Archive for April 2007

Part VII. On Composition Series for Practical Use

ABSTRACT:

(1) The spectroscopic studies in the previous Parts are summarized so as to apply the principle of flame color creation for practical use.

(2) According to the results of (1), various samples of red, yellow, green and blue of several composition series are prepared. Their flame colors are examined by the naked eye and good colors are selected. According to these, effective color zones are written as enclosed areas in triangle graphs.

(3) As far as these studies are concerned the important results that seem to be common for each series are as follows:

a) The width of an effective composition zone in a graph is very narrow for low temperature flames and fairly wide for high temperature flames.

b) Ammonium perchlorate is the best oxidizer, for it can produce HCl in a flame and creates deep color.

c) Polyvinyl chloride is also the best additional ingredient that can create a deep color by producing HCl gas in the flame like ammonium perchlorate. d) It is necessary to completely protect compositions from moisture for high temperature flames to prevent the magnesium and other ingredients from reacting with each other. For practical applications deep and brilliant color flames are obtained only in accord with this consideration.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 107-119
(Sh3_107)
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Part VI. Flame Spectra of Metal Aluminum Compositione

ABSTRACT: The previous Parts showed the effect of magnesium powder as a fuel in high temperature compositions. In this Part the effect of aluminum powder is examined. In general aluminum melts and is sprayed as sparks out of the flame. It is not as easily vaporized because of its high boiling point. With aluminum the intensity of the spectrum of color-producing bands is not as high as with magnesium.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 103-105
(Sh3_103)
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Part V: Flame Spectra of Blue Color Compositions

ABSTRACT: We can see three different flame colors (i.e., blue, light green and reddish orange) when we insert a small copper piece into a flame of a burner. The blue color is caused by CuCl bands with the strongest lines between 4269–4560 Å. Our goal is to use this color for fireworks. Blue is produced by some copper salts or copper metal powder in the presence of chlorine or hydrogen chloride gas, but if the concentration of gas is small, the blue color is interfered with by the light green color, which seems to be caused by a continuous spectrum of other copper chloride bands (5263–5531 Å).

The flame spectra are examined under various conditions. For low temperature flames, ammonium perchlorate is the best oxidizer and produces an excellent bright blue. For high temperature flames it is necessary to decrease the percentage of magnesium powder, because the CuCl bands seem to  dissociate with increasing magnesium.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 87-102
(Sh3_87)
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Part IV. Flame Spectra of Red, Yellow and Green Color Compositions

ABSTRACT: lame spectra of red, yellow and green color  compositions are examined under various conditions.

a. Red Flame

A red flame is produced by bands from strontium (Sr) salts. These bands consist of five main bands [i.e.,  (6013), (6203),  (6300),  (6428) and (6558)], where each number represents the wavelength of the maximum intensity in Angstroms (Å). The influence of chlorine on the  band is quite different from theothers, namely the  band is weakened by chlorine, whereas chlorine intensified the others, and this effect is greater with hydrogen chloride gas than with chlorine gas. This is very clearly observed especially in low temperature flames. The influence of strontium salts is very small. The effect of oxidizers that produce either chlorine or hydrogen chloride gas is quite remarkable. If we add ingredients that have chlorine, they can intensify each band only in high temperature flames. The effects of calcium (Ca) salts were also examined.

b. Yellow Flame

A yellow flame is produced by sodium (Na) salts. The spectrum consists of mainly Na-D lines, but in addition, a continuous spectrum from Na atoms appears between 5,800 and 6,100 Å and makes the flame color rather white, especially at high flame temperatures.

c. Green Flame

Only BaCl bands can produce green flames when barium (Ba) salts are used as the color agents. Compositions without chlorine cannot produce green color because only BaO bands appear, giving white color to the flames. In the presence of chlorine both BaCl and BaO bands appear. The effect of chlorine or hydrogen chloride gas in a flame seem to weaken the BaO bands and to intensify the BaCl bands. The effect of chlorine gas is less than that of hydrogen chloride gas. And so, ammonium perchlorate produces a better green color than potassium perchlorate. Adding some kind of chlorine compound (chlorine donor) is also effective to intensify the green color.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 57-86
(Sh3_57)
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Part III. On Backgrounds of Color Flame Spectra

ABSTRACT: Blank runs were made with nominal colorproducing compositions to investigate the lines, bands or continuous spectra that appear as background and interfere with the desired spectra of red, yellow, green, etc. These sample compositions consisted of solid materials such as oxidizers (ammonium perchlorate, potassium chlorate, potassium perchlorate, potassium nitrate, etc.), low temperature fuels (shellac, rosin, pine root pitch, etc.), and magnesium powder for the high temperature fuel.

For low flame temperatures sodium D (Na-D) lines (5890 and 5896 Å, caused by impurities contained mainly in the oxidizers), continuous spectra (caused by carbon particles and potassium atoms) and potassium (K) lines (5802, 5783, 5832, 5813; 5340, 5324, 5360, 5343; 5090, 5084, 5113, 5080; 4044, 4048 Å) are observed. For high flame temperatures Na-D lines are also observed, and in addition to the above, MgO bands and continuous spectra (the latter are caused by solid metal oxide particles and K atoms) are found.

The main interfering spectra are the Na-D lines and continuous spectra. Purification of ingredients is very important to remove Na-D lines and to obtain fine colored flames. For high flame temperatures, the addition of chlorine- containing compounds such as polyvinyl chloride, ammonium chloride, etc. to a composition is effective in decreasing the intensity of the continuous spectra, and it is assumed that the metal oxide of the solid phase is converted into the metal chloride of the vapor phase in the presence of chlorine or hydrogen chloride in the flame, but this should be ascertained by further experiments of higher accuracy. The addition of shellac is also effective in weakening the intensity of the continuous spectra and decreasing the black body temperature of the flame.

The permeability coefficients and black body temperature of flames of basic compositions are measured for reference .


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 39-56
(Sh3_39)
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Part II. Temperature Measurement of Flames by Means of the Line-Reversal Method

ABSTRACT:  Using the theory developed in Part I, flame temperatures for various fireworks compositions have been measured by means of line-reversal of the Na-D lines. (1) For low flame temperature compositions: Compositions that contain combustible organic materials (i.e., shellac, rosin, pine root pitch, etc.) are commonly used in ordinary fireworks. The author prepared various combinations of components to see the influence of oxidizers, fuels, color agents, etc. Temperatures are measured by method 1 from Part I. The result shows that the highest temperature appears at the base of the flame. Generally potassium perchlorate gives higher temperatures than ammonium perchlorate. Potassium nitrate always gives lower temperatures than other oxidizers.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 15-37
(Sh3_15)
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Part I. A Theoretical Development of the Line-Reversal Method for Flame Temperature Measurement

ABSTRACT:  A fireworks flame generally contains many solid or liquid particles, which cause a continuous spectrum. In order to apply the linereversal method of temperature measurement to such flames, the author introduced a theoretical equation, which denotes the ratio of the intensity of the resonance lines to that of the neighboring part of the spectrum when a standard light beam is introduced into the spectroscope through the flame. This equation shows very clearly that as long as the flame does not contain so many particles that it prevents the standard light beam from permeating the flame, the line-reversal method is always effective. Using this equation, the author proposes a method of measuring flame temperatures that are higher than the maximum brightness temperature of the standard light. The author applied this method to two examples of hightemperature fireworks flames of some magnesium powder compositions and obtained the temperatures of 3,159 and 3,214 K.


Ref: Selected Pyrotechnic Publication of Dr. Takeo Shimizu, Part 3,  pp 1-14
(Sh3_1)
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Safety Rating System for Pyro-Chemicals

The safety ratings are given for four areas of hazard concern:


Ref: Selected Pyrotechnic Publication of K.L. and B.J Kosanke, Part 3, (1993-1994), pp 92-93
(K3_92)
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Basics of Hazard Management

K.L. and B.J. Kosanke, and C. Jennings-White

The consequences of accidents can be devastating to those immediately involved and their relatives. However, the ramifications of accidents can extend much further. This is illustrated in what Richard Green (Idaho National Engineering Laboratory)[1] has described as “The Four Horsemen of Our Own Apocalypse”, specifically:

ACCIDENTS, INJURIES, LITIGATION, and LEGISLATION.

In effect, this is a chain in which Accidents produce Injuries, which often result in Litigation, the notoriety from which helps generate pressure for more restrictive regulation (Legislation). With this view, it is accidents involving individuals that produce increased regulation, or at least provide an excuse for increased regulation. Because regulations not only affect those individuals having accidents, but also the fireworks community as a whole, the whole community has a stake in eliminating fireworks accidents. It is the hope of the authors that this article will contribute by stimulating thought and discussion of some basic Hazard Management concepts.


Ref: Selected Pyrotechnic Publication of K.L. and B.J Kosanke, Part 3, (1993-1994), pp 88-91
(K3_88)
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Hypothesis Explaining Muzzle Breaks

K.L. and B.J. Kosanke

ABSTRACT: Muzzle breaking aerial shells continue to be a significant cause of serious injury for persons discharging display fireworks. The problem is greatest for manually fired displays, where the person igniting the fireworks remains in close proximity to the mortar. Over the years, many possible causes for muzzle breaks have been suggested. Unfortunately, most of these explanations are incapable of withstanding close scientific scrutiny, and there has been no published study that has tested any of the potential explanations. Without knowing the cause(s) for muzzle breaks with some certainty, it is difficult (or impossible) for a manufacturer of aerial shells to know what measures might be taken to reduce or eliminate the chance of their occurrence.

Probably the best known characteristic of muzzle breaks is that they occur almost exclusively in the largest diameter (most potentially dangerous) aerial shells. Probably at least 90% of muzzle breaks occur in aerial shells 205 mm (8 in.) or larger. This is true, even though at least 90% of all aerial shells fired are smaller than 205 mm (8 in.). Thus any theory for the cause of muzzle breaks must account for this observation. The authors hypothesize that either setback or very small fire leaks lead to the occurrence of muzzle breaks, and that the dynamics of the propulsion of fireworks from mortars and the explosion of aerial shells is such that the chances for muzzle break occurrence is greatest for large diameter shells. In an attempt to test the hypothesis, a series of measurements were performed to determine the exit times of aerial shells from mortars and the times to explosion of shells after internal ignition. Results of these measurements are each somewhat surprising; they tend to support the hypothesis and provide insight into the mechanisms of aerial shell flowerpots.


Ref: Selected Pyrotechnic Publication of K.L. and B.J Kosanke, Part 3, (1993-1994), pp 76-87
(K3_76)
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