Apparatus for propelling fluid, especially for propulsion of a floating vehicle

Abstract

A propeller has a number of blade surfaces or winglets extending helically around its rotational axis in the most streamlined manner. The winglets gradually project at an increasing distance outward with an arcuate shape, each defining a rearwardly concave channel that increases in volume and degree of encirclement rearward on the propeller. In the front of the propeller, the winglets are shaped so that they have edges angled obliquely and diagonally that conformingly and without cavitation cut into the water and cause it to flow smoothly in the channels. In the middle of the propeller, the winglet edges extend rearward so that water entrained in the channel is directed rearward without centrifugal loss. In the rear portion of the propeller, the channels narrow and reduce in volume so as to expel the water from the concavity.

What is claimed is: 
     
         1 . A propeller supported on a floating body so as to be substantially completely submerged in water and rotatable about an axis of rotation to propel the floating body in said water in a forward direction of movement, said propeller comprising:
 a plurality of winglets supported on the floating body for rotation about the axis of rotation;   each of said winglets extending in a generally spiral path about the axis of rotation and having a first surface facing generally rearwardly and a second surface facing generally forwardly;   the first surface of each winglet and the second surface of a respective next adjacent one of the winglets defining therebetween a fluid passage space extending generally spirally around the axis of rotation, said fluid passage space having a varying volume defined as a space radially inward of the winglet;   in a forward portion of the winglet, the volume of the fluid passage space continuously increasing rearwardly, and   in a rearward portion of the winglet, the volume of the fluid passage space reducing continuously rearwardly.   
     
     
         2 . The propeller according to  claim 1 , wherein the winglets are fixedly supported on a longitudinally extending shaft overlying the axis of rotation. 
     
     
         3 . The propeller according to  claim 1 , wherein the first surface extends from a radially inward proximal end portion adjacent the axis of rotation to a radially outward distal end portion spaced rearwardly and radially outward therefrom, and said first surface is concave between the proximal and distal end portions over at least a longitudinal portion of the propeller. 
     
     
         4 . The propeller according to  claim 3 , wherein the first surface extends rearwardly so that in a longitudinal portion between the forward and rearward portions, the first surface radially inwardly encloses at least half of the fluid passage space defined so that water in the fluid passage space is entrained by the first surface against radially outward movement away from the propeller, and the first surface has a cross-section taken along a centerline of the fluid passage space that is substantially a partial circular or oval shape. 
     
     
         5 . The propeller according to  claim 3 , wherein the first surface at the distal end portion thereof extends outwardly and rearwardly at a sloping angle of less than 10 degrees relative to the axis of rotation such that water expelled outwardly of the propeller is caused to flow along the first surface and is directed rearwardly. 
     
     
         6 . The propeller according to  claim 3 , wherein the first surface extends outwardly and rearwardly at an angle of approximately zero degrees relative to the axis of rotation such that water moved radially outwardly of the propeller is caused to flow along the first surface and is re-directed rearwardly. 
     
     
         7 . The propeller according to  claim 3 , wherein the second surface has a proximal end portion adjacent the axis of rotation and a distal end portion rearward and radially outward thereof, said second surface being forwardly convex between the proximal and distal end portions over at least said longitudinal portion of the propeller. 
     
     
         8 . The propeller according to  claim 3 , wherein the first surface of the winglet has a length along said surface, and the length increases from an initial length of zero or near zero at a longitudinally forward end of the winglet to a maximal length at a longitudinally intermediate location of the winglet, and then reduces to a terminal length of zero or near zero at the longitudinally rearward end thereof. 
     
     
         9 . The propeller according to  claim 8 , wherein the first surface is generally flat in cross-section at the longitudinally forward end and is concave over the entire length in the intermediate location. 
     
     
         10 . The propeller according to  claim 8 , wherein the first surface encloses at least 50% of the cross-sectional area of the fluid passage space in the longitudinally intermediate location and rearward thereof, and encloses less than 50% of the volume of the fluid passage space forward thereof, so that the winglet encounters and collects water in the fluid passage space in a forward portion thereof, and entrains and expels water in a rearward portion of the winglet. 
     
     
         11 . The propeller according to  claim 1 , wherein said the plurality of winglets comprises three winglets. 
     
     
         12 . The propeller according to  claim 1 , wherein the fluid passage space extends spirally around the axis of rotation in a spiral path having a pitch, said pitch increasing rearwardly of the winglet. 
     
     
         13 . The propeller according to  claim 1 , wherein the winglets support thereon a generally tubular outer structure surrounding the winglets and supported for rotation therewith, said tubular outer structure having an inward surface defining a passageway and directing flow of water moved by the winglets in a rearward direction through said passageway, said tubular outer structure being generally conical and tapering rearwardly to a rear portion defining a generally circular outlet therein. 
     
     
         14 . A propeller supported on a floating body so as to be completely submerged in water and rotatable about a longitudinal axis of rotation for propelling the floating body in said water, said propeller comprising:
 a shaft rotatably supported on the floating body, said shaft having a forward front end and a rearward back end, and said shaft being driven so as to rotate about the longitudinal axis; and   three propulsion structures supported on and extending in a generally spiral path about said shaft and rotationally staggered with respect to one another;   each of said propulsion structures having a fluid contact surface with a surface width measured along the fluid contact surface from a radially inward end portion to a outward edge portion;   said fluid contact surface having a forward engaging portion, an intermediate fluid entraining portion, and a rearward exhaust portion;   the surface width of the fluid contact surface increasing from the engaging portion to the intermediate fluid entraining portion, and decreasing from the intermediate fluid entraining portion to the exhaust portion;   the fluid contact surface in the intermediate fluid entraining portion being concave and inwardly and rearwardly disposed so as to radially inwardly enclose a spiral fluid flow volume, with said fluid contact surface being shaped such that cross-sections thereof in a plane perpendicular to the longitudinal axis extend curvingly rearward a distance at least as great as a radially outward extension distance of the fluid contact surface.   
     
     
         15 . The invention according to  claim 14 , wherein the spiral path of the propulsion structures increases in pitch from the intermediate entraining portion to the exhaust portion. 
     
     
         16 . The invention according to  claim 14 , wherein the propulsion structures are rotatively staggered by approximately 120 degrees of rotation about the axis of rotation relative to one other. 
     
     
         17 . The invention according to  claim 14 , wherein the surface width of fluid contact surface taperingly increases from the forward engagement portion of the propulsion structure to a maximal surface width in the intermediate entraining portion at a point that is approximately 0.6 to 0.8 L from the forward end of the propulsion structure, where L is an overall longitudinal length of the propulsion structure. 
     
     
         18 . The invention according to  claim 17 , wherein the surface width of fluid contact surface taperingly decreases from said maximal surface width to about zero at the rearward end of the propulsion structure. 
     
     
         19 . The invention according to  claim 14 , wherein said fluid contact surface is shaped such that cross-sections thereof in a plane perpendicular to the longitudinal axis extend curvingly rearward a distance at least 1.5 times as great as the radially outward extension distance of the fluid contact surface. 
     
     
         20 . The invention according to  claim 14 , wherein the cross-section of the propulsion structure in the intermediate portion has a distal outward end, and the fluid entraining surface forms an inward angle to a tangent to a circle about the longitudinal axis of 0 to 5 degrees. 
     
     
         21 . A propeller supported on a floating body in water so as to impel said floating body in a forward direction of movement, said propeller comprising:
 a plurality of winglets supported fixedly with respect to each other so as to rotate together about a longitudinally extending axis of rotation;   each of said winglets comprising   a winglet body portion extending generally spirally about said axis of rotation and having a generally forwardly-disposed forward surface and a generally rearwardly-disposed rearward surface, said forward and rearward surfaces meeting in an acute-angle winglet edge that also extends generally spirally about said axis of rotation;   the rearward surface being concave over at least a longitudinal portion of a longitudinal length of the winglet so as to define a generally rearward facing channel rearward of the winglet body portion such that the rearwardly concave rearward surface has a forwardmost channel surface portion at a forwardmost part of the channel;   the longitudinal portion including a forward intake portion, a retention portion rearward thereof, and an expelling portion rearward of the retention portion;   wherein, in the intake portion, the winglet edge is oriented such that, as the propeller is rotated, the winglet edge passes into the water with a conforming flow from the winglet edge over the forward and rearward surfaces, and a portion of the water flows into the channel, and   wherein, from the intake portion to the retaining portion, the forwardmost channel surface portion of the rearward surface and the winglet edge extend continuously obliquely rearward, the winglet edge extending continuously obliquely rearwardly more steeply relative than the forwardmost channel surface portion, and the rearward surface widens and defines the channel to as to be wider in the retaining portion;   wherein, in the retaining portion, the winglet edge is oriented such that the rearward surface contiguous thereto extends rearward in a direction that differs from the longitudinal direction by no more than the acute angle; and   wherein, in the expelling portion, the channel becomes narrower than in the retention portion.   
     
     
         22 . The propeller according to  claim 21 , wherein the winglets are fixedly attached to a central shaft of the propeller and extend laterally outward therefrom. 
     
     
         23 . The propeller according to  claim 21 , wherein the winglets define a propeller contour that conically tapers outward in the intake portion and narrows radially inward and rearwardly in the expelling portion. 
     
     
         24 . The propeller according to  claim 21 , wherein the forwardmost surface portion extends more steeply rearwardly. 
     
     
         25 . The propeller according to  claim 21 , wherein the winglets are fixedly supported on an interior surface of a tubular propeller structure, and extend radially inward therefrom.