[TheForge] Burners

[Bruce Freeman]

Kenny,
 
I'm probably not the best person to answer this.  I think I know the
answer and will tell you what I believe to be correct:
 
There are two things that can be called the "flare" on a burner.  The
"bell" constriction where the gas is introduced and the flare at the
end, to hold the flame.  The bell constriction is really to induce a
venturi.  It is not absolutely necessary (none is used on a Bunsen
burner) but may improve the air aspiration in "atmospheric" burners
(i.e., those without air blowers).
 
The "true" flare is at the end of some burners, at the flame, and serve
to reduce the velocity of the mixed gases, so as not to blow out the
flame.  There are other devices that work as well - a flare is not the
only possible "flame-holder."  Furthermore, a flame holder is not
necessary on a burner directed into a forge, since the mixed gases will
reignite on the hot surface of the forge.  Mineral wool is especially
good at reigniting the burning gases.
 
I understand the the bent tube is a mixing device.  From what I've
observed and read, here and elsewhere, efficient mixing of gas and air
is a "recent" improvement in burner design.  There are lots of ways to
mix gases.  Atmospheric burners do it in the venturi by aspiration - the
fuel gas molecules literally collide with the air molecules.  In
principle, a blower design without a mixer could have a nice clean
stream of fuel gas in the middle, and a nice clean stream of air on the
outside, with minimal mixing between.  No good.  
 
Hope this helps.
 
Bruce
NJ

>>> phat@cavenet.com 3/7/2004 11:38:36 PM >>>

I am curious about the physics of two different types of burners. The 
burners that are in the
ABANA / Gunter forge have no adj. carb, the tube has no flare, but they

do have an oblique
angle of 135*.
Why does the one type need a flare (to burn correctly) and not the 
other? One needs carbonation,
one not. I have been reading the burner book and have found (so far 
anyway) no reference to these
bent tube burners.

Thanks All.
Kenny O