Vessel

Abstract

To provide a vessel reducing damage to piping due to high temperature and high pressure gas exhausted from a friction reduction device as well as alleviating phenomenon of gas ejected from the friction reduction device from flowing into a sea chest.SOLUTION: A friction reduction device includes a gas ejection opening 240 and a bottom unit where an exhaust opening is formed for ejection of gas by coupling with a body unit having an inclined surface or a curved unit and compressed air provided to the gas ejection opening 240 is cooled by having compressed air provided through a first equilibrium tank 130 and a second equilibrium tank 140.SELECTED DRAWING: Figure 2

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 ship sailing on the ocean experiences a lot of frictional resistance from seawater because a large part of the ship's hull is submerged in seawater. This frictional resistance from seawater accounts for about 80% of the total resistance of a slow ship and about 50% of the total resistance of a high-speed ship.

[0003] The frictional resistance generated on the hull is due to the viscosity of the water particles that come into contact with the hull. Therefore, if a layer of material with a specific gravity smaller than that of water is formed between the hull and the water so as to block the viscosity of the water, the above-mentioned 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 ship's 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 far exceeds 100° C. However, such high-temperature and high-pressure gas has the problem of damaging the anti-rust and anti-fouling paint on the pipes that serve as the gas discharge passage and the surrounding members.

[0006] Furthermore, there is a problem that the gas and air discharged from the friction reduction device may flow into the sea chest of the ship, hindering the normal operation of the ship. Therefore, there is a need to develop a technology that can reduce the phenomenon of the 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 and high-pressure gas discharged from a friction reduction device.

[0008] Another object of the present invention is to provide a ship capable of reducing the phenomenon in which gas ejected from a friction reduction device flows into a sea chest. [Means for solving the problem]

[0009] To achieve the above-mentioned objective, a ship according to one embodiment of the present invention includes an equilibrium water tank provided on a 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 equilibrium water tank. Effect 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 the 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 description of the drawings]

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

[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] In addition, throughout the specification, when a certain component is "connected" to another component, it means that these components are not only "directly connected" but also "indirectly connected" through another component. Furthermore, when a certain component is "included," it does not mean that other components are excluded, but that other components may be further included, unless otherwise specified.

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

[0017] The ship 100 according to this embodiment includes a propulsion device required for operation. For example, the ship 100 includes a propeller 120 operated 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 in order to improve the operating speed or operating capacity of the ship 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 into a first balancing water tank 130 and a second balancing water tank 140 according to their locations. The first balancing water tank 130 is disposed 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 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 with respect to the keel of the hull 110 as shown in FIG. 2.

[0019] The vessel 100 includes a device capable of minimizing 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 jet 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, etc., disposed in each of the main pipe 220 and the auxiliary pipe 230.

[0021] The compressor 210 is disposed on the bow side of the hull 110 as shown in Fig. 1. Moreover, the compressor 210 is preferably disposed higher than the load waterline of the hull 110 for smooth generation of compressed air and for efficient operation. The compressor 210 is disposed between the pair of first balance water tanks 130 as shown in Fig. 2. However, the position of the compressor 210 is not limited to being 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 being overheated. Therefore, the compressed air flowing through the main pipe 220 can be cooled to 93°C or less, preferably 80°C or less, and moved toward the stern. Such cooling of the compressed air through the main pipe 220 can suppress or reduce damage to the anti-rust and anti-fouling paint formed on the main pipe 220, the auxiliary pipe 230, and the hull 110 caused by the overheated air.

[0023] The auxiliary pipe 230 is formed by branching off from the main pipe 220. As shown in FIG. 2, the auxiliary pipe 230 may branch off at a predetermined interval along the length of the main pipe 220 and then extend toward the stern. As shown in FIG. 2, the length in the line width direction of the auxiliary pipe 230 branching off from the main pipe 220 may be longer toward the stern. For example, the length in the line width direction of the first auxiliary pipe 230 branching off from the main pipe 220 may be smaller than the length in the line width direction of the second auxiliary pipe 230 branching off from the main pipe 220, and the length in the line width direction of the second auxiliary pipe 230 branching off from the main pipe 220 may be smaller than the length in the line width direction 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 so as to prevent a decrease in the gas injection pressure. In addition, the inner diameter of the auxiliary pipe 230 may be formed differently depending on the position at which it branches off from the main pipe 220. For example, the inner diameter of the auxiliary pipe 230 branching off first from the main pipe 220 may be larger than the inner diameter of the auxiliary pipe 230 branching off second from the main pipe 220, and the inner diameter of the auxiliary pipe 230 branching off second from the main pipe 220 may be larger than the inner diameter of the auxiliary pipe 230 branching off third from the main pipe 220. However, the inner diameters of all the auxiliary pipes 230 may be made the same if necessary.

[0024] The gas jet port 240 is connected to the auxiliary pipe 230. The gas jet port 240 is configured to jet the compressed air or compressed gas supplied via the auxiliary pipe 230 into seawater. Preferably, the gas jet port 240 can jet 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 jet port 240 is approximately parallel to the bottom surface of the hull 110.

[0025] In the ship 100 configured as described above, high-temperature and high-pressure air generated from the friction reduction device 200 is cooled while passing through the balance water tank, so that damage to piping caused by high-temperature compressed air can be minimized. In addition, since the ship 100 according to this embodiment cools the compressed air through the balance water tank, a separate device for cooling the compressed air can be omitted. Therefore, the ship according to this embodiment can not only reduce the construction cost, 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-mentioned embodiment are designated by the same reference numerals as those in the above-mentioned embodiment, and detailed description of these components will be omitted.

[0027] 4, the ship 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, 140 formed in the hull 110. Furthermore, the ship 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, 222. To supplement, the compressed air generated from the compressor 210 can be supplied to the respective gas jet ports 240, 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 balance water tank 130 and the first balance 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 reducing friction of the hull 110 by air jet. 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 improving the cooling efficiency by the balance water tanks 130, 132.

[0030] Next, a vessel according to still 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-mentioned embodiment are designated by the same reference numerals as those in the above-mentioned embodiment, 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 the ship 102 is configured with one balance water tank 130. Furthermore, the main pipe 220 is configured to vertically penetrate the center part of the balance water tank 130. For reference, this embodiment shows that one main pipe 220 vertically penetrates the balance water tank 130, but it may be modified so that two or more main pipes 220 penetrate the balance water tank 130 as necessary.

[0032] Next, a vessel according to still 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 are designated by the same reference numerals as those in the above-described embodiment, and description of these components will be omitted.

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

[0034] The auxiliary pipe 230 passes through the second balancing water tank 140 as shown in Figs. 10 and 11 so as to prevent overheating of the compressed air generated by the compressor 210. In addition, at least a portion of the auxiliary pipe 230 branching from the main pipe 220 can extend to the flat surface portion 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 93°C or less, preferably 80°C or less, and moved to the stern side. The cooling of the compressed air through the auxiliary pipe 230 in this manner can suppress or reduce damage to the anti-rust and anti-fouling paint formed inside the main pipe 220 and the auxiliary pipe 230 caused by the overheated air.

[0035] In the ship 103 configured as above, high-temperature and high-pressure air generated from the friction reduction device 200 is cooled while passing through the balance water tank, so that damage to piping caused by high-temperature compressed air can be minimized. In addition, in the ship 103 according to this embodiment, a separate device for cooling the compressed air can be omitted because the compressed air is cooled through the balance water tank. Therefore, the ship according to this embodiment can not only reduce the construction cost, 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 are designated by the same reference numerals as those in the above-described embodiment, and description of these components will be omitted.

[0037] 12, the ship 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, 140 formed in the hull 110. Furthermore, the ship 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] Supplementally, the compressed air generated from the compressor 210 may be supplied to the respective gas injection ports 240, 242 through 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 formed to pass through the first balancing water tank 130 and the first balancing 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 formed to pass through the second balancing water tanks 140, 142 so that the compressed air supplied through the main pipes 220, 222 can be secondarily cooled.

[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 of the hull 110 by air jet. Also, in the ship 102 according to this embodiment, the main pipes 220, 222 and the auxiliary pipes 230, 232 are cooled by the first balance water tanks 130, 132 and the second balance water tanks 140, 142, respectively, thereby improving the cooling efficiency by the balance water tanks 130, 132, 140, 142.

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

[0042] The gas jet ports 240 may be divided into a plurality of groups. More specifically, the gas jet ports 240 may be classified 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, in order from the bow side of the hull 110. The gas jet ports 241, 242, and 243 are arranged symmetrically with respect to the keel of the hull 110. The distance between the pair of gas jet ports 241 and 242 may gradually increase from the bow side of the hull 110 toward the stern. The gas jet ports 241 and 242 constituting the first and second groups are arranged so as not to overlap with the gas jet ports 241 and 242 arranged forward (based on the 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 be different 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 more 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 more than the numbers of gas injection ports 241, 243 constituting the first and third groups.

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

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

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

[0047] A distance L4 from the bisector or keel of the hull 110 to the gas jet port 2428 arranged at the outermost hull may be smaller than a 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] In addition, the ratio S3 / L between the keel and the distance S3 from the gas jet port 2428 arranged at the outermost hull to the sea chest 180 with respect to the length L of the hull 110 should be 0.5 or less. More preferably, S3 / L should be 0.48 or less.

[0049] The above conditions are effective in reducing the phenomenon in which gas or air discharged from the gas jets 241, 242, and 243 flows into the sea chest 180. Therefore, the ship 100 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 breakdown rate of the ship 100 caused thereby.

[0050] An arrangement of gas jet 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 jets.

[0052] The gas jet ports 240 may be divided into a plurality of groups. In addition, 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 in sequence from the bow side of the hull 110. The gas jet ports 241, 242 are arranged symmetrically about the keel of the hull 110. The distance between the pair of gas jet ports 241 may gradually increase from the bow side of the hull 110 toward the stern. 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 intervals between the paired gas injection ports 241, 242 may be different for each of the first and second groups. For example, the minimum interval W0 between the gas injection ports 2411 of the first group is smaller than the minimum interval W4 between the gas injection ports 2421 of the second group. The maximum interval W3 between the gas injection ports 2412 of the first group may be larger than the minimum interval W4 between the gas injection ports 2421 of the second group and larger than the maximum interval W5 between the gas injection ports 2422 of the second group.

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

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

[0057] A distance L4 from the bisector or keel of the hull 110 to the gas jet port 2422 arranged at the outermost hull may be smaller than a 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] In addition, the ratio S3 / L of the distance S3 from the gas jet port 2422 arranged at the outermost part from the keel to the sea chest 180 to the length L of the hull 110 is preferably 0.5 or less. More preferably, S3 / L is 0.48 or less.

[0059] The above conditions are effective in reducing the phenomenon in which the gas or air discharged from the gas jets 241, 242 flows into the sea chest 180. Therefore, the ship 105 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 breakdown rate of the ship 105 caused thereby.

[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 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 inclined angle θ1 may be larger than the second inclined angle θ2. For example, the first inclined angle θ1 may be 10 degrees or more, and the second inclined 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 larger than the length of the section forming the second inclined portion 2424. Also, the height Nh1 of the first inclined portion 2422 on the inclined surface of the main body 242 may be larger than the height Nh2 of the second inclined portion 2424. Such a 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. Additionally, the exhaust port 2442 is formed at the portion where the second inclined portion 2424 and the bottom portion 244 come into contact with each other.

[0063] The gas injection port 240 configured as described above can discharge the high-pressure air flowing in through the auxiliary pipe 230 approximately parallel to the surface of the hull (flat part of the bottom of the vessel) through the inclined parts 2422, 2424 and the discharge port 2442. Therefore, according to this embodiment, the frictional resistance between the surface of the hull 110 and seawater through 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, the same or similar components as the above-mentioned gas injection port will be designated by the same reference numerals as the above-mentioned gas injection port, 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-mentioned 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. Supplementally, 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. Supplementally, 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 portion 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 exhaust port 2442.

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

[0068] The gas injection port 2404 according to this embodiment is distinguished from the above-mentioned embodiment in that it further includes a second protruding portion 248 as shown in FIG. 6. The second protruding portion 248 is formed on the first protruding portion 246. Supplementally, the second protruding portion 248 may be formed at a second height h2 from the upper portion of the first protruding portion 246. The second height h2 of the second protruding portion 248 may be approximately the same as the height Nh1 of the first inclined portion 2422. However, the height h2 of the second protruding portion 248 is not necessarily the same as the height Nh1 of the first inclined portion 2422. For example, the height h2 of the second protruding portion 248 may be smaller than the height Nh1 of the first inclined portion 2422. The second protruding portion 248 has an inclined surface. Supplementally, one surface of the second protruding portion 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 multiple inclined portions 2422, 2424 and the 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 long time.

[0070] With reference to FIG. 23, still another embodiment of the gas injection port will be described.

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

[0072] With reference to FIG. 24, still another embodiment of the gas injection port will be described.

[0073] 8, the gas jet port 2406 according to this embodiment is distinguished from the above-mentioned embodiments in that the inclined surface of the main body 242 is composed of a plurality of curved portions 2422, 2424. Supplementally, the inclined surface may be composed of a first curved portion 2422 having a first curvature radius R1 and a second curved portion 2424 having a second curvature radius R2. Here, the first curvature radius R1 may be smaller than the second curvature radius 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-mentioned embodiment in that the inclined surface of the main body portion 242 is composed of a curved portion 2422 and a straight portion 2424. Supplementally, 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 now 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 operated 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 in order 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 that an internal combustion engine or the like disposed inside the hull 110 can be cooled.

[0079] The vessel 106 includes a device capable of minimizing frictional resistance between the hull 110 and saltwater 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 jet port 240. As shown in Fig. 26, the compressor 210 is disposed on the bow side of the hull 110. 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 long from the bottom of the sea chest 180 toward the bow of the hull 110, as shown in FIG.

[0082] The wing member 160 can be formed with 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 size.

[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 bent portion 162 bent downward as shown in FIG. 28. The wing member 160 may protrude from the hull 110 by a significant amount. For example, the protruding 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 caused by the gas of 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, the main pipes 220 may be provided in two pieces.

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

[0089] The gas jet port 240 is connected to the auxiliary pipe 230. The gas jet port 240 is configured to jet the compressed air supplied via the auxiliary pipe 230 into seawater. Preferably, the gas jet port 240 can jet the compressed air so that the compressed air flows along the surface of the hull 110 (specifically, the flat part of the bottom surface of the hull 110). 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 a plurality of groups. More specifically, the gas jet ports 240 may be classified 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, in order from the bow side of the hull 110. The gas jet ports 241, 242, and 243 are arranged symmetrically with respect to the keel of the hull 110. The distance between the pair of gas jet ports 241 and 242 may gradually increase from the bow side of the hull 110 toward the stern. The gas jet ports 241 and 242 constituting the first and second groups are arranged so as not to overlap with the gas jet ports 241 and 242 arranged forward (based on the 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 be different 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 more 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 more than the numbers of gas injection ports 241, 243 constituting the first and third groups.

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

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

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

[0096] A distance L4 from the bisector or keel of the hull 110 to the gas jet port 2428 arranged at the outermost hull may be smaller than a 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] In addition, the ratio S3 / L of the distance S3 from the gas jet port 2428 arranged at the outermost part from the keel to the sea chest 180 to the length L of the hull 110 is preferably 0.5 or less. More preferably, S3 / L is 0.48 or less.

[0098] The above conditions are effective in reducing the phenomenon in which the gas or air discharged from the gas jets 241, 242, and 243 flows 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 breakdown rate of the ship 106 caused thereby.

[0099] (Structure of the Carrier Ship According to the Present Invention) A vessel according to one embodiment will be described with reference to Figs. 32 to 34.

[0100] The vessel 107 according to this embodiment includes a propulsion device required for operation. For example, the vessel 107 includes a propeller 120 operated 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 in order to improve the operating speed or operating capacity of the vessel 107.

[0101] The vessel 107 includes a structure for transporting the 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 is formed on one or both sides of the liquefied substance storage tanks 430. A heating device 460 for maintaining the cofferdam 440 at a predetermined temperature may be disposed in the cofferdam 440.

[0102] The vessel 107 includes a device capable of minimizing frictional resistance between the hull 110 and saltwater 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 jet 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, etc., disposed in each of the main pipe 220 and the auxiliary pipe 230.

[0104] The compressor 210 is disposed on the bow side of the hull 110 as shown in Fig. 32. Moreover, 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 material storage tank 430 as shown in Figs. 2 and 3 in order to prevent the compressed air generated by the compressor 210 from being overheated. Therefore, the compressed air flowing through the main pipe 220 can be cooled to 93°C or less, preferably 80°C or less, and discharged to the gas jet port 240. Such cooling of the compressed air through the main pipe 220 can suppress or reduce damage to the paint (anti-rust paint and anti-fouling paint) of the pipes 220 and 230 caused by the overheated air.

[0106] The auxiliary pipe 230 is formed by branching off from the main pipe 220. As shown in FIG. 33, the auxiliary pipe 230 may branch off at a predetermined interval along the length of the main pipe 220 and then extend toward the stern. The length in the line width direction of the auxiliary pipe 230 branching off from the main pipe 220 may be longer toward the stern as shown in FIG. 2. For example, the length in the line width direction of the first auxiliary pipe 230 branching off from the main pipe 220 may be smaller than the length in the line width direction of the second auxiliary pipe 230 branching off from the main pipe 220, and the length in the line width direction of the second auxiliary pipe 230 branching off from the main pipe 220 may be shorter than the length in the line width direction 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 so as to prevent a decrease in the gas injection pressure. The inner diameter of the auxiliary pipe 230 may be formed differently depending on the position at which it branches off from the main pipe 220. For example, the inner diameter of the auxiliary pipe 230 branching off first from the main pipe 220 may be larger than the inner diameter of the auxiliary pipe 230 branching off second from the main pipe 220, and the inner diameter of the auxiliary pipe 230 branching off second from the main pipe 220 may be larger than the inner diameter of the auxiliary pipe 230 branching off third from the main pipe 220. However, the inner diameters of all the auxiliary pipes 230 may be made the same if necessary.

[0107] The gas jet port 240 is connected to the auxiliary pipe 230. The gas jet port 240 is configured to jet the compressed air or compressed gas supplied via the auxiliary pipe 230 into seawater. Preferably, the gas jet port 240 can jet 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 jet port 240 is 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 since high-temperature and high-pressure air generated from the friction reduction device 200 is cooled while passing through the cofferdam 440. Also, the ship 107 according to this embodiment can reduce power consumption required to heat the cofferdam 440 since the cofferdam 440 is heated by the compressed air of 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-mentioned embodiment will be designated by the same reference numerals as those in the above-mentioned embodiment, 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 a hull 110, a plurality of liquefied substance storage tanks 430 formed in the hull 110, and a cofferdam 440. Further, 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] In addition, 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 and then returns to the main pipe 220. The heat exchange pipe 470 is provided with a number of fin members 472 for improving heat dissipation efficiency. A number of valves 510 and 520 are disposed on the heat exchange pipe 470. Therefore, high-temperature and 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 operated to open when the temperature of the cofferdam 440 becomes lower than a preset temperature and to close when the temperature of the cofferdam 440 becomes higher than a preset temperature.

[0113] The ship 108 configured in this manner can significantly reduce power consumption for maintaining 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 still 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-mentioned embodiment are designated by the same reference numerals as those in the above-mentioned embodiment, 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-mentioned embodiments in that the high-temperature, high-pressure air flowing through the main piping 220 passes through at least one of the cofferdam 440 and the equilibrium water tank 570. For this reason, the main piping 220 is provided with a first heat exchange piping 470 branching off to the cofferdam 440 and a second heat exchange piping 480 branching off to the equilibrium water tank 570. The first heat exchange piping 470 and the second heat exchange piping 480 are provided with one or more valves 510, 520, 530, 340 for controlling the flow of air.

[0117] The ship 109 configured in this manner can pass the high-temperature, high-pressure air discharged from the friction reduction device 200 through the cofferdam 440, through the balance water tank 570, or through both the cofferdam 440 and the balance 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. 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 balance water tank 570.

[0118] 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 the piping caused by high-temperature, high-pressure air.

[0119] A vessel according to another embodiment will now be described with reference to FIG.

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

[0121] In this embodiment, the cofferdam 440 can be disposed as close as possible to the balancing water tank 570. For example, the cofferdam 440 may be disposed 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 piping 220 may be arranged to pass through an equalization water tank 570. Furthermore, the heat exchange piping 470 branching off from the main piping 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] The compressor 210 may be configured in a plurality. For example, the friction reduction device 200 according to the present 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 friction reduction device 200 according to the present embodiment can supply compressed air (or compressed gas) at a constant pressure and a constant flow rate to the gas injection port 240 by the remaining compressor 210. For reference, although the present embodiment shows that the three compressors 210 are connected in parallel, two or four or more compressors 210 may be connected in parallel as necessary.

[0128] Valves 720, 730, 760 are attached to the bypass pipe 206, the main pipe 220, and the auxiliary pipe 230. The valves 720, 730, 760 are connected to a control unit of the friction reduction device 200, and can operate to 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, 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 in operation. In contrast, the valves 710, 720, 730, 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 in operation.

[0129] 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 installed with a check valve 740 capable of blocking the inflow of seawater.

[0130] A valve control method for the friction reduction device 200 configured as above will be described below. The friction reduction device 200 can be operated in accordance with the operating state of the ship 100. For example, the friction reduction device 200 can be stopped when the ship 100 is anchored and can be operated 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 piping 206.

[0132] When the ship 100 is anchored, the friction reduction device 200 controls the valves 710, 720, 730, 740, and 760 so that the compressor 210 is not overloaded. In addition, the friction reduction device 200 stops the compressor 210 when it is detected that the ship 100 is anchored or the operating speed of the ship 100 is equal to or lower than 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, so 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 the pressure inside the auxiliary pipe 230 and the main pipe 220 constant. When the inflow of seawater is blocked through the auxiliary pipe 230 and the main pipe 220, the friction reduction device 200 opens the valve 760 of the bypass pipe 206 so that the pressure of the compressor 210 does not increase. For example, the friction reduction device 200 can open the valve 760 of the bypass pipe 206 when the internal pressure of the compressor 210 exceeds a set upper limit value. Thereafter, when the internal pressure of the compressor 210 falls below the set upper limit value, the friction reduction device 200 can stop the compressor 210 and close the valve 760.

[0133] The ship 100 configured as described above can improve the efficiency of the friction reduction device 200 by blocking the inflow of seawater through the bypass piping 206 and a number of valves and suppressing the overload phenomenon of the compressor 210.

[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 the pressure of the air supplied via the main pipe 220 can be measured. As another example, multiple pressure measuring devices 410 may be disposed in each auxiliary pipe 230.

[0137] The pressure gauge 410 can measure the pressure of air supplied to the main pipe 220 via the compressor 210. In addition, when the pressure gauge 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-mentioned examples, and a person having ordinary skill in the art to which the present invention pertains may make any number of modifications and variations within the scope of the technical ideas of the present invention as set forth in the following claims. For example, various features described in the above-mentioned embodiments may be combined and applied to other embodiments unless otherwise expressly described to the contrary.

Claims

1. In a ship equipped with a friction reduction device on the hull, 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; a bottom portion coupled to the body portion and having an outlet for injecting gas; The marine vessel, wherein the ramps are configured to have different slopes along a length of the ramps.

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

3. The vessel according to claim 2 , wherein a height Nh1 of the first inclined portion is greater than a height Nh2 of the second inclined portion.

4. The watercraft of claim 3 further comprising a first protrusion formed on the bottom.

5. The vessel according to claim 4 , wherein a height h1 of the first protrusion is smaller than a height Nh2 of the second inclined portion.

6. The watercraft according to claim 4 , wherein one surface of the first protrusion is formed to have an inclination.

7. The watercraft according to claim 4 , further comprising a second protrusion formed on an upper portion of the first protrusion.

8. In a ship equipped with a friction reduction device on the hull, 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 body portion having a curved portion; a bottom portion coupled to the body portion and having an outlet formed therein for injecting gas.

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

10. The watercraft according to claim 8 , wherein the body portion further includes an inclined portion connected to the curved portion and having a first inclination angle.

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