JP6011802B2 - Microbubble generating once-through pump device for friction reduction ship - Google Patents

Description

  The present invention reduces the frictional resistance of the hull during navigation by generating a large amount of microbubbles (fine bubbles) under the water surface on the bow side and covering the outer plate surface in contact with the side surface and bottom surface of the ship with microbubbles. The invention relates to a device for obtaining a high energy saving effect.

  Conventionally, as a 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 a thin slit provided on the ship outer plate on the bow side, a large number of jets and nozzles, etc. . 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. Further, Patent Document 5 also has a method in which a microbubble generating pump is installed on the outer plate of a ship to discharge the microbubbles along the hull.

  However, in any of the methods, it is difficult to provide a microbubble outlet and a slit in an existing hull. Moreover, it is not easy to attach the microbubble generating pump directly to the outer plate of the hull, and there is a problem of maintenance. In addition, the shape of the hull is various, and there is a problem that it is not possible to flexibly deal with the construction of jets and slits in the hull.

JP-A-9-156576 Japanese Patent Laid-Open No. 9-207873 Japanese Patent Laid-Open No. 11-49080 JP 2008-18781 A JP 2012-106542 A

  The conventional technology for generating microbubbles basically requires the construction of slits and jets in the hull outer plate, which is problematic in terms of cost and structure. In addition, it is difficult to perform additional work on the existing hull. Moreover, the method of directly fixing the microbubble generation pump to the hull outer plate under the water surface has problems in adjusting the installation position and maintenance. Therefore, the existing hull needs a structure that can use the microbubble generator for friction reduction and can easily adjust the installation position and perform maintenance.

  In order to solve the problems of the prior art, the present invention vertically installs a linear rail on the hull outer plate on the bow side from the outer plate of the upper deck to a predetermined position near the bottom of the ship below the water surface. This is a device configuration in which a microbubble generating once-through pump having a rectangular structure is attached to a slide plate that travels above. Since the pump can be set while being adjusted to an appropriate position below the water surface by rail running, it can be used for existing hulls, and the pump can run on the rail up and down, so maintenance is easy.

The structure of the once-through pump (cross flow pump) with a multi-blade cylindrical impeller is simply two-dimensional, so it is compactly assembled into a rectangular shape including the motor and installed on a slide plate that runs on the rail. Convenient and easy to install. Moreover, the range which covers the hull surface with microbubbles can be adjusted by simply changing the length of the impeller. In addition, since the discharge flow including the microbubbles from the pump contributes to the propulsion of the ship, there is no waste.

The method of setting the rectangular microbubble generating once-through pump of the present invention on the traveling linear rail attached to the hull outer plate can be installed in the existing ship relatively easily. is there. Since a large amount of microbubbles generated in the impeller of the once-through pump can be supplied along the surface of the hull along with a wide and stable discharge flow specific to the pump, the hull frictional resistance during navigation can be efficiently reduced. Also, maintenance can be performed efficiently because the pump can be lifted from the water by rail travel.

FIG. 1 is an installation diagram showing a basic overall configuration when the microbubble generating once-through pump 50 of the present invention is set on a traveling linear rail attached to a hull outer plate, and the state of the flow of microbubbles along the hull outer surface Indicates. Example 1 FIG. 2 is a cross-sectional plan view of FIG. 1 and shows the installation state and flow of microbubbles along the side skin of the ship when the microbubble generating once-through pump 50 is installed on the linear rail 30 installed on the side skin 70b of the ship. Shows the state. FIG. 3 is an enlarged cross-sectional view of the pump portion of the microbubble generating once-through pump 50 of FIG. 2 and shows the state of the flow of microbubbles along the outer surface of the hull. FIG. 4 is an installation diagram showing a basic overall configuration when a microbubble generating once-through pump 51 having a different form from that of Example 1 of FIG. 1 is installed at the bow, and shows the flow state of the microbubbles along the outer surface of the ship bottom. Show. (Example 2) FIG. 5 is a plan view of FIG. 4, showing the installation state and the state of microbubble flow along the outer surface of the ship bottom when the microbubble generating once-through pump 51 is installed on the linear rail 30 installed on the outer plate of the hull port side. . FIG. 6 is an enlarged cross-sectional view of the pump portion of the microbubble generating once-through pump 51 of FIG. 4 and shows the state of the flow of microbubbles along the outer surface of the ship bottom. FIG. 7A is a cross-sectional view of the impeller portion of the microbubble generating through-flow pumps 50 and 51, and shows a jetting state J from the air diffuser type nozzle. (B) shows the ejection state J2 from the front-end | tip of the cylindrical nozzle in another form. FIG. 8 shows the detailed structure of the gas-liquid mixing chamber. (A) is a double pipe structure type, (b) is a nozzle jet type

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

FIG. 1 is a first embodiment, and shows an overall configuration relating to the invention of claim 1. 2 is a plan sectional view of FIG. 1, and FIG. 3 is an enlarged view of the pump portion of FIG. In FIG. 1, a linear rail 30 is vertically installed on a side shell of a ship on the bow side from a skin of an upper deck portion to a predetermined position near a bottom of a ship below the water surface, and a slide plate 31 traveling on the linear rail 30. The microbubble generating once-through pump 50 is attached to the pump, and two pumps can be set while adjusting to an appropriate position below the water surface. Since the structure of the once-through pump having the cylindrical multi-blade impeller 7 is simple and two-dimensional as described above, the entire structure including the submersible motor 12 is compactly collected in a rectangular shape. Therefore, the slide plate 31 that travels on the rails. Can be conveniently and easily attached. Also, during maintenance, it is advantageous because the pump can be easily lifted onto the water surface by rail running. If the slide plate 31 is self-propelled, the working efficiency is improved.

According to this embodiment, the flow of the once-through pump can obtain a two-dimensional, wide, stable and uniform flow and the Coanda effect (the effect of the flow flowing along the object surface). Since the flow of the microbubbles discharged from the once-through pump 50 flows along the side surface outer plate 70b of the ship as shown in FIG. 3, the hull can be covered with a thin layer of microbubbles. In order to make the Coanda effect effective, the flow velocity of the discharge flow D shown in FIG. 3 needs to be higher than the velocity of the external flow F (flow passing through the vicinity of the ship body related to the ship speed and the ocean current).

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, since the discharge flow including the microbubbles can be supplied in a sheet shape along the hull surface and the Coanda effect can be surely covered the boundary layer, the efficiency is high. In addition, by properly arranging the casing shape including the suction port and the discharge port of the two-dimensional cross-flow pump main body, the structure of the tongue portion 8 and the length of the impeller, the state of the flow corresponding to the shape of the hull It has an excellent feature that can be obtained.

As shown in FIG. 1, the generation of microbubbles generated in the impeller includes a microbubble mixed liquid generated by merging gas and liquid in a gas-liquid mixing chamber 40 (details will be described later) into a pressure pump 42. The microbubble-containing pressurized liquid that is refined and pressurized while rotating and stirring is supplied to the air diffuser type nozzle 3 inserted into the impeller shown in FIG. The supplied pressurized liquid containing fine bubbles is jetted into the rotating impeller 7 from the jet outlet into the rotating impeller 7, depressurized, and mixed with the flow in the impeller to form microbubbles. As a result, it flows out from the pump outlet along the hull surface.

FIG. 4 shows the overall configuration of another embodiment of the second embodiment which is different from the first embodiment of FIG. 5 is a plan view of FIG. 4, and FIG. 6 is an enlarged cross-sectional view of the pump portion of FIG. As shown in FIGS. 4 and 5, the linear rail 30 is vertically installed on the hull outer plate of the bow port part from the upper deck outer plate to the vicinity of the bottom of the ship below the surface of the water, and on the slide plate 31 that runs on the linear rail 30. A microbubble generating once-through pump 51 is attached and set at the bottom of the ship. The shapes and directions of the casings of the suction port 21 and the discharge port 22 of the pump are arranged so that the flow follows the ship lower surface 70c as shown in FIG. The basic device configuration relating to the generation of microbubbles is the same as in the previous embodiment.

According to this embodiment, as shown in FIGS. 4 and 6, the flow of microbubbles discharged from the microbubble generating once-through pump 51 flows along the outer plate surface 70 c of the ship bottom by the Coanda effect and covers the ship bottom surface. Therefore, friction is reduced.

In the above embodiment, the microbubble generating once-through pump 50 is used separately for the side of the ship, and the microbubble generating once-through pump 51 is used separately for the bottom, but the Coanda effect (flow is along the surface of the hull is not required). The microbubble once-through pump is set at an appropriate position on the bow, and the shape of the hull surface near the discharge port is locally changed. By doing so, it is possible to respond flexibly so that the surface of the hull including both the side surface and the bottom surface of the ship can be covered with microbubbles.

The sizes of the microbubble generating through-flow pumps 50 and 51 depicted in FIGS. 1 to 6 are depicted at a large ratio with respect to the hull, unlike actual ones, for easy understanding. Basically, it is sufficient to cover the thin boundary layer on the surface of the hull with a microbubble flow as described above, so the size of the impeller diameter of the pump may be about 8 cm to 20 cm, although it depends on the size of the ship. It is done. The size and number of pumps vary depending on the size of the ship.

FIG. 7A is a detailed cross-sectional view of the impeller part. The fine bubble-containing additive pressurized by the pressure pump 42 shown in FIGS. 1 and 4 is applied to the air diffuser type nozzle 3 inserted into the impeller 7. A state in which the pressurized liquid is press-fitted through the pipe 13 and ejected and diffused from the small hole 5 of the nozzle is shown. In this case, since the nozzle 3 is fitted in the impeller hollow rotating shaft 16 and rotates integrally with the impeller, the nozzle 3 is efficiently miniaturized by diffusion of the jet flow accompanied by rotation and mixing of the flow in the impeller. Microbubbles are obtained. FIG. (B) shows the configuration of the cylindrical type nozzle and the ejection state J2 from the nozzle. The cylindrical type nozzle in this case does not rotate, but the basic microbubble generation mechanism is the same as in FIG.

FIG. 8 shows a detailed configuration example of the gas-liquid mixing chamber 40 shown in FIGS. FIG. 8A shows a gas-liquid mixing chamber 43 of a double tube structure type, in which gas is supplied to the gap between the inner tube 44 and the outer tube 45, and the inside of the inner tube 44 through a large number of small holes 46 opened in the inner tube 44. Basically, a fine bubble mixture is obtained by blowing gas into the water flow passing through the. FIG. 8 (b) shows a nozzle jet type gas-liquid mixing chamber 47, in which a fine gas-liquid mixture is obtained by jetting gas into the water stream from a nozzle 48 inserted in the center of the pipe of the upstream contraction section. Basic.

The microbubble generating once-through pump device for friction reduction set on the linear rail of the present invention can be installed and installed relatively easily on existing ships, and it is a wide and stable one due to the flow characteristics peculiar to a rectangular structure once-through pump. With such a discharge flow, the hull surface can be efficiently covered with microbubbles, which is effective in reducing friction during navigation. Further, since the pump can run on the rail, it is advantageous for adjustment of the installation position and maintenance.

3 Nozzle type nozzle 5 Small hole (ejection hole)
6 Blade 7 Cross-flow pump impeller 8 Casing tongue 10 Tubular type nozzle 12 Submersible motor 13 Hose 14 Water surface 16 Impeller hollow rotary shaft 21 Pump suction casing 22 Pump discharge casing 25, 26 Impeller Hollow shaft bearing 30 Linear rail 31 Slide plate 40 Gas-liquid mixing chamber 42 Pressure pump 43 Gas-liquid mixing chamber 44 of double-pipe structure type Gas-liquid mixing chamber inner tube 45 Gas-liquid mixing chamber outer tube 46 Small hole (gas Blow hole)
47 Nozzle jet type gas-liquid mixing chamber 48 Nozzle (for gas ejection)
50, 51 Micro-bubble generating once-through pump
70 Ship 70b Ship side skin 70c Ship bottom skin
B Fine bubbles
D Flow of microbubbles flowing out from the pump outlet along the hull surface
F Outer current (flow past the hull near the ship's speed and current)
J, J2 Fine bubble flow ejected from nozzle

Claims (1)

A linear rail is installed vertically on the side shell on the bow side from the outer plate of the upper deck to a predetermined position near the bottom of the ship, and a cylindrical, multi-blade impeller is installed on the slide plate that runs on the rail. Install a rectangular microbubble generating once-through pump having a fine bubble generating mechanism at the center of the impeller so that it can run up and down, and set the pump at an appropriate position below the water surface while adjusting the pump. The microbubble generating once-through pump device for a friction-reducing ship, characterized in that the discharge flow of microbubbles flows along the hull surface

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