Two-Stage Machine Promises Better Mixing.

The new Ultima Compounder from Farrel, Ansonia, Conn., combines a two-stage continuous mixer and a single-screw discharge extruder on a unitized support frame. More versatile than Farrel's original continuous mixer, the unit features extra mixing length and residence time and what the supplier terms a vastly expanded processing window. The counter-rotating mixer employs rotor speeds to 1000 rpm. Clearances between the rotors and the chamber walls are different in the two stages of the mixer. In the second stage, a variable orifice can be adjusted to permit increased dispersive mixing, vacuum venting, or downstream addition of fiber, additives, or resins. Similar to Farrel's CP Series mixer/extruder combinations, the Ultima is designed so that the mixer and extruder can operate independently. Applications include mixing nanocomposites and wood flour.