Ships

Abstract

A ship according to one embodiment of the present invention includes an equilibrium water tank provided in a hull, and a friction reduction device provided in the hull and configured to inject gas outside the hull, and one or more of the main piping and auxiliary piping of the friction reduction device are configured so that high-temperature gas generated from the friction reduction device passes through the equilibrium water tank.

Description

[Technical Field]

[0001] The present invention relates to a ship equipped with a friction reduction device, and more particularly to a ship configured to reduce damage to piping caused by high-temperature, high-pressure gas discharged from the friction reduction device. [Background technology]

[0002] A large portion of a ship's hull is submerged in seawater, so it experiences significant frictional resistance during operation. This frictional resistance accounts for approximately 80% of the total resistance of a slow-moving ship and approximately 50% of the total resistance of a fast-moving ship.

[0003] Frictional resistance on the hull is caused by the viscosity of water particles that come into contact with the hull. Therefore, if a layer of material with a specific gravity less than that of water is formed between the hull and the water to block the viscosity of the water, the frictional resistance can be significantly reduced.

[0004] Patent Documents 1 to 3 (KR2011-0050534, KR2014-0117681, KR2015-0104540) disclose technical ideas for solving the above problems. For example, Patent Documents 1 to 3 introduce a friction reduction device that injects air onto the surface of a ship's hull to minimize frictional resistance between the surface of the hull and seawater.

[0005] However, since the friction reduction device uses a compressor to generate and discharge high-pressure gas, the temperature of the discharged gas exceeds 100°C. However, such high-temperature, high-pressure gas can damage the anti-corrosion and anti-fouling paint on the piping and surrounding components that serve as the gas discharge passage.

[0006] Furthermore, there is a problem that gas and air discharged from the friction reduction device may flow into the sea chest of the ship, hindering normal operation of the ship. Therefore, there is a need to develop a technology that can reduce the phenomenon of gas and air discharged from such devices flowing into the sea chest of the ship. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a ship capable of minimizing damage to piping caused by high-temperature, high-pressure gas discharged from a friction reduction device.

[0008] Another object of the present invention is to provide a ship that can reduce the phenomenon of gas injected from a friction reduction device flowing into a sea chest. [Means for solving the problem]

[0009] To achieve the above object, one embodiment of the present invention provides a ship including an equalization water tank provided on the hull, and a friction reduction device provided on the hull and configured to inject gas outside the hull, wherein one or more of the main pipe and auxiliary pipe of the friction reduction device are configured so that high-temperature gas generated from the friction reduction device passes through the equalization water tank. [Effects of the Invention]

[0010] The present invention can reduce damage to piping caused by high-temperature, high-pressure gas discharged from a friction reduction device.

[0011] The present invention can effectively reduce the phenomenon in which gas (or air) injected into the friction reduction device flows into the sea chest.

[0012] The present invention can improve the straightness of the air injected into the friction reduction device, and can effectively reduce the frictional resistance between the hull and seawater. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a side view of a vessel according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view of the ship shown in FIG. [Figure 3]FIG. 2 is a perspective view of a main part showing the arrangement of a compressor and an equalization water tank of the ship shown in FIG. [Figure 4] FIG. 10 is a side view of a vessel according to another embodiment of the present invention. [Figure 5] FIG. 5 is a plan view of the vessel shown in FIG. 4. [Figure 6] FIG. 5 is a perspective view of a main part showing the arrangement of a compressor and an equalizing water tank of the ship shown in FIG. 4. [Figure 7] FIG. 10 is a plan view of a vessel according to still another embodiment of the present invention. [Figure 8] FIG. 8 is a perspective view of a main part of the vessel shown in FIG. 7. [Figure 9] FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. [Figure 10] FIG. 10 is a plan view of the vessel shown in FIG. 9. [Figure 11] FIG. 10 is a perspective view of a main part showing the arrangement of a compressor and an equalizing water tank of the ship shown in FIG. [Figure 12] FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. [Figure 13] FIG. 13 is a plan view of the vessel shown in FIG. 12. [Figure 14] FIG. 13 is a perspective view of a main part showing the arrangement of a compressor and an equalizing water tank of the ship shown in FIG. 12. [Figure 15] FIG. 2 is a bottom view of the vessel shown in FIG. 1. [Figure 16] FIG. 2 is a bottom view of the vessel shown in FIG. 1. [Figure 17] FIG. 10 is a bottom view of a vessel according to another embodiment of the present invention. [Figure 18] FIG. 10 is a bottom view of a vessel according to another embodiment of the present invention. [Figure 19] FIG. 3 is a perspective view of a main part of the gas injection port shown in FIG. 2. [Figure 20] FIG. 20 is a cross-sectional view taken along line AA of the gas injection port shown in FIG. [Figure 21] FIG. 10 is a cross-sectional view taken along line AA according to another embodiment of the gas jetting port. [Figure 22] FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. [Figure 23]FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. [Figure 24] FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. [Figure 25] FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. [Figure 26] FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. [Figure 27] FIG. 27 is an enlarged view of part A shown in FIG. 26. [Figure 28] FIG. 28 is a cross-sectional view of the wing member shown in FIG. [Figure 29] FIG. 27 is a configuration diagram of the friction reduction device shown in FIG. 26. [Figure 30] FIG. 27 is a bottom view of the vessel shown in FIG. 26. [Figure 31] FIG. 27 is a bottom view of the vessel shown in FIG. 26. [Figure 32] FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. [Figure 33] FIG. 33 is a plan view of the vessel shown in FIG. 32. [Figure 34] FIG. 33 is a perspective view of a main part showing the main pipe of a compressor arranged in the cofferdam shown in FIG. 32. [Figure 35] FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. [Figure 36] FIG. 36 is a detailed view showing the layout relationship between the cofferdam and the main pipe shown in FIG. 35. [Figure 37] FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. [Figure 38] This is a detailed drawing showing the relative positions of the cofferdam, balancing water tank, and main piping shown in Figure 37. [Figure 39] FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. [Figure 40] FIG. 2 is a hydraulic circuit diagram for the main components of the friction reduction device described above. [Figure 41] FIG. 10 is a hydraulic circuit diagram of a friction reduction device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, the terms referring to the components of the present invention are named taking into consideration the function of each component, and therefore should not be understood as limiting the technical components of the present invention.

[0015] Throughout the specification, when a certain component is "connected" to another component, it means that the components are not only "directly connected" but also "indirectly connected" via another component. Furthermore, unless otherwise specified, when a certain component is "included," it does not mean that the component excludes other components, but that the component may further include other components.

[0016] [Balance water tank layout] A vessel according to one embodiment will be described with reference to FIGS. 1 to 3. FIG.

[0017] The vessel 100 according to this embodiment includes a propulsion device required for operation. For example, the vessel 100 includes a propeller 120 powered by an internal combustion engine. The propeller 120 is disposed on the stern side of the hull 110. A plurality of propellers 120 may be configured. For example, the propellers 120 may be disposed on both the left and right sides of the stern of the hull 110 to improve the operating speed or operating capacity of the vessel 100.

[0018] The ship 100 includes devices for stable navigation. For example, the ship 100 includes balancing water tanks 130 and 140. The balancing water tanks 130 and 140 can be classified as a first balancing water tank 130 and a second balancing water tank 140 depending on their locations. The first balancing water tank 130 is disposed on the bow side of the hull 110 and is generally formed tall along the height direction of the hull 110. The second balancing water tank 140 is disposed on the bottom side of the hull 110 and is generally formed long along the length direction of the hull 110. The first balancing water tank 130 and the second balancing water tank 140 are disposed symmetrically about the keel of the hull 110 as shown in FIG. 2.

[0019] The vessel 100 includes a device that can minimize frictional resistance between the hull 110 and seawater or freshwater. For example, the vessel 100 includes a friction reduction device 200 configured to inject gas (or air) onto the bottom of the hull 110, preferably onto a flat surface of the bottom.

[0020] The friction reduction device 200 is disposed on the bow side of the hull 110. However, the location of the friction reduction device 200 is not limited to the bow side of the hull 110. The friction reduction device 200 includes a compressor 210, a main pipe 220, an auxiliary pipe 230, and a gas injection port 240. However, the configuration of the friction reduction device 200 is not limited to the above-mentioned elements. For example, the friction reduction device 200 may further include valves disposed in the main pipe 220 and the auxiliary pipe 230, respectively.

[0021] The compressor 210 is disposed on the bow side of the hull 110 as shown in Fig. 1. Furthermore, the compressor 210 is preferably disposed higher than the load waterline of the hull 110 for smooth generation of compressed air and operational efficiency. The compressor 210 is disposed between a pair of first balance water tanks 130 as shown in Fig. 2. However, the position of the compressor 210 is not limited to between the first balance water tanks 130. For example, the compressor 210 may be disposed closer to the bow side than the first balance water tanks 130.

[0022] The main pipe 220 is connected to the compressor 210 and guides the compressed air generated by the compressor 210 to flow toward the stern. Furthermore, the main pipe 220 passes through at least one of two first balancing water tanks 130 as shown in FIGS. 2 and 3 to prevent the compressed air generated by the compressor 210 from overheating. Therefore, the compressed air flowing through the main pipe 220 can be cooled to 93°C or less, preferably 80°C or less, before moving toward the stern. Cooling the compressed air through the main pipe 220 in this manner can prevent or mitigate damage to the anti-corrosion and anti-fouling paint formed on the main pipe 220, auxiliary pipe 230, and hull 110, caused by overheated air.

[0023] The auxiliary pipes 230 are formed by branching off from the main pipe 220. As shown in FIG. 2, the auxiliary pipes 230 may branch off at predetermined intervals along the length of the main pipe 220 and then extend toward the stern. As shown in FIG. 2, the widthwise lengths of the auxiliary pipes 230 branching off from the main pipe 220 may increase toward the stern. For example, the widthwise length of the first auxiliary pipe 230 branching off from the main pipe 220 may be smaller than the widthwise length of the second auxiliary pipe 230 branching off from the main pipe 220, and the widthwise length of the second auxiliary pipe 230 branching off from the main pipe 220 may be smaller than the widthwise length of the third auxiliary pipe 230 branching off from the main pipe 220. The inner diameter of the auxiliary pipe 230 is preferably smaller than the inner diameter of the main pipe 220 to prevent a decrease in gas injection pressure. In addition, the inner diameter of the auxiliary pipe 230 may be different depending on the branching position from the main pipe 220. For example, the inner diameter of the first auxiliary pipe 230 branching off from the main pipe 220 may be larger than the inner diameter of the second auxiliary pipe 230 branching off from the main pipe 220, which in turn may be larger than the inner diameter of the third auxiliary pipe 230 branching off from the main pipe 220. However, the inner diameters of all the auxiliary pipes 230 may be the same if necessary.

[0024] The gas injection port 240 is connected to the auxiliary pipe 230. The gas injection port 240 is configured to inject compressed air or compressed gas supplied via the auxiliary pipe 230 into seawater. Preferably, the gas injection port 240 can inject the compressed air so that the compressed air flows along the surface of the bottom of the hull 110. For this reason, it is preferable that the final discharge direction of the gas injection port 240 is approximately parallel to the bottom surface of the hull 110.

[0025] In the ship 100 configured as described above, high-temperature, high-pressure air generated from the friction reduction device 200 is cooled while passing through the balancing water tank, thereby minimizing damage to piping caused by high-temperature compressed air. Furthermore, in the ship 100 according to this embodiment, the compressed air is cooled through the balancing water tank, so a separate device for cooling the compressed air can be omitted. Therefore, the ship according to this embodiment can not only reduce construction costs but also improve the utilization rate of the interior space of the ship.

[0026] Next, a vessel according to another embodiment will be described with reference to Figures 4 to 6. For reference, in the following description, the same components as those in the above-described embodiment will be designated by the same reference numerals, and detailed description of these components will be omitted.

[0027] 4, the vessel 101 according to this embodiment includes a propeller 120 disposed at the stern of a hull 110, and a plurality of balancing water tanks 130 and 140 formed in the hull 110. Furthermore, the vessel 101 includes a friction reduction device 200.

[0028] 5 and 6, the ship 101 according to this embodiment can be distinguished from the above-described embodiments in that it includes a plurality of main pipes 220 and 222. In addition, the compressed air generated from the compressor 210 can be supplied to the gas injection ports 240 and 242 via the first main pipe 220 and the second main pipe 222. In addition, the first main pipe 220 and the second main pipe 222 can be cooled by the first balancing water tank 130 and the first balancing water tank 132, respectively.

[0029] The ship 101 configured in this manner supplies compressed air to the respective gas jet ports 240, 242 via the multiple main pipes 220, 222, thereby improving the effect of air jets in reducing friction on the hull 110. Furthermore, in the ship 101 according to this embodiment, the main pipes 220, 222 are cooled by the respective balancing water tanks 130, 132, thereby improving the cooling efficiency of the balancing water tanks 130, 132.

[0030] Next, a vessel according to yet another embodiment will be described with reference to Figures 7 and 8. For reference, in the following description, the same components as those in the above-described embodiment will be designated by the same reference numerals, and detailed description of these components will be omitted.

[0031] The ship 102 according to this embodiment is distinguished from the above-described embodiments in that it is configured with a single balancing water tank 130. Furthermore, the main pipe 220 is configured to vertically penetrate the center portion of the balancing water tank 130. For reference, this embodiment shows that one main pipe 220 vertically penetrates the balancing water tank 130, but this may be modified so that two or more main pipes 220 penetrate the balancing water tank 130 as necessary.

[0032] Next, a vessel according to yet another embodiment will be described with reference to Figures 9, 10, and 11. For reference, in the following description, the same components as those in the above-described embodiment will be designated by the same reference numerals, and a description of these components will be omitted.

[0033] The ship 103 according to this embodiment is distinguished from the above-described embodiments in the arrangement of the auxiliary pipes 220.

[0034] As shown in FIGS. 10 and 11 , the auxiliary pipe 230 passes through the second balancing water tank 140 to prevent overheating of the compressed air generated by the compressor 210. Additionally, at least a portion of the auxiliary pipe 230 branching off from the main pipe 220 may extend to the flat surface of the bottom of the ship after passing through the interior space of the second balancing water tank 140. Therefore, the compressed air flowing through the auxiliary pipe 230 can be cooled to 93°C or less, preferably 80°C or less, before moving toward the stern. Cooling the compressed air through the auxiliary pipe 230 in this manner can prevent or mitigate damage to the anti-corrosion and anti-fouling paint formed inside the main pipe 220 and the auxiliary pipe 230 caused by overheated air.

[0035] In the ship 103 configured as described above, high-temperature, high-pressure air generated from the friction reduction device 200 is cooled while passing through the balancing water tank, thereby minimizing damage to piping caused by high-temperature compressed air. Furthermore, in the ship 103 according to this embodiment, the compressed air is cooled through the balancing water tank, so a separate device for cooling the compressed air can be omitted. Therefore, the ship according to this embodiment can not only reduce construction costs but also improve the utilization rate of the interior space of the ship.

[0036] Next, a vessel according to still another embodiment will be described with reference to Figures 12, 13, and 14. For reference, in the following description, the same components as those in the above-described embodiment will be designated by the same reference numerals, and a description of these components will be omitted.

[0037] 12, the vessel 104 according to this embodiment includes a propeller 120 disposed at the stern of a hull 110, and a plurality of balancing water tanks 130 and 140 formed in the hull 110. Furthermore, the vessel 104 includes a friction reduction device 200.

[0038] 13 and 14, the ship 104 according to this embodiment can be distinguished from the above-described embodiments in that it includes a plurality of main pipes 220, 222. The ship 102 according to this embodiment can also be distinguished from the above-described embodiments in that the main pipes 220, 220 are cooled via first balance water tanks 130, 132.

[0039] Additionally, the compressed air generated from the compressor 210 may be supplied to the respective gas injection ports 240, 242 via the first main pipe 220 and the second main pipe 222. Here, the first main pipe 220 and the second main pipe 222 may be configured to pass through the first balancing water tank 130 and the first balancing water tank 132 so as to primarily cool the compressed air. Furthermore, the first auxiliary pipe 230 and the second auxiliary pipe 232 may be configured to pass through the second balancing water tanks 140, 142 so as to secondarily cool the compressed air supplied via the main pipes 220, 222.

[0040] The ship 104 configured in this manner supplies compressed air to the respective gas jet ports 240, 242 via the multiple main pipes 220, 222, thereby improving the effect of reducing friction on the hull 110 through air jets. Furthermore, in the ship 102 according to this embodiment, the main pipes 220, 222 and auxiliary pipes 230, 232 are cooled by the first equilibrium water tanks 130, 132 and second equilibrium water tanks 140, 142, respectively, so the cooling efficiency of the equilibrium water tanks 130, 132, 140, 142 can also be improved.

[0041] [Gas injection nozzle arrangement structure] The arrangement of the gas injection ports will be described with reference to FIGS.

[0042] The gas jet ports 240 may be divided into several groups. More specifically, the gas jet ports 240 may be classified sequentially from the bow side of the hull 110 into a first group of gas jet ports 241, a second group of gas jet ports 242, and a third group of gas jet ports 243. The gas jet ports 241, 242, and 243 are arranged symmetrically about the keel of the hull 110. The spacing between pairs of gas jet ports 241, 242 may gradually increase from the bow side of the hull 110 toward the stern. The gas jet ports 241, 242 constituting the first and second groups are arranged so as not to overlap with the gas jet ports 241, 242 arranged forward (based on a front view of the hull 110). However, the gas injection ports 243 constituting the third group may be arranged so as to partially overlap the gas injection ports 241, 242 constituting the first or second group.

[0043] The number of gas injection ports 241, 242, 243 may differ for each of the first to third groups. For example, the number of gas injection ports 241 constituting the first group may be less than the number of gas injection ports 242 constituting the second group, but may be greater than the number of gas injection ports 243 constituting the third group. In contrast, the number of gas injection ports 242 constituting the second group may be greater than the numbers of gas injection ports 241, 243 constituting the first and third groups.

[0044] The maximum spacing between pairs of gas injection ports 241, 242, 243 may differ for each of the first to third groups. For example, the maximum spacing W1 between gas injection ports 2414 in the first group may be smaller than the minimum spacing W2 between gas injection ports 2428 in the second group, and smaller than the minimum spacing W4 between gas injection ports 2431 in the third group. Furthermore, the maximum spacing W5 between gas injection ports 2432 in the third group may be larger than the minimum spacing W2 between gas injection ports 2428 in the second group, and smaller than the maximum spacing W3 between gas injection ports 2428 in the second group.

[0045] The distance from the forward-most gas jet port to the rearmost gas jet port in each group may be different for each group. For example, the length L1 in the hull direction from the forward-most gas jet port 2411 to the rearmost gas jet port 2414 in the first group may be smaller than the length L2 in the hull direction from the forward-most gas jet port 2421 to the rearmost gas jet port 2428 in the second group, and may be greater than the length L3 in the hull direction from the forward-most gas jet port 2431 to the rearmost gas jet port 2432 in the third group.

[0046] The distance between the rearmost gas jet port of the front group and the frontmost gas jet port of the rear group may be different. For example, the distance S1 between the rearmost gas jet port 2414 of the first group and the frontmost gas jet port 2421 of the second group may be smaller than the distance S2 between the rearmost gas jet port 2428 of the second group and the frontmost gas jet port 2431 of the third group. Furthermore, the distance between the rearmost gas jet port of the front group and the frontmost gas jet port of the rear group may be larger than the distance between the gas jet ports of each group.

[0047] The distance L4 from the bisector or keel of the hull 110 to the gas jet port 2428 located at the outermost hull may be smaller than the distance L5 from the bisector or keel of the hull 110 to the sea chest 180. Preferably, L4 / L5 may be in the range of 0.5 to 0.7. More preferably, L4 / L5 may be in the range of 0.58 to 0.68.

[0048] Furthermore, the ratio S3 / L between the keel and the distance S3 from the outermost gas jet nozzle 2428 to the sea chest 180 relative to the length L of the hull 110 should be 0.5 or less. Preferably, S3 / L should be 0.48 or less.

[0049] The above conditions are effective in reducing the phenomenon of gas or air discharged from the gas outlets 241, 242, and 243 flowing into the sea chest 180. Therefore, the ship 100 according to this embodiment can significantly reduce the failure rate of the ship 100 by reducing the frictional resistance between the hull 110 and seawater through the friction reduction device 200.

[0050] An arrangement of gas jetting ports of a vessel according to another embodiment will be described with reference to FIGS.

[0051] The vessel 105 according to this embodiment can be distinguished from the above-described embodiments in the arrangement of the gas jet nozzles.

[0052] The gas jet ports 240 may be divided into multiple groups. Specifically, the gas jet ports 240 may be classified into a first group of gas jet ports 241 and a second group of gas jet ports 242, sequentially from the bow side of the hull 110. The gas jet ports 241, 242 are arranged symmetrically around the keel of the hull 110. The spacing between pairs of gas jet ports 241 may gradually increase from the bow side toward the stern side of the hull 110. The gas jet ports 241 constituting the first group are arranged so as not to overlap with the gas jet ports 241 arranged forward. However, the gas jet ports 243 constituting the second group may be arranged so as to partially overlap with the gas jet ports 241 constituting the first group.

[0053] The number of gas injection ports 241, 242 may be different for each of the first group and the second group. For example, the number of gas injection ports 241 constituting the first group may be greater than the number of gas injection ports 242 constituting the second group.

[0054] The maximum and minimum spacing between pairs of gas injection ports 241, 242 may be different for each of the first and second groups. For example, the minimum spacing W0 between the gas injection ports 2411 in the first group is smaller than the minimum spacing W4 between the gas injection ports 2421 in the second group. The maximum spacing W3 between the gas injection ports 2412 in the first group may be larger than the minimum spacing W4 between the gas injection ports 2421 in the second group and larger than the maximum spacing W5 between the gas injection ports 2422 in the second group.

[0055] The distance from the forward-most gas jet nozzle to the rearmost gas jet nozzle in each group may be different for each group. For example, the length L1 in the hull direction from the forward-most gas jet nozzle 2411 to the rearmost gas jet nozzle 2412 in the first group may be greater than the length L3 in the hull direction from the forward-most gas jet nozzle 2421 to the rearmost gas jet nozzle 2422 in the second group.

[0056] The distance S2 between the rearmost gas jet 2412 of the first group and the forwardmost gas jet 2421 of the second group can be significant, for example, S2 can be smaller than L1 but larger than L1 / 2.

[0057] The distance L4 from the bisector or keel of the hull 110 to the gas jet port 2422 located at the outermost hull may be smaller than the distance L5 from the bisector or keel of the hull 110 to the sea chest 180. Preferably, L4 / L5 may be in the range of 0.5 to 0.7. More preferably, L4 / L5 may be in the range of 0.58 to 0.68.

[0058] Furthermore, the ratio S3 / L of the distance S3 from the gas jet nozzle 2422 located at the outermost part from the keel to the sea chest 180 to the length L of the hull 110 should be 0.5 or less. Preferably, S3 / L should be 0.48 or less.

[0059] The above conditions are effective in reducing the phenomenon of gas or air discharged from the gas outlets 241 and 242 flowing into the sea chest 180. Therefore, the ship 105 according to this embodiment can significantly reduce the failure rate of the ship 105 by reducing the frictional resistance between the hull 110 and seawater through the friction reduction device 200.

[0060] [Gas nozzle shape] The gas injection port will be described in detail with reference to FIGS.

[0061] The gas jet 240 includes a body portion 242 and a bottom portion 244 . The main body 242 is connected to the auxiliary pipe 230. An inclined surface is formed on one side of the main body 242. The inclined surface may be composed of multiple sections having different inclination angles. For example, the inclined surface may be composed of a first inclined portion 2422 having a first inclination angle θ1 and a second inclined portion 2424 having a second inclination angle θ2. The first inclination angle θ1 may be greater than the second inclination angle θ2. For example, the first inclination angle θ1 may be greater than 10 degrees, and the second inclination angle θ2 may be less than 10 degrees. The length of the section forming the first inclined portion 2422 on the inclined surface of the main body 242 may be greater than the length of the section forming the second inclined portion 2424. Furthermore, the height Nh1 of the first inclined portion 2422 on the inclined surface of the main body 242 may be greater than the height Nh2 of the second inclined portion 2424. This condition can direct the flow of high-pressure air parallel to the surface of the hull, increasing the flow velocity of the high-pressure air moving along the inclined surface of the main body portion 242.

[0062] The bottom portion 244 is formed at the lower part of the main body portion 242. The bottom portion 244 is configured to substantially close the open opening of the main body portion 242. The bottom portion 244 is formed with an exhaust port 2442 for injecting or discharging high-pressure air. In addition, the exhaust port 2442 is formed at the portion where the second inclined portion 2424 and the bottom portion 244 meet.

[0063] The gas injection port 240 configured as described above can discharge the high-pressure air flowing in through the auxiliary pipe 230 substantially parallel to the surface of the hull (flat part of the bottom of the hull) through the inclined portions 2422, 2424 and the discharge port 2442. Therefore, according to this embodiment, the friction resistance between the surface of the hull 110 and seawater via the friction reduction device 200 can be effectively reduced.

[0064] Next, other forms of the gas injection port will be described. For reference, in the following description, components that are the same as or similar to the gas injection port described above will be designated by the same reference numerals as the gas injection port described above, and detailed description of these components will be omitted. First, other forms of the gas injection port will be described with reference to FIG. 5.

[0065] The gas injection port 2402 according to this embodiment is distinguished from the above-described embodiment in that it further includes a first protrusion 246, as shown in FIG. 21 . The first protrusion 246 is formed on the bottom 244. Specifically, the first protrusion 246 may be formed at a first height h1 from the bottom 244. The first height h1 of the first protrusion 246 may be approximately the same as the height Nh2 of the second inclined portion 2424. However, the height h1 of the first protrusion 246 is not necessarily the same as the height Nh2 of the second inclined portion 2424. For example, the height h1 of the first protrusion 246 may be smaller than the height Nh2 of the second inclined portion 2424. The first protrusion 246 has an inclined surface. Specifically, one surface of the first protrusion 246 facing the second inclined portion 2424 may be formed as an inclined surface having a third inclination angle θ3. Here, the third inclination angle θ3 may be approximately the same as or similar to the second inclination angle θ2 of the second inclined portion 2424.

[0066] The gas injection port 2402 formed as described above limits the flow of high-pressure air by the second inclined portion 2424 and the second protrusion 246, thereby further increasing the flow rate of the high-pressure air, and thereby extending the effective flow of the high-pressure air discharged from the discharge port 2442.

[0067] Another embodiment of the gas injection port will be described with reference to FIG.

[0068] As shown in FIG. 6 , the gas injection port 2404 according to this embodiment is distinguished from the above-described embodiment in that it further includes a second protrusion 248. The second protrusion 248 is formed on the first protrusion 246. Specifically, the second protrusion 248 may be formed at a second height h2 from the top of the first protrusion 246. The second height h2 of the second protrusion 248 may be approximately the same as the height Nh1 of the first inclined portion 2422. However, the height h2 of the second protrusion 248 is not necessarily the same as the height Nh1 of the first inclined portion 2422. For example, the height h2 of the second protrusion 248 may be smaller than the height Nh1 of the first inclined portion 2422. The second protrusion 248 has an inclined surface. Specifically, one surface of the second protrusion 248 facing the first inclined portion 2422 may be formed as an inclined surface having a fourth inclination angle θ4. Here, the fourth inclination angle θ4 may be approximately the same as or similar to the first inclination angle θ1 of the first inclined portion 2422.

[0069] The gas injection port 2404 formed as described above limits and guides the flow of high-pressure air by the plurality of inclined portions 2422, 2424 and the plurality of protrusions 246, 248, thereby further improving the flow rate of the high-pressure air and thereby enabling the flow of high-pressure air to be sustained for a long time.

[0070] Still another embodiment of the gas injection port will be described with reference to FIG.

[0071] The gas jetting port 2408 according to this embodiment is distinguished from the above-described embodiment in that the inclined surface of the main body 242 is formed by one curved portion, as shown in Fig. 7. Additionally, the inclined surface may be formed by a first curved portion 2422 having a first radius of curvature R1.

[0072] Still another embodiment of the gas injection port will be described with reference to FIG.

[0073] 8, the gas jetting port 2406 according to this embodiment is distinguished from the above-described embodiment in that the inclined surface of the main body 242 is composed of a plurality of curved portions 2422, 2424. Additionally, the inclined surface may be composed of a first curved portion 2422 having a first radius of curvature R1 and a second curved portion 2424 having a second radius of curvature R2. Here, the first radius of curvature R1 may be smaller than the second radius of curvature R2.

[0074] With reference to FIG. 25, still another embodiment of the gas injection port will be described.

[0075] 9, the gas ejection port 2406 according to this embodiment is distinguished from the above-described embodiment in that the inclined surface of the main body 242 is composed of a curved portion 2422 and a straight portion 2424. Additionally, the inclined surface may be composed of a first curved portion 2422 having a first radius of curvature R1 and a first inclined portion 2424 having a first inclination angle θ1.

[0076] [Hull structure to prevent air bubbles from entering] A vessel according to another embodiment will be described with reference to FIGS.

[0077] The vessel 106 according to this embodiment includes a propulsion device required for operation. For example, the vessel 106 includes a propeller 120 powered by an internal combustion engine. The propeller 120 is disposed on the stern side of the hull 110. A plurality of propellers 120 may be configured. For example, the propellers 120 may be disposed on both the left and right sides of the stern of the hull 110 to improve the operating speed or operating capacity of the vessel 106.

[0078] The vessel 106 includes a configuration for allowing seawater to flow into the interior of the hull 110. For example, a sea chest 180 may be formed on the side of the hull 110. Additionally, the sea chest 180 may allow seawater to flow in so as to cool an internal combustion engine or the like disposed inside the hull 110.

[0079] The vessel 106 includes a device that can minimize frictional resistance between the hull 110 and seawater or freshwater. For example, the vessel 106 includes a friction reduction device 200 configured to inject gas (or air) onto the bottom of the hull 110, preferably onto a flat surface of the bottom.

[0080] The friction reduction device 200 is disposed on the bow side of the hull 110. However, the location of the friction reduction device 200 is not limited to the bow side of the hull 110. As shown in FIG. 26, the friction reduction device 200 includes a compressor 210 and a gas injection port 240. The compressor 210 is disposed on the bow side of the hull 110 as shown in FIG. 26. The compressor 210 is preferably disposed higher than the load waterline of the hull 110 for smooth generation of compressed air (or compressed gas) and for operational efficiency.

[0081] The hull 110 is provided with a wing member 160 to prevent gas generated by the friction reduction device 200 from flowing into the sea chest 180. The wing member 160 may be formed elongated from the bottom of the sea chest 180 toward the bow of the hull 110, as shown in FIG.

[0082] The wing member 160 may be formed to have a substantial length. For example, the length LC of the wing member 160 may be approximately the same as the distance from the sea chest 180 to the gas jet 240 closest to the sea chest 180. However, the length LC of the wing member 160 is not limited to the above-mentioned length.

[0083] The wing member 160 may be formed in a curved shape as shown in Fig. 27. As one example, the wing member 160 may be curved upward as it approaches the bow of the hull 110. As another example, the wing member 160 may extend horizontally along the bow of the hull 110, with the end portion (bow side portion) curved upward.

[0084] The wing member 160 is configured to minimize the phenomenon in which gas generated by the friction reduction device 200 rises above the load waterline of the hull 110. For example, the wing member 160 may include a downwardly bent portion 162 as shown in FIG. 28. The wing member 160 may protrude from the hull 110 by a considerable amount. For example, the protrusion size h of the wing member 160 may be selected from the range of 50 to 1000 mm.

[0085] The wing member 160 formed in this manner can concentrate the gas generated by the friction reduction device 200 below the load waterline of the hull 110, thereby maximizing the friction reduction effect of the gas from the friction reduction device 200.

[0086] 29, the friction reduction device 200 further includes a main pipe 220 and an auxiliary pipe 230. However, the configuration of the friction reduction device 200 is not limited to the above-mentioned elements. For example, the friction reduction device 200 may further include valves and the like arranged in the main pipe 220 and the auxiliary pipe 230, respectively.

[0087] The main pipe 220 is connected to the compressor 210 and guides the compressed air generated by the compressor 210 to flow toward the stern. A plurality of main pipes 220 may be provided. For example, two main pipes 220 may be provided.

[0088] The auxiliary pipes 230 are formed by branching off from the main pipe 220. As shown in FIG. 29, the auxiliary pipes 230 may branch off in the width direction at predetermined intervals along the length of the main pipe 220 and then extend toward the bottom and stern of the ship. The width direction lengths of the auxiliary pipes 230 branching off from the main pipe 220 may increase toward the stern, as shown in FIG. 29. For example, the width direction length of the first auxiliary pipe 230 branching off from the main pipe 220 may be smaller than the width direction length of the second auxiliary pipe 230 branching off from the main pipe 220, and the width direction length of the second auxiliary pipe 230 branching off from the main pipe 220 may be shorter than the width direction length of the third auxiliary pipe 230 branching off from the main pipe 220. The inner diameter of the auxiliary pipe 230 is preferably smaller than the inner diameter of the main pipe 220 to prevent a decrease in gas injection pressure. In addition, the inner diameter of the auxiliary pipe 230 may be formed differently depending on the branching position from the main pipe 220. For example, the inner diameter of the first auxiliary pipe 230 branching off from the main pipe 220 may be larger than the inner diameter of the second auxiliary pipe 230 branching off from the main pipe 220, which in turn may be larger than the inner diameter of the third auxiliary pipe 230 branching off from the main pipe 220. However, if necessary, the inner diameters of all the auxiliary pipes 230 may be formed to be the same size.

[0089] The gas jet port 240 is connected to the auxiliary pipe 230. The gas jet port 240 is configured to inject compressed air supplied via the auxiliary pipe 230 into seawater. Preferably, the gas jet port 240 can inject the compressed air so that the compressed air flows along the surface of the hull 110 (specifically, the flat part of the bottom surface). For this reason, it is preferable that the final discharge direction of the gas jet port 240 is approximately parallel to the bottom surface of the hull 110.

[0090] The arrangement of the gas injection ports will be described in detail with reference to FIGS.

[0091] The gas jet ports 240 may be divided into several groups. More specifically, the gas jet ports 240 may be classified sequentially from the bow side of the hull 110 into a first group of gas jet ports 241, a second group of gas jet ports 242, and a third group of gas jet ports 243. The gas jet ports 241, 242, and 243 are arranged symmetrically about the keel of the hull 110. The spacing between pairs of gas jet ports 241, 242 may gradually increase from the bow side of the hull 110 toward the stern. The gas jet ports 241, 242 constituting the first and second groups are arranged so as not to overlap with the gas jet ports 241, 242 arranged forward (based on a front view of the hull 110). However, the gas injection ports 243 constituting the third group may be arranged so as to partially overlap the gas injection ports 241, 242 constituting the first or second group.

[0092] The number of gas injection ports 241, 242, 243 may differ for each of the first to third groups. For example, the number of gas injection ports 241 constituting the first group may be less than the number of gas injection ports 242 constituting the second group, but may be greater than the number of gas injection ports 243 constituting the third group. In contrast, the number of gas injection ports 242 constituting the second group may be greater than the numbers of gas injection ports 241, 243 constituting the first and third groups.

[0093] The maximum spacing between pairs of gas injection ports 241, 242, 243 may differ for each of the first to third groups. For example, the maximum spacing W1 between gas injection ports 2414 in the first group may be smaller than the minimum spacing W2 between gas injection ports 2428 in the second group, and smaller than the minimum spacing W4 between gas injection ports 2431 in the third group. Furthermore, the maximum spacing W5 between gas injection ports 2432 in the third group may be larger than the minimum spacing W2 between gas injection ports 2428 in the second group, and smaller than the maximum spacing W3 between gas injection ports 2428 in the second group.

[0094] The distance from the forward-most gas jet port to the rearmost gas jet port in each group may be different for each group. For example, the length L1 in the hull direction from the forward-most gas jet port 2411 to the rearmost gas jet port 2414 in the first group may be smaller than the length L2 in the hull direction from the forward-most gas jet port 2421 to the rearmost gas jet port 2428 in the second group, and may be greater than the length L3 in the hull direction from the forward-most gas jet port 2431 to the rearmost gas jet port 2432 in the third group.

[0095] The distance between the rearmost gas jet port of the front group and the frontmost gas jet port of the rear group may be different. For example, the distance S1 between the rearmost gas jet port 2414 of the first group and the frontmost gas jet port 2421 of the second group may be smaller than the distance S2 between the rearmost gas jet port 2428 of the second group and the frontmost gas jet port 2431 of the third group. Furthermore, the distance between the rearmost gas jet port of the front group and the frontmost gas jet port of the rear group may be larger than the distance between the gas jet ports of each group.

[0096] The distance L4 from the bisector or keel of the hull 110 to the gas jet port 2428 located at the outermost hull may be smaller than the distance L5 from the bisector or keel of the hull 110 to the sea chest 180. Preferably, L4 / L5 may be in the range of 0.5 to 0.7. More preferably, L4 / L5 may be in the range of 0.58 to 0.68.

[0097] Furthermore, the ratio S3 / L of the distance S3 from the keel, which is the outermost gas jet nozzle 2428, to the sea chest 180 relative to the length L of the hull 110 should be 0.5 or less. Preferably, S3 / L should be 0.48 or less.

[0098] The above conditions are effective in reducing the phenomenon of gas or air discharged from the gas jet ports 241, 242, and 243 flowing into the sea chest 180. Therefore, the ship 106 according to this embodiment can reduce the frictional resistance between the hull 110 and seawater by the friction reduction device 200, and can significantly reduce the resulting failure rate of the ship 106.

[0099] (Structure of the Carrier Ship According to the Present Invention) A vessel according to one embodiment will be described with reference to FIGS.

[0100] The vessel 107 according to this embodiment includes a propulsion device required for operation. For example, the vessel 107 includes a propeller 120 powered by an internal combustion engine. The propeller 120 is disposed on the stern side of the hull 110. A plurality of propellers 120 may be configured. For example, the propellers 120 may be disposed on both the left and right sides of the stern of the hull 110 to improve the operating speed or operating capacity of the vessel 107.

[0101] The vessel 107 includes a structure for transporting a liquefied substance. For example, a number of liquefied substance storage tanks 430 may be formed at intervals in the hull 110. The vessel 107 includes a structure for insulating or protecting the liquefied substance storage tanks 430. For example, a cofferdam 440 may be formed on one or both sides of the liquefied substance storage tank 430. A heating device 460 may be disposed in the cofferdam 440 to maintain the cofferdam 440 at a predetermined temperature.

[0102] The vessel 107 includes a device that can minimize frictional resistance between the hull 110 and seawater or freshwater. For example, the vessel 107 includes a friction reduction device 200 configured to inject gas (or air) onto the bottom of the hull 110, preferably onto a flat surface of the bottom.

[0103] The friction reduction device 200 is disposed on the bow side of the hull 110. However, the location of the friction reduction device 200 is not limited to the bow side of the hull 110. The friction reduction device 200 includes a compressor 210, a main pipe 220, an auxiliary pipe 230, and a gas injection port 240. However, the configuration of the friction reduction device 200 is not limited to the above-mentioned elements. For example, the friction reduction device 200 may further include valves disposed in the main pipe 220 and the auxiliary pipe 230, respectively.

[0104] The compressor 210 is disposed on the bow side of the hull 110 as shown in Fig. 32. Furthermore, the compressor 210 is preferably disposed higher than the load waterline of the hull 110 for smooth generation of compressed air and operational efficiency.

[0105] The main pipe 220 is connected to the compressor 210 and guides the compressed air generated by the compressor 210 to flow toward the stern. Furthermore, the main pipe 220 passes through a cofferdam 440 cooled by a liquefied substance storage tank 430, as shown in FIGS. 2 and 3, to prevent the compressed air generated by the compressor 210 from overheating. Therefore, the compressed air flowing through the main pipe 220 can be cooled to 93°C or less, preferably 80°C or less, before being discharged to the gas injection port 240. Cooling the compressed air through the main pipe 220 in this manner can prevent or reduce damage to the paint (anti-rust paint and anti-fouling paint) of the pipes 220 and 230 caused by overheated air.

[0106] The auxiliary pipes 230 are formed by branching off from the main pipe 220. As shown in FIG. 33, the auxiliary pipes 230 may branch off at predetermined intervals along the length of the main pipe 220 and then extend toward the stern. The widthwise lengths of the auxiliary pipes 230 branching off from the main pipe 220 may increase toward the stern, as shown in FIG. 2. For example, the widthwise length of the first auxiliary pipe 230 branching off from the main pipe 220 may be smaller than the widthwise length of the second auxiliary pipe 230 branching off from the main pipe 220, and the widthwise length of the second auxiliary pipe 230 branching off from the main pipe 220 may be shorter than the widthwise length of the third auxiliary pipe 230 branching off from the main pipe 220. The inner diameter of the auxiliary pipe 230 is preferably smaller than the inner diameter of the main pipe 220 to prevent a decrease in gas injection pressure. In addition, the inner diameter of the auxiliary pipe 230 may be different depending on the branching position from the main pipe 220. For example, the inner diameter of the first auxiliary pipe 230 branching off from the main pipe 220 may be larger than the inner diameter of the second auxiliary pipe 230 branching off from the main pipe 220, which in turn may be larger than the inner diameter of the third auxiliary pipe 230 branching off from the main pipe 220. However, the inner diameters of all the auxiliary pipes 230 may be the same if necessary.

[0107] The gas injection port 240 is connected to the auxiliary pipe 230. The gas injection port 240 is configured to inject compressed air or compressed gas supplied via the auxiliary pipe 230 into seawater. Preferably, the gas injection port 240 can inject the compressed air so that the compressed air flows along the surface of the bottom of the hull 110. For this reason, the final discharge direction of the gas injection port 240 is preferably approximately parallel to the bottom surface of the hull 110.

[0108] The ship 107 configured as described above can minimize damage to piping caused by high-temperature compressed air because the high-temperature, high-pressure air generated from the friction reduction device 200 is cooled while passing through the cofferdam 440. Furthermore, the ship 107 according to this embodiment can reduce power consumption required to heat the cofferdam 440 because the cofferdam 440 is heated by the compressed air from the friction reduction device 200. Therefore, the ship according to this embodiment can reduce construction costs and improve operation efficiency.

[0109] Next, a vessel according to another embodiment will be described with reference to Figures 35 and 36. For reference, in the following description, the same components as those in the above-described embodiment will be designated by the same reference numerals, and detailed description of these components will be omitted.

[0110] 35 , the ship 108 according to this embodiment includes a propeller 120 disposed at the stern of the hull 110, a plurality of liquefied substance storage tanks 430 formed in the hull 110, and a cofferdam 440. Furthermore, the ship 108 includes a friction reduction device 200.

[0111] The ship 108 according to this embodiment can be distinguished from the above-described embodiments in that, as shown in FIG. 36, a portion of the compressed air flowing through the main pipe 220 is selectively supplied to a cofferdam 440.

[0112] Additionally, the main pipe 220 is provided with a heat exchange pipe 470 that branches off to the cofferdam 440. The heat exchange pipe 470 passes through a substantial portion of the cofferdam 440 before returning to the main pipe 220. The heat exchange pipe 470 is provided with a number of fin members 472 to improve heat dissipation efficiency. A plurality of valves 510 and 520 are disposed on the heat exchange pipe 470. Therefore, high-temperature, high-pressure air flowing through the main pipe 220 can be supplied to the cofferdam 440 only when the valves 510 and 520 are open. Preferably, the valves 510 and 520 are opened when the temperature of the cofferdam 440 drops below a preset temperature, and closed when the temperature of the cofferdam 440 rises above the preset temperature.

[0113] The vessel 108 configured in this manner can significantly reduce the power consumption required to maintain the temperature of the cofferdam 440 because the temperature of the cofferdam 440 is selectively adjusted by the high-temperature, high-pressure air generated by the friction reduction device 200.

[0114] Next, a vessel according to yet another embodiment will be described with reference to Figures 37 and 38. For reference, in the following description, the same components as those in the above-described embodiment will be designated by the same reference numerals, and detailed description of these components will be omitted.

[0115] 37 , the vessel 109 according to this embodiment includes a propeller 120 disposed at the stern of the hull 110, a plurality of liquefied substance storage tanks 430 formed in the hull 110, and a cofferdam 440. Furthermore, the vessel 108 includes an equalizing water tank 570 and a friction reduction device 200.

[0116] 38, the ship 109 according to this embodiment is distinguished from the above-described embodiments in that the high-temperature, high-pressure air flowing through the main pipe 220 passes through at least one of a cofferdam 440 and an equilibrium water tank 570. For this reason, the main pipe 220 is formed with a first heat exchange pipe 470 branching off to the cofferdam 440 and a second heat exchange pipe 480 branching off to the equilibrium water tank 570. The first heat exchange pipe 470 and the second heat exchange pipe 480 are provided with one or more valves 510, 520, 530, 340 for controlling the flow of air.

[0117] The vessel 109 configured in this manner can route the high-temperature, high-pressure air discharged from the friction reduction device 200 to the cofferdam 440, or to the balancing water tank 570, or to both the cofferdam 440 and the balancing water tank 570. For example, when the cofferdam 440 is in a supercooled state, the first valves 510 and 520 can be opened and the second valves 530 and 340 can be closed so that the high-temperature air discharged from the friction reduction device 200 is supplied to the cofferdam 440. On the other hand, when the temperature of the cofferdam 440 meets a preset standard, the first valves 510 and 520 can be closed and the second valves 530 and 340 can be opened so that the air discharged from the friction reduction device 200 is supplied to the balancing water tank 570.

[0118] Therefore, the ship 109 according to this embodiment can not only prevent the cofferdam 440 from being overcooled by the high-temperature, high-pressure air, but also significantly reduce damage to the piping caused by the high-temperature, high-pressure air.

[0119] Referring to FIG. 39, a vessel according to another embodiment will be described.

[0120] The ship 109 according to this embodiment is distinguished from the above-described embodiments in the arrangement of the cofferdam 440 and the balancing water tank 570.

[0121] In this embodiment, the cofferdam 440 can be arranged as close as possible to the balancing water tank 570. For example, the cofferdam 440 may be arranged in close contact with the balancing water tank 570. Such a structure may allow the cofferdam 440 to be cooled or heated by seawater stored in the balancing water tank 570.

[0122] Alternatively, the main pipe 220 may be arranged to pass through an equalization water tank 570. Furthermore, the heat exchange pipe 470 branching off from the main pipe 220 may be arranged to pass through a cofferdam 440.

[0123] The ship configured as described above can suppress overheating or overcooling of the cofferdam 440 via the balance water tank 570, the main piping 220, and the heat exchange piping 470.

[0124] (Hydraulic circuit of friction reduction device) The friction reduction device 200 of the vessels 100, 101, 102, 103, 104, 105, 106, 108, 109 described above may include a unique hydraulic circuit.

[0125] First, with reference to FIG. 40, a configuration according to one embodiment of the friction reduction device 200 will be described.

[0126] The friction reduction device 200 includes a compressor 210, a main pipe 220, an auxiliary pipe 230, and a gas injection port 240. Furthermore, the friction reduction device 200 further includes a bypass pipe 206 and valves 710, 720, 730, 740, and 760 to prevent overload of the compressor 210 and to prevent inflow of seawater.

[0127] A plurality of compressors 210 may be provided. For example, the friction reduction device 200 according to this embodiment may include three compressors 210. The three compressors 210 are connected in parallel by a first connecting pipe 202. The first connecting pipe 202 is connected in series to the main pipe 220 by a second connecting pipe 204. Therefore, even if one of the compressors 210 breaks down or malfunctions, the remaining compressors 210 can supply compressed air (or compressed gas) at a constant pressure and flow rate to the gas injection port 240. For reference, although the present embodiment illustrates three compressors 210 connected in parallel, two or four or more compressors 210 may be connected in parallel as needed.

[0128] Valves 720, 730, and 760 are attached to the bypass pipe 206, the main pipe 220, and the auxiliary pipe 230. The valves 720, 730, and 760 are connected to a control unit of the friction reduction device 200 and can open or close the bypass pipe 206, the main pipe 220, and the auxiliary pipe 230 in response to a control signal. For example, the valves 720, 730, and 760 can operate to open the main pipe 220 and the auxiliary pipe 230 and close the bypass pipe 206 when the friction reduction device 200 is operating. In contrast, the valves 710, 720, 730, and 760 can operate to close the main pipe 220 and the auxiliary pipe 230 and open the bypass pipe 206 when the friction reduction device 200 is operating.

[0129] A separate valve 740 may be further attached to the auxiliary pipe 230 or the gas injection port 240. For example, the auxiliary pipe 230 may be attached with a check valve 740 capable of blocking the inflow of seawater.

[0130] The following describes a valve control method for the friction reduction device 200 configured as described above. The friction reduction device 200 can be activated depending on the operating state of the ship 100. For example, the friction reduction device 200 can be stopped when the ship 100 is at anchor and activated when the ship 100 is operating.

[0131] When the ship 100 is operating, the friction reduction device 200 controls the valves 710, 720, 730, 740, and 760 so that the compressed air generated from the compressor 210 can be smoothly discharged through the gas injection port 240. In addition, when the operating state of the ship 100 is detected, the friction reduction device 200 operates the compressor 210 and opens all of the valves 710, 720, 730, and 740. However, the friction reduction device 200 closes the valve 760 so that the compressed air of the compressor 210 does not leak through the bypass pipe 206.

[0132] When the ship 100 is anchored, the friction reduction device 200 controls the valves 710, 720, 730, 740, and 760 to prevent overload on the compressor 210. Specifically, the friction reduction device 200 stops the compressor 210 when it detects that the ship 100 is anchored or that the operating speed of the ship 100 is below a set reference value. However, if the compressor 210 suddenly stops, seawater may flow in through the gas injection port 240, the auxiliary pipe 230, and the main pipe 220. Therefore, the friction reduction device 200 sequentially closes the valves 740, 730, 720, and 710 before stopping the compressor 210. Preferably, the friction reduction device 200 can sequentially close the valves 740, 730, 720, and 710 while continuously operating the compressor 210 and maintaining constant pressure inside the auxiliary pipe 230 and the main pipe 220. When the inflow of seawater through the auxiliary pipe 230 and the main pipe 220 is blocked, the friction reduction device 200 opens the valve 760 of the bypass pipe 206 to prevent the pressure of the compressor 210 from increasing. For example, when the internal pressure of the compressor 210 exceeds a set upper limit, the friction reduction device 200 can open the valve 760 of the bypass pipe 206. Thereafter, when the internal pressure of the compressor 210 drops below the set upper limit, the friction reduction device 200 can stop the compressor 210 and close the valve 760.

[0133] The ship 100 configured as described above can block the inflow of seawater using the friction reduction device 200 through the bypass piping 206 and multiple valves, and suppress the overload phenomenon of the compressor 210, thereby improving the efficiency of the friction reduction device 200.

[0134] The configuration of a vessel according to another embodiment will be described with reference to FIG.

[0135] The vessel 100 according to this embodiment can be distinguished from the above-described embodiments in that it further includes a pressure measuring device 410 as shown in FIG.

[0136] The pressure measuring device 410 is disposed in the main pipe 220. Preferably, the pressure measuring device 410 is disposed at the rear end of the main pipe 220. However, the location of the pressure measuring device 410 is not limited to the rear end of the main pipe 220. As an example, the pressure measuring device 410 may be disposed at any position in the main pipe 220 as long as it can measure the pressure of the air supplied via the main pipe 220. As another example, multiple pressure measuring devices 410 may be disposed in each auxiliary pipe 230.

[0137] The pressure measuring device 410 can measure the pressure of air supplied to the main pipe 220 via the compressor 210. In addition, when the pressure measuring device 410 measures that the air pressure in the main pipe 220 is outside a set lower limit or upper limit, it can send out a control signal to start or stop the operation of the compressor 210.

[0138] The present invention is not limited to the above-described examples, and a person skilled in the art to which the present invention pertains can make any number of modifications and variations without departing from the spirit and scope of the technical ideas of the present invention as set forth in the following claims. For example, various features described in the above-described embodiments can be combined and applied to other embodiments unless explicitly stated to the contrary.

Claims

1. a storage tank for storing liquefied material in the hull; a cofferdam formed on one side of the storage tank; a heating device disposed in the cofferdam; an equalization water tank provided in the hull and storing seawater; a friction reduction device provided on the hull and configured to inject gas to the outside of the hull, the friction reduction device includes a main pipe and an auxiliary pipe through which high-temperature gas generated from the friction reduction device flows, At least one of the main pipe and the auxiliary pipe passes through the inside of the balancing water tank, The main pipe is formed to pass through the inside of the cofferdam, The heating device is arranged separately from the main piping within the cofferdam to maintain the temperature of the cofferdam.

2. The balancing water tank is a first balancing water tank disposed on the bow side of the hull and formed along the height direction of the hull; 2. The vessel according to claim 1, further comprising: a second balancing water tank disposed on a bottom side of the hull and formed along the length of the hull.

3. The main pipe is The watercraft of claim 2 , wherein the watercraft is arranged to pass through the first balancing water tank.

4. The first balancing water tank is composed of a plurality of tanks, The ship according to claim 2 , wherein the main pipe is configured in a plurality of parts so as to pass through each of the plurality of first balance water tanks.

5. The auxiliary piping is 3. The marine vessel of claim 2, configured to connect the main pipe and a gas jet through the second balance water tank.

6. the friction reduction device includes a gas injection port that injects gas to reduce frictional resistance between the hull and seawater, The gas injection port is a main body having an inclined surface or a curved portion; a bottom portion coupled to the main body portion and having an outlet formed therein for injecting gas; The watercraft of claim 1 , wherein the ramps are configured to have different slopes along the length of the ramps.

7. The inclined surface is a first inclined portion having a first gradient; a second ramp having a second slope.

8. The watercraft according to claim 7 , wherein a height L1 of the first inclined portion is greater than a height L2 of the second inclined portion.

9. The curved portion is a first curved portion having a first radius of curvature; a second curved portion having a second radius of curvature.

10. The friction reduction device is The hull includes a plurality of gas jet ports arranged symmetrically around the keel, The plurality of gas injection ports are The gas jet nozzles are classified into a first group, a second group, and a third group from the bow side of the hull, a maximum interval W1 between the first group of gas injection ports is smaller than a minimum interval W2 between the second group of gas injection ports and a minimum interval W4 between the third group of gas injection ports; 2. The vessel according to claim 1, wherein a maximum spacing W5 between the gas jet ports of the third group is greater than a minimum spacing W2 between the gas jet ports of the second group and is smaller than a maximum spacing W3 between the gas jet ports of the second group.

11. The vessel according to claim 10, wherein the third group of gas jet ports are arranged to partially overlap the first group of gas jet ports or the second group of gas jet ports.

12. 11. The vessel according to claim 10, wherein a distance L1 from a forward-most gas jet nozzle to a rear-most gas jet nozzle constituting the first group of gas jet nozzles is smaller than a distance L2 from a forward-most gas jet nozzle to a rear-most gas jet nozzle constituting the second group of gas jet nozzles, and is larger than a distance L3 from a forward-most gas jet nozzle to a rear-most gas jet nozzle constituting the third group of gas jet nozzles.

13. The watercraft according to claim 10, wherein a sea chest is formed in a side of the hull.

14. 14. The ship according to claim 13, wherein a distance L4 from the keel of the hull to a gas jet nozzle arranged at the outermost periphery among the plurality of gas jet nozzles is shorter than a distance L5 from the keel to the sea chest.

15. 14. The ship according to claim 13, wherein a ratio L4 / L5 between a distance L4 from a keel of the hull to a gas jet port arranged at the outermost position among the plurality of gas jet ports and a distance L5 from the keel to the sea chest is 0.5 to 0.

7.

16. 14. The ship according to claim 13, wherein a ratio S3 / L between a distance S3 from a gas jet nozzle located outermost from a keel of the hull to the sea chest among the plurality of gas jet nozzles and a length L of the hull is 0.5 or less.

17. 14. The vessel according to claim 13, further comprising a wing member formed on the hull and extending from a lower portion of the sea chest toward a bow of the hull to prevent gas generated by the friction reduction device from flowing into the sea chest.

18. The vessel according to claim 17 , wherein the wing members are curved upward as they move toward the bow of the hull.

19. 18. The marine vessel of claim 17, wherein the wing member includes a downwardly bent fold.

20. The friction reduction device is a compressor disposed in the hull; a gas jet nozzle disposed on the hull for jetting gas to reduce frictional resistance between the hull and seawater; a main pipe and an auxiliary pipe connecting the compressor and the gas injection port; a bypass pipe connected to the compressor; a control unit that operates opening and closing of the main pipe, the auxiliary pipe, and the bypass pipe in accordance with a control signal.

21. The ship according to claim 20, wherein the control unit is configured to open a valve of the bypass pipe when an internal pressure of the compressor exceeds a set upper limit value.

22. The ship according to claim 20 , wherein the control unit is configured to close the valve of the bypass pipe when the internal pressure of the compressor is equal to or lower than a set upper limit value.

23. The ship according to claim 1 , wherein the main piping includes a heat exchange piping branched off from the cofferdam.

24. 2. The ship according to claim 1, wherein the main piping includes a first heat exchange piping branched off to the cofferdam and a second heat exchange piping branched off to the balance water tank.

Images