Abstract: Improved apparatus for mechanically stirring a quench-cooled subfluidized particulate bed of polymerized monomer lowers lumping of polymer particles by using substantially contiguous paddle stations disposed along the drive shaft within the reactor in combination with a plurality of sub-stations in at least one paddle station class, each sub-station having a width along the shaft of no more than 50 percent of the total width of the paddle station, and sub-station paddles attached to the shaft at each sub-station so as to sweep through the particulate bed.

Abstract: Method and apparatus are described for continuous vapor phase polymerization of a polymerizable monomer or mixture thereof to produce normally solid polymer substances in two or more serially disposed vapor phase polymerization reactors, each containing a quench-cooled subfluidized particulate bed of polymerized monomer. More specifically, method and apparatus for transfer of polymer particles between high pressure, reactive gas-filled, continuous, vapor-phase polymerization reactors while maintaining each at independently selected operating conditions.