Pretreatment device of stacked spiral sludge dewatering machine

The utility model provides a pretreatment device of a stacked spiral sludge dewatering machine, and belongs to the field of sewage treatment. According to the technical scheme, the device comprises a material storage box, an overflow plate is arranged at the bottom in the material storage box and divides the material storage box into a material mixing tank and a buffer tank, the upper portion of an inner cavity of the material mixing tank is communicated with a flocculant adding pipeline, and the lower portion of the inner cavity of the material mixing tank is communicated with a sludge inlet pipeline; the lower part of the inner cavity of the buffer tank is communicated with a sludge return pipeline, a controlled valve is arranged on the sludge return pipeline and is controlled by a liquid level detection device, and the left part of the inner cavity of the buffer tank is communicated with a sludge outlet pipeline. Compared with a traditional stacked screw type sludge dewatering machine, the liquid level det