Abstract: An apparatus and process for removing undesired monomers and oligomers from polyamide melt at subatmospheric pressure by passing steam through the melt to absorb the undesired components and carry them away. Various constructions are disclosed for vigorously intermixing the gas with the melt in which the gas is passed through a foraminous surface over which a thin film of melt flows, and a rotating agitator, spaced less than 50 mm from the surface, mixes the gas with the melt film. In a preferred form of the invention the rotating shaft comprising the agitator carries screw threads and serves as a conveyor for discharging treated melt from the pressure vessel in which the process is carried out.