| abstract |
An extraction tube for the continuous removal of low molecular weight components of polylactam granules by means of hot water by the countercurrent principle of operation, the water being fed upwardly and the granules downwardly, the tube being provided with inlets and outlets for the granules and the water and exhibiting baffles within the tube, wherein there is provided, within the tube, a heat exchanger which n A. divides the tube into two sections bearing a ratio to each other of from 50:50 to 85:15 by volume, the smaller section being at the top of the tube, n B. exhibits ducts for the granules over the entire cross-section of the tube and n C. has top surfaces facing the stream of granules, which surfaces are inclined toward the ducts to an angle β to the horizontal, this angle being equal to or greater than the angle of repose of the granules but less than 90°, n Further similar heat exchangers being provided beneath said heat exchanger if desired. |