Reservoir
Fluids Use distilled water for temperatures from 10°C to
90°C or a mixture of laboratory grade ethylene glycol and
water for temperatures -25°C to 100°C. A variety of fluids
can be used depending upon your needs.
The
fluid must be chemically compatible with the reservoir and
with 300 series stainless steel in the pump and heater.
The fluid must also be able to produce the temperature range
desired.
For
temperature stability of ħ.01°C, the viscosity should be
50 centistokes or less at the lowest operating temperature
to allow good fluid circulation and to minimize heating
from the pump. Most single type of fluids will be able to
stabilize to ħ.01°C over a 100°C range.
|
FLUID
DESCRIPTION |
SPECIFIC
HEAT
@25°C |
NORMAL
RANGE |
EXTREME
RANGE |
|
Water
|
1.00
|
10°C
- 90°C |
2°C
- 100°C |
|
Ethylene
Glycol 30%
Water 70% |
.90
|
0°C
- 95°C |
-15°C
- 107°C |
|
Ethylene
Glycol 50%
Water 50% |
.82
|
-25°C
- 100°C |
-35°C
- 115°C |
|
Ethylene
Glycol 100% |
.62
|
50°C
- 125°C |
25°C
- 155°C* |
|
Methanol
60%
Water 40% |
.52
|
-45°C
- 0°C |
-----
|
|
Dynalene-HC
50 |
.76
|
-50°C
- 60°C |
-62°C
- 60°C |
|
DC200
5 cs
Silicone Oil |
.32
|
-35°C
- 65°C |
-50°C
- 125°C* |
|
DC200
10 cs
Silicone Oil |
.34
|
-20°C
- 80°C |
-35°C
- 165°C* |
|
DC200
20 cs
Silicone Oil |
.36
|
0°C
- 100°C |
-10°C
- 230°C* |
|
DC200
50 cs
Silicone Oil |
.39
|
50°C
- 150°C |
5°C
- 270°C* |
|
DC510
50 cs
Silicone Oil |
.39
|
50°C
- 150°C |
5°C
- 270°C* |
|
DC550
125 cs
Silicone Oil |
.42
|
100°C
- 200°C |
80°C
- 232°C* |
|
DC710
500 cs
Silicone Oil |
.45
|
150°C
- 250°C |
125°C
- 260°C* |
*WARNING
- Fluidıs flashpoint temperature. DC fluids are manufactured
by Dow Corning
Do
NOT use the following fluids:
1. Automotive antifreeze with additives**
2. Hard tap water**
3. Deionized water with a specific resistance > 1 meg
ohm
4. Any flammable fluids
5. Concentrations of acid or bases
6. Solutions with halides: chlorides, fluorides, bromides,
iodides or sulfur
7. Bleach (Sodium Hypochlorite)
8. Solutions with chromates or chromium salts **
At
temperatures above 40°C, additives or mineral deposits can
adhere to the heater. If allowed to build up, the heater
may overheat and fail. Higher temperatures and higher concentrations
of additives will cause a faster deposit build up, If buildup
occurs see section 6.1 Maintenance - Heater.
WARNING:
Do not use a flammable liquid as a fire hazard may result.
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
fluidıs 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. Heat loss can be encouraged
by uncovering the fluid and lowering pump speed.
At
fluidıs 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.
