Meyer R., Koehler J., Homburg A. Explosives. Wiley-VCH, 2002 / Explosives 5th ed by Koehler, Meyer, and Homburg (2002)
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Bridgewire Detonator |
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Breech*)
Patronenkammer; chambre pour cartouche
Reloadable pressure vessel used to contain a propellant cartridge.
Bridgewire Detonator
Brückenzünder; amorce a` pont
Bridgewire detonators are used in industrial detonation for the detonation of explosive charges. They contain an incandescent bridge made of thin resistance wire, which is made to glow by application of an electric pulse. An igniting pill is built around the wire by repeated immersion in a solution of a pyrotechnical material followed by drying. The igniting flash acts directly onto the detonating surface in the case of instantaneous detonators; in delayed-action detonators it is sent over a delay device onto the detonating surface of a blasting cap which has been pressed onto the detonating pill so as to produce a water-tight bond with it. Non-armed bridgewire detonators have an open casing, into which a blasting cap may be inserted.
The “U”-detonators which are now employed in mining in the Germany need a pulse of 16 mW · s/ohm; the earlier detonators required only 3 mW · s/ohm. Thus new detonators afford much better protection against stray currents. Locations exposed to electrostatic stray charges (thunderstorms) and which are therefore particularly dangerous, are equipped with low-sensitivity detonators, which require as much as 2500 mW · s/ohm for actuation and may therefore be considered safe (“HU”-detonators).
The delayed-action detonators may be set for a delay of half a second (half-second detonators) or for a delay of 2 – 34 ms (millisecond detonators). Blasting with the latter type of detonators results in a larger yield of blasted stone fragments; moreover, a smaller shock will be imparted to the ground around the explosion site.
In coal mining only copper casings rather than the conventional aluminum casings are permitted because of the danger of firedamp. Explosive charges equipped with bridgewire detonators are fired by wireconnected W Blasting Machines from a safe location. If several charges are to be exploded at the same time, the detonators are connected in series with the connecting wire. Parallel connection of the detonators is used only in special cases (extremely wet conditions with danger of shunting); special blasting machines must be employed for this purpose.
* Text quoted from glossary.
Brisance |
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Brisance
Brisanz
The performance of an explosive cannot be expressed by means of a single characteristic parameter. Brisance is the destructive fragmentation effect of a charge on its immediate vicinity. The relevant parameters are the detonation rate and the loading density (compactness) of the explosive, as well as the gas yield and the heat of explosion. The higher the loading density of the explosive (molding or pressing density), the higher its performance concentration per unit volume; also, the faster the reaction rate, the stronger the impact effect of the detonation. Moreover, an increase in density is accompanied by an increase in the detonation rate of the explosive, while the shock wave pressure in the detonation front (W Detonation) varies with the square of the detonation rate. Thus it is very important to have the loading density as high as possible.
This is particulary true for W Shaped Charges.
Kast introduced the concept of “brisance value”, which is the product of loading density, specific energy and detonation rate.
Brisance tests are upsetting tests according to Kast and Heß; the compression of a copper cylinder is determined by actuating a piston instrument; alternatively, a free-standing lead cylinder is compressed by the application of a definite cylindrical load of the explosive being tested: W Upsetting Tests.
Bulk Density*)
Schüttdichte; densit´ apparente
The mass per unit volume of a bulk material such as grain, cement, coal. Used in connection with packaging, storage or transportation.
Bulk Mix*)
Sprengstoffmischung für unpatronierte Anwendung; explosif en vrac
A mass of explosive material prepared for use in bulk form without packaging.
Bulk Mix Delivery Equipment; Misch-Lade-Fahrzeug; v´ehicule m´el- angeur-chargeur
Equipment (usually a motor vehicle with or without a mechanical delivery device) that transports explosives, blasting agents or ingre-
* Text quoted from glossary.
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Bullet-resistant*) |
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dients for explosive materials in bulk form for mixing and/or loading directly into blast holes.
Bulk Strength
Cartridge Strength: Volume Strength
The strength per unit volume of an explosive calculated from its
W Weight Strength and W Density.
Bulldoze*)
Auflegeladung; p´etardage
A mud covered or unconfined explosive charge fired in contact with a rock surface without the use of a bore hole. Synonymous with Adobe Charge and W Mud Cap.
Bullet Hit Squib
Filmeffektzünder; Squib
Bullet hit Squibs are used in motion pictures and television to simulate ballistic impact of fired projectiles.
What is refered to here are small, pyrotechnic, electrical devices with varying charges and containing several milligrams of a compound consisting of W Lead Azide, W Lead Styphnate, W Diazodinitrophenol and Tetrazole Derivatives.
The initiating explosive material must be specially treated and phlegmatized to avoid the undesired byproduct of smoke and flash. One method achieves this by using an admixture of alkaline earth sulfates or by means of micro-encapsulation of the explosive crystals.
These special electrical igniters are produced by the company J. Köhler Pyrotechnik in Schardenberg/Austria.
Bullet-resistant*)
Kugelsicher; r´esistant au balles
Magazine walls or doors of construction resistant to penetration of a bullet of 150-grain M2 ball ammunition having a nominal muzzle velocity of 2700 feet per second fired from a .30 caliber rifle from a distance of 100 feet perpendicular to the wall or door.
* Text quoted from glossary.
Bullet-sensitive Explosive Material |
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When a magazine ceiling or roof is required to be Bullet-Resistant, the ceiling or roof shall be constructed of materials comparable to the side walls or of other materials which will withstand penetration of the bullet above described when fired at an angle of 45 degrees from the perpendicular.
Tests to determine bullet resistance shall be conducted an test panels or empty magazines which shall resist penetration of 5 out of 5 shots placed independently of each other in an area at least 3 feet by 3 feet. If hardwood or softwood is used, the water content of the wood must not exceed 15 %.
Bullet-sensitive Explosive Material*)
Beschussempfindlicher Sprengstoff; explosif sensible a l’impact de balles
Explosive material that can be detonated by 150-grain M2 ball ammunition having a nominal muzzle velocity of 2700 feet per second when the bullet is fired from a .30 caliber rifle at a distance of not more than 100 feet and the test material, at a temperature of 70 °C to 75°F., is placed against a backing material of 1/2-inch steel plate.
(W Impact Sensitivity.)
Burden*)
Vorgabe; distance entre 1 a charge et la surface du massif
That dimension of a medium to be blasted measured from the borehole to the face at right angles to the spacing. It means also the total amount of material to be blasted by a given hole, usually measured in cubic yards or in tons.
Bureau of Alcohol, Tobacco and Firearms (BATF)*)
A bureau of the (US-)Department of the Treasury having responsibility for the enactment and enforcement of regulations related to commerce in explosives under Part 181 of Title 26 of the Code of Federal Regulations.
* Text quoted from glossary.
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Burning Rate |
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Bureau of Explosives*)
A bureau of the Association of American Railroads which the U.S. Department of Transportation may consult to classify explosive material for the purposes of interstate transportation.
Bureau of Mines
W U.S. Bureau of Mines.
Bureau of Mines Test
W Impact Sensitivity.
Burning Rate
Abbrandgeschwindigkeit; velocity of combustion; vitesse de combustion
The linear burning rate of a propellant is the velocity with which a chemical reaction progresses as a result of thermal conduction and radiation (at right angles to the current surface of the propellant). It depends on the chemical composition, the pressure, temperature and physical state of the propellant (porosity; particle size distribution of the components; compression). The gas (fume) cloud that is formed flows in a direction opposite to the direction of burning.
The burning rate describes the velocity with which the volume of the burning propellant changes. It is proportional to the linear burning rate and in addition it depends on the specific shape of the propellant (size of the powder elements and conformation, e. g. flakes, spheres, tubes, multi-perforated tubes etc. extending to the most complicated shapes of rocket propellant charges).
In rocket engineering, “Burning rate” means specifically the stationary progress of burning rate in the rocket chamber.
The following relationship exists between the burning rate dz/dt and the linear burning
rate e˙:
ddzt = SV(0)(0) V f(z) V e˙
where e˙ is given by
* Text quoted from glossary.
Burning Rate |
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e˙ = e˙(pref) V ( |
p(z) |
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pref |
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means the ratio of the volume burnt to that originally pre- |
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sent [V(0) – V] / V(0) |
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S(0) / V (0) means the ratio of the initial surface area to the initial |
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volume of the powder, |
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f(z) |
means the shape function of the powder, which takes into |
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account the geometrical conditions during burning rate |
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(sphere, flake, cylinder, n-hole powder) |
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(f(z) = current surface area/initial surface area) |
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e˙(pref) |
means the linear burning velocity at the reference gas |
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pref |
pressure pref |
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is the reference gas pressure and |
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a |
is the pressure exponent. |
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The equation for the burning rate rate dz/dt can also be written in the form
ddzt = A V f(z) V pa
and is then called Charbonnier’s Equation.
The parameter A = (S(0) V V(0)) V f(z) V e˙(pref) /paref is called the “vivacity” or “quickness” factor“.
The pressure exponent a typically has a value close to 1 for propellant charge powder (burning rate at high pressure level). At low pressure ranges (rocket burning rate) it can be brought close to zero (“plateau burning rate”) or even less than zero (“mesa burning rate”) by suitable additives to the propellant.
When the geometry of the propellant is known, the linear burning rate and the pressure exponent of a propellant can be determined experimentally in a W ballistic bomb.
If the gases flow continously out, as in the case of a rocket motor, the pressure remains almost constant throughout the combustion period. The linear burning rate and its variation with the temperature and pressure may be determined in a W Crawford Bomb. The temperature coefficient of the burning rate is the variation per degree of temperature increase at constant pressure. The dependance on pressure is characterized by the pressure exponent (see above).
For details on relevant theoretical and practical relationships see:
Barrère, Jaumotte, Fraeijs de Veubeke, Vandenkerckhove: “Raketenantriebe”, Elsevier Publ. Co., Amsterdam 1961, p. 265 ff.; Dadieu, Damm, Schmidt: “Raketentreibstoffe”, Springer, Wien 1968.
Other relevant keywords are: W Solid Propellant Rockets, W Specific Impulse, W Thermodynamic Calculation of Decomposition Reactions, W Thrust.
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Butanediol Dinitrate |
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Bus Wire*)
Antenne für Parallelschaltung; antenne pour le couplage en parallele
Two wires that form an extension of the lead line and connecting wire and common to all caps in parallel. In parallel firing, each of the two wires of each electric blasting cap is connected to a different bus wire. For series in parallel firing each side of the series is connected to a different bus wire (W Parallel Connection).
Butanediol Dinitrate
1,3-Butylenglykoldinitrat; dinitrate de butyl´eneglycol
colorless liquid
empirical formula: C4N8N2O6 molecular weight: 180.1 oxygen balance: – 53.3 % nitrogen content: 15.56 % density: 1.32 g/cm3
lead block test: 370 cm3/10 g
Butanetriol dinitrate is insoluble in water, but is soluble in solvents for nitroglycerine; it is more volatile than nitroglycerine. Soluble guncotton is readily gelatinized. The nitrate is formed by reaction of butylene glycol with a nitric acid-sulfuric acid mixture as in the nitroglycerine synthesis, but the product is very easily destroyed by oxidation; the reaction mixture decomposes generating heat and nitrous gases. The product cannot be obtained under industrial conditions and has not found practical application for this reason.
* Text quoted from glossary.
Butanetriol Trinitrate |
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Butanetriol Trinitrate
1,2,4-Butantrioltrinitrat; trinitrate de butanetriol
pale yellow liquid
empirical formula: C4H7N3O9 molecular weight: 241.1
energy of formation: – 379.2 kcal/kg = –1586.4 kJ/kg enthalpy of formation: – 402.5 kcal/kg = –1683.9 kJ/kg oxygen balance: –16.6 %
nitrogen content: 17.43 % refractive index: n20D = 1.4738
volume of explosion gases: 836 l/kg heat of explosion
(H2O liq.): 1439 kcal/kg = 6022 kJ/kg (H2O gas): 1327 kcal/kg = 5551 kJ/kg
density: 1.52 g/cm3 (20/4) solidification point: – 27 °C = –17°F impact sensitivity: 0.1 kp m = 1 N m
1,2,4-Butanetriol is nitrated with a mixture of nitric and sulfuric acids. The nitrated product is very stable. It is, like nitroglycerine, gelatinized by nitrocellulose.
Butanetriol trinitrate was used in the manufacture of tropic-proof double base powders. Isomers of butantriol trinitrate were also studied and utilized in practical work; these include methyl glycerol trinitrate and 1,2,3-butanetriol trinitrate, which have similar properties.
Calcium Nitrate
Calciumnitrat; Kalksalpeter; nitrate de calcium
hydrated: Ca(NO3)2 · 4H2O colorless crystals
anhydrous product: Ca(NO3)2 white powder
The following data refer to the anhydrous product:
molecular weight: 164.1
energy of formation: –1352.1 kcal/kg = – 5657.3 kJ/kg enthalpy of formation: –1366.6 kcal/kg = – 5717.7 kJ/kg
, Fifth Edition Rudolf Meyer, Josef Köhler, Axel Homburg
Butanetriol Trinitrate
1,2,4-Butantrioltrinitrat; trinitrate de butanetriol
pale yellow liquid
empirical formula: C4H7N3O9 molecular weight: 241.1
energy of formation: – 379.2 kcal/kg = –1586.4 kJ/kg enthalpy of formation: – 402.5 kcal/kg = –1683.9 kJ/kg oxygen balance: –16.6 %
nitrogen content: 17.43 % refractive index: n20D = 1.4738
volume of explosion gases: 836 l/kg heat of explosion
(H2O liq.): 1439 kcal/kg = 6022 kJ/kg (H2O gas): 1327 kcal/kg = 5551 kJ/kg
density: 1.52 g/cm3 (20/4) solidification point: – 27 °C = –17°F impact sensitivity: 0.1 kp m = 1 N m
1,2,4-Butanetriol is nitrated with a mixture of nitric and sulfuric acids. The nitrated product is very stable. It is, like nitroglycerine, gelatinized by nitrocellulose.
Butanetriol trinitrate was used in the manufacture of tropic-proof double base powders. Isomers of butantriol trinitrate were also studied and utilized in practical work; these include methyl glycerol trinitrate and 1,2,3-butanetriol trinitrate, which have similar properties.
Calcium Nitrate
Calciumnitrat; Kalksalpeter; nitrate de calcium
hydrated: Ca(NO3)2 · 4H2O colorless crystals
anhydrous product: Ca(NO3)2 white powder
The following data refer to the anhydrous product:
molecular weight: 164.1
energy of formation: –1352.1 kcal/kg = – 5657.3 kJ/kg enthalpy of formation: –1366.6 kcal/kg = – 5717.7 kJ/kg
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Cap Sensitivity |
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oxygen balance: +48.8 % nitrogen content: 17.07 % melting point: 561 °C = 1042°F very hygroscopic
Calcium nitrate can be used as a oxidizer component of W Slurries.
Camphor
Campher, Kampfer; camphre
empirical formula: C10H16O molecular weight: 152.3
energy of formation: – 480 kcal/kg = – 2008 kJ/kg enthalpy of formation: – 513 kcal/kg = – 2146 kJ/kg oxygen balance: – 283.8 %
density: 0.98 – 0.99 g/cm3
melting point: 177–178 °C = 351 – 353°F boiling point: 209 °C = 408°F
This compound is utilized in celluloid industry, and also as gelatinizer in nitrocellulose gunpowders.
Specifications
net content: not less than |
99 % |
(analysis by titration with |
176 °C = 350°F |
hydroxylamine) |
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melting point: not less than |
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insolubles in alcohol and ether: |
0.1 % |
not more than |
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chlorides: not more than |
traces |
Cap Sensitivity
Sprengkapsel-Empfindlichkeit; sensibilit´ au choc d´etonateur
Tests are carried out to determine the reaction of an explosive to a detonating cap. The results are used to determine the classification of the explosive as a transport hazard. The U.S. Department of Transportation has placed W Blasting Agents into a hazard category subject to regulations similar to those applicable to the former NCN classification, i.e. much reduced in stringency. Explosives classified as blasting agents are those which can not be initiated by means of an explosive cap.