A versatile single-screw-extruder system designed for magnetic resonance imaging measurements

Abstract

A versatile system has been developed for magnetic resonance imaging (MRI) measurements, in which a ceramic barrel/outer cylinder (0.04 m internal diameter) can be configured either as a single-screw extruder (polyetheretherketone (PEEK), length to diameter ratio 4.575, root diameter 0.03 m), or as a concentric-cylinder Couette device (PEEK, length 0.156 m, inner cylinder diameter 0.03 m). A second channel in the sample inlet allows two streams of fluid to be pumped simultaneously through the system for mixing. The shaft rotation speed can be set between 5 and 1200 revolutions per minute (rpm); the barrel and sample feeder can be separately thermostatted to ±0.2 °C in the range of −10 to +60 °C via coolant jacket systems; samples with viscosity up to 10 Pa s can be pumped at rates up to 36 l h−1. This enables studies to be conducted with the system configured as a Couette device to provide knowledge of the rheological properties of complex fluids before more complicated studies of their flow and mixing with the system configured as a single-screw extruder.