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8.4.1 Calculating the Density of Individual Components
With suspensions one can usually assume that liquid and solid density are constant, ex-
cept when the liquid contains dissolved substances with different concentrations.
With solutions, one can use the suspension formula to allow simple calibration. It is bet-
ter, however, to use multi-point calibration without the suspension formulas (input “Sus-
pension measurement – No”) since with solutions the density of both components is not
constant due to the mixing ratio.
With suspensions the solid density is usually known and water is used as carrier liquid
(select Water TC and enter the Solid density); with solutions, on the other hand, the
density of the relevant components often has to be calculated from table values.
Enter the density of the carrier liquid or the density of the attendant component (mostly
water) at average temperature (reference temperature) as liquid density.
a) Table values are available as % concentration/density
ρ
ρ
ρ
ρ
S
L
L
C
C
=
−+
,
,
*
1
C’ = Concentration in weight percent / 100 (for example, at 20% C’ = 0.2)
ρ
L
= Density of the attendant component in g/cm
3
(liquid density)
ρ = Density of mixture in g/cm
3
at average concentration
ρ
S
= Density of the component to be measured (Solid density)
Example:
Product HCl - H
2
O
Measuring range: Concentration 10 - 30% HCl
Average temperature 20°C
Density ρ at 20°C and 20% concentration: 1.0980 g/cm
3
Density H
2
O (r
L
) at 20°C: 0.99823 g/cm
3
ρ
S
=
−+
=
0 2 0 99823
0 99823
10980
102
18294
.*.
.
.
.
.
Input liquid density: 0.99823
Input Solid density: 1.8294
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