Brookfield Bath, Model TC-101 Digital KU-1 Viscometer - Manual (Page 6)

APPLICATION NOTES
At fluid's low temperature extreme:
1. Presence of ice or slush will adversely affect temperature stability.
2. Viscosity above 10 centistokes will adversely affect temperature uniformity.
3. High fluid viscosity and high speed pumping will generate heat in the fluid.
At fluid’s temperature above ambient without using refrigeration:
1. Without refrigeration and within 15°C of room temperature the viscosity should be 10 centistokes or
less to avoid friction heating of the fluid. Encourage heat loss by uncovering the fluid and lowering
pump speed.
At fluid’s high temperature extreme:
1. Heat loss from vapor will cause poor temperature stability.
2. A fume hood may be required to prevent the buildup of vapors inside the room.
3. Use a cover and/or floating hollow balls to help prevent heat and vapor loss.
4. Fluid lost from vapor will have to be frequently replenished.
2.4 Circulator Pump
The two speed pressure (simplex) pump may be used for tempering of samples in the reservoir or for
circulation in closed loops. It is not designed for pumping from the circulator's reservoir into and out of
a second open reservoir. The HI or LO speed selection switch on the rear panel of the controller allows
a choice of pump speeds.
Maximum Pump Maximum Pump
Speed Outlet Ratings Outlet Ratings
Selection Line Frequency = 60Hz Line Frequency = 50Hz
HI 15 lpm / 2.6 psi 10.4 lpm / 1.8 psi
LO 7 lpm / 1.3 psi 4.8 lpm / 0.9 psi
The table uses the following criteria:
1. Maximum pump outlet flow rate is measured in liters per minute (lpm) with no restriction on the
pump outlet.
2. Maximum pump outlet pressure is measured in pounds per square inch (psi) at no flow.
3. Water was used as the circulation fluid. Water has a viscosity of one centistoke. High viscosity or
low density fluids will change these figures.
4. When the inlet and outlet are plugged on reservoir models, flow rate refers to internal bath
circulation.
Select the HI pump speed where changes in temperature vary and there is a need for fast recovery,
or when pumping to multiple external units. The LO pump speed is adequate for most applications
and provides quieter pumping.
2.5 Closed Loop Circulation
Connect the pump inlet and outlet to your application. Use care to avoid restrictions in the tubing in
order to maintain adequate flow. When connecting to more than five closed loops we recommend use
of a manifold made of "Y" adapters to divide the fluid into two or more banks. A booster pump may be
added without damage to the circulation bath pump. After setting up multiple closed loops, check that
there is adequate flow at the return manifold for each loop and recheck bath fluid level.
The control stability of a closed loop system will generally be better at the external apparatus than in
the immediate vicinity of the heater, provided the apparatus control point represents a constant load
and is well insulated For example, if you circulate at 50°C through a viscometer, the temperature
variation observed in the reservoir may be +0.05°C, whereas in the viscometer it may be only +0.02°C.
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