Twin screw extruders excel in positively conveying high viscosity fluids. By contrast, other equipment may have torque limitations or insufficient conveying capabilities, resulting in material degradation and long changeover between product grades.

The design flexibility of NFM/WE extruders allows environmental considerations to be addressed as part of the process.

Our twin screw design has the shortest residence time of any devolatilization device (less than three minutes, typical). Changeovers are faster, thermal history is minimized, and product is less likely to be degraded.

Twin screw extruders can increase temperature by controlled shearing of the polymer solution. Other devices rely on surface renewal, pressure, and conductive heat transfer for devolatization.

Gel information, discolored product, or broad molecular weight distributions are reduced by the design of the twin screw, small volume and positive conveying characteristics.

For highly concentrated polymer solutions (less than 1% solvent), twin screw extruders are ideal for renewing surfaces through the use of multi-flighted screw elements and high screw speeds.

NFM/WE's counter-rotating, non-intermeshing screw design has the largest free volume capabilities of any twin screw extruder manufacturer for containing foaming melts (typical of 30%-50% solvent concentrations). This extra free volume also means that we can provide longer residence time under each vent reducing tendencies for vent flow and overall better performance and operability.

Our extruder design offes longer, wider vents allowing vapor velocity to be lowered and the entrainment of the polymer to be reduced accordingly. Larger vents also mean higher vapor removal capability, due to low velocity when removing large amounts of solvent and extra residence time under vacuum removal of the final parts per million of solvent.

Our design allows the barrel to be open for a vent over a full diameter directly over the center of the screws (and wider in some cases). The screws' rotation acts to pull polymer down in the vents, thus resisting vent fouling or flow.

5,000-5,000,000 centipoise @ 100 reciprocal seconds, 20-80 Mooney Viscosity.

30% and higher to the extruder.

Temperature is controlled by screw design, screw speed, and barrel temperature regulation. The use of water stripping may also provide some cooling capacity.