USA As Represented by Secretary of the Navy

John G Purnell

John G Stricker

Alan J Becnel

Edward Isaac Cohen

A pump-jet type of outboard propulsion unit within a surrounding fluid mem for marine craft or the like, is protectively enclosed within cylindrical shrouding which forms an axial flow passage about the exhaust channel of the propulsion unit through which flow of the fluid medium is induced by rotation of impeller blades. Inflow of the fluid medium to the flow passage is modified at an inlet end of the shrouding by a plurality of angularly spaced vanes attached thereto and extending forwardly therefrom at an angle.

Protective shrouding with debris diverting inflow vanes for pump-jet

The invention features a unique surface configuration which fosters atmosric ventilation and thereby uncomplicatedly reduces drag which is normally associated with implementation of shrouding for a marine impeller. Typical inventive embodiments include a blunt trailing edge and a circumferentially stepped impeller shroud (below the blunt trailing edge), the harmonious union of which affords a generally smooth and unbroken surface which encourages drag-defeating air circulation. During marine navigation, circulation of the air generally describes a path wherein the air first travels linearly downward along the blunt trailing edge, then travels curvingly downward (both clockwise and counterclockwise) along the circumferential step, forming a circumferential air pocket which extends a backward distance increasing in accordance with increasing navigational speed; upon attainment of a threshold navigational speed, the air pocket (virtually) completely surrounds the shroud. According to the invention, many a conventional outboard open propeller assembly can be facilely converted to an inventive outboard shrouded impeller assembly which produces equal or superior performance.

Ventilated outboard motor-mounted pumpjet assembly

The parameters of a rotor bearing assembly are readily changed to facilit evaluation, determination and establishment of optimum bearing clearance and rotor bearing adjustment to minimize noise and vibration, by an arrangement which includes seating of solid deflection pads positioned within a carrier on replaceable adjustment shims and retention of the pads and shims seated in adjusted positions by means of hold-down screws.

Adjustable electric motor bearing system

The invention is directed to a flow energizing system for turbomachinery including means for forming a plurality of rotating jet-sheet blades upstream of an impeller and a component for circumferentially varying the blade geometries of the plurality of rotating jet-sheet blades. The a component for forming a plurality of rotating jet-sheet blades includes: impeller shroud 26 having upstream-projecting axial extension 28 attached coaxially with and projecting upstream of shroud 26; recirculation chamber 30 surrounding shroud and axial extension, 26 and 28; recirculation flow inlet 32 formed by a gap between housing 12 and downstream ends, 20a and 26a, respectively, of impeller 20 and shroud 26, for allowing backflow to pressurize recirculation chamber 30; and a plurality of generally axially-extending jet-sheet slots 34 circumferentially distributed around a periphery of axial extension 28 and passing therethrough. The component for circumferentially varying blade geometries of the plurality of rotating jet-sheet blades includes axially-extending stationary liner 36 disposed concentric with and radially inward of axial extension 28 wherein liner 36 is shaped and configured for selectively covering portions of slots 34.

Flow energizing system for turbomachinery

A water jet propulsion system of improved efficiency with a novel boundary ayer water inlet, and having multiple water jet pumps and motors. The inlet has a large width to height ratio. The pumps may be connected to one drive shaft which can be connected to one or more motors by means of clutches.

Growing community of inventors

Catonsville, MD, United States of America

John G Purnell