Thermal-Insulation for a circuit INSIDE a wood-digester!

[jerryagashe]

Hello

I have a temprature-pressure sensing/logging circuit on a PCB (8cmx3cmx0.5cm) that needs to be attached to a float, inside a client's wood digester (in a pulp and paper mill). I am completely stumped as to what material I need to use for the casing to sheild my circuit from the 200?C, 200 psi operating environment. Unfortunately, active cooling is not an option. Any suggestions will be greatly appreciated.

- Jerry

 

[kenvlach]

Teflon-coated stainless.

 

[EdStainless]

Will you equipment run at 200C? If not then you must cool it. Even with the best insulation it will slowly heat up to that temp. If you can't activly cool then your PCB needs to function at 200C. Good luck.
How much power do you have available? Battery only? You could use a thermoelectric cooler on critical parts and reject the heat into the digester, but these draw quite a bit of power.

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