Abstract: Apparatus for diluting and activating polymer molecules includes primary polymer dilution and activation apparatus, secondary dilution apparatus, and apparatus for diverting a desired amount of dilution water around the primary dilution and activation apparatus to the secondary dilution apparatus. The primary dilution and activation apparatus includes a cylindrical first processing zone in which the polymer and dilution water are initially mixed. The first processing zone subjects the polymer molecules to relatively high shear conditions for a relatively short period of time, after which the solution passes into a second cylindrical or annular processing zone in which the solution is subjected to continuously decreasing shear forces over a longer period of time. When the solution leaves the primary activation apparatus, it flows into the secondary activation apparatus, which is a static mixer.