Roland Beevor on thu 26 apr 12
Mel Jacobsen wrote
On 26/04/2012 00:33, mel jacobson wrote:
> we measure the reduction by the back pressure. and we actually
> measure the length of the back pressure flame from a standard
> spy hole. usually in the middle front of the kiln. 2-3 inches of flame.
Thanks for this Mel.
I've joined a group firing a Joe Finch (modified Olsen)
kiln here in Northumberland UK, at Broadwood Hall, near
Allendale. There are some very experienced potters, but
not the length of experience you have with wood firing.
I guess part of your certainty about where you are with
reduction stems from having used the Oxyprobe in the past?
I've been reading an old book, The Energy Efficient
Potter, Regis C Brodie 1982. Its full of interesting
ideas, and one section is on testing oxygen and CO2.
The technology looks rather quaint at 30 years remove,
but the principles are the same. We don't have on
Oxyprobe or access to one, and it would be expensive to
import, but there are flue gas analysers which measure
oxygen and CO, one is a Kane 250. I don't know whether
these are intended for lower temperature gases than you
get inside a kiln, but I'd be interested to know whether
other people have used them, and how helpful they have been?
Roly Beevor
Robert Harris on thu 26 apr 12
If you have some tech-minded DIYers in your group there are
instructions floating around the web (not sure where) to make a home
made oxyprobe from a multimeter and the O2 sensor from a car engine
(Catalytic converter, or the fuel injector perhaps?) I believe these
oxy sensors can be had fairly cheaply.
On Thu, Apr 26, 2012 at 4:43 AM, Roland Beevor
wrote:
> Mel Jacobsen wrote
>
> On 26/04/2012 00:33, mel jacobson wrote:
>>
>> we measure the reduction by the back pressure. =3DA0and we actually
>> measure the length of the back pressure flame from a standard
>> spy hole. =3DA0usually in the middle front of the kiln. 2-3 inches of fl=
am=3D
e.
>
>
> Thanks for this Mel.
>
> I've joined a group firing a Joe Finch (modified Olsen)
> kiln here in Northumberland UK, at Broadwood Hall, near
> Allendale. =3DA0There are some very experienced potters, but
> not the length of experience you have with wood firing.
> I guess part of your certainty about where you are with
> reduction stems from having used the Oxyprobe in the past?
>
> I've been reading an old book, The Energy Efficient
> Potter, Regis C Brodie 1982. =3DA0Its full of interesting
> ideas, and one section is on testing oxygen and CO2.
> The technology looks rather quaint at 30 years remove,
> but the principles are the same. =3DA0We don't have on
> Oxyprobe or access to one, and it would be expensive to
> import, but there are flue gas analysers which measure
> oxygen and CO, one is a Kane 250. =3DA0I don't know whether
> these are intended for lower temperature gases than you
> get inside a kiln, but I'd be interested to know whether
> other people have used them, and how helpful they have been?
>
> Roly Beevor
--=3D20
----------------------------------------------------------
Eric Ciup on thu 26 apr 12
-------- Original Message --------
Subject: Re: reduction and cones
Date: Thu, 26 Apr 2012 09:39:34 -0400
From: Eric Ciup
To: LISTSERV@LSV.CERAMICS.ORG
I used a co2 meter for years. They work very well to give you an idea of
reduction and combustion efficiency but they are not without their
quirks. You have to take your readings in a consistent manner to get
reliable results. Your highest readings are with a neutral flame and
they drop on both the oxidation and reduction side so you have to be
careful where exactly you are in the firing. I always used a 5 or 6 foot
length of thin copper tubing to take my gas samples. I would stick this
in the peep to take the sample and then remove it, in this way the tube
will last for years.
Nowadays I just eyeball my firings but if I had to build a new kiln
I would definitely dig out my CO2 meter.
> I've been reading an old book, The Energy Efficient
> Potter, Regis C Brodie 1982. Its full of interesting
> ideas, and one section is on testing oxygen and CO2.
> The technology looks rather quaint at 30 years remove,
> but the principles are the same. We don't have on
> Oxyprobe or access to one, and it would be expensive to
> import, but there are flue gas analysers which measure
> oxygen and CO, one is a Kane 250. I don't know whether
> these are intended for lower temperature gases than you
> get inside a kiln, but I'd be interested to know whether
> other people have used them, and how helpful they have been?
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