High temperature heating element for 600DegC ( 1112DegF )

I should heat a gas stream with a non-magnetic
heating element to a bit less than 600 Degrees
Celsius (1112Fahrenheit) Best would be some
resistive foil or wire that can be mounted in
a 6mm diameter quarz tube. The power, a few 10
Watts. The wire or foil should not evaporate
into the gaz stream, thus the temperature spread
should be low over the surface. Actually the
surface temperture should be as low as possible.
A few 10 degrees more at most.

The application is for one-of.

Rene

 

Thanks Spehro,
The gaz, best would be air, but if oxidation
became a problem then we might go to nitrogen.
We use it as heat transport medium, to heat
some solid that cannot be heated directly.

Ni-chrome is an idea. I'll have a look whether
we can get that. For a single layer coil with
the return in the middle, the stiffness of the
coilwire should be sufficient. Ni-chrome is even
having an own oxide layer, meaning it won't
oxidize in air.

Rene

 

OK, go ahead! ;-)

I've seen red-hot nichrome that didn't evaporate. What the
heck are you heating, Sulfuric Acid vapor? ;-)

Cheers!
Rich

 

What kind of gas? Any reason you can't use a coil of nichrome wire?




Best regards,
Spehro Pefhany

 

You should be able to find candidate heating elements in your nearest
toaster oven or even hair dryer. I'd sure be tempted to cruise on down to
the local hardware store to see what was available.

--
Tim Wescott
Control systems and communications consulting
http://www.wescottdesign.com

Need to learn how to apply control theory in your embedded system?
"Applied Control Theory for Embedded Systems" by Tim Wescott
Elsevier/Newnes, http://www.wescottdesign.com/actfes/actfes.html

 

Perhaps it could be wrapped around a smaller quartz or ceramic tube so
the return wire would be insulated.

Your 600°C should be fine for long life in air with ordinary Nichrome,
but there are less common (and more expensive) alloys such as Kanthal
A1 that work well at higher temperatures such as 1100°C or more,
however IIRC Kanthal is magnetic at lower temperatures.


Best regards,
Spehro Pefhany

 

The heater in a laser printer is a halogen lamp, which could be
mounted
in one focus of an elliptical-cylinder reflector so as to evenly heat
the other focus. Pack some dark medium into a quartz tube
and run your gas through that to get it up to a uniform temperature.

 

.

http://www.mcmaster.com/nav/enter.asp?pagenum=3591

Cheers!
Rich

 

Heck, check thrift shops and garbage[SIC] sales. ;-)

Cheers!
Rich

 

Used Nichrome is a lot more brittle and hard-to-work-with than new
Nichrome.

Best regards,
Spehro Pefhany

 

Thanks, but a halogen lamp is just not
surviving too many hours.

Rene

 

Thanks Rich,

that is an interesting supplier. The nickel-chrom wire
appears to be standard item. I'll have to spend some
time figuring out the resisivity vs. temperature as well
as the possible magnetic properties.

Rene

 

Here ya go!
http://www.wiretron.com/nicrdat.html

Cheers!
Rich

 

My news server stinks, I had to go to google groups to read most of this
thread.
While you're checking McMaster-Carr, they also carry thin ceramic tubes,
which you could use for your return. Don't depend on wire having the same
mechanical properties at operating temperature. I do this stuff every day,
drop me an email Monday morning, I can probably give you the material you
need - ralph dot naylor at eichenauerusa dot com Spehro's right about the
Kanthal alloys, they're tough, but they're composed of iron, aluminum and
silica. Come to think of it, nickel is ferromagnetic also. I've never
checked any of our wire for magnetic properties, it's never been an issue.
Something to do Monday, I guess. Does the wire have to be non-magnetic at
room temperature, or only at operating temperature?

Best regards,

Ralph in NH
http://www.eichenauerusa.com