Veronica Honthaas on mon 27 nov 00
Last spring we started getting gas with lower BTU's. We went from 1120 to
970.My kiln, with old Venturi type burners,now that takes forever to make
it to cone 10......can take 40 hours!
We have tried adjusting everything from the gas to oxygen and nothing
works.Everything moves well up to cone 1 and then I am lucky to get a 20
degree rise per hour.
I am considering lining with ITC and getting forced air burners but I am
not sure that will help with the low BTU's.
I have 1/2 lb pressure with 14 inches water column.
Any suggestions.Veronica
Kenneth D. Westfall on tue 28 nov 00
Veronica
You need to figure out the total BTU your kiln required to make temp.
Then adjust for the drop in BTU. Divide the required BTU by the 970 BTU
per cubic feet and increase the burner orifice to supply the total volume
needed to produce kiln temp. The other alternative is increasing the gas
pressure so more volume will pass threw your currant orifice or add more
burners. Increasing gas pressure would be more difficult and probably
would requiring a lot of talking to get the gas company to change you over
to high pressure gas if at all possible.
You could also change over to propane which also would require a change
in orifice size. Propane has a higher BTU rate then natural gas.
Kenneth D. Westfall
Pine Hill Pottery
R.D. #2 Box 6AA
Harrisville, WV 26362
pinehill@ruralnet.org
http://www.pinehillpottery.com
Mike Gordon on tue 28 nov 00
Hi Veronica,
Have you tried injecting some propane into the burner ports? After the
kiln seems to stall you mught try periodic injections or if you have a
large enough supply ( big tanks ) tou can run it continuously. Mike
Gordon
Steve Mills on wed 29 nov 00
Talk to Marc Ward, he'll sort you out.
Steve
Bath
UK
In message , Veronica Honthaas writes
>Last spring we started getting gas with lower BTU's. We went from 1120 to
>970.My kiln, with old Venturi type burners,now that takes forever to make
>it to cone 10......can take 40 hours!
>We have tried adjusting everything from the gas to oxygen and nothing
>works.Everything moves well up to cone 1 and then I am lucky to get a 20
>degree rise per hour.
>I am considering lining with ITC and getting forced air burners but I am
>not sure that will help with the low BTU's.
>I have 1/2 lb pressure with 14 inches water column.
>
>Any suggestions.Veronica
--
Steve Mills
Bath
UK
Louis Katz on wed 29 nov 00
I have had two problems that created the same problems. The first is that my
burners get bug nests in the orifices restricting gas flow. The second is that I
have had a Baso safety valve fail to open fully due to corrosion.
Louis
Steve Mills wrote:
> Talk to Marc Ward, he'll sort you out.
>
> Steve
> Bath
> UK
>
> In message , Veronica Honthaas writes
> >Last spring we started getting gas with lower BTU's. We went from 1120 to
> >970.My kiln, with old Venturi type burners,now that takes forever to make
> >it to cone 10......can take 40 hours!
> >We have tried adjusting everything from the gas to oxygen and nothing
> >works.Everything moves well up to cone 1 and then I am lucky to get a 20
> >degree rise per hour.
> >I am considering lining with ITC and getting forced air burners but I am
> >not sure that will help with the low BTU's.
> >I have 1/2 lb pressure with 14 inches water column.
> >
> >Any suggestions.Veronica
>
> --
> Steve Mills
> Bath
> UK
>
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Veronica Honthaas on wed 29 nov 00
Thanks for the tips on correcting my low BTU natural gas. Actually
increasing the orifice size was my original suggestion but it got nixed by
our local clay gurus (I wish we had tried it!).
Yesterday, Mark Ward recommended increasing gas pressure 30% to counter
the effects of the 15% drop in BTU's.The gas company came out this morning
and gave me more pressure (2 lbs........that was the next increment they go
to.) So now I have to make sure not to use too much pressure. I have also
increased my port size.
I'll let you all know how it works when we fire again this weekend. These
suggestion will help a lot of high fire potters in our area who are
struggling getting to cone 10 these days.
PS: The folks at the gas company were wonderful. Knowing that it was
Christmastime and I needed to fire they even asked my husband about the
state of my mental health!!!! They got someone out right away.
Thanks for all the help.
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