Ray Carlton on sat 29 nov 97
hi all...a question for the kiln experts
My new 65 cuft ifb d/draft kiln [the subject of two posts already this
month] is still causing me headaches. I can't get enough gas pressure at
the the kiln.
the 6 burners are 1.5" diam long venturies connected by 1/2" pipe to a 3/4"
halo.
the halo is connected by 1/2" pipe to 3/4" pipe running about 10 yards to
two 100 gallon propane tanks. the primary regulator [on the bottles] is set
at 25 psi. The secondary regulator [at the kiln] won't go over about 3 psi
with all burners full on. The pressure at the bottles is reading 25 ...the
pressure at the kiln is 3 psi max what is happening?? No leaks are
detectable. I can get the pressure to rise at the kiln to 25 psi with the
burners off. Why can't I do it while the burners are on???
any ideas would be greatfully received
cheers
raycarlt@valylink.net.au
Ray Carlton
McMahons Creek Victoria Australia 3799
Michelle McCurdy on sun 30 nov 97
I know this may be a dumb question but..... Are these propane orifices?? I
had a friend that couldn't get her kiln to temperature and it turned out she
was using natural gas orifices. Actually too much propane was getting in the
kiln and the temp can't rise that way.
David Woodin on sun 30 nov 97
The best help you can get is from Mark Ward 423-397-2914, or email,
wardburner@aol.com. He will need more detailed information, such as how many
BTU will your burner put out and at what pressure, what make is it. You
will not get 25 psi output at the burners themselves, due to pressure drop in
the line, size of line, length, but you can get the pressure you will need by
possibily increasing the output of the first stage regulator, provided that
the line size is large enough to get the volume of gas you need at the
burners. As a rough guide you will need between 10,000 and 16,000 BTU per
cubic foot for a 9 to 12 hour cone 10 firing, this means 640,000 to
1,024,000 BTU total divided by the 6 burners, or 106,667 to 1,706,667 per
burner. This will be the ballpark figure that tells you if the burners are
even large enough for your kiln. Mark Ward will be very helpful to you.
Good luck
David
Daphne Zeitz on mon 1 dec 97
At 05:18 PM 11/30/97 EST, you wrote:
>----------------------------Original message----------------------------
> I know this may be a dumb question but..... Are these propane orifices?? I
>had a friend that couldn't get her kiln to temperature and it turned out she
>was using natural gas orifices. Actually too much propane was getting in the
>kiln and the temp can't rise that way.
>
>Michelle,
My portable updraft propane kiln had the same problem when it was new. It
was hard to get it hot enough inside and there was lots of flame shooting
out of the top. My husband replaced the tips with blank ones which he
drilled with smaller orifices. This completely rectified the problem.
Good luck, Daphne
Daphne Zeitz
Michelle McCurdy on mon 1 dec 97
Actually I thought about this more. If they are natural gas
burners(orifices) maybe when the valves are open, and the orifice is too big
then too much gas is getting into the kiln and the pressure cannot stay
where you want it . Just a thought.
jjcat on mon 1 dec 97
Propane has smaller orifices than natural gas almost half, smaller.
joe,
kiln-ray
At 05:18 PM 11/30/97 EST, you wrote:
>----------------------------Original message----------------------------
> I know this may be a dumb question but..... Are these propane orifices?? I
>had a friend that couldn't get her kiln to temperature and it turned out she
>was using natural gas orifices. Actually too much propane was getting in the
>kiln and the temp can't rise that way.
>
>
Gavin Stairs on mon 1 dec 97
Hi Ray,
The problem is flow resistance in the line, either from restrictions or too
small a pipe diameter. I don't know if 1/2" pipe is big enough or not.
The first thing is to check for obstructions, such as something in the
pipe, or too many elbows and valves, or a small valve right at the tank
end, or a valve that won't open properly. You may have to take the pipes
apart in order to check this. Your local gas supplier can advise you on
sizing the line: they can tell you if your 1/2" line is big enough. I
suspect it is not. It's really surpising how much gas you need to push
through to torch a kiln.
Gavin
At 09:41 AM 29/11/97 EST, you wrote:
>----------------------------Original message----------------------------
>hi all...a question for the kiln experts
>My new 65 cuft ifb d/draft kiln [the subject of two posts already this
>month] is still causing me headaches. I can't get enough gas pressure at
>the the kiln.
>the 6 burners are 1.5" diam long venturies connected by 1/2" pipe to a 3/4"
>halo.
>the halo is connected by 1/2" pipe to 3/4" pipe running about 10 yards to
>two 100 gallon propane tanks. the primary regulator [on the bottles] is set
>at 25 psi. The secondary regulator [at the kiln] won't go over about 3 psi
>with all burners full on. The pressure at the bottles is reading 25 ...the
>pressure at the kiln is 3 psi max what is happening?? No leaks are
>detectable. I can get the pressure to rise at the kiln to 25 psi with the
>burners off. Why can't I do it while the burners are on???
>
>any ideas would be greatfully received
>
>cheers
>raycarlt@valylink.net.au
>
>
>
>Ray Carlton
>McMahons Creek Victoria Australia 3799
>
>
stairs@echo-on.net
http://isis.physics.utoronto.ca/
416 530 0419 (home) 416 978 2735 (work)
Toronto, Ontario, Canada
Ray Carlton on tue 2 dec 97
thanks gavin....you hit the nail on the head. We had 1/4 feed pipes onto
the primary regulator far too small
I would like to thank all who have posted replies to my queries on the new
kiln. I have fired it a few times now and the second glaze firing [as yet
unopened] was on saturday. I am beginning to understand a bit more about it
now. It seems a bit silly that I have been a professional potter for some
20 years and know so little about kilns. I have always used a city slickers
fibre lined stainless steel job and it is now almost dead...
thanks again
At 02:38 01/12/97 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Ray,
>
>The problem is flow resistance in the line, either from restrictions or too
>small a pipe diameter. I don't know if 1/2" pipe is big enough or not.
>The first thing is to check for obstructions, such as something in the
>pipe, or too many elbows and valves, or a small valve right at the tank
>end, or a valve that won't open properly. You may have to take the pipes
>apart in order to check this. Your local gas supplier can advise you on
>sizing the line: they can tell you if your 1/2" line is big enough. I
>suspect it is not. It's really surpising how much gas you need to push
>through to torch a kiln.
>
>Gavin
>
>At 09:41 AM 29/11/97 EST, you wrote:
>>----------------------------Original message----------------------------
>>hi all...a question for the kiln experts
>>My new 65 cuft ifb d/draft kiln [the subject of two posts already this
>>month] is still causing me headaches. I can't get enough gas pressure at
>>the the kiln.
>>the 6 burners are 1.5" diam long venturies connected by 1/2" pipe to a 3/4"
>>halo.
>>the halo is connected by 1/2" pipe to 3/4" pipe running about 10 yards to
>>two 100 gallon propane tanks. the primary regulator [on the bottles] is set
>>at 25 psi. The secondary regulator [at the kiln] won't go over about 3 psi
>>with all burners full on. The pressure at the bottles is reading 25 ...the
>>pressure at the kiln is 3 psi max what is happening?? No leaks are
>>detectable. I can get the pressure to rise at the kiln to 25 psi with the
>>burners off. Why can't I do it while the burners are on???
>>
>>any ideas would be greatfully received
>>
>>cheers
>>raycarlt@valylink.net.au
>>
>>
>>
>>Ray Carlton
>>McMahons Creek Victoria Australia 3799
>>
>>
>stairs@echo-on.net
>http://isis.physics.utoronto.ca/
>416 530 0419 (home) 416 978 2735 (work)
>Toronto, Ontario, Canada
>
>
raycarlt@valylink.net.au
Ray Carlton
McMahons Creek Victoria Australia 3799
Ric Swenson on tue 2 dec 97
If I remember correctly....and who knows if THAT could happen ??
........................the flow in a pipe...air....for ventilation.......or
gas...... or what ever...is constricted by half for EACH 90 degree bend....
Try to use NO bends......or use....45 degree bends...or reduce 90's to a
minimum and you might help the situation....or you might HAVE to increase
SIZE, (ie... Diameter...) of the pipe......
HTH
Ric
>----------------------------Original message----------------------------
>Hi Ray,
>
>The problem is flow resistance in the line, either from restrictions or too
>small a pipe diameter. I don't know if 1/2" pipe is big enough or not.
>The first thing is to check for obstructions, such as something in the
>pipe, or too many elbows and valves, or a small valve right at the tank
>end, or a valve that won't open properly. You may have to take the pipes
>apart in order to check this. Your local gas supplier can advise you on
>sizing the line: they can tell you if your 1/2" line is big enough. I
>suspect it is not. It's really surpising how much gas you need to push
>through to torch a kiln.
>
>Gavin
>
>At 09:41 AM 29/11/97 EST, you wrote:
>>----------------------------Original message----------------------------
>>hi all...a question for the kiln experts
>>My new 65 cuft ifb d/draft kiln [the subject of two posts already this
>>month] is still causing me headaches. I can't get enough gas pressure at
>>the the kiln.
>>the 6 burners are 1.5" diam long venturies connected by 1/2" pipe to a 3/4"
>>halo.
>>the halo is connected by 1/2" pipe to 3/4" pipe running about 10 yards to
>>two 100 gallon propane tanks. the primary regulator [on the bottles] is set
>>at 25 psi. The secondary regulator [at the kiln] won't go over about 3 psi
>>with all burners full on. The pressure at the bottles is reading 25 ...the
>>pressure at the kiln is 3 psi max what is happening?? No leaks are
>>detectable. I can get the pressure to rise at the kiln to 25 psi with the
>>burners off. Why can't I do it while the burners are on???
>>
>>any ideas would be greatfully received
>>
>>cheers
>>raycarlt@valylink.net.au
>>
>>
>>
>>Ray Carlton
>>McMahons Creek Victoria Australia 3799
>>
>>
>stairs@echo-on.net
>http://isis.physics.utoronto.ca/
>416 530 0419 (home) 416 978 2735 (work)
>Toronto, Ontario, Canada
#####################################
From: Ric Swenson, ( home ) : P.O. Box 494,
North Bennington, VT 05257 - 0494 U.S.A
home telephone ( 802 ) 447 - 4744
( work ) : Bennington College, Route 67 - A
Bennington, Vermont 05201 - 6001
( 802 ) 440 - 4621 ( fax 440 - 4582 )
email: rswenson@bennington.edu
#####################################
" If you want to teach a bear to dance,
you should be prepared to dance
until the bear gets tired. "
..... Russian proverb
--------------------
"Idealism increases in direct proportion
to one's distance from the problem"
......John Galsworthy
jjcat on tue 2 dec 97
1/2" pipe is not large enough. Should go to 3/4". Every fitting and full
open valve should be 3/4", right up to the burner tip. Check size of orifice
at burner tip. Should not be larger than .23 inches, measure with caliper.
What is your BTU output of each burner. Are you sure you don't have to many
burners for that size kiln. You may want to consider 4.
kilnray
At 02:38 PM 12/1/97 EST, you wrote:
>----------------------------Original message----------------------------
>Hi Ray,
>
>The problem is flow resistance in the line, either from restrictions or too
>small a pipe diameter. I don't know if 1/2" pipe is big enough or not.
>The first thing is to check for obstructions, such as something in the
>pipe, or too many elbows and valves, or a small valve right at the tank
>end, or a valve that won't open properly. You may have to take the pipes
>apart in order to check this. Your local gas supplier can advise you on
>sizing the line: they can tell you if your 1/2" line is big enough. I
>suspect it is not. It's really surpising how much gas you need to push
>through to torch a kiln.
>
>Gavin
>
>At 09:41 AM 29/11/97 EST, you wrote:
>>----------------------------Original message----------------------------
>>hi all...a question for the kiln experts
>>My new 65 cuft ifb d/draft kiln [the subject of two posts already this
>>month] is still causing me headaches. I can't get enough gas pressure at
>>the the kiln.
>>the 6 burners are 1.5" diam long venturies connected by 1/2" pipe to a 3/4"
>>halo.
>>the halo is connected by 1/2" pipe to 3/4" pipe running about 10 yards to
>>two 100 gallon propane tanks. the primary regulator [on the bottles] is set
>>at 25 psi. The secondary regulator [at the kiln] won't go over about 3 psi
>>with all burners full on. The pressure at the bottles is reading 25 ...the
>>pressure at the kiln is 3 psi max what is happening?? No leaks are
>>detectable. I can get the pressure to rise at the kiln to 25 psi with the
>>burners off. Why can't I do it while the burners are on???
>>
>>any ideas would be greatfully received
>>
>>cheers
>>raycarlt@valylink.net.au
>>
>>
>>
>>Ray Carlton
>>McMahons Creek Victoria Australia 3799
>>
>>
>stairs@echo-on.net
>http://isis.physics.utoronto.ca/
>416 530 0419 (home) 416 978 2735 (work)
>Toronto, Ontario, Canada
>
>
Mark Issenberg on tue 2 dec 97
Hi R ay I used one and half galvanised pipe for my gas line . I
rented the pipe cutter . My line is around 30 feet long .It was actually
fun cutting and putting together this line . I have no problem with not
enough gas. Mark in Miami
Arturo M DeVitalis on wed 3 dec 97
Just an AMEN to eliminating as much as possible the 90 degree bends.
Also remember to bring the gas from the meter in as large a diameter pipe
as possible, and make it into a "manifold" , and from that manifold go as
closeup to the burners with as large a diameter as possible before
reducing down to the required size.
After remodeling the meter-to-burners setup I had more natural gas than I
could ever use...before that it was nip and tuck.
Vince Pitelka on wed 3 dec 97
>hi all...a question for the kiln experts
>My new 65 cuft ifb d/draft kiln [the subject of two posts already this
>month] is still causing me headaches. I can't get enough gas pressure at
>the the kiln.
>the 6 burners are 1.5" diam long venturies connected by 1/2" pipe to a 3/4"
>halo.
>the halo is connected by 1/2" pipe to 3/4" pipe running about 10 yards to
>two 100 gallon propane tanks. the primary regulator [on the bottles] is set
>at 25 psi. The secondary regulator [at the kiln] won't go over about 3 psi
>with all burners full on. The pressure at the bottles is reading 25 ...the
>pressure at the kiln is 3 psi max what is happening?? No leaks are
>detectable. I can get the pressure to rise at the kiln to 25 psi with the
>burners off. Why can't I do it while the burners are on???
Ray -
You are getting a bunch of conflicting advice here, including some which I
think is very misleading. I do not think the problem is in the pipe at all.
At the Craft Center we have a 60 cubic foot salt kiln constructed entirely
from high-alumina hardbrick, which REALLY soak up the heat. We have a
single regulator behind the kiln, and from there on all the plumbing is 1/2"
black iron pipe. The burners are four huge 3" I.D. GACO venturis, operating
at a maximum of 15 lbs. propane, with orifices 3/32" diameter, and the kiln
fires like a dream in about ten hours.
I think your problem is in one of the regulators, most likely the one at the
kiln. First, make absolutely sure that both regulators are installed
properly, with the gauge measuring the pressure on the low-pressure side of
the regulator. All regulators have stamped on the housing next to the pipe
hookups the word "in" or "out" or an arrow, clearly indicating the direction
of gas flow. Make sure yours are installed properly, and that the gauge is
reading the pressure on the output side. Oxy-acetylene regulators are
different, because they have two gauges, which indicate pressure on both
sides of the regulator, but propane regulators usually only have a single
gauge. If the regulators are installed properly, then the tank regulator
gauge is indicating the pressure between it and the kiln regulator, and the
kiln regulator gauge is indicating the pressure between it and the burners.
If the gauge on the tank regulator is consistently reading 25 psi, and if
that does not change when the burners are turned up full, and if the gauge
on the kiln regulator never reads over 3 psi, then the problem has to be in
the kiln regulator.
I would make sure that the kiln regulator is of adequate size, is installed
properly, and is working properly. Is there any chance that some teflon
tape or other obstruction could be lodged in the inlet of the kiln
regulator? Do your burners have individual valves on them? If so, when
just one burner is on, does the gauge on the kiln regulator read any higher
than 3 PSI? If not, then that regulator is DEFINITELY screwed up. Also,
what size are the orifices on these burners? Any chance they are too large,
as some people have suggested? Note above that the orifices on the large
GACO venturis we have on our salt kiln are only 3/32".
Let us know what cures this problem.
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Vince Pitelka on wed 3 dec 97
>hi all...a question for the kiln experts
>My new 65 cuft ifb d/draft kiln [the subject of two posts already this
>month] is still causing me headaches. I can't get enough gas pressure at
>the the kiln.
Ray -
After sending my earlier post, another thing occured to me. It definitely
sounds like the problem is in the regulator at the kiln, especially since
you said that you can get the pressure at the kiln up to 25 PSI when the
burners are shut off.
My statement that the pipe you are using is plenty big enough is conditional
on using fairly high pressure at the burners. Is that your intent? And if
you ARE planning to use fairly high pressure at the burners (5 to 20 PSI),
then you need to make sure you have the proper orifices for this kind of
pressure. On the other hand, if it is your intent to fire this kiln to cone
10 on less than 3 PSI, then you need much larger pipe sizes on your
feed-line and manifold, as others have suggested.
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Joseph Herbert on wed 3 dec 97
My feeling about Ray Carlton s kiln is that he doesn t have a pressure
problem, 3 psi is like 60 inches of water column and lots of kilns run on
single digit water inch pressures, he has a volume problem. There should be
some 2 inch pipe in this layout. Marc Ward can answer this question
definitively but there seems to be the need for bigger holes all the way from
the bottle to the burner. To supply a kiln with normal kinds of burners, you
need generous quantities of gas at rather low pressures. Takes big pipes to
do that. There are alternatives but big pipe is one answer.
Joseph Herbert
JJHerb@aol.com
Nan Rothwell on fri 5 dec 97
Vince wrote"Ray - You are getting a bunch of conflicting advice here,
including some which I think is very misleading. I do not think the problem
is in the pipe at all."
I'm with Vince on this one. I had a similar problem when first firing my
large, hardbrick slat kiln here. The propane people came out, and tried to
convince me that I needed to redo my whole plumbing to the kiln and/or
install a second, large propane tank... But in the end, it was the regulator
they had supplied, the one inside the kiln shed, that was the problem. I'd
look there before I redid any plumbing...
Nan Rothwell
WardBurner on sat 6 dec 97
Ray,
One item you have not mentioned in your posts, that will help determine your
problem, is the outlet pressure rating of your second stage regulator and the
capacities in cubic ft or BTU's of first and second stage regulators. My guess
is this is where the problem lies. You said;
<<<<>burners off. Why can't I do it while the burners are on???>>>>>
This usually indicated a volume problem, not a pressure problem, though it
shows up as too little pressure. Also, are you getting any ice formation on
your tanks? If you are, that will lead to a volume (amount of available gas)
problem. Call your LP supplier and find out about the capacity and outlet
pressure of the second and first stages. If you have ice formation, you need
more tanks or one large one. (500 gallon min.). If your supplier can't help
you, send us the brand and model numbers of your regulators.
Marc Ward
Ward Burner Systems
PO Box 333
Dandridge, TN 37725
USA
423.397.2914 voice
423.397.1253 fax
wardburner@aol.com
| |
|
