Abstract: A film evaporator formed by a cylindrical body section (50) with a heating jacket (53) and angled scraping blades (84) mounted on a rotatable shaft (76) to move the thickened material downwardly through the evaporator. Below the body section (50) is an inverted frusto-conical section (62) containing inclined scraping blades (86) also mounted on the shaft (76) and a smaller diameter lower body section (64) through which the thickened product can be discharged by a screw (93) of opposite hand to the scraping blades (84). The screw (93) is carried on a lower shaft (88) which is journalled to the shaft (76) so that the shafts can be rotated independently and in opposite directions.