EP3619102A1

EP3619102A1 - Cover device and thruster

Info

Publication number: EP3619102A1
Application number: EP18723752.4A
Authority: EP
Inventors: Holger Spardel; Frank Albrecht; Ulrich ALBRECHT; Kai Danneberg; Uwe Leitloff
Original assignee: SKF Marine GmbH
Current assignee: SKF Marine GmbH
Priority date: 2017-05-02
Filing date: 2018-04-27
Publication date: 2020-03-11
Also published as: WO2018202583A1; JP2020518508A; AU2018263750A1; CN110603190A; DE102017207344A1; US20200130796A1; KR20200002921A; US10988220B2

Abstract

The invention relates to a cover device for closing an underwater opening in the hull of a watercraft at least in some regions, in particular an opening of a transverse channel of a thruster. According to the invention, the cover device has at least one volume-modifiable hollow lip assembly with at least two hollow lips which can be converted into an expanded state or a shrunk state by supplying or discharging a fluid, in particular air. By virtue of the volume-modifiable or inflatable cover device, the cover device can be operated in a reliable manner while requiring little maintenance at the same time. The invention additionally relates to a thruster, in particular a bow or stern thruster.

Description

Covering device and thruster

The invention relates to a covering device for at least partially closing an underwater opening in a hull of a watercraft, in particular an opening of a transverse channel of a thruster. In addition, the invention has a thruster, in particular a bow or stern thruster, the subject.

Modern passenger or cargo ships generally have a variety of submerged openings. Such openings are used for example for sucking cooling water from the fairway and re-introduction of the heated cooling water in the fairway of the ship. Furthermore, to improve the maneuverability of a ship, for example thrusters in the bow and / or tail area may be provided. With favorable flow and weather conditions thrusters can make a costly use of tugs on landing maneuvers, especially for transversal displacement of the ship, unnecessary. However, such thrusters require a hull below the waterline in the bow or stern completely penetrating transverse channel, creating two large-scale opposing openings.

Through the end-side openings of the transverse channel turbulences arise in the water, which lead to an increase in the flow resistance of the hull in the normal operation of a ship. This in turn results in a now unacceptable increase in fuel consumption. This circumstance is due to the often high speeds of freight and passenger ships, which may be in a range of 20 knots, increased importance.

To reduce the flow resistance of a ship's hull in normal driving, for example, circular rotary valves for closing the openings of a Cross channels of a thruster known. By rotating the respective arranged in the region of one of the two opposite openings of the transverse channel rotary valves, the openings can be almost flush with the hull outer skin in the normal operation of the ship. In maneuver operation of the ship, the rotary valves are opened by turning about their longitudinal central axis by 90 °. In the fully open state, the rotary flaps are oriented parallel to the longitudinal direction of the transverse channel, so that a water flow generated by a drive propeller of the thruster can pass through the rotary flaps largely unhindered due to their relative to the diameter of the transverse channel low material thickness.

Years of experience with such rotary valves have shown, however, that in particular their generally diametrically arranged in the opening bearings a high mechanical load by the propeller jet of the thruster, external flow forces and the wave are subject. Furthermore, the bearings of the rotary valves are permanently exposed to the corrosive fairway. All influencing factors can lead to the complete falling out of such a rotary valve alone or in combination with each other in extreme cases.

The object of the invention is therefore to provide a low-maintenance and reliable covering device for an underwater opening in a hull of a watercraft. Moreover, it is an object of the invention to provide a possible low-maintenance thruster for a watercraft.

This object is initially achieved by a covering device having the features of patent claim 1.

The fact that the covering device has at least one volume-variable hollow chamber lip arrangement with at least two hollow-chamber lips and a buoyant body and that the at least one hollow-chamber lip arrangement can be displaced into an expansion state or into a shrink-in state by the supply or removal of a fluid, in particular air, is substantially wear-free and low-maintenance construction of the cover given, which in particular requires no bearings or joints. As a result, a trouble-free operation in corrosive media, in particular in seawater, given. In the state of expansion ensures the high pressure of the introduced fluid or medium sufficient dimensional stability of the Hohlkammerlippenan- order and thus in normal driving reliable closure of the opening in the hull of the ship. The cover device is preferably operated with compressed air or with air that is at a higher pressure than the normal air pressure (1013 hPa), as a fluid that is usually always kept aboard ships. As a fluid, liquids such as water, seawater or oil can also be used. The hollow-chamber lip arrangement can have an approximately semi-oval or tongue-like shape in the expansion state, in the case of an opening with a circular cross-sectional geometry. Alternatively, in the expansion state, in the case of an opening with a circular cross-sectional geometry, the hollow-chamber lip arrangement can have an approximately rectangular or square shape. Preferably, all or individual hollow chamber lips can be brought into an expansion state and into a shrink-in state in order to place the hollow-chamber lip arrangement in an expansion state or in a shrink-in state. An advantage of the configuration of the hollow-chamber lip arrangement of individual hollow-chamber lips is that it is very robust against external disturbing influences during the opening and closing operation. Even in case of failure of a single hollow chamber lip, the hollow-chamber lip arrangement can still be placed in an expansion state or in a Einschrumpfzustand.

According to an advantageous development, it is provided that the hollow-chamber lip arrangement has at least one slippery and tensile shaping element. As a result, when the maximum expansion state is reached, the hollow-chamber lip arrangement can be given a defined shape that is generally deviating from a balloon-shaped geometry, for example a mat-shaped shape. The shaping element may in this case be arranged outside or inside the hollow-chamber lip arrangement. Particularly preferred is an embodiment in which respective shaping elements are arranged within the individual hollow chamber lips. These may be thread-like and determine the cross section of the respective hollow chamber lip in the expansion state. The size and the cross sections of the individual hollow chamber lips may differ, depending on the arrangement of the hollow chamber lip with respect to the hollow chamber lip arrangement. For example, hollow chamber lips in the area a fixed end of the hollow-chamber lip arrangement have a larger cross-section than hollow-chamber lips in the region of a free end of the hollow-chamber lip arrangement. Furthermore, hollow chamber lips in the region of the fixed end in the horizontal direction have a greater extent than in the vertical direction and hollow chamber lips in the region of the free end in the vertical direction have a greater extent than in the horizontal direction.

Preferably, the hollow chamber lip arrangement, or the hollow chamber lips is constructed with a fiuiddichten and flexible sheet. This allows a substantial change in shape of the hollow chamber lip by the supply or the discharge of the fluid. The sheet may be, for example, a flexible and if necessary. elastic film or a fiuiddichten, if necessary. gummierten, textile fabric act whose material thickness is small in relation to its surface area. The individual hollow chamber lips may alternatively be made of a spacer fabric, wherein inside the hollow chamber lips are threads which determine the shape of the respective hollow chamber. The individual hollow chamber lips are in this case connected to one another, for example glued together along a longitudinal extent, so that a hollow chamber lip arrangement in the form of a plate is formed. By appropriate arrangement and gradation of the respective hollow chamber lips to each other a desired shape of the hollow chamber lip arrangement is achieved in the expansion state.

According to a development, the opening in the expansion state of the hollow-chamber lip arrangement is substantially completely closed and substantially completely released in the shrink-in state. As a result, in the normal driving operation of a watercraft, in particular a ship, the opening is virtually completely closed, so that an increase in the flow resistance of the hull in the water is largely excluded.

At least in sections, at least one bistable spring element is preferably arranged in the region of a free end of the hollow-chamber lip arrangement. By the elastic and at the same time bistable element, the change between the state of shrinkage and the expansion state of the hollow chamber lip arrangement is supported. The free end of the hollow chamber lip arrangement extends in the expansion state substantially along a bottom opening section facing the water bottom and in the shrink-in state ideally ends flush with an upper opening section directed away therefrom. The bistable spring element may be formed, for example, with rubber, with plastic, with a metal, in particular with spring steel, or a combination of said materials.

Preferably, a change takes place between the expansion state and the state of shrinkage of the hollow chamber lip arrangement and vice versa due to the bistable spring element. As a result, intermediate states in which the opening is only partially closed by the cover device and released by this, go through quickly. An aspiration of parts of the fabric of the hollow chamber lip by the propeller of the thruster is thus reliably avoided.

Preferably, at least two hollow chamber lips are each equipped with a connection for supplying and / or discharging the fluid. Preferably, all hollow chamber lips are each equipped with its own connection. However, it is also possible for two or more individual hollow chamber lips to be fluidly connected to one another, so that a single connection for filling and emptying is sufficient for these chambers.

A preferred embodiment provides that the at least two hollow-chamber lips can be filled and / or emptied independently of one another via their connection with fluid. It is preferably provided that the at least two hollow chamber uppenes can be filled and / or emptied of fluid independently of one another via their connection. Preferably, the at least two hollow chamber lips can be filled and / or emptied via their connection with different fluid.

In a development, at least in some areas a contact element with a small flow resistance, in particular a grid, is arranged in the opening. As a result, an at least one-side acting, lateral support of the hollow chamber lip arrangement in the direction of the transverse channel is ensured in the expansion state. This investment element can be realized, for example, with gratings, perforated plates, etc. Preferably, the hollow-chamber lip arrangement engages inside the transverse channel from the inside to the contact element. In the case of a preferred embodiment, the at least one hollow-chamber lip arrangement in shrinkage condition is completely accommodated in a storage space and the free end of the hollow-chamber lip arrangement in the expansion state can be accommodated in a recess at least partially in a form-fitting manner. The storage space ensures that the hollow-chamber lip arrangement completely withdraws from the cross-section of the opening in the shrink-in state and that no relevant increase in the flow resistance occurs in the operation of the jet rudder. Due to the depression, an additional securing position of the free end of the hollow-chamber lip arrangement is ensured in its expansion state, which leads to a further improvement of the sealing functionality of the cover. The preferably parallelepiped depression is generally provided in the region of a low point of the lower opening portion of the opening. The term "low point" in the context of the description refers to a fictitious point lying closest to the seabed or a "lower" vertex of the semicircular cross-sectional geometry of the lower opening of the thruster.

Preferably, the at least one buoyant body is arranged in the region of the free end of the hollow-chamber lip arrangement and has a lower density than water. The buoyancy of the buoyant body, which is directed away from the body of water or the seabed or counter to the force of gravity, promotes the transition between the state of expansion and the state of shrinkage of the hollow-chamber lip arrangement. The buoyant body may for example have the shape of a Torusabschnitts. Furthermore, a plurality of preferably uniformly spaced-apart distributed over the free end of the hollow chamber lip arranged buoyant body can be provided. A particularly advantageous embodiment of the buoyant body provides that a hollow chamber lip, preferably the hollow chamber lip forming the free end of the hollow chamber lip arrangement, constitutes the buoyant body. In this case, the hollow chamber lip forming the buoyant body is preferably filled with compressed air in the expansion state of the hollow chamber lip arrangement. When emptying the other hollow chamber lips forming the buoyant body hollow chamber lip pushes the other hollow chamber lips due to their buoyancy and may optionally support the emptying. The other hollow chamber lips can also be filled with compressed air, but it would also be conceivable to provide fluid, for example, surrounding seawater. This would have the part that would not have to be worked against the buoyancy of the fluid during filling. Preferably, the individual hollow chamber lips can be independently of time, for example offset, filled and emptied, which supports the filling and emptying. Thus, preferably, the buoyancy body forming the hollow cavity lip can be filled last and / or emptied last. Furthermore, by a predetermined sequence when filling and / or emptying the individual hollow chamber lips, the hollow chamber lip arrangement can be brought into different end positions. In one embodiment of the buoyant body as a hollow chamber lip can be dispensed with further additional buoyant body.

In addition, the object mentioned by a thruster, in particular a bow or stern thruster, in accordance with claim 10 is achieved.

Due to the fact that the thruster for a watercraft has at least one covering device according to one of the claims 1 to 9, a thruster for a watercraft can be provided, whose transverse channel, which usually has two openings, can be reliably and low-maintenance closed and released again. As a result, the openings can be completely closed during normal driving to minimize the flow resistance and completely released in maneuvering with active thruster. The thruster can be designed, for example, as a bow thruster or as a stern thruster. The covering devices according to the invention can be used without fault-prone mechanical joint and bearing points, which in many cases tend to fail. Furthermore, no fault-prone mechanical drive elements, such as gearboxes or motors, are necessary for operating the cover device.

In the drawing, the same constructive elements have the same reference numerals. In the drawing shows:

1 is a plan view of an underwater opening of a thruster in a hull of a watercraft with a cover in a full state of shrinkage, FIG. 2 is a schematic plan view of the cover device of FIG. 1 in a fully expanded state, and FIG

Fig. 3 is a longitudinal section through the thruster with the covering device of Fig. 1, 2 and a further covering device.

4 shows a plan view of an underwater opening of a thruster in a hull of a watercraft with a covering device according to the invention in a complete state of shrinkage,

5 is a schematic plan view of the covering device of FIG. 4 in a complete expansion state, FIG.

6 shows a longitudinal section through the thruster with a further covering device according to the invention and a further covering device in a complete state of shrinkage

Fig. 7 is a longitudinal section through the thruster with the cover devices of Fig. 6 in a full expansion state.

Figure 1 illustrates a plan view of an underwater orifice of a thruster in a hull of a watercraft having a cover in a full shrink condition.

In a hull 10 of a watercraft 12, which is exemplarily designed as a ship, there is an opening 16 located below water 14 with a circular cross-sectional geometry which can be temporarily closed by means of a covering device 20 according to the invention. The opening 16 is configured here merely by way of example as a control or port-side opening 22 of a transverse channel 24 of a jet rudder 26 which completely passes through the hull 10. The thruster 26 has a drive unit 28 for rotationally driving a propeller 30 in order to generate a strong water flow necessary for easier maneuvering in the transverse channel 24 extending transversely to a longitudinal axis 32 of the hull 10. The thruster 26 may in this case be designed, for example, as a bow or stern thruster 34. Basically, by means of the Cover 20 any submerged openings in a hull of a vessel.

The covering device 20 comprises inter alia a volume-variable, approximately sack-shaped hollow-chamber lip 40 which is completely accommodated in a storage space 42 in the region of the fuselage 10 in the complete "shrink-fit state" shown here, so that the opening 22 is completely released and with the thruster 26 activated Impairment of the water flow in the transverse channel 24 is practically impossible.

Via a tubular connection 44, the hollow chamber lip 40 can be supplied with a fluid 46, in which it is preferably compressed air 48 or another gas, or can be removed or sucked out of it. By a sufficient supply of compressed air 48, the hollow chamber lip 40 in the s. G. "State of expansion", d. H. a completely expanded state (see, in particular, Fig. 2), while the hollow chamber lip 40 by the most complete extraction of the compressed air 48 in the here shown, s. G. "Einschrumpfzustand" is displaceable.

In order to support the transition from the "expansion state" to the "shrink-in state", a buoyant body 50, the density of which is significantly smaller than that of water, is integrated in the hollow chamber lip 40. The hollow chamber lip 40 is provided with a fluid-tight, foldable and as flexible as possible and if necessary. elastic fabric 52 constructed. The buoyant body 50 is here by way of example in the region of a free end 54 of the hollow chamber lip 40 and arranged outside of this. A directed away from the free end 54 fixed end 56 of the hollow chamber lip 40 is mounted in the region of an upper-side cover 58 of the storage space 42. The flat structure 52 of the hollow-chamber lip 40 can be, for example, an optionally fiber-reinforced, high-strength plastic film or an elastomeric film.

Furthermore, the hollow chamber lip 40 has a bistable spring element 60, z. Example, a thick-walled plastic mat, which in the "shrink-in" state shown here extends substantially along an upper opening portion 64 facing away from the body of water 62 and the seabed. The one essentially semicircular transverse Cutting geometry having bistable spring element 60 is used to make any change between the "shrinkage" and the "expansion state" of the hollow chamber lip 40 in the manner of the "crackpot principle" transitionless or jumped as possible to avoid intermediate states. At the upper opening portion 64, a lower opening portion 66 directed towards the water bottom 62 adjoins the circumference. Both the upper and the lower opening portion 64, 66 here each have an approximately semi-cylindrical shape, which together form an approximately circular cross-sectional geometry of the transverse channel 24.

In addition, an abutment element 70 configured by way of example as a grid 68 is provided here, which serves as a one-sided lateral guide for the hollow-chamber lip 40 in its fully expanded state or in the expanded state. Alternatively, another grating, not shown here, may be provided, which runs parallel to the grating 68, so that in the "expansion state" of the hollow chamber lip 40 (cf., in particular, FIG. 2), which is usually in the normal driving mode of the watercraft or of the ship is set to close the opening 22 of the transverse channel 24 - a particularly reliable two-sided guidance of the hollow chamber lip 40 is ensured between the two grids.

FIG. 2 shows a schematic plan view of the covering device of FIG. 1 in the complete "expansion state".

In the "expansion state" the free end 54 of the hollow chamber lip 40 and the bistable spring element 60 extends in the region of the lower opening portion 66, whereby the opening 22 of the thruster 26 is virtually completely closed and in normal driving no significant increase in the flow resistance of the hull 10 of the Watercraft 12 results. The buoyancy body 50 is located in the "expansion state" in the region of a low point 80 of the lower opening portion 66.

Here, the tongue-shaped hollow chamber lip 40 is supported on one side on the grid 68. The change from the "shrink-in state" (see in particular Fig. 1) in the "expansion state" of the hollow chamber lip 40 shown here, takes place by supplying compressed air 48 via the port 44 in the sack-like fabric 52 of the hollow chamber lip 40, which consequently bis up inflates to reach the full "state of expansion". The bistable spring element 60 jumps in the transition from "shrinking" in the "expansion state" abruptly or seamlessly in the position shown here, which is mirror symmetry to the course of the spring element 60 in the shrinkage state and in which the spring element 60 and the free, semi-circular end 54th the hollow chamber lip 40 to ensure optimal sealing effect in the ideal case completely in the region of the lower opening portion 66 of the opening 22 of the thruster 26 abuts.

Fig. 3 shows a longitudinal section through the thruster with the covering device of Fig. 1, 2 and a further covering device.

The thruster 26 comprises the hull 10 of the watercraft 12 under water 14 completely penetrating transverse channel 24. The approximately hollow cylindrical transverse channel 24 has the opening 22 and another, opposite to this introduced into the hull 10 opening 90. Below the hull 10 of the watercraft 12 is located at a distance from the body of water 62. Within the transverse channel 24 of the thruster 26 is the propeller 30 with its at least partially disposed outside of the transverse channel 24 drive unit 28th

The opening 22 of the transverse channel 24 is completely closed or covered by the covering device 20 located here in the "expansion state". By means of the compressed air 48, which is preferably supplied or fed via the connection 44, it is possible to permanently maintain the "expansion state" of the hollow chamber lip 40 in the normal driving operation of the watercraft 12.

In the region of the free end 54 of the hollow chamber lip 40 are the bistable spring element 60 and the buoyancy body 50. By the here perspectively indicated and here realized as a grating 68 contact element 70 experiences the hollow chamber lip 40 a lateral position assurance, so that they always flush with the hull 10th of the watercraft 12 completes and in normal driving a reliable closure of the opening 22 is ensured.

To further optimize the position securing the hollow chamber lip 40 within the opening 22 is in the lower opening portion 66 in the region of the low point 80 at least a cuboid depression 92 or a "trench" running parallel to a ship's longitudinal axis or a "gutter" is provided, in which the free end 54 of the hollow chamber lip 40 can be accommodated in the "expansion state" in a form-fitting manner or can be introduced at least in regions.

Within the hollow-chamber lip 40, only three, for example band-shaped or web-shaped shaping elements 94, 96, 98 are provided here by way of example. This shaping elements 94, 96, 98 can absorb tensile forces, but no significant compressive forces and serve the hollow chamber lip 40 in the expansion state a well-defined, z. B. mat or mattress-like shape. The shaping elements 94, 96 preferably extend approximately parallel to the transverse channel 24, while the individual shaping element 98 extends at an angle α from here, for example only approximately 85 ° inclined to the transverse channel 24. The shaping element 98 can be arranged, for example, between the bistable spring element 60 and the fixed end 56 of the hollow-chamber lip 40 fixed on the upper side in the storage space 42. The shaping elements 94, 96 and 98 may be constructed, for example, with textile tapes having a high tensile strength. Alternatively, the shaping elements 94, 96 and 98 can consist of the same flat structure 52 as the hollow-chamber lip 40 and in this case be configured in a sheet-like manner.

The second opening 90 of the transverse channel 24 of the thruster 26 can be closed by means of a further covering device 110. The cover device 110 for the opening 90 is embodied mirror-symmetrically to the cover device 20, but here, in contrast to the cover device 20, is in the "shrink-in state". Incidentally, the structural design as well as the mode of operation of the covering device 110 corresponds to that of the covering device 20, so that reference is made to the explanations on the covering device 20 at this point (in order to avoid substantive repetitions) (cf., in particular, FIGS. , The hollow crest lip 40 of the cover device 20 does not necessarily have to be downwards, i. H. be formed tapered in the direction of the lower opening portion 66. The same applies to the other cover device 110.

FIG. 4 illustrates a top view of an underwater opening of a thruster in a hull of a watercraft with an alternative cover device in FIG a complete state of shrinkage. In contrast to FIG. 1, not only is a hollow chamber lip 40 provided as a hollow chamber lip arrangement, but the hollow chamber lip arrangement 400 has five separate hollow chamber lips 401, 402, 403, 404, 405. In the further description of FIGS. 4 to 7, only the Differences to Figures 1 to 3 described.

The covering device 20 comprises inter alia a volume-variable, hollow chamber lip arrangement 400, which is completely accommodated in a storage space 42 in the region of the fuselage in the complete "shrinking condition" shown here, so that the opening 22 is completely released and, with the thruster activated, impairment of the Water flow in the transverse channel is virtually eliminated. The five separate hollow chamber lips 401, 402, 403, 404, 405 are all shown in their full "shrink-in" condition, thus showing the hollow chamber lip assembly 400 also in its full "shrink-in" condition. The five separate hollow-chamber lips 401, 402, 403, 404, 405 each have their own connection 441, 442, 443, 444, 445, which is essentially tubular and has a tubular end-side and over which the individual hollow-chamber lips 401, 402, 403, 404, 405 a fluid, which is preferably compressed air or another gas, can be supplied or removed or sucked out of these. The ports 441, 442, 443, 444, 445 of all the hollow chamber lips are arranged on the hollow chamber lips 401, 402, 403, 404, 405 so that they lie outside of the opening 22 both in the "expansion state" and in the "shrink-in state". For this purpose, the connection 441 of the hollow-chamber lip 401, which forms the fixed end 56 of the hollow-chamber lip arrangement 400, is arranged centrally on the hollow-chamber lip 401. The ports 442, 443, 444 and 445 of the other hollow chambers are arranged alternately left and right at the lateral ends of the hollow chamber lips 402, 403, 404 and 405 space-optimized and connected by means of a tubular flexible intermediate piece with the hollow chamber lips.

By a sufficient supply of compressed air in all the hollow chamber lips 401, 402, 403, 404, 405, the hollow chamber lip assembly 400 in the so-called "expansion state", ie a fully expanded state (see Fig .. Fig. 5) offset, while the hollow-chamber lip assembly 40 through the most complete suction or drain the Compressed air from all hollow chamber lips 401, 402, 403, 404, 405) in the here shown, so-called "shrinkage" is displaceable.

A separate buoyancy body 50, which supports the transition from the "expansion state" into the "shrink-in state", as in FIGS. 1 to 3, is dispensed with in the exemplary embodiment of FIGS. 4 to 7. The buoyant body is formed in FIGS. 4 to 7 by the hollow-chamber lip 405 forming the free end 54 of the hollow-chamber lip arrangement 400. For this purpose, the hollow chamber lip 405 is acted upon via its port 445 with compressed air wherein the hollow chamber lip 405 at a transition from the "expansion state" in the "shrinking" of the hollow chamber lip assembly 400 preferably as the last of the hollow chamber lips 401, 402, 403, 404, 405 completely emptied, respectively is brought into the "shrinking". The hollow chamber lip 405 filled with air thus represents the buoyant body and lifts the emptied hollow chamber lips 401, 402, 403, 404 into the storage space 42. However, a separate buoyant body could additionally be arranged in or on the hollow chamber lip 405. However, it can also be dispensed with entirely on a separate buoyancy body, so that the hollow chamber lip 401, or optionally further hollow chamber lips constitute the one or more buoyancy bodies. For example, in a successive emptying of the hollow chamber lips from top to bottom, all lower-lying hollow chamber lips are buoyant body for the overlying hollow chamber lips.

A spring element 60 which supports the transition from the "expansion state" into the "shrink-in state", as in FIGS. 1 to 3, is dispensed with in the exemplary embodiments of FIGS. 4 to 7.

FIG. 5 shows a schematic plan view of the cover device of FIG. 4 in the complete "expansion state".

In the "expansion state" the free end 54 of the hollow chamber lip assembly 400, which is formed by the hollow chamber lip 405 in the region of the lower opening portion, whereby the opening 22 of the thruster is almost completely closed and in normal driving no significant increase in the flow resistance of the hull of the vessel results. The buoyancy body which of the Hollow chamber lip 405 is located in the "expansion state" in the region of a low point of the lower opening portion.

The change from the "shrink-in state" (cf., in particular, FIG. 4) into the "expansion state" of the hollow-chamber lip arrangement 400 shown here takes place by supplying compressed air via the connections 441, 442, 443, 444, 445 into the tubular hollow-chamber lips 401, 402, 403, 404, 405 which, as a result, inflate until full "expansion state" is reached. In principle, the upper tubular hollow-chamber lips 401, 402, 403, 404 could be filled with seawater as fluid and only the hollow-chamber lip 405 as buoyant body could be filled with compressed air in order to represent the functionality of the covering device 20.

FIG. 6 shows a longitudinal section through the thruster with a further covering device according to the invention and a further covering device in a complete state of shrinkage

The thruster 26 comprises the hull 10 of the watercraft 12 under water 14 completely penetrating transverse channel 24. The approximately hollow cylindrical transverse channel 24 has the opening 22 and another, opposite to this introduced into the hull 10 opening 90. Below the hull 10 of the watercraft 12 is spaced the river bottom. Within the transverse channel 24 of the thruster 26, the propeller 30 is located with its at least partially disposed outside of the transverse channel 24 drive unit 28th

The two cover device 20 and 110 for the openings 22 and 90 of the transverse channel 24 are mirror-symmetrical to each other and are in the "shrinking". The covering devices 20 and 110 consist essentially of the hollow-chamber lips 401, 402, 403, 404, 405, which can accommodate different volumes and also require different volumes in the storage space 42 in the "shrink-in state". The hollow-chamber lips 401, 402, 403, 404, 405 can each be filled with compressed air via their own connections, with only the connection 441 of the uppermost hollow-chamber lip 401 being shown in FIG. Fig. 7 shows a longitudinal section through the thruster with the cover devices of Fig. 6 in a fully expanded state

The opening 22 of the transverse channel 24 is completely closed or covered by the covering device 20 located here in the "expansion state". By means of the compressed air 48, which is preferably constantly supplied or fed via the ports 441, 442, 443, 444, 445, a permanent maintenance of the "expansion state" of the hollow chamber lips 401, 402, 403, 404, 405 forming the hollow chamber lip arrangement 400 is normal Driving operation of the watercraft 12 possible.

The hollow chamber lip 405 in the region of the free end 54 of the hollow chamber lip arrangement 400 forms a buoyancy body 50. By means of the contact element realized here in perspective and realized here as a grating 68, the hollow chamber lips 401, 402, 403, 404, 405 experience lateral securing, so that these always flush with the hull 10 of the vessel 12 complete and a reliable closure of the opening 22 is ensured in normal driving. The hollow chamber lips 401, 402, 403, 404, 405 are located on the side of the grid 68 within the transverse channel 24.

In order to further optimize the position securing of the hollow chamber lip arrangement 400 within the opening 22, at least one, for example cuboid recess 92 or a "trench" running parallel to a ship's longitudinal axis or a "gutter" is provided in the lower opening section 66 in the region of the low point the lowermost hollow chamber lip 445 which forms the free end 54 of the hollow chamber lip arrangement 400 in the "expansion state" is at least partially positively receivable or can be introduced therein.

Within the hollow-chamber lip 401, only two, for example thread-like, band-shaped or web-shaped shaping elements 94 are provided here by way of example. Within the hollow chamber lip 405 are also two only example, for example, thread, ribbon or web-shaped forming elements 96, respectively. It is understood that the other hollow chamber lips 402, 403, 404 may have shaping elements. Furthermore, outside of the hollow chamber lips, another shaping element 98, which spans the hollow chamber lips 401, 402, 403, 404, 405, is arranged. These Forming elements 94, 96, 98 can absorb tensile forces, but no significant compressive forces and serve the hollow chamber lip assembly 404 in the expansion state a well-defined, z. B. mat or mattress-like shape. The shaping elements 94, 96 and 98 may be constructed, for example, with textile tapes having a high tensile strength. Alternatively, the shaping elements 94, 96 and 98 can consist of the same flat structure 52 as the hollow-chamber lips 401, 402, 403, 404, 405 and in this case be designed in the form of a web.

The hollow chamber lips may alternatively consist of a spacer fabric and the shaping elements 94, 96 of associated threads.

The second opening 90 of the transverse channel 24 of the thruster is closed by means of a further covering device 110, which is designed mirror-symmetrically to the cover 20 and is also in the "expansion state". Moreover, the structural design and the operation of the cover 110 correspond to those of the cover 20, so that at this point - to avoid substantive repetition - reference is made to the explanations to the cover 20. The hollow-chamber lips 401, 402, 403, 404, 405 of the covering devices 20, 110 need not have the same axial length as in FIG. 5, so that in the "expansion state" the hollow-chamber lip arrangement 400 is rectangular or square, but can also have different lengths , For example, down, that is from the hollow chamber lip 401 to the hollow chamber lip 405 out, decreasing lengths, whereby a downwardly, ie tapered in the direction of the lower opening portion formed hollow-chamber lip assembly 400 may be shown.

Notwithstanding the possibility given by way of example only in FIGS. 1 to 7 to close the two-sided openings of a transverse duct of a thruster with one of the covering devices according to the invention, other openings lying below the waterline of a ship can be made closable by means of the covering device according to the invention.

By way of example, reference may be made here to the possibility of a covering device for an opening for a stabilizer of a ship, in which the stabilizer is accommodated in a stabilizer chamber in the ship's hull and can be pivoted in and out of it in this manner. is net. An alternative embodiment, not shown, the cover device can be designed so that the one cover has two separate hollow chamber lip arrangements, each having a plurality of hollow chamber lips are volume changeable by the supply or discharge of a fluid and thereby the two hollow chamber lip arrangements in an expansion state or in a Shrinked state are displaceable. The two hollow-chamber lip arrangements each have a fixed end and a free end, with the fixed ends being arranged at the upper and lower opening sections, and the two free ends, each of which can be represented by a hollow-chamber lip, filling the hollow-chamber lip arrangement in the direction of the center of the Move toward each other and in the expansion state in a central region of the opening either abut each other and thus close the opening or each rest on a surface of the stabilizer and thus close the opening. At least for the upper of the two hollow-chamber lip arrangements, a hollow-chamber lip forming the free end can form a buoyant body, which can be used to support the emptying of the hollow-chamber lip arrangement.

As a result of the structurally simple structure of the volume changeable or inflatable hollow chamber lip arrangement - essentially without mechanically movable components, in particular bearings, joints, motors and gears, gets along - a lifetime, reliable and low-maintenance operation of the cover is guaranteed.

The invention relates to a covering device for at least partially closing an underwater opening in a hull of a watercraft, in particular an opening of a transverse channel of a thruster. According to the invention, the covering device has at least one volume-variable hollow-chamber lip arrangement with at least two hollow-chamber lips, and the at least two hollow-chamber lips can be set into an expansion state or into a shrink-in state by the supply or removal of a fluid, in particular air. As a result of the volume changeable or inflatable covering device, a reliable and at the same time low-maintenance operation of the covering device is provided. In addition, the invention has a thruster, in particular a bow or stern thruster to the object. LIST OF REFERENCE NUMBERS

10. Hull 80th low point

12. Watercraft

14. Water

16. Opening (general)

90th opening (transverse channel)

20. Cover device 92. depression

22. Opening (transverse channel) 94. Shaping element

24. Transverse channel (thruster) 96. Shaping element

26. Thruster 98. Shaping element

28. Drive unit

30. Propeller

32. longitudinal axis (fuselage)

34. Bow or stern thruster 110. Covering device

40. hollow chamber lip 400. hollow chamber lip arrangement

42. Storage room 401. Hollow chamber lip

44. Connection 402. Hollow chamber lip

46. Fluid 403. Hollow-chamber lip

48. Compressed air (air) 404. Hollow chamber lip

50. buoyancy body 405. hollow chamber lip

52. fabrics

54. free end 441. connection

56. Fixed end 442. Connection

58. Lid (storage room) 443. Connection

60. bistable spring element 444. connection

62. Riverbed 445. Connection

64th upper opening section

66th lower opening section

68. Grid

70. contact element

Claims

P a n t a n s p r e c h e

Covering device and thruster

Covering device (20, 110) for at least partially closing an underwater opening (16, 22, 90) in a hull (10) of a watercraft (12), in particular an opening (22, 90) of a transverse channel (24) of a thruster ( 26), wherein the covering device (20, 110) has a volume-changeable hollow-chamber lip arrangement (400) with at least two hollow-chamber lips (401, 402, 403, 404, 405) and a buoyant body (50), wherein at least one hollow-chamber lip (401, 402, 403 , 404, 405) is variable in volume by the supply or discharge of a fluid (46) and thereby the hollow chamber lip assembly (400) is displaceable in an expansion state or in a Einschrumpfzustand.

Covering device (20, 110) according to claim 1, characterized in that the hollow chamber lip arrangement (400) has at least one slippery and tensile forming element (94, 96, 98).

Covering device (20, 110) according to one of claims 1 or 2, characterized in that the hollow chamber lips (401, 402, 403, 404, 405) is constructed with a fluid-tight and flexible sheet (52).

Covering device (20, 110) according to one of the claims 1 to 3, characterized in that the opening (16, 22, 90) is substantially completely closed in the expansion state of the hollow-chamber lip arrangement (400) and is substantially completely released in the shrink-in state.

5. covering device (20, 110) according to one of the claims 1 to 4, characterized in that at least two hollow chamber lips (401, 402, 403, 404, 405) each having a port (441, 442, 443, 444, 445) for supplying and / or discharging the fluid.

6. covering device (20, 110) according to claim 5, characterized in that the at least two hollow chamber lips (401, 402, 403, 404, 405) via their connection (441, 442, 443, 444, 445) filled independently with fluid or / and can be emptied.

7. covering device (20, 110) according to one of the claims 1 to 6, characterized in that in the opening (16, 22, 90) at least partially a contact element (70) with a small flow resistance, in particular a grid (68) arranged is.

8. covering device (20, 110) according to one of the claims 1 to 7, characterized in that the at least one hollow chamber lip arrangement (400) in the shrinkage condition completely in a storage space (42) and the free end (54) hollow chamber lip arrangement (400) in the expansion state at least partially positively in a recess (92) is receivable.

9. covering device (20, 110) according to one of the claims 1 to 8, characterized in that the at least one buoyancy body (50) in the region of a free end (54) of the hollow chamber lip assembly (400) is arranged and has a lower density than water, wherein the buoyant body (50) is configured to have a buoyancy force that assists in the transition between the expansion state and the shrink-in state of the hollow chamber lip assembly (400)

10. thruster (26), in particular bow or stern thruster (34), for a watercraft (12) with at least one covering device (20, 110) according to one of the claims 1 to 9 for covering at least one opening (22, 90) of a transverse channel (24) of the thruster (26).