A mixed-flow water jet pump

Abstract

A mixed-flow water jet pump for propulsion vessels and other surface vessels. The jet pump may be a fixed assembly, or alternatively may partially include an entry section allowing for trimming functions and a flexible entry section extension, wherein the main input drive shaft does not pass through the entry section of the jet pump. The jet pump driver may include a dual-input drive shaft system or a single-input drive shaft system, wherein a dual-input drive system allows greater power to be delivered to the pump while maintaining reliability. The jet pump may have a stern drive or outboard configuration using an internal combustion engine or an electric motor as the primary drive unit.

Description

Technical Field

[0001] The present invention generally relates to a water jet propulsion device for propelling ships and other watercraft. Background Technology

[0002] Canadian Patent 2,698,429 (Davies) describes a waterjet propulsion pump that can be configured as an outboard driven configuration, wherein the outboard power head is externally fixed to the crossbeam of the seagoing vessel; alternatively, the propulsion pump can be configured as a stern drive unit, wherein the attachment of a bevel gear right-angle drive allows the drive engine to be mounted inside the seagoing vessel. Several previously patented machines have also been described, which were not commercially successful due to low efficiency and failure to meet basic functional problems such as trimming and maintainability. A previously patented outboard design, U.S. Patent 3,082,732 (Stallman), describes a centrifugal pump fixed to the power head, which remains commercially available. This jet pump meets many practical requirements demanded by customers but lacks the efficiency needed for broader application in large seagoing vessels. The device has steering and trimming capabilities and is mounted as an outboard configuration at the stern. Another outboard jet pump is described in U.S. Patent 5,769,674 (Stalman), but in this case, the jet pump has an axial flow configuration that is partially similar to the section inserted into the outer hull of the underhull. The problem with this device is that the upstream structure of the flow reduces its overall efficiency to a commercially unacceptable level, and therefore there is currently no market for it. A simple outboard jet pump design is shown in U.S. Patent 4,281,996 (Mouselet) with a gear section inside the flow path, where a vertical drive shaft penetrates to a drive gear downstream of the stator section. This patent fails to address the hydrodynamic requirements associated with this type of arrangement, and when in the tilted position, the inlet fixed to the main center section rotates away from the crossbeam along with the entire section. In this position, multiple directional changes are seen in the flow path, and when the boat is in planing mode, the nozzle is raised well above the water level, resulting in unnecessary head loss for the pump. A jet pump described in U.S. Patent 6,267,632B1 (Blanchard) possesses many features required by the market, but fails to address the major problem of pump efficiency, particularly regarding stator design, as seen in the aforementioned Canadian patent. U.S. Patent 6,776,674B2 (Blanchard) attempts to improve the efficiency of an outboard jet pump concept, but it is essentially a conventional axial-flow jet pump fixed to the ship's beam via a single rotary joint. This concept lacks the compactness of conventional outboard propeller systems that include trimming and steering functions. Furthermore, its main input drive shaft is located inside the flow path of the inlet section. Further improvements are described below, allowing for more reliable and higher power input than previously described, including a simplified trimming system. The use of a mixed-flow impeller is further described, which improves upon the pump due to more efficient recovery of radially induced energy and better control of the flow through the inlet section.This is achieved by calibrating the jet pump's capacity by adjusting the ratio of the impeller inlet area to its downstream outlet area. This provides a way to design the flow rate delivered from the inlet section that involves reducing the upstream diameter of the impeller, and thus also reducing the size or cross-sectional area of ​​the inlet section outlet itself. The reduced size of the inlet section, and therefore its encroachment on the inboard space, while simultaneously reducing the volume of water entrained during navigation on water, means that the impeller geometry (particularly regarding pitch) can be more advantageously configured to allow for greater variation in the pitch between the leading and trailing edges of the impeller, where the upstream diameter of the impeller is smaller than the upstream diameter at its downstream end. Mixed-flow design principles are currently employed by jet pump manufacturers, but in which the main input drive shaft is inserted axially through the inlet section. A single vertically arranged drive shaft through the stator section of the jet pump is shown in a Canadian patent, where the diameter of the jet pump is necessarily limited. This is partly due to the need to keep the stator blades (through which the shaft passes) as thin as possible while maintaining a hydrodynamically suitable geometry. This limitation therefore affects the hydrodynamics of the flow through the pump and the power or torque that can be safely applied to the shaft. To overcome these two problems, two vertically rotating input drive shafts interconnected by two meshing gears are shown, wherein both shafts pass through the same single stator vane. (e.g.) Figure 1 As shown, bevel gears are fixed to their lower ends. Therefore, each of the two input shafts receives approximately 50% of the power delivered by the drive engine, thus allowing for increased power input while maintaining the overall width of the stator blades without introducing additional hydrodynamic losses. The use of this dual-shaft improvement allows for even higher power input and thus can be used in larger vessels. For example, Figure 3 The jet pump seen in the image can be configured as an outboard unit attached to the stern of, for example, a commercial 30-meter planing boat that uses a gas turbine as its power source or a large electric motor. Figure 1 Regarding the jet pump seen, this demonstrates how pump efficiency can be improved by modifying the impeller housing and impeller to have a “mixed-flow” geometry, i.e., the impeller has a tapered periphery that mates with the geometry of the housing or impeller casing. In a further improvement, the impeller housing has two mounting pins positioned within two pivotable mounting points located in recesses in the two crossbeam walls. A third attachment is provided by a plunger fixed to the right-angle drive and crossbeam. A flexible sleeve connects the inlet section to the impeller housing, thus allowing the impeller housing / gearbox stator section assembly to rotate upwards and downwards independently of the inlet housing. The sleeve retains the removal of one of the clamps, slot locking plates, and plunger connections, allowing the entire impeller housing / gearbox stator section assembly and power head to be removed as a single unit for maintenance purposes. Figure 8The arrangement shown allows for an efficient trimming system but not the steering capability described in the aforementioned Canadian patent. Electric or hydraulic plungers fixed to the crossbeam, right-angle gearbox, or outboard leg housing can be remotely actuated, allowing the entire assembly to rotate independently of the entry section, thus aiding in the trimming of the sea vehicle. Thrust is directed towards the crossbeam rather than the entry, which obviously means that the entry can be constructed much lighter when it no longer receives thrust. The problem of debris being trapped in the entry grille is also solved by providing a simple, relatively lossless entry cleaning system in which the entry cleaning mechanism is positioned outside the entry flow path. The concept of an entry cleaning system is not new, and such systems are already in use in the market where cleaning rods are mounted to the entry grille itself. An example of an entry cleaning system is described in U.S. Patent 11,097,821B1 (Schultz), in which a set of interconnected grille cleaning rods can be lowered via fixed entry grille rods fixed to a Stallman outboard centrifugal jet pump. When not activated, the cleaning blades are positioned between the fixed blades, thus remaining within the main inlet flow, but also providing a solution for bar screen fouling. The difference in the current case is that the cleaning blades are located outside the inlet section flow, which is not satisfactorily achieved in jet pumps with axially positioned shafts or in the aforementioned example of a bar screen cleaning system for a Stallman centrifugal outboard jet pump. Summary of the Invention

[0003] This invention aims to further improve jet pump efficiency and allow for greater power input than described in the aforementioned Canadian patent, while maintaining the advantages of durability and ease of attachment to any sea vehicle. To provide the increased power input, a dual-input shaft system is described, in which the main drivetrain is divided into two, with the impeller shaft driven by two sets of bevel gears, each driven in the same direction. This maintains a right-angle drive and outboard configuration by allowing two vertical shafts to pass through a single improved stator blade without unduly increasing any hydrodynamic losses. In another variation, a dual-vertical-shaft solution is described, which reduces the capability for higher power input but allows for changing the impeller drive shaft speed by allowing the ratio of the two paired gears to be varied. This means that the main drive input gear ratio can be changed without altering the impeller drive shaft bevel gear ratio. Importantly, this feature thus allows for maximizing the gear size of the impeller drive shaft bevel gears without requiring, for example, smaller and less loaded bevel gears with fewer teeth. Regarding pump efficiency, the impeller and impeller housing also employ a mixed-flow geometry. This concept is not new, but given the absence of a main axial drive input shaft in the inlet section of the jet pump, it is possible to achieve greater effectiveness using a mixed-flow geometry. This is because the impeller's leading edge can extend to the very tip of the impeller hub. This capability allows for easier calibration of the incoming upstream flow by adjusting the impeller diameter and blade leading edge position with greater freedom. One of the main disadvantages of jet pumps compared to propeller drives, such as outboard propeller drives, is the risk of inlet section blockage. Traditionally, this problem has been partially overcome by inserting a fixed grill bar in the inlet section. This has proven ineffective in dealing with aquatic weeds, and many manufacturers have adopted drop-down through grill cleaning bar solutions, but these have limitations due to the presence of an axial shaft in the inlet section. In this invention, there is no axial shaft passing through the inlet section, thus allowing the installation of a drop-down cleaning screen with an actuating rod or plug centrally fixed to a swing grille that is free from drive shaft interference. In the retracted position, the grille bars or fingers are located inside separate recesses cast into the top of the entry section. This provides a relatively smooth surface because the bars are completely removed from the incoming flow.

[0004] In the machines described below, to simplify the description of each device, the nozzle steering and baffle-based reversing systems currently manufactured are excluded.

[0005] In summary, the following points are proposed:

[0006] (i) While maintaining pump efficiency, use a more robust drivetrain to increase the power input load capacity.

[0007] (ii) Improve pump efficiency and input flow rate by using mixed-flow geometry for the impeller and impeller housing.

[0008] (iii) The ability to change the impeller drive speed without changing the bevel gear.

[0009] (iv) Simplified trimming system.

[0010] (v) Provide an improved entry grille cleaning system. Attached Figure Description

[0011] The following is a description in the accompanying diagram:

[0012] Figure 1 An isometric sectional view of a mixed-flow stern-driven jet pump shows a right-angle drive, a single mixed-flow impeller, and a dual-shaft input configuration including a main input shaft, wherein input power is shared by an additional shaft via two meshing gears, and wherein the two shafts pass vertically through modified stator blades, as... Figure 6 As shown in the diagram. These two shafts, in turn, drive four interconnected bevel gears mounted inside the gearbox housing, whereby the impeller shafts rotate under their common input torque.

[0013] Figure 2 An isometric sectional view of a mixed-flow stern-driven jet pump shows a right-angle drive, a single mixed-flow impeller, and a gear train comprising a vertical input shaft with a gear fixed to its lower end; this gear meshes with a second gear, allowing for a change in gear ratio if desired, the second gear being fixed to a second adjacent vertical shaft extending vertically downward through modified stator blades, as shown. Figure 7 As shown, a bevel gear is fixed to the lower end of a vertical shaft, and this bevel gear meshes with a second bevel gear fixed to an impeller drive shaft.

[0014] Figure 3 Side view of a mixed-flow outboard jet pump, which has a single mixed-flow impeller, a dual-shaft input configuration including a main input shaft, wherein input power is shared by additional shafts via two meshing gears, and wherein the two shafts pass vertically through... Figure 6 The improved stator blades are shown. These two shafts, in turn, drive four interconnected bevel gears mounted inside the gearbox housing, whereby the impeller shafts rotate under their common input torque. A method of hinged jet pump in a vertical plane is also shown, allowing the impeller housing / gearbox stator section assembly to rotate up and down, thereby allowing the vehicle to be trimmed in taxiing mode.

[0015] Figure 4Side view of a mixed-flow outboard jet pump with a single mixed-flow impeller, showing the separated main components. An inlet including a pivoting bar screen cleaning device is also shown. This device includes rods that descend between the fixed inlet section bar screens but retract into a recess located at the upstream top of the inlet section to minimize hydrodynamic losses.

[0016] Figure 5 An isometric sectional view of the jet pump shows the mixed-flow impeller housing, the inlet section, and the pivoting arrangement that allows the impeller housing / gearbox stator section to rotate up and down independently of the inlet section.

[0017] Figure 6 : Cross-sectional isometric view of the jet pump stator, showing the improved stator blades and two vertical holes that allow two vertical input drive shafts to pass through and enter the lower gearbox.

[0018] Figure 7 Isometric cross-sectional view of the jet pump stator, showing an improved stator blade with a vertical bore that allows a vertical input shaft to pass through and enter the lower gearbox.

[0019] Figure 8 : A view of the jet pump entering the section and the entry grille, showing the device for removing debris from between the fixed entry grille bars. Detailed Implementation

[0020] exist Figure 1 A mixed-flow jet pump is shown, having an inlet section 1, the downstream end of which is directly fixed to a conical impeller housing 2. A stator gearbox section 3, a right-angle drive 4 fixed to the upper part of the stator gearbox section 3, and a nozzle 5 are also fixed to the impeller housing 2. A mixed-flow impeller 6 located inside the impeller housing 2 is shown. The jet pump has a main input drive shaft 7, which is connected to a vertical drive shaft 8 via bevel gears 9 and 10. The vertical shaft 8 is connected to a lower vertical shaft 11 via a mating spline (not shown), wherein a gear 12 is fixed to the lower vertical shaft 11, which meshes with a gear 13 fixed to a lower vertical shaft 14. Both vertical shafts 11 and 14 pass through holes 15 and 16 shown in the modified stator blades 17 (in... Figure 6 (More clearly visible). Shafts 11 and 14 have bevel gears 18 and 19 fixed at their lower ends, which mesh with bevel gears 20 and 21. Gears 20 and 21 are fixed to the impeller shaft 22, and together drive these gears to rotate shaft 22 in the same direction. Therefore, this gear system allows an increased power input level to be applied to the jet pump.

[0021] exist Figure 2A similar jet pump is shown, featuring a top-mounted right-angle drive input 23, but with a different gear arrangement. This mixed-flow jet pump has an inlet section 24, the downstream end of which is directly fixed to a conical impeller housing 25. A stator gearbox section 26 and the right-angle drive input 23, fixed to the upper part of the stator gearbox section 26, are also fixed to the impeller housing 25. A mixed-flow impeller 27 is shown inside the impeller housing 25. The jet pump has a main input drive shaft 28 connected to a vertical drive shaft 29 via bevel gears 30 and 31. The vertical shaft 29 is connected to a shortened lower vertical shaft 32 via a mating spline (not shown), wherein a gear 33 is fixed to the lower vertical shaft 32, meshing with a gear 34 fixed to a second lower vertical shaft 35. Gears 33 and 34 allow for a change in their combination ratio, enabling the rotational speed (rpm) of the impeller drive shaft 41 to be varied as needed. Shaft 35 passes through a single hole 36 in the improved stator blade 37 (in Figure 7 (More clearly visible in the middle) enters the lower gearbox 38. The bevel gear 39, fixed to the lower end of the shaft 35, meshes with the bevel gear 40, fixed to the impeller drive shaft 41.

[0022] exist Figure 3 The image shows a mixed-flow outboard jet pump in a dual-shaft input configuration, which includes an inlet section 42, an impeller housing 43, a single mixed-flow impeller 44, a stator gearbox section 45, a nozzle 46, and an outboard power head 47. The drivetrain is otherwise similar to... Figure 1 The transmission system shown is the same.

[0023] exist Figure 4 The image shows a mixed-flow outboard jet pump with a simpler drivetrain containing fewer gears, but in this case, also including a grille cleaning system and a trimming device that allows the nozzle 53 to move up and down relative to the inlet section 48. For clarity, its main components are shown separately. The jet pump includes the inlet 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 present for transmitting power to the stator gearbox section 52. The shaft 55 passes through a single hole 56 in the modified stator blades 57 (also...). Figure 7 As can be seen in Figures 36 and 37), the gearbox 58 is connected to the lower gearbox 58. A bevel gear 59 is fixed at the lower end of the shaft 55, which meshes with a bevel gear 60 fixed to the impeller shaft 61.

[0024] exist Figure 4 The image also shows a retractable grille cleaning system (also shown in...) Figure 8As can be seen in the diagram, a series of spaced-apart bar-shaped fingers 62 are secured to the upstream end of a fixed entry bar 64 by hinges 63. These bar-shaped fingers swing downwards 65 from recesses 66 in the upper top 67 of the entry section 48 between the fixed entry bars 64. Insert rods 68 enable manual or remote activation of these bar-shaped fingers 62. This allows for the removal of weeds and other debris from the entry bar 64. Pull-down entry bar cleaning systems are currently commercially available, but in jet pumps with a through-type entry drive shaft, the articulated bar is fixed to the underside of the fixed entry bar. When activated, the articulated bar rotates downwards from between the fixed bar bars to below the keel line to remove any debris. However, in this arrangement, the recesses 66 allow these bar-shaped fingers 62 to be positioned outside the entry flow path when not in use. Furthermore, the centered position of the rods 68 is permissible because there is no axial drive shaft. Figure 5 It is shown in the equidistant cross-sectional view Figure 4 A more detailed view of the trimming device shown. Figure 5 This refers to the attachment method of the impeller housing 69, which is independently mounted to the beam housing 70 via a pivot pin 71 and a second pin (not visible), thereby allowing the pump output thrust to be transmitted to the beam housing 70. The plunger 72 (also...) Figure 4 (See image) Fixed to crossbeam 73 and upper gearbox 74 ( Figure 4 (As can be seen in the image), thus allowing remote control to move it up and down by 75 ( Figure 5 , also Figure 4 (See image). The pivot pin 71 and its mating parts (not shown) are secured by insertion into the key slot 76 and retaining clamp 77, locking plate 78 and bolts 79 and 80.

Claims

1. A mixed-flow water jet pump, the mixed-flow water jet pump comprising an inlet section, a mixed-flow impeller housing, a mixed-flow impeller, a stator gearbox section, a right-angle gearbox, and a nozzle fixed to the stator gearbox section, wherein the right-angle gearbox and the stator gearbox section have a gear train, wherein the gear train includes a main input shaft connected to a vertical input shaft via two meshing bevel gears, the vertical input shaft being connected to a lower shaft via a mating spline, a gear fixed to the upper end of the lower shaft, the gear meshing with a gear fixed to the upper end of an adjacent vertical lower shaft, and wherein... The two lower shafts enter the lower gearbox through two holes in a single hydrodynamically modified stator blade. The lower end of the lower shaft is fixed with a bevel gear, which meshes with two other bevel gears fixed to the impeller drive shaft. The two lower shafts transmit equal power or torque to the impeller drive shaft. The entry section, the mixed-flow impeller housing, the stator gearbox section, the nozzle, and the right-angle gearbox are fixed to each other.

2. A mixed-flow water jet pump, the mixed-flow water jet pump comprising an inlet section, a mixed-flow impeller housing, a mixed-flow impeller, a stator gearbox section, a right-angle gearbox, and a nozzle fixed to the stator gearbox section, wherein the right-angle gearbox and the stator gearbox section have a gear train, wherein the gear train includes a main input shaft connected to a vertical input shaft via two meshing bevel gears, the vertical input shaft being connected to a lower shaft via a mating spline, a gear fixed at the upper end of the lower shaft, the gear meshing with a gear fixed to the upper end of an adjacent vertical lower shaft, the gear being replaceable by gears with different transmission ratios, the adjacent vertical lower shaft entering the lower gearbox through a single hole in a hydrodynamically improved stator blade, a bevel gear fixed at the lower end of the adjacent vertical lower shaft, the bevel gear meshing with a bevel gear fixed to an impeller shaft, the inlet section, the mixed-flow impeller housing, the stator gearbox section, the nozzle, and the right-angle gearbox being fixed to each other.

3. A mixed-flow water jet pump, the mixed-flow water jet pump comprising an inlet section, a mixed-flow impeller housing, a mixed-flow impeller, a stator gearbox section, a nozzle fixed to the stator gearbox section, and an outboard power head fixed to the stator gearbox section, the stator gearbox section having a gear train, wherein the gear train includes a vertical input shaft connected to the outboard power head, the vertical input shaft being connected to a lower shaft via a spline connection, a gear fixed to the upper end of the lower shaft, the gear meshing with a gear fixed to the upper end of an adjacent vertical lower shaft, and wherein... The two lower shafts enter the lower gearbox through two holes in a single hydrodynamically modified stator blade. The lower end of the lower shaft is fixed with a bevel gear, which meshes with two other bevel gears fixed to the impeller drive shaft. The two lower shafts transmit equal power or torque to the impeller drive shaft. The entry section, the mixed-flow impeller housing, the stator gearbox section, the nozzle, and the outboard power head are fixed to each other.

4. A mixed-flow water jet pump, comprising an inlet section, a mixed-flow impeller housing, a mixed-flow impeller, a flexible sleeve fixed to the inlet section and the mixed-flow impeller housing, a stator gearbox section, a nozzle fixed to the stator gearbox section, and an outboard power head fixed to the stator gearbox section, the outboard power head being connected to the stator gearbox section via a vertical input drive shaft, the vertical input drive shaft being connected to a gear train via a spline, the gear train including a vertical lower shaft, a gear fixed to the upper end of the vertical lower shaft, the gear meshing with a gear fixed to the upper end of an adjacent vertical lower shaft, and wherein... The two lower shafts enter the lower gearbox through two holes in the hydrodynamically modified stator blades. A bevel gear is fixed to the lower end of each lower shaft, which meshes with two other bevel gears fixed to the impeller drive shaft. The two lower shafts transmit equal power or torque to the impeller drive shaft. The mixed-flow impeller housing is connected to the crossbeam of the sea vehicle via two pivot pins and a plunger. The mixed-flow impeller housing is fixed to the stator gearbox section at its downstream end. Thus, the outboard power head, the stator gearbox section, and the mixed-flow impeller housing are connected to the entry section via the flexible sleeve, the pivot pins, and the plunger, allowing for vertical rotation for trimming purposes.

5. A mixed-flow water jet pump, comprising an inlet section, a mixed-flow impeller housing, a mixed-flow impeller, a flexible sleeve attached to the inlet section and the mixed-flow impeller housing, a stator gearbox section, a right-angle gearbox, a nozzle fixed to the stator gearbox section, and a gear train, the gear train comprising a main input shaft connected to a vertical input shaft via two meshing bevel gears, the vertical input shaft being connected to a lower shaft via a mating spline, a gear fixed to the upper end of the lower shaft, the gear meshing with a gear fixed to the upper end of an adjacent vertical lower shaft, and wherein... The two lower shafts enter the lower gearbox through two holes in a single hydrodynamically modified stator blade. A bevel gear is fixed to the lower end of each lower shaft, which meshes with two additional bevel gears fixed to the impeller drive shaft. The two lower shafts transmit equal power or torque to the impeller drive shaft. The mixed-flow impeller housing is connected to the crossbeam of the watercraft via two pivot pins and a plunger. The right-angle gearbox, the stator gearbox section, and the mixed-flow impeller housing are connected to the entry section via a flexible sleeve, the pivot pins, and the plunger, allowing for vertical rotation for dressing purposes.

6. A mixed-flow water jet pump, comprising an inlet section, a mixed-flow impeller housing, a mixed-flow impeller, a flexible sleeve attached to the inlet section and the mixed-flow impeller housing, a stator gearbox section, a nozzle fixed to the stator gearbox section, and an outboard power head fixed to the stator gearbox section, the outboard power head being connected to the stator gearbox section via a main vertical input shaft, the main vertical input shaft being connected via a mating spline to a gear train including a vertical lower shaft, the vertical lower shaft entering a lower gearbox through a single hole in a hydrodynamically modified stator blade, a bevel gear fixed to the end of the vertical lower shaft, the bevel gear meshing with a bevel gear fixed to an impeller drive shaft, the impeller housing being connected to the crossbeam of a sea vehicle via two pivot pins and a plunger, and wherein... The outboard power head, the stator gearbox section, and the mixed-flow impeller housing are connected to the entry section via the flexible sleeve, the pivot pin, and the plunger, and can rotate up and down to achieve the purpose of trimming.

7. The mixed-flow water jet pump according to any one of claims 1 to 6, wherein, The entry section may include an articulated pivot bar screen cleaning device, which is retracted into a recess at the top of the entry section of the water jet pump.

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