Thermocouple into a rotating tank

Hi:

Someone could address how can I solve the mechanical/electrical problem 
to measure temperature from 20 thermocouple set into a 3 litre rotating 
tank which contains a electrically heated water?.

I have found that MOOG company offers a slip rotating rings but the 
contact resistance is about 60 mOhms. May be this contact resistance is 
a little high for micro-volts sources like thermocouples.

Any suggestion will be helpfully accepted.

Thanks at all.