Sampling in the plastic recycling process
Demand for recycled plastics is rising, driven by statutory quotas and the demands of a functioning circular economy. At the same time, expectations regarding the quality of the material are increasing. Plastic flakes from the recycling process are naturally subject to variation—for example, from foreign polymers, residual moisture, or metallic contaminants carried over from upstream processing. Continuous, automated quality control is therefore essential to ensure that the recycled material can reliably be incorporated into new products.
In this case, plastic flakes should be sampled directly from a pneumatic conveying line. The challenge: the material moves through the pipeline in an air stream, so a cross-sectional sample cannot be taken here as it can with a free-falling material stream. Appropriate technology solves this problem: two samplers, together with a suction unit, ensure that the sample is fed directly to a laboratory instrument via a connecting hopper for analysis. In addition to the sampling system itself, we built an extended platform with a cabin to create a dedicated workspace for sample analysis.
The automation technology integrates the analyzer directly into the process control system: the measured values are transmitted via a PLC interface to the higher-level process logic, where they are available for automated control decisions.
Our samplers are custom-engineered for each application, yet consistently suited to heterogeneous, granular bulk materials—requiring minimal space and remaining low-maintenance even in continuous operation.
A few facts about our project:
- Sampling in downpipe systems with special pressure conditions
- Number of Roskopf employees involved in the project: 6—ranging from technical project management to design to the installation team
- Over 60 meters of pipe plus additional materials were installed during the project
