Impeller reduces pressure

Kamewa has introduced a seven-bladed water jet impeller which is said to reduce pressure pulses by an average of 25 per cent, and give a 15 per cent increase in cavitation margin. The additional blade on the impeller means the throughput on each blade is reduced, thereby reducing pressure pulses which in turn lowers noise and vibration.

During the research and development of the new impeller, Kamewa found that the boundary layer around the hull was much thicker than previously thought. This leads to lower pressure at the intake for the jets and so the lower pressures achieved by the seven-bladed impeller is even more vital in combating cavitation, says the company.

Improved cavitation characteristics allow the possibility of selecting a smaller jet size for a given output, says the company.