[TheForge] Gas Forge "Chuffs"

Wed Jan 29 14:02:13 2003

Scott,

If all the other forges work well at this pressure and yours does not, =
then I'd suspect it is the orifice, or just possibly the regulator or =
gauge.  You don't clarify what sort of burners you have other than =
atmospheric (non-blown).  In ones NJBA made we drilled a brass plug as the =
orifice.  If there were a burr in the hole, that could impede the blast of =
propane, especially at low pressure, and hence adversely affect the mixing =
with air.  That's what sounds like is happening, so you might get a hand =
lens and a bright light and have a look at the orifice.  You could run a =
cat whisker (fine stiff wire) through the orifice to displace any crud or =
burrs that might be present.  Judging from the pressure you're using, I'd =
suspect  your orifice is pretty small, like a #70 drill or so.  These can =
plug fairly easily.

However, possibly your regulator is not giving you the pressure you think. =
 The gauge would be the real problem.  If your pressure is very near the =
bottom "peg" of the regulator, could it possibly be, say, ~5 psi LESS than =
the gauge reads?  If so, you've basically throttled off the burner.

Bruce
NJ

>>> [email protected] 01/28/03 11:42PM >>>
Greetings,
	I participated in a gas forge construction workshop this weekend, =
in which=20
we build 14 new double burner atmospheric gas forges.  They are made out =
of=20
10" thin wall pipe, with two non-blown burners coming in horizontally =
near=20
the top of the forge.
	Got mine home and fired it up.  Runs great at 20lbs gas, but when =
I reduce=20
the psi down to 5 or 7psi the combustion "chuffs" (surges) and does not=20
burn completely.  There is a massive amount of blue flame coming out =
the=20
front, no matter how far I open or close the air gates (adjustable disks =
on=20
the end of the burner pipes).
	I have seen a number of these exact forges run well, so I don't =
think it's=20
the design.  However, with any mass construction effort there is bound =
to=20
be minor differences.  For instance, most of the forges built had the=20
burner pipes running slightly "down hill" into the forge, where mine =
run=20
slightly "up hill".
	Any suggestions on the combustion problem?

Thanks,
Scott

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