High mass and low pressure liquid propulsion with counter-rotating impellers with reversal of drive to impellers to reverse flow direction

摘要

A high mass/low flow pressure propulsion device, typically for jet boat reversing, has two counter-rotating impellers 14,15 located in a housing with water normally flowing via housing inlet 12 to housing outlet 19. The rotational drive direction for the impellers is reversed to cause water to flow from outlet to inlet. An anti-ventilation hood 35 is provided to prevent air being sucked into the outlet, and is necessary unless the outlet is fully submerged.