Larry Kruzan on fri 30 oct 09
Hi Gang!
This past year I have been playing with one of my gas kilns trying to
squeeze as much efficiency out it as possible. I choose this challenge in
order to save fuel (money), to do my part for the environment, and to get
away from using my electric kilns - if possible eliminating them all
together.
The kiln I started with was based on the shelves I have and a size that I
felt most potters could build without lots of expense or expertise. The
shelves I have are 12x24 inches which is a common size found at most
suppliers. The stacking area is 36" wide, 27" deep and 50" tall plus the
arch - about 26 cubic feet. It was built with K-26 IFB with 4" of Isowool
across the arch. The walls are one brick thick, with around 500 straight
bricks and about 40 #1 Arch bricks , the floor was made with hard bricks. I
used power burners because I had a couple on hand and had no atmospheric
burners but they would work just fine on this small kiln.
Overall this sounds very much like the vast majority of kilns in this size =
I
have seen, so what's the big deal? Well - how about the bisque firing I jus=
t
completed that has over two hundred pieces in it, took 5 hours and used jus=
t
11 gallons of propane. Yep, 11 gallons at $1.45 per gallon for a cost of
$15.95. My last cone 10 reduction firing consumed a total of 19 gallons
with great results.
When I first built this kiln I was using 48 gallons for a cone 10 firing so
the savings are very real - 19 gallons, twice what I am using now.
So what did I do? First I added the 4" of Isowool I mentioned before,
secondly I elevated the bottom shelves one brick above the flue port. I wil=
l
be the first to loudly proclaim that I don't understand why this should hel=
p
but as soon as I did it the kiln temp evened out top to bottom, the damper
became much less sensitive and fuel consumption dropped like a rock. My
other two gas kilns use a lot more fuel and I intend to modify them along
the same lines soon. One of those is my test kiln that has a stacking area
24x24x36 inches and uses over twice as much propane as this one.
I'll be posting pics of the floor as soon as I get it unloaded Monday. In
the mean time I would appreciate any information you might want to share
about how much fuel your gas kiln consumes. Also if this change makes sense
to you please share.
Larry Kruzan
Lost Creek Pottery
www.lostcreekpottery.com
Dennis Gerasimov on sat 31 oct 09
Larry, which oxygen probes are you using? Everything I was able to
google up was way too expensive: $1k+.
Thanks for any pointers!
Dennis
Larry Kruzan wrote:
> My test kiln has three oxy probes, six pyrometer thermocouples, water col=
umn
> gages for gas and forced air on each burner all in an effort to understan=
d
> what is going on and why. One thing I am not monitoring the oxy level in =
the
> flu compared to the chamber - that's next.
>
Des & Jan Howard on sat 31 oct 09
Larry
The spouse of a member of our local pottery group has
been carrying on about increasing efficiency of our gas
kilns. He maintains he can reduce gas usage by minimum
15%. He just isn't listening when I keep telling him
our fibre kilns use bugger-all gas & all I've got to do
is put 12 tea light holders in the kiln & the total gas
bill is paid. The kiln can hold at least 70 of the
little darlings in unused spots.
While I was away roaming for a bit, Trev, the workshop
associate, did the packing & firing & bragged on how
fast he could fire the kiln, by firing for 6 hours
instead of my preferred 8 hour cycle.
Unfortunately the pots didn't cut it, requiring an
average mark-down of 10% from base prices.
The 8 hour cycle produced better pots with
an average 25% mark-up on base prices.
So, to me efficiency is not in using fewer resources
but in getting the maximum return from resources used.
Des
Larry Kruzan wrote:
> This past year I have been playing with one of my gas kilns trying to
> squeeze as much efficiency out it as possible. I choose this challenge in
> order to save fuel (money), to do my part for the environment, and to get
> away from using my electric kilns - if possible eliminating them all
> together.
--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850
02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624
Larry Kruzan on sat 31 oct 09
Hi All,
I received a few emails asking why I had three oxy probes on the kiln I'm
playing with right now. Basically, it's just to monitor several areas at th=
e
same time.
There is one just below the arch alongside the flu. One in the center of th=
e
door and one low beside the flu in the back wall.
The pyrometer thermocouples are scattered all over it.
The more data I can compile with multiple firings the better we can
understand what is going on - I hope. Of course I could always end up more
confused and decide to go play with something more simple - rocket science
maybe?
Chin UP all!
Larry Kruzan
Lost Creek Pottery
www.lostcreekpottery.com
Larry Kruzan on sat 31 oct 09
Hi Des,
Right on Bro! If the pots are crap all I'd be doing is wasting fuel AND
materials - I sure am not trying to do that.
The cone 10 reduction firings have been producing excellent results with no
more rejects than a firing did before any modifications were made. Perhaps =
I
didn't state that clearly (I was a little tired last night) but since I mak=
e
my living off my pots I have no desire to lose even one - literally food of=
f
the table.
I'll be posting my firing schedule next week as I do the next cone 10
firing, it is not a fast schedule and it allows plenty of stops to let
everything catch up. Mostly it is monitoring the oxy probe to make sure tha=
t
I really am in reduction and that I am not over reducing - unless I want to
that is.
My test kiln has three oxy probes, six pyrometer thermocouples, water colum=
n
gages for gas and forced air on each burner all in an effort to understand
what is going on and why. One thing I am not monitoring the oxy level in th=
e
flu compared to the chamber - that's next.
Again I would sure be receptive to any input.
Thanks,
Larry
-----Original Message-----
From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Des & Jan
Howard
Sent: Saturday, October 31, 2009 3:46 AM
To: Clayart@LSV.CERAMICS.ORG
Subject: Re: Kilns and fuel consumpsion
Larry
The spouse of a member of our local pottery group has
been carrying on about increasing efficiency of our gas
kilns. He maintains he can reduce gas usage by minimum
15%. He just isn't listening when I keep telling him
our fibre kilns use bugger-all gas & all I've got to do
is put 12 tea light holders in the kiln & the total gas
bill is paid. The kiln can hold at least 70 of the
little darlings in unused spots.
While I was away roaming for a bit, Trev, the workshop
associate, did the packing & firing & bragged on how
fast he could fire the kiln, by firing for 6 hours
instead of my preferred 8 hour cycle.
Unfortunately the pots didn't cut it, requiring an
average mark-down of 10% from base prices.
The 8 hour cycle produced better pots with
an average 25% mark-up on base prices.
So, to me efficiency is not in using fewer resources
but in getting the maximum return from resources used.
Des
Larry Kruzan wrote:
> This past year I have been playing with one of my gas kilns trying to
> squeeze as much efficiency out it as possible. I choose this challenge in
> order to save fuel (money), to do my part for the environment, and to get
> away from using my electric kilns - if possible eliminating them all
> together.
--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850
02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624
Des & Jan Howard on sun 1 nov 09
Larry Kruzan wrote:
> but since I make
> my living off my pots I have no desire to lose even one - literally food =
off
> the table.
Making a living exclusively from pottery sales does
tend to focus ones mind.
> My test kiln has three oxy probes, six pyrometer thermocouples, water col=
umn
> gages for gas and forced air on each burner all in an effort to understan=
d
> what is going on and why. One thing I am not monitoring the oxy level in =
the
> flu compared to the chamber - that's next.
> Again I would sure be receptive to any input.
Your setup will tell you what is happening, a handy
extra is a record of what the results were.
When sussing out a new kiln or after a major overhaul
we make kiln maps. Cones & test strips coated with our
most variable, but known results, glazes are placed on
every shelf. The fired results are noted on a 3D map of
the kiln.
Des
--
Des & Jan Howard
Lue Pottery
Lue NSW
Australia
2850
02 6373 6419
www.luepottery.hwy.com.au
-32.656072 149.840624
Larry Kruzan on sun 1 nov 09
Hi Dennis,
Mine came from Axner. Sadly, that is the going rate. I have a friend who is
experimenting with oxygen sensors from trucks and has met with some success
but they are very short. In order to get them long enough to use you need a
platinum wire to make it longer - that's the most expensive part, the rest
he salvages from a junk yard. The meter is just a common multi-meter.
One of mine I got from a potter selling out - had to commit to buy a bunch
of materials he had before he would part with it. Harder to find used than
anything. At times you can find a used one that is not working - if it was
not dropped, chances are that the platinum wire is broken. It can be sent t=
o
Axner for repair for around $200. If it was dropped the $200 repair is the
starting point - I'd really pass on one that was dropped myself.
One is enough for almost anyone except a "pointy headed nerd" that is sure
there is a better way. I just have to know what is going on in there.
I'm sorry I don't have better information, but if I hear of anything
floating around I'll drop you a line. Same for if Danny figures out how to
make his junkyard special running.
Best Wishes,
Larry
-----Original Message-----
From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Dennis
Gerasimov
Sent: Saturday, October 31, 2009 10:17 PM
To: Clayart@LSV.CERAMICS.ORG
Subject: Re: Kilns and fuel consumpsion
Larry, which oxygen probes are you using? Everything I was able to
google up was way too expensive: $1k+.
Thanks for any pointers!
Dennis
Larry Kruzan wrote:
> My test kiln has three oxy probes, six pyrometer thermocouples, water
column
> gages for gas and forced air on each burner all in an effort to understan=
d
> what is going on and why. One thing I am not monitoring the oxy level in
the
> flu compared to the chamber - that's next.
>
KATHI LESUEUR on sun 1 nov 09
A low tech alternative to the Oxyprobe is a Fyrite CO2 analyzer from
Bacarach. The low tech model not the electronic. It needs a quartz
tube to take the sample. About $100 from Bacarach or about $15 from
Superior Glass in Ypsilanti, MI. If you can get a hold of a copy of
George Wettlaufer's book "Getting into Pots" the whole process is
explained.
KATHI LESUEUR
http://www.lesueurclaywork.com
On Nov 1, 2009, at 7:12 PM, Larry Kruzan wrote:
> Hi Dennis,
>
> Mine came from Axner. Sadly, that is the going rate. I have a
> friend who is
> experimenting with oxygen sensors from trucks and has met with some
> success
> but they are very short. In order to get them long enough to use
> you need a
> platinum wire to make it longer - that's the most expensive part,
> the rest
> he salvages from a junk yard. The meter is just a common multi-
> meter.....
>
>
> -----Original Message-----
> From: Clayart [mailto:Clayart@LSV.CERAMICS.ORG] On Behalf Of Dennis
> Gerasimov
> Sent: Saturday, October 31, 2009 10:17 PM
> To: Clayart@LSV.CERAMICS.ORG
> Subject: Re: Kilns and fuel consumpsion
>
> Larry, which oxygen probes are you using? Everything I was able to
> google up was way too expensive: $1k+.
> Thanks for any pointers!
> Dennis
>
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