Apparatus for continuous tempering of fat-containing, chocolate masses

An apparatus for the continuous tempering of a fat-containing, chocolate mass comprising, a cylindrical tempering column having a cooling stage and a subsequent reheating stage through which the mass flows, each stage containing a plurality of mass chambers interconnected for the flow of the mass separated by intermediary heat exchange chambers, said heat exchange chambers being adapted to absorb heat from the mass chambers during flow of cooling media through the heat exchange chambers in the cooling stage and to submit heat to the mass chambers during flow of heating media through the heat exchange chambers in the reheating stage, a drive shaft arranged for rotation about an axis located centrally of the column, a mixing and stirring element located in each mass chamber and adapted to be rotated by said drive shaft, each of said mixing and stirring elements having at least one radially extending plate shaped arm and a plurality of upper and lower plate shaped mixing blades extending in an essentially axial direction from one upper and lower side of said arm, respectively, said upper mixing blades extending radially outward in a direction opposite to an outward radial extension of said lower mixing blades with respect to the direction of rotation of the mixing and stirring element, wherein said upper and lower mixing blades have, at an end remote from said plate shaped arm, horizontal surfaces which are spaced axially from inner wall surfaces of upper and lower horizontal walls, respectively, of the mass chambers to provide shear gaps between said surfaces though which gaps the mass flows when the mixing and stirring elements are rotated in the mass chambers and wherein the total surface area of the plate shaped arm and of the mixing blades decreases gradually in a direction radially outward toward a peripheral end of the arm.