Bronkhorst®
Instruction Manual mini CORI-FLOW ML120
9.17.097G
50
5.1.3
Estimated dosing time
With
proportional control
, the estimated dosing time per batch can be calculated with the following formula:
Rate
Flow
Scale
Full
Size
Batch
seconds
2
(seconds)
Time
Dosing
+
=
With
on/off control
, the estimated dosing time per batch can be calculated with the following formula:
Flow
Instrument
Maximum
Size
Batch
second
1
(seconds)
Time
Dosing
+
=
Note that with on/off control, the only way to affect the dosing time is by changing the batch size, because the maximum
instrument flow cannot be changed. With proportional control, the measuring range of the instrument can be rescaled.
The formulas above depict rough estimations of the expected dosing times. The extra time (2 seconds for proportional
control, 1 second for on/off control) is determined experimentally, based on observations made while setting up CORI-FILL
using FlowPlot.
5.2
Process conditions
When setting up the instrument for batch dosing, the following considerations are critical for obtaining accurate dosing
results:
·
Prior to starting batch dosing, adjusting the zero point of the instrument at actual process conditions is recommended
(see
).
·
The inlet pressure should be appropriate and stable. Too high a pressure will cause batch size overshoot, too low a
pressure will result in not reaching the configured batch size within an acceptable time frame.
·
For liquid dosing, the liquid should not contain any gas bubbles. Gas bubbles act as an 'expansion vessel', destabilizing
the flow rate and slowing down response times. Using a degasser is recommended, especially with very small batch sizes
and/or times (in the order of mg/ml and ms respectively).
·
The amount of piping, reducers, connections and T-parts should be limited to the absolute minimum.
·
Tubing/piping size should be appropriate to the flow rate.
5.3
Parameter settings
Preparing the instrument for
CORI-FILL™
batch dosing involves setting a number of parameters, in order to determine the
dosing characteristics:
1.
(volumetric flow or mass flow)
2.
3. optimization
a.
b.
c.
This section concentrates on configuring the instrument using FlowDDE and FlowPlot. Guidelines given for setting
parameter values are based on best practice. For some parameters, the optimal value depends on a number of factors, such
as the instrument type, specific dosing requirements and operational circumstances.
For the most part, configuration can be done in the
Instrument Settings
function in FlowPlot. In order to enable
communication between FlowPlot and the instrument, the
Control Mode
of the instrument has to be set to RS232
communication (see
).
Extensive information about the installation and usage of FlowPlot can be found in the FlowPlot manual (document
9.17.030), which can be downloaded from
http://www.bronkhorst.com/en/downloads
.
