High temperature heating element for 600DegC ( 1112DegF )

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.

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.

On Tue, 21 Aug 2007 23:30:39 +0200, Rene Tschaggelar wrote: ...

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!

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