Berthold LB 444 - Page 60

Density Meter LB 444 SECTION 6. BASICS OF DENSITY MEASUREMENTS
55
For other units of measure (e.g. °Bx, %-concentration, g/l, etc.), the temperature
coefficient has to be converted accordingly. To do this, one first has to calculate
the density change/unit of measure obtained for the measuring range (e.g. %):
Density change
Concentration change
=
C
=
CC
C1 C2
1 2
∆ρ
∆
ρ
ρ
−
−
ρ
C1
= Density at average temperature and minimum concentration in the
measuring range.
ρ
C2
= Density at average temperature and maximum concentration in the
measuring range.
Example:
ρ
C1
at 20° C and 20 % HCl = 1.0979 g/cm
3
ρ
C2
at 20° C and 30 % HCl = 1.1493 g/cm
3
∆ρ
∆
C
=
1.0979 - 1.1493
20 % - 30 %
= 0.00514
g
cm • %
3
The temperature coefficient TC' for the unit % is calculated as follows:
TC' =
TC
C
=
0.00059
0.00514
= 0.11478
1
∆ρ
∆
Input value: 0.11478