Proline Promag 55 FOUNDATION Fieldbus
Commissioning
Hauser
71
6.3.4
Measuring the flow of solids
In certain areas of industry, raw materials that are very inhomogeneous or which contain
considerable quantities of solids, are transported and processed on a daily basis. Ore slurry, plaster
or viscous pulps are only some examples. When measuring flow in the mining industry or, for
example, in applications with suction dredgers, it is often not just the volume flow in a pipeline that
is of interest but also the proportion of solids being transported along.
To record this flow of solids, electromagnetic flow measurement is usually combined with
radiometric density measurement (total fluid density). If the total fluid density, solids density (target
fluid) and the density of the transported fluid (carrier fluid) are known, e.g. as a result of laboratory
testing, both the volume and mass flow can be calculated in addition to the proportion of individual
components in mass, volume or percentage units (
Solids content flow measurement using Promag 55
Promag 55S has special functions for calculating the flow of solids. In order to do so, the following
preconditions must be met:
• "Solids content flow" software option (F-CHIP)
• Analog Output function block (AO)
• A density measuring device, e.g. "Gammapilot M" from Hauser, for recording total fluid
density (i.e. incl. solids)
• Knowledge of the density of the solids, e.g. resulting from laboratory testing
• Knowledge of the density of the transport fluid, e.g. resulting from laboratory testing or from
reference tables (e.g. for water at 22 °C)
The following process variables can be calculated using Promag 55 and issued as an output signal:
• Volume flow total fluid (transport fluid + solids)
• Volume flow carrier fluid (transported fluid: e.g. water)
• Volume flow target fluid (transported solids: e.g. stone, sand, lime powder etc.)
• Mass flow total fluid
• Mass flow carrier fluid
• Mass flow target fluid
• % proportion of carrier fluid (volume or mass)
• % proportion of target fluid (volume or mass)
a0006118
Fig. 47:
Solids content flow measurement (m) using a density and flow measuring device. If the density of the solids
(
ρ
S
) and of the transport fluid (
ρ
C
) are also known, these can be used to calculate the solids content flow.
1
Flowmeter (Promag 55S)
→
Volume flow (V). The density of the solids (
ρ
S
) and of the transported fluid (
ρ
C
) must
also be entered into the transmitter.
2
Density measuring device (e.g."Gammapilot M")
→
Total fluid density
ρ
M
(transport fluid and solids)
r
C
r
S
1
2
r
M
m
V
