Movacolor is introducing the MCS Continuous Loss-in-Weight Blender, a new continuous loss-in-weight gravimetric dosing system designed for extrusion processes in which throughput can vary significantly and frequently over short periods. The solution is targeted primarily at applications where melt pump disturbances cause sudden fluctuations in material flow, leading to unstable line operation and material losses.
In processes such as filament yarn production, interruptions in melt pump operation result in frequent and sharp changes in throughput. These fluctuations lead to unstable material flow, failure to maintain the specified blend ratios, increased scrap and higher raw material costs. Conventional continuous loss-in-weight systems do offer high accuracy, but their response speed is often a limiting factor when extruder demand changes rapidly.
The MCS Continuous Loss-in-Weight Blender has been developed specifically to address this issue. The system design enables rapid adjustment of dosing speed while maintaining a stable material level, which translates into consistent blend ratios even under dynamically changing line throughput.
A new configuration of gravimetric dosing
Unlike traditional in-line systems where dosing units feed material directly into the machine inlet, the MCS Continuous Loss-in-Weight Blender uses a weighing hopper located beneath the dosing units. All dosing units feed into a common hopper equipped with a material level sensor.
Thanks to this configuration, the system continuously knows and monitors the exact hopper capacity and target material level. This allows very rapid adjustment of dosing speeds to maintain a stable level in the hopper, even during sharp throughput changes. As a result, the feeding system operates stably and blending parameters remain consistent in conditions where conventional solutions struggle to respond quickly enough.
Key benefits of the system
According to the manufacturer, the MCS Continuous Loss-in-Weight Blender provides a range of operational benefits in extrusion processes exposed to dynamic throughput changes:
- fast response to line throughput fluctuations,
- rapid dosing corrections to maintain a stable hopper level and constant feeding performance,
- reduced scrap and material losses,
- fewer off-spec products during pump interruptions and ramp-up phases,
- lower material costs and improved return on investment due to better dosing control and reduced overdosing,
- operation maintained closer to the setpoint,
- particular suitability for applications such as filament yarn extrusion, where throughput changes frequently.
Klaas Talsma, product manager at Movacolor, also highlights the capabilities of the new solution at low line throughputs and low masterbatch addition levels. He indicates that the system remains stable and accurate even under demanding processing conditions.
"Even at very low extruder capacities of 20–30 kg/h and masterbatch additions of just 1%, the system remains stable and accurate. In addition, the high-temperature-ready design makes it fully suitable for PET processing, opening up applications that are not reliably supported by alternative solutions."
