Pyrotechnic Delays

Pyrotechnic Delays in the United Kingdom , RARDE Rept FXD/70/026 (1963) 6) Anon,... 

For the particle size measurements of boron and barium dichromate, components of pyrotechnic delay compns, Freeman (Ref 46) evaluated the MSA. Particle Size Analyzer versus microscopy, gravitational liq sedimentation,... 

Freeman, Particle Size Measurement of Components, of Pyrotechnic Delay Compositions", PATR 4693 (1975)... 

Weldon et al, Evaluation of Metal Fuels for Use in Pyrotechnic Delays , Australian Weapons Research Establishment Technical Memorandum CPD 162 (1970) 37) R.H. Weldon et al,... 

Theoretical Analysis of Resonance Tube , The Singer Company, Final Report KD 72-82 (1972) 58) F.J. Valenta, The State of the Art of Navy Pyrotechnic Delays , Expls Pyrots (The Franklin Institute Research Laboratories) 5, Nos 11 12 (Nov-Dec 1972). See also Ref 144, pp 185—95. See also Some Factors Affecting Burning Rates and Variability of Tungsten and Manganese Delay Compositions , Ref 144, pp 157—83. See also Mil Spec for Tungsten Delay Compositions , MIL-T-23132A (June 1972) 59) C.F. Parrish et al, Radiation... 

W.C. Eller F J. Valenta, Temperature Compensate d Pyrotechnic Delays , USP 3851586... 

As both weaponry and the use of explosives for blasting developed, the need for a safe, reliable way to ignite these devices became obvious, and the concept of a pyrotechnic "delay" emerged. A variety of terms are used for materials that either ignite or provide a delay period between ignition of a device and the production of the main explosive or pyrotechnic effect. These include... 

Four pyrotechnic delay compositions given in 1961 edition of Ellern (Ref 44a) are listed in Vol 3 of Encycl, p D50. In regard to Exotic" Delay Mixtures, Dr Ellern remarks in the 1968 ed of his book (Ref 57, p 415), that these formulations were actually prepd and tested in his laboratory, but the limited investigation was not further pursued by him or by others. At the time of development of Nb(Cb)-Ta - Ba Chromate mixts, the delay mixts with Cr, Mo W(Tungsten) were classified in US. That is why Dr Ellern develops his own mixts which were not classified, although their components Niobium and Tantalum were rather expensive... 

Fuze, Hand Grenade. A pyrotechnic delay fuze initiated by release of a lever which in turn permits a striker to impinge on a primer. The output of the fuze is designed to ignite or detonate a filler of a hand grenade... 

Anon, "Engineering Design Handbook. Military Pyrotechnics Series. Part One. Theory and Application , US Army Materiel Command Pamphlet AMCP 706-185 (1967), pp 5-29 to 5-37 (Pyrotechnic delays) 5-37 to 5-40 (Ignition compns for gasless delay elements) 5-45 (Initiators, first fires, and star ter s) 5-45 to 5-46 (Pr ime ignition) ... 

PATR 2672 B. Werbel W.M. Stirrat, "Development of a Pyrotechnic Delay for the Vigilante 37-mm T324 HE Cartridge (April I960) (Conf)... 

R.A. Greenberg, "Development of Pyrotechnic Delay Trains for the T2049 and T2066 Rocket Fuzes , PATR 2365 (Oct 1956) (Conf)... 

On releasing the flare, the pyrotechnic delay (inside the fuze) was ignited. This fired the quickmatch, which in turn burned thru the flash tube and ignited the Black Powder charge in the tail. The pressure of the gases... 

In order to achieve the goals of pyrotechnic delay formulation, ingredients are chosen and formulated in an elegant way. The ingredients of a pyrotechnic delay formulation are (i) fuel (carbonaceous materials or inorganic substances) (ii) oxidizer (iii) binder and (iv) retardant, if required. 

Burning rate is of great significance in the case of pyrotechnic formulations as it is indicative of their functional performance. For example, characteristics such as luminosity, IR output etc. are closely related to the burning rate. Similarly, in a pyrotechnic delay formulation, the length of the delay column is decided in the light of the burning rate of the formulation. 

J.E. Rose R. Zimmer-Galler, Pyrotechnic Delay Composition Containing a Heavy Metal Soap , USP 3726730 (1973) CA 79, 7573... 

Weingarten, Pyrotechnic Delay Systems , in F.B. Pollard J.H. Arnold, Jr, Aerospace Ordnance Handbook , Prentice-Hall, Englewood Cliffs (1966), 282-84 table 285 11) K. 

Differential Thermal Analysis and Temperature Profile Analysis Studies on Pyrotechnic Delay Compositions , 1st ProcEurSympThermAnal, 446—47 (1976) CA 87,87214 (1977)... 

D.H. Brooks FJ Valenta, Pyrotechnic Delay Cutters for More Severe Acceleration and Temperature Environments , 10th ProcSymp-Expls Pyrots, Paper No 12 (1979) CA 92, 8485 (1980)... 

Figure 2.15 shows a schematic representation of the construction of a 12.7 mm multipurpose projectile with a pyrotechnic mixture (incendiary) and secondary explosive. Figure 2.16 schematically shows the construction of a hand grenade with a pyrotechnic delay composition. Bombs such as, for example, the MK 80 series, where approx. 45 % of the total mass is the explosive, usually contain pyrotechnic ( nose or tail ) fuses. 

Fig. 2.16 Schematic representation of the construction of a hand grenade with a pyrotechnical delay device.

Despite this study not being on the nanoscale, it does show the dramatic effect particle size has on combustion rate, since doubling the particle size causes the combustion rate to be more than halved. The Si / Pb304 mixture has found use as a pyrotechnic delay mixture (slow burning mixture used for timing in pyrotechnics) as its combustion rate is easily tailored. 

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