Ship applied with air lubircation system and compressed air supply method thereof
Patent Information
- Authority / Receiving Office
- KR · KR
- Patent Type
- Patents
- Current Assignee / Owner
- HANWHA OCEAN CO LTD (KR)
- Filing Date
- 2020-11-16
- Publication Date
- 2026-08-03
Smart Images
Figure R1020200152949_ABST
Abstract
Description
Technology Field
[0001] The present invention relates to an air lubrication system for a ship, and more specifically, to a ship equipped with an air lubrication system capable of reducing frictional resistance of the ship by forming air bubbles on the surface of the bottom of the hull, and a method for supplying compressed air to said ship. Background Technology
[0002] Generally, frictional resistance acts between the hull and the seawater during the operation of a ship, and as the surface area in contact with the seawater increases with the size of the ship, the propulsion force can be significantly reduced, leading to an increase in fuel costs.
[0003] Therefore, various efforts are being made to reduce fuel costs during ship operation, and it is known that injecting compressed air onto the surface of the ship's bottom to lay air bubbles like a carpet between the hull and the seawater is very effective in reducing frictional resistance.
[0004] As such, a system that reduces the frictional resistance of a hull by forming an air layer through air bubbles on the surface of the ship's bottom is called an Air Lubircation System (ALS).
[0005] FIG. 1 is a schematic diagram illustrating an air lubrication system of a ship according to the prior art, and FIG. 2 is a diagram illustrating the stern of a ship according to the prior art.
[0006] Referring to FIG. 1, in the prior art, a separate compression unit (11) for an air lubrication system is installed on the bow side of the ship, and the compression unit (11) is connected to a plurality of nozzles (not shown) formed on the bottom surface of the ship by an air supply line (12) to spray compressed air onto the bottom surface of the ship.
[0007] An air lubrication system for a ship according to the prior art can have the effect of reducing frictional resistance of the hull and improving the propulsion of the ship by injecting compressed air onto the bottom of the bow of the ship and allowing air bubbles to spread toward the stern along the flow of seawater during the operation of the ship.
[0008] However, the air lubrication system of a ship according to the prior art uses only two compressors, specifically a compressor unit (11) additionally installed in the internal space on the bow side of the hull to supply compressed air to the bottom surface of the hull, which generates about 5,500 m³ of compressed air per hour and consumes 420 kW of power. Since power is consumed due to the continuous operation of large-capacity compressors to the extent that the amount of power saved by forming air bubbles on the bottom surface of the hull and improving the propulsion of the ship is reduced, it may be inefficient in terms of energy saving.
[0009] Meanwhile, ships such as LNG carriers (LNGCs) or LNG regasification vessels (LNG RVs) are equipped with a seawater cooling system for cooling various equipment installed on the hull. As shown in FIG. 2, a seawater pump (24) is installed on a cooling line (23) connecting a sea chest (21) provided at the stern and a cooler (22). Seawater is supplied to the cooler (22) through the seawater pump (24), and the cooler (22) cools the fresh water using seawater as a refrigerant and supplies the cooled fresh water to various equipment that requires cooling.
[0010] However, when an air lubrication system is applied to such a ship, air bubbles may be introduced into the sea chest (21) provided at the stern of the hull, and the cavitation caused by the air bubbles may have an adverse effect on the cooling system, which is one of the systems that plays a central role in the ship.
[0011] Specifically, if air bubbles are introduced into the seawater pump (24) along with seawater, the flow rate and pressure of the seawater pump (24) may drop, which may cause the seawater pump (24) to malfunction or break, and as a result, it may be difficult to supply seawater smoothly to the cooler (22).
[0012] In order to solve this, in the prior art, a separate discharge line (25) extending from the sea chest (21) provided at the stern to the upper deck of the hull is installed to discharge the air inside the sea chest. However, the discharge line (25) requires the application of a large pipe, and due to fluctuations in the air bubbles sprayed on the bottom surface of the hull, additional installation of the discharge line (25) is required due to the same problem even after the ship is built, which not only increases the volume of piping for the ship but also makes it uncertain in terms of its effectiveness, so improvement is required.
[0013] The aforementioned technical configuration is provided as background technology to aid in understanding the present invention and does not constitute prior art widely known in the technical field to which the present invention belongs. Prior art literature
[0014] Republic of Korea Published Patent Application No. 10-2015-0111429 "Resistance Reduction Device for Ships" Republic of Korea Registered Patent Application No. 10-1679491 "Air Lubrication System" The problem to be solved
[0015] In addition to the aforementioned air lubrication system and cooling system, such vessels may be further equipped with a High Expansion Foam System, which generates foam and supplies it into the Engine Room (ER) when a fire occurs inside the Engine Room (ER), thereby suppressing or preventing various fires that may occur inside the Engine Room (ER) by cutting off the oxygen supply.
[0016] In ships according to the prior art, seawater is supplied to the firefighting system using a fire pump (not shown) installed in the pump room (FWD Pump room) inside the bow hull, specifically on the bow side. However, a large-capacity fire pump is required to generate a sufficient amount of foam, and when a large-capacity fire pump is used, there is always a risk of various safety accidents occurring due to unnecessary high pressure during the process of using the fire pump for deck cleaning or other purposes.
[0017] In addition, in order to connect the fire pump installed at the bow and the fire system located at the stern, a pipe of approximately 300 to 400 meters must be extended from the fire pump to the fire system from the bow to the stern. However, due to multiple cargo tanks installed in the approximately central part of the hull and cofferdams located at the bow and stern of each of the multiple cargo tanks, many constraints may arise in connecting the fire pump and the fire system.
[0018] To solve this, in the prior art, as shown in FIG. 2, a separate seawater storage unit (31) and a seawater supply pump (33) are installed to supply seawater to the fire extinguishing system from the bottom of the steering gear room (SG) provided at the stern side, and accordingly, the volume of piping can be reduced through the optimization of the pump capacity and the seawater supply line (32).
[0019] Meanwhile, the draft when cargo is loaded (laden draft) is generally 11.5m, and the draft in the ballast condition after unloading the cargo is about 9.4m, whereas in the prior art, due to the structural characteristics of the ship's hull, the seawater supply pump (33) could only be lowered to about 11m from the bottom of the hull, and as a result, the process of supplying seawater to the fire extinguishing system may be delayed significantly.
[0020] To elaborate, the standards for firefighting equipment on ships, or classification societies, require that the firefighting system be supplied with seawater for one minute, be able to suppress a fire in the engine room for 10 minutes, and be capable of five consecutive firefighting operations.
[0021] The present invention aims to provide a ship equipped with an air lubrication system capable of reducing frictional resistance of the ship by injecting compressed air onto the surface of the ship's bottom, and a method for controlling the supply of compressed air to the ship.
[0022] Furthermore, another objective is to provide a ship equipped with an air lubrication system and a method for supplying compressed air to the ship, which can satisfy classification society requirements by preventing failure or damage to the seawater cooling pump due to air bubbles in a ship equipped with an air lubrication system and solving the problem of delayed seawater supply to the fire extinguishing system for fire suppression. means of solving the problem
[0023] According to one aspect of the present invention, a vessel equipped with an air lubrication system for reducing frictional resistance of a hull by forming an air bubble on the bottom surface of the hull may be provided, comprising: an ALS compression unit installed in the internal space on the bow side of the hull and a plurality of nozzles formed on the bottom surface of the hull to spray compressed air onto the bottom surface of the hull; an ALS air chamber installed on the compressed air injection line to store compressed air; a compressed air generation unit installed inside an engine room provided on the stern side of the hull to generate compressed air for combustion of an engine; and a compressed air supply line connecting the compressed air generation unit and the ALS air chamber to supply the compressed air generated by the compressed air generation unit to the ALS air chamber.
[0024] It may further include an eductor installed at the rear end of the ALS air chamber on the above compressed air injection line to draw in air inside the bow side hull and provide a larger amount of air to the bottom surface of the hull along with the compressed air stored in the ALS air chamber.
[0025] In addition, it may further include a regulator installed upstream of the inductor on the compressed air injection line to regulate the pressure of the compressed air supplied to the inductor.
[0026] Additionally, it may further include a bypass line installed on the compressed air injection line, branching off from the upstream end of the regulator to bypass the regulator; and opening and closing valves installed respectively on the upstream end of the regulator and on the bypass line on the compressed air injection line.
[0027] In addition, the above ALS compression can be composed of three compressors that have a compressed air flow rate of 3,700 m³ and consume 160 kW of power.
[0028] Additionally, it may further include an auxiliary injection line that branches off from the compressed air injection line between the ALS air chamber and the ALS compression section, bypasses the eductor, and rejoins the compressed air injection line; and a control valve installed on the compressed air injection line between the eductor and the point where the auxiliary injection line joins.
[0029] Additionally, the above-mentioned compressed air generating unit may include a first compressor installed inside the engine room and used to control the supply of compressed air to the engine during the operation of the engine; and a first compressed air reservoir connected to the first compressor by a first storage line and storing the compressed air generated by the first compressor.
[0030] In addition, the compressed air supply line can be branched from the first storage line and connected to the ALS air chamber.
[0031] Additionally, the above-mentioned compressed air generating unit may further include: a second compressor provided separately from the first compressor inside the engine room and used during the initial operation of the engine; a second compressed air reservoir connected to the second compressor by a second storage line and storing compressed air generated by the second compressor; and an auxiliary supply line branched from the second storage line and connected to the compressed air supply line.
[0032] Additionally, the compressed air generating unit may further include a first control valve installed in close proximity to the first compressor on the compressed air supply line and controlled to supply the compressed air generated from the first compressor only to the first compressed air reservoir or to the ALS air chamber together with the first compressed air reservoir; and a second control valve installed on the auxiliary supply line and controlled to supply the compressed air generated from the second compressor only to the second compressed air reservoir or to the ALS air chamber together with the second compressed air reservoir.
[0033] In addition, it may further include a pressure measuring sensor for measuring the pressure inside the ALS air chamber.
[0034] In addition, it may further include a backflow prevention valve installed on the compressed air supply line to prevent backflow of compressed air supplied from the compressed air generating unit to the ALS air chamber.
[0035] Additionally, it may further include a stern sea chest provided on the stern side of the hull; a vent line for discharging air bubbles flowing into the stern sea chest to the outside of the hull; and an ejector installed on the vent line and generating negative pressure using compressed air generated from the compressed air generating unit.
[0036] In addition, a seawater storage unit provided in the lower part of the steering gear room of the hull (i.e., AP tank) separately from the stern sea chest;
[0037] It may further include a seawater supply pump installed on a seawater supply line connected to the seawater storage unit and for extinguishing a fire in a living area or engine room by mixing foam with the seawater stored in the seawater storage unit; and a suction line branched from the seawater supply line between the seawater storage unit and the seawater supply pump and connected to the ejector to suction air within the seawater supply line.
[0038] In addition, it may further include a control unit that controls the supply of compressed air from the above-mentioned compressed air generating unit.
[0039] According to another aspect of the present invention, a method for supplying compressed air to a ship equipped with an air lubrication system may be provided, comprising the steps of: supplying compressed air generated in the compressed air generating unit to the ALS air chamber through the compressed air supply line; and injecting the compressed air stored in the ALS air chamber through the compressed air injection line onto the surface of the bottom of the hull.
[0040] In the step of injecting compressed air onto the bottom surface of the hull, if all the compressed air stored in the ALS air chamber is used or is insufficient, the ALS compressor can be operated and the compressed air generated in the ALS compressor can be supplied to the compressed air injection line through a separate auxiliary injection line that bypasses the ALS air chamber.
[0041] Additionally, in the step of injecting compressed air onto the bottom surface of the hull, if the pressure inside the ALS air chamber decreases, the method may include the step of supplying the compressed air stored in the ALS air chamber to the bottom surface of the hull by bypassing a regulator provided at the rear end of the ALS air chamber.
[0042] In addition, in the step of supplying compressed air to the ALS air chamber, the compressed air generating unit can be controlled through a separate control unit to enable the selective or simultaneous use of a mode in which air bubbles flowing into the stern sea chest provided on the stern side of the hull are discharged to the outside of the hull to remove them, and a mode in which air is sucked into the seawater supply line connecting the seawater storage unit and the seawater supply pump provided at the bottom of the steering gear room of the hull.
[0043] In addition, in a mode for removing air bubbles entering the stern sea chest by discharging them to the outside of the hull, compressed air generated from the compressed air generating unit may be used to provide negative pressure on the vent line through an ejector installed on the vent line of the stern sea chest.
[0044] In addition, in the mode of inhaling air within the seawater supply line, negative pressure can be provided to the upstream side of the seawater supply pump through a suction line that branches off from the seawater supply line between the seawater storage unit and the seawater supply pump and is connected to the ejector. Effects of the invention
[0045] The present invention can effectively reduce the frictional resistance of a ship by forming an air layer through air bubbles on the surface of the ship's bottom by installing an ALS air chamber on a compressed air injection line and supplying compressed air to the ALS air chamber using a pre-installed compressed air generator in the engine room, as well as have the effect of minimizing power consumption caused by the operation of the air lubrication system.
[0046] Furthermore, in ships equipped with an air lubrication system, it is possible to prevent failure or damage to the seawater cooling pump caused by air bubbles, and at the same time, solve the problem of delayed seawater supply to the fire suppression system for fire suppression, thereby satisfying classification society requirements. Brief explanation of the drawing
[0047] FIG. 1 is a schematic drawing illustrating the bow of a ship according to the prior art. FIG. 2 is a schematic drawing illustrating the stern of a ship according to the prior art. FIG. 3 is a schematic diagram illustrating a ship to which an air lubrication system according to one embodiment of the present invention is applied. Figure 4 is an enlarged view of the bow of the ship shown in Figure 3. Figure 5 is an enlarged view of the stern of Figure 4. Specific details for implementing the invention
[0048] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0049] First, it should be noted that when adding reference numerals to the components of each drawing, the same components are to have the same numeral whenever possible, even if they are shown on different drawings.
[0050] In describing the present invention, if it is determined that a detailed description of related known components or functions may obscure the essence of the invention, such detailed description is omitted.
[0051] In addition, while preferred embodiments of the present invention will be described below, it is understood that the technical concept of the present invention is not limited thereto and can be modified and implemented in various ways by those skilled in the art.
[0052] FIG. 3 is a schematic drawing of a ship to which an air lubrication system according to one embodiment of the present invention is applied, FIG. 4 is an enlarged drawing of the bow of the ship shown in FIG. 3, and FIG. 5 is an enlarged drawing of the stern of FIG. 4.
[0053] In describing the present invention with reference to FIG. 3, the side (left) where the propulsion device (not labeled) is provided is the stern direction of the ship, and the opposite side (right) is the bow direction.
[0054] In addition, as shown in FIG. 3, the vessel of the present embodiment may be provided with a plurality of cargo tanks (CT) enclosed by a barrier (not shown) inside the hull, and a cofferdam (CD) disposed in the spaced-out space between the plurality of cargo tanks (CT).
[0055] Here, depending on whether the cargo load acts directly on the cargo tank (CT), a membrane type or an independent tank type may be used, and in the case of the membrane type, insulation material may be filled inside the cargo tank (CT) to have a secondary barrier structure.
[0056] The cofferdam (CD) is a space that forms an independent bulkhead between multiple cargo tanks (CT). Although not shown in the drawing, multiple gas supply lines for supplying inert gases, such as nitrogen, to the interior of each of the multiple cargo tanks (CT) may be installed inside the cofferdam (CD).
[0057] Meanwhile, regarding a vessel having the above-described configuration, as previously mentioned, frictional resistance from seawater acts on the hull submerged in water while the vessel is in operation, and as the surface area in contact with seawater increases with larger vessels, the propulsion force may be significantly reduced, which may lead to an increase in fuel costs.
[0058] The vessel of the present embodiment may be equipped with (or applied to) an air lubrication system (ALS) for reducing frictional resistance of the hull by forming air bubbles (more precisely, micro air bubbles) on the surface of the bottom of the hull.
[0059] Referring to FIGS. 3 to 5, a ship equipped with an air lubrication system according to one embodiment of the present invention may include an ALS compression unit (110) installed in the internal space on the bow side of the hull and a plurality of nozzles (not shown) formed on the bottom surface of the hull, an ALS air chamber (130) installed on the compressed air injection line (120) to store compressed air, a compressed air generating unit (160) installed inside an engine room (ER) provided on the stern side of the hull, and a compressed air supply line (170) connecting the compressed air generating unit (160) and the ALS air chamber (130).
[0060] A ship equipped with an air lubrication system according to one embodiment of the present invention installs an ALS air chamber (130) capable of storing compressed air on a compressed air injection line (120), and supplies compressed air generated from a compressed air generating unit (160) to the ALS air chamber (130) through a compressed air supply line (170), thereby minimizing the power consumption resulting from the operation of the air lubrication system of the ship equipped with the air lubrication system.
[0061] The ALS compression unit (110) can be installed in the internal space on the bow side of the hull to generate compressed air.
[0062] In this embodiment, unlike the prior art, the ALS compression unit (110) is not continuously operated to spray compressed air onto the surface of the bottom of the hull, but can perform the role of intermittently replenishing compressed air inside the ALS air chamber (130) described later.
[0063] In addition, the vessel of the present embodiment can store compressed air through the ALS air chamber (130), so that even if a compressor with a lower compressed air flow rate than conventional ones is used, it can have the effect of supplying a sufficient amount of compressed air to the surface of the bottom of the hull.
[0064] The ALS compression unit (110) in this embodiment may be composed of three compressors installed in the internal space on the bow side of the hull, having a compressed air flow rate of approximately 3,700 m³ per hour and consuming 160 kW of power.
[0065] The ALS air chamber (130) is installed on the compressed air injection line (120) and receives compressed air from the compressed air generating unit (160) described later, and can store compressed air having a predetermined pressure (maximum 30 bar).
[0066] A ship equipped with an air lubrication system according to one embodiment of the present invention may further include an air eductor (140) installed at the rear end of an ALS air chamber (130) on a compressed air injection line (120), and an air regulator (150) installed between the ALS air chamber (130) and the eductor (140), that is, at the front end of the eductor (140) on the compressed air injection line (120), to regulate the pressure of the compressed air supplied to the eductor (140).
[0067] The inductor (140) can draw in air inside the hull using high-pressure compressed air in the compressed air injection line (120) and can supply compressed air at a pressure (about 1 to 2 bar) suitable for an air lubrication system to the surface of the bottom of the hull.
[0068] A vessel equipped with an air lubrication system according to one embodiment of the present invention is provided with an inductor (140) on a compressed air injection line (120) so that when compressed air is injected onto the surface of the bottom of the hull, a larger amount of air can be provided to the surface of the bottom of the hull together with the compressed air stored in the ALS air chamber (130).
[0069] The regulator (150) can perform the function of adjusting the pressure of the compressed air supplied from the ALS air chamber (130) at the front end of the inductor (140) to match the efficiency of the inductor (140).
[0070] In this embodiment, when the pressure of the ALS air chamber (130) decreases, the efficiency of the eductor (140) also decreases. In particular, when the pressure in the ALS air chamber (130) decreases, there is a risk that a pressure drop may occur in the regulator (150) installed upstream of the eductor (140).
[0071] A vessel equipped with an air lubrication system according to one embodiment of the present invention is provided with a bypass line (121) installed on a compressed air injection line (120) and branched off from the front end of a regulator (150) to bypass the regulator (150), and an opening / closing valve (123) is installed on the compressed air injection line (120), specifically on the front end of the regulator (150) and on the bypass line (121), so that when the pressure in the ALS air chamber (130) decreases, the compressed air is supplied to the surface of the bottom of the hull without passing through the regulator (150), thereby preventing a pressure drop in the regulator (150) in advance.
[0072] Here, it may be preferable to install a pressure transmitter (131) on one side of the ALS air chamber (130) to measure the pressure of the compressed air inside the ALS air chamber (130).
[0073] In addition, the vessel of the present embodiment can supply compressed air to the bottom surface of the hull by operating the aforementioned ALS compressor (110) when all the compressed air stored in the ALS air chamber (130) is used or when there is a shortage.
[0074] When the ALS compression unit (110) is operated to supply compressed air to the bottom surface of the hull, the compressed air can be supplied through an auxiliary injection line (125) that branches off from the compressed air supply line (120) between the ALS air chamber (130) and the ALS compression unit (110) and rejoins the compressed air injection line (120) at the rear end of the eductor (140).
[0075] Here, it may be desirable to additionally install a control valve (127) between the point where the inductor (140) and the auxiliary injection line (125) merge on the compressed air injection line (120), thereby preventing backflow of compressed air and enabling a smooth supply of compressed air.
[0076] The compressed air generating unit (160) is installed inside an engine room (ER) provided on the stern side of the hull to generate compressed air for combustion of an engine (not shown). In this embodiment, the compressed air generating unit (160) is connected to the ALS air chamber (130) by a compressed air supply line (170) so that the compressed air generated in the compressed air generating unit (160) can be supplied to the ALS air chamber (130).
[0077] Here, it may be preferable to install a backflow prevention valve (171) on the compressed air supply line (170) to prevent backflow of compressed air supplied from the compressed air generating unit (160) to the ALS air chamber (130).
[0078] The compressed air generating unit (160) may include a first compressor (161) installed inside the engine room (ER) as shown in FIG. 5, and a first compressed air reservoir (Air reservoir) (163) connected to the first compressor (161) by a first storage line (162) to store compressed air generated from the first compressor (161).
[0079] The first compressor (161) is designed to generate compressed air of about 8 bar to act as a buffer to control pulsations caused by pressure changes within the engine during operation, and the number of times and the operating time of the first compressor (161) can be reduced by the first compressed air reservoir (163) which receives and stores compressed air from the first compressor (161).
[0080] The compressed air generating unit (160) of the present embodiment may further include a second compressor (164) provided separately from the first compressor (161) inside the engine room (ER), and a second compressed air reservoir (166) connected to the second compressor (164) by a second storage line (165) to store the compressed air generated from the second compressor (164).
[0081] The second compressor (164) is used for the initial starting of the engine and can generate compressed air of about 30 bar, and the compressed air generated by the second compressor (164) can be stored in the second compressed air reservoir (166).
[0082] This second compressor (164) is rarely used for purposes other than the initial operation of the engine, and can perform the role of replenishing the compressed air inside the second compressed air reservoir (166) by an amount equal to the compressed air used for the initial operation of the engine.
[0083] Here, the compressed air supply line (170) may be branched from the first storage line (162) connecting the first compressor (161) and the first compressed air reservoir (163) and connected to the ALS air chamber (130), and the compressed air generating unit (160) may further include an auxiliary supply line (167) branched from the second storage line (165) connecting the second compressor (164) and the second compressed air reservoir (166) and connected to the compressed air supply line (170).
[0084] As described above, the first compressor (161) and the second compressor (164) constituting the compressed air generating unit (160) are idle equipment that is not operated except for the initial operation of the engine or buffering role, and the vessel of this embodiment can have the advantage of being able to operate the air lubrication system by utilizing such idle equipment.
[0085] Additionally, a first control valve (173) may be further provided on the compressed air supply line (170) in close proximity to the first compressor (161), and a second control valve (167a) may be provided on the auxiliary supply line (167). A vessel equipped with an air lubrication system according to one embodiment of the present invention may further include a controller (not shown) that controls the supply of compressed air generated in the compressed air generating unit (160).
[0086] The control unit of the present embodiment is connected to the first control valve (173) and can control the supply of compressed air generated in the first compressor (161) to the first compressed air reservoir (163) only, or to the ALS air chamber (130) together with the first compressed air reservoir (163).
[0087] Additionally, the control unit may be connected to the second control valve (167a) to control the supply of compressed air generated in the second compressor (164) to the second compressed air reservoir (166) only, or to the ALS air chamber (130) together with the second compressed air reservoir (166).
[0088] In this embodiment, the ALS air chamber (130) can store compressed air up to 30 bar inside, as described above, and receives compressed air from the first compressor (161) up to 8 bar through the control unit, and receives compressed air from the second compressor (164) from 8 bar to 30 bar.
[0089] Additionally, the control unit is connected to a pressure sensor (131) provided on one side of the ALS air chamber (130) and to an opening / closing valve (123) installed at the front and bypass line (121) of the regulator (150) on the compressed air injection line (12), so that when the pressure inside the ALS air chamber (130) drops, the compressed air is supplied to the inductor (140) by bypassing the regulator (150), thereby preventing a drop in pressure of the regulator (150) in advance.
[0090] Meanwhile, a ship equipped with an air lubrication system according to one embodiment of the present invention may further be equipped with a seawater cooling system for cooling various equipment, such as an engine installed on the hull, and a high expansion foam system for suppressing or preventing various fires that may occur inside the engine room (ER).
[0091] A vessel equipped with an air lubrication system according to one embodiment of the present invention may further include a stern sea chest (210) provided on the stern side bottom of the hull, a cooler (220) installed inside the engine room (ER) to cool fresh water using seawater as a refrigerant, a seawater cooling line (230) connecting the stern sea chest (210) and the cooler (220), and a seawater cooling pump (240) installed on the seawater cooling line (230) to supply seawater to the cooler (220).
[0092] In this embodiment, the cooler (220) receives seawater from the stern sea chest (210) through a seawater cooling pump (240) installed on the seawater cooling line (230), and can supply cooled fresh water to various equipment requiring cooling by cooling the fresh water using seawater as a refrigerant.
[0093] The configuration of cooling various equipment installed on the hull using such seawater is a well-known technology, so a detailed explanation thereof will be omitted.
[0094] Meanwhile, air bubbles may be introduced into the stern sea chest (210) due to the operation of the air lubrication system, and if the air bubbles are introduced into the seawater cooling pump (240) along with the seawater, the flow rate and pressure of the seawater cooling pump (240) may be lowered, and thus the seawater cooling pump (240) may malfunction or be damaged.
[0095] A vessel equipped with an air lubrication system according to one embodiment of the present invention may further include a vent line (250) for discharging air bubbles flowing into the stern sea chest (210) to the outside of the hull, and an air ejector (260) installed on the vent line (250).
[0096] The ejector (26) is a device that generates negative pressure (or vacuum) by supplying high-pressure, high-speed air, and the higher the pressure and speed of the air supplied, the greater the intensity of the vacuum.
[0097] In this embodiment, the ejector (260) can be connected to the compressed air generating unit (160), specifically the first compressed air reservoir (163) and the second compressed air reservoir (166), through a separate connection line (270), and can generate negative pressure using the compressed air generated from the compressed air generating unit (160).
[0098] The vessel of this embodiment can fundamentally block the inflow of air bubbles into the seawater cooling system through the ejector (260).
[0099] A vessel equipped with an air lubrication system according to one embodiment of the present invention has the advantage of utilizing the aforementioned idle equipment, and can also be effective in removing air bubbles entering the stern sea chest (210) by providing negative pressure on the vent line (250).
[0100] Additionally, a vessel equipped with an air lubrication system according to one embodiment of the present invention may further include a seawater storage unit (310) provided in the lower part of the steering gear room (SG) of the hull, separate from the stern sea chest (210), and a seawater supply pump (330) installed on a seawater supply line (320) connected to the seawater storage unit (310).
[0101] In this embodiment, the seawater storage unit (310) may be located in the lower part of the steering gear room (SG), specifically in the stern tank (AP Tank) (not labeled), and the seawater supply pump (330) may be used to extinguish a fire inside the accommodation or engine room by mixing foam with the seawater stored in the seawater storage unit (310).
[0102] Here, at least part of the seawater supply line (320), particularly the line connecting the seawater storage unit (310) and the seawater supply pump (330), may be configured as a single pipe by insulating it to withstand a fire, or if it is difficult to provide it as a single pipe, it may be desirable to minimize damage caused by welding and configure it as a single pipe through butt welding or a double sleeve joint formed by creating grooves (or sleeves) on both sides and welding.
[0103] Meanwhile, as previously mentioned, the draft when cargo is loaded (laden draft) is generally 11.5m, and the draft in the ballast condition after unloading the cargo and supplying ballast water is about 9.4m, and due to the structural characteristics of the ship's hull, the seawater supply pump (330) can only be lowered to about 11m from the bottom of the hull.
[0104] According to the standards for firefighting equipment on ships or classification societies, the firefighting system must be able to supply seawater to the firefighting system for 1 minute, suppress a fire in the engine room (ER) for 10 minutes, and perform 5 consecutive firefighting operations. However, the process of supplying seawater through the seawater supply pump (330) may be delayed significantly.
[0105] To solve this, a vessel equipped with an air lubrication system according to one embodiment of the present invention may further include a suction line (340) that branches off from a seawater supply line (320) between a seawater storage unit (310) and a seawater supply pump (330) and is connected to an ejector (260).
[0106] The suction line (340) of this embodiment is connected to an ejector (260) that provides negative pressure and can perform the function of sucking air in the seawater supply line (320) so that the supply of seawater to the fire extinguishing system can be completed within 1 minute as required by the classification society in the event of a fire in the engine room (ER).
[0107] In addition, in this embodiment, the control unit can supply appropriate compressed air to the ejector (260) by controlling the compressed air generating unit (160), and the selective or simultaneous use of a mode that removes air bubbles flowing into the stern sea chest (210) by discharging them to the outside of the hull and a mode that sucks in air within the seawater supply line (320) may be possible.
[0108] In this embodiment, when the air lubrication system is operated to reduce frictional resistance during the operation of the ship, the amount of air bubbles introduced into the stern sea chest (210) may vary depending on the ship's speed.
[0109] A ship equipped with an air lubrication system according to one embodiment of the present invention is provided with a separate pressure measuring means (i.e., a pressure sensor) (not shown) connected to a control unit at the front end of a seawater cooling pump (240), and when pressure fluctuation (Fluctation) or pressure drop (Low pressure) is detected, compressed air generated from the first compressor (161) of the compressed air generating unit (160) is supplied to an ejector (260) and air bubbles inside the stern sea chest (210) are sucked in and discharged to the outside.
[0110] Even during this process, if the air bubbles inside the stern sea chest (210) are not properly discharged, that is, if pressure fluctuations are continuously detected, the control unit can supply compressed air generated from the second compressor (164) to the ejector (260) to inhale and discharge a larger amount of air bubbles.
[0111] Meanwhile, the seawater supply pump (330) provided for fire suppression within the vessel in normal operating condition can maintain a negative pressure state within the seawater supply pump (330) by supplying compressed air generated from the first compressor (161) to the ejector (260) through the control unit.
[0112] Here, when an emergency condition such as the initial operation of the engine or a fire in the engine room occurs, the control unit supplies compressed air generated from the second compressor (164) to the ejector (260), thereby filling the upstream side of the seawater supply pump (330) with seawater in a short time, and can have the advantageous effect of shortening the time for supplying seawater to the fire extinguishing system.
[0113] A ship equipped with an air lubrication system according to one embodiment of the present invention can effectively reduce frictional resistance of the ship by forming an air layer through air bubbles on the surface of the ship's bottom by installing an ALS air chamber (130) on a compressed air injection line (170) and supplying compressed air to the ALS air chamber (130) using a compressed air generating unit (160) already installed in the engine room (ER). In addition, it can have the effect of minimizing power consumption due to the operation of the air lubrication system.
[0114] Furthermore, in a ship equipped with an air lubrication system, failure or damage to the seawater cooling pump (240) caused by air bubbles can be prevented, and the problem of delayed seawater supply to the fire extinguishing system for fire suppression can be solved, thereby satisfying classification society requirements.
[0115] Hereinafter, a method for supplying compressed air to a ship to which an air lubrication system according to one embodiment of the present invention configured as above is applied will be described.
[0116] A method for supplying compressed air to a ship to which an air lubrication system according to one embodiment of the present invention is applied may include the step of supplying compressed air generated in a compressed air generating unit (160) to an ALS air chamber (130) through a compressed air supply line (170), and the step of spraying the compressed air stored in the ALS air chamber (130) onto the surface of the bottom of the hull through a compressed air injection line (120).
[0117] In the step of spraying compressed air onto the bottom surface of the hull, if all the compressed air stored in the ALS air chamber (130) is used or is insufficient, the ALS compression unit (110) can be operated and the compressed air generated in the ALS compression unit (110) can be supplied to the compressed air injection line (120) through a separate auxiliary injection line (125) that operates the ALS air chamber (130).
[0118] Additionally, in the step of spraying compressed air onto the bottom surface of the hull, if the pressure inside the ALS air chamber (130) decreases, the compressed air stored in the ALS air chamber (130) can be supplied to the bottom surface of the hull by bypassing the regulator (150) provided at the rear end of the ALS air chamber (130).
[0119] Meanwhile, a method for supplying compressed air to a ship equipped with an air lubrication system according to one embodiment of the present invention controls a compressed air generating unit (160) through a separate control unit, and the control unit supplies appropriate compressed air to an ejector (260) to enable the selective or simultaneous use of a mode in which air bubbles flowing into the stern sea chest (210) are discharged to the outside of the hull and removed, and a mode in which air is sucked into a seawater supply line (320).
[0120] In a mode for removing air bubbles entering the stern sea chest (210) by discharging them to the outside of the hull, compressed air generated from a compressed air generating unit (160) can be used to provide negative pressure on a vent line (250) connected to the stern sea chest (210).
[0121] Additionally, in a mode for sucking air into the seawater supply line (320), negative pressure can be provided to the front of the seawater supply pump (330) through a suction line (340) that branches off from the seawater supply line (320) between the seawater storage unit (310) and the seawater supply pump (330) and is connected to the ejector (260).
[0122] A vessel to which an air lubrication system according to one embodiment of the present invention is applied may be any one of a vessel including an LNGC (LNG Carrier) and an LNG RV (LNG Regasification Vessel), or a special vessel including an LNG FSRU (Floating Storage and Regasification Unit).
[0123] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications, changes, and substitutions within the scope of the essential characteristics of the present invention without departing from its nature.
[0124] Accordingly, the embodiments disclosed in this invention and the accompanying drawings are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments and the accompanying drawings.
[0125] Furthermore, the scope of protection of the present invention shall be interpreted by the claims below, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols
[0126] 110: ALS Compression Section 120: Compressed air injection line 121: Bypass line 123: Shut-off valve 125: Auxiliary injection line 127: Control valve 130: ALS Air Chamber 131: Pressure transmitter 140: Eductor 150: Regulator 160: Compressed air generation unit 161: First Compressor 162: 1st storage line 163: First compressed air reservoir (Air reservoir) 164: Second Compressor 165: 2nd storage line 166: Second compressed air reservoir 167: Auxiliary supply line 167a: Second control valve 170: Compressed air supply line 171: Check valve 173: First control valve 210: Sunmi Sea Chest 220: Cooler 230: Seawater Cooling Line 240: Seawater cooling pump 250: Vent line 260: Ejector 310: Seawater storage unit 320: Seawater supply line 330: Seawater supply pump 340: Suction line
Claims
Claim 1 A vessel equipped with an air lubrication system for reducing frictional resistance of the hull by forming air bubbles on the bottom surface of the hull, comprising: an ALS compressor installed in the internal space on the bow side of the hull; a compressed air injection line for injecting compressed air onto the bottom surface of the hull by connecting the ALS compressor and a plurality of nozzles formed on the bottom surface of the hull; an ALS air chamber installed on the compressed air injection line for storing compressed air; a compressed air generating unit consisting of an idle compressor installed inside an engine room provided on the stern side of the hull that does not operate except for the initial operation of the engine or buffering role; and a compressed air supply line connecting the compressed air generating unit and the ALS air chamber to supply compressed air generated by the compressed air generating unit to the ALS air chamber, wherein the ALS compressor is not continuously operated but intermittently replenishes compressed air inside the ALS air chamber. Claim 2 A vessel equipped with an air lubrication system according to claim 1, further comprising an eductor installed at the rear end of the ALS air chamber on the compressed air injection line to draw in air inside the bow-side hull and to provide a larger amount of air to the bottom surface of the hull together with the compressed air stored in the ALS air chamber. Claim 3 A vessel equipped with an air lubrication system according to claim 2, further comprising a regulator installed upstream of the e-ductor on the compressed air injection line to regulate the pressure of the compressed air supplied to the e-ductor. Claim 4 A vessel equipped with an air lubrication system according to claim 3, further comprising: a bypass line installed on the compressed air injection line, branching off from the upstream end of the regulator to bypass the regulator; and shut-off valves installed respectively on the upstream end of the regulator and on the bypass line on the compressed air injection line. Claim 5 In claim 1, the above ALS compression unit is a vessel equipped with an air lubrication system consisting of three compressors having a compressed air flow rate of 3,700 m³ and consuming 160 kW of power. Claim 6 A vessel equipped with an air lubrication system according to claim 2, further comprising: an auxiliary injection line branched from the compressed air injection line between the ALS air chamber and the ALS compression section, bypassing the eductor, and rejoining the compressed air injection line; and a control valve installed on the compressed air injection line between the point where the eductor and the auxiliary injection line join. Claim 7 In claim 1, the compressed air generating unit comprises: a first compressor installed inside the engine room and used to control the supply of compressed air to the engine during the operation of the engine; and a first compressed air reservoir connected to the first compressor by a first storage line and storing compressed air generated by the first compressor, wherein the compressed air supply line is branched from the first storage line and connected to the ALS air chamber, thereby applying an air lubrication system to the vessel. Claim 8 In claim 7, the above-mentioned compressed air generating unit further comprises: a second compressor provided separately from the first compressor inside the engine room and used during the initial operation of the engine; a second compressed air reservoir connected to the second compressor by a second storage line and storing compressed air generated by the second compressor; and an auxiliary supply line branched from the second storage line and connected to the compressed air supply line, wherein the air lubrication system applied to the vessel is further included. Claim 9 A vessel equipped with an air lubrication system according to claim 8, wherein the compressed air generating unit further comprises: a first control valve installed in close proximity to the first compressor on the compressed air supply line and controlled to supply the compressed air generated by the first compressor only to the first compressed air reservoir or to the ALS air chamber together with the first compressed air reservoir; and a second control valve installed on the auxiliary supply line and controlled to supply the compressed air generated by the second compressor only to the second compressed air reservoir or to the ALS air chamber together with the second compressed air reservoir. Claim 10 A vessel equipped with an air lubrication system according to claim 1, further comprising a pressure measuring sensor for measuring the pressure inside the ALS air chamber. Claim 11 A vessel equipped with an air lubrication system according to claim 1, further comprising a backflow prevention valve installed on the compressed air supply line to prevent backflow of compressed air supplied from the compressed air generating unit to the ALS air chamber. Claim 12 A vessel equipped with an air lubrication system according to claim 1, further comprising: a stern sea chest provided on the stern side of the hull; a vent line for discharging air bubbles flowing into the stern sea chest to the outside of the hull; and an ejector installed on the vent line and generating negative pressure using compressed air generated from the compressed air generating unit. Claim 13 A vessel equipped with an air lubrication system according to claim 12, further comprising: a seawater storage unit provided in the lower part of the steering gear room of the hull (i.e., AP tank) separately from the stern sea chest; a seawater supply pump installed on a seawater supply line connected to the seawater storage unit and for extinguishing a fire in the accommodation area or the engine room by mixing foam with the seawater stored in the seawater storage unit; and a suction line branched from the seawater supply line between the seawater storage unit and the seawater supply pump and connected to the ejector to suction air within the seawater supply line. Claim 14 A vessel equipped with an air lubrication system according to claim 12 or 13, further comprising a control unit for controlling the supply of compressed air to the compressed air generating unit. Claim 15 A method for supplying compressed air to a ship equipped with an air lubrication system according to claim 1, comprising: a step of supplying compressed air generated in the compressed air generating unit to the ALS air chamber through the compressed air supply line; and a step of spraying the compressed air stored in the ALS air chamber through the compressed air injection line to the surface of the bottom of the hull, wherein in the step of spraying the compressed air to the surface of the bottom of the hull, if all the compressed air stored in the ALS air chamber is used or is insufficient, the ALS compressor is activated and the compressed air generated in the ALS compressor is supplied to the compressed air injection line through a separate auxiliary injection line bypassing the ALS air chamber. Claim 16 A method for supplying compressed air to a ship equipped with an air lubrication system according to claim 15, comprising the step of, in the step of injecting compressed air onto the bottom surface of the hull, supplying the compressed air stored in the ALS air chamber to the bottom surface of the hull by bypassing a regulator provided at the rear end of the ALS air chamber when the pressure inside the ALS air chamber decreases. Claim 17 A method for supplying compressed air to a ship equipped with an air lubrication system, wherein, in the step of supplying compressed air to the ALS air chamber, the compressed air generating unit is controlled to enable the selective or simultaneous use of a mode in which air bubbles flowing into the stern sea chest provided on the stern side of the hull are discharged to the outside of the hull and removed, and a mode in which air is sucked into the seawater supply line connecting the seawater storage unit provided on the lower part of the steering gear room of the hull. Claim 18 A method for supplying compressed air to a ship equipped with an air lubrication system that utilizes compressed air generated from the compressed air generating unit to provide negative pressure on the vent line through an ejector installed on the vent line of the stern sea chest in a mode for removing air bubbles flowing into the interior of the stern sea chest by discharging them to the outside of the hull. Claim 19 A method for supplying compressed air to a ship equipped with an air lubrication system, wherein, in a mode of sucking air within the seawater supply line, negative pressure is provided to the upstream end of the seawater supply pump through a suction line branched from the seawater supply line between the seawater storage unit and the seawater supply pump and connected to the ejector.