JP5651829B2 - Friction reduction ship and micro bubble generation pump - Google Patents

Description

  The present invention generates a large amount of microbubbles (fine bubbles) under the water surface on the bow side and covers the outer plate surface in contact with water on the bottom and side surfaces of the ship with fine bubbles, thereby reducing the frictional resistance of the hull during navigation. The present invention relates to a device that reduces and obtains a high energy saving effect.

  Conventionally, as means for reducing the frictional resistance by covering the surface of the hull with microbubbles, there is a method in which air is blown out by thin slits provided on the bow side, a large number of jets and nozzles. For example, Patent Document 1 discloses that the outlet is slit-shaped, Patent Document 2 and Patent Document 3 that disclose many nozzle shapes, and Patent Document 4 that discloses the nozzle shape.

There are various shapes of air outlets, but in any case, the diameter of the discharged air bubbles is not very small, and the influence of the ascending speed is large, and the flow caused by the blowout is turbulent, causing separation and flowing along the hull. There are problems such as difficulty. In particular, when there is a spout on the side of the ship, the blown out bubbles are also affected by buoyancy and turbulence, and it is difficult to stably cover the side of the ship with the bubble flow to the stern. Accordingly, it is difficult to obtain a remarkable energy saving effect by microbubbles.

    According to Non-Patent Document 1, since it is difficult to make the particle size of the blowing bubbles small, the influence of the buoyancy of the bubbles is large. In the air blowing method from a thin slit provided on the bow on the bow side, Because the blown bubbles are unstable and may cause separation, it is difficult to stably cover the bottom of the ship to the stern. For this reason, an end plate is provided on the outside of the bottom shell plate to suppress the outflow of bubbles from the side of the bottom. Is shown.

JP-A-9-156576 Japanese Patent Laid-Open No. 9-207873 Japanese Patent Laid-Open No. 11-49080 JP 2008-18781 A Kodama Yoshiaki “Toward the Practical Use of Ship Lubrication Reduction Technology by Air Lubrication”, Journal of the Japan Society of Mechanical Engineers, 112-1086 (2009-5), 46-49.

  In the conventional microbubble generation technology, the bubbles are not sufficiently refined, the flying speed is high, and the efficiency is low. In addition, a stable microbubble flow cannot be obtained. In order to solve these problems, a friction reduction technique capable of stably supplying a bubble flow as a flow along the surface of the hull together with a generator capable of obtaining finer bubbles is required.

  In the present invention, in order to solve the problems of the prior art, a novel once-through pump (cross flow pump) developed for generating microbubbles is installed under the water surface on the bow side. A large amount of microbubbles generated inside the once-through pump is discharged while being uniformly mixed in the flow inside the pump. Due to the flow characteristics unique to the once-through pump, this discharge bubble flow containing a large amount of microbubbles becomes a wide, laminar flow that is uniform and less disturbed at the discharge part, and the flow flows to the stern along the hull surface. A stable flow is formed and the hull is covered with microbubbles. In this way, friction can be reduced efficiently.

FIG. 1 shows a cross-sectional view of a cross-flow pump main body developed in this patent. (A) is a cross-sectional view of a cross-flow pump (cross-flow pump) main body 50, and (b) is a cross-sectional view taken along the line YY of (a), showing a microbubble generating pump 55. The cross-flow pump body 50 basically includes a casing 30 that houses a cylindrical multi-blade impeller 7, and a hollow rotary shaft 3 that has a tongue 8 that controls the flow and a diffuser hole 5. The microbubble generating pump 55 includes an air pump 11 and a liquid pump 11 b connected by a hose 13 for supplying air and the like to the cross-flow pump body 50, and a driving motor 12 connected to the hollow rotary shaft 3.

The flow passes through the blade 6 twice from the suction side 9 toward the discharge side 10 as shown in the pump sectional view of FIG. That is, the flow flows from the outside of the impeller 7 to the inside on the suction side 9 and flows out from the inside to the outside on the discharge side 10 to cross the impeller 7. Since the impeller 7 can be long in the width direction, and the flow is discharged tangentially to the impeller, the discharge flow is a wide sheet, less turbulent, and does not diffuse, unlike the prior art. Therefore, the flow of micro bubbles spreads along the hull surface from the bow side toward the stern.

Further, since the inlet and outlet of the blade 6 on the suction side are reversed on the discharge side, it is an excellent strength in operation that an object is not easily clogged between the blades.

As shown in FIGS. 1 (a) and 1 (b), the structure for generating fine bubbles is such that a large number of diffused holes 5 are constricted on the outer peripheral surface of the hollow rotary shaft 3 in the impeller 7, or an additional porous material. Gas and liquid can be supplied by the air pump 11 and the liquid pump 11b connected to the hose 13 outside the impeller through the hollow rotating shaft 3. The gas supplied from the outside into the impeller is discharged as a bubble by the ejection indicated by S from the diffuser hole 5 of the hollow rotary shaft 3, but the bubble is discharged from the diffuser hole 5 with rotation. Therefore, the bubbles have a minute diameter due to the effect accompanying rotation, and are further subdivided by passing between the rotating blades 6 to be discharged as ideal minute bubbles and discharged along the hull surface together with the water flow. . The smaller the number of revolutions, the finer. The method for supplying bubbles from the diffuser holes 5 of the hollow shaft 3 in the rotating impeller 7 is excellent as a method for obtaining uniform and uniform fine bubbles.

The liquid pump 11b is for injecting a chemical solution in order to prevent shells or the like from attaching to the once-through pump, or for injecting a cleaning solution when cleaning the inside of the pump.

FIG. 2 shows an example in which an air dispersion generator 17 is installed on the pump suction side 9. The gas is supplied to the air dispersion generator 17 by the air pump 11 as in FIG. In this case, most of the bubbles released from the air dispersion generator 17 pass through the blades 6 and cross the impeller 7 twice from the suction side 9 toward the discharge side 10 together with the flow. Since the bubbles are subdivided every time they pass through the rotating blade 6, fine bubbles are obtained on the discharge side. The air dispersion generator 17 may be attached to the discharge side of the pump or attached to the casing wall surface, but it is difficult to obtain uniform fine bubbles.

3 and 4 show a technique for further reducing the diameter of the bubbles released from the air holes 5. FIG. FIG. 3 shows a structure in which a large number of small rod-shaped protrusions 28 protrude radially on the outer peripheral surface of the hollow rotary shaft 3 having the air diffusion holes of the once-through pump impeller 7, and FIG. It is characterized in that it has a structure in which several elongated pipe-shaped rods 29 are arranged in parallel and substantially concentric with the hollow rotary shaft 3 and are arranged in the impeller width direction. Along with the rotation of the impeller, the wake turbulence of the two kinds of rod-shaped bodies is further miniaturized by locally disturbing the bubbles released from the diffuser holes 5 and discharged along the hull surface from the pump discharge port. Will be.

  In order to reduce the frictional resistance, basically, a thin boundary layer on the surface of the hull below the water surface may be covered with microbubbles. In the present invention, the boundary layer is reliably covered by the Coanda effect (the effect that the flow flows along the curved surface of the object surface) and the discharge flow including the microbubbles can be supplied in a sheet shape along the surface of the hull. Can be efficient. In addition, it has the excellent feature that the shape of the hull shape can be obtained by appropriately arranging the casing shape and the tongue structure including the suction port and discharge port of the cross-flow pump body. Yes.

Moreover, since the discharge flow including fine bubbles from the pump can contribute to the propulsion of the ship, there is no waste.

According to the microbubble generating pump of the present invention, it is possible to supply a wide, sheet-like and stable flow including fine bubbles, which cannot be obtained by the prior art, along the hull surface. It can contribute as a technology to reduce frictional resistance efficiently.

FIG. 1 shows the basic structure of a microbubble generating pump according to the present invention. (A) is sectional drawing which shows the structure of a once-through pump main body, (b) is sectional drawing of the micro bubble generation | occurrence | production pump of the (Y) arrow YY. FIG. 2 shows a basic structure of a microbubble generating pump of another form different from FIG. (A) is sectional drawing which shows the structure of a once-through pump main body, (b) is sectional drawing of the micro bubble generation | occurrence | production pump of the (Y) arrow YY. FIG. 3A is a cross-sectional view showing a structure in which a large number of rod-like small protrusions protrude radially on the outer peripheral surface of a hollow rotary shaft having an air diffuser hole of an impeller, and FIG. 3B is a view taken along the line YY in FIG. FIG. 4A is a cross-sectional view showing a structure in which several elongated pipe-like rods are arranged in a substantially concentric manner parallel to the rotation axis and are passed in the width direction of the impeller, and FIG. It is impeller sectional drawing of -Y arrow. FIG. 5 shows an installed state of the friction-reducing ship when a plurality of microbubble generating pumps are connected to the side and bottom of the ship at the bow. (A) is a plane sectional view showing the state where the bubble flow discharged from the pump flows along the surface of the hull, and (b) is a side view. Example 1 FIG. 6 is an enlarged cross-sectional view of the pump portion of the microbubble generating pump 55b shown in FIG. FIG. 7 is an enlarged cross-sectional view of the pump portion of the microbubble generating pump 55c in FIG. FIG. 8 shows a form of a friction reducing ship when a plurality of microbubble generating pumps are connected to a ship 71 having a different form from that of the first embodiment shown in FIG. (A) is a plane sectional view showing the state of bubble flow which flows along the surface of a hull, and (b) is a side view. (Example 2) FIG. 9 is an enlarged sectional view of the pump portion of the microbubble generating pump 55d shown in FIG. FIG. 10 is an enlarged cross-sectional view of the pump portion of the microbubble generating pump 55e shown in FIG. FIG. 11 shows a form in which four integrated microbubble generating pumps connected with impellers are installed on the side and bottom of the ship. (A) is a plane sectional view showing the state where the bubble flow discharged from the pump flows along the surface of the hull, and (b) is a side view. (Example 3) FIG. 12 shows an enlarged view of the pump portion of the microbubble generating pump 55f (55g) of FIG. FIG. 13 shows a configuration in which a micro-bubble generating pump 55h in which three pumps are connected is installed in the ship, and a water intake port and a discharge port are opened to the outside through the hull outer plate. (A) is a plane sectional view showing the state of the flow containing fine bubbles, and (b) is a side view. Example 4 FIG. 14 shows a configuration in which the microbubble generating pump 55i is installed on the bottom of the ship, and the water intake and discharge are opened to the outside through the ship bottom outer plate. (A) is sectional drawing which shows the installation state of an apparatus and the state of the flow containing a microbubble, (b) is a YY arrow directional view. (Example 5)

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 5 is a first embodiment of the present invention, and shows a form of a friction reducing ship 80 when the microbubble generating pump 55b according to claim 1 is set on the ship 70 and integrated. (A) is a plane sectional view, (b) is a side view. In the present invention, two micro-bubble generating pumps 55b in which two pumps are connected to the port and starboard skins of the ship under the water surface of the bow, and two pumps are connected to both ends of the underwater motor 12b on the ship's outer skin. A microbubble generating pump 55c is installed. 6 and 7 show enlarged sectional views of the microbubble generating pumps 55b and 55c. The enlarged view of FIGS. 5, 6, and 7 shows a state in which a flow including a large amount of microbubbles flows along the hull surface. Air is supplied from the air pump 11 to the hollow rotating shaft 3 of the microbubble generating pumps 55b and 55c shown in FIGS. 6 and 7 as in FIG. The air bubbles 5 are perforated on the outer periphery of the shaft and are discharged as fine bubbles while rotating, discharged together with the flow, and supplied as a bubble flow.

According to this embodiment, as shown in FIG. 5 (a), the discharge flow containing the microbubbles generated in the pump of the microbubble generating pump 55b installed on the port side and the outer shell of the starboard is the Coanda. The effect (the flow flows along the surface of the object) flows along the curved hull surface. Due to the characteristics of the once-through pump, the discharge flow containing fine bubbles can be extended to a long distance as a uniform flow without diffusing due to its wide sheet shape. Therefore, since the hull surface can be covered with fine bubbles from the bow side to the stern, the frictional resistance can be reduced efficiently. A flow including fine bubbles discharged from the pump of the microbubble generating pump 55c installed on the outer plate of the ship bottom can cover the surface of the hull with the fine bubble flow in the same manner.

In order to reduce the frictional resistance, basically, the thin boundary layer where the hull surface is in contact with water may be covered with bubbles as described above, and it is not necessary to cover with a thick layer. Accordingly, the discharge flow D of the once-through pump is convenient because it is wide as described above and is less disturbed and can reach a long distance as a uniform flow without spreading. The outflow speed from the pump discharge port can be increased or decreased by changing the number of revolutions of the pump, so the discharge flow is most difficult to diffuse in relation to the external flow F (the flow passing through the vicinity of the hull and related to the ship speed and ocean current). Set to speed. In any case, in order to make the Coanda effect effective, the flow velocity of the discharge flow D needs to be higher than the velocity of the external flow F.

The sizes of the microbubble generating pumps 55b and 55c depicted in FIG. 5 are depicted at a large ratio with respect to the hull, unlike the actual case, for easy understanding. Basically, since the thin boundary layer on the surface of the hull may be covered with microbubbles, the size of the blade diameter of the pump is considered to be about 10 cm to 20 cm although it depends on the size of the ship. The size and number of pumps and the combination of driving motors vary depending on the size of the ship.

When the liquid pump 11b prevents shells from attaching to the pump as described above, or when cleaning the inside of the pump, the liquid pump 11b supplies chemical liquid or cleaning liquid through the hose 13 into the pump. Used for.

FIG. 8 is a second embodiment of the present invention, and shows a form of a friction reducing ship 81 when the microbubble generating pump according to claim 1 is set on a ship and integrated. (A) is a plane sectional view, (b) is a side view. The structure of the ship is such that depressions 75 and 75b for housing and installing the microbubble generating pumps 55d and 55e are provided on the outer plate of the hull. The pump 55d is installed by connecting two pumps to the outer plate of the depression 75 on the port side of the bow and starboard, and the pump 55e is attached to the outer plate of the depression 75b on the bottom of the boat on both ends of the underwater motor 12b. The case where two pumps are connected and installed is shown. The combination of the number of pumps and the number of motors varies depending on the size of the ship.

A screen 35 for dust removal is installed immediately upstream of the suction port of the pump. As described above, the once-through pump has a structure in which things are not easily clogged between the blades, so that the screen mesh may be rough to some extent. In the following embodiments, the dust screen is omitted.

According to this embodiment, since the microbubble generating pumps 55d and 55e do not protrude from the hull outer plate, the pump body does not become an obstacle to the flow, so that the flow of fine bubbles is smooth along the hull surface. -It can be flushed. Further, the screen 35 can prevent the floating material such as dust and jellyfish from entering the suction port. The reason why the screen 35 is attached obliquely along the hull is to make it easier for dust to flow backward.

Note that the microbubble generating pump 55b installed on the outer plate of the ship's abdomen is for enhancing fine bubbles in the middle when the length of the hull such as a tanker is large, but the pump is not installed in the recess. The pump body protrudes from the outer plate. In this case, a reinforcement frame is required to prevent damage such as when the ship is on the shore.

9 and 10 are enlarged cross-sectional views showing a state where the microbubble generating pumps 55d and 55e are installed and a state in which a flow including fine bubbles flows out along the hull surface. In both cases, the casing shape is arranged so that the direction of the suction port and the discharge port of the pump is along the hull. In particular, it is necessary to pay close attention to the flow direction from the discharge port so that the flow containing fine bubbles follows the hull surface. Further, the flow rate of the pump discharge flow D needs to be faster than that of the external flow F as described above. The discharge flow rate is performed by changing the rotation speed of the pump. The generation mechanism of the fine bubbles is the same as in the first embodiment.

FIG. 11 shows a third embodiment of the present invention. Unlike the first embodiment, the microbubble generating pumps 55f and 55g, in which four impellers 7 are integrated continuously, are connected to the ship side and bottom skins on the bow side. The form of the friction reduction ship 82 when installed in FIG. (A) is a plane sectional view, (b) is a side view. The shape and direction of the pump outlet are arranged so that a flow containing fine bubbles flows along the hull surface. FIG. 12 is an enlarged view showing the structure of the microbubble generating pump 55f (55g). The generation mechanism of the fine bubbles and the state in which the flow including the fine bubbles is released along the surface of the hull are the same as in the first embodiment.

FIG. 13 shows a fourth embodiment of the present invention, in which the main body of a micro-bubble generating pump 55h connected with three pumps is installed in a ship, and a water intake 42 and a discharge opening 43 are opened to the outside through a shipboard outer plate. (A) is a plane sectional view, (b) is a side view. As shown in FIG. 5A, the flow is taken into the tank 40 from the outside of the ship through the water intake port 42 and discharged from the discharge port 43 through the microbubble generation pump 55h connected to the tank 40. The fine bubbles are generated inside the impeller 7 as described above, and the flow containing the fine bubbles flows out from the discharge port 43 through the discharge duct 47 along the surface of the hull. The shapes of the discharge duct 47 and the discharge port 43 are adjusted so that a flow including fine bubbles flows along the hull surface. In this structure, since the pump is installed in the ship, it does not hinder the flow, is not directly affected by dust, and is convenient for maintenance of the pump.

FIG. 14 shows a fifth embodiment of the present invention, in which the main body of the microbubble generating pump 55i is installed on the bottom of the ship, and the water intake 42 and the discharge port 43 are opened to the outside through the ship bottom outer plate. (A) is sectional drawing which shows the installation state of an apparatus, (b) is a YY arrow directional view, and is the top view which drew half of the symmetrical drawing. The configuration of the apparatus is basically the same as that of the fourth embodiment shown in FIG. 13. The flow is taken into the tank 40 b from the outside through the water intake 42, discharged from the microbubble generation pump 55 i connected to the tank 40 b, and discharged through the duct 47. From 43, it is structured to discharge out of the ship. In the present embodiment, on the bottom of the ship, a flow including fine bubbles flows from the discharge port 43 along the surface of the hull so that the ship bottom surface can be covered with the fine bubbles.

  The technology of the microbubble generating pump of the present invention supplies a flow including a large amount of fine bubbles generated through the air diffuser of the hollow rotating shaft in the impeller as a wide and sheet-like stable discharge flow along the hull surface. In addition, since the surface of the hull can be covered with microbubbles, it is effective for reducing friction during navigation of the ship.

3 Impeller hollow rotary shafts 5, 5 b having air diffusion holes 6 Air diffusion holes 6 Blades 7 Cross-flow pump impeller 8 Casing tongue 9 Pump suction side 10 Pump discharge side 11 Air pump 11 b Liquid pump 12 Motor 12 b Drive water Medium motor 13 Hose 14 Water surface 17 Air dispersion generator 28 Rod-shaped small protrusions 29 projecting radially from the outer peripheral surface of the hollow rotating shaft 3 Elongated pipes installed across the width of the impeller parallel to the hollow rotating shaft 3 Shaped rods 30, 30b Pump casing 35 Dust removal screen 40, 40b Tank 41 Water intake pipe 42 Water intake port 43 Pump discharge port
45 Water intake valve 46 Discharge valve 47 Discharge duct 50 Cross-flow pump body 55, 55b, 55c, 55d, 55e, 55f, 55g, 55h, 55i Micro bubble generating pump
70,71 ship 75 screw
80, 81, 82, 83, 84 Friction reduction ship
B Microbubble
D Flow containing microbubbles flowing out from the pump discharge port along the hull surface
F Outer current (flow past the hull near the ship's speed and current)
S Flow that flows out as fine bubbles (liquid) from the diffuser holes 5 and 5b

Claims (1)

Flow pump multiblade impeller shape is cylindrical (Kurosufuro - pump) and the axis of rotation of the impeller into the hollow, piercing a large number of diffusing pores on the outer peripheral surface of the impeller in the rotation axis, or the additional porous material The structure is affixed so that air can be supplied from the outside of the impeller through the hose connected to the hollow rotating shaft to the center of the impeller, and fine bubbles are ejected into the impeller while rotating from the air diffuser . A once-through pump with a micro-bubble generating mechanism is installed on the outer plate on the side or bottom of the hull under the water surface on the bow side, and the discharge tank including the suction port is placed so that the discharge flow containing fine bubbles follows the hull surface toward the stern. -Friction-reducing ship and micro-bubble generating pump characterized by the arrangement of a single shape

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