Method and Arrangement for Sealing a Propeller Shaft of a Marine Vessel

Abstract

A method and an arrangement for sealing a propeller shaft. The propeller shaft is rotatably supported with a bearing arrangement inside a pod that is suspended at a hull of the marine vessel. The bearing arrangement includes at least two seal rings axially spaced apart from each other such that at least one lubricant seal chamber is delimited. The arrangement includes a lubrication arrangement for conducting lubricant to and from said bearing arrangement. The lubrication arrangement includes an additional lubrication circulation line for conducting a part of said flow of lubricant to and from said at least one lubricant seal chamber. The lubrication arrangement being additionally configured to create a flow of lubricant in the additional lubricant circulation line and in said at least one lubricant seal chamber.

Description

TECHNICAL FIELD

The invention relates to a method for sealing a propeller shaft of a marine vessel as defined in the preamble of independent claim, wherein the propeller shaft is arranged at a pod that is suspended at a hull of the marine vessel, wherein a propeller is attached to a driving end of the propeller shaft, wherein the driving end projects out of the pod, wherein the propeller shaft is rotatably supported with a bearing arrangement inside the pod, wherein at least two seal rings are provided axially spaced apart from each other in an axial direction of the propeller shaft and engaging the outer circumference of the propeller shaft such that at least one lubricant seal chamber is delimited between adjacent seal rings, and wherein the bearing arrangement comprises a lubrication arrangement comprising a lubricant circulation line for conducting lubricant to said bearing arrangement and for conducting lubricant from said bearing arrangement, and a lubricant circulator configured to create a flow of lubricant in the lubricant circulation line and in the bearing arrangement.

The invention also relates to an arrangement for sealing a propeller shaft of a marine vessel as defined in the preamble of independent claim, wherein the propeller shaft is arranged at a pod that is suspended at a hull of the marine vessel, wherein a propeller is attached to a driving end of the propeller shaft, wherein the driving end projects out of the pod, wherein the propeller shaft is rotatably supported with a bearing arrangement inside the pod, wherein at least two seal rings are provided axially spaced apart from each other in an axial direction of the propeller shaft and engaging the outer circumference of the propeller shaft such that at least one lubricant seal chamber is delimited between adjacent seal rings, and wherein the arrangement comprises a lubrication arrangement comprising a lubricant circulation line for conducting lubricant to said bearing arrangement and for conducting lubricant from said bearing arrangement, and a lubricant circulator configured to create a flow of lubricant in the lubricant circulation line and in the bearing arrangement.

A problem with the above presented method and arrangement is the heating of the seal rings delimiting the lubricant seal chamber with leads to wear and reduced service-life of the seal rings. The seal rings are heated due to the friction between the propeller shaft and the seal rings, because the seal rings engage the outer circumference of the rotating propeller shaft.

SUMMARY

The object of the invention is to provide a method and an arrangement for sealing a propeller shaft of a marine vessel to solve the mentioned problem.

The method is characterized by the definitions of independent claim.

Preferred embodiments of the method are defined in the dependent claims.

The arrangement is correspondingly characterized by the definitions of independent claim.

Preferred embodiments of the arrangement are defined in the dependent claims.

BRIEF DESCRIPTION OF DRAWINGS

In the following the invention will described in more detail by referring to the figures, which

FIG. 1 illustrates a first embodiment of the arrangement,

FIG. 2 illustrates a second embodiment of the arrangement,

FIG. 3 illustrates a third embodiment of the arrangement,

FIG. 4 illustrates a fourth embodiment of the arrangement, and

FIG. 5 illustrates a fifth embodiment of the arrangement.

DETAILED DESCRIPTION

First the method for sealing a propeller shaft 1 of a marine vessel 2 and some embodiments and variants of the method will be described in greater detail.

In the method the propeller shaft 1 is arranged at a pod 3 that is suspended at a hull 4 of the marine vessel 2.

The pod 3 can be fixedly suspended at the hull 4 of the marine vessel 2. It is also possible that the pod 3 is pivotable about a pivot axis (not illustrated) suspended at the hull 4 of the marine vessel 2. Inside the pod 3 can an electric motor (not illustrated) be provided for rotating the propeller shaft 1. It is also possible that the pod comprises a mechanical power transmission arrangement for rotating the propeller shaft 1 by means of a motor arranged as housed by the hull 4 of the marine vessel 1.

In the method a propeller 5 is attached to a driving end 6 of the propeller shaft 1, wherein the driving end 6 projects out of the pod 3. The propeller shaft 1 can additionally have a second driving end (not illustrated) that projects out of an opposite end of the pod 3 i.e. so that the propeller projects through the pod and so that a second propeller (not illustrated) is provided as the second driving end.

In the method the propeller shaft 1 can have a non-driving section 7 that is inside the pod 3,

In the method the propeller shaft 1 is rotatably supported with a bearing arrangement 8 inside the pod 3.

In the method at least two seal rings 9 are provided axially spaced apart from each other in an axial direction of the propeller shaft 1 and engaging the outer circumference of the propeller shaft 1 such that at least one lubricant chamber 10 is delimited between adjacent seal rings 9.

The propeller shaft 1 can comprise a liner 20 that at least partly forms the outermost part of the propeller shaft 1. In the figures, the liner 20 forms the outermost part of the propeller shaft 1 at least in the region of the seal rings 11.

In the method the bearing arrangement comprises a lubrication arrangement 11 comprising a lubricant circulation line 12 for conducting lubricant to said bearing arrangement 8 and for conducting lubricant from said bearing arrangement 8, and a lubricant circulator 13 configured to create a flow of lubricant in the lubricant circulation line 12 and in the bearing arrangement 8.

The method comprises providing the lubrication arrangement 11 with an additional lubrication circulation line 14 comprising a first line part 15 for conducting a part of said flow of lubricant to said at least one lubricant seal chamber 10 and comprising a second line part 16 for conducting said part of said flow of lubricant from said at least one lubricant seal chamber 10.

The method comprises creating a flow of lubricant in the first line part 15 and in the second line part 16 of the additional lubrication circulation line 14 and in said at least one lubricant seal chamber 10.

The method can comprise creating by means of the lubricant circulator 13 the flow of lubricant in the first line part 15 and in the second line part 16 of the additional lubrication circulation line 14 and in said at least one lubricant seal chamber 10.

It is also possible that the first line part 15 and/or the second line part 16 of the additional lubrication circulation line comprises or is provided with an additional lubricant circulator (not illustrated in the figures) configured to create the flow of lubricant in the first line part 15 and in the second line part 16 of the additional lubrication circulation line 14 and in said at least one lubricant seal chamber 10.

Said flow of lubricant in said at least one lubricant seal chamber 10 will lower the temperature in said at least one lubricant seal chamber 10 and consequently lower the temperature of the seal rings 9 delimiting said at least one lubricant seal chamber 10. This reduces wearing of the seal rings 9 and extends the service-life of the seal rings 9. One reason for the temperature being lower is that because the temperature of the lubricant that is circulated in said at least one lubricant seal chamber 10 is lower than the temperature resulting from the friction between the outer circumference of the rotating propeller shaft 1 and said seal rings 9, thermal energy will be conducted from the seal rings 9 to the lubricant that is circulated in said at least one lubricant seal chamber 10 and in the second line part 16 away from said at least one lubricant seal chamber 10.

The method can comprise connecting the first line part 15 in fluid connection with the 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10, and connecting the first line part 15 in fluid connection with said at least one lubricant seal chamber 10 and conducting said part of said flow of lubricant from the lubricant circulation line 12 to said at least one lubricant seal chamber 10 in the first line part 15.

The method can comprise connecting the first line part 15 in fluid connection with the lubricant circulation line 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10, and connecting the first line part 15 in fluid connection with a bottom of said at least one lubricant seal chamber 10 and conducting said part of said flow of lubricant from the lubricant circulation line 12 into the bottom of said at least one lubricant seal chamber 10 in the first line part 15.

The method can comprise connecting the first line part 15 in fluid connection with a bottom of the bearing arrangement 8 and connecting the first line part 15 in fluid connection with a bottom of said at least one lubricant seal chamber 10 and conducting said part of said flow of lubricant from the bottom of the bearing arrangement 8 into the bottom of said at least one lubricant seal chamber 10 in the first line part 15.

The method can comprise providing the second line part 16 by means an equalizing channel between said at least one lubricant seal chamber 10 and the bearing arrangement 8 and conducting said part of said flow of lubricant from said at least one lubricant seal chamber 10 to the bearing arrangement 8 in the second line part 16.

The method can comprise connecting the second line part 16 in fluid connection with a top of said at least one lubricant seal chamber 10 and in fluid connection with the bearing arrangement 8 and conducting said part of said flow of lubricant from the top of said at least one lubricant seal chamber 10 into the bearing arrangement 8 in the second line part 16.

The method can comprise connecting the second line part 16 in fluid connection with a bottom of said at least one lubricant seal chamber 10 and in fluid connection with the lubricant circulation line 12 at a point downstream of the bearing arrangement 8 and upstream of the lubricant circulator 13 and conducting said part of said flow of lubricant from the bottom of said at least one lubricant seal chamber 10 into the lubricant circulation line 12 in the second line part 16.

The second embodiment illustrated in FIG. 2 comprises connecting the first line part 15 in fluid connection with the lubricant circulation line 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10, and connecting the first line part 15 in fluid connection with said at least one lubricant seal chamber 10 and conducting said part of said flow of lubricant from the lubricant 15 circulation line 12 to said at least one lubricant seal chamber 10 in the first line part 15, and providing the second line part 16 by means an equalizing channel between said at least one lubricant seal chamber 10 and the bearing arrangement 8 and conducting said part of said flow of lubricant from said at least one lubricant seal chamber 10 to the bearing arrangement 8 in the second line part 16.

The third embodiment illustrated in FIG. 3 comprises connecting the first line part 15 in fluid connection with the lubricant circulation line 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10, and connecting the first line part 15 in fluid connection with a bottom of said at least one lubricant seal chamber 10 and conducting said part of said flow of lubricant from the lubricant circulation line 12 into the bottom of said at least one lubricant seal chamber 10 in the first line part 15, and connecting the second line part 16 in fluid connection with a top of said at least one lubricant seal chamber 10 and in fluid connection with the bearing arrangement 8 and conducting said part of said flow of lubricant from the top of said at least one lubricant seal chamber 10 into the bearing arrangement 8 in the second line part 16. By adjusting the height or the second line part 16 can the pressure in said at least one lubricant seal chamber 10 be adjusted. A higher height or the second line part 16 results in a higher lubricant level and into a higher pressure in in said at least one lubricant seal chamber 10 and this seals said at least one lubricant seal chamber 10 better and prevents thus leakage. A higher pressure also extends the service-life of said at least two seal rings 9. Because said at least one lubricant seal chamber 10 will be full with lubricant, said at least two seal rings 9 will have a longer service-life.

The fourth embodiment illustrated in FIG. 4 comprises connecting the first line part 15 in fluid connection with a bottom of the bearing arrangement 8, and connecting the first line part 15 in fluid connection with a bottom of said at least one lubricant seal chamber 10 and conducting said part of said flow of lubricant from the bottom of the bearing arrangement 8 into the bottom of said at least one lubricant seal chamber 10 in the first line part 15, and connecting the second line part 16 in fluid connection with a bottom of said at least one lubricant seal chamber 10 and in fluid connection with the lubricant circulation line 12 at a point downstream of the bearing arrangement 8 and upstream of the lubricant circulator 13 and conducting said part of said flow of lubricant from the bottom of said at least one lubricant seal chamber 10 into the lubricant circulation line 12 in the second line part 16.

The method comprises preferably, but not necessarily, conducting thermal energy from lubricant circulating in the lubricant circulation line 12 with a cooler 17 provided in thermal contact with the lubricant circulation line 12. This additionally promotes cooling of said at least two seal rings 9. The cooler 17 can be arranged within the pod 3 as illustrated in FIGS. 1 to 4 or outside the pod and within the hull 4 of the marine vessel 2 as illustrated in FIG. 5.

The method comprises preferably, but not necessarily, regulating the flow of lubricant in the first line part 15 by means of a throttle means 18 provided in the first line part 15. Instead of a throttle means 18 can another type of flow regulating means be used.

Next the arrangement for sealing a propeller shaft 1 of a marine vessel 2 and some embodiments and variants of the method will be described in greater detail.

The propeller shaft 1 is arranged at a pod 3 that is suspended at a hull 4 of the marine vessel 2.

The pod 3 can be fixedly suspended at the hull 4 of the marine vessel 2. It is also possible that the pod 3 is pivotable about a pivot axis (not illustrated) suspended at the hull 4 of the marine vessel 2. Inside the pod 3 can an electric motor (not illustrated) be provided for rotating the propeller shaft 1. It is also possible that the pod comprises a mechanical power transmission arrangement for rotating the propeller shaft 1 by means of a motor arranged as housed by the hull 4 of the marine vessel 1.

A propeller 5 is attached to a driving end 6 of the propeller shaft 1, wherein the driving end 6 projects out of the pod 3. The propeller shaft 1 can have a non-driving section 7 that is inside the pod 3. The propeller shaft 1 can additionally have a second driving end (not illustrated) that projects out of an opposite end of the pod 3 i.e. so that the propeller projects through the pod and so that a second propeller (not illustrated) is provided as the second driving end.

The propeller shaft 1 is rotatably supported with a bearing arrangement 8 inside the pod 3.

At least two seal rings 9 are provided axially spaced apart from each other in an axial direction of the propeller shaft 1 and engaging the outer circumference of the propeller shaft 1 such that at least one lubricant seal chamber 10 is delimited between adjacent seal rings 9.

The propeller shaft 1 can comprise a liner 20 that at least partly forms the outermost part of the propeller shaft 1. In the figures, the liner 20 forms the outermost part of the propeller shaft 1 at least in the region of the seal rings 11.

The arrangement comprises a lubrication arrangement 11 comprising a lubricant circulation line 12 for conducting lubricant to said bearing arrangement 8 and for conducting lubricant from said bearing arrangement 8, and a lubricant circulator 13 configured to create a flow of lubricant in the lubricant circulation line 12 and in the bearing arrangement 8.

In the arrangement the lubrication arrangement comprises an additional lubrication circulation line 14 for conducting a part of said flow of lubricant to said at least one lubricant seal chamber 10 and for conducting said part of said flow of lubricant from said at least one lubricant seal chamber 10 and the lubrication arrangement being additionally configured to create a flow of lubricant in the additional lubricant circulation line 14 and in said at least one lubricant seal chamber 10.

In the arrangement the lubricant circulator 13 of the lubrication arrangement is preferably, but not necessarily, additionally configured to create the flow of lubricant in the additional lubricant circulation line 14 and in said at least one lubricant seal chamber 10.

In the arrangement it is also possible that the additional lubricant circulation line 14 is provided with an additional lubricant circulator (not illustrated in the figures) configured to create the flow of lubricant in the additional lubricant circulation line 14 and in said at least one lubricant seal chamber 10.

Said flow of lubricant in said at least one lubricant seal chamber 10 will lower the temperature in said at least one lubricant seal chamber 10 and consequently lower the temperature of the seal rings 9 delimiting said at least one lubricant seal chamber 10. This reduces wearing of the seal rings 9 and extends the service-life of the seal rings 9. One reason for the temperature being lower is that because the temperature of the lubricant that is circulated in said at least one lubricant seal chamber 10 is lower than the temperature resulting from the friction between the outer circumference of the rotating propeller shaft 1 and said seal rings 9, thermal energy will be conducted from the seal rings 9 to the lubricant that is circulated in said at least one lubricant seal chamber 10 and in the second line part 16 away from said at least one lubricant seal chamber 10.

In the arrangement the first line part 15 can be in fluid connection with the lubricant circulation line 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10 and in fluid connection with said at least one lubricant seal chamber 10, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from the lubricant circulation line 12 to said at least one lubricant seal chamber 10.

In the arrangement the first line part 15 can be in fluid connection with the lubricant circulation line 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10 and in fluid connection with a bottom of said at least one lubricant seal chamber 10, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from the lubricant circulation line 12 into the bottom of said at least one lubricant seal chamber 10.

In the arrangement the first line part 15 can be in fluid connection with a bottom of the bearing arrangement, and in fluid connection with a bottom of said at least one lubricant seal chamber 10, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from the bottom of the bearing arrangement 8 into the bottom of said at least one lubricant seal chamber 10.

In the arrangement the second line part 16 can be formed by an equalizing channel between said at least one lubricant seal chamber 10 and the bearing arrangement 8, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from said at least one lubricant seal chamber 10 to the bearing arrangement 8.

In the arrangement the second line part 16 can be in fluid connection with a top of said at least one lubricant seal chamber 10 and in fluid connection with the bearing arrangement 8, wherein the second line part 16 being configured to conduct said part of said flow of lubricant from the top of said at least one lubricant seal chamber 10 into the bearing arrangement 8.

In the arrangement the second line part 16 can be in fluid connection with a bottom of said at least one lubricant seal chamber 10 and in fluid connection with the lubricant circulation line 12 at a point downstream of the bearing arrangement 8 and upstream of the lubricant circulator 13, wherein the second line part 16 being configured to conduct said part of said flow of lubricant from the bottom of said at least one lubricant seal chamber 10 into the lubricant circulation line 12.

In the second embodiment of the arrangement illustrated in FIG. 2, the first line part 15 is in fluid connection with the lubricant circulation line 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10 and in fluid connection with said at least one lubricant seal chamber 10, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from the lubricant circulation line 12 to said at least one lubricant seal chamber 10, and the second line part 16 is formed by an equalizing channel between said at least one lubricant seal chamber 10 and the bearing arrangement 8, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from said at least one lubricant seal chamber 10 to the bearing arrangement 8.

In the third embodiment of the arrangement illustrated in FIG. 3, the first line part 15 is in fluid connection with the lubricant circulation line 12 at a point downstream of the lubricant circulator 13 and upstream of said at least one lubricant seal chamber 10 and in fluid connection with a bottom of said at least one lubricant seal chamber 10, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from the lubricant circulation line 12 into the bottom of said at least one lubricant seal chamber 10, and the second line part 16 is in fluid connection with a top of said at least one lubricant seal chamber 10 and in fluid connection with the bearing arrangement 8, wherein the second line part 16 being configured to conduct said part of said flow of lubricant from the top of said at least one lubricant seal chamber 10 into the bearing arrangement 8. By adjusting the height or the second line part 16 can the pressure in said at least one lubricant seal chamber 10 be adjusted. A higher height or the second line part 16 results in a higher lubricant level and into a higher pressure in in said at least one lubricant seal chamber 10 and this seals said at least one lubricant seal chamber 10 better and prevents thus leakage. A higher pressure also extends the service-life of said at least two seal rings 9. Because said at least one lubricant seal chamber 10 will be full with lubricant, said at least two seal rings 9 will have a longer service-life.

In the fourth embodiment of the arrangement illustrated in FIG. 4, the first line part 15 is in fluid connection with a bottom of the bearing arrangement, and in fluid connection with a bottom of said at least one lubricant seal chamber 10, wherein the first line part 15 being configured to conduct said part of said flow of lubricant from the bottom of the bearing arrangement 8 into the bottom of said at least one lubricant seal chamber 10, and the second line part 16 is in fluid connection with a bottom of said at least one lubricant seal chamber 10 and in fluid connection with the lubricant circulation line 12 at a point downstream of the bearing arrangement 8 and upstream of the lubricant circulator 13, wherein the second line part 16 being configured to conduct said part of said flow of lubricant from the bottom of said at least one lubricant seal chamber 10 into the lubricant circulation line 12.

The arrangement comprises preferably, but not necessarily, a cooler 17 provided in thermal contact with the lubricant circulation line 12, which cooler 17 is configured to conduct thermal energy from lubricant circulating in the lubricant circulation line 12. This additionally promotes cooling of said at least two seal rings 9. The cooler 17 can be arranged within the pod 3 as illustrated in FIGS. 1 to 4 or outside the pod and within the hull 4 of the marine vessel 2 as illustrated in FIG. 5.

The arrangement comprises preferably, but not necessarily, a throttle means 18 provided in the first line part 15, which throttle means 18 is configured to regulate the flow of lubricant in the first line part 15. Instead of a throttle means 18 can another type of flow regulating means be used.

It is apparent to a person skilled in the art that as technology advanced, 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 method for sealing a propeller shaft of a marine vessel, wherein the propeller shaft is arranged at a pod that is suspended at a hull of the marine vessel,wherein a propeller is attached to a driving end of the propeller shaft, wherein the driving end projects out of the pod,wherein the propeller shaft is rotatably supported with a bearing arrangement inside the pod,wherein at least two seal rings are provided axially spaced apart from each other in an axial direction of the propeller shaft and engaging the outer circumference of the propeller shaft such that at least one lubricant seal chamber is delimited between adjacent seal rings, andwherein the bearing arrangement comprises a lubrication arrangement having a lubricant circulation line for conducting lubricant to said bearing arrangement and for conducting lubricant from said bearing arrangement, and a lubricant circulator configured to create a flow of lubricant in the lubricant circulation line and in the bearing arrangement,wherein providing the lubrication arrangement with an additional lubrication circulation line including a first line part for conducting a part of said flow of lubricant to said at least one lubricant seal chamber and including a second line part for conducting said part of said flow of lubricant from said at least one lubricant seal chamber, and by creating a flow of lubricant in the first line part and in the second line part of the additional lubricant circulation line and in said at least one lubricant seal chamber.

2. The method according to claim 1, wherein creating the flow of lubricant in the first line part and in the second line part of the additional lubricant circulation line and in said at least one lubricant seal chamber by means of the lubricant circulator.

3. The method according to claim 1wherein connecting the first line part in fluid connection with the lubricant circulation line at a point downstream of the lubricant circulator and upstream of said at least one lubricant seal chamber, and connecting the first line part in fluid connection with said at least one lubricant seal chamber, andby conducting said part of said flow of lubricant from the lubricant circulation line to said at least one lubricant seal chamber in the first line part.

4. The method according to claim 1wherein connecting the first line part in fluid connection with the lubricant circulation line at a point downstream of the lubricant circulator and upstream of said at least one lubricant seal chamber, and connecting the first line part in fluid connection with a bottom of said at least one lubricant seal chamber, andby conducting said part of said flow of lubricant from the lubricant circulation line into the bottom of said at least one lubricant seal chamber in the first line part.

5. The method according to claim 1wherein connecting the first line part in fluid connection with a bottom of the bearing arrangement, and connecting the first line part in fluid connection with a bottom of said at least one lubricant seal chamber, andby conducting said part of said flow of lubricant from the bottom of the bearing arrangement into the bottom of said at least one lubricant seal chamber in the first line part.

6. The method according to claim 1wherein providing the second line part by means an equalizing channel between said at least one lubricant seal chamber and the bearing arrangement, andby conducting said part of said flow of lubricant from said at least one lubricant seal chamber to the bearing arrangement in the second line part.

7. The method according to claim 1wherein connecting the second line part in fluid connection with a top of said at least one lubricant seal chamber and in fluid connection with the bearing arrangement, andby conducting said part of said flow of lubricant from the top of said at least one lubricant seal chamber into the bearing arrangement in the second line part.

8. The method according to claim 1wherein connecting the second line part in fluid connection with a bottom of said at least one lubricant seal chamber and in fluid connection with the lubricant circulation line at a point downstream of the bearing arrangement and upstream of the lubricant circulator, andby conducting said part of said flow of lubricant from the bottom of said at least one lubricant seal chamber into the lubricant circulation line in the second line part.

9. An arrangement for sealing a propeller shaft of a marine vessel, wherein the propeller shaft is arranged at a pod that is suspended at a hull of the marine vessel,wherein a propeller is attached to a driving end of the propeller shaft, wherein the driving end projects out of the pod,wherein the propeller shaft is rotatably supported with a bearing arrangement inside the pod,wherein at least two seal rings are provided axially spaced apart from each other in the axial direction of the propeller shaft and engaging the outer circumference of the propeller shaft such that at least one lubricant seal chamber is delimited between adjacent seal rings, andwherein the bearing arrangement comprises a lubrication arrangement comprising a lubricant circulation line for conducting lubricant to said bearing arrangement and for conducting lubricant from said bearing arrangement, and a lubricant circulator configured to create a flow of lubricant in the lubricant circulation line and in the bearing arrangement,wherein the lubrication arrangement includes an additional lubrication circulation line for conducting a part of said flow of lubricant to said at least one lubricant seal chamber and for conducting said part of said flow of lubricant from said at least one lubricant seal chamber, andby the lubrication arrangement being additionally configured to create a flow of lubricant in the additional lubricant circulation line and in said at least one lubricant seal chamber.

10. The arrangement according to claim 9wherein the lubricant circulator of the lubrication arrangement being additionally configured to create a flow of lubricant in the additional lubricant circulation line and in said at least one lubricant seal chamber.

11. The arrangement according to claim 9wherein the first line part being in fluid connection with the lubricant circulation line at a point downstream of the lubricant circulator and upstream of said at least one lubricant seal chamber and in fluid connection with said at least one lubricant seal chamber, wherein the first line part being configured to conduct said part of said flow of lubricant from the lubricant circulation line to said at least one lubricant seal chamber.

12. The arrangement according to claim 9wherein the first line part being in fluid connection with the lubricant circulation line at a point downstream of the lubricant circulator and upstream of said at least one lubricant seal chamber and in fluid connection with a bottom of said at least one lubricant seal chamber, wherein the first line part being configured to conduct said part of said flow of lubricant from the lubricant circulation line into the bottom of said at least one lubricant seal chamber.

13. The arrangement according to claim 9wherein the first line part being in fluid connection with a bottom of the bearing arrangement, and in fluid connection with a bottom of said at least one lubricant seal chamber, wherein the first line part being configured to conduct said part of said flow of lubricant from the bottom of the bearing arrangement into the bottom of said at least one lubricant seal chamber.

14. The arrangement according to claim 9wherein the second line part being formed by an equalizing channel between said at least one lubricant seal chamber and the bearing arrangement, wherein the first line part being configured to conduct said part of said flow of lubricant from said at least one lubricant seal chamber to the bearing arrangement.

15. The arrangement according claim 9wherein the second line part being in fluid connection with a top of said at least one lubricant seal chamber and in fluid connection with the bearing arrangement, wherein the second line part being configured to conduct said part of said flow of lubricant from the top of said at least one lubricant seal chamber into the bearing arrangement.

16. The arrangement according to claim 9wherein the second line part being in fluid connection with a bottom of said at least one lubricant seal chamber and in fluid connection with the lubricant circulation line at a point downstream of the bearing arrangement and upstream of the lubricant circulator, wherein the second line part being configured to conduct said part of said flow of lubricant from the bottom of said at least one lubricant seal chamber into the lubricant circulation line.

17. The method according to claim 2wherein connecting the first line part in fluid connection with the lubricant circulation line at a point downstream of the lubricant circulator and upstream of said at least one lubricant seal chamber, and connecting the first line part in fluid connection with said at least one lubricant seal chamber, andby conducting said part of said flow of lubricant from the lubricant circulation line to said at least one lubricant seal chamber in the first line part.

18. The method according to claim 2wherein connecting the first line part in fluid connection with the lubricant circulation line at a point downstream of the lubricant circulator and upstream of said at least one lubricant seal chamber, and connecting the first line part in fluid connection with a bottom of said at least one lubricant seal chamber, andby conducting said part of said flow of lubricant from the lubricant circulation line into the bottom of said at least one lubricant seal chamber in the first line part.

19. The method according to claim 2wherein connecting the first line part in fluid connection with a bottom of the bearing arrangement, and connecting the first line part in fluid connection with a bottom of said at least one lubricant seal chamber, andby conducting said part of said flow of lubricant from the bottom of the bearing arrangement into the bottom of said at least one lubricant seal chamber in the first line part.

20. The method according to claim 2wherein providing the second line part by means an equalizing channel between said at least one lubricant seal chamber and the bearing arrangement, andby conducting said part of said flow of lubricant from said at least one lubricant seal chamber to the bearing arrangement in the second line part.