Prediction of batch heat transfer coefficients for pseudoplastic fluids ...

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Three vertiehl grooves 1/16 x 1/16 inches It,Jere machined
in the inside 'ltIall of the vessel, extending dov-m from the
top 8, 14,and 18 inches.
Iron-constantan thermocouple
wires encased in a 0.04 inch diaY'leter 316 stainless steel
sheath Here placed in the three grooves.
(One sheath per
groove. )
The tip of the sheath v!as bent slightly tm..rard
the inside of the vessel ELYld
the sheaths Here then cemented
in place 1,-]"i th the tip of the sheath flush l,,)'i th the inner
surface of the vessel wall.
The sheath extended up the
groove to the top and from there to a junction block in a
protected spot behind the vessel. The entire groove l'!aS
filled with a heat transfer cement having the same thennal
conductivi ty as 316 stainless steel (mermon T-85/~
Arter
the cement had hardened the excess vms sanded off to give
the inside wall a smooth surface.
In this manner the surface
temperature is measured Nithout interfering with the heat
f'loH in the 'lATall and 1ili thout having the thermocouple leads
dangling in the solution. The heat transfer cement was
used because
a. Its thermal conductivity vJaS the same as
that of the wall.
b. Regular solder may have caused corrosion
problems.
c. The use of silver soldermtp.t have damaged
the thermocouple junction.
Figure 4-2 shows the placement of the sll.rface or wall
->: Trademark of Thermon HaYlufac turing Co., Hous ton, Texas.