A fluid pump for pumping fluidized materials comprises a motor, a material pump, and a closed-loop pressure hydraulic system interconnecting the motor and the material pump. The closed-loop hydraulic system further comprises a hydraulic pump, a pressure regulator, an impeller, and an expandable fluid...http://www.google.fr/patents/US6808121?utm_source=gb-gplus-shareBrevet US6808121 - Fluid pump
