Propulsion device for a floating vessel

Abstract

 The invention relates to a propulsion device (1) for a floating vessel (2) such as a ship. The propulsion device (1) comprise a hub (3) to be rotated by a drive means (4) about an central axis of the hub (3), first blades (6) arranged at the hub (3) and extending radially outwards from the hub (3) so as to be rotated together with the hub (3) about the central axis, wherein each first blade (6) terminating in an outer tip (7), and an annular nozzle member (8) that at least partly surrounds the first blades (6) and that is arranged concentrically with the hub (3). The annular nozzle member (8) is attached to the outer tip (7) of at least one first blade (6) so as to be rotated together with the hub (3) and the first blades (6) about the central axis.

Description

Field of the invention

[0001] The invention relates to a propulsion device for a floating vessel such as a ship, said propulsion device comprising a hub to be rotated by a drive means about an central axis of the hub, first blades arranged at the hub and extending radially from the hub so as to be rotated together with the hub about the central axis of the hub, wherein each first blade terminating in an outer tip, and an annular nozzle member that surrounds the first blades and that is arranged concentrically with the hub as defined in the preamble of independent claim 1.

[0002] Two main types of propellers are used in propulsion devices: The first type is ducted propellers comprising a nozzle or Kort type shroud surrounding the propeller to increase thrust at low speeds. The second type is open propellers without a nozzle.

Objective of the invention

[0003] The obj ect of the invention is to provide a new and inventive propulsion device.

Short description of the invention

[0004] The propulsion device for a floating vessel of the invention is characterized by the definitions of independent claim 1.

[0005] Preferred embodiments of the propulsion device are defined in the dependent claims.

[0006] The invention is based on attaching the annular nozzle member to the outer tip of at least one first blade so as to be rotated together with the hub and the first blades about the central axis of the hub.

[0007] In a preferred embodiment of the invention the annular nozzle member is attached to the outer tip of each first blade.

[0008] In a preferred embodiment of the propulsion device the annular nozzle member has an inner surface having an inner diameter that increases in one direction of the central rotation axis and an outer surface having an outer diameter that increases in the same direction of the central rotation axis as the inner diameter of the inner surface increases in.

[0009] In a preferred embodiment of the invention the propulsion device comprises a pod housing for attachment to the floating vessel such as to a hull of a ship. In this preferred embodiment the propulsion device includes a shaft for the attachment of the propulsion device to the floating vessel and possible also a turning device for turning the pod housing with respect to the floating vessel for example for steering the floating vessel. In this preferred embodiment a propeller shaft extends from the inside of the pod housing so that the propeller shaft has a propeller shaft portion outside the pod housing. In this preferred embodiment the hub is attached to the propeller shaft portion outside the pod housing. In this preferred embodiment the annular nozzle member is arranged so that the inner diameter of the inner surface of the annular nozzle member increases in the direction away from the pod housing and so that the outer diameter of the outer surface of the annular nozzle member increases in the direction away from the pod housing. In this preferred embodiment the pod housing comprises drive means may include at least one of the following: an electrical motor within the pod housing for rotating the propeller shaft, or a gearing arrangement for rotating the propeller shaft with a motor arranged outside the pod housing such as within a hull of a ship.

[0010] An advantage with a propulsion device according to the invention is that the annular nozzle member increase thrust at low speeds (bollard pull thrust) with approximately 30% corresponding to open propeller (same thrust with lower energy consumption).

[0011] Another advantage with a propulsion device according to the invention is also reduced pressure pulses to vessel hull from propeller tips.

[0012] In a propulsion device according to the invention, because the annular nozzle member is fastened to the outer tip of at least one first blade so as to be rotated together with the hub and the first blades about the central axis of the hub, thrust and efficiency are increased.

[0013] Another advantage that is achieved with a propulsion device the according to the invention is that tip vortex cavitation is also reduced or eliminated.

[0014] Another advantage that is achieved with a propulsion device the according to the invention is that vessel hull vibration created by tip vortex cavitation is also reduced or eliminated.

[0015] Another advantage that is achieved with a propulsion device the according to the invention is that the construction is made strong by supporting outer tips of the first blades by the annular nozzle member.

[0016] First blade thickness may be reduced compared to an open propeller or to a propeller surrounded by an annular nozzle member that is not fastened to the propeller and by reducing first blade thickness to increase propeller efficiency further.

[0017] Because the annular nozzle member is fastened to the outer tip of at least one first blade so as to be rotated together with the hub and the first blades about the central axis of the hub also supports and protects first blade tips of ice impacts (ice breaking applications), grounding, wires/ropes etc.

[0018] By attaching annular nozzle member to at least one outer tip of at least one first blade so as to be rotated together with the hub and the first blades about the central axis of the hub, no separate nozzle supporting structures are needed as in conventional ducted propellers and due to that also reduce resistance created by such separate nozzle supporting structures are eliminated and costs are reduced. This also leads to simple product management; no need for special design when nozzle needed.

List of figures

[0019] In the following the invention will described in more detail by referring to the figures of which

Figure 1 shows a floating vessel in the form of a ship having a propulsion device according to an embodiment of the invention,

Figure 2 shows a propulsion device according to a first embodiment of the invention,

Figure 3 shows a propulsion device according to a second embodiment of the invention,

Figure 4 the embodiment shown in figure 3 as seen from one end,

Figure 5 shows a propulsion device according to a third embodiment of the invention,

Figure 6 shows a propulsion device according to a fourth embodiment of the invention,

Figure 7 the embodiment shown in figure 6 as seen from one end,

Figure 8 shows a propulsion device according to a fifth embodiment of the invention,

Figure 9 shows a propulsion device according to a sixth embodiment of the invention,

Figure 10 the embodiment shown in figure 9 as seen from one end, and

Figure 11 shows a propulsion device according to a seventh embodiment of the invention.

Detailed description of the invention

[0020] The invention relates to a propulsion device 1 for a floating vessel 2 such as a ship as shown in figure 1.

[0021] The propulsion device 1 comprises a hub 3 to be rotated by a drive means 4 about a central rotation axis A of the hub 3. The drive means 4 may for example be an electric motor or a combustion engine.

[0022] The hub 3 may comprise attachment means 5 for attaching the hub 3 to a propeller shaft 13 that is rotated by the drive means 4.

[0023] The propulsion device 1 comprises first blades 6 arranged at the hub 3 and extending radially from the hub 3 so as to be rotated together with the hub 3 about the central rotation axis A of the hub 3. Each first blade 6 terminates in an outer tip 7. The first blades 6 are preferable identical and evenly disposed with respect to the hub 3.

[0024] The propulsion device 1 comprises an annular nozzle member 8 that at least partly, preferably completely, surrounds the first blades 6 and that is arranged concentrically with the hub 3. The annular nozzle member 8 is attached to the outer tip 7 of at least one first blade 6 so as to be rotated together with the hub 3 and the first blades 6 about the central axis of the hub 3. The annular nozzle member 8 is preferably, but not necessarily, attached to the outer tip 7 of each first blade 6.

[0025] In a preferred embodiment of the propulsion device 1 the annular nozzle member 8 has an inner surface 9 having an inner diameter that increases in direction of the central rotation axis.

[0026] In a preferred embodiment of the propulsion device 1 the annular nozzle member 8 has an outer surface 10 having an outer diameter that increases in direction of the central rotation axis.

[0027] In a preferred embodiment of the propulsion device 1 the annular nozzle member 8 has an inner surface 9 having an inner diameter that increases in one direction of the central rotation axis and an outer surface 10 having an outer diameter that increases in the same direction of the central rotation axis as the inner diameter of the inner surface 9 increases in.

[0028] In a preferred embodiment of the propulsion device 1 the propulsion device 1 comprises a pod housing 11 for attachment to the floating vessel 2 such as to a hull of a ship. In this preferred embodiment the propulsion device 1 includes a shaft 12 for the attachment and possible also a turning device (not shown in the figures) for turning the pod housing 11 with respect to the floating vessel 2 for example for steering the floating vessel 2. In this preferred embodiment a propeller shaft 13 extends from the inside of the pod housing 11 so that the propeller shaft 13 has a propeller shaft portion 14 outside the pod housing 11. In this preferred embodiment the hub 3 is attached to the propeller shaft portion 14 outside the pod housing 11. In this preferred embodiment the annular nozzle member 8 is arranged so that the inner diameter of the inner surface 9 of the annular nozzle member 8 increases in the direction of the central rotation axis away from the pod housing 11 and so that the outer diameter of the outer surface 10 of the annular nozzle member 8 increases in the direction of the central rotation axis away from the pod housing 11. In this preferred embodiment the pod housing 11 comprises drive means 4 which may include at least one of the following: an electrical motor 15 within the pod housing 11 as shown in figures 5 8, and 11 for rotating the propeller shaft 13, or a gearing arrangement 16 as shown in figure 2 for rotating the propeller shaft 13 with a motor 17 arranged outside the pod housing 11 such as within a hull of a ship.

[0029] The annular nozzle member 8 may have a cross-section configuration in the direction of the central rotation axis of the hub 3 of a NACA (National Advisory Committee for Aeronautics) Airfoil type such of NACA type 4415 or be a Kort Nozzle of 19A or of 37 of the MARIN series.

[0030] In an embodiment of the propulsion device the first blades 6 are arranged in the axial direction of the central rotation axis of the hub in a first series 18 of first blades 6 and in a second series 19 of first blades 6. In this embodiment the first series 18 of first blades 6 are arranged in the axial direction of the central rotation axis of the hub at a different location than the second series 19 of first blades 6. In this embodiment the first blades 6 in the first series 18 of first blades 6 are identical and are evenly disposed with respect to the hub. In this embodiment the first blades 6 in the second series 19 of first blades 6 are identical and are evenly disposed with respect to the hub. The first blades 6 in the first series 18 of first blades 6 have preferably, but not necessarily, a smaller pitch than the first blades 6 in the second series 19 of first blades 6.

[0031] In the embodiment of the propulsion device shown in figures 6 to 8 the number of first blades 6 in the first series 18 of first blades 6 is the same as the number of first blades 6 in the second series 19 of first blades 6, and the first blades 6 in the second series 19 of first blades 6 are phase shifted with respect to the first blades 6 in the first series 18 of first blades 6 with an angle of a/2 about the central rotation axis of the hub, where

[0032] This means that if the number of first blades 6 in the first series 18 is 4 as is the situation in figures 6 to 8, a is 360/4 i.e. 90. In this case the first blades 6 in the second series 19 of first blades 6 are phase shifted with respect to the first blades 6 in the first series 18 of first blades 6 with an angle of 90/2, i.e. by 45 degrees.

[0033] In an embodiment of the propulsion device, such as in the embodiment shown in figures 9 to 11, second blades 20 are attached to the annular nozzle member 8 and extending radially inwards from the annular nozzle member 8 towards the central rotation axis of the hub so that each second blade has a free inner tip 21 that is unsupported by the hub. In this embodiment the second blades 20 are unsupported by the hub. In this embodiment of the propulsion device, the first blades 6 may be identical and be evenly disposed with respect to the hub, and the second blades 20 may be identical and may be evenly disposed with respect to the annular nozzle member.

[0034] In the embodiment of the propulsion device shown in figures 9 to 11, the first blades 6 and the second blades 20 are arranged in the axial direction of the central rotation axis of the hub in the same location. In the embodiment of the propulsion device shown in figures 8 and 9, the number of first blades 6 being the same as the number of second blades 20, and a space 22 is formed between two adjacent first blades 6, and a second blade is arranged in each space formed between two adjacent first blades 6.

[0035] In one preferred embodiment of the propulsion device 1 the hub 3, the first blades 6 and the annular nozzle member 8 is a one-piece part manufactured by casting. If the propulsion device 1 is provided with second blades 20, a such one-piece part may additionally comprise second blades 20.

[0036] In another preferred embodiment of the propulsion device 1 the annular nozzle member 8 is releasable attached to the outer tip 7 of at least one first blade 6 preferably so that the annular nozzle member 8 is releasably attached to the outer tip 7 of each first blade 6.

[0037] In another preferred embodiment of the propulsion device 1 at least one second blade is releasably attached to the annular nozzle member 8.

[0038] In still another preferred embodiment of the propulsion device 1 the annular nozzle member 8 is fixedly attached for example by welding to the outer tip 7 of at least one first blade 6 preferably so that the annular nozzle member 8 is fixedly attached to the outer tip of each first blade 6.

[0039] In another preferred embodiment of the propulsion device 1 at least one second blade is fixedly attached for example by welding to the annular nozzle member 8.

[0040] It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in various ways. The invention and its embodiments are therefore not restricted to the above examples, but they may vary within the scope of the claims.

Claims

1. A propulsion device (1) for a floating vessel (2) such as a ship, said propulsion device (1) comprising
a hub (3) to be rotated by a drive means (4) about an central axis of the hub (3),
first blades (6) arranged at the hub (3) and extending radially outwards from the hub (3) so as to be rotated together with the hub (3) about the central axis of the hub (3), wherein each first blade (6) terminating in an outer tip (7), and
an annular nozzle member (8) that at least partly surrounds the first blades (6) and that is arranged concentrically with the hub (3),
characterized
by the annular nozzle member (8) being attached to the outer tip (7) of at least one first blade (6) so as to be rotated together with the hub (3) and the first blades (6) about the central axis of the hub (3).

2. The propulsion device (1) according to claim 1, characterized by the annular nozzle member (8) being attached to the outer tip (7) of each first blade (6).

3. The propulsion device (1) according to claim 1 or 2, characterized by the first blades (6) being identical and being evenly disposed with respect to the hub (3).

4. The propulsion device (1) according to any of the claims 1 to 3, characterized by the annular nozzle member (8) having an inner surface (9) having an inner diameter that increases in one direction of the central axis of the hub (3).

5. The propulsion device (1) according to any of the claims 1 to 4, characterized by the annular nozzle member (8) having an outer surface (10) having an outer diameter that increases in one direction of the central axis of the hub (3).

6. The propulsion device (1) according to any of the claims 1 to 5, characterized
by the propulsion device (1) comprising a pod housing (11) and a shaft (12) for attaching the pod housing (11) to the floating vessel (2),
by a propeller shaft (13) extending from the pod housing (11) so that the propeller shaft (13) has a shaft portion (14) outside the pod housing (11),
by the hub (3) being attached to the shaft portion (14) outside the pod housing (11), and by the pod housing (11) comprises drive means (4) for rotating the hub (3) so that the first blades (6) attached to the hub (3) and the annular nozzle member (8) attached to the outer tip (7) of at least one first blade (6) rotates together with the hub (3) about the central axis of the hub (3).

7. The propulsion device (1) according to claim 6, characterized by the inner diameter of the inner surface (9) of the annular nozzle member (8) increases in the direction of the central axis of the hub (3) away from the pod housing (11).

8. The propulsion device (1) according to claim 6 or 7, characterized by the outer diameter of the outer surface (10) of the annular nozzle member (8) increases in the direction of the central axis of the hub (3) away from the pod housing (11).

10. The propulsion device (1) according to any of the claims 7 to 9, characterized by the pod housing (11) comprising drive means (4) including at least one of the following: an electrical motor (15) within the pod housing (11) for rotating the propeller shaft (13), or a gearing arrangement (16) for rotating the propeller shaft (13) with a motor (17) arranged outside the pod housing (11) such as within a hull of a ship.

11. The propulsion device (1) according to any of the claims 1 to 10, characterized
by the first blades (6) being arranged in the axial direction of the central rotation axis of the hub in a first series (18) of first blades (6) and in a second series (19) of first blades (6),
by the first series (18) of first blades (6) being arranged in the axial direction of the central rotation axis of the hub at a different location than the second series (19) of first blades (6),
by the first blades (6) in the first series (18) of first blades (6) being identical and being evenly disposed with respect to the hub, and
by the first blades (6) in the second series (19) of first blades (6) being identical and being evenly disposed with respect to the hub.

12. The propulsion device (1) according to claims 11, characterized
by the number of first blades (6) in the first series (18) of first blades (6) being the same as the number of first blades (6) in the second series (19) of first blades (6), and
by the first blades (6) in the second series (19) of first blades (6) being phase shifted with respect to the first blades (6) in the first series (18) of first blades (6) with an angle of a/2 about the central rotation axis of the hub, where

13. The propulsion device (1) according to any of the claims 1 to 10, characterized
by second blades (20) attached to the annular nozzle member (8) and extending radially inwards from the annular nozzle member (8) towards the central rotation axis of the hub so that each second blade has an free inner tip (21) that is unsupported by the hub (3), and
by the second blades (20) being unsupported by the hub.

14. The propulsion device (1) according to claim 13, characterized
by the first blades (6) being identical and being evenly disposed with respect to the hub, and
by the second blades (20) being identical and being evenly disposed with respect to the annular nozzle member.

15. The propulsion device (1) according to claim 13 or 14, characterized
by the first blades (6) and the second blades (20) being arranged in the axial direction of the central rotation axis of the hub in the same location,
by the number of first blades (6) being the same as the number of second blades (20), by a space being formed between two adjacent first blades (6), and
by a second blade being arranged in each space formed between two adjacent first blades (6).

Drawing