Belt weighfeeders with controlled belt speed are belt-assisted feeders whose belt speed is adapted so it attains the nominal delivery rate.

Since the same amount of material is not always transported on the conveyor belt, the belt speed must be varied to achieve a constant feed rate per unit of time. The weight of the material transported is determined by weighing the belt load and measuring the belt speed. Variable speed conveyor with uniform profiled loading. Belt speed is adjusted to maintain desired  material flow rate. Finally to get the totals material conveyed.

Depending on design, belt weighfeeders have delivery rates ranging from several kilograms to several hundred tons an hour.The weighfeeder is able to control the flow of material into or out of a process, without interruption or disruption to the flow. The Milltronics BW500 PID, Omron speed sensor and Siemens load cell, VFD and motor are the main player in the control .

P = Proportional Control (Gain)
Adjusts the control output based on the difference between the set-point and the process value (rate or load).

I = Integral Control (Automatic Reset)
Adjusts the amount of control output to eliminate the offset caused by the P term

D = Derivative Control (Pre-Act or Rate)
Adjusts the control output based on changes in the magnitude and direction of the change in error.

EHC Weighfeeder Announcement:
Successful installation of Weighfeeder to our Danish client with production base in Malaysia, a market leader of white cement and dry-mix products during 2021 - 2022.

• Weighfeeder for Gypsum weighing
• Weighfeeder for Limestone weighing
• Weighfeeder for Clinker weighing

EHC Scope of Works

• provision and installation of weighfeeder + weighfeeder support structure + discharge hopper(dumping chute)
• provision 3 copies of Electric Circuit Drawing
• termination of load cell
• static calibration
• provision and installation of outlet chute + platform and footing + controller + inverter
• electrical wiring connection work for drive and controller
• testing and commissioning
• attendance during dynamic test run of the weighfeeder for minimum 5 hours per unit with actual materials.

Challenges: To address space constraint issue, EHC agreed and confirmed to move centre point of inlet to discharge from 1900mm to 1300mm and to ensure platform + platform footing are installed as specified. Initial concern on inlet chute dimension was addressed.