PTFE Lined Thermowells

Hi,

I have an application that I am wondering if the Ultra-Metal tantalum surfaces is a good solution for. I have several thermowells in a very corrosive HCl environment (80C, 20%). From a corrosion point of view, it seems the HCl will eventually work its way through the PTFE liner. I believe the tantalum surface should help me here but please advise. Additionally Im not really happy about using a PTFE liner on my thermowell due to low thermal conductivity of it. Having such a good thermal insulator on my instrument that is supposed to measure temperature is a concern. How does the Ultra-Metal tantalum surface affect this?

John M

Hello John,

To answer your questions.....First of all PTFE/PFA liners are indeed permeable to warm HCl vapors. So your experience in seeing corrosion on the back side of the thermowell is quite common. The Ultramet CPT tantalum surfaces will definitely fix this issue as HCl will have no corrosion rate on the tantalum metal and the Ultra-Metal tantalum surface is impermeable to HCl vapors.

From a thermal conductivity point of view, the Ultra-Metal tantalum surface is excellent. Tantalum has a very high thermal conductivity and because its diffused into the steel of the thermowell there is no air gap or space between the tantalum metal and the thermowell. This allows for faster response times and accuracy of the thermowell.

To learn more, check out
ultrametcpt.com/instrumentation/acid-resistant-thermowells.html

Ultramet CPT Corrosion Experts