Air lubrication system for a ship

Abstract

An air lubrication system for a marine vessel is disclosed, which is adapted to reduce the frictional resistance applied to the hull of the marine vessel during navigation thereof. The air lubrication system comprises a plurality of air chambers disposed on the bottom of the vessel, and a main air supply line adapted to supply compressed air to the plurality of air chambers, wherein at least part of the scavenge air to be supplied to the main engine is supplied to the plurality of air chambers.

Description

TECHNICAL FIELD

[0001] The present invention relates to an air lubrication system, and more particularly, to an air lubrication system for a ship, which can reduce the frictional resistance of the ship by spraying compressed air to the bottom of the ship. BACKGROUND

[0002] During sailing, a ship is generally affected by the frictional resistance between the surface of the ship body and water. Since such frictional resistance accounts for most of the resistance applied to the ship body, the reduction of the frictional resistance becomes a very important issue as the size of the ship body increases.

[0003] REFERENCE Figure 1 As an example of energy saving technology, the air lubrication technology reduces the frictional resistance by supplying air bubbles to the bottom of the ship body. Since the substantial effect of energy saving, the air lubrication technology is known to be very effective in terms of suppressing carbon dioxide emission from the ship by reducing the engine load of the ship.

[0004] Since the frictional resistance of the ship is proportional to the submerged surface area thereof, the air lubrication technology reduces the submerged surface area of the water contacting the surface of the ship body by forming an air layer on the surface of the ship body, thereby reducing the frictional resistance of the ship body.

[0005] Since the formation of the air layer is greatly affected by the movement of the ship body depending on the sailing speed of the ship and the sea conditions, it is necessary to ensure uniform supply of air to the bottom of the ship even at various sailing speeds and movements of the ship body in order to reduce the frictional resistance by stable formation of the air layer.

[0006] In addition, continuous compression and supply of air to the bottom of the ship body in order to form and maintain a stable air layer on the bottom of the ship body inevitably consumes a large amount of energy in the compressor of the compressed air. Therefore, there is a need for a solution that can save energy for the generation of compressed air used in the air lubrication system.

[0007] It should be noted that the above description is provided to understand the background of the present invention, and is not a description of the conventional art recognized in the art to which the present invention relates. SUMMARY

[0008] An object of the present invention is to provide an air lubrication system for a ship, which sprays compressed air to the surface of the bottom of the ship in order to reduce the frictional resistance generated at the time of sailing of the ship, and can reduce the power consumption in the operation of a compressor suitable for generating compressed air.

[0009] According to an aspect of the present application, an air lubrication system for a marine vessel adapted to reduce frictional resistance applied to a hull of the marine vessel during navigation of the marine vessel includes a plurality of air chambers disposed on a bottom of the marine vessel, and a main air supply line adapted to supply compressed air to the plurality of air chambers, wherein at least part of a blow-off gas to be supplied to a main engine is supplied to the plurality of air chambers.

[0010] The marine vessel can have a turbocharger that compresses the sucked air using exhaust gas discharged from the main engine, and a blow-off gas supply line connecting the turbocharger to the main engine to supply the compressed air as the blow-off gas of the main engine.

[0011] The marine vessel can further include a blow-off gas bypass line branched from the blow-off gas supply line and connected to the main air supply line.

[0012] The marine vessel can further include an air cooler disposed on the main air supply line and cooling the air supplied to the plurality of air chambers.

[0013] The blow-off gas bypass line can be disposed upstream of the air cooler on the main air supply line.

[0014] The marine vessel can further include an air compressor disposed on the main air supply line upstream of a connection point of the blow-off gas bypass line to the main air supply line and generating the compressed air, and a first valve disposed between the connection point of the blow-off gas bypass line to the main air supply line and the air compressor.

[0015] The blow-off gas supply line can have a cooler cooling the air compressed by the turbocharger and a blow-off gas receiver disposed downstream of the cooler and storing the blow-off gas.

[0016] The blow-off gas bypass line can be branched between the cooler and the blow-off gas receiver.

[0017] The marine vessel can further include a blow-off gas valve disposed on the blow-off gas bypass line and controlling supply of the blow-off gas to the main air supply line.

[0018] The blow-off gas valve can be controlled to be closed in an International Maritime Organization Tier III nitrogen oxide emission standard mode or in a low load condition of the main engine.

[0019] The marine vessel can further include an overboard discharge line branched from the main air supply line and adapted to discharge the compressed air from the marine vessel instead of supplying the compressed air to the plurality of air chambers, and a discharge valve disposed on the overboard discharge line.

[0020] According to an embodiment of the present application, an air lubrication system for a marine vessel sprays compressed air to a bottom surface in order to reduce frictional resistance during navigation of the marine vessel, and supplies at least part of a blow-off gas to a plurality of air chambers instead of supplying all of the blow-off gas to a main engine in order to reduce power consumption by reducing an operation time of an air compressor.

[0021] In addition, according to an embodiment of the present application, a scavenging valve is disposed on a scavenging bypass line branched from the scavenging supply line to open or close the scavenging bypass line as necessary, thereby protecting the main engine while minimizing inefficient operation thereof. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and other aspects, features, and advantages of the present application will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate several embodiments of the present application.

[0023] Figure 1 A schematic diagram of a typical air lubrication system for a ship.

[0024] Figure 2 A schematic diagram of an air lubrication system for a ship according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings. In the entire specification, the same components will be designated by the same reference numerals.

[0026] Figure 2 A schematic diagram of an air lubrication system for a ship according to an embodiment of the present application.

[0027] REFERENCE Figure 2 An air lubrication system for a ship according to an embodiment of the present application includes a plurality of air chambers 10 and an air supply unit 20.

[0028] The plurality of air chambers 10 can be disposed on a ship bottom and can have a plurality of air outlets (not shown) through which air is discharged to a ship bottom surface, respectively.

[0029] REFERENCE Figure 2 The air supply unit 20 can include an air compressor 21 generating compressed air, a main air supply line L1 connected to the air compressor 21 to supply the compressed air to the plurality of air chambers 10, and a first valve 22 disposed on the main air supply line L1.

[0030] The air lubrication system according to the embodiment can supply the compressed air to the plurality of air chambers 10 through the air supply unit 20, and can form an air layer on a ship bottom surface to reduce frictional resistance of a ship body through air bubbles formed thereon.

[0031] Here, in order to stably form the air layer on the ship bottom surface, the ship inevitably consumes a large amount of energy at the time of continuous operation of the air compressor 21.

[0032] Specifically, a separate air compressor is disposed inside the hull to inject compressed air to the bottom surface of the ship, and a large amount of power is required for the operation of the compressor, thereby offsetting the effect of the air lubrication system to reduce power consumption by reducing the frictional resistance applied to the hull.

[0033] That is, due to the continuous operation of a large-capacity compressor corresponding to the amount of power reduced by reducing the frictional resistance applied to the hull by forming air bubbles on the bottom surface of the ship during the navigation of the ship, a large amount of power consumption is caused, thereby causing the energy efficiency of the ship to decrease.

[0034] Reference Figure 2 The exhaust gas discharged from the main engine ME of the ship is stored in the exhaust gas receiver ER, and at least part of the exhaust gas discharged from the exhaust gas receiver ER can be supplied to the turbocharger TC.

[0035] The turbocharger TC is used to compress the sucked air using the exhaust gas discharged from the main engine ME, and the driving force of a turbine (not shown) can be generated using the pressure of the exhaust gas.

[0036] In this embodiment, the turbocharger TC can be connected to the main engine ME via the scavenge supply line L2.

[0037] The scavenge supply line L2 can be used to supply air compressed by the turbocharger TC as scavenge air of the main engine ME.

[0038] Here, since the air sucked by the turbocharger TC generates heat during compression, the scavenge supply line L2 can have a cooler C to cool the air compressed by the turbocharger TC.

[0039] In addition, a scavenge receiver SR adapted to store scavenge air can be disposed downstream of the cooler C on the scavenge supply line L2.

[0040] That is, the air compressed by the turbocharger TC can be cooled by the cooler C and supplied to the scavenge receiver SR.

[0041] The air lubrication system according to the embodiment injects compressed air to the bottom surface of the ship in order to reduce the frictional resistance during the navigation of the ship, and supplies at least part of the scavenge air to the plurality of air chambers 10 instead of the main engine ME in order to reduce power consumption by reducing the operation time of the air compressor 21.

[0042] The air lubrication system according to the embodiment can further include a scavenge bypass line L3 branched from the scavenge supply line L2 and connected to the main air supply line L1.

[0043] Preferably, the scavenge bypass line L3 is branched from the scavenge supply line L2 between the cooler C and the scavenge receiver SR disposed on the scavenge supply line L2.

[0044] The air lubrication system according to the embodiment may further include an air cooler 23 disposed on the main air supply line L1 and cooling the air supplied to the plurality of air chambers 10.

[0045] Here, the scavenging bypass line L3 is preferably located upstream of the air cooler 23 on the main air supply line L1.

[0046] Additionally, the scavenging valve 30 can be installed on the scavenging bypass line L3 to control the supply of scavenging air to the main air supply line L1.

[0047] For reference purposes, in accordance with the amendment to Article 13 of Annex VI of the International Convention for the Prevention of Pollution from Ships (MARPOL), vessels that have installed keels after January 1, 2016, must have their main engines and diesel generators meet the International Maritime Organization Tier III Nitrogen oxide emission standard (IMONOx Tier III) when operating in an emission control area (ECA).

[0048] The scavenging valve 30 can control the supply of scavenging air in IMO NOx Tier III mode or under low load conditions of the main engine ME.

[0049] Here, IMO NOx Tier III mode may mean a navigation mode that meets IMO NOx Tier III when operating in an emission control area.

[0050] According to this embodiment, the scavenging valve 30 opens or closes the scavenging bypass line L3 as needed, thereby protecting the main engine ME and minimizing inefficient operation.

[0051] like Figure 2 As shown, in the air lubrication system according to the embodiment, the air compressor 21 may be disposed (installed) upstream of the connection point between the scavenging bypass line L3 and the main air supply line L1 on the main air supply line L1, and the first valve 22 may be disposed on the main air supply line L1 between the air compressor 21 and the connection point between the scavenging bypass line L3 and the main air supply line L1.

[0052] Here, the first valve 22 can be used to control the compressed air generated in the air compressor 21 to be supplied to the multiple air chambers 10.

[0053] When scavenging air is supplied to the main air supply line L1 through the scavenging air bypass line L3, the air lubrication system according to the embodiment closes the first valve 22 to stop the operation of the air compressor 21.

[0054] In addition, when the amount of scavenging air supplied to the main air supply line L1 through the scavenging bypass line L3 is small, or when the pressure of the air supplied to the multiple air chambers 10 is low, the air lubrication system opens the first valve 22 to operate the air compressor 21, so that sufficient compressed air can be supplied to the multiple air chambers 10.

[0055] In this embodiment, taking into account the installation location of the main engine ME, the air compressor 21 may be installed in the foredeck storage, in the engine room (not shown), or on the main deck above the engine room.

[0056] The air supply unit 20 may further include a plurality of auxiliary lines SL1 connected in parallel to the main air supply line L1 and a plurality of parallel lines SL2 branching from each of the plurality of auxiliary lines SL1 and connected in parallel to the plurality of air chambers 10.

[0057] like Figure 2 As shown, multiple air chambers 10 are connected in parallel to multiple auxiliary lines LS1 to form at least one group, and each of the multiple auxiliary lines LS1 may have a flow meter 24 and a second valve 25.

[0058] The second valve 25 is used to control the flow rate of air supplied from the auxiliary line SL1 to the parallel line SL2, and can be installed downstream of the flow meter 24 on the auxiliary line SL1.

[0059] In addition, each of the multiple parallel lines SL2, such as in the multiple auxiliary lines LS1, may have a flow meter (not shown) and a third valve 26.

[0060] In this embodiment, each of the second valve 25 and the third valve 26 may include an electronically controlled valve (not shown).

[0061] The air lubrication system according to the embodiment may further include an external discharge line L4 branching from the main air supply line L1 and adapted to discharge compressed air from the hull rather than supplying compressed air to the plurality of air chambers 10, and a discharge valve 27 disposed on the external discharge line L4.

[0062] like Figure 2 As shown, the external exhaust line L4 can be located upstream of multiple air chambers 10. Preferably, the external exhaust line L4 is located downstream of the air cooler 23 on the main air supply line L1.

[0063] According to this embodiment, when the ship is at anchor or turning, the discharge valve 27 can be controlled to discharge the compressed air to the outside of the ship body, that is, to the atmosphere, instead of supplying the compressed air to the plurality of air chambers 10.

[0064] The air lubrication system according to the embodiment can reduce the frictional resistance during the sailing of the ship by injecting the compressed air to the ship bottom surface, and can reduce the power consumption by reducing the operation time of the air compressor 21 by supplying at least part of the scavenging air to the plurality of air chambers instead of supplying all of the scavenging air to the main engine ME.

[0065] In addition, the scavenging valve 30 is disposed on the scavenging bypass line branched from the scavenging supply line to open or close the scavenging bypass line as necessary, thereby not only protecting the main engine but also minimizing the inefficient operation.

[0066] While some embodiments have been described herein, it will be understood by those skilled in the art that various modifications, changes, and improvements can be made thereto without departing from the spirit and scope of the application. It is therefore intended that the above embodiments and drawings be illustrative only, and that the application is not intended to be limited thereto. The scope of the application should be limited only by the appended claims and equivalents thereof.

Claims

1. An air lubrication system for a marine vessel adapted to reduce frictional resistance applied to a hull of the marine vessel during navigation of the marine vessel, the air lubrication system comprising: a plurality of air chambers disposed on a ship bottom; and a main air supply line adapted to supply compressed air to the plurality of air chambers, wherein at least a portion of a blow-by gas to be supplied to a main engine is supplied to the plurality of air chambers, the air lubrication system further comprising: an air compressor disposed on the main air supply line upstream of a connection point of a blow-by bypass line to the main air supply line and generating compressed air; and a first valve disposed between the air compressor and the connection point of the blow-by bypass line to the main air supply line, wherein the marine vessel has a turbocharger using exhaust gas discharged from the main engine to compress drawn air and a blow-by supply line connecting the turbocharger to the main engine to supply the compressed air as a blow-by gas of the main engine, and further includes the blow-by bypass line branched from the blow-by supply line and connected to the main air supply line, wherein, when an amount of blow-by gas supplied to the main air supply line through the blow-by bypass line is small, or when a pressure of air supplied to the plurality of air chambers is low, the air lubrication system opens the first valve to operate the air compressor so that a sufficient amount of the compressed air is supplied to the plurality of air chambers through the main air supply line after being merged with the blow-by gas within the main air supply line.

2. The air lubrication system for a marine vessel according to claim 1, further comprising: an air cooler disposed on the main air supply line and cooling air supplied to the plurality of air chambers, wherein the blow-by bypass line is disposed upstream of the air cooler on the main air supply line.

3. The air lubrication system for a marine vessel according to claim 1, wherein the blow-by supply line has a cooler cooling the air compressed by the turbocharger and a blow-by receiver disposed downstream of the cooler and storing the blow-by gas, the blow-by bypass line being branched between the cooler and the blow-by receiver.

4. The air lubrication system for a marine vessel according to claim 1, further comprising: a blow-by valve disposed on the blow-by bypass line and controlling supply of the blow-by gas to the main air supply line.

5. The air lubrication system for a marine vessel according to claim 4, wherein the blow-by valve is controlled to be closed in an International Maritime Organization Tier III nitrogen oxide emission standard mode or in a low load condition of the main engine.

6. The air lubrication system for a marine vessel according to claim 1, further comprising: an overboard discharge line branched from the main air supply line and adapted to discharge the compressed air from the marine vessel instead of supplying the compressed air to the plurality of air chambers; and a discharge valve disposed on the overboard discharge line. ​ ​

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