The screw sampler is designed for the automatic and representative sampling of dry, free-flowing and fine-grained bulk materials conveyed through gravity-fed pipelines or pipelines operating at low overpressure.

Its multi-chamber design enables reliable sampling even from pipelines containing a static material stream. Before each sampling cycle, residual material is automatically purged from the screw to prevent contamination of the subsequent sample and to ensure representative sampling.

At the beginning of the sampling cycle, the screw rotates in reverse to discharge any residual material through the purge outlet. Once the screw has been cleared, the direction of rotation is reversed and the screw advances into the material stream.