Agitator having variable pitch

The utility model relates to a mixer having a variable pitch. The top of a reaction kettle is provided with a rotating disk connected with a power device. The central position of the rotating disk is provided with a mixing spindle, the tail end of which is connected with a mixing vane. The utility model is characterized in that a vane transmission shaft is installed in the spindle; the tail end of the transmission shaft is connected with the mixing vane through a bevel gear set and the top end is connected with the power device installed on the rotating disk. The power device is composed of a motor, a speed reducer, a driving bevel gear and a driven bevel gear, wherein the driving bevel gear is connected with the speed reducer; the driven bevel gear is connected with the vane transmission shaft. When the mixing spindle drives the mixing vane to rotate, the utility model drives the mixing vane at the bottom to deflect a certain angle through adjusting the rotation angle of the bevel gear on the power device arranged on the top end of the transmission shaft, which causes an included angle between the mixing vane and materials to be changed so as to adjust the size of force born by the mixing vane. The utility model is especially suitable for solid and liquid mixing reaction.