Documents/handbook relating to high temperature furnance design - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: April 23, 2018, 04:48:14 pm
content: Like furnaces that use MoSi or SiC. Spacing requirement between heating elements, power requirements calculation and other thermal design kinks relating to higher temperature furnances (reflection coefficent of walls important to prevent overheating of elements?)It looks like you can pretty much slap a furnace that runs at sau 1300c fairly easily with khandal wire or nichrome, but i cant seem to find anything useful for furnaces going from 1500c to 2000c. I am willing to use argon inert gas to protect the exotic elementsI intend to use regulated variable dc power and pid with specific algorithms relating to nonlinear behavior of heating eleme ts in the form of lookup table compensation for control.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 23, 2018, 04:59:14 pm
content: DC might be worse because of ionic drift in components. Who knows.The refractory isn't cheap. You can't even use pure alumina at that temperature. Somehow I don't think this is something you thought through very far...There's a graphite furnace described in Brauer, for 2500C or so. Lots of machined parts. Use in vacuum I think?Tim

author: oldway
author_rank: Super Contributor
timestamp: April 23, 2018, 05:23:01 pm
content: Kanthal heating elements are limited to 1850 °C....But this is perhaps only valid in air....Why don't you contact Kanthal to ask more informations ?https://www.kanthal.com/en/products/furnace-products-and-heating-systems/electric-heating-elements/

author: CopperCone
author_rank: Super Contributor
timestamp: April 23, 2018, 06:44:51 pm
content: nah they get worse with gas flow, those don't really care about reactivity too much, so long the temperature is high. They are MoSi type.Thats probobly what I plan on using. 1850C is plenty. I would probably not exceed 1700.I am more worried about the thermal design like spacing to prevent over heating and stuff like that.The elements don't like being around gas flow, or under vacuum that much, you need to derate for those factors.Picking the element type is the easy part.Different 'conventional' furnace design can be used for operation in colder temperatures, up to like 1200C.Was hoping someone had experience with this kind of equipment.

author: oldway
author_rank: Super Contributor
timestamp: April 23, 2018, 08:17:47 pm
content: I remember that Kanthal had published a very comprehensive guide to using their products with all the calculations and formulas and furnace construction details and practical examples.I had this book in 1980, but since then I have lost it.Look on the Kanthal website if it still exists or ask them if they can send it to you by mail.

author: Wolfram
author_rank: Frequent Contributor
timestamp: April 23, 2018, 10:27:49 pm
content: This Kanthal document has some info on furnace design with their MoSi elements:https://www.kanthal.com/globalassets/kanthal-global/downloads/furnace-products-and-heating-systems/heating-elements/mosi2-heating-elements/s-ka058-b-eng-2012-01.pdf

author: CopperCone
author_rank: Super Contributor
timestamp: April 24, 2018, 03:00:22 pm
content: That handbook has what i wanted but god damn those elements are expensive. I though maybe 30$ per. More like 400.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 24, 2018, 04:07:35 pm
content: Try and look up zirconia based insulation products.Hmm, I see fiber, batting and board type products offhand. No price listed, just quote forms.Tim

author: Neomys Sapiens
author_rank: Super Contributor
timestamp: April 25, 2018, 12:01:26 am
content: Nassheuer's Taschenbuch fuer Schutzgastechnik und Industrieofenbau, Vulkan-Verlag 1984unfortunately, German AND rare.