04/03
347
LB
444
50
7.3
Function of Temperature Compensation
The temperature coefficient of a liquid is not constant over a large temperature range,
but usually it increases with rising temperatures. Temperature compensation is carried
out according to the following formula:
ρ
Ref
=
ρ
M
+ (
ϑ
P
-
ϑ
Ref
) · TC
1
+ (
ϑ
P
-
ϑ
Ref
)
2
· TC
2
ρ
Ref
= Density value compensated relative to
reference temperature
TC
1
= Linear temperature coefficient TC
1
TC
2
= Square temperature coefficient TC
2
ρ
M
= Measured density value
ϑ
P
= Product temperature
ϑ
Ref
= Reference temperature
(Terms in italics refer to parameters that have to be entered in the
Product Data
menu).
With minor temperature changes (approx. ± 20°C) it suffices, in most cases, to enter the
linear coefficient.
7.4
Temperature Compensation in Suspensions
The characteristic temperature curve of water is used for measurement of
suspensions
with water as carrier liquid
.
Proceed as follows:
In the Calibrate menu, select the function Suspension measure and Water TC.
Then you just have to enter the reference temperature.
A temperature coefficient need not be entered.
7.5
Calculation of Temperature Coefficients
Example:
Product:
HCl - water mixture
Measuring range:
20 - 40 weight % HCl
Temperature range:
10° - 30° C
Unit of measure:
g/cm
3
The temperature coefficient at average concentration (30%) is calculated as follows:
0.00059
=
30
10
1.1433
-
1.1551
-
=
-
-
-
=
TC
2
1
2
1
−
ϑ
ϑ
ρ
ρ
ρ
1
= Density in g/cm
3
at
ϑ
1
ρ
2
= Density in g/cm
3
at
ϑ
2
Input value: 5.9000e-04
Summary of Contents for LB 444
Page 1: ...Density Meter LB 444 Id No 32816BA2 Rev No 04 22 04 03 ...
Page 2: ......
Page 9: ...04 03 347 LB 444 VII ...
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Page 109: ...04 03 347 LB 444 99 13 4 Mounting Device 90 for Pipe Diameter 21 3 76 1 mm ...
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Page 117: ...04 03 347 LB 444 1 14 Ex Certificates for Evaluation Unit ...
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Page 120: ...04 03 347 LB 444 4 15 Ex Certificate for the Detectors ...
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