JPH11227675A - Air blowout apparatus of vessel with reduced frictional resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the man-hours in works to perform installation. SOLUTION: In a ship bottom strake 1 where longitudinals 10 are installed, a number of air blowoff parts 3 are furnished in such a way as arranged in line across the hull width. A sea chest 11 stretching continuously in the direction across the hull width is attached to the inside of the side strake 1 so that the air blowoff parts 3 are put in communications. The sea chest 11 strides the longitudinals 10 by threading them 10 through notches 12. An air supplying pipe 13 is connected with the sea chest 11. The pressurized air fed into the sea chest 11 through the pipe 13 is dispersed in the direction across the width and blown off to outside the ship from the air blowoff parts 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air blower for a frictional resistance reducing ship in which the hull surface is covered with microbubbles in order to reduce the frictional resistance acting on the hull surface during navigation. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air blower of a ship for reducing frictional resistance in which a ship bottom is widely covered with bubbles.

[0002]

2. Description of the Related Art During the navigation of a ship, a boundary layer of seawater is formed around the hull due to the viscosity of seawater as a fluid. In this boundary layer, the flow velocity of the seawater is zero and the hull surface is zero. It tends to change drastically as the distance from the surface increases, and seawater frictional resistance acts on the surface of the hull, which is one of the major factors of hull resistance.

[0003] Therefore, in recent years, studies have been made to improve the propulsion performance by reducing the frictional resistance acting on the surface of the hull, and as one of the measures, micro-bubbles (micro-bubbles) are generated from the hull surface. And blow the microbubbles into the boundary layer of the submerged part (submerged part) of the hull to cover the submerged surface of the hull with the microbubbles, thereby reducing the frictional resistance acting on the hull surface. Research on the microbubble propulsion method is ongoing.

[0004] As one method of realizing the microbubble propulsion method, pressurized air generated by an air supply device such as a compressor is blown out from the bottom of a ship into water to form required voids by microbubbles on the bottom of the ship. It is thought to be. As means for blowing out the pressurized air from the bottom of the ship, as shown schematically in FIGS. 4 (a) and 4 (b), an opening 4 is formed in the bottom shell 1 and a large number of openings are formed in the opening 4. A perforated plate 6 in which air outlets (pores) 5 are perforated at a required pitch is attached to form an air outlet 3, and the air outlet 3 is not shown so as to surround the air outlet 3. A sea chest 7 connected to an air feeding device via an air feeding pipe 8 is attached to the inside of the hull bottom plate 1 in a watertight manner, and the sea chest 7 is passed through the air feeding pipe 8 from the air feeding device. An air blowing device 2 has been proposed in which the supplied pressurized air is blown into water from an air blowing port 5 of the air blowing section 3 to generate micro bubbles.

[0005] As the air blowing portion 3 of the air blowing device 2, as shown in FIG. 5 (a), a porous plate 9 is attached to the opening 4 similar to the above, or as shown in FIG. 5 (b). As described above, there has been proposed an air blower 2 of a type in which a large number of air blowout ports 5 are formed directly on the bottom shell 1 and a group of these air blowout ports 5 is used as an air blowout section 3.

[0006]

However, FIG. 4 (a)
In the conventional air blower 2 proposed in (b) and FIGS. 5 (a) and (b), in order to be able to cover the bottom of the ship widely by carrying the flow of seawater during navigation, FIG.
As shown in the figure, the air blowing section 3 is provided at a position between each of the longes 10 on the bottom of the ship, and the sea chest 7 is attached to each of the air blowing sections 3. There is also a problem that the number of supply pipes 8 is increased, the number of work steps is increased, installation work becomes difficult, and the installation cost increases.

Accordingly, an object of the present invention is to provide an air blower for a frictional resistance reducing ship which can be easily installed with a small number of work steps so as to reduce the installation cost.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a large number of air blowers for generating fine air bubbles by blowing pressurized air into water on a bottom plate of a ship. Are arranged in the hull width direction,
A common sea chest for guiding the pressurized air supplied through the air supply pipe to each of the air blowing portions is assembled in the hull width direction on the inner side of the hull bottom outer plate so as to straddle the longitudinal of the hull bottom. Configuration.

The pressurized air supplied into the sea chest through the air supply pipe is distributed in the hull width direction in the sea chest, and is led to the respective air blowing portions arranged in the hull width direction. The air is blown out toward the water from the blowing portion to generate micro bubbles. Therefore, a large number of air outlets arranged in the
Only one sea chest needs to be installed, which significantly reduces the number of man-hours required to install the sea chest and the number of air supply pipes. Can be.

Further, the sea chest has a plurality of divided structures in the width direction of the hull so that at least two or more air blowing portions communicate with each divided region, and an air supply pipe is connected to each divided region. By doing so, it becomes possible to blow an arbitrary amount of pressurized air from each divided area.

[0011] Further, the air blow-out portion is constituted by an opening formed in the outer shell of the ship bottom and a perforated plate or a porous plate detachably attached to the opening, so that maintenance of the air blow-out portion can be performed. It can be done easily.

Further, by adopting a configuration in which a reinforcing doubler is attached to the peripheral portion of the opening, the strength can be easily designed even if the opening is made large.

[0013]

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

FIGS. 1A, 1B and 2A, 2B show an embodiment of an air blower of a ship with reduced frictional resistance according to the present invention. A large number of air blowing portions 3 are provided at a position between the extended longes 10 so as to be arranged in a line in the hull width direction, and all the air blowing portions 3 are covered from the inside of the bottom outer panel 1 and communicate with each other. A channel-shaped steel chest 11 extending continuously over the entire length of the hull in a water-tight manner is attached to the bottom shell 1 so as to straddle each of the longes 10, and a longitudinal center of a web 11a serving as an upper surface of the sea chest 11 is provided. Air supply port 1
The air supply port 14 is connected to the other end of an air supply pipe 13 whose one end is connected to an air supply device (not shown), and is supplied into the sea chest 11 through the air supply pipe 13. The pressurized air is dispersed in the hull width direction in the sea chest 11 so that it can be guided to each air blowing unit 3. The sea chest 11 is provided on the upper surface 10 of the longitudinal 10 so that no resistance is generated in the pressurized air passing therethrough.
a sufficient space is formed between the sea chest 11 and the worker.

The air blowing section 3 is shown in FIG.
(B) As shown in detail in (b), a ring-shaped reinforcing doubler 1 is provided on a peripheral edge on a circular opening 4 formed in the bottom shell 1 of the ship.
5, the opening 4 is doubled, and a ring-shaped support plate 17 having an opening 17 a in the center is provided at a radially inner position of the doubler 15 with a bolt 18 from the inside of the bottom shell 1. The support plate 17
And a perforated plate 16 having a number of air outlets 5 formed therein.
Are detachably attached from the outside of the bottom shell 1 by stud bolts 19 and cap nuts 20 projecting from the lower surface of the support plate 17. The above-mentioned reinforcing doubler 15 may be attached in a ring shape by welding what has been divided in advance.

In addition, T-shaped notches 12 are provided at required positions of the flanges 11b, which are front and rear side surfaces of the sea chest 11, in accordance with the cross-sectional shape and the arrangement interval of the longes 10, so that a hull can be constructed. , Cut out 12 and longe 1
The sea chest 11 can be set above the air blowing portion 3 so as to be fitted into the boat 0 from the master direction.

The pressurized air sent from the air supply device to the sea chest 11 through the air supply pipe 13 is smoothly dispersed in the hull width direction in the sea chest 11, and each air blowing portion arranged in the hull width direction. 3, the air is blown out of the ship from the air outlet 5 of the perforated plate 16 of each air blower 3, so that voids formed by the generated microbubbles can cover the ship bottom surface widely. Become like

In the above description, the sea chest 11 extends continuously in the width direction of the hull, and surrounds all of the multiple air blowing portions 3 arranged on the bottom shell 1 so as to integrally surround the air blowing portions 3. Since they are commonly used, it is not necessary to individually attach the sea chests 7 to the large number of air blowing portions 3 as shown in FIG.
Since the sea chest 11 is configured to communicate in the hull width direction, only one air supply pipe 13 connected to the sea chest 11 can be provided. Therefore,
The number of work steps for installing the sea chest 11 and the air supply pipe 13 can be greatly reduced as compared with the structure shown in FIG. 6, and the installation can be performed at low cost.

Further, in each of the air blowing portions 3, the sea chest 7 is not individually attached around the opening 4 to which the perforated plate 16 is attached as shown in FIG. Since the reinforcing doubler 15 is attached, the strength can be increased even if the opening 4 is enlarged, and the strength can be easily designed.

Further, the perforated plate 1 of each of the air blowing portions 3 is provided.
At the time of installation, 6 can be attached to the bottom outer panel 1 in an easy and downward posture using bolts 18 from the inside of the ship via the support plate 17, and after installation, the cap nut 20 is tightened and removed. Since the air outlet 5 of the perforated plate 16 becomes clogged, the work such as maintenance and replacement can be easily performed since the air outlet 5 of the perforated plate 16 can be freely attached and detached.

Next, FIGS. 3A, 3B, and 3C show other embodiments of the present invention, and FIG.
FIG. 3B shows a case where each of the air blowing portions 3 has an oval shape that is long in the front-rear direction, which is the ship length direction. FIG. Are arranged in a zigzag pattern in the width direction of the hull, and FIG.
Shows a case where the area of each circular air blowing portion 3 is gradually increased from the central portion in the hull width direction toward the width end portion.

As shown in FIG. 3A, FIG.
(A) The amount of pressurized air to be blown out can be increased as compared with the embodiment shown in (B), and as shown in FIG. 3 (B), it is advantageous in terms of hull strength, and 3 (c), the air blowing amount in the hull width direction can be made more uniform.

The present invention is not limited to the above embodiment, and the shape, area and the like of the air blowing portion 3 can be freely determined so as to obtain a desired hull covering effect by micro bubbles. Also, in the embodiment, the case where the sea chest 11 is attached to the entire length in the hull width direction has been described, but a partition is provided in the middle of the hull width direction, or the middle is divided, and a plurality of divided structures are provided. As an alternative, at least two or more air blowing portions may be communicated with each divided region, and an air supply pipe may be connected to each divided region, whereby an arbitrary amount of pressurization from each divided region may be achieved. Air can be blown out, and the air blow-out part 3 is a perforated plate 16
Alternatively, a porous plate may be used as in FIGS. 5 (a) and 5 (b), or an air outlet may be directly formed in the bottom shell 1 without departing from the spirit of the present invention. Of course, various changes can be made within the range.

[0024]

As described above, the air blower of the ship for reducing frictional resistance according to the present invention exhibits the following excellent effects. (1) A large number of air blowing portions for generating microbubbles by blowing pressurized air into water are provided on the bottom shell of the ship, arranged in the width direction of the hull, and On the inner side, a common sea chest for guiding the pressurized air supplied through the air supply pipe to each of the air blowing sections is assembled in the width direction of the hull so as to straddle the longitudinal section of the bottom of the hull. One and only one sea chest and one air supply pipe may be installed for each of the plurality of air blowout sections, and the number of work steps required for installation can be reduced, and the installation cost can be reduced. (2) The sea chest is divided into multiple parts in the hull width direction,
An arbitrary amount of pressurized air is blown from each divided region by connecting at least two or more air blowing portions in each divided region and connecting an air supply pipe to each divided region. Can be done. (3) Maintenance of the air blowing section is facilitated by forming the air blowing section with an opening formed in the outer shell of the ship bottom and a perforated plate or a porous plate detachably attached to the opening. It can be carried out. (4) By attaching a doubler to the periphery of the opening in a perforated plate or an air blower using a porous plate, the strength of the opening can be easily increased, so that strength design becomes easy.

[Brief description of the drawings]

FIG. 1 shows an embodiment of an air blower of a frictional resistance reducing ship according to the present invention, wherein (a) is a schematic perspective view, and (b).
Is a schematic plan view.

FIG. 2 is an enlarged view showing an air blowing portion of the air blowing device shown in FIGS. 1 (a) and (b), wherein (a) is a plan view,
(B) is an AA arrow view of (A).

FIG. 3 shows another embodiment of the present invention.
(B) and (c) are bottom views each showing an example of a different arrangement shape of the air blowing portion.

FIGS. 4A and 4B show an example of an air blower proposed so far, in which FIG. 4A is a cut side view and FIG. 4B is a bottom view.

FIG. 5 shows another example of the air blower proposed so far. (A) shows a case where a porous plate is used, and (B) shows an air blowout port on the outer bottom plate of the ship. It is a bottom view at the time of directly perforating.

FIG. 6 is a schematic plan view showing an example of a state in which conventional air blowers are arranged so as to be arranged in the hull width direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ship bottom outer plate 3 Air blowout part 4 Opening part 5 Air blowout opening 10 Longe 11 Sea chest 13 Air supply pipe 15 Reinforcement doubler 16 Perforated plate

Claims (4)

[Claims] 1. A large number of air blowing portions for generating fine air bubbles by blowing pressurized air into water are provided on a bottom outer plate of the ship, arranged in the width direction of the hull,
A common sea chest for guiding the pressurized air supplied through the air supply pipe to each of the air blowing portions is assembled in the hull width direction on the inner side of the hull bottom outer plate so as to straddle the longitudinal of the hull bottom. An air blower for a ship with reduced frictional resistance, comprising: 2. A sea chest having a plurality of divided structures in a hull width direction, wherein at least two or more air blowing portions are communicated in each divided region, and an air supply pipe is connected to each divided region. 2. The air blower of the ship for reducing frictional resistance according to 1. 3. The frictional resistance according to claim 1, wherein the air blowing portion comprises an opening formed in the outer shell of the ship bottom and a perforated plate or a porous plate detachably attached to the opening. Air blower for reduction ship. 4. The air blower according to claim 3, wherein a reinforcing doubler is attached to a periphery of the opening.