Fuel in a tank will not ignite, be it in a flamethrower or anywhere else, unless
there is an oxidizer present in the tank.. For ignition to occurr you need both
fuel and an oxidizer. Only when BOTH are present and in the right ratio, can a
reaction occurr. There are a few unstable fuels (like acetylene) that can
decompose on their own, but things like gasoline, fuel oil, and propane require
oxygen to burn. That's why you need an arrestor on an oxy-acetylene torch. When
you buy a new propane tank, it is purged before the first fill, to make sure all
the air (oxygen) is out, for this reason.
Also, flamethrower nozzle prevents any flames travelling back into the tank,
even if a reaction could occurr. The same goes for other kinds of torches.
The reason for pressurizing a flamethrower with nitrogen is so that there is no
oxidizer in the fuel tank. If TWA 800's fuel tank had been pressurized or
backfilled with nitrogen, there might not have been the crash, since there would
have been no fuel/oxidizer mix to explode.
Also, a stream of fuel only burns at the surface where oxygen is present, not
throughout the body of the stream. That's why you need a carb or injector
nozzle, to finely divide the fuel into tiny drops and increase the surface area,
so it will burn fast. Only by the intimate mixing of the fuel and oxidizer do
you get an explosion. Again, the ratio of fuel to air must be right.
-J
Edwin M. Dyer, III wrote:
> --- Geof Kaye <KAYE-RIVERCITY@webtv.net> wrote:
>
> > How does a flame thrower work? Other than squirting
> > a flammable
> > liquid-what keeps the liquid from ignition while in
> > the tanks? How is
> > the system pressurized? Anyone know of any sites on
> > the web?
>
> Speaking on WW2 flamethrowers, the German Flammnwerfer
> 41 and the Japanese Type 100, used nitrogen under
> pressure ( and in the case of the Type 100, compressed
> air ) as a means to propel the fuel out the flame gun.
> Ignition of the fuel took place in the flame gun,
> generally by a cartridge method. Other methods were
> used, such as flame ignition ( which had a flame lit
> at the muzzle which would fire the fuel upon using the
> flamethrower ) and electrical ignition, the later used
> on the US M1A1 ( this often failed, leaving the
> soldier to light the fuel jet with a match or burning
> paper ).
>
> As a rule, the force of the fuel leaving the flame
> projector was enough to prevent the flame travelling
> up the weapon to explode the tanks. Still, the
> flamethrowing teams were very vulnerable and become
> instant targets when spotted by the enemy. The
> Russians sought to solve this to a degree by making
> the flame projector of their ROKS-2 apparatus look
> like a service rifle.
>
> I know with German flamethrowing tanks, the rule was
> to douse the target in unlit fuel then fire a short
> burst of ignited fuel to touch off the fuel already
> sprayed.
>
> One of the more nasty tricks with flamethrowers is the
> ability to "bounce" the flame off walls and be able to
> hit targets around corners.
>
> Regards,
>
> Ed
>
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This archive was generated by hypermail 2b29 : Tue Jun 05 2001 - 23:18:38 PDT