Preparations
28
28.08.2019
5.7.
Filling
Connect the external vessel first!
See chapter 5.4. Connecting an external , page 26.
Be aware of how the bath fluid changes volume within the
temperature control system's working temperature range.
Rule of thumb:
Expect about 12 % volume change for every 100 °C [212 °F]
temperature change.
Always check to make sure the drain screw is closed before filling.
Recommendation:
•
Use a 2-liter measuring cup or similar for filling.
•
Use a heat transfer fluid that is appropriate for your application.
5.7.1.
Sample Calculation: Determining whether an external expansion reservoir is needed
Assumption
:
The external vessel for this example is a reactor with capacity 5 l.
The length of the connection tube is 6 m, the inner diameter is 10 mm.
The bath fluid has a
thermal expansion coefficient
(
γ
) of 1.1
•
10
-3
K
-1
The temperature difference (
∆ϑ
) is 280
°
C.
The change in volume (
∆
V)
ο
f the bath fluid can be calculated as follows:
ϑ
γ ∆
⋅
⋅
=
∆
ges
V
V
In which V
ges
= V
M
+ V
S
+ V
G
V
M
= Jacket volume (approx. 1/3 of external reactor volume) = 0.33
•
5 l = approx. 1.65 l
V
S
= Volume of the tubes (A
•
l) = 78.5 mm
2
•
6 m = 0.47 l
V
G
= Volume of the active heat exchanger volume = 1.7 l
V
ges
= 1.65 + 0.47 + 1.7 = 3.82 l
∆
V
= 3.82 l
•
1.1
•
10
-3
K
-1
•
280 K = 1.18
•
20 % safety factor =
approx. 1.4 l
.
In this case, the internal usable expansion volume (please see technical data) would be sufficient.
With a reactor volume of 50 l in this example, the external expansion reservoir, offered by JULABO
(Order No. 8970833), would be necessary.
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