Water Jet Propulsion Unit for Water Borne Craft

Abstract

A mixed flow water jet pump used for propulsion in boats and other water borne craft. The jet pump may be a fixed assembly or alternatively in part comprise an intake section and flexible intake section extension allowing a trimming function and where the primary input drive shaft does not pass through the intake section of the jet pump. The jet pump drive may comprise a dual or single input drive shaft system where the dual input drive train allows for much greater power delivery to the pump while maintaining reliability. The jet pump may have a sterndrive or outboard configuration using internal combustion engines or electric motors as the primary driving means.

Claims

1. A mixed flow water jet pump comprising an intake section, mixed flow impeller housing, mixed flow impeller, stator-gearbox section, right-angle gearbox, a nozzle fixed to said stator-gearbox section, said right-angle gearbox and stator-gearbox section having a gear train where the said gear train comprises a primary input shaft coupled via two meshing bevel gears to a vertical input shaft, said vertical shaft being coupled via a mating spline to a lower shaft, said lower shaft having a gear fixed to its upper end that in turn meshes with a gear fixed to the upper end of an adjacent vertical lower shaft, and where both of the said lower shafts pass into the lower gear case through two holes in a single hydrodynamically modified stator blade, said lower shafts having bevel gears fixed to their lower ends, said bevel gears in turn meshing with two further bevel gears fixed to the impeller drive shaft and where both lower shafts transmit equal power or torque to the said impeller drive shaft, said intake section, mixed flow impeller housing, stator-gearbox section, nozzle and right-angle drive being fixed to one another.

2. A mixed flow water jet pump comprising an intake section, mixed flow impeller housing, mixed flow impeller, stator-gearbox section, right-angle gearbox, a nozzle fixed to said stator-gearbox section, said right-angle gearbox and stator-gearbox section having a gear train where the said gear train comprises a primary input shaft coupled via two meshing bevel gears to a vertical input shaft, said vertical shaft being coupled via a mating spline to a lower shaft, said lower shaft having a gear fixed to its upper end that in turn meshes with a gear fixed to the upper end of an adjacent vertical lower shaft, said gears being able to be substituted with gears of different ratios, said adjacent vertical shaft passing into the lower gear case through a single hole in a hydrodynamically modified stator blade, said shaft having a bevel gear fixed to its lower end, said bevel gear meshing with a bevel gear fixed to the impeller shaft, said intake section, mixed flow impeller housing, gearbox-stator section, nozzle and right-angle gearbox being fixed to one another.

3. A mixed flow water jet pump comprising an intake section, mixed flow impeller housing, mixed flow impeller, stator-gearbox section, a nozzle fixed to said stator-gearbox section, an outboard powerhead fixed to said stator-gearbox section, having a gear train where the said gear train comprises a vertical input shaft, said vertical shaft being connected to the said outboard powerhead, said vertical shaft being coupled via a mating spline to a lower shaft, said lower shaft having a gear fixed to its upper end that in turn meshes with a gear fixed to the upper end of an adjacent vertical lower shaft, and where both of the said lower shafts pass into the lower gear case through two holes in a single hydrodynamically modified stator blade, said lower shafts having bevel gears fixed to their lower ends, said bevel gears in turn meshing with two further bevel gears fixed to the impeller drive shaft and where both lower shafts transmit equal power or torque to the said impeller drive shaft, said intake section, mixed flow impeller housing, stator-gearbox section, nozzle and powerhead being fixed to each other.

4. A mixed flow water jet pump comprising an intake section, mixed flow impeller housing, mixed flow impeller, flexible sleeve fixed to said intake section and mixed flow impeller housing, stator-gearbox section, a nozzle fixed to said stator-gearbox section, an outboard powerhead fixed to the said stator-gearbox section, said outboard powerhead being connected to the stator-gearbox section via a vertical input drive shaft coupled via a mating spline to a gear train comprising a vertical lower shaft having a gear fixed to its upper end that in turn meshes with a gear fixed to the upper end of an adjacent vertical lower shaft, and where both of the said lower shafts pass into the lower gear case through two holes in a hydrodynamically modified stator blade, said lower shafts having bevel gears fixed to their lower ends, said bevel gears in turn meshing with two further bevel gears fixed to the impeller drive shaft and where both lower shafts transmit equal power or torque to the said impeller drive shaft, said mixed flow impeller housing being connected via two pivot pins and a ram to the water craft's transom, and where the said mixed flow impeller housing is fixed at its downstream end to the said stator-gearbox section whereby the said powerhead, stator-gearbox section and mixed flow impeller housing, being jointly connected to the intake section via the flexible sleeve, pins, and ram, may be rotated up and down for trimming purposes.

5. A mixed flow water jet pump comprising an intake section, mixed flow impeller housing, mixed flow impeller, flexible sleeve attached to said intake section and mixed flow impeller housing, stator-gearbox section, right-angle gearbox, a nozzle fixed to said stator-gearbox section, a gear train comprising a primary input shaft coupled via two meshing bevel gears to a vertical input shaft, said vertical shaft being coupled via a mating spline to a lower shaft, said lower shaft having a gear fixed to its upper end that in turn meshes with a gear fixed to the upper end of an adjacent vertical lower shaft, and where both of the said lower shafts pass into the lower gear case through two holes in a single hydrodynamically modified stator blade, said lower shafts having bevel gears fixed to their lower ends, said bevel gears in turn meshing with two further bevel gears fixed to the impeller drive shaft and where both lower shafts transmit equal power or torque to the said impeller drive shaft, said mixed flow impeller housing being connected via two pivot pins and a ram to the water craft's transom and where the said right-angle gearbox, stator-gearbox section and mixed flow impeller housing, being jointly connected to the intake section via the flexible sleeve, pins and ram may be rotated up and down for trimming purposes.

6. A mixed flow water jet pump comprising an intake section, mixed flow impeller housing, mixed flow impeller, flexible sleeve attached to said intake section and mixed flow impeller housing, stator-gearbox section, a nozzle fixed to said stator-gearbox section, an outboard powerhead fixed to the said stator-gearbox section, said powerhead being connected to the stator-gearbox section via a primary vertical input shaft that is coupled via a mating spline to a gear train comprising a vertical lower shaft, said vertical shaft passing into the lower gear case through a single hole in a hydrodynamically modified stator blade, said lower vertical shaft having a bevel gear fixed to its end, said bevel gear meshing with a bevel gear fixed to the impeller drive shaft, said impeller housing being connected via two pivot pins and a ram to the water craft's transom and where the said powerhead, stator-gearbox section and mixed flow impeller housing being jointly connected to the intake section via the flexible sleeve, pins and ram may be rotated up and down for trimming purposes.

7. A mixed flow water jet as claimed in claims 1-6 where the intake section may include a hinged pivoting grill cleaning device that retracts into a recess in the roof of the intake section of the water jet pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In the drawings are described the following:

[0012] FIG. 1: An isometric cut away view of a mixed flow stern drive version of the jet pump showing the right-angle drive, single mixed flow impeller, a dual shaft input configuration comprising a primary input shaft, where the input power is shared by an additional shaft via two meshed gears and where both shafts pass vertically through the modified stator blade as shown in FIG. 6. The two shafts in turn drive the four interconnected bevel gears mounted inside the gearbox casing where they together cause the impeller shaft to rotate under their combined input torques.

[0013] FIG. 2: An isometric cut away view of a mixed flow stern drive version of the jet pump showing the right-angle drive, single mixed flow impeller, where the gear train comprises a vertical input shaft with a gear fixed to its lower end, this gear being in mesh with a second gear, permitting a gear ratio change if required, the second gear being fixed to a second adjacent vertical shaft that passes vertically down through a modified stator blade, seen in FIG. 7, a bevel gear being fixed to its lower end that meshes with a second bevel gear fixed to the impeller drive shaft.

[0014] FIG. 3: Side elevation of a mixed flow outboard jet pump having a single mixed flow impeller, a dual shaft input configuration comprising a primary input shaft, where the input power is shared by an additional shaft via two meshed gears and where both shafts pass vertically through the modified stator blade as shown in FIG. 6. The two shafts in turn drive the four interconnected bevel gears mounted inside the gearbox casing where they together cause the impeller shaft to rotate under their combined input torques. Also shown is a method of jet pump articulation in the vertical plane, allowing the impeller housing/gearbox-stator section assembly to rotate up and down, thus allowing the craft to be trimmed while in planing mode.

[0015] FIG. 4: Side elevation of a mixed flow outboard jet pump having a single mixed flow impeller showing the major components separated. Also shown is an intake that contains a pivoting grill cleaning device comprising bars that lower down between the fixed intake section grill bars but that retract into a recess located in the upstream roof of the intake section so that hydrodynamic losses are minimised.

[0016] FIG. 5: An isometric cutaway view of the jet pump showing the mixed flow impeller housing, intake section and pivot arrangement that allows the impeller housing/gearbox-stator section to rotate up and down independent of the intake section.

[0017] FIG. 6: A cutaway isometric view of the jet pump stator showing the modified stator blade and the two vertical holes that allow for the two vertical input drive shafts to pass through into the lower gear case.

[0018] FIG. 7: A cutaway isometric view of the jet pump stator showing the modified stator blade with one vertical hole that allows for one vertical input shaft to pass through into the lower gear case.

[0019] FIG. 8: A view of the jet pump intake section and intake grill showing a means of removing debris from between the fixed intake grill bars.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0020] In FIG. 1 is shown a mixed flow jet pump having an intake section (1) with a tapered impeller housing (2) directly fixed to its downstream end. Further fixed to the impeller housing (2) is the stator-gearbox section (3) right-angle drive (4) fixed to its upper portion and a nozzle (5). A mixed flow impeller (6) is shown located inside the impeller housing (2). The jet pump has a primary input drive shaft (7) connected to the vertical drive shaft (8) via bevel gears (9) and (10). The vertical shaft (8) is connected to the lower vertical shaft (11) via mating splines (not shown) and where the lower vertical shaft (11) has a gear (12) fixed to it, that meshes with the gear (13) that is fixed to the lower vertical shaft (14). Vertical shafts (11) and (14) each pass through holes (15) and (16) shown in the modified stator blade (17) seen more clearly in FIG. 6. Shafts (11) and (14) have bevel gears (18) and (19) fixed to their lower ends, bevel gears (18) and (19) being in mesh with bevel gears (20) and (21). The gears (20) and (21) are fixed to the impeller shaft (22) and are jointly driven to rotate the shaft (22) in the same direction. This gear train thus allows an increased level of power input to be applied to the jet pump.

[0021] In FIG. 2 is shown a similar jet pump having a top mounted right-angle drive input (23) but with a different gear train arrangement. This mixed flow jet pump has an intake section (24) with a tapered impeller housing (25) directly fixed to its downstream end. Further fixed to the impeller housing (25) is the stator-gearbox section (26) and right-angle drive input (23) fixed to its upper portion. A mixed flow impeller (27) is shown located inside the impeller housing (25). The jet pump has a primary input drive shaft (28) connected to the vertical drive shaft (29) via bevel gears (30) and (31). The vertical shaft (29) is connected to the shortened lower vertical shaft (32) via mating splines (not shown) and where the lower vertical shaft (32) has a gear (33) fixed to it that meshes with the gear (34), that is fixed to a second lower vertical shaft (35). The gears (33) and (34) may have their combined ratio altered so that the rpm of the impeller drive shaft (41) can be changed as required. The shaft (35) passes through a single hole (36), (Seen more clearly in FIG. 7), in the modified stator blade (37), into the lower gear case (38). A bevel gear (39) fixed to the lower end of the shaft (35) meshes with a bevel gear (40) fixed to the impeller drive shaft (41).

[0022] In FIG. 3 is shown a mixed flow outboard jet pump being a dual shaft input configuration comprising an intake section (42), impeller housing (43), a single mixed flow impeller (44), stator-gearbox section (45), nozzle (46) and outboard powerhead (47). The drive train is otherwise identical to that shown in FIG. 1.

[0023] In FIG. 4 is shown a mixed flow outboard jet pump having a simpler drive train with fewer gears but in this instance also incorporating a trimming means that permits the nozzle (53) to be moved up and down relative to the intake section (48) and a grill cleaning system. Its main components are shown separated for clarity. The jet pump comprises an intake section (48), flexible sleeve (49), impeller housing (50), mixed flow impeller (51), stator-gearbox section (52), nozzle (53), and outboard powerhead (54). There is a single primary input shaft (55) used to transmit power to the stator-gearbox section (52). The shaft (55) passes through a single hole (56) in the modified stator blade (57), seen also in FIGS. 7, as (36) and (37), into the lower gearbox casing (58), the shaft (55) having a bevel gear (59) fixed to its lower end that meshes with the bevel gear (60) fixed to the impeller shaft (61).

[0024] Also shown in FIG. 4 a retractable grill cleaning system, seen also in FIG. 8, whereby a series of spaced grill bar fingers (62) are fixed by a hinge (63) at the upstream end of the fixed intake grill (64) that swing (65) down and between the fixed intake grill (64) from a recess (66) in the upper roof (67) of the intake section (48). A plunging rod (68) enables manual or remote activation of the bar fingers (62). This permits the removal of weeds and other debris from the intake grill (64). A drop-down intake grill cleaning system is currently in commercial use but in jet pumps with through-intake drive shafts the hinged grill is fixed to the underside of the fixed intake grill. When activated the hinged grill swivels down from between the fixed grill bars to below the keel line displacing any debris. In this arrangement however, the provision of the recess (66) places the bar fingers (62) outside of the intake flow path when not in use. Further the centred position of the rod (68) is permissible because there is no axial drive shaft present. In the isometric sectional view FIG. 5 is shown a more detailed view of the trimming means seen in FIG. 4. In FIG. 5 is the attachment means where the impeller housing (69), is mounted independently to the transom housing (70) via pivot pin (71) and a second pin (not visible) allowing the pumps output thrust to be transferred to the transom housing (70). A ram (72), seen also in FIG. 4, is fixed to the transom (73) and the upper gear case (74) seen in FIG. 4, thereby allowing remote control of up and down movement (75), FIG. 5, also seen FIG. 4 (65). The pivot pin (71) and its partner (not shown) are secured by insertion into the keyed slot(s) (76) and the retention fixture (77), locking plate (78) and bolts (79) and (80)