john elder on tue 23 nov 99
I am trying to fire an old propane kiln that has caused problems for other
members of the co-op studio here. PROBLEM: it fires unevenly (top is about a
cone cooler), it uses alot of fuel and there is alot of flame coming out of
the chimney. The kilns interior specs are 49" wide, 29"deep and 561/2"h. The
stacking space is 32"wide, 27"deep and 47"h. The flue exit is 5 1/2"X 8" and
the chimney 9"X9" and 15' in height. The kiln has 4 burners (natural draw),I
don't know how many b.t.u.'s. The co-op member who has fired the kiln in the
past would fire it by leaving the primary air open and the gas valves at the
burners open and control the gas at the main value at the tank, using
between 1 1/2 and 41/2 lbs pressure and use the damper to control the
reduction. ANY suggestions or ideas would be appreciated.
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Pat Lindemann on wed 24 nov 99
Have you considered how the kiln is stacked and the distance of the shelves fro
Just an idea...
Pat Lindemann
Pierre, SD
--
On Tue, 23 Nov 1999 10:49:43 john elder wrote:
>----------------------------Original message----------------------------
>I am trying to fire an old propane kiln that has caused problems for other
>members of the co-op studio here. PROBLEM: it fires unevenly (top is about a
>cone cooler), it uses alot of fuel and there is alot of flame coming out of
>the chimney. The kilns interior specs are 49" wide, 29"deep and 561/2"h. The
>stacking space is 32"wide, 27"deep and 47"h. The flue exit is 5 1/2"X 8" and
>the chimney 9"X9" and 15' in height. The kiln has 4 burners (natural draw),I
>don't know how many b.t.u.'s. The co-op member who has fired the kiln in the
>past would fire it by leaving the primary air open and the gas valves at the
>burners open and control the gas at the main value at the tank, using
>between 1 1/2 and 41/2 lbs pressure and use the damper to control the
>reduction. ANY suggestions or ideas would be appreciated.
>
>______________________________________________________
>Get Your Private, Free Email at http://www.hotmail.com
>
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Andrew Buck on thu 25 nov 99
John,
It sounds like you have a downdraft kiln there but you do not mention a
bag wall or if the flame comes into the kiln from the bottom or through
the walls. That information would be helpful in tuning the kiln, but, I
think the major problem you are having is that the gas pressure is way too
high. If you are seeing flames at the top of a fifteen foot tall chimney
then a lot of gas is shooting right through the kiln unburned. I would
suggest using a lower gas pressure, in the inches water column range as
opposed to the pounds per inch, and increasing the orifice size in the
burners.
Andy Buck
Raincreek Pottery
Port Orchard, Washington
On Tue, 23 Nov 1999, john elder wrote:
> ----------------------------Original message----------------------------
> I am trying to fire an old propane kiln that has caused problems for other
> members of the co-op studio here. PROBLEM: it fires unevenly (top is about a
> cone cooler), it uses alot of fuel and there is alot of flame coming out of
> the chimney. The kilns interior specs are 49" wide, 29"deep and 561/2"h. The
> stacking space is 32"wide, 27"deep and 47"h. The flue exit is 5 1/2"X 8" and
> the chimney 9"X9" and 15' in height. The kiln has 4 burners (natural draw),I
> don't know how many b.t.u.'s. The co-op member who has fired the kiln in the
> past would fire it by leaving the primary air open and the gas valves at the
> burners open and control the gas at the main value at the tank, using
> between 1 1/2 and 41/2 lbs pressure and use the damper to control the
> reduction. ANY suggestions or ideas would be appreciated.
David Hendley on fri 26 nov 99
A couple of thoughts:
You didn't say if this kiln has a bag wall.
If it does, make the bag wall higher, to direct the
heat upwards.
It also sounds like it is reducing too much, what with lots
of flames coming out of a chimney that tall. Is it getting
secondary air?
--
David Hendley
Maydelle, Texas
hendley@tyler.net
http://www.farmpots.com/
----- Original Message -----
From: john elder
To:
Sent: Tuesday, November 23, 1999 9:49 AM
Subject: NEED HELP TO FIRE KILN
| ----------------------------Original message----------------------------
| I am trying to fire an old propane kiln that has caused problems for other
| members of the co-op studio here. PROBLEM: it fires unevenly (top is about
a
| cone cooler), it uses alot of fuel and there is alot of flame coming out
of
| the chimney. The kilns interior specs are 49" wide, 29"deep and 561/2"h.
The
| stacking space is 32"wide, 27"deep and 47"h. The flue exit is 5 1/2"X 8"
and
| the chimney 9"X9" and 15' in height. The kiln has 4 burners (natural
draw),I
| don't know how many b.t.u.'s. The co-op member who has fired the kiln in
the
| past would fire it by leaving the primary air open and the gas valves at
the
| burners open and control the gas at the main value at the tank, using
| between 1 1/2 and 41/2 lbs pressure and use the damper to control the
| reduction. ANY suggestions or ideas would be appreciated.
|
| ______________________________________________________
| Get Your Private, Free Email at http://www.hotmail.com
Jung, Don on mon 29 nov 99
John,
This might come a tad late, since I don't get through the clayart mail too
much. I tend to agree with Andrew but you may want to look into getting a
flame retention nozzle for the burners. There was a thread on these not
long ago. They'll help mix and pull in more primary air to get a better
burn and max heat. This should reduce the amount of gas used and pressure
needed.
You may also try to find out if there is enough secondary air to get an
efficient burn. The burner port should have plenty of room for the burner.
I use 1/2 to 1" all around and about 1" away. See if you can get the kiln
firing in oxidation. When you put a stick in the kiln through the peep,
it'll burn with a flame. (otherwise it'll char and burst into flames only
when you pull it out... reduction) Use the top or middle peep for this
test... I'm assuming your burners are on the bottom somewhere. Once you get
oxidation, gradually push in the damper to reduce the pull of secondary air
and you should begin to get reduction. (do the stick test again) Just
before getting reduction... is neutral, where you get maximum burn/heat. I
go by having reduction in the top and middle peeps and oxidizing in the
bottom to get a nice light to moderate reduction. There should not be much
flame out the top of the chimney in oxidation, neutral or even light
reduction as most of the gas should be burnt already. Well, at least I
usually don't see any flame coming out the top in a gas firing (with light
reduction).
Also, if you can find out what size orifice you have on those burners, you
can figure out the btus for the amount of gas pressure you use. Try
measuring with different drill bits. Olsen's book has a chart to figure it
out.
Keep notes and keep learning
Don Jung
> -----Original Message-----
>
> Date: Thu, 25 Nov 1999 10:25:14 EST
> From: Andrew Buck
> Subject: Re: NEED HELP TO FIRE KILN
>
> ----------------------------Original
> message----------------------------
> John,
>
> It sounds like you have a downdraft kiln there but you do not
> mention a
> bag wall or if the flame comes into the kiln from the bottom
> or through
> the walls. That information would be helpful in tuning the
> kiln, but, I
> think the major problem you are having is that the gas
> pressure is way too
> high. If you are seeing flames at the top of a fifteen foot
> tall chimney
> then a lot of gas is shooting right through the kiln
> unburned. I would
> suggest using a lower gas pressure, in the inches water
> column range as
> opposed to the pounds per inch, and increasing the orifice size in the
> burners.
>
> Andy Buck
> Raincreek Pottery
> Port Orchard, Washington
>
> On Tue, 23 Nov 1999, john elder wrote:
>
> > ----------------------------Original
> message----------------------------
> > I am trying to fire an old propane kiln that has caused
> problems for other
> > members of the co-op studio here. PROBLEM: it fires
> unevenly (top is about a
> > cone cooler), it uses alot of fuel and there is alot of
> flame coming out of
> > the chimney. The kilns interior specs are 49" wide, 29"deep
> and 561/2"h. The
> > stacking space is 32"wide, 27"deep and 47"h. The flue exit
> is 5 1/2"X 8" and
> > the chimney 9"X9" and 15' in height. The kiln has 4 burners
> (natural draw),I
> > don't know how many b.t.u.'s. The co-op member who has
> fired the kiln in the
> > past would fire it by leaving the primary air open and the
> gas valves at the
> > burners open and control the gas at the main value at the
> tank, using
> > between 1 1/2 and 41/2 lbs pressure and use the damper to
> control the
> > reduction. ANY suggestions or ideas would be appreciated.
>
| |
|
