Re: Measuring temperature

["Thomas Reed" <tombreed@attbi.com>]

Dear Ron and All:

Thermocouples are cheap and dependable for measuring temperatures, type K
(Chromel Alumel) up to 1200 C.

However, be careful to know what you are measuring.  A thermocouple placed
in a gas stream will radiate energy and read a temperature reflecting the
balance between convection in from the gas (weak, but velocity dependent)
and radiation out from the solid thermocouple (increasing with T^4).

Thus a metal thermocouple placed in a gas at 1600C may only read 1000 C.  It
is amazing how few good engineers realize this problem.  (There are methods
for correction, but much more complex and costly.)

I have a 12 point manual thermcouple digital readout on my panel board, cost
about $150.

Yours truly,                    TOM REED            BEF


----- Original Message -----
From: "Ron Larson" <ronallarson@qwest.net>
To: <stoves@crest.org>
Sent: Monday, March 11, 2002 8:55 AM
Subject: Fw: Measuring temperature


> stovers:
>
>     Getting this message from the solar cooking list, I looked up the web
> site below and found a good selection as advertised.  I have ordered their
> free literature - but not yet ordered any equipment.
>
>     My question is whether anyone on the stoves list has used thermometers
> to try to increase efficiency.  I don't remember any discussion of this
> topic.  Seems like we should be able to reduce excess secondary air and/or
> change parameters to increase the temperature at the bottom of the pot -
or
> reduce it at the top and have a pretty good real-time stand-in for
> efficiency.
>
>     Some of the thermometers shown have wide temperature range, multiple
> inputs, digital readouts and prices near $100.  Any thoughts?
>
> Ron
>
>
>
> ----- Original Message -----
> From: Chris Keavney <Ckeavney@mkl-mmaf.org>
> To: <solarcooking-l@igc.topica.com>
> Sent: Monday, March 11, 2002 7:18 AM
> Subject: RE: Measuring temperature
>
>
> TWIMC:
>
> My source for temperature-measureing equipment is Omega Engineering of
> Stamford, CT (www.omega.com).  They are a supplier for industry and
> laboratories, and they have a huge selection.
>
>
>
> Chris Keavney
> Maryknoll Mission Association of the Faithful
> PO Box 307
> Maryknoll, NY 10545
> 914-944-0300 ext. 221
>
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Stoves List Archives and Website:
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http://www.crest.org/articles/static/1/1011975339_7.html Gasification
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For information about CHAMBERS STOVES
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