o Drop test of belt weigher is difficult without load cell mounted circuit hoppers.
o If the drop test is taken for shorter duration less than 10 minute, test results
are not reliable,
o Online verification of system accuracy is not possible unless significant deviation
is observed in the feed rate,
Important Notes
o The drop test without calibration bin is observed inaccurate as continuous
running at constant running of the belt weigher at fixed flow rate gives
more accurate test results,
o Weighing hopper is very important for belt weigher operation and
performance which helps in on line calibration as well as performance
monitoring.
Measurement Principle Bin Weigher
o The bin weigher is on line weighing measuring machine used to monitor
total weight of materials in the bin.
o The bin is mounted on load cells. This load is converted into total weight
(in Tons) with the help of signal processing unit.
o The bin may be with single load cell (only for level measuring purpose, less
accurate system for weight measurement), or may be with 3 load cells (for
circular bin) & 4 load cells for Rectangular bins.
o For accurate weight measurement, 3 or 4 load cells, based on bin design,
are installed.
o Since this is static type of weighing system, it gives more accurate compared
to Dynamic weighing measuring system like Weigh feeder & Belt Weigher.
Accuracy of bin weigher is +/-0.1%, for 3 load cells based system.
o Test Weights of min. 10% of total capacity of the system) are used for
calibration of bin.
Measurement Principle Solid Flow Meter
o The solid flow meter is on line weighing measuring machine used to monitor
flow rate of fine solid materials.
o The system consist a Measuring plate mounted at a definite (slanted) on a
shaft. The Shaft both ends are connected to load cells. The fine material
falls directly on plate. This falling impact is transferred to load cell. Then it is
converted into flow rate with the help of signal processing unit.
o Accuracy of Solid flow meter is ±1.5 to 2%.
o Online verification of system accuracy is not possible unless significant
deviation is observed in the feed rate.
Factors affecting the equipment performance
o Any coating of material on plate results in erratic reading.