Abstract: A continuous-operation extractor for the solvent extraction of low-molecular weight compounds for a solid, e.g. granular polyamide, comprises an upright housing formed internally with vertically extending pipes beneath each of which a steam nozzle opens. Deflectors are provided above the upper ends of each pipe and an overflow conducts the solids downwardly from one extractor stage to the next. A solid inlet communicates with the uppermost extraction stage and is provided with inclined perforated baffles while below the lowermost stage a float-controlled valve regulates the steam inlet.