jcjm on thu 2 mar 00
I have another question for those who could help.
I fire a very unconventional kiln as my fire power is quite low. I'm only
firing with a modified weed burner. By opening the orifice more will I
really get more BTU's or am I just letting out more gas? I'm afraid I
won't be able to regulate the amount of gas coming out of the burner if I
enlarge the orifice. Do I really get a bigger hotter flame? Wouldn't I
need an extra supply of air to assist the combustion? Is there a ratio
between the orifice and the tube of the burner? Am I asking for too much?
Thank you again for any help.
j-m
Marc Ward on fri 3 mar 00
<< Am I asking for too much? >>
Probably. You pretty much guessed that expanding the orifice won't
necessarily increase BTU's if you can't provide more primary and secondary
air. Many times expanding the orifice will make matters worse.
Most weed burners don't have regulators, so you're working with a tiny
orifice and very high tank pressure. The BTU output is continually dropping
because you are using up the fuel. This is akin to driving your car without a
gas pedal. You go 120 miles an hour when the tank is full and begin slowing
down as you use up the gasoline. Weed burners are very prone to causing tank
freeze up because they have a very high (and unregulated) output that
immediately begins over-cooling usually small raku tanks.
<between the orifice and the tube of the burner?>>
Yes, there is a ratio between flame tube size and orifice size at certain
pressures, but it isn't a set ratio, especially if you greatly change gas
pressure. OK, I'm getting ready to sound like a smart ass, but here goes....
when you bought your weed burner, I bet the package didn't say anything about
firing kilns with your new burner. They're for burning.....you guessed
it....weeds.
Marc Ward
Ward Burner Systems
PO Box 1086
Dandridge, TN 37725
865.397-2914 Voice
865.397-1253 Fax
wardburner@aol.com Email
wardburner.com Online Catalog
Louis Katz on mon 13 mar 00
Simply,
You should be able to enlarge the orifice until just before your kiln starts
to reduce. After that you will start to get a decrease in efficiency. If you
continue even further your reduction will be so strong that you will get less
heat rise than before you started to enlarge them. If your propane tank is
freezing up already bigger orifices won't help much.
Best Bet? Build a forced air burner and put a regulator on your gas, use
large gas tanks. Spend money to save money, time, frustration etc.. Consult
with Mark Ward or another reputable burner outfit.
Louis
jcjm wrote:
> ----------------------------Original message----------------------------
> I have another question for those who could help.
> I fire a very unconventional kiln as my fire power is quite low. I'm only
> firing with a modified weed burner. By opening the orifice more will I
> really get more BTU's or am I just letting out more gas? I'm afraid I
> won't be able to regulate the amount of gas coming out of the burner if I
> enlarge the orifice. Do I really get a bigger hotter flame? Wouldn't I
> need an extra supply of air to assist the combustion? Is there a ratio
> between the orifice and the tube of the burner? Am I asking for too much?
> Thank you again for any help.
> j-m
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