Patent Description:
The invention also relates to a method for sealing a propeller shaft of a marine vessel with a seal arrangement comprising at least one bearing for rotatable supporting the propeller shaft, a bearing arrangement adjacent to said at least one bearing, a first lubrication arrangement comprising a first lubricant circulation line for conducting first lubricant to said bearing arrangement and for conducting first lubricant from said bearing arrangement, a first lubricant circulator configured to create a flow of first lubricant in the first lubricant circulation line and in said bearing arrangement, a shaft seal arrangement for sealing the propeller shaft against sea water, and a second lubrication arrangement comprising a second lubricant circulation line for conducting second lubricant to said shaft seal arrangement and for conducting second lubricant from said shaft seal arrangement, a second lubricant circulator configured to create a flow of second lubricant in the second lubricant circulation line and in said shaft seal arrangement.

Publication <CIT> presents a method according to the preamble of independent claim <NUM> and an arrangement according to the preamble of independent claim <NUM>.

Raising of the temperature of the lubricant in the shaft seal arrangement both consumes lubricant that is used in the shaft seal arrangement and results in wear of the shaft seal arrangement.

For prior art reference is also made to <CIT>.

The object of the invention is to provide a method and an arrangement that lowers the temperature of the temperature of the lubricant in the shaft seal arrangement and that consequently lowers the consumption of lubricant that is used in the shaft seal arrangement and that consequently lowers the wear of the shaft seal arrangement.

The arrangement of the invention is characterized by the definitions of independent claim <NUM>.

Preferred embodiments of the arrangement are defined in the dependent claims <NUM> to <NUM>.

The method of the invention is correspondingly characterized by the definitions of independent claim <NUM>.

Preferred embodiments of the method are defined in the dependent claims <NUM> to <NUM>.

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

First the arrangement for sealing a propeller shaft <NUM> of a marine vessel (not illustrated in the figures) and some embodiments and variants will be described in greater detail.

The propeller shaft <NUM> can be arranged at a hull <NUM> of a marine vessel such as at a ship or at a propulsion unit18 such as at an azimuthing podded propulsor that is arranged at a hull <NUM> of a marine vessel such as at a ship, as illustrated in <FIG>.

If the propeller shaft <NUM> is arranged at a hull <NUM> of a marine vessel, the propeller shaft has a first portion (not illustrated) that penetrates out of the hull <NUM> of the marine vessel into sea water when the marine vessel floats in sea water and to which first portion at least one propeller <NUM> is attached and a second portion (not illustrated) that is within the hull <NUM> of the marine vessel and to which second portion a drive means for rotating the propeller shaft <NUM> is functionally connected.

If the propeller shaft <NUM> is arranged at a propulsion unit <NUM> that is arranged hull <NUM> of a marine vessel, the propeller shaft has a first portion that penetrates out of a shell structure of the propulsion unit <NUM> into sea water when the marine vessel floats in sea water and to which first portion at least one propeller <NUM> is attached and a second portion that is within the shell structure of the propulsion unit <NUM> and to which second portion a drive means for rotating the propeller shaft <NUM> is functionally connected.

The propeller shaft <NUM> is rotatable supported with at least one bearing <NUM>.

The arrangement comprises a bearing arrangement <NUM> adjacent to said at least one bearing <NUM>. The bearing arrangement <NUM> can comprises a bearing housing (not marked with a reference number) encapsulating said at least one bearing <NUM>.

The arrangement comprises a first lubrication arrangement <NUM> comprising a first lubricant circulation line <NUM> for conducting first lubricant (not illustrated in the figures) to said bearing arrangement <NUM> and for conducting first lubricant from said bearing arrangement <NUM>, and a first lubricant circulator <NUM> configured to create a flow of first lubricant in the first lubricant circulation line and in said bearing arrangement <NUM>. If the bearing <NUM> arrangement comprises a bearing housing <NUM> encapsulating said at least one bearing <NUM>, the first lubricant circulation line <NUM> for conducting first lubricant to said bearing arrangement <NUM> and for conducting first lubricant from said bearing arrangement can be configured to conduct first lubricant into said bearing housing and be configured to conduct first lubricant from said bearing housing and the first lubricant circulator <NUM> configured to create a flow of first lubricant in the first lubricant circulation line and in said bearing arrangement <NUM> can be configured to create a flow of lubricant in said bearing housing.

The arrangement comprises a shaft seal arrangement <NUM> for sealing the propeller shaft <NUM> against sea water.

The arrangement comprises a second lubrication arrangement <NUM> comprising a second lubricant circulation line <NUM> for conducting second lubricant (not illustrated in the figures) to said shaft seal arrangement <NUM> and for conducting second lubricant from said shaft seal arrangement <NUM>, and a second lubricant circulator <NUM> configured to create a flow of second lubricant in the second lubricant circulation line <NUM> and in said shaft seal arrangement <NUM>.

The arrangement comprises a first heat exchanger <NUM> in thermal contact with the first lubricant circulation line <NUM> and in thermal contact with the second lubricant circulation line <NUM> for transferring thermal energy between first lubricant flowing in the first lubricant circulation line <NUM> and second lubricant flowing in the second lubricant circulation line <NUM>.

In some embodiments and variants of the arrangement, the first lubricant circulator <NUM> is a first pump.

The outer circumference of the propeller shaft <NUM> can have a first liner <NUM> at the bearing arrangement <NUM>.

The shaft seal arrangement <NUM> can in some embodiments and variants of the arrangement comprise a plurality a plurality of seal rings <NUM> axially spaced apart from each other and engaging the outer circumference of the propeller shaft <NUM> such that at least one lubricant seal chamber <NUM> is delimited between adjacent seal rings <NUM> and the outer circumference of the propeller shaft <NUM>. In such embodiments and variants of the arrangement, the second lubricant circulation line <NUM> for conducting second lubricant to said shaft seal arrangement <NUM> and for conducting second lubricant from said shaft seal arrangement <NUM> is configured to conduct second lubricant to said at least one lubricant seal chamber <NUM> and is configured to conduct second lubricant from said at least one lubricant seal chamber <NUM>. In such embodiments and variants of the arrangement, the second lubricant circulator <NUM> configured to create a flow of second lubricant in the second lubricant circulation line <NUM> and in said shaft seal arrangement <NUM> is configured to create a flow of second lubricant in the second lubricant circulation line <NUM> and in said at least one lubricant seal chamber <NUM>. In such embodiments and variants of the arrangement, at least one of the seal rings <NUM> can comprise second seal lips.

In some embodiments and variants of the arrangement, the second lubricant circulator <NUM> is a second pump.

The outer circumference of the propeller shaft <NUM> can have a second liner <NUM> at the shaft seal arrangement <NUM>.

First lubricant flowing in the first lubricant circulation line <NUM> is preferably, but not necessarily, prevented from mixing with second lubricant flowing in the second lubricant circulation line <NUM> in the first heat exchanger <NUM>.

This allows to use as the first lubricant a lubricant that has a composition that is different from the composition of the second lubricant.

First lubricant flowing in the first lubricant circulation line <NUM> is preferably, but not necessarily, prevented from flowing into the second lubricant circulation line <NUM> in the first heat exchanger <NUM>.

Second lubricant flowing in the second lubricant circulation line <NUM> is preferably, but not necessarily, prevented from flowing into the first lubricant circulation line <NUM> in the first heat exchanger <NUM>.

This allows to use as the first lubricant a lubricant that has a composition that is different from the composition of the second lubricant. The purity requirement for the first lubricant for the bearing <NUM> is for example higher than the purity requirement for the second lubricant for the shaft seal arrangement <NUM>.

The first lubricant is preferably a lubricant that has a composition that is different from the composition of the second lubricant. The purity requirement for the first lubricant for the bearing <NUM> is for example higher than the purity requirement for the second lubricant for the shaft seal arrangement <NUM>. The viscosity of the second lubricant that is used in the shaft seal arrangement <NUM> is also normally higher than the viscosity of the first lubricant that is used in the bearing <NUM>.

The arrangement can comprise a second heat exchanger <NUM> in thermal contact with the first lubricant circulation line <NUM>, wherein the second heat exchanger is configured to transfer thermal energy from first lubricant circulating in the first lubricant circulation line <NUM> and wherein the second heat exchanger <NUM> is provided from the first lubricant circulation line <NUM>. If the propeller shaft <NUM> is arranged at a propulsion unit <NUM> such as at an azimuthing podded propulsor that is arranged at a hull <NUM> of a marine vessel such as at a ship, the second heat exchanger <NUM> is preferably, but not necessarily, arranged within hull <NUM> of the ship, outside the propulsion unit <NUM>, as illustrated in <FIG>. This allows to use a large heat exchanger as the second heat exchanger <NUM>, because there is normally more space within the hull <NUM> of the ship than in the propulsion unit <NUM>. It is however possible to arrange the second heat exchanger <NUM> within the propulsion unit <NUM> as illustrated in <FIG>.

Next method for sealing a propeller shaft <NUM> of a marine vessel with a seal arrangement and some embodiments and variants of the method will be described in greater detail.

The propeller shaft <NUM> can be arranged at a hull <NUM> of a marine vessel such as at a ship or at a propulsion unit <NUM> such as at an azimuthing podded propulsor that is arranged at a hull <NUM> of a marine vessel such as at a ship, as illustrated in <FIG>.

In the method the propeller shaft <NUM> rotatable is supported with at least one bearing <NUM>.

In the method the propeller shaft <NUM> of the marine vessel is sealed with a seal arrangement comprising a bearing arrangement <NUM> adjacent to said at least one bearing <NUM>.

In the method the propeller shaft <NUM> of the marine vessel is sealed with a seal arrangement comprising a first lubrication arrangement <NUM> comprising a first lubricant circulation line <NUM> for conducting first lubricant to said bearing arrangement <NUM> and for conducting first lubricant from said bearing arrangement <NUM>, a first lubricant circulator <NUM> configured to create a flow of first lubricant in the first lubricant circulation line and in said bearing arrangement <NUM>.

If the bearing <NUM> arrangement comprises a bearing housing <NUM> encapsulating said at least one bearing <NUM>, the first lubricant circulation line <NUM> for conducting first lubricant to said bearing arrangement <NUM> and for conducting first lubricant from said bearing arrangement can be configured to conduct first lubricant into said bearing housing and be configured to conduct first lubricant from said bearing housing and the first lubricant circulator <NUM> configured to create a flow of first lubricant in the first lubricant circulation line and in said bearing arrangement <NUM> can be configured to create a flow of lubricant in said bearing housing.

In the method the propeller shaft <NUM> of the marine vessel is sealed with a seal arrangement comprising a shaft seal arrangement <NUM> for sealing the propeller shaft <NUM> against sea water.

In the method the propeller shaft <NUM> of the marine vessel is sealed with a seal arrangement comprising a second lubrication arrangement <NUM> comprising a second lubricant circulation line <NUM> for conducting second lubricant to said shaft seal arrangement <NUM> and for conducting second lubricant from said shaft seal arrangement <NUM>, a second lubricant circulator <NUM> configured to create a flow of second lubricant in the second lubricant circulation line <NUM> and in said shaft seal arrangement <NUM>.

The method comprises providing a first heat exchanger <NUM> in thermal contact with the first lubricant circulation line <NUM> and in thermal contact with the second lubricant circulation line <NUM>.

The method comprises transferring thermal energy between first lubricant flowing in the first lubricant circulation line <NUM> and second lubricant flowing in the second lubricant circulation line <NUM> by means of the first heat exchanger <NUM>.

This allows to use as the first lubricant a lubricant that has a composition that is different from the composition of the second lubricant. The purity requirement for the first lubricant for the bearing <NUM> is for example higher than the purity requirement for the second lubricant for the shaft seal arrangement <NUM>. The viscosity of the second lubricant that is used in the shaft seal arrangement <NUM> is also normally higher than the viscosity of the first lubricant that is used in the bearing <NUM>.

The method comprises preferably, but not necessarily, preventing first lubricant flowing in the first lubricant circulation line <NUM> from mixing with second lubricant flowing in the second lubricant circulation line <NUM> in the first heat exchanger <NUM>.

The method comprises preferably, but not necessarily, preventing first lubricant flowing in the first lubricant circulation line <NUM> from flowing into the second lubricant circulation line <NUM> in the first heat exchanger <NUM>.

The method comprises preferably, but not necessarily, preventing second lubricant flowing in the second lubricant circulation line <NUM> from flowing into the first lubricant circulation line <NUM> in the first heat exchanger <NUM>.

The method comprises preferably, but not necessarily, using as the first lubricant a lubricant that has a composition that is different from the composition of the second lubricant.

Claim 1:
An arrangement for sealing a propeller shaft (<NUM>) of a marine vessel, the arrangement comprising
a propeller shaft (<NUM>) rotatably supported with at least one bearing (<NUM>),
a bearing arrangement (<NUM>) adjacent to said at least one bearing (<NUM>),
a first lubrication arrangement (<NUM>) comprising a first lubricant circulation line (<NUM>) for conducting first lubricant to said bearing arrangement (<NUM>) and for conducting first lubricant from said bearing arrangement (<NUM>), and a first lubricant circulator (<NUM>) configured to create a flow of first lubricant in the first lubricant circulation line and in said bearing arrangement (<NUM>),
a shaft seal arrangement (<NUM>) for sealing the propeller shaft (<NUM>) against sea water, and
a second lubrication arrangement (<NUM>) comprising a second lubricant circulation line (<NUM>) for conducting second lubricant to said shaft seal arrangement (<NUM>) and for conducting second lubricant from said shaft seal arrangement (<NUM>), and a second lubricant circulator (<NUM>) configured to create a flow of second lubricant in the second lubricant circulation line (<NUM>) and in said shaft seal arrangement (<NUM>),
characterized
by a first heat exchanger (<NUM>) in thermal contact with the first lubricant circulation line (<NUM>) and in thermal contact with the second lubricant circulation line (<NUM>) for transferring thermal energy between first lubricant flowing in the first lubricant circulation line (<NUM>) and second lubricant flowing in the second lubricant circulation line (<NUM>).