Propagation of flame

Equipment described as explosion-proof is equipment installed in enclosures that will withstand internal explosions and also prevent the propagation of flame to the external atmosphere. As the gases generated by the explosion expand, they must be cooled before reaching the surrounding atmosphere. 

Where there is reasonable potential for ignition of a vapor mix in the flammable range, means shall be provided to stop the propagation of flame through the vapor collection system. The means chosen shall be appropriate for the conditions under which they will be used. 

Flammable Limits The minimum and maximum concentration of fuel vapor or gas in a fuel vapor or gas/gaseous oxidant mixture (usually expressed in percent hy volume) defining the concentration range (flammable or explosive range) over which propagation of flame will occur on contact with an ignition source. See also Lower Flammable Limit and Upper Flammable Limit. 

Maly, R. and Vogel, M., Initiation and propagation of flame fronts in lean CH4-air mixtures by the three modes of the ignition spark, Proc. Combust. Inst., 17, 821,1979. 

Mason, W. and Wheeler, R.V., The propagation of flame in mixtures of methane and air. Part 11. Vertical propagation, Journal of the Chemical Society Transactions, 117, 1227-1237, 1920. 

Gardner, W.E. and Pugh, A., The propagation of flame in hydrogen-oxygen mixtures, Trans. Faraday Soc., 35 283, 1939. 

Flame arresters are fitted in the vent lines of equipment that contains flammable material to prevent the propagation of flame through the vents. Various types of proprietary flame arresters are used. In general, they work on the principle of providing a heat sink, usually expanded metal grids or plates, to dissipate the heat of the flame. Flame arrestors and their applications are discussed by Rogowski (1980), Howard (1992) and Mendoza et al. (1988). 

Lower Explosive Limit (LEL) - The minimum concentration of combustible gas or vapor in air below which propagation of flame does not occur on contact with an ignition source. 

Fig B. Propagation of Flame Reaction Zone in Rough Pipes... 

Kniga I. Teplovoi Vzryv i Rasprostraneniye Plameni v Gazakh (Thermal Explosion and Propagation of Flames in Gases)... 

CA 42, 5229(1948)(Theory of propagation of flame. States conditions in an expl chem reaction necesssry for propagation of the flame at a const rate. Calcs this rate for a definite relationship between diffusion and heat conductance. Evaluates the effect of chain reactions on the propagation of the flame) 4) B. Karlovitz, JChemPhys 19, 541-46(1951) Sc CA 45, 9341 (1951)(Theory of turbulent flames) 5) G. Klein, Phil-TransRoySocLondon 249, 389—415 (1957)... 

The propagation of flame from grain to grain is caused by an emission of hot molten potassium salts projected from one grain to another as the powder burns. 

Investigation of the limits of flammability and of self-propagation of flame through a gaseous explosive medium became one of the main subjects of research on the combustion of gaseous mixtures. 

E.Jones, JSCI 69,206-12<1950)(Umits for the propagation of flame in acetaldehyde-oxygen-nitrogen mixtures) e)J. d Ans et al, AngChem 66,633-5(1954) CA 49,10832 (1955) (Peroxide derivatives of acetaldehyde, prepd by treating AcH with peroxy acids. All the compds are highly explosive)(16 references)... 

W., Theory of Propagation of Flames, Parts I, II, III, Third Symposium on Combustion, Flame, and Explosion Phenomena, pp. 121-40, Williams Wilkins, Baltimore, 1949. 

Over the last 20 years chemical kinetics, and especially the theory of chain reactions, have achieved major successes. A theory of ignition of heated explosive mixtures has been created. However, attempts to directly explain the propagation of flame as the diffusion of active centers, or to explain the limits of propagation by the conditions of chain breaking fail to yield positive results. 

A. G. White also calculated the flame temp, which ranged from 1610° to 1840°. He also studied the propagation of flame in mixtures of hydrogen and ammonia. 

The limits for the propagation of flame by twelve organic vapours when mixed with air in glass tubes 5 0 cm. in diameter, determined, unless otherwise stated, at approximately 18° C., are given on p. 100.2... 

In 1882 Mallard and Le Chatelier6 gave the results of an investigation into the rate of propagation of flame in mixtures of air and a combustible... 

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