Flame traps

In the vent pipes of storage tanks containing a flammable mixture of vapor and air (Section 5.4.1). Such flame traps should be inspected regularly and cleaned if necessary. Section 5.3 a described how a tank was sucked in because the flame arrestors on all three vents had not been cleaned for two years. 

Cubbage, P. A. 1959. Flame Traps for Use with Town Gas/Air Mixtures. Gas Council Research Communication GC 63. The Gas Council, London, England. 

Cubbage, P. A. 1963. The Protection by Flame Traps of Pipes Conveying Combustible Mixtures. IChemE Symposium Series No. 15, pp. 29-34. Institution of Chemical Engineers, Rugby, England. 

Kletz. T. A. 1982. A Flame Trap Assembly for Use with High Melting Point Materials. Plant/Operations Progress, 1(4), 252-254. 

Flame Trap Another name for a flame arrester, commonly used in the United Kingdom. 

In certain applications a flame trap may be required, and further guidance is given in HSE publication HS(G)11,... 

Flame Arrestors and Explosion Reliefs. The flame trap is constructed of strips of corrugated and flat steel ribbon wound in a spiral. It breaks up a flame in the very small passages between the corrugations where the flame is quenched and extinguished. 

A flame trap is employed where premixed air and gas is used in combustion equipment and prevents the flame passing upstream into the pipe system. Flame traps should be situated as near as possible to the gas burner. This is so that the flame does not have a long pipe mn in which it might accelerate to such a speed as to form a detonation wave and make the trap useless. 

Thermocouple elements can be incorporated into the flame trap so that a flame that has lit back to the flame trap element and continued to burn there without being quenched can be detected. This sensor can be used to close an upstream safety shut-off valve. Flame traps will be the cause of a significant pressure drop for which allowances must be made in low-pressure systems. 

Procedures Startup, Normal, Shutdown, Ditches Flame Traps, Reactions, Exposures,... 

Figure 8-3. Drainage Trench Flame Trap Designs...

The action of safety sheaths has been widely investigated and it seems probable that the finely dispersed material of the sheath functions as a flame trap in the firedamp mixt, and prevents propagation of any flame or ignition (Ref 34a, p 22)... 

Hatches Vents Characteristics Flame traps, reactions, exposures and solids Discharge, dispersion, radiation and mists Sludges, residues and fouling materials... 

The flare must be equipped with diverse safety systems to prevent flashback of the flame (e.g., water-immersion bath, flame traps, acceleration path as dynamic flashback protector). 

If pressure discharge of tank wagons or the clearance of pipelines of contaminated solvent with inert gas is routinely practised, there is a risk that droplets of solvent will be caught by flame traps or gauzes on the tank vent. As the solvent evaporates any residue will be left behind, restricting or blocking the vent. 

Tank vents need to be inspected regularly for blockage or failure of gauzes or flame traps due to corrosion. Much more frequent inspection is needed when liquids with certain properties are stored ... 

Fire is propagated by means of a free radical chain reaction and so anything which will interrupt this chain will cause the fire to die. The halons family of chemicals, which are chloro-, bromo-, fluoro-hydrocarbons, are very efficient at this. Spreading the heat over large surface areas, as in flame traps or with the powder of a dry powder extinguisher, also effectively removes the free radicals and hence results in a suppression of the fire. 

Water scrubbers—The primary purpose of water scrubbers is to perform evaporative cooling on exhaust gases and to act as a flame trap. Although water scrubbers are able to reduce soot by 10% to 30%, there are no reductions in gaseous emissions. As a control technology, their applications are limited. 

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