Weigh Belt Feeders are used to feed bulk solids at a controlled rate into the process. Rugged design makes them ideally suited for use under adverse conditions. As the product is fed onto the synchronous speed weigh belt, the weight of this material is instantaneously sensed and transmitted to the feeder’s controller. In turn, the controller modulates the variable speed drive of the feeder to maintain the precise feed rate as selected. A closed loop PID control system ensures precise control over the rate of flow of material. The system consists of a Control Panel, Load Cells, and an AC motor with gearbox.
Weigh Belt Feeders
Salient Features / Technical Specifications
Specifications:
- Accuracy: ±0.5% or better.
- Output Capacity: 2.7 TPH continuous.
- Controls: Weigh Belt Feeders utilizes multiprocessor controllers with inbuilt PID’s, specifically developed to provide unparalleled weigh feeder performance.
- Volumetric Mode of Operation: Weigh Belt Feeders are equipped with a manual mode of operation whereby the unit may be operated strictly as a volumetric feeder if ever required. The weigh belt, in volumetric operation, is used for conveying purposes only.
Controller specifications:
The controller is equipped with a powerful CPU including integrated digital I/O’s.
Strain Gauge module with 24-bit ADC.
The controller is equipped with Operator panel, which helps visualization of tasks.
Communication interfaces such as Ethernet or RS232 also provided. These controllers are tested and certified to perform in harsh industrial environment including excessive shock, high temperature and continuous operation.
The Unit provides the following output:
- 4-20mA current output corresponding to the measured rate.
- P.F contacts for totalizer output, Panel Healthy, Panel Fault.
- LED indications are provided for Belt On, Totalizer Output, and Over Load.
- Provision for sensor inputs for Belt Sway and Material Starvation is provided.
Displayed Parameters:
- Belt load in Kg/meter.
- Belt speed in Meters/min.
- Measured rate in Tonnes/hr.
- Totalized quantity in Tonnes.
General specifications:
WBF – TEA (Green or Withered leaf)
| Conveyor Type | Belt, ~ 2250mm, Endless |
| Weighing | Idler Weighing System |
| Belt | 3 ply |
| Drive | Direct Shaft Drive |
| Product | Tea leaves |
| Bulk Density | 180 kg/m3 ** TBA |
| Design Capacity (TPH) | 3 TPH |
| Grain Size | **TBA |
| Moisture | 80 to 82% Wet basis |
| Feeder Length in mm | 2250 |
| Width in mm | ~ 800 mm to 1000 mm |
| Motor Type | AC Motor Gear Box Unit |
| Make | ABB/Bonfiglioli |
| Supply Voltage | 3 phase, 415V, 50 Hz |
| Power Rating (kW) | ~ 1.5kW |
- N.B. **TBA – To Be Advised
Controller specifications:
The controller used is equipped with a powerful PCC CPU including integrated digital I/O modules. The load-cell module is a plug-in module with 24-bit ADC.
Technical Data:
Display: Colour HMI
Digital Inputs: 12
Digital Outputs: 12
Strain Gauge Modules: 1
Interfaces: Ethernet
Protection Category: IP65
Encoder specifications (Technical Data):
Pulse Count (ppr): Max. 2500
Output Type: Push-pull, Incremental
Operating Voltage: 4.75 to 30 VDC
No Load Supply Current: Max. 80mA
Operating Current: Max. per channel 40mA, short circuit proof
Rise Time: 250 ns
Protection Degree: IP 50
Shock resistance: DIN EN 60068-2-27, 100g, 3ms
Vibration resistance: DIN EN 60068-2-6, 10g, 10-2000Hz
Operating Temperature: -20°C to 60°C
Mechanical specifications:
Housing Material: Aluminium, Powder Coated
Flange: Aluminium 3.1645
Shaft: SS 1.4305
Mass: (Approx.) 220gms
Rotational Speed: Max. 10000 per minute
Moment of Inertia: < 5gcm2
Starting Torque: < 1.5Ncm
Shaft Load: Axial – 30N, Radial – 50N
Load Cell specifications:
Sensitivity: 2mV/V
Rated Excitation: 10VAC or DC
Max. Excitation: 15VAC or DC
Bridge Resistance: 350 Ohms
Insulation Resistance: 1000Meg Ohms
Zero Balance: +/- 0.1mV
Non-Linearity: <0.025% of FS
Hysterisis: <0.020% FS
Non-Repeatability: <0.010% FS
Creep (30min at Nom Load): <0.020% FS
Operating Temperature: -20Deg C to 70Deg C
Safe Overload: 150%
Ultimate Overload: 300%
Protection Class: IP68
MOC: Stainless Steel
Optical Signal Isolator
Technical Data – Current Repeater/Driver Dual Channel Isolator:
The current repeater is a fully floating isolator for standard 4-20 mA instruments. Each channel works as a DC isolator with the inputs galvanically isolated from the outputs. Typical applications include driving I/P converters and isolating 2-wire transmitters. Power Supply Loop powered (not intrinsically safe).
| Nominal voltage | 12-35 VDC |
| Input voltage (Vin) | 10-35 VDC |
| Input current (Uin) | 4-20 mA |
Output voltage:
10 V < Vin < 26.1 V 0.9 x Vin – (0.23 x current in mA) – 0.7
Vin > 26.1 V 23 V – (0.23 x current in mA)
Output current: 4-20 mA
Short circuit current ≤ 65 mA @ Vin>26.1 V
Transfer characteristics:
Calibrated accuracy ±20 μA for 1 kΩ load @ 20ºC (includes linearity and hysteresis)
Temperature drift ≤ 2 μA / ºC