JP7729888B2 - ship - Google Patents

Description

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

Ships sailing on the ocean experience a large amount of frictional resistance from seawater while sailing, as a large portion of the hull is submerged in seawater. This frictional resistance from seawater accounts for approximately 80% of the total resistance for slow-speed ships and approximately 50% for fast-speed ships.

Frictional resistance that occurs on a ship's 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 described above can be significantly reduced.

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.

However, because friction reduction devices use a compressor to generate and discharge high-pressure gas, the temperature of the discharged gas far exceeds 100°C. However, this high-temperature, high-pressure gas can cause damage to the anti-rust and anti-fouling paint on the piping that serves as the gas discharge passage and on surrounding components.

Furthermore, there is a problem in that the gases and air discharged from friction reduction devices flow into the ship's sea chest, disrupting the ship's normal operation. Therefore, there is a need to develop technology that can reduce the phenomenon of gases and air discharged from such devices flowing into the ship's sea chest.

The purpose of the present invention is to provide a ship that can minimize damage to piping caused by high-temperature, high-pressure gas discharged from a friction reduction device.

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 the sea chest.

To achieve the above object, one embodiment of the present invention provides a vessel including an equalization water tank provided on the hull, and a friction reduction device provided on the hull and configured to inject gas to the outside of 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 equalization water tank.

The present invention can reduce damage to piping caused by high-temperature, high-pressure gas discharged from friction reduction devices.

The present invention can effectively reduce the phenomenon of gas (or air) injected into the friction reduction device flowing into the sea chest.

The present invention improves the directness of the air injected into the friction reduction device, effectively reducing frictional resistance between the hull and seawater.

1 is a side view of a vessel according to an embodiment of the present invention. FIG. 2 is a plan view of the ship shown in FIG. 1 . FIG. 2 is a perspective view of a main part showing the arrangement of a compressor and an equilibrium water tank of the ship shown in FIG. 1 . FIG. 10 is a side view of a vessel according to another embodiment of the present invention. FIG. 5 is a plan view of the vessel shown in FIG. 4 . FIG. 5 is a perspective view of a main part showing the arrangement of a compressor and an equilibrium water tank of the ship shown in FIG. 4 . FIG. 10 is a plan view of a vessel according to yet another embodiment of the present invention. FIG. 8 is a perspective view of a main part of the vessel shown in FIG. 7 . FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. FIG. 10 is a plan view of the vessel shown in FIG. FIG. 10 is a perspective view of a main part showing the arrangement of a compressor and an equilibrium water tank of the ship shown in FIG. FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. FIG. 13 is a plan view of the vessel shown in FIG. 12. FIG. 13 is a perspective view of a main part showing the arrangement of a compressor and an equilibrium water tank of the ship shown in FIG. 12 . FIG. 2 is a bottom view of the vessel shown in FIG. 1 . FIG. 2 is a bottom view of the vessel shown in FIG. 1 . FIG. 10 is a bottom view of a vessel according to another embodiment of the present invention. FIG. 10 is a bottom view of a vessel according to another embodiment of the present invention. FIG. 3 is a perspective view of a main part of the gas injection port shown in FIG. 2 . 20 is a cross-sectional view taken along line AA of the gas injection port shown in FIG. 19. FIG. 10 is a cross-sectional view taken along line AA of another embodiment of the gas jet nozzle. FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. FIG. 10 is a cross-sectional view taken along line AA of still another embodiment of the gas injection port. FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. FIG. 27 is an enlarged view of part A shown in FIG. 26. FIG. 28 is a cross-sectional view of the wing member shown in FIG. 27. FIG. 27 is a configuration diagram of the friction reduction device shown in FIG. 26. FIG. 27 is a bottom view of the vessel shown in FIG. 26. FIG. 27 is a bottom view of the vessel shown in FIG. 26. FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. FIG. 33 is a plan view of the vessel shown in FIG. 32. FIG. 33 is a perspective view of a main part showing the main piping of a compressor arranged in the cofferdam shown in FIG. 32. FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. FIG. 36 is a detailed view showing the arrangement relationship between the cofferdam and the main pipe shown in FIG. 35. FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. FIG. 38 is a detailed view showing the layout relationship of the cofferdam, balancing water tank, and main piping shown in FIG. 37. FIG. 10 is a side view of a vessel according to yet another embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram for the main components of the friction reduction device described above. FIG. 10 is a hydraulic circuit diagram of a friction reduction device according to another embodiment.

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.

In addition, throughout the specification, when a component is "connected" to another component, it means not only when these components are "directly connected" but also when they are "indirectly connected" via another component. Furthermore, unless otherwise specified, when a component "includes" another component, it does not mean that it excludes other components, but that it may further include other components.

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

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. Multiple 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.

The ship 100 includes devices for stable operation. 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 located on the bow side of the hull 110 and is generally formed high along the height direction of the hull 110. The second balancing water tank 140 is located on the bottom side of the hull 110 and is generally formed long along the length direction of the hull 110. In addition, the first balancing water tank 130 and the second balancing water tank 140 are arranged symmetrically around the keel of the hull 110, as shown in FIG. 2.

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.

The friction reduction device 200 is arranged on the bow side of the hull 110. However, the arrangement position 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 arranged in the main pipe 220 and the auxiliary pipe 230, respectively.

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 efficient operation. 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.

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 Figures 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 below 93°C, preferably below 80°C, before moving toward the stern. Cooling the compressed air in this manner through the main pipe 220 can prevent or reduce damage to the anti-corrosion and anti-fouling paint applied to the main pipe 220, auxiliary pipe 230, and hull 110 caused by overheated air.

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. 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 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. Furthermore, 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 the same.

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 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.

The ship 100 configured as described above can minimize damage to piping caused by high-temperature compressed air because the high-temperature, high-pressure air generated by the friction reduction device 200 is cooled while passing through the balance water tank. Furthermore, the ship 100 according to this embodiment can omit a separate device for cooling the compressed air because the compressed air is cooled through the balance water tank. Therefore, the ship according to this embodiment can not only reduce construction costs but also improve the utilization rate of the ship's interior space.

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 descriptions of these components will be omitted.

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

The ship 101 according to this embodiment can be distinguished from the above-described embodiments in that it includes multiple main pipes 220, 222, as shown in Figures 5 and 6. Specifically, the compressed air generated from the compressor 210 can be supplied to the respective gas injection ports 240, 242 via the first main pipe 220 and the second main pipe 222. Furthermore, the first main pipe 220 and the second main pipe 222 can be cooled by the first balance water tank 130 and the first balance water tank 132, respectively.

The ship 101 configured in this manner supplies compressed air to each gas injection port 240, 242 via multiple main pipes 220, 222, thereby improving the friction reduction effect of the hull 110 due to air injection. Furthermore, in the ship 101 according to this embodiment, the main pipes 220, 222 are cooled by the respective balance water tanks 130, 132, thereby also improving the cooling efficiency of the balance water tanks 130, 132.

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 descriptions of these components will be omitted.

The vessel 102 according to this embodiment is distinguished from the above-described embodiments in that it is composed of a single balancing water tank 130. Furthermore, the main pipe 220 is configured to vertically penetrate the central portion of the balancing water tank 130. For reference, this embodiment shows one main pipe 220 vertically penetrating 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.

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.

The ship 103 of this embodiment is distinguished from the above-described embodiments in the arrangement of the auxiliary piping 220.

The auxiliary pipe 230 passes through the second balancing water tank 140 as shown in Figures 10 and 11 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 can extend to the flat surface of the bottom of the ship after passing through the internal space of the second balancing water tank 140. Therefore, the compressed air flowing through the auxiliary pipe 230 can be cooled to below 93°C, preferably below 80°C, before moving toward the stern. Cooling the compressed air through the auxiliary pipe 230 in this manner can prevent or reduce damage to the anti-corrosion and anti-fouling paint formed inside the main pipe 220 and auxiliary pipe 230 caused by overheated air.

The ship 103 configured as described above can minimize damage to piping caused by high-temperature compressed air because the high-temperature, high-pressure air generated by the friction reduction device 200 is cooled while passing through the balance water tank. Furthermore, the ship 103 according to this embodiment cools the compressed air through the balance water tank, eliminating the need for a separate device for cooling the compressed air. Therefore, the ship according to this embodiment can not only reduce construction costs but also improve the utilization rate of the ship's interior space.

Next, a vessel according to yet 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.

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

The vessel 104 according to this embodiment can be distinguished from the above-described embodiments in that it includes multiple main pipes 220, 222, as shown in Figures 13 and 14. The vessel 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.

Additionally, the compressed air generated from the compressor 210 can 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 balance water tank 130 and the first balance water tank 132 so that the compressed air can be primarily cooled. Furthermore, the first auxiliary pipe 230 and the second auxiliary pipe 232 may be configured to pass through the second balance water tanks 140, 142 so that the compressed air supplied via the main pipes 220, 222 can be secondarily cooled.

The ship 104 configured in this manner supplies compressed air to each gas injection port 240, 242 via multiple main pipes 220, 222, thereby improving the friction reduction effect of the hull 110 due to air injection. 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, thereby improving the cooling efficiency of the equilibrium water tanks 130, 132, 140, 142.

[Gas injection port arrangement structure]
The arrangement of the gas injection ports will be described with reference to FIGS. 15 and 16. FIG.

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

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 fewer 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 number of gas injection ports 241, 243 constituting the first and third groups.

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 the gas injection ports 2414 in the first group may be smaller than the minimum spacing W2 between the gas injection ports 2428 in the second group, and smaller than the minimum spacing W4 between the gas injection ports 2431 in the third group. Furthermore, the maximum spacing W5 between the gas injection ports 2432 in the third group may be larger than the minimum spacing W2 between the gas injection ports 2428 in the second group, and smaller than the maximum spacing W3 between the gas injection ports 2428 in the second group.

The distance from the forward-most gas jet nozzle to the rearmost gas jet nozzle in each group may differ 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 2414 in the first group may be smaller than the length L2 in the hull direction from the forward-most gas jet nozzle 2421 to the rearmost gas jet nozzle 2428 in the second group, and may be greater than the length L3 in the hull direction from the forward-most gas jet nozzle 2431 to the rearmost gas jet nozzle 2432 in the third group.

The distance between the gas jet nozzle located at the rear end of the front group and the gas jet nozzle located at the front end of the rear group may be different. For example, the distance S1 between the gas jet nozzle 2414 located at the rear end of the first group and the gas jet nozzle 2421 located at the front end of the second group may be smaller than the distance S2 between the gas jet nozzle 2428 located at the rear end of the second group and the gas jet nozzle 2431 located at the front end of the third group. Furthermore, the distance between the gas jet nozzle located at the rear end of the front group and the gas jet nozzle located at the front end of the rear group may be larger than the distance between the gas jet nozzles of each group.

The distance L4 from the bisector or keel of the hull 110 to the outermost gas jet port 2428 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.

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.

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

With reference to Figures 17 and 18, the arrangement of gas jet nozzles on a ship in another embodiment will be described.

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

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

The number of gas injection ports 241, 242 may differ between the first and second groups. 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.

The maximum and minimum spacing between pairs of gas injection ports 241, 242 may differ 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.

The distance from the forward-most gas jet nozzle to the rearmost gas jet nozzle in each group may differ 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.

The distance S2 between the rearmost gas jet 2412 in the first group and the frontmost gas jet 2421 in the second group can be quite large. For example, S2 may be smaller than L1 but larger than L1/2.

The distance L4 from the bisector or keel of the hull 110 to the outermost gas jet port 2422 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.

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.

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

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

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 a plurality of 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 of the inclined surface of the main body 242 forming the first inclined portion 2422 may be greater than the length of the section of the inclined surface of the main body 242 forming the second inclined portion 2424. Furthermore, the height Nh1 of the first inclined portion 2422 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.

The bottom 244 is formed at the bottom of the main body 242. The bottom 244 is configured to generally close the open mouth of the main body 242. The bottom 244 is formed with an exhaust port 2442 for injecting or discharging high-pressure air. Additionally, the exhaust port 2442 is formed at the point where the second inclined portion 2424 and the bottom 244 meet.

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

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

The gas injection port 2402 of 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.

The gas injection port 2402 formed as described above limits the flow of high-pressure air using the second inclined portion 2424 and the second protrusion 246, thereby further improving 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.

Referring to Figure 22, other configurations of gas injection ports will be described.

The gas injection port 2404 of this embodiment is distinguished from the above-described embodiment in that it further includes a second protrusion 248, as shown in FIG. 6 . 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. An inclined surface is formed on the second protrusion 248. 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.

The gas injection port 2404 formed as described above limits and guides the flow of high-pressure air through the multiple inclined portions 2422, 2424 and multiple 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 longer period of time.

Referring to Figure 23, we will explain yet another form of gas injection port.

The gas injection port 2408 of this embodiment is distinguished from the above-described embodiment in that the inclined surface of the main body 242 is composed of a single curved portion, as shown in Figure 7. Additionally, the inclined surface may be composed of a first curved portion 2422 having a first radius of curvature R1.

Referring to Figure 24, we will explain yet another form of gas injection port.

The gas injection port 2406 of this embodiment is distinguished from the above-described embodiment in that, as shown in FIG. 8, the inclined surface of the main body 242 is composed of multiple 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.

Referring to Figure 25, we will explain yet another form of gas injection port.

As shown in FIG. 9, the gas outlet 2406 of 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.

[Hull air bubble inflow prevention structure]
A vessel according to another embodiment will be described with reference to FIGS.

The vessel 106 in this embodiment includes a propulsion device necessary 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. Multiple 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.

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.

The vessel 106 includes a device capable of minimizing 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.

The friction reduction device 200 is arranged on the bow side of the hull 110. However, the arrangement position 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 arranged on the bow side of the hull 110 as shown in FIG. 26. It is preferable that the compressor 210 be arranged higher than the load waterline of the hull 110 for smooth generation of compressed air (or compressed gas) and operating efficiency.

The hull 110 is formed with wing members 160 to prevent gas generated by the friction reduction device 200 from flowing into the sea chest 180. As shown in FIG. 1, the wing members 160 may be formed elongated from the bottom of the sea chest 180 toward the bow of the hull 110.

The wing member 160 may be formed with a considerable 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 dimensions.

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.

The wing member 160 is configured to minimize the phenomenon of gas generated by the friction reduction device 200 rising 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.

The wing member 160 formed in this manner can maximize the friction reduction effect of the gas generated by the friction reduction device 200 by concentrating the gas generated by the friction reduction device 200 below the load waterline of the hull 110.

As shown in FIG. 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, etc., arranged in the main pipe 220 and the auxiliary pipe 230, respectively.

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. Multiple main pipes 220 may be configured. For example, two main pipes 220 may be configured.

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. Furthermore, 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 the auxiliary pipes 230 may all be formed to be the same size.

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

The arrangement of the gas injection ports will be explained in detail with reference to Figures 30 and 31.

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

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 fewer 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 number of gas injection ports 241, 243 constituting the first and third groups.

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 the gas injection ports 2414 in the first group may be smaller than the minimum spacing W2 between the gas injection ports 2428 in the second group, and smaller than the minimum spacing W4 between the gas injection ports 2431 in the third group. Furthermore, the maximum spacing W5 between the gas injection ports 2432 in the third group may be larger than the minimum spacing W2 between the gas injection ports 2428 in the second group, and smaller than the maximum spacing W3 between the gas injection ports 2428 in the second group.

The distance from the forward-most gas jet nozzle to the rearmost gas jet nozzle in each group may differ 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 2414 in the first group may be smaller than the length L2 in the hull direction from the forward-most gas jet nozzle 2421 to the rearmost gas jet nozzle 2428 in the second group, and may be greater than the length L3 in the hull direction from the forward-most gas jet nozzle 2431 to the rearmost gas jet nozzle 2432 in the third group.

The distance between the gas jet nozzle located at the rear end of the front group and the gas jet nozzle located at the front end of the rear group may be different. For example, the distance S1 between the gas jet nozzle 2414 located at the rear end of the first group and the gas jet nozzle 2421 located at the front end of the second group may be smaller than the distance S2 between the gas jet nozzle 2428 located at the rear end of the second group and the gas jet nozzle 2431 located at the front end of the third group. Furthermore, the distance between the gas jet nozzle located at the rear end of the front group and the gas jet nozzle located at the front end of the rear group may be larger than the distance between the gas jet nozzles of each group.

The distance L4 from the bisector or keel of the hull 110 to the outermost gas jet port 2428 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.

Furthermore, the ratio S3/L of the distance S3 from the keel to the outermost gas jet nozzle 2428 located at 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.

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

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

The vessel 107 in this embodiment includes a propulsion device necessary for operation. For example, the vessel 107 includes a propeller 120 powered by an internal combustion engine. The propeller 120 is located on the stern side of the hull 110. Multiple propellers 120 may be configured. For example, the propellers 120 may be located 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.

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

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.

The friction reduction device 200 is arranged on the bow side of the hull 110. However, the arrangement position 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 arranged in the main pipe 220 and the auxiliary pipe 230, respectively.

The compressor 210 is located on the bow side of the hull 110, as shown in Figure 32. It is also preferable that the compressor 210 be located higher than the load waterline of the hull 110 to ensure smooth generation of compressed air and efficient operation.

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 that is cooled by the liquefied material 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 below 93°C, preferably below 80°C, before being discharged to the gas injection port 240. Cooling the compressed air in this manner through the main pipe 220 can prevent or mitigate damage to the paint (anti-rust paint and anti-fouling paint) on the pipes 220 and 230 caused by overheated air.

The auxiliary pipes 230 are formed by branching off from the main pipe 220. As shown in FIG. 33, the auxiliary pipes 230 can 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 can 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 can 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 can 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. Furthermore, the inner diameter of the auxiliary pipe 230 can 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 the same.

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 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.

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 by the friction reduction device 200 is cooled as it passes through the cofferdam 440. Furthermore, the ship 107 according to this embodiment can reduce the 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 operating efficiency.

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 descriptions of these components will be omitted.

As shown in FIG. 35, the vessel 108 of this embodiment includes a propeller 120 arranged at the stern of the hull 110, multiple liquefied substance storage tanks 430 formed in the hull 110, and a cofferdam 440. Furthermore, the vessel 108 includes a friction reduction device 200.

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

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 significant 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.

The vessel 108 configured in this manner can selectively adjust the temperature of the cofferdam 440 using the high-temperature, high-pressure air generated by the friction reduction device 200, significantly reducing the power consumption required to maintain the temperature of the cofferdam 440.

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 descriptions of these components will be omitted.

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

As shown in FIG. 38, the ship 109 of 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 the cofferdam 440 and the equilibrium water tank 570. To this end, the main pipe 220 is provided with a first heat exchange pipe 470 that branches off to the cofferdam 440 and a second heat exchange pipe 480 that branches off to the equilibrium water tank 570. One or more valves 510, 520, 530, 340 for controlling the flow of air are arranged in the first heat exchange pipe 470 and the second heat exchange pipe 480.

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 supercooled, 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. In contrast, 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.

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

Referring to Figure 39, we will explain another embodiment of the vessel.

The vessel 109 of this embodiment is distinguished from the above-described embodiments in the arrangement of the cofferdam 440 and the balancing water tank 570.

In this embodiment, the cofferdam 440 can be positioned as close as possible to the balancing water tank 570. For example, the cofferdam 440 may be positioned 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.

Alternatively, the main pipe 220 can 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.

A ship configured as described above can prevent overheating or overcooling of the cofferdam 440 through the balance water tank 570, main piping 220, and heat exchange piping 470.

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

First, referring to Figure 40, the configuration of one embodiment of the friction reduction device 200 will be described.

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 the inflow of seawater.

The compressor 210 may be configured with multiple compressors. For example, the friction reduction device 200 of 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 fails 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 this embodiment shows three compressors 210 connected in parallel, two or four or more compressors 210 can be connected in parallel as needed.

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

A separate valve 740 may be further installed in the auxiliary pipe 230 or the gas injection port 240. For example, the auxiliary pipe 230 may be equipped with a check valve 740 that can block the inflow of seawater.

The following describes a valve control method for the friction reduction device 200 configured as described above. The friction reduction device 200 can operate 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 can be operated when the ship 100 is operating.

When the ship 100 is operating, the friction reduction device 200 controls valves 710, 720, 730, 740, and 760 so that compressed air generated by 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 activates the compressor 210 and opens all of the valves 710, 720, 730, and 740. However, the friction reduction device 200 closes valve 760 to prevent compressed air from the compressor 210 from leaking through the bypass pipe 206.

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 ship's operating speed is below a set reference value. However, if the compressor 210 suddenly stops, seawater may flow in through the gas injection port 240, auxiliary pipe 230, and 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 continuously operate the compressor 210 to maintain constant pressure inside the auxiliary pipe 230 and main pipe 220 while sequentially closing the valves 740, 730, 720, and 710. 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 in 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.

The ship 100 configured as described above uses the friction reduction device 200 to block the inflow of seawater via the bypass piping 206 and numerous valves, and suppresses overload of the compressor 210, thereby improving the efficiency of the friction reduction device 200.

With reference to Figure 41, the configuration of a vessel according to another embodiment will be described.

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. 41.

The pressure measuring device 410 is arranged in the main pipe 220. Preferably, the pressure measuring device 410 is arranged at the rear end of the main pipe 220. However, the arrangement position 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 can be arranged at any position in the main pipe 220 as long as it is possible to measure the air pressure supplied via the main pipe 220. As another example, multiple pressure measuring devices 410 may be arranged in each auxiliary pipe 230.

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

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 (24)

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. 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. The main pipe is
The watercraft of claim 2 , wherein the watercraft is arranged to pass through the first balancing water tank. 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. 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. 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. The inclined surface is
a first inclined portion having a first gradient;
a second ramp having a second slope. The vessel described in claim 7, wherein the height L1 of the first inclined portion is greater than the height L2 of the second inclined portion. The curved portion is
a first curved portion having a first radius of curvature;
a second curved portion having a second radius of curvature. 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. The vessel described in claim 10, wherein the third group of gas jet nozzles are arranged to partially overlap the first group of gas jet nozzles or the second group of gas jet nozzles. The vessel described in claim 10, wherein the distance L1 from the forward-most gas jet nozzle to the rear-most gas jet nozzle constituting the first group of gas jet nozzles is smaller than the distance L2 from the forward-most gas jet nozzle to the rear-most gas jet nozzle constituting the second group of gas jet nozzles, and is greater than the distance L3 from the forward-most gas jet nozzle to the rear-most gas jet nozzle constituting the third group of gas jet nozzles. A vessel as described in claim 10, wherein a sea chest is formed on the side of the hull. A vessel as described in claim 13, wherein the distance L4 from the keel of the hull to the outermost gas jet nozzle among the multiple gas jet nozzles is shorter than the distance L5 from the keel to the sea chest. A vessel as described in claim 13, wherein the ratio L4/L5 between the distance L4 from the keel of the hull to the outermost gas jet nozzle among the multiple gas jet nozzles and the distance L5 from the keel to the sea chest is 0.5 to 0.7. A vessel as described in claim 13, wherein the ratio S3/L between the distance S3 from the gas jet nozzle located outermost from the keel of the hull to the sea chest and the length L of the hull is 0.5 or less. The vessel described in claim 13 further includes a wing member formed on the hull and extending from a lower portion of the sea chest toward the bow of the hull to prevent gas generated by the friction reduction device from flowing into the sea chest. The vessel described in claim 17, wherein the wing members are curved upward as they move toward the bow of the hull. The watercraft described in claim 17, wherein the wing member includes a downwardly bent portion. 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. The ship described in claim 20, wherein the control unit is configured to open the valve of the bypass piping when the internal pressure of the compressor exceeds a set upper limit value. The vessel described in claim 20, wherein the control unit is configured to close the valve of the bypass piping when the internal pressure of the compressor is below a set upper limit value. The ship described in claim 1, wherein the main piping includes a heat exchange piping branched off from the cofferdam. 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 balancing water tank.