The DP crystallizer includes double propellers and a fixed draft tube inside. A one-body reverse-angle impellers is equipped inside and outside the draft tube, and creates a reverse directed flow in the same rotational direction. Even with a low rotation, a circulation amount that is larger than that of one with a single impeller is made possible, the stirring flow of equal density makes no wasted space, and grained crystallized products can be created. We have suitable test equipment to respond to our customers' various needs, including sanitary specifications.