Waterjet propulsion system for surface transport vessels

Abstract

A mixed-flow waterjet pump used to propel ships and other watercraft. The jet pump may be of a fixed configuration or may have an intake section and a flexible intake extension to allow trimming capabilities, where the main input drive shaft does not pass through the jet pump intake. The jet pump may include a dual or single input drive shaft system, allowing greater power to be transferred to the pump through a dual shaft input drive mechanism while maintaining reliability. The jet pump may be of an inboard or outboard configuration, using an internal combustion engine or an electric motor as the primary drive means.

Description

[Technical Field]

[0001] The present invention relates to a water jet propulsion device for use on power-propelled ships and other water vehicles. [Background technology]

[0002] Canadian Patent Publication No. 2,698,429 (Davies) describes waterjet propulsion pumps in outboard configurations where the outboard powerhead is mounted externally on the transom of the vessel, or inboard-outboard configurations where the drive engine is located within the surface vessel by the attachment of a bevel gear right-angle drive. It also describes a number of prior patented machines that were not commercially successful due to poor performance or failure to meet basic functional requirements such as trim adjustment and maintainability.

[0003] A prior patent, U.S. Patent No. 3,082,732 (Stallman), describes a commercially available outboard motor configuration with a centrifugal pump mounted on a powerhead. While this jet pump meets many practical customer requirements, it lacks the performance required for larger watercraft applications. This device provides steering and trim adjustment and is transom-mounted on the outboard motor configuration.

[0004] U.S. Patent No. 5,769,674 (Stallman) describes another jet pump for use on an outboard motor, but this example uses an axial configuration that partially resembles the configuration of an outboard motor's lower legs inserted into an outer casing. This device suffers from problems with the upstream structure that degrades overall performance, and therefore has not been commercially accepted and is not currently on the market.

[0005] U.S. Patent No. 4,281,996 (Mouraret) shows a simple outboard jet pump design with a vertical drive shaft extending to a drive gear downstream of the stator section and a gear portion within the flowpath. This patent does not address the hydrodynamic requirements associated with this type of design, primarily the centrally mounted intake pivoting away from the transom when in a tilted position. This results in multiple changes of direction within the flowpath when the boat is planing, causing the jet nozzle to rise significantly above the waterline, resulting in unnecessary pressure loss to the pump.

[0006] The jet pump described in U.S. Patent No. 6,267,632 (Blanchard) provides many features needed in the marketplace, but does not address the key issues with pump performance, particularly stator construction, as seen in the Canadian publication cited above.

[0007] U.S. Patent No. 6,776,674 (Blanchard) attempts to improve the performance of an outboard jet pump concept, essentially a conventional axial jet pump mounted to the boat's transom by a single rotary joint. This concept lacks the compactness of a conventional outboard propeller system that incorporates both trim adjustment and steering functions. Furthermore, its main input drive shaft is located within the intake portion of the flowpath.

[0008] As described below, further improvements allow for greater reliability and increased drive input than previously described, resulting in a simplified trim adjustment system. Furthermore, improvements are described, such as the use of a mixed-flow impeller, which utilizes radially induced energy more efficiently and provides a means for better control of the flow through the intake. This is achieved by adjusting the jet pump by adjusting the ratio of the impeller's inlet area to its downstream outer area. This provides a means for adjusting the flow delivered from the intake, reducing the upstream diameter of the impeller and, consequently, the size and cross-sectional area of ​​the intake's outlet. When the vessel is planing on the water, the size of the intake is reduced, thereby reducing the amount of water drawn into the vessel. This seemingly simple change means that the impeller's shape, particularly with regard to pitch (helix angle), can be advantageously designed, making the upstream diameter smaller than its downstream end and allowing for a larger pitch width between the leading and trailing edges of the impeller. The mixed flow design principle is currently being adopted by jet pump manufacturers, where the main input drive shaft is inserted axially into the intake section.

[0009] The Canadian Patent Publication shows a single, vertically-oriented drive shaft passing through the stator of the jet pump, which is necessarily limited in diameter by the need to make the stator vanes through which it passes as thin as possible while still maintaining a suitable hydrodynamic profile. These constraints affect both the hydrodynamic characteristics of the flow through the pump and the power or torque that can be safely applied to the shaft.

[0010] To overcome these two challenges, two counter-rotating vertical shaft input drive shafts are shown, interconnected by two meshing gears and passing through the same single stator vane. Figure 1 shows bevel gears attached to the lower ends of the shafts. This allows the two input shafts to each share approximately 50% of the power transmitted from the drive engine, increasing the available power input while maintaining the overall width of the stator vane without incurring additional hydrodynamic losses. The improved dual shaft configuration allows for increased power input, making it suitable for use on larger vessels. For example, the jet pump shown in Figure 3 can be configured as an outboard motor mounted on the stern of a commercial 30-meter planing boat using a gas turbine or large electric motor as the powerhead.

[0011] With respect to the jet pump shown in FIG. 1, a means of improving pump efficiency through improvements to the impeller housing and impeller is shown, where the impeller has a tapered outer periphery that corresponds to the shape of the outer casing or impeller housing, adopting a "mixed flow" shape.

[0012] As a further improvement, the impeller housing has two mounting pins located within two rotatable mounting points located inside two recesses in the transom wall. A third mounting is also provided by a right-angle drive or ram mounted on the transom.

[0013] A flexible sleeve connects the intake section to the impeller housing, allowing the impeller housing / gearbox stator to tilt up and down independently of the intake housing. By removing one half of the sleeve fixing clamp, the grooved fixing plate, and the ram connection, the entire impeller housing / gearbox stator and power head can be removed as a unit for maintenance.

[0014] Such an arrangement, as shown in Figure 8, allows for an efficient trim system, but does not provide the steering capabilities of the aforementioned Canadian published patent. An electric or hydraulic ram mounted on the transom, right-angle gearbox, or outboard motor leg casing can be remotely operated, allowing rotation of the entire unit independent of the intake, facilitating adjustment of the boat's trim.

[0015] Thrust is directed towards the transom rather than the intake, which is important as the intake is no longer subjected to thrust, allowing for a lighter construction. The problem of foreign matter (debris) ingress in the intake grille is also addressed by a relatively low-loss intake cleaning system, with the intake cleaning device being located outside the intake flow path. The concept of an intake cleaning system is not new and such systems are already in use on the market today, with cleaning bars attached to the intake grille.

[0016] U.S. Patent No. 11,097,821 (Schultz) describes an intake cleaning system in which a set of interconnected grille cleaning bars descends through fixed intake grille bars secured to the Stallman centrifugal jet pump for an outboard motor. When not in operation, the cleaning bars reside between the fixed bars and are still in the main intake flow, yet still serve to reduce grille clogging. The present invention differs in that the cleaning bar is located outside the flow path of the intake section, which is not achieved at all in the grill cleaning systems of jet pumps with axially arranged shafts or centrifugal jet pumps for Stallman outboard motors mentioned above. [Prior art documents] [Patent documents]

[0017] [Patent Document 1] Canadian Patent Publication No. 2,698,429 [Patent Document 2] U.S. Patent No. 3,082,732 [Patent Document 3] U.S. Patent No. 5,769,674 [Patent Document 4] U.S. Patent No. 4,281,966 [Patent Document 5] U.S. Patent No. 6,267,632 [Patent Document 6] U.S. Patent No. 6,776,674 [Patent Document 7] U.S. Patent No. 11,097,821 Summary of the Invention

[0018] The present invention further improves jet pump performance, allowing for a higher power input than that described in the aforementioned Canadian Patent Publication, while maintaining the advantages of ease of maintenance and ease of installation on any vessel. To achieve this increased power input, a dual-shaft input system is described in which the main drive mechanism is split into two, with the impeller shafts driven by a set of bevel gears that drive in the same direction. This is accomplished without excessive hydrodynamic losses by passing two vertical shafts through a single improved stator vane, thereby maintaining the right-angle drive and outboard motor configuration.

[0019] Furthermore, a variant solution using two vertical shafts is described, in which the speed of the impeller drive shaft can be adjusted by changing the gear ratio of one to the other, although this reduces the possibility of a higher power input. This means that the gear ratio of the main drive input can be changed without changing the gear ratio of the bevel gear of the impeller drive shaft. Importantly, this feature ensures an optimal size for the gear of the bevel gear of the impeller drive shaft, without requiring, for example, a bevel pinion with fewer teeth and therefore a lower load capacity.

[0020] Regarding pump performance, we are also working on a mixed-flow configuration for the impeller and impeller housing. While this concept is not new, it can be used more effectively in situations where there is no drive input shaft in the main axial direction of the jet pump intake. This is possible because the tip of the impeller can extend to the upstream apex of the impeller boss. This allows for greater freedom in adjusting the impeller diameter and impeller blade tip position, making it easier to adjust the upstream flow being sucked in.

[0021] One of the main disadvantages of jet pumps compared to propeller-driven devices such as outboard motors is the risk of clogging (blockage) in the intake section. This problem has traditionally been overcome to some extent by providing a fixed grill bar in the intake section. Removing waterborne weeds has proven inefficient, and many manufacturers have adopted the use of a grill cleaning bar, but this approach has been limited by the presence of an axially aligned shaft in the intake section. The absence of an axial shaft in the intake section of this invention allows for a drop-type cleaning screen with an operating lever or plunger mounted in the center of an oscillating grill, free from interference from the drive shaft. When retracted, the grill bars and fingers are positioned within individual recesses in the ceiling of the intake section. This completely removes the bars from the intake flow, resulting in a relatively smooth surface.

[0022] In the currently manufactured machines described below, nozzle steering and deflector reversal systems have been omitted to simplify the description of each device.

[0023] In summary, the following points are addressed: (i) The ability to increase power input using a stronger drive train while maintaining pump performance. (ii) Improved pump performance and input flow rate due to the use of mixed flow geometry in the impeller and impeller housing. (iii) The ability to adjust the impeller drive speed without changing the bevel gear. (iv) Simplification of the trim system. (v) Adopts an improved intake grill cleaning system. [Brief explanation of the drawings]

[0024] [Figure 1] Figure 1 is an isometric cutaway view of a jet pump aft mixed flow drive showing a dual-shaft input configuration including a right-angle drive, a single mixed flow impeller, and a main input shaft. In the dual-shaft input configuration, input power is shared with an additional shaft through two meshed gears, both of which pass perpendicularly through the improved stator vanes shown in Figure 6. The two shafts in turn drive four interconnected bevel gears located within the gearbox casing, and their combined input torque rotates the impeller shaft. [Figure 2] Figure 2 is an isometric cutaway view of the aft mixed flow drive of a jet pump, showing the right-angle drive, single mixed flow impeller, and bevel gear. The gear train includes an input vertical shaft with a gear attached to its lower end that meshes with a second gear, allowing the gear ratio to be changed as needed. The second gear is attached to an adjacent second vertical shaft that runs perpendicularly through the improved stator vane shown in Figure 7. The second vertical shaft has a bevel gear attached to its lower end that meshes with a second bevel gear attached to the impeller drive shaft. [Figure 3] Figure 3 shows a side elevation view of an outboard mixed-flow jet pump with a single mixed-flow impeller and a dual-shaft input configuration including a main input shaft. In the dual-shaft input configuration, input power is shared with an additional shaft via two meshed gears, both of which run perpendicular to the improved stator vanes shown in Figure 6. The two shafts in turn drive four interconnected bevel gears mounted within the gearbox casing, and their combined input torque rotates the impeller shaft. Also shown is the jet pump's vertically movable mechanism, allowing the impeller housing / gearbox-stator assembly to swing up and down, thereby enabling boat trim adjustment. [Figure 4]Figure 4 is an exploded side elevation view of an outboard mixed flow jet pump with a single mixed flow impeller, showing the intake with a movable grill cleaning device with a bar that descends between the fixed intake grill bars but is housed in a recess in the intake ceiling upstream to minimize hydrodynamic losses. [Figure 5] FIG. 5 is an isometric cutaway view of a jet pump showing the mixed flow impeller housing and intake section, as well as the movable arrangement (pivot mechanism) that allows the impeller housing / gearbox stator section to swing up and down independently of the intake section. [Figure 6] FIG. 6 is a cutaway isometric view of a jet pump stator showing the improved stator vanes and two vertical holes (longitudinal holes) for passing two vertical input drive shafts to the lower gear case. [Figure 7] FIG. 7 is a cutaway isometric view of a jet pump stator showing an improved stator vane with one vertical hole (longitudinal hole) for passing one vertical input shaft through to the lower gear case. [Figure 8] FIG. 8 is a diagram showing the jet pump intake portion and the intake grill showing means for removing foreign matter (dust) between the fixed intake grill bars. DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 shows a mixed-flow jet pump with an intake section 1 having a tapered impeller housing 2 fixed directly to its downstream end. The impeller housing 2 has a stator / gearbox section 3, a right-angle drive 4 mounted on top of it, and a nozzle 5 fixed thereto. A mixed-flow impeller 6 is shown disposed within the impeller housing 2. The jet pump includes a main input drive shaft 7 connected to a vertical drive shaft 8 via bevel gears 9 and 10. The vertical drive shaft 8 is connected to a lower vertical shaft 11 via mating splines (not shown). The lower vertical shaft 11 carries a gear 12 that meshes with a gear 13 mounted on a lower vertical shaft 14. Each vertical shaft 11 and 14 passes through holes 15 and 16 in a modified stator vane 17, clearly shown in FIG. 6. Bevel gears 18 and 19 are attached to the lower ends of the shafts 11 and 14, and the bevel gears 18 and 19 mesh with bevel gears 20 and 21. The bevel gears 20 and 21 are attached to an impeller shaft 22 and are driven together to rotate the shaft 22 in the same direction. This gear train can increase the power input of the jet pump.

[0026] FIG. 2 shows a similar jet pump with a top-mounted right-angle drive input 23 but with a different gear train arrangement. This mixed-flow jet pump includes an intake section 24 with a tapered impeller housing 25 fixed directly to its downstream end. The impeller housing 25 has a stator / gearbox section 26, with the right-angle drive input 23 fixed to its top. A mixed-flow impeller 27 is shown positioned within the impeller housing 25. The jet pump includes a main input drive shaft 28 connected to a vertical drive shaft 29 via bevel gears 30 and 31. The vertical drive shaft 29 is connected to a short lower vertical shaft 32 via mating splines (not shown). A gear 33 mounted on the lower vertical shaft 32 meshes with a gear 34 mounted on a second lower vertical shaft 35. The gear ratio of the gears 33 and 34 is adjustable to change the rotational speed of the impeller drive shaft 41 as needed. Shaft 35 passes through a single hole 36 in a modified stator vane 37 (clearly shown in Figure 7) and is inserted into a lower gear case 38. A bevel gear 39 attached to the lower end of shaft 35 meshes with a bevel gear 40 attached to an impeller drive shaft 41.

[0027] 3 shows a twin-shaft configuration outboard mixed flow jet pump including an intake section 42, an impeller housing 43, a single mixed flow impeller 44, a stator / gearbox section 45, a nozzle 46, and an outboard motor power head 47. The rest of the power transmission mechanism is the same as that shown in FIG.

[0028] FIG. 4 shows an outboard mixed flow jet pump with a simplified drive train that incorporates a trim adjustment mechanism and grill cleaning system to raise and lower the nozzle 53 relative to the intake section 48, while still requiring fewer gears. The major components are shown separated for clarity. The jet pump includes the intake section 48, flexible sleeve 49, impeller housing 50, mixed flow impeller 51, stator / gearbox section 52, nozzle 53, and outboard power head 54. A single main input shaft 55 is also included, which transmits power to the stator / gearbox section 52. The shaft 55 passes through a single hole 56 in a modified stator vane 57, also shown as 36 and 37 in FIG. 7, and is inserted into a lower gearbox casing 58. The shaft 55 has a bevel gear 59 attached to its lower end, which meshes with a bevel gear 60 attached to an impeller shaft 61.

[0029] Also shown in Figure 4 is a retractable grill cleaning system, also shown in Figure 8. In this system, spaced apart grill bar fingers 62 (finger-like grill bars) are secured to the upstream end of a fixed intake grill 64 by hinges 63, allowing them to swing down (65) from recesses 66 in the upper ceiling 67 of the intake section 48 and into the fixed intake grill 64. An actuating rod 68 allows manual or remote operation of the bar fingers 62, thereby clearing weeds and other debris (debris) from the intake grill 64. Drop-down intake grill cleaning systems are currently commercially available, but for jet pumps with a drive shaft through the intake, a hinged grill is attached to the underside of a fixed intake grill. When in operation, the hinged grill rotates down between the fixed grill bars to clear debris below the bottom line. However, this design places the bar fingers 62 outside the intake flow path when not in use due to the presence of the recesses 66. Since there is no axial drive shaft, the rod 68 is centered.

[0030] The isometric cross-sectional view of Figure 5 shows the trim adjustment mechanism shown in Figure 4 in more detail. In Figure 5, impeller housing 69 is independently attached to transom housing 70 via pivot pin 71 and a second pin (not shown), allowing the pump output thrust to be transmitted to transom housing 70. Ram 72, also shown in Figure 4, is attached to transom 73 and upper gear case 74, also shown in Figure 4, thereby enabling remote control of vertical movement 75, also shown as 65 in Figures 5 and 4. Pivot pin 71 and its counterpart (not shown) are inserted into keyway(s) 76 and retainer 77, and secured by fastener plate 78 and bolts 79 and 80.

Claims

1. The intake section, a mixed flow impeller housing; A mixed flow impeller; A stator gearbox section, Right-angle gearbox, a nozzle fixed to the stator gearbox section; Equipped with the right-angle gearbox and the stator gearbox section comprise a gear train; the gear train includes a main input shaft connected to a vertical input shaft via two intermeshing bevel gears, the vertical input shaft being connected to a lower shaft via mating splines; The lower shaft has a gear attached to its upper end, and the gear meshes with a gear attached to the upper end of the adjacent lower vertical shaft; the lower shaft and the lower vertical shaft both enter a lower gear case through two holes in a single hydrodynamically improved stator vane; The lower shaft and the lower vertical shaft each have a bevel gear attached to their lower ends, and the bevel gears of the lower shaft and the lower vertical shaft mesh with two more bevel gears attached to an impeller drive shaft; Both the lower shaft and the lower vertical shaft transmit power or torque equally to the impeller drive shaft; 1. A mixed flow waterjet pump, wherein the intake section, the mixed flow impeller housing, the stator / gearbox section, the nozzle, and the right-angle drive are fixed to one another.

2. The intake section, a mixed flow impeller housing; A mixed flow impeller; A stator gearbox section, Right-angle gearbox, a nozzle fixed to the stator gearbox section; Equipped with the right-angle gearbox and the stator gearbox section comprise a gear train; the gear train includes a main input shaft connected to a vertical input shaft via two intermeshing bevel gears, the vertical input shaft being connected to a lower shaft via mating splines; The lower shaft has a gear attached to its upper end, and the gear meshes with a gear attached to the upper end of the adjacent lower vertical shaft; the gear of the lower shaft and the gear of the lower vertical shaft are replaceable with gears having different gear ratios; the lower vertical shaft is inserted into the lower gear case through a single hole in the hydrodynamically improved vane; The lower vertical shaft has a bevel gear attached to its lower end, The bevel gear meshes with a bevel gear attached to an impeller shaft, 1. A mixed flow waterjet pump, comprising: an intake section, a mixed flow impeller housing, a stator / gearbox section, a nozzle, and a right-angle gearbox, the intake section, the mixed flow impeller housing, the stator / gearbox section, the nozzle, and the right-angle gearbox being fixed to one another.

3. The intake section, a mixed flow impeller housing; A mixed flow impeller; Stator gearbox section and a nozzle fixed to the stator gearbox section; an outboard motor power head fixed to the stator gearbox section; Equipped with the stator gearbox has a gear train; the gear train includes a vertical input shaft; the vertical input shaft is connected to the outboard motor power head; The vertical input shaft is connected to the lower shaft via a mating spline; The lower shaft has a gear attached to its upper end, and the gear meshes with a gear attached to the upper end of the adjacent lower vertical shaft; the lower shaft and the lower vertical shaft both enter a lower gear case through two holes in a single hydrodynamically improved stator vane; The lower shaft and the lower vertical shaft each have a bevel gear attached to their lower ends, The bevel gears on the lower shaft and the lower vertical shaft mesh with two more bevel gears attached to an impeller drive shaft; Both the lower shaft and the lower vertical shaft transmit power or torque equally to the impeller drive shaft; 1. A mixed flow waterjet pump, wherein the intake section, the mixed flow impeller housing, the stator / gearbox section, the nozzle, and the outboard motor power head are fixed to one another.

4. The intake section, a mixed flow impeller housing; A mixed flow impeller; a flexible sleeve secured to the intake portion and the mixed flow impeller housing; Stator gearbox section and a nozzle fixed to the stator gearbox section; an outboard motor power head fixed to the stator gearbox section; Equipped with the outboard motor power head is connected to the stator gearbox section via a vertical input drive shaft that is coupled to a gear train via mating splines; the gear train includes a vertical lower shaft; The vertical lower shaft has a gear attached to its upper end, and the gear meshes with a gear attached to the upper end of an adjacent vertical lower shaft; the vertical lower shaft and the adjacent vertical lower shaft are inserted into a lower gear case through two holes in a hydrodynamically improved vane; the vertical lower shaft and the adjacent vertical lower shaft each have a bevel gear attached to a lower end thereof; the bevel gears on the vertical lower shaft and the adjacent vertical lower shaft mesh with two more bevel gears attached to an impeller drive shaft; the vertical lower shaft and the adjacent vertical lower shaft transmit power or torque equally to the impeller drive shaft; the mixed flow impeller housing connects to the transom of the vessel via two fulcrum pins and a ram; the mixed flow impeller housing is fixed at its downstream end to the stator / gearbox section; Thus, the outboard motor power head, the stator / gearbox section, and the mixed flow impeller housing are integrally connected to the intake section via the flexible sleeve, the fulcrum pin, and the ram, and are capable of tilting up and down for trim adjustment.

5. The intake section, a mixed flow impeller housing; A mixed flow impeller; a flexible sleeve attached to the intake portion and the mixed flow impeller housing; A stator gearbox section, Right-angle gearbox, a nozzle fixed to the stator gearbox section; a gear train including a main input shaft connected to a vertical input shaft via two meshing bevel gears; Equipped with The vertical input shaft is connected to the lower shaft via a mating spline; The lower shaft has a gear attached to its upper end, and the gear meshes with a gear attached to the upper end of an adjacent vertical lower shaft; the lower shaft and the lower vertical shaft both enter a lower gear case through two holes in a single hydrodynamically improved stator vane; The lower shaft and the lower vertical shaft each have a bevel gear attached to their lower ends, The bevel gears on the lower shaft and the lower vertical shaft mesh with two more bevel gears attached to an impeller drive shaft; Both the lower shaft and the lower vertical shaft transmit power or torque equally to the impeller drive shaft; the mixed flow impeller housing connects to the transom of the vessel via two fulcrum pins and a ram; The right-angle gearbox, the stator gearbox section, and the mixed flow impeller housing are connected as a unit to the intake section via the flexible sleeve, the fulcrum pin, and the ram, and are tiltable up and down for trim adjustment.

6. The intake section, a mixed flow impeller housing; A mixed flow impeller; the flexible sleeve attached to the intake portion and the mixed flow impeller housing; Stator gearbox section and a nozzle fixed to the stator gearbox section; an outboard motor power head fixed to the stator gearbox section; Equipped with The outboard motor power head is connected to the stator gearbox assembly via a main vertical input shaft that is coupled to a gear train via mating splines. the gear train includes a vertical lower shaft; the vertical lower shaft is inserted into the lower gear case through a single hole in the hydrodynamically improved vane; The vertical lower shaft has a bevel gear attached to its lower end, and the gear meshes with a bevel gear attached to the impeller drive shaft, the impeller housing is connected to the transom of the vessel via two fulcrum pins and a ram; The power head, the stator / gearbox section, and the mixed flow impeller housing are connected as a unit to the intake section via the flexible sleeve, the fulcrum pin, and the ram, and are tiltable up and down for trim adjustment.

7. 7. A mixed flow water jet pump according to claim 1, wherein the intake section includes a movable grill cleaning device housed in a recess in the ceiling of the intake section of the water jet pump and connected by a hinge.

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