Requirement
The machine is part of a plant for the mechanical extraction of plastic granules from storage silos, consisting of two big bag filling stations.
The goal is to fill the bags with bulk product and ensure consistent weight across all big bags through repeatable weighing.
Focus
Stawimpianti s.r.l. is an Italian company that has been designing, building, and installing complete systems for storing, batching, and conveying solid bulk raw materials, in powder, granule, or flake form, for over 30 years.
Our solution
For the weighing and batching system we used:
- 3 FTP 1000 shear beam load cells;
- 3 T12FTAGP mounting kits;
- 1 CE41N ABS junction box;
- 1 TLM8 PROFINET IO weight transmitter.
How it works
The operator hooks the bag’s straps onto the hooks and starts the automatic cycle from the power panel. A fan integrated into the machine inflates the bag so that the incoming material has as much space as possible.
Once the bag is inflated, the loading screw conveyor begins unloading the plastic granules from the silo and filling the big bag, while the load cells continuously weigh the bag.
The load cells are installed above a rotating slewing ring, positioned in the machine’s upper operating unit, at the top of the bag where the suspension hooks are located.
Focus
The rotating slewing ring is a large structural bearing that makes it easier for the operator to hook the 4 loops of the bag without physically walking around the machine.
The fixed structure becomes a rotating station, making the filling operation safer, more convenient, and faster.
The load cells are connected in parallel to the CE41N ABS junction box, which has an IP67 protection rating that is essential for shielding the board from dust and moisture.
The junction box is connected to the TLM8 weight transmitter, located in the power panel away from the structure, which transmits the weight data to the PLC via PROFINET IO fieldbus.
When the load reaches the previously set setpoint value, the PLC sends a command to the TLM8 which, via its relay contacts, triggers the closure of the filling valve, and the full bag is ready to be unhooked.
The added value
The machine’s automatic system supports and enhances operator workflow: filling operations are faster, safer, and more efficient.
The FTP 1000 load cells offer an excellent quality/price ratio, are reliable, and have a high protection rating.
The T12FTAGP mounting kit ensures precise and accurate weighing: it features a rubber-coated stainless steel joint that compensates for structural unevenness and dampens vibrations generated by the hydraulic power unit and other moving components.
The TLM8 PROFINET IO weight transmitter ensures easy, reliable, and fast communication: the robust fieldbus signal transfers the load cell signal to the PLC securely, even when the PLC is located far from the weighing system.
The load cells, in combination with the TLM8 weight transmitter, ensure consistent bag weights leaving the facility, eliminating measurement errors.
