DE20119724U1 - Lateral thruster, in particular bow thruster, for ships - Google Patents

Description

RICHTER, WERDERMANN &

EUROPEAN PATENT ATTORNEYS ⁰ PATENT ATTORNEYS

EUROPEAN TRADEMARK ATTORNEYS

HAMBURG BERLIN MUNICH

DIPL.-ING. JOACHIM RICHTER ⁰ DIPL.-ING. HANNES GERBAULET ⁰ DIPL.-ING. FRANZ WERDERMANN" DIPL.-GEOL. MATTHIAS RICHTER

New Wall 10

20354 HAMBURG

&bgr; (040) 34 00 45 / 34 00 56

Fax (040) 35 2415

Email: Richter@pat-Richter.de

BERLIN

HAMBURG

MUNICH

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J 01340 III 2724

HAMBURG

0 4 DEC 2001

Applicant:

Jastram GmbH & Co. KG Billwerder Billdeich 603 D-21033 Hamburg (DE)

Title:

Transverse thrusters, in particular bow thrusters, for ships

The invention relates to a transverse thruster, in particular a bow thruster, for ships according to the preamble of claims 1 to 4.

Such transverse thrusters are well known. In these, a propeller rotates in a channel mounted transversely in the bow and/or stern and pushes the water sucked in, working similarly to an axial pump, to starboard or port, depending on the selected direction of rotation or the blade position in the case of variable pitch propellers. With such a transverse thrust system,

This also makes it easier to maneuver a ship at low speeds.

When transverse thrusters are working, unpleasant noises are usually generated, which are particularly annoying in the living and recreation areas on ships. These noises are caused by the gear teeth working and by water noises coming from the propeller. Furthermore, the screws, which are usually subject to high loads, produce cavitations, i.e. steam bubbles, due to negative pressure. When these steam bubbles suddenly condense, hammer-like blows are created, which are unpleasantly noticeable via the tunnel wall into the interior of the ship as structure-borne noise and through the water as water noise. In the living areas and recreation areas, the ambient noise is then sometimes unbearable for the crew and passengers.

DE-B-2 644 844 discloses a method and a device for introducing gas and water into the propeller area of a jet rudder. This method consists in injecting gas, e.g. air, and water in a uniform mixture as a directed jet. By injecting an air/water mixture in the form of a jet into the propeller area, the noise reduction is to be improved largely independently of the associated reduction in performance. However, the problem of dampening the hammer-like blows that occur during the sudden condensation of the cavitation bubbles is not solved with this method, because the water flowing into the propeller area with the air according to this method does not lead to the elimination or dampening of the pressure and sound waves that occur during the condensation of the cavitation bubbles, because an air/water mixture does not create a sufficiently soft cushion in the water, which in its function as an absorption body absorbs the hammer-like blows caused by the propeller by the generation of cavitation bubbles, so that

the hammer-like blows and the associated sound waves resulting from the sudden condensation of cavitation bubbles are not sufficiently insulated or absorbed.

For sound insulation of transverse thruster control systems, it is known from WO 84/03078 to create separate gas-filled cavities in a water-filled space in the double-walled tunnel housing in which the propeller is arranged.

Another arrangement for sound insulation is disclosed in DE-A-2 803 336, which relates to an arrangement for sound insulation of transverse thruster steering systems for ships, in which the tunnel tube containing the propeller is arranged in a transverse tube, forming an annular space, which is located in the hull transverse to its longitudinal axis. The wall of the tunnel tube is supported on the wall of the transverse tube with elastic molded bodies interposed. Such an arrangement dampens the sound waves emanating from the tunnel tube, but the noise emanating from the gear or the drive of the propeller is not reduced by such an elastic suspension of the tunnel tube, since there is no direct elastic suspension of the gear housing. FR-A-2 252 949 provides for the introduction of compressed air into the jacket area of jacketed propellers in order to prevent cavitation erosion, but the formation of an annular compressed air supply area in the area of the openings on both sides of the jacket tube is not provided for, so that no cushion of air and water can be formed to absorb the hammer-like blows resulting from the condensation of cavitation bubbles.

EP 0 306 642 Bt discloses a transverse thruster, in particular a bow thruster, for ships, which consists of a transverse thrust channel formed in the ship's hull and consisting of a tunnel tube,

in which a gear housing with a propeller is arranged, wherein outlet openings for introducing a medium under pressure into the propeller area are formed in or on the wall of the tunnel tube. The outlet openings are connected via at least one supply pipe to a compressed air generation device for supplying compressed air with the exclusion of water in the propeller area and for forming a soft cushion consisting of air and water to absorb the hammer-like blows generated by the cavitation bubbles obtained by the condensation, wherein the tunnel tube has an annular air supply pipe on its outer wall surface adjacent to its two lateral openings. Each air supply pipe provided with air supply nozzles has air outlet openings arranged in the area of the wall or in the interior of the tunnel tube, wherein the two annular air supply pipes are connected to one another via an air connection line. One of the two annular air supply pipes is connected to the compressed air generation device.

It is also known to provide the side openings of the tunnel tube with ring grilles.

It is the object of the present invention to achieve a reduction in the hammer-like impacts caused by the sudden condensation of cavitation bubbles and transmitted via the tunnel wall into the ship's interior as structure-borne noise, and the mechanical noises emanating from the propeller gear in transverse thrust ducts of transverse thrusters according to the type described at the outset, in order to avoid the unpleasant noises that occur when transverse thrusters are in operation.

This object is achieved in a transverse thruster according to the type described above by the features characterized in claims 1 to 4.

According to the invention, in a transverse thruster according to the type described at the outset, in all embodiments of claims 1 to 4, ring grids closing these openings are arranged in the region of the two lateral openings of the tunnel tube.

According to claim 2, in addition to this ring grid arrangement, the invention provides that at least the two outer ring bodies of the two ring grids have guide plates in their lower regions which are directed forwards or towards the bow or whose front guide plate sections have a position directed downwards in the direction of the lateral openings and inclined or directed forwards.

The transverse thruster according to claim 3 also has ring grids, but each ring grid comprises a number of tubular ring bodies which have a number of air outlet nozzles distributed over each ring body, all ring bodies being connected to a compressed air generating device via an air supply line.

A further inventive embodiment according to claim 4 provides, in addition to the ring grille arrangement, that at least the two outer ring bodies of the two ring grilles have guide plates in their lower regions which are directed forwards or towards the bow or whose front guide plate sections have a downwards in the direction of the lateral openings and inclined or forwards position, and that each ring grille comprises a number of tubular ring bodies which have a number of air outlet nozzles distributed over each ring body, wherein all ring bodies have a

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Air supply line connected to a compressed air generating device.

According to the invention, in a transverse thruster of the type described at the outset, the ring bodies of each ring grid are tubular, the ring bodies having a number of air outlet nozzles distributed over each ring body. All ring bodies are connected to a compressed air generating device via an air supply line.

Each ring grid has any number of ring bodies, preferably two ring bodies with air outlet nozzles, which are arranged on the ring body in such a way that air jets emerge from the air outlet nozzles.

This inventive design has the advantage that air is supplied to the sucked-in water in the entrance area of the tunnel tube, specifically on the suction side, i.e. the air injection area is thus moved to the area of the side openings of the tunnel tube. The mixing of the sucked-in water with the fine air bubbles thus takes place in the area of the side openings of the tunnel tube, specifically where experience has shown that the turbulence is very high, so that a high degree of mixing is achieved in this area. A transverse thruster design according to the invention of this type is most effective in such structural designs. A good mixing of air and water is achieved in the entire area even before the propeller, which at the same time contributes to optimizing noise reduction without any loss of performance due to the many small air bubbles generated.

Further advantageous embodiments of the invention are the subject of the subclaims.

In order to support the flow of water into the tunnel pipe on the suction side, a further embodiment of the invention provides that the two outer ring bodies of the two ring grids have guide plates in their lower areas with a downward and inclined position in the direction of the side openings of the tunnel pipe. The forward inclination of the guide plates on the two outer ring bodies of each ring grid is such that the flow surfaces of the guide plates for the sucked-in water are at an angle, including approximately at a right angle, to the inclination of the ship's hull side walls.

The alignment of the guide vanes depends on the local conditions and does not always have to be at right angles to the outer skin. The guide vanes can also be inclined towards the bow of the ship. This is particularly important if the bow thruster is also to be effective when the ship is underway, as the inflow situation at the inlet at the front edge of the pipe generally worsens when the ship is underway.

According to the invention, a particularly advantageous embodiment is one in which an annular air supply pipe with air outlet nozzles is arranged in the area of the side openings of the tunnel pipe, specifically in the transition area between the wall of the tunnel pipe and the side wall of the ship's hull, whereby the air supply pipe is connected to the compressed air generation device and is arranged in the inclined plane formed by the ship's side wall in the area of the side opening of the tunnel pipe. Due to this embodiment, air is already supplied to the water in the inflow area to the tunnel pipe, so that in an area in front of the side opening of the tunnel pipe, a good mixing of air and water is already achieved.

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The arrangement of the nozzles is left to the structural conditions. In another structural design, the air supply pipe is also the connecting pipe at the seam between the bow thruster tunnel and the ship's outer skin. A pipe is often inserted here because this makes it very easy and economical to create a connection.

Embodiments of the invention are explained in more detail below with reference to the drawings.

Fig. 1 a vertical section through a tunnel tube with the

Ring grilles with air outlet nozzles arranged at the side of the tunnel tube openings,

Fig. 2 an enlarged vertical section through the tunnel tube in the area of its side opening with a ring grille arranged in it, with guide plates and ring-shaped air supply pipes,

Fig. 2A is an enlarged vertical section of the seam between the bow thruster tunnel and the ship's outer skin with the air supply pipe arranged in the seam area,

Fig. 3 an enlarged front view of a ring grille with air outlet nozzles,

Fig. 4 an enlarged front view of a ring grid and

Fig. 5 is an enlarged vertical section through the tunnel tube in the area of its side openings with ring grids carrying guide plates arranged therein.

In the embodiment of a ship's transverse thruster 20 shown in Fig. 1, the hull of a ship with its side walls 11, 12 is indicated by 10. The transverse thruster is arranged in the hull 10 and is formed by a tunnel tube 30, the wall of which is designated by 31. The side openings of the tunnel tube 30 are designated by 30a, 30b.

In the interior 30c of the tunnel tube 30, a gear housing 24 with a propeller nacelle 26 is arranged, which has a propeller 25. The gear housing 24 with the propeller 25 is suspended in a tube-like extension 23 which is formed on the tunnel tube 30.

Ring grilles 40, 40' are arranged in the two lateral openings 30a, 30b of the tunnel tube 30 (Fig. 1, 4 and 5). The two ring grilles 40, 40' are of identical design. The ring grilles 40, 40' according to Fig. 4 and 5 do not have any air outlet nozzles, whereas the ring grilles 40, 40' of Fig. 1, 2, 2A and 3 are provided with air outlet nozzles 43 and 63 respectively. Each ring grille 40, 40' comprises a number of tubular ring bodies 41, 42 which have a number of air outlet nozzles 43 distributed over each ring body, with all ring bodies 41, 42 being connected to a compressed air generating device 45 via an air supply line 44. The number of ring bodies of each ring grid 40, 40' can be chosen arbitrarily; it depends on the size of the side openings 30a, 30b of the tunnel tube. Ring grids 40, 40' are preferably used with two ring bodies 41, 42, as shown in Fig. 2 and 3, with the ring body 41 forming the outer ring body and the ring body 42 forming the inner ring body of the two ring bodies. The air outlet nozzles 43 of the ring bodies 41, 42 are arranged in such a way that air jets exit from the air outlet nozzles into the water.

As shown in Fig. 1 and 2, the two ring grids 40, 40' are arranged in the side openings 30a, 30b of the tunnel tube 30 in accordance with the inclination of the side walls 11, 12 of the hull 10, so that the individual ring bodies 41, 42 are offset from one another, which means that air can be blown unhindered into the sucked-in water via the air outlet nozzles 43 from the ring bodies 41, 42.

In the inflow area of the side openings 30a, 30b of the tunnel tube 30 or the ring grids 40, 40', the two outer ring bodies 41, 42 of the two ring grids 40, 40' have guide plates 50 in their lower areas with an inclined position directed downwards and, if necessary, forwards in the direction of the side openings 30a, 30b of the tunnel tube 30, as shown in Fig. 2, 4 and 5. The slightly inclined front sections of the guide plates are designated 50a. The guide plates themselves are arranged parallel to the longitudinal axis of the tunnel tube 30, whereas the front guide plate sections 50a are designed to be slightly inclined downwards. The forward-facing inclination of the guide plates 50 on the two outer ring bodies 41, 42 of each ring grid 40, 40' can be such that the inflow surfaces of the guide plates 50 for the sucked-in water are approximately at a right angle to the inclination of the hull side walls 11, 12, but other angular positions are also possible.

In order to achieve air injection in front of the side openings 30a, 30b of the tunnel tube 30 or in the immediate area of these two side openings 30a, 30b, as can be seen from Fig. 2, an annular air supply pipe 60 with inwardly directed air outlet nozzles 63 is arranged in the area of each side opening 30a, 30b of the tunnel tube 30, namely in the transition area between the wall 31 of the tunnel tube 30 and the side wall 11 or 12 of the hull 10, wherein the air supply pipe 60 is also connected to the compressed air generation device 45. The arrangement of the annular air supply pipe 60 in the region of each lateral opening 30a, 30b of the tunnel pipe 30 is such that the surface formed by the air supply pipe 60 is inclined and lies in the inclined plane formed by the ship's side wall 11 or 12 in the region of the lateral opening of the tunnel pipe.

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Fig. 2A shows a structural design in which the air supply pipe 60 simultaneously forms the connecting pipe at the seam between the bow thruster tunnel 30 or the tunnel side wall and the side wall 11 or 12 of the hull 10 or the ship's outer skin, wherein the air supply pipe 60, as shown, is mounted with a _projection 60a from the plane of the ship's outer skin or the hull side wall 11 and a projection 60b from the plane of the side wall of the tunnel pipe 30.

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Claims (9)

1. Transverse thruster, in particular bow thruster, for ships, consisting of a transverse thrust channel formed in the hull ( 10 ) and consisting of a tunnel tube ( 30 ) in which a gear housing ( 24 ) with a propeller ( 25 ) is arranged, characterized in that in the region of the two lateral openings ( 30 a, 30 b) of the tunnel tube ( 30 ) ring grilles ( 40 , 40 ') closing these openings are arranged. 2. Transverse thruster, in particular bow thruster, for ships, consisting of a transverse thrust channel formed in the hull ( 10 ) and consisting of a tunnel tube ( 30 ), in which a gear housing ( 24 ) with a propeller ( 25 ) is arranged, characterized in that in the region of the two lateral openings ( 30 a, 30 b) of the tunnel tube ( 30 ) ring grilles ( 40 , 40 ') closing these openings are arranged, wherein at least the two outer ring bodies ( 41 , 42 ) of the two ring grilles ( 40 , 40 ') have guide plates ( 50 ) in their lower regions which are directed forwards or towards the bow or whose front guide plate sections ( 50 a) have a position directed downwards in the direction of the lateral openings ( 30 a, 30 b) and inclined or directed forwards. 3. Transverse thruster, in particular bow thruster, for ships, consisting of a transverse thrust channel formed in the hull ( 10 ) and consisting of a tunnel tube ( 30 ), in which a gear housing ( 24 ) with a propeller ( 25 ) is arranged, characterized in that in the region of the two lateral openings ( 30 a, 30 b) of the tunnel tube ( 30 ) ring grilles ( 40 , 40 ') closing these openings are arranged, each ring grille ( 40 , 40 ') comprising a number of tubular ring bodies ( 41 , 42 ) which have a number of air outlet nozzles ( 43 ) distributed over each ring body, all ring bodies ( 41 , 42 ) being connected to a compressed air generating device ( 45 ) via an air supply line ( 44 ). 4. Transverse thruster, in particular bow thruster, for ships, consisting of a transverse thrust channel formed in the hull ( 10 ) and consisting of a tunnel tube ( 30 ), in which a gear housing ( 24 ) with a propeller ( 25 ) is arranged, characterized in that in the area of the two lateral openings ( 30 a, 30 b) of the tunnel tube ( 30 ) ring grilles ( 40 , 40 ') are arranged which close these openings, that at least the two outer ring bodies ( 41 , 42 ) of the two ring grilles ( 40 , 40 ') have guide plates ( 50 ) in their lower areas which are directed forwards or towards the bow or whose front guide plate sections ( 50 a) have a downwards in the direction of the lateral openings ( 30 a, 30 b) and are inclined or directed forwards, and that each ring grid ( 40 , 40 ') comprises a number of tubular ring bodies ( 41 , 42 ) having a number of air outlet nozzles ( 43 ) distributed over each ring body, wherein all ring bodies ( 41 , 42 ) are connected to a compressed air generating device ( 45 ) via an air supply line ( 44 ). 5. A transverse thruster according to one of claims 3 and 4, characterized in that each ring grid ( 40 , 40 ') has any number of ring bodies, preferably two ring bodies ( 41 , 42 ), with air outlet nozzles ( 43 ) which are arranged on the ring bodies ( 41 , 42 ) in such a way that air jets emerge from the air outlet nozzles ( 43 ) and air is blown into the sucked-in water. 6. Transverse thruster according to one of claims 1 to 5, characterized in that the ring grids ( 40 , 40 ') are arranged in the lateral openings ( 30a , 30b ) of the tunnel tube ( 30 ) according to the inclination of the side walls ( 11 , 12 ) of the hull ( 10 ), so that the individual ring bodies ( 41 , 42 ) are offset from one another. 7. Transverse thruster according to one of claims 2 or 4, characterized in that the guide plate sections ( 50a ) of the guide plates ( 50 ) on the two outer ring bodies ( 41 , 42 ) of each ring grid ( 40 , 40 ') which have a forward-directed inclination are such that the inflow surfaces of the guide plates ( 50 ) for the sucked-in water are at an angle or approximately at a right angle to the inclination of the side walls ( 11 , 12 ) of the hull ( 10 ). 8. Transverse thruster according to one of claims 1 to 7, characterized in that in the region of the lateral openings ( 30 a, 30 b) of the tunnel tube ( 30 ), specifically in the transition region between the wall ( 31 ) of the tunnel tube ( 30 ) and the side wall ( 11 , 12 ) of the hull ( 10 ), an annular air supply pipe ( 60 ) with air outlet nozzles ( 63 ) is arranged, wherein the annular air supply pipe ( 60 ) is connected to the compressed air generating device ( 45 ) and is arranged in the oblique plane formed by the side wall ( 11 , 12 ) of the hull ( 10 ) in the region of the lateral opening ( 30 a, 30 b) of the tunnel tube ( 30 ). 9. Transverse thruster according to claim 8, characterized in that the air supply pipe ( 60 ) is simultaneously the connecting pipe at the seam between the tunnel pipe ( 30 ) or the tunnel pipe side wall and the side wall ( 11 ; 12 ) of the hull ( 10 ) or the ship's outer skin, wherein the air supply pipe ( 60 ) 1. a.) is placed or 2. b.) with a projection ( 60 a) from the plane of the ship's outer skin or the hull side wall ( 11 ) and a projection ( 60 b) from the plane of the side wall of the tunnel tube ( 30 ).