Fredrick Paget on tue 28 sep 04
> Reduction would be accomplished by bleeding a small amount of
>Hydrogen into the chamber from a small bottle.
Don't try this at home! Hydrogen and air mixtures over a very wide
range of concentrations are explosive.
The hydrogen will either just burn to give steam or it will blow the
roof off. Your choice.
We used to have hydrogen reduction muffle furnaces at Sylvania
lighting. Hydrogen in the furnace tube was 100 percent hydrogen and
to keep air out there was a pilot flame at each end of the tube. When
the little door was lifted the hydrogen escaped and burned harmlessly.
There is a paper on the web by a British author, Dr. Julian Malins;
"The Monitoring and Control of Specialist Ceramic
Kiln Atmospheres and Emissions" May 1993.
http://www2.rgu.ac.uk/criad/jm_abst.htm , who describes hydrogen
reduction in a ceramic kiln. He used an atmosphere of 95 percent
nitrogen and 5 percent hydrogen which is not explosive. You can get
the mixture in a gas cylinder from a welding gas supplier. I asked
one once and he said no problem.
Fred
--
From Fred Paget, Marin County, California, USA
fredrick@well.com
Mike Gordon on tue 28 sep 04
Hi,
I may have missed this point earlier but what size kiln were we
talking about for $ 36,921.? Mike Gordon
Hank Murrow on tue 28 sep 04
On Sep 28, 2004, at 8:03 AM, Mike Gordon wrote:
> Hi,
> I may have missed this point earlier but what size kiln were we
> talking about for $ 36,921.? Mike Gordon
>
Dear Mike;
The kiln we were talking about is 28 cu ft, lined with 2700 F fiber,
and is a doorless design, that is, it lifts electrically above the
setting. In the version I jokingly provided Mel a 'ball park' figure
for, it would be completely sealed, and have Glo Bar SiC elements
penetrating the ceiling of the chamber and running next to the fiber
walls. Reduction would be accomplished by bleeding a small amount of
Hydrogen into the chamber from a small bottle. I will come up with a
firm price once the Kanthal folks get back to me with data.
Meanwhile, for a look at the gas version, go to
http://www.ceramicsmonthly.org/mustreads/shinofire.asp and scroll down
past the Shino article to the kiln article. Or, visit
http://www.murrow.biz/hank/kiln-and-tools.htm on my site for a brief
visit. The gas version is installed and fired three times for around
$25,000 to $28,000.
Cheers, Hank
murrow.biz/hank
Ivor and Olive Lewis on wed 29 sep 04
Dear Hank and Mel,
For a practical take on the idea proposed by Hank, see Margery
Clinton, "Lustres", P 70 and imagine the electrical installations
which would be imposed on this kiln designed by Rod Siegwart with
modifications made for hoisting the bell (or is it Top Hat?)
I am suspicious about the "Hydrogen Bleed", having worked with
hydrogen atmosphere furnaces. How would you get the hydrogen to
pervade or infuse the whole volume before it ignited and burnt in the
atmospheric oxygen without doing an inert gas flush?
Those Hydrogen furnaces at Swift Levick. We had five, four were
operable, the fifth exploded during commissioning. They were infused
cold with pure hydrogen and the infusion was supposed to be completed
before the power was turned on. This was tested using the simple
method of collecting samples by air displacement and applying a light
to the mouth of the gas tube. A quiet burn was all we needed. But
inadvertently someone turned on the juice before facts were confirmed.
Thankfully the effects were not catastrophic, just spectacular. Life
in some factories can be interesting.
Best regards,
Ivor Lewis.
Redhill,
S. Australia.
----- Original Message -----
From: "Hank Murrow"
To:
Sent: Wednesday, 29 September 2004 3:27
Subject: Re: Hanks Kiln
> On Sep 28, 2004, at 8:03 AM, Mike Gordon wrote:
>
> > Hi,
> > I may have missed this point earlier but what size kiln were we
> > talking about for $ 36,921.? Mike Gordon
> >
>
> Dear Mike;
>
> The kiln we were talking about is 28 cu ft, lined with 2700 F fiber,
> and is a doorless design, that is, it lifts electrically above the
> setting. In the version I jokingly provided Mel a 'ball park' figure
> for, it would be completely sealed, and have Glo Bar SiC elements
> penetrating the ceiling of the chamber and running next to the fiber
> walls. Reduction would be accomplished by bleeding a small amount of
> Hydrogen into the chamber from a small bottle. I will come up with a
> firm price once the Kanthal folks get back to me with data.
>
> Meanwhile, for a look at the gas version, go to
> http://www.ceramicsmonthly.org/mustreads/shinofire.asp and scroll
down
> past the Shino article to the kiln article. Or, visit
> http://www.murrow.biz/hank/kiln-and-tools.htm on my site for a
brief
> visit. The gas version is installed and fired three times for around
> $25,000 to $28,000.
>
> Cheers, Hank
> murrow.biz/hank
>
>
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