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US 6,422,904 B1Granted
Water jet propulsion unit for use in water borne craft
OwnerRichard Gwyn Davies, Barry John Daviesinventors
Life of this patent
Estimating the term…
Abstract
A water jet propulsion unit for water borne craft including two contra rotating impellers, located in an upstream pump housing and a downstream pump housing respectively, and mounted on coaxial shafts. A pressure control priming device in the form of a spring loaded collapsible skirt is located between the impellers. The pressure in the downstream pump housing can be maintained at atmospheric pressure by the controlled admission of air through air inlets.
Claims7
A water jet propulsion unit comprising:
- an intake section;
- a pump section which includes a pump housing enclosing an upstream axial flow impeller followed immediately downstream by a pressure control priming device;
- followed by a second pump housing containing a further downstream impeller of opposite pitch;
- said downstream pump housing having an air entry control system;
- said air entry control system including a sliding ring being hydraulically operated so that the quantity of air entering the downstream pump housing can be controlled precisely;
- said air being permitted to enter the downstream pump housing via ports cast into the downstream pump housing;
- said impellers being separately mounted on contra rotating shafts;
- said coaxially arranged shafts being located at the outlet end of the downstream pump housing by a bearinged three or four vane support;
- said impellers being able to individually rotate at peripheral speeds above 30 meter per second;
- said downstream impeller being permitted to operate at atmospheric pressure whilst in operating mode;
- said intake housing, upstream and downstream pump housings, all being in smooth communication with each other;
- said water jet propulsion unit being able to be configured to operate in a pressure range above or below 276 kPA.
9 more elements
A water jet propulsion unit comprising:
- an intake section;
- a pump section which includes a pump housing enclosing an upstream impeller followed immediately downstream by a pressure control priming device;
- followed by a second pump housing containing a further downstream impeller of opposite pitch;
- said downstream pump housing having an air entry control system;
- said air entry control system including a sliding ring being hydraulically operated so that the quantity of air entering the downstream pump housing can be controlled precisely;
- said air being permitted to enter the downstream pump housing via ports cast into the downstream pump housing;
- said impellers being separately mounted on contra rotating shafts;
- said downstream impeller being permitted to operate at atmospheric pressure whilst in operating mode;
- said intake housing, upstream and downstream pump housings;
- all being in smooth communication with each other.
7 more elements
Dependencies are inferred from the claim text.