Belt Weighers are commonly used for moving bulk materials in Process Industries. With the advent of this fast mode of transportation, accounting the quantity of material transferred assumes great importance. Since weight remains as the most reliable index of material accounting and can be measured directly and precisely, designers can offer accurate weighing systems to maintain higher accuracy and better accountability in the process.
Major advantages of NGE belt weighers :
1. The system uses strain gauge type precision loadcell which have negligible deflection hence higher accuracy is achieved.
2. Two Idlers are used (using 4 loadcells) for weighing hence high resolution with respect to dead load of the belt and idlers.
3. No mechanical levers are used to sense the belt load. Hence, no inaccuracy on that account.
4. Digital (Proximity) Speed Sensor designed to generate sufficient pulses even at very low belt speed.
5. High speed ADC is used to have faster response.
6. Self diagnostic facilities
7. Tare values of the belt programmed for different intervals to derive material weight.
8. RS 232 / 485 port available to hook on to computer.
Principle of Operation:
The material passing over a Belt Conveyor exerts a downward force proportional to its weight. The product of this force and the speed of the belt is the rate of flow, the unit being Kg/min. or Tonnes/hour.
Taking a section of unit length between ‘aa’ and ‘bb’ on the belt (fig. above), the reaction ‘R’ at the centre of that section equals the weight of the material including the belt weight, on that section. The tension of the belt ‘T’ has got no influence on reaction ‘R’ if ‘T’ and ‘R’ are mutually perpendicular.
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Let the weight between ‘aa’ and ‘bb’ (unit length) = w kg / mtr.
Let the speed of the Belt = s mtr./min
Therefore, material flow / min. = w x s
The rate of flow w x s integrated over a period of time gives the total quantity of material transferred over that time.
The load coming on the idler is measured by load cells. In “NGE” make belt weigher, two sets of idlers are weighed to get higher output and accuracy.
The speed of the belt is measured by speed sensors. For higher speeds, AC Speed Sensor is used and for lower speeds, Proximity based Speed Sensor is used. The rate signal integrated in time gives the quantity of material transported during that time.
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Scope of Supply :
01. Loadcell of adequate capacity with mounting bracket for idlers.
02. Speed Sensor
03. Electronic Unit
04. Remote Unit
05. Calibration Chain / weight
06. Cables
07. Junction Box
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