Development of a centrifugal pump with thick blades

We have developed a centrifugal blood pump with thick impeller blades (60% of pitch) to obtain a small tip clearance. An unshrouded impeller with 6 ba ckward curved thick blades was used to reduce the dead zone between the shr oud and upper casing, A streamline angle in volute was uniform in circumfer ential direction by continuity and angular momentum conservation. To prove the effectiveness of small tip clearance, performance and hemolysis tests w ere conducted on pumps with a tip clearance of 05, 1.5, and 2.0 mm at exit with the blade thickness of 60% of pitch, and with that of 1.0, 2.0, and 2. 5 mm at exit with the thickness of 40% of pitch. The results showed that th e smaller the tip clearance, the better the hydrodynamic and hemolytic perf ormance. The best result was seen in the pump with tip clearance of 0.5 mm with a blade thickness of 60% of pitch. These results suggest that a centri fugal pump with thick blades and a small tip clearance can be a promising a lternative as a cardiopulmonary bypass pump.