Berthold LB 444 - Calculation of the Square Temperature Coefficient

Density Meter LB 444 SECTION 6. BASICS OF DENSITY MEASUREMENTS
56
Calculation of the Square Temperature Coefficient
If significant temperature variations are likely to occur in the product (approx. > ±
20°C), it is advisable to enter the square temperature coefficient as well.
Calculation:
a) Calculate TC
1
(see above)
b) With TC
1
calculate nominal value ρ
2
'
at higher temperature
ρ
2
'
= ρ
1
+ (ζ
1
- ζ
2
) · TC
1
c) Take actual density value ρ
2
from table
d) Calculate TC
2
:
( )
TC = -
-
-
2
2
'
2
2
ρρ
ζζ
1
2
e) Enter the calculated value TC
2
as temperature coefficient TC2.
Example:
Ethanol, concentration 30 %, reading in g/cm
3
, relative to 10°C.
1
st
temperature coefficient in range 10 - 20° C:
TC = -
0.9599 - 0.9540
10 20
= 0.59 10
1
-3
−
⋅
Input value in code XX47: 0.59 * 10
-3
Calculate nominal density value ρ
2
calculated with TC
1
at 100° C:
ρ
2
'
= 0.9599 + (10 - 100) · 0.59 · 10
-3
= 0.9068
ρ
2
(table value) = 0.8936
( )
TC = -
0.9068 - 0.8936
10 - 100
= 1.6296 10
2
2
-6
⋅
Input in code XX48: 1.6296 * 10
-6