Bimanual Manipulation in a Curve Editing Task

Slurry consisting of water and solid material is fed to a plurality of supply chambers arranged in parallel to each other by a low pressure slurry pump, and the filled slurry is transferred to a transferring pipe under liquid pressure of a high pressure driving liquid pump. Also, to the upper and lower portions of the supply chambers are connected driving liquid supply/discharge pipes and slurry supply/discharge pipes having valves. The valves are selectively opened/closed in accordance with a detection of a float position within each supply chamber to thereby feed the slurry continuously under pressure. Upon the slurry pressure feeding, the valves connected to the supply chamber lower portion are prevented from closing due to a packing condition.