US3465523A - Hydraulic power unit - Google Patents

Description

p 9, 1969 J. J. CLARK, JR

HYDRAULIC POWER UNIT 5 Sheets-Sheet 1 Filed Sept. 11, 1967 FIG. 3.

a fl p 9, 1969 J. J. CLARK, JR

HYDRAULIC POWER UNIT 5 Sheets-Sheet. 2

Filed Sept. 11, 1967 Sept. 9, 1969 J. J. CLARK, JR 3,465,523

HYDRAULIC POWER UNIT Filed Sept. 11, 1967 5 Sheets-Sheet 5 FIG/Z.

United States Patent 3,465,523 HYDRAULIC POWER UNIT John J. Clark, Jr., Rte. 2, Box 313, Pacific, Mo. 63069 Filed Sept. 11, 1967, Ser. No. 666,799 Int. Cl. B6311 11/00; F04d 13/12, 13/02 US. Cl. 72-96 14 Claims ABSTRACT OF THE DISCLOSURE The housing of a hydraulic power unit has a liquid-sealing pumping chamber and a pressure-generating chamber; and the multi-blade impeller of that hydraulic power unit extends into and is disposed within both of those chambers. That liquid-sealing pumping chamber has a surface which inclines toward and communicates with that pressure-generating chamber; and the portions of the blades of that impeller which are disposed within that liquidsealing pumping chamber will coact with that surface to apply directional forces, to the liquid immediately adjacent that surface, which are large enough to keep the liquid in that pressure-generating chamber from leaking into and through that liquid-sealing pumping chamber. The impeller has a separator of annular form extending upwardly from the upper portions of the blades of that impeller; and that separator defines an inner annular area and an outer annular area for those impeller blades.

provide a hydraulic power unit which includes a multiblade impeller that draws liquid into a housing and that expels that liquid through the discharge opening of the pressure-generating chamber of that housing.

Where a hydraulic power unit must develop large hydraulic pressures, it is customary to provide high-pressure mechanical seals between the impeller and the housing of that hydraulic power unit to keep the pressurized liquid in the pressure-generating chamber of that hydraulic power unit from leaking between that impeller and that housing. However, the use of such mechanical seals is objectionable because such seals increase the frictional forces between the impeller and the housing of the hydraulic power unit, and thereby dissipate appreciable portions of the power supplied to the impeller. In addition, the use of high-pressure mechanical seals is objectionable because such seals tend to wear, and thus tend to increase the problems of maintaining and servicing the hydraulic power units. Consequently, it would be desirable to provide a hydraulic power unit which could develop large hydraulic pressures but which did not require high-pressure mechanical seals between the impeller and housing thereof. The present invention provides such a hydraulic power unit; and it does so by causing the impeller and the housing thereof to interact to develop a hydraulic seal which will keep pressurized liquid from leaking between that impellerand that housing. It is, therefore, an object of the present invention to provide a hydraulic power unit wherein the impeller and housing coact to develop a hydraulic seal which will keep pressurized liquid from leaking between that impeller and that housing.

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The hydraulic power unit provided by the present invention has a liquid-sealing chamber and a pressure-generating chamber in the housing thereof; and a multi-blade impeller of that hydraulic power unit extends into and is disposed within both of those chambers. That liquidsealing chamber has a surface which inclines toward and communicates with that pressure-generating chamber; and the portions of the blades of that impeller which are disposed within that liquid-sealing chamber will coact with that surface to apply directional forces, to the liquid immediately adjacent that surface, which are large enough to keep the liquid in that pressure-generating chamber from leaking into and through that liquid-sealing chamber. The resulting hydraulic seal will enable that hydraulic power unit to develop large hydraulic pressures, without any need of high-pressure mechanical seals between the impeller and housing thereof. It is, therefore, an object of the present invention to provide a hydraulic power unit which has a liquid-sealing chamber and a pressure-generating chamber in the housing thereof; and which has a surface in the liquid-sealing chamber thereof that coacts with the impeller thereof to apply directional forces, to the liquid immediately adjacent that surface, which are large enough to keep the liquid in that pressure-generating chamber from leaking into and through that liquid-sealing chamber.

Hydraulic power units can be used to propel boats; but it has been found that when the impellers of those hydraulic power units are rotated at high speeds, cavitation occurs in the water immediately above those impellers. The resulting flow of air to those impellers reduces the efliciencies of those hydraulic power units, and it can permit the internal combustion engines which drive those hydraulic power units to speed up to hurtful values of speed. Consequently, it would be desirable to provide a hydraulic power unit which could be operated at high speeds without causing cavitation to occur in the water immediately about the impeller thereof. The present invention provides such a hydraulic power unit; and it is, therefore, an object of the present invention to provide a hydraulic power unit which can be operated at high speeds without causing cavitation to occur in the water immediately above the impeller thereof.

The hydraulic power unit provided by the present invention prevents cavitation in the water immediately above the impeller thereof by using a multi-blade impeller which has an annular separator extending upwardly from the upper edges of the blades thereof to define an inner annular; area and an outer annular area for that impeller. In addition, that hydraulic power unit prevents cavitation in the water immediately above the impeller thereof by forming and spacing those portions of the impeller blades which are within the inner annular area and which are below the level of the separator so they define liquid passages which are larger than the liquid passages defined by those portions of the impeller blades which are within the inner annular area but are above the level of the lower edge of that separator. The overall result is that sufficient liquid will pass to and flow through the inner annular area of the impeller to prevent cavitation in the water immediately above that impeller. It is, therefore, an object of the present invention to provide a hydraulic power unit with a multi-blade impeller which has an annular separator extending upwardly from the upper edges of the blades thereof to define an inner annular area and an outer annular area for that impeller, and which has liquid passages in the lower portion of that inner annular area that are larger than the liquid passages in the upper portion of that inner annular area.

Other and further objects and advantages of the present invention should become apparent from an examination of the drawing and accompanying description.

In the drawing and accompanying description two preferred embodiments of the present invention are shown and described but it is to be understood that the drawing and accompanying description are for the purpose of illustration only and do not limit the invention and that invention will be defined by the appended claims.

In the drawing:

FIG. 1 is a side elevational view of an outboard motor in which one preferred embodiment of hydraulic power unit provided by the present invention is incorporated,

FIG. 2 is a sectional view, on a larger scale, through the outboard motor of FIG. 1, and it is taken along the plane indicated by the line 2--2 in FIG. 1.

FIG. 3 is a sectional view, on a still larger scale, through the outboard motor of FIG. 1, and it is taken along the plane indicated by the line 3-3 in FIG. 2,

FIG. 4 is a sectional view, on the scale of FIG. 3, through the outboard motor of FIG. 1, and it is taken along the plane indicated by the line 4-4 in FIG. 3,

FIG. 5 is a further sectional view, on the scale of FIG. 3, through the outboard motor of FIG. 1, and it is taken along the plane indicated by the line 55 in FIG. 3,

FIG. 6 is a plan view, on the scale of FIG. 3, of the impeller of the hydraulic power unit incorporated in the outboard motor of FIG. 1.

FIG. 7 is a sectional view through the impeller of FIG. 6, and it is taken along the plane indicated by the line 7-7 in FIG. 6,

FIG. 8 is a sectional view, on the scale of FIG. 7, through the impeller of FIG. 6, and it is taken along the plane indicated by the line 88 in FIG. 7.

FIG. 9 is a further sectional view, on the scale of FIG. 7, through the impeller of FIG. 6, and it is taken along the plane indicated by the line 9-9 in FIG. 6,

FIG. 10 is a still further sectional view, on the scale of FIG. 7, through the impeller of FIG. 6, and it is taken along the plane indicated by the line 10-10 in FIG. 6,

FIG. 11 is yet another sectonal view, on the scale of FIG. 7, through the impeller of FIG. '6, and it is taken along the plane indicated by the line 11--11 in FIG. 6,

FIG. 12 is a vertical section through a second embodiment of hydraulic power unit that is provided by the present invention and that is used as an hydraulic pump, and

FIG. 13 is a sectional view through the hydraulic power unit of FIG. 12, and it is taken along the plane indicated by the line 1313 in FIG. 12.

Referring to the drawing in detail, the numeral generally denotes an outboard motor in which one of the hydraulic power units of the present invention is incorporated. That outboard motor has a standard and usual internal combustion engine, has standard and usual controls for that internal combustion engine, has a standard and usual clamp which can secure it to the transom of a boat, and has a standard and usual housing 21 which extends down into the water and which encases the shaft of that outboard motor. The housing 21 also encases the tube which supplies cooling water to the internal combustion engine of the outboard motor 20; and it serves as a passage through which the spent cooling water and products of combustion are released.

The hydraulic power unit that is incorporated into the outboard motor 20 has a housing which is generally denoted by the numeral 22; and the upper surface of that housing is formed so it can confront and abut the lower surface of the housing 21 of that outboard motor. Screws will normally secure that housing to the housing 21 of that outboard motor. The upper portion of the housing 22 has a generally cylindrical passage 24 for the lower end of the shaft 26 of the outboard motor. A mount 36 is disposed within an annular recess 27 adjacent the upper end of the passage 24; and the outer race of an anti-friction bearing 28 is disposed within an annular recess in the under surface of that mount. The outer race of antifriction bearing 30 is disposed within an annular recess 29 adjacent the lower end of that passage. The anti-friction bearings 28 and 30 will hold the lower end of the shaft 26 so it is concentric with the passage 24. A sleevelike spacer 32 surrounds the portion of the shaft 26 which is immediately below the anti-friction bearing 30; and it will abut the lower face of the inner race of that antifriction bearing. A tubular spacer 34 surrounds the portion of that shaft which is located between the inner races of the anti-friction bearings 28 and 30; and that tubular spacer abuts the confronting faces of those inner races. The upper surface of the inner race of the anti-friction bearing 28 will abut a shoulder at the lower face of a larger-diameter portion 37 of the shaft 26. A grease retainer 38 is held within an annular recess in the upper surface of the mount 36; and that grease retainer will encircle and engage the larger diameter portion 37 of the shaft 26. A grease retainer 40 encircles and engages the upper portion of the spacer 32, and also engages the lower end of the passage 24.

The numeral 42 denotes a frusto-conical surface which defines a frusto-conical liquid-sealing chamber within the central portion of the housing 22; and the numeral 44 denotes a pressure-generating chamber in the bottom portion of that housing. That pressure-generating chamber has concave walls, as shown particularly by FIGS. 3 and 4; and the forward wall of that pressure-generating chamber is semi-circular in plan view and is about one hundred and eighty degrees in angular extent while the side walls of that pressure-generating chamber are straight in plan view and are tangential to the rear portions of that forward wall. The frusto-conical surface 42 extends downwardly and outwardly and merges into the pressure-generating chamber 44. A generally-rectangular outlet 46 is provided for the pressure-generating chamber 44; and that generally-rectangular outlet is disposed adjacent the rear of the housing 22 for the hydraulic power unit. A generally-circular opening 45 is provided in the bottom of the pressure-generating chamber 44; and a generally circular closure 47 is provided for that opening. The edges of that generally-circular opening and of that generally circular closure are formed to provide a rabbet joint; and that rabbet joint will enable the opening-defining portions of the housing 22 to underlie the outer edges of the generally-circular closure 47 and thereby provide a positive and direct support for that generally circular closure. A baffle 49 is provided in the upper portion of the pressuregenerating chamber 44; and that baflle extends toward but stops short of the impeller 60 of the hydraulic unit. That bafile is displaced about forty-five degrees from the longitudinal centerline of the housing 22; and the forward face of that bafiie extends outwardly and then forwardly to the port side wall of the pressure-generating chamber 44 to define a pocket 51.

The numeral 48 denotes a passage which has the lower end thereof openingto and communicating with the upper portion of the pressure-generating chamber 44, as indicated particularly by FIG. 4. The upper end of that passage extends to and communicates with a vertically-directed tube 50 which extends upwardly through the housing 21 of the outboard motor 20 to supply cooling water to the internal combustion engine of that outboard motor. A large cross-section passage 52 is formed in the housing 22; and the upper end of that passage communicates with the passage in the housing 21 of the outboard motor which guides the spent cooling water and products of combustion downwardly toward the housing 22. The passage 52 terminates in an outlet 54 which is located adjacent the rear of the housing 22 and which is disposed above the level of the generally-rectangular outlet 46.

The housing 22 has a large inlet chamber 55 which surrounds, and which extends upwardly above the level of, that portion of that housing which defines the liquid-sealing chamber and the pressure-generating chamber 44. Water can freely enter that inlet chamber through openings in the gratings 56 which define the major portions of the walls of that inlet chamber; and those gratings can be made integral with the housing 22 or can be made as removable walls for that housing. A liquid-guiding surface 58 curves downwardly and inwardly from the upper portion of the interior of the inlet chamber 55; and that liquidguiding surface is smoothly rounded as indicated particularly by FIGS. 3 and 4. The front of the housing 22 is generally triangular in plan; and that generally-triangular front is important, because it minimizes the tendency of leaves, moss, weeds and other foreign matter to close and block the openings in the gratings 56.

The impeller 60 of the hydraulic power unit shown in FIGS. 111 has a hub 61 which accommodates the lower end of the shaft 26, has a shroud 63 at the bottom thereof, and has ten blades 62 which are integral with that hub and with that shroud. The lower end of the shaft 26 has a thread thereon; and that thread will mate with an internal thread in the hub 61. The upper end of the hub 61 abuts the lower end of the sleeve-like spacer 32; and tightening of the internal thread in that hub relative to the thread on the lower end of the shaft 26 will clamp the inner race of the anti-friction bearing 28 against the shoulder at the lower face of the larger-diameter portion 37 of that shaft, will clamp the tubular spacer 34 against the lower face of that inner race, will clamp the inner race of the anti-friction bearing 30 against the lower face of that tubular spacer, 'will clamp the sleeve-like spacer 32 against the lower face of the latter anti-friction bearing, and will clamp the impeller 60 against the lower face of that sleeve like spacer. As a result, the shaft 26, the inner races of the anti-friction bearings 28 and 30, the tubular spacer 34, the sleeve-like spacer 32, and the impeller 60 will rotate as a unit. The engine of the outboard motor 20 will rotate the impeller 60 in the clockwise direction in FIGS. 5, 6, 8 and 13, as indicated by directional arrows.

Each of the blades 62 of the impeller 60 has the outer end thereof inclined to the axis of the hub 61, as shown particularly by FIGS. 3, and 11; and the angle between the shroud 63 and the leading face of the outer end of any of those impeller blades should not exceed forty-five degrees. The outer end of each of the impeller blades 62 has a lower portion 65 which is machined to define a small part of the surface of a theoretical cylinder that is concentric with the hub 61; and the outer end of each of those blades has an upper portion 64 which is machined to define a small part of the surface of a theoretical cone that is concentric with that hub. The upper portions 64 of the impeller blades 62 are disposed Within the frustoconical liquid-sealing chamber of the housing 22, as shown particularly by FIG. 3; and the angle of generation of the theoretical cone defined by those upper portions will be equal to the angle of generation of the frusto-conical surface 42 of that liquid-sealing chamber. However, the upper portions 64 will be spaced inwardly of that frusto-conical surface so the impeller blades 62 will not rub against that frusto-conical surface. The lower portions 65 of the impeller blades 62 are disposed within the upper portion of the pressure-generating chamber 44, as shown particularly by FIG. 3.

An annular separator 66 is secured to, and is rotatable with, the impeller 60; and that separator is located intermediate the inner ends and the outer ends of the upper edges of those impeller blades, as shown particularly by FIGS. 4 and 6, to define an inner annular area and an outer annular area for that impeller. That separator is convexo-concavo in configuration, as shown particularly by FIG. 7; and the portion thereof which extends downwardly below the upper edges of the impeller blades 62 is generally cylindrical, whereas the portion thereof which extends upwardly above those upper edges bows outwardly to provide a bell-shaped inlet. The upper portion of the annular separator 66 coacts with the liquid-guiding surface 58 at the interior of the housing 22 to define an annular passage through which liquid can flow smoothly and with minimal turbulence to reach the inner annular area of the impeller 60. That upper portion of that annular separator coacts with the upper edge of the portion of the housing 22 which defines the liquid-sealing chamber to define an annular passage through which liquid can flow smoothly and with minimal turbulence to reach the outer annular area of the impeller 60.

The leading face of each of the impeller blades 62 is a compound surface; and, similarly, the trailing face of each of those blades is a compound surface. For example, the upper part 59 of the leading face, of the portion of each impeller blade 62 which is within the inner annular area of the impeller 60, is substantially plane and is inclined to the axis of the hub 61, as shown particularly by FIG. 7; and the lower part 69 of the leading face of that portion is substantially plane and is both axially-directed and radially-directed and the part between those two substantially-plane parts is concave and smoothly merges into those two substantially-plane parts. The upper part 75 of the leading face, of the portion of each impeller blade 62 which is disposed outwardly of but which is immediately adjacent the separator 66, is substantially plane and is inclined to the axis of the hub 61 and is essentially a continuation of the upper part 59. The lower part 77 of the leading face, of the portion of each impeller blade 62 which is disposed outwardly of but which is immediately adjacent the separator 66, is substantially plane and is both axially-directed and radially-directed and is essentially a continuation of the lower part 69; and the part between the upper part 75 and the lower part 77 is concave and smoothly merges into those two parts. The upper part 67 of the leading face, of the portion of each impeller blade 62 which is at the outer end of that impeller blade, as shown particularly by FIGS. 7 and 9, is substantially plane, is inclined to the axis of the hub 61, and also is inclined to the substantially-plane upper part 75. That part defines a plane which is parallel to, but which is disposed forwardly of, the plane that is defined by the upper part 75 of the leading face of the next-succeeding impeller blade. The part of the leading face of the portion of each impeller blade 62 which is intermediate the part 67 and the part 75 is convex and smoothly merges into those two parts. The lower part 71 of the leading face, of the portion of each impeller blade 62 which is at the outer end of that impeller blade, is convex and is axially-directed. The part of the leading face of each impeller blade "which is between the parts 67 and 71 is concave and smoothly merges into those two parts. The parts 67 of the leading faces of the various impeller blades 62 should always coact with the frusto-conical surface 42 to subtend obtuse angles.

The upper part of the trailing face of each of the various impeller blades 62 is generally parallel to the upper part of the leading face of that impeller blade, as indicated by FIGS. 3 and 7 and 9-11. Also, the inner portion of the lower part of the trailing face of each of the various impeller blades 62 is generally parallel to the inner portion of the lower part of the leading face of that impeller blade, as indicated by FIGS. 10 and 11. However, the outer portion of the lower part of the trailing face of each of the various impeller blades 62 is essentially plane and coacts with the shroud 63 to subtend an obtuse angle, as shown particularly by FIG. 3; and that portion is denoted by the numeral 73. The portions 73 coact with the contiguous axially-directed and radially-directed inner portions of the lower parts of the trailing faces of the impeller blades 62 to define pockets at those trailing faces.

The tops of the impeller blades 62 are tapered to a fine edge, but those tops quickly and smoothly widen into the normal thicknesses of those impeller blades. Those thicknesses are substantially uniform, except where the portions 73 diverge from the parts 71 to provide increased thicknesses for the outer ends of the lower parts of the impeller blades. While the leading faces and the trailing faces of the impeller blades 62 are compound surfaces, the various portions and parts of those trailing and leading faces merge smoothly into each other, so those leading and trailing faces will not develop appreciable turbulence and eddying.

It will be noted that the upper parts of the portions of the impeller blades 62 which are within the inner annular area of the impeller 60 are inclined to the axis of the hub 61, whereas the lower parts of those portions of those impeller blades are axially-directed. This is important; because it makes the spaces between, and hence the liquid passages defined by, those lower parts larger than the spaces between, and the liquid passages defined by, those upper parts. As a result, liquid can tend to flow outwardly from the spaces between those lower parts with less resistance and at higher rates than liquid can enter and pass through the spaces between those upper parts; and the resulting reduced pressures in the spaces between those lower parts will foster and enhance the flow of liquid into and through the inner annular area of the impeller 60.

In the operation of the hydraulic power unit shown by FIGS. 1-11, the entire impeller 60 will be immersed in water which will enter the inlet chamber 55 through the openings in the porous gratings 56. Those openings are large enough and are sufliciently numerous to make certain that the impeller 60 will receive all of the liquid that it can move. The shaft 26 will rotate that impeller in the clockwise direction in FIGS. 5, 6 and 8; and this means that the impeller blades 62 will be moving from right to left in FIG. 3 and will be moving from left to right in FIGS. 10 and 11. The rotation of that impeller will apply both a downward and an outward thrust to the waterthe downward thrust being provided primarily by the upper parts 59 and 75 of the leading faces of the impeller blades, and the outward thrust being provided by centrifugal action, by the parts 67, and by the portions 71. The water in the spaces between the intermediate areas and the inner ends of the impeller blades 62 will respond to the downward thrust thereon to move downwardly toward the shroud 63 of the impeller 60, and then will move outwardly into the pressure-generating chamber 44; and the water in the spaces between the outer ends of the portions 64 of those impeller blades will respond to the outward thrust thereon to move toward the frusto-conical surface 42 of the liquid-sealing chamber and will respond to the downward thrust thereon to move toward that pressure-generating chamber.

The pressure which the impeller 60 develops within the pressure-generating chamber 44 can be quite high; and that pressure will cause water to flow to and through the generally-rectangular outlet 46. The water which confronts that generally-rectangular outlet as it is discharged from the impeller 60 will pass directly to and through that generally-rectangular outlet, but the water which does not confront that generally-rectangular outlet as is discharged from he impeller 60 will either pass through the concave, peripheral portion of the pressure-generating chamber 44 to that generally-rectangular outlet or will pass downwardly and along the bottom surface of the shroud 63 of that impeller to that generally-rectangular outlet. In either event, the water will have a large, substantially unobstructed path through which it can flow as it passes to the generally-rectangular outlet 46.

The baffle 49, which extends toward but stops short of the outer ends of the blades 62 of the impeller 60, will keep the water adjacent that impeller from moving uninterruptedly through an annular path immediately adjacent the outer ends of the impeller blades 62. The pocket 51 which is disposed forwardly of the forward face of that bafile will facilitate prompt outward flow of liquid from the spaces between the lower portions 65 of the impeller blades 62, after those portions have moved forwardly past that battle, and thus will foster and enhance discharging of liquid from the impeller 60 into the pressure-generating chamber 44. As a result, the bulk of the water that is forced downwardly into the pressure-generating chamber 44 by the impeller 60 will promptly move to and through the generally-rectangular outlet 46. A small part of that water will enter the passage 48, and will be guided to the tube 50; and that part of that water will then be directed to the cooling jacket of the internal combustion engine. The spent cooling water from that cooling jacket will then be discharged into the passage, for spent cooling water and the products of combustion, within the housing 21 of the outboard motor 20; and it will then move downwardly into and through the passage 52 and out through the outlet 54.

Because the water in the pressure-generating chamber 44 is intended to, and does, flow to and through the generally-rectangular outlet 46, the pressure within that chamber will be less than the pressure within the liquidsealing chamber. As a result, the pressure within that liquid-sealing chamber will tend to cause some of the water in that chamber to move downwardly toward and into the pressure-generating chamber 44. The inclination of the frusto-conical surface 42 will cause the water, which flows outwardly beyond the outer ends of the upper portions 64 of the impeller blades 62 and strikes that frusto-conical surface, to be directed downwardly toward the pressure-generating chamber 44; and the outward and downward thrust which the parts 67 of the outer portions of those impeller blades apply to the water in the liquid-sealing chamber also will tend to direct that water downwardly toward that pressure-generating chamber. The downward forces applied to the water in the liquid-sealing chamber will coact with the difference between the pressures in the liquid-sealing and pressuregenerating chambers to force water to move downwardly from the liquid-sealing chamber into the pressure-generating chamber; and that water will effectively keep water in the latter chamber from leaking upwardly between the frusto-conical surface 42 and the outer ends of the impeller blades 60. The overall result is that the hydraulic power unit of FIGS. 1-11 can effectively prevent leakage of water from the pressure-generating chamber through the liquid-sealing chamber-despite the complete and total absence of high pressure mechanical seals for that pressure-generating chamber. This means that the hydraulic power unit provided by the present invention will have minimal frictional resistance and will avoid the maintenance problems inherent in the use of high pressure mechanical seals for the pressure-generating chamber of a hydraulic power unit.

The water that is discharged through the generallyrectangular outlet 46 will act upon the water adjacent that generally-rectangular outlet to provide direct-actiontype propulsive forces. Also, as that water flows outwardly through that generally-rectangular outlet, it will enable the hydraulic power unit to provide reaction-type propulsive forces. The combination of those direct-action-type and reaction-type propulsive forces will enable the hydraulic power unit to deliver the power of the internal combustion engine efficiently and effectively; and the boat on which the outboard motor 20 is mounted will respond to those propulsive forces to start moving through the water. As that boat so moves, the housing 22 may encounter weeds, moss, leaves and other foreign matter; but the acute angle subtended by the forward portions of the sides of the housing 22 will cause virtually all of the weeds, moss, leaves and other foreign matter to pass by rather than lodge on that housing. This means that the hydraulic power unit of FIGS. 1l1 can be operated efiiciently and effectively in areas where other hydraulic power units would quickly become fouled. It will be noted that the housing 22 completely encloses the impeller 60; and hence that impeller cannot harm, and cannot be harmed by, persons or objects contacting that housing.

The water which enters the inlet chamber 55 during the operation of the hydraulic power unit of FIGS. 1-11 will be drawn downwardly into the spaces between the impeller blades 62. Part of that water will pass between the outer surface of the annular separator 66 and the upper edge of the portion of the housing 22 which defines the frusto-conical surface 42; and that portion of the Water will be drawn down into the spaces between the outer ends of the impeller blades 62. Other of the water in the inlet chamber 55 will pass between the inner surface of the annular separator 66 and the water guiding surface 58 of the housing 22; and that portion of the water will be drawn downwardly into the spaces between the inner ends of the impeller blades 62. As pointed out hereinbefore, the spaces between the axially-directed lower parts of the inner ends of the impeller blades 62 are larger than the spaces between the inclined upper parts of those inner ends; and, similarly, the spaces between the axially-directed lower parts of the outer ends of those impeller blades are larger than the spaces between the inclined upper parts of those outer ends. The resulting, relatively-large liquid passages defined by those lower parts foster and enhance the movement of water into and downwardly through the inner and outer annular areas of the impeller 60. The resulting smooth and full flow of water to and through those annular areas of that impeller will prevent cavitation in the water above that impeller.

In one preferred embodiment of the hydraulic power unit shown in FIGS. 1-11, the outboard motor was powered by an internal combustion engine which had a rating of three and one-half horsepower at four thousand revolutions per minute, the diameter of the shroud 63 of the impeller 60 was three inches, the axial distance from the top of each impeller blade 62 to the upper surface of that shroud was approximately three-quarters of an inch, the bottom of the annular separator 66 extended down below the level of the upper edges of the impeller blades 62 about one-eighth of an inch, and the upper edge of that annular separator extended above the upper edges of those impeller blades about three-eighths of an inch. The lower one-third of each of the impeller blades, or about one-quarter of an inch, was dis osed within the pressure-generating chamber 44; and the upper twothirds of the height of each of those impeller blades, or about one-half of an inch, were disposed in the liquidsealing chamber. The upper portion of the outer surface of the annular separator 66 was an are which had the upper edge of the frusto-conical surface 42 as its geometric center; and hence all radial distances from that upper edge to that upper portion were equal-thereby assuring a full and unimpeded flow of water to the outer portions of the impeller blades '62. The distance between the outer ends of the upper portions 64 of the impeller blades 62 and the frusto-conical surface 42 of the housing 22 was about three thousandths of an inch. The generally-rectangular outlet 46 was one-half of an inch high and was about three and five-eighths of an inch wide. The internal combustion engine of the outboard motor 20 rotated the impeller 60 at speeds up to four thousand revolutions per minute and no cavitation occurred in the water above that impeller or in the water adjacent the housing 22. When the impeller 60 was operated without the annular separator 66, cavitation occurred in the water above that impeller at speeds of about thirty-four hundred revolutions per minute. Many standard and usual hydraulic power units would cause cavitation to occur in the water above them if they were operated at speeds as low as twenty-five hundred revolutions per minute. The internal combustion engine, of the outboard motor 20 to which the housing 22 was secured, had a top speed of about four thousand revolutions per minute; and it was the limitation of the speed of that engine rather than the ability of the impeller 60 to prevent cavitation which fixed the upper speed limit of the test of the anti-cavitation capabilities of the impeller 60.

The effectiveness of the water seal developed in the liquid-sealing chamber is particularly noteworthy when very heavy liquid pressures are developed in the pressuregenerating chamber 44. To illustrate that effectiveness, the size of the generally-rectangular outlet 46 was progressively reduced to increase the hydraulic pressure within the pressure-generating chamber; and that size was reduced until the pressure in that chamber increased to the point where it reduced the speed of the internal combustion enginealthough that engine was being operated at full power and had a three and one-half horsepower rating. Specifically, the size of the generally-rectangular outlet 46 was reduced progressively until the speed of the internal combustion engine decreased from about four thousand revolutions per minute to about twenty-five hundred revolutions per minute; and that reduction in speed could not have occurred unless the liquid-sealing chamber was effectively minimizing or preventing leakage of water from the pressure-generating chamber to and through that liquid-sealing chamber.

The upper parts of the impeller blades 62 perform four functions, namely, they apply centrifugal forces to the water in the spaces between them, they force water downwardly into the spaces between the lower parts of those blades, they apply downward and outward thrusts to the water adjacent the periphery of the impeller 60, and they draw water downwardly into the spaces between them. The lower parts of those impeller blades 62 perform two functions, namely, they force water to move outwardly into the pressure-generating chamber 44, and they draw water downwardly from the spaces between the upper parts of those impeller blades. The overall result is that the impeller blades 62 smoothly and effectively cause relatively-large volumes of water to flow into and through the spaces in the inner annular area, as well as into and through the spaces in the outer annular area, of the impeller -60thereby avoiding cavitation in the water above that impeller, and also providing sufficient flow of water to develop substantial pressures within the pressure-generating chamber 44.

The angular displacement of the parts '67 from the parts of the impeller blades '62 enables the former parts to perform four functions: namely, they stiffen the outer ends of those impeller blades, they apply outward and downward thrusts to the Water in the liquid-sealing chamber, they create reduced pressures behind the trailing faces of those impeller blades, and they provide ample discharge areas between them and the parts 73 of the preceding impeller blades. As a result, the impeller blades 62 are able to rotate at high speed, to apply heavy pressures to the water in the liquid-sealing chamber, and to draw ample quantities of water into and to discharge corresponding quantities of water from the spaces between them without flexing or vibrating.

It will be noted that the leading edge of each impeller blade 62 overlaps the trailing edge of the immediatelypreceding impeller blade, and that each impeller blade 62 has a length which is greater than the spacing between adjacent impeller blades. As a result, those impeller blades define elongated, open-sided liquid passages that contain pressurized volumes of liquid which overlap circumferentially to provide a substantially-continuous annulus of pressurized liquid. That substantially-continuous annulus of pressurized liquid will provide the desired liquid seal for the liquid in the pressure-generating chamber.

The hydraulic power unit of FIGS. 1-11 is shown as it appears when it is incorporated into an outboard motor. That hydraulic power unit will be equally as useful and elfective when it is incorporated into an inboard motor propulsion system.

FIGS. 12 and 13 show a hydraulic power unit in the form of a high volume, high pressure liquid pump. That liquid pump is generally denoted by the numeral and it includes a housing which has an upper section 92 and a lower section 94. An internally-threaded connector 96 on the upper section 92 serves as the inlet opening for that liquid pump; and that connector communicates with an inlet chamber 98 which performs the same functions that are performed by the inlet chamber 55 of the housing 22 of the hydraulic power unit of FIGS. 111. The lower section 94 has an internally-threaded connector 100; and that connector serves as the discharge opening of the liquid pump 90. A gasket 102 is disposed between the confronting faces of the upper and lower sections 92 and 94, respectively, of the pump housing. The liquid pump 90 includes an impeller 60 which can be identical to the similarly-numbered impeller in the hydraulic power unit of FIGS. l-ll; and the upper portions of the blades of that impeller will be disposed within the frusto-con1cal liquid-sealing chamber of that liquid pump, and the lower portions of those blades will be disposed within the pressure-generating chamber 44 of that liquid pump. The function and operation of the impeller 60 will be the same as the function and operation of the similarly-numbered impeller in the hydraulic power unit of FIGS. l-ll. Where the liquid pump 90 is made from appropriate materials, it can be used to pump corrosive, highly-heated, and other hard-to-pump liquids.

The lower section 94 of the pump housing is secured to the upper section 92 of that pump housing by screws 99 which are spaced apart equal angular distances. As a result, that lower section can be set at different angles relative to that upper section to provide a desirable angular relation between the connectors 96 and 100.

If desired, a number of impellers 60 could be mounted on the same shaft to form the impeller of a multi-stage pump. The upper portion of each impeller would be disposed within a liquid-sealing chamber and the lower portion of that impeller would be disposed within a pressuregenerating chamber. The pressure-generating chamber of the first impeller would be connected to the inlet chamber of the next succeeding impeller; and the inlet chamber of that first impeller would be connected to a source of hydraulic fluid, while the pressure-generating chamber of the last impeller would be connected to a pressure-actuated device. The pressure in the inlet chamber of the last impeller would be substantially higher than the pressure in the inlet chamber of the first impeller, but the pressure in the inlet chamber of that last impeller would be substantially smaller than the pressure in the pressure-generating chamber of that last impeller.

If desired, the anti-friction bearing 28 and 30 could be replaced by friction bearings. Also, if desired, thrust bearings could be used in lieu of or in addition to those anti-friction bearings. Because all anti-friction bearings v provide some resistance to thrust, thrust bearings are not needed where the impellers are relatively small; but, where those impellers are large, the action forces applied to the bottom of the shroud 63 and the reaction forces applied to the impeller 60 by the liquid in the liquid-sealing and pressure-generating chambers will add and will apply such a large upwardly-acting, axially-directed force to the shaft 26 that one or more thrust bearings should be used to compensate for it.

Where large impellers 60 are used, more than ten impeller blades 62 will be used and more than one annular separator 66 will be used. Where more than one annular separator is used, the inner annular separator should extend above the level of the outer annular separator; and the annular area between the upper edges of the annular separators should be as large as the annular area between the lower edges of those annular separators. In all events, the upper edges of the liquid passages defined by the impeller blades 62 will be substantially-completely open to assure full and free flow of liquid into those liquid passages.

The liquid seal provided in each of the embodiments of hydraulic power unit shown in the drawing will be maintained even if the spacing between the outer ends of the impeller blades 62 and the inner surface of the liquidsealing chamber increases materiallyas it may, due to the abrading action of sand and other foreign matter in the water passing through the liquid-sealing chamber. For example, while the initial spacing between the outer ends of the impeller blades 62 and the frusto-conical surface 42 of the liquid-sealing chamber will preferably be three thousandths of an inch, the liquid seal provided by that liquid-sealing chamber will be maintained even if the spacing between the outer ends of the impeller blades 62 and the frusto-conical surface 42 increases to as much as ten thousandths of an inch. This is in strong contrast to hydraulic power units which rely upon high-pressure mechanical seals; because high-pressure mechanical seals lose their effectiveness when they wear even just a few thousandths of an inch.

Whereas the drawing and accompanying description have shown and described two preferred embodiments of the present invention it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I claim is:

1. A hydraulic power unit which comprises:

a liquid-sealing, pumping chamber having an outwardly diverging wall,

a pressure-generating chamber contiguous to and in communication with said liquid-sealing, pumping chamber, and

a rotatable impeller which has a plurality of blades and which is rotatable about a predetermined axis,

portions of said blades being disposed within said liquid-sealing, pumping chamber and having the outer edges thereof closely adjacent the inner surface of said liquid-sealing chamber and having said outer edges thereof spaced apart to define open spaces therebetween through which liquid flows outwardly to engage said inner surface of said liquid-sealing, pumping chamber,

other portions of said blades being disposed within said pressure-generating chamber,

said other portions of said blades responding to rotation of said impeller about said predetermined axis to develop liquid pressure within said pressure-generating chamber,

the first said portions of said blades being inclined laterally to said predetermined axis and responding to rotation of said impeller about said predetermined axis to develop forces on the liquid in said liquidsealing, pumping chamber which tend to cause said liquid to move along said predetermined axis toward said pressure-generating chamber, and said liquidsealing, pumping chamber having the inner surface thereof inclined inwardly toward said predetermined axis to tend to force said liquid which flows outwardly through said spaces between said outer edges of said first said portions of said blades to move along said predetermined axis toward said pressure-generating chamber, and thereby enable said liquid within said liquid-sealing, pumping chamber to provide a liquid seal that will minimize flow of liquid from said pressure-generating chamber along said predetermined axis to and through said liquid-sealing, pumping chamber,

whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid sealing, pumping chamber.

2. A hydraulic power unit as claimed in claim 1 wherein said inner surface of said liquid sealing, pumping chamber is a frusto-conical surface, said first said portions of said blades defining part of the surface of a theoretical cone which is concentric with said frustoconical inner surface and which has an angle of generation that is substantially equal to the angle of generation of said frusto-conical inner surface.

3. A hydraulic power unit which comprises:

a liquid-sealing, pumping chamber having an outwardly diverging wall,

a pressure-generating chamber, and

a rotatable impeller which has a plurality of blades,

portions of said blades being disposed within said liquid-sealing, pumping chamber,

other portions of said blades being disposed within said pressure-generating chamber,

said other portions of said blades responding to rotation of said impeller to develop liquid pressure within said pressure-generating chamber,

the first said portions of said blades responding to rotation of said impeller to develop forces on the liquid in said liquid-sealing, pumping chamber which enable said liquid to provide a liquid seal that will minimize flow of liquid from said pressure-generating chamber to and through said liquid-sealing, pumping chamber,

whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid sealing, pumping chamber,

said blades defining liquid passages through said impeller that have lower portions which are wider than the upper portions of said liquid passages,

the larger widths of said lower portions of said liquid passages fostering and enhancing movement of liquid downwardly through said upper portions of said liquid passages.

4. A hydraulic power unit which comprises:

a liquid-sealing, pumping chamber having an outwardly diverging wall,

a pressure-generating chamber contiguous to and in communication with said liquid-sealing, pumping chamber, and

a rotatable impeller which has a plurality of blades and which is rotatable about a predetermined axis,

portions of said blades being disposed within said liquidsealing, pumping chamber and having the outer edges thereof closely adjacent the inner surface of said liquid-sealing chamber and having said outer edges thereof spaced apart to define open spaces therebetween through which liquid flows outwardly to engage said inner surface of said liquid-sealing, pumping chamber,

other portions of said blades being disposed within said pressure-generating chamber,

said other portions of said blades responding to rotation of said impeller about said predetermined axis to develop liquid pressure within said pressure-generating chamber,

the first said portions of said blades being inclined laterally to said predetermined axis and responding to rotation of said impeller about said predetermined axis to develop forces on the liquid in said liquidsealing, pumping chamber which tend to cause said liquid to move along said predetermined axis toward said pressure-generating chamber, and said liquidsealing, pumping chamber having the inner surface thereof inclined inwardly toward said predetermined axis to tend to force said liquid which flows outwardly through said spaces between said outer edges of said first said portions of said blades to move along said predetermined axis toward said pressure-generating chamber, and thereby enable said liquid within said liquid-sealing, pumping chamber to provide a liquid seal that will minimize flow of liquid from said pressure-generating chamber along said predetermined axis to and through said liquid-sealing, pumping chamber,

whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid-sealing, pumping chamber,

said other portions of said blades being generally parallel to said predetermined axis,

the lateral inclinations of said first said portions of said blades making the widths of the upper portions of the liquid passages defined by said blades smaller than the widths of the lower portions of said liquid passages.

5. A hydraulic power unit as claimed in claim 1 wherein said other portions of said blades have convex, axiallydirected parts adjacent the outer ends thereof that apply outwardly-directed thrusts to the liquid in said pressuregenerating chamber.

6. A hydraulic power unit as claimed in claim 1 wherein the outer edges of said blades are longer than the spaces between said outer edges of said blades, and wherein said first said portions of said blades lap parts of said other portions of the next-preceding blades.

7. A hydraulic power unit which comprises:

a liquid-sealing, pumping chamber having an outwardly diverging wall,

a pressure-generating chamber, and

a rotatable impeller which has a plurality of blades,

portions of said blades being disposed within said liquidsealing, pumping chamber,

other portions of said blades being disposed within said pressure-generating chamber,

said other portions of said blades responding to rotation of said impeller to develop liquid pressure within said pressure-generating chamber,

the first said portions of said blades responding to rotation of said impeller to develop forces on the liquid in said liquid-sealing, pumping chamber which enable said liquid to provide a liquid seal that will minimize flow of liquid from said pressure-generating chamber to and through said liquid-sealing, pumping chamber,

whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid-sealing, pumping chamber,

the outer ends of the leading faces of said blades inclining upwardly and rearwardly relative to the adjacent areas of said blades,

said upwardly and rearwardly inclined outer ends of said leading faces providing outward thrusts on the liquid adjacent the periphery of said impeller.

8. A hydraulic power unit as claimed in claim 1 wherein the outer ends of the leading faces of said blades incline upwardly and rearwardly relative to the adjacent areas of said blades to provide outward thrusts on the liquid adjacent the periphery of said impeller, and wherein the upwardly and rearwardly inclined outer end of the leading face of each blade is generally parallel to part of the leading face of the next-succeeding blade.

9. A hydraulic power unit which comprises:

a liquid-sealing, pumping chamber having a diverging wall,

a pressure-generating chamber, and

a rotatable impeller which has a plurality of blades,

portions of said blades being disposed within said liquidsealing, pumping chamber,

other portions of said blades being disposed within said pressure-generating chamber,

said other portions of said blades responding to rotation of said impeller to develop liquid pressure within said pressure-generating chamber,

the first said portions of said blades responding to rotation of said impeller to develop forces on the liquid in said liquid-sealing, pumping chamber which enable said liquid to provide a liquid seal that will minimize How of liquid from said pressure-generating chamber to and through said liquid-sealing, pumping chamber,

whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid-sealing, pumping chamber,

said impeller being rotatable about a predetermined axis,

an annular separator extending between the confronting faces of said blades to define an inner annular area and an outer annular area for said impeller,

said inner annular area having liquid passages therethrough defined by said blades,

said liquid passages being wider adjacent the bottoms thereof than they are adjacent the tops thereof to foster and enhance the movement of liquid into and through said liquid passages,

said annular separator having a leading edge and a trailing edge,

said leading edge of said annular separator being disposed radially outwardly of said trailing edge of said annular separator so said annular separator will guide liquid inwardly toward said predetermined axis.

10. A hydraulic power unit which comprises:

a liquid-sealing, pumping chamber having an outwardly diverging wall,

a pressure-generating chamber, and

a rotatable impeller which has a plurality of blades,

portions of said blades being disposed within said liquidsealing, pumping chamber,

other portions of said blades being disposed within said pressure-generating chamber,

said other portions of said blades responding to rotation of said impeller to develop liquid pressure within said pressure-generating chamber,

the first said portions of said blades responding to rotation of said impeller to develop forces on the liquid in said liquid-sealing, pumping chamber which enable said liquid to provide a liquid seal that will minimize flow of liquid from said pressure-generating chamber to and through said liquid-sealing, pumping chamber,

whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid-sealing, pumping chamber,

said impeller being rotatable about a predetermined axis,

an annular separator extending between the confronting faces of said blades to define an inner annular area and an outer annular area for said impeller,

each of said annular areas having liquid passages therethrough defined by said blades,

a housing that encloses said impeller,

said annular separator extending a substantial distance upwardly above said first said portions of said blades and coacting with an adjacent liquid-guiding surface on said housing to guide liquid into said inner annular area,

said annular separator having a leading edge and a trailing edge,

said leading edge of said annular separator being disposed radially outwardly of said trailing edge of said annular separator so said annular separator will guide liquid inwardly toward said predetermined axis.

11. A hydraulic power unit which comprises:

a liquid-sealing, pumping chamber having an outwardly diverging wall,

a pressure-generating chamber, and

a rotatable impeller which has a plurality of blades,

portions of said blades being disposed within said liquid-sealing, pumping chamber,

other portions of said blades being disposed within said pressure-generating chamber,

said other portions of said blades responding to rotation of said impeller to develop liquid pressure within said pressure-generating chamber, the first said portions of said blades responding to rotation of said impeller to develop forces on the liquid in said liquid-sealing, pumping chamber which enable said liquid to provide a liquid seal that will minimize flow of liquid from said pressure-generating chamber to and through said liquid-sealing, pumping chamber, whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid-sealing, pumping chamber, said impeller being rotatable about a predetermined axis, an annular separator extending between the confronting faces of said blades to define an inner annular area and an outer annular are for said impeller, each of said annular areas having liquid passages therethrough defined by said blades, said annular separator having the lower edge thereof disposed below the upper edges of said blades but above the lower edges of said blades, whereby liquid can pass below said lower edge of said annular separator and outwardly between the ends of said blades, said annular separator having a leading edge and a trailing edge, said leading edge of said annular separator being disposed radially outwardly of said trailing edge of said annular separator so said annular separator will guide liquid inwardly toward said predetermined axis, said trailing edge of said annular separator extending generally parallel to said predetermined axis to guide liquid in a generally axial direction toward said lower edges of said blades. 12. A hydraulic power unit which comprises: a rotatable impeller that has a hub, a plurality of blades that extend outwardly from, but

that rotate with, said hub, and a housing for said impeller that encloses said impeller and that is disposable in water having weeds, moss, grass and other foreign matter in it, said housing having a V-shaped front with sides that coact to subtend an acute angle and thereby enable said V-shaped front to guide weeds, moss, grass and other foreign matter around it rather than to permit said weeds, moss, grass and other foreign matter to lodge upon it, said V-shaped front being perforate to permit water to pass through it and thereby enter said housing, said housing being part of a propulsive unit for a boat, said impeller providing propulsive forces for said boat. 13. A hydraulic power unit as claimed in claim 10 wherein said housing has a concave wall at the interior thereof which confronts the lower portions of said blades and which merges into the wall of said liquid sealing, pumping chamber, and wherein said concave wall extends outwardly an appreciable distance beyond the outer ends of said blades to define an annular passage for liquid moving circumferentially of said impeller.

14. A hydraulic power unit which comprises: a liquid-sealing, pumping chamber having an outwardly diverging wall, a pressure-generating chamber, and a rotatable impeller which has a plurality of blades, portions of said blades being disposed within said liquidsealing, pumping chamber, other portions of said blades being disposed within said pressure-generating chamber, said other portions of said blades responding to rotation of said impeller to develop liquid pressure within said pressure-generating chamber,

the first said portions of said blades responding to rotation of said impeller to develop forces on the liquid in said liquid sealing, pumping chamber which enable said liquid to provide a liquid seal that will minimize flow of liquid from said pressure-generating chamber to and through said liquid-sealing, pumping chamber,

whereby said hydraulic power unit can develop liquid pressure in said pressure-generating chamber despite the absence of high-pressure mechanical seals between the blades and the wall of the liquid-sealing, pumping chamber,

a bafile in said pressure-generating chamber extending toward but stopping short of said impeller, and

the forward face of said bafile defining a pocket into which the liquid in the spaces between said impeller blades can readily flow after said spaces move forwardly of said bafile.

References Cited UNITED STATES PATENTS Fowle 230-434 Pavlecka et al.

Concordia et al. 230--134 Seinfeld.

Tinker 11516 Mock et al. 103-88 Craig 60222 HENRY F. RADUAZO, Primary Examiner U.SL C1. X.R.

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