, law enforcement activities, military purposes and maritime situations. The flares can also provide a cost-effective and environmentally friendly alternative to traditional pyrotechnic flares.

[0050] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.

[0051] The ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., ranges of up to 25 wt. %, or, more specifically, 5 wt. % to 20 wt. %, is inclusive of the endpoints and all intermediate values of the ranges of 5 wt. % to 25 wt. %, and so forth). Combinations is inclusive of blends, mixtures, alloys, reaction products, and the like. The terms first, second, and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms a and an and the do not denote a limitation of quantity and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Or means and/or unless clearly stated otherwise. Reference throughout the specification to some embodiments, an embodiment, and so forth, means that a particular element described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments. A combination thereof is open and includes any combination comprising at least one of the listed components or properties optionally together with a like or equivalent component or property not listed.

[0052] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0053] Although the flares, assemblies, and methods of the present disclosure have been described with reference to example embodiments thereof, the present disclosure is not limited to such example embodiments and/or implementations. Rather, the flares, assemblies, and methods of the present disclosure are susceptible to many implementations and applications, as will be readily apparent to persons skilled in the art from the disclosure hereof. The present disclosure expressly encompasses such modifications, enhancements and/or variations of the disclosed embodiments. Since many changes could be made in the above construction and many widely different embodiments of this disclosure could be made without departing from the scope thereof, it is intended that all matter contained in the drawings and specification shall be interpreted as illustrative and not in a limiting sense. Additional modifications, changes, and substitutions are intended in the foregoing disclosure. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure.