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US 5,634,831 AGranted
Water jet propulsion unit for use in a jet boat
OwnerRichard G. Davies, Barry J. Daviesinventors
Life of this patent
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Abstract
A water jet propulsion unit intended for use in jet boats. The unit has an intake section, a pump section and a nozzle section. In the pump section there are two counter-rotating impellers on concentric counter-rotating shafts calibrated so that any radial flow created in the upstream impeller is converted into axial flow by the downstream impeller. In one embodiment the nozzle section has a throttled outlet to allow for a high mass/low pressure operation while maintaining pump priming. There are no support structures or stators downstream of the intake section in the preferred embodiment.
Claims17
A water jet propulsion unit comprising:
- an intake section;
- a pump section;
- and
- a nozzle section;
- the sections being in smooth communication with one another;
- a single pair of counter-rotating impellers in said pump section, the downstream impeller being configured and calibrated to convert any radial flow created by the upstream impeller into axial flow, said counter-rotating impellers being each mounted on separate counter-rotating drive shafts, said drive shafts extending forwardly from said pump section through said intake section;
- drive receiving means outside said intake portion on said drive shafts;
- mounting means upstream of said counter-rotating impellers comprising one or more hydro-dynamic vanes, said counter-rotating shafts being bearingly mounted in said mounting means;
- there being no stators downstream of said intake section;
- and
- said nozzle portion having an outlet of cross-sectional area from about 0.55 to less than the swept area of the forward of said impellers so that the unit is operated in a high mass/low pressure mode.
8 more elements
Dependencies are inferred from the claim text.