Appendix c — choosing a temperature bath liquid – Cannon Instrument CT-1000 (Contant Temperature Bath) User Manual
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CANNON
®
CT-1000 Constant Temperature Bath Instruction & Operation Manual
Revision 3.1e—June, 2011;
CANNON
®
Instrument Company
2139 High Tech Road • State College, PA • USA 16803
C
APPENDIX C — CHOOSING A
TEMPERATURE BATH LIQUID
The ideal bath liquid would possess low viscosity, high heat capacity, and
low vapor pressure over a wide range of temperatures. In addition, the
liquid should have a very high flash point and be relatively low in cost. If
the fluid is to be used in a kinematic viscosity bath where it is necessary
to view the instruments through the bath liquid, then it is important for
the liquid to be clear and without color. Unfortunately, no single fluid
meets all these requirements.
Because no single fluid can be used at all possible bath temperatures, the
choice of a suitable fluid must begin by establishing the temperature
range over which the bath will be operated. The following table provides
a list of operating temperature ranges and some liquids suitable for use in
these ranges:
)
C
°
0
0
2
+
o
t
C
°
0
0
1
-
(
S
N
O
I
T
P
O
D
I
U
L
F
H
T
A
B
e
r
u
t
a
r
e
p
m
e
T
)
C
°
(
e
g
n
a
R
s
d
i
u
q
i
L
h
t
a
B
e
l
b
a
t
i
u
S
C
°
0
1
+
o
t
C
°
0
0
1
-
l
o
h
o
c
l
A
l
y
h
t
e
M
C
°
0
2
+
o
t
C
°
0
1
-
s
e
n
o
c
il
i
S
y
t
i
s
o
c
s
i
V
-
w
o
L
,
l
o
h
o
c
l
A
l
y
p
o
r
p
o
s
I
C
°
0
6
+
o
t
C
°
5
+
s
e
n
o
c
il
i
S
,
s
l
i
O
y
t
i
s
o
c
s
i
V
w
o
L
,
r
e
t
a
W
)
t
S
c
1
,
d
i
u
l
f
0
0
2
w
o
D
(
C
°
0
0
1
+
o
t
C
°
0
6
+
s
e
n
o
c
il
i
S
,
r
o
t
i
b
i
h
n
I
n
o
i
t
a
d
i
x
O
h
t
i
w
s
l
i
O
e
t
i
h
W
)
t
S
c
0
1
,
d
i
u
l
f
0
0
2
w
o
D
(
C
°
5
3
1
+
o
t
C
°
0
0
1
+
)
t
S
c
0
2
,
d
i
u
l
f
0
0
2
w
o
D
(
s
e
n
o
c
il
i
S
C
°
0
0
2
+
o
t
C
°
5
3
1
+
)
t
S
c
0
5
,
d
i
u
l
f
0
0
2
w
o
D
(
s
e
n
o
c
il
i
S
Methyl alcohol
Methyl alcohol is relatively volatile, has a low flash point, and has a
degree of toxicity. The only reason for using it is that there seems to be
no reasonable substitute. There are some very expensive halogen-based
fluids which might be considered, but these also have a high volatility
and may be somewhat toxic.