A melt-phase polymerization reactor with the novel geometry of two helical solid-tube impellers rotating within a tank, consisting of two intersecting cylinders, was designed and constructed. In order to evaluate the performance of the system, mixing times and power consumption were measured using a viscous Newtonian model fluid (glucose syrup) in place of the polymer melt. The mixing regime was laminar in all runs, The mixing time at various impeller speeds was estimated by injection of a tracer dye (crystal violet), followed by fluid sampling and visible spectrophotometric analysis. A dimensionless mixing time of k(m) = 104 +/- 36 was obtained. The power draw required to move each impeller through the fluid at various impeller speeds was measured, and a power constant of k(p) = 1156 +/- 70 was obtained. The system appeared to outperform the conventional single helical ribbon impeller in terms of mixing time, but was less energy-efficient, as indicated by the larger power constant. The power constant value lies between values previously reported in the literature for conventional helical impellers and values reported for other types of polymerization reactors with different geometries.