What we do is we drop the thermocouple down from the mixer lid

Can you attach the thermocouple to the mixing blade?

It all depends on the configuration of your mixer assembly.

The most probable solution is to mount your calibrated thermocouple in paralled to the mixer shaft. This can be accomplished with something as simple as a fixed sleeve for the impeller shaft that has the probe bonded to it. If your shaft is hollow then you could just drop the probe down the centre and have a co-axial slip ring connector at the far end to connect to your meter.

I've read all the posts...

Hand held IR meter/gun will give you instant reading of the material itself.........which may vary in relationship to the proximity of the cooling wall///last contact with the cooling wall.

Available every where.

MR. GUY

i think doube thermowell may work

the outer shell of thermowell insulate the inter shell of thermowell from water

the thermocouple inserted in inner thermowell

type of temperature insulating foam between shells could improve better

To utilize existing controller, you could use a small sample pump, with insulated piping.With sufficient flow, and short pipe runs, thermal loss would be negligible.Good luck.