Acid resistant, heat conductive electronics enclosure

sparky_guy

Hi,

I need to put an electronic measurement system into a very nasty environment. An Ore pile where the minerals are being extracted using sulphuric acid and the temperature is 100-150 degrees C.

I need an enclosure which will resist the acidic environment but conduct the heat to my temperature sensors inside. I also will communicate wirelessly (100s kHz) so thick metallic structures are not really an option. Ploymers with acid resist epoxys will fall down on heat conduction.

Initially I just need a demo, so something which will last 24 hours or so. But in the longer term we would be aiming at about a year survival in the ore pile. Any suggestions of a material which might meet my needs? Even for the demo

Cheers

Danger

Welcome to PF, Sparky Guy.
Would a Corningware baking dish with a silicone gasket work?

sparky_guy

An out of the box (and into the baking dish :) ) suggestion... i like it!

I will look into it, thanks

tygerdawg

Perhaps you could investigate the various alloys used for corrosive environments:

• stainless steels of various grades
• monel
• inconel

Then there is always fused ceramic, but that would be my last choice I think.

sparky_guy

I think stainless steel will affect my wireless transmission and the impedance of my antenna, but I will look into it in any case. Monel and inconel sound very expensive to work with.

How about glasses and polymers?

Travis_King

Have you looked into the various types of NEMA enclosures for industrial electronics and instrumentation panels?

Also, any enclosure is going to screw with your temperature sensors...Is it general practice to encase temperature sensors? Are you calibrating them after they are encased? Does the interior temperature of the case need to change simultaneously with the ambient temperature?

Bobbywhy

If all you want to measure is the temperature inside the ore pile there may be a different solution: change your design parameters.

Do not use wireless telemetry. If you remove that requirement, then your ore temperature may be monitored by a simple temperature sensor on a cable. Then you only need the sensor itself and its cable to be heat and acid-resistant.

Against_Laws

I was going to suggest stainless steel as it is a great heat conductor and is resistant to acids. What purity of Sulfuric acid are you dealing with? That stuff is tricky... The lower the purity the nastier it is.

Bobbywhy

Stainless steel may meet the corrosive enviroment requirement, but blocks but blocks RF data telemetry. I like Danger's "Corning Glassware" suggestion.

Against_Laws

How big is your setup? Is it just a simple probe? It'd be nice if we could see the design or setup you are thinking of. What about high density polyethylene? The average melting point for HDPE is around 120-130 degrees Celsius. Unless you were to use Pyrex like danger said.