KROHNE CORIMASS MFC 85 EN - Manual (Page 3)

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1. Introduction
The standard MFC 081 and 085 Mass Flow Converters enable the direct measurement of the
overall mass flow, mass total, density, and temperature of the process fluid passing through
the flow tube. From the mass flow and density measurements it is then possible to calculate
additional values for volume flow and volume total.
If the process fluid is a mixture of two components, then, given data on those components, it is
possible to infer, from the measured density, what the proportions of those components must
be. Clearly, if the two components have the same (or similar,) individual densities then the
mixture will also have the same density regardless of the relative proportions of the
components. Hence no concentration calculations will be possible for this case. As the
difference between the component densities increases, it then becomes easier to accurately
determine the relative proportions of the components.
The MFC081 and 085 converters are available with enhanced software which can calculate the
concentrations of the solid/solute components within various mixtures. Typical mixtures
include:
solid / liquid suspensions or slurries
oil / water emulsions
dissolved solids in water or other solvent.
Owing to the diverse physical and chemical properties of such a range of mixtures no one
concentration equation can fit all cases. Hence five different versions of concentration software
are available.
General Concentration
This is a freely programmable algorithm for mixtures of two immiscible components,
(oil / water emulsions or solid / liquid slurries). It can also be used for most other
mixtures but the range of accurate measurements can be limited.
Brix
Concentration of sucrose in pure water measured in °BRIX
Baumé Rational
Baumé Commercial
Concentration of sucrose in pure water measured in °BAUMÉ. There are two slightly
different versions of this scale with the “COMMERCIAL” version used more in the USA
and “RATIONAL” in Europe.
Sodium hydroxide, NaOH, Concentration
Concentration of aqueous sodium hydroxide, (NaOH), solutions.
All these different software versions provide measurements for Concentration, (in units of
°Brix, °Baumé or as a percentage by mass). They also provide a Solute Flow Rate so that the
mass flow rate of the solid / solute can be displayed. In addition the GENERAL
CONCENTRATION option provides a concentration by volume display.
Please Note:
The concentration measurements can only be as good as the density measurement from
which they are derived. For best performance it is recommended that the process should be
operated at a stable temperature and the density measurements should be site calibrated at
that temperature. Any sudden changes in temperature should be avoided.