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FLOW MEASUREMENT + INSTRUMENTATION
Measuring high viscous resins
Production processes in manufacturing of abrasives and superabrasives
require precise dosage of even high viscous resins (e.g. 1 500 cP). Kob-
old Instrumentation, represented locally by
Instrotech
, was asked to
look into, and supply a solution.
The application image below shows one dosing skid in such applica-
tion. Each skid comprises of the following components:
• Main tank
• Secondary tank with low level alarm, always ensuring enough prod-
ucts and no air in the circuit
• Manual valve to close the circuit
• Peristaltic pump
• Oval Wheel Flowmeter
• Pressure Switch (safety against high pressure)
• 3-way valve (for manual or automated operation)
• Outlet pipes for manual product collection
At higher viscosities and depending on temperature fluctuations, the
peristaltic pump (positive displacement pump comprising of flexible
tube and of roller(s) displacing the medium from one end of the flexible
tube to the other) is not able to displace the medium completely. This
means that some part of the medium flows back through the flowmeter
resulting in error readings. In addition, the operating pressure developed
by the small sized peristaltic pump is quite low.
Oval wheel flowmeters model DON can be provided with special cut
rotors reducing the pressure drop by 50%. Choosing the optional Quad
Hall Sensor Dual Pulse Output provides two out of phase pulse outputs
‘A’ and ‘B’, so that net flow rate ‘A-B’ may be computed correctly by the
PLC. Net flow rate could also be computed using ZOK-Z3 electronic with
a pulse discriminator in between. With these features, Kobold was able
to solve all problems associated with this application and conduct very
fine dosing of resins, resulting in an improved repeatability and quality of
the finished abrasives.
Enquiries:Tel. +27 (0) 10 595 1831 or email
sales@instrotech.co.za