Rotary processors and method for devolatilizing materials

Abstract

Novel rotary processors and devolatilizing methods which provide extremely efficient devolatilization of materials, including viscous and visco-elastic materials and which involve a devolatilizing stage including a rotatable element carrying a plurality of annular channels and a stationary element providing a coaxial closure surface operationally arranged with the channels to provide enclosed processing passages. Each passage of the devolatilizing stage includes inlet means, outlet means and a channel blocking member all associated with the stationary element and arranged and adapted so that material fed to the inlet can be carried forward by the rotatable channel walls to the blocking member for discharge from the passage. The passages are interconnected by material to transfer grooves formed in the closure surface and operationally communicate with a vacuum source to provide a highly efficient devolatilizing stage. The novel devolatilizing stage is characterized by features which provide control of the processing volume available within the passages and of the transfer volume available within the transfer grooves. These volumes may then be coordinated with other processing variables to effect a foam devolatilizing mechanism in which nucleation of bubbles of volatiles within the material, bubble growth and bubble rupture occur during substantially plug-flow movement alternating with non-pressurizing shearing within the novel devolatilizing stage.