hydraulic piston pump or solids pumps, hydraulic power pack driven by the hydraulic cylinders, hydraulic cylinders advance the delivery cylinder, the delivery of materials to the output of the cylinder pipe. Generally divided into single and double piston plunger, typical representatives of Germany four Putzmeister solids pumps, which are: EKO single piston pump, KOS, KOV, HSP three kinds of double-piston pump. The pump belongs to positive displacement pumps, especially for high solid content, long-distance pipeline viscous material, the advantage is to run very stable and reliable, but noisy, delivery pressures up 130Bar, the displacement of up to 0.5 to 500 cubic meters / hour. Widely used in sewage treatment, solid waste treatment, mining and metallurgy, dredging, dredging, petrochemical, power plants, cement industry and other fields.