An installation for increasing the intrinsic viscosity of a polyester material by solid phase polycondensation (SSP) comprises a heatable reaction container (2, 2′) in which the polyester material (P) can be left to reside at a predetermined thermal treatment temperature for a predetermined residence time until it has reached a desired intrinsic viscosity, and a cooling container (6, 6′) arranged downstream of the reaction container, the cooling container (6, 6′) being designed for cooling the polyester material discharged from the reaction container to a first cooling temperature which is lower than the reaction temperature. Downstream of the cooling container (6, 6′), a polyester material separator (7) is arranged which is designed for diverting the polyester material flow to a polyester material processing machine (8) and/or to an intermediate storage container (10).