An unusual device for mixing two viscous materials or adding powder or fiber to a polymer consists of two tightly fitting cylinders, one inside the other, with the outside one turning. "Windows" in the inner cylinder create drag flow and extensional mixing as material flows past.

An unusual device for mixing two viscous materials or adding powder or fiber to a polymer consists of two tightly fitting cylinders, one inside the other, with the outside one turning. "Windows" in the inner cylinder create drag flow and extensional mixing as material flows past. Engineers at the Commonwealth Scientific and Industrial Research Organization (CSIRO) in Victoria, Australia, invented the concept four years ago (U.S. Patent 7121714; Oct. 17, 2006) and have experimented with dispersing nano-particles and fibers into urethane and epoxy. Called the Rotated Arc Mixer (RAM), the device could be used as a cylindrical section attached to a melt pump to combine polymer flows or to add powders or fibers to polymer. It could even potentially be modified as a mixing section for a single screw extruder, CSIRO says. The test cylinder is about 1.5 ft long and 15 mm diam. The device can also be partitioned so that two materials are combined and then after a break, another material is added. Tel: +61 (3) 9252-6083 . www.csiro.au