JP2898556B2 - Ship intake system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water intake device for a ship,
For example, it is advantageously used for a water jet propulsion ship.

[0002]

2. Description of the Related Art A ship is provided with a water intake device for taking water from a hull for various purposes. And, in order to protect the intake pump and prevent the blockage of the flow path,
A device for preventing foreign matter such as dust from entering is provided. For example, in the water jet propulsion boat, conventional, as shown in FIG. 4, a grid 10 which is fixed to the ship bottom 1 to the position of the intake port 3
Is provided.

[0003] However, since this grid is firmly assembled in a grid shape to withstand the resistance of water passing at high speed and the impact force caused by the collision of foreign matter, the water flow is disturbed in the grid portion and a large pressure is generated. Loss is generated and the propulsion efficiency of the water jet propulsion vessel is reduced. In addition, if a flat floating material such as a vinyl sheet is covered on the grid by the suction force of the pump, it will not be peeled off, and the intake will be blocked and water intake will not be possible, causing serious problems such as stopping the water jet propulsion. generate. Furthermore, since foreign matter collides with the grid at a high flow rate, the foreign matter is interposed between the grids to further disturb the water flow, and also causes a problem that the water is strongly locked and cannot be easily removed.

[0004] In order to solve such a problem, there has been proposed a water intake device provided with a fin below the water intake port (Japanese Patent Laid-Open No. 4-2).
43687). However, even if the fins are provided in this way, if a vinyl sheet or the like flows into the water intake portion, as in the case of the grid, the fins are not separated from the fins due to the suction force of the pump, which is important for water jet propulsion. Affect. In addition, since these fins are under the intake, a separate support structure must be provided from the hull in the middle of the intake to support the fins, which complicates the structure of the intake and reduces extra resistance. Occur. Furthermore,
Since the fins are located below the water intake, when foreign matter is clogged between the fins, the flow path is directly closed to make the flow path narrower, and the turbulence and resistance of the flow are greatly increased. That is, such a fin does not sufficiently solve the problem in the grid. Furthermore, since the fins are attached across the water intake in the streamline direction, their lengths become unnecessarily long, not only using extra materials but also increasing the viscous resistance. In addition to lowering the propulsion performance, the lateral load applied during rolling of the ship increases, and it is difficult to obtain a structurally safe supporting strength.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the prior art, and has a small pressure loss in the water intake system, a simple structure of the opening, easy manufacture, and foreign matter clogging in the opening. It is another object of the present invention to provide a water intake device for a ship that can prevent foreign substances from entering an opening.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a water intake device for a ship , comprising: an opening provided in a bottom of a hull; a substantially streamline direction from the ship bottom <br/> a predetermined protrusion height to standing plate member streamline direction upstream side portion on the upstream side of the flow line of the water during forward crotches and the plate-like member which is inclined to the downstream side of the flow line direction from part toward the tip, a flow path communicating to the one end of the opening provided in the interior of the hull, provided the flow path Water supply means for sucking water from the opening.

[0007]

According to the first aspect of the present invention, an opening is provided at the bottom of the hull, a flow path is provided with this opening as one end side, and a water supply means for sucking water from the opening is provided therein. Therefore, when the water supply means is operated, water is sucked from the opening. In this case, the boat speed, the shape of the opening, depending on the conditions such as the water supply rate, flow lines of the water is sucked into the opening in the portion close to the ship bottom is formed. Of this flow line, following those farthest from the ship bottom of "critical flow line".

On the other hand, on the upstream side of the flow line during forward a vicinity of the opening is protruded a predetermined height from the ship bottom and upright plate member. The upstream side of the plate member in the streamline direction is inclined toward the downstream side in the streamline direction from the base to the tip. As a result, for example, if the predetermined height is near the critical streamline at a predetermined ship speed, foreign matter such as dust is
Even when flowing in this streamline and approaching the opening, if it hits the plate-like member, it is transported along the slope to the tip of the plate-like member,
When it leaves the tip, it goes out of the critical streamline, so it is not sucked into the opening.

In this case, since the foreign matter has a velocity in the direction along the slope, the foreign matter is likely to be blown from the tip of the plate-like member and come out of the critical streamline. In addition, since the inertia force is large when the foreign matter is large, even if the foreign matter does not come out of the marginal streamline when leaving the plate-like member, it does not follow the curvature when the marginal streamline bends and goes out of the marginal streamline. May not be sucked into the opening. Therefore, the predetermined height does not necessarily have to be higher than the position of the critical streamline. In such a case, for example, a sheet that is easily adsorbed to the opening, such as a vinyl sheet, may flow into the flow path from the opening, but since there is no need to provide a grid at the opening, in water jet propulsion The water is conveyed together with the water by the water supply means and discharged outside without causing any trouble. Therefore, in a water jet ship, for example, the ship speed when the ship reaches a certain ship speed after departure and foreign matter is easily entrained is set to a predetermined ship speed, and a predetermined height is set near the critical streamline at this time. This will ensure safe navigation for the intake system. Such a predetermined height is generally determined by the type of ship, the operating area of the ship, the operating speed,
It is appropriately determined in the actual ship design depending on the type of foreign matter generated.

This plate-like member is literally a flat member,
The resistance is small because it is set up almost in the streamline direction. Note that the resistance can be further reduced by rounding the tip of the plate-like member or forming it in a streamlined manner like a fin. Further, since this plate-shaped member is provided on the upstream side of the opening, it comes into contact with the hull over the entire length in the streamline direction, so that it is easy to provide strong and stable support. In addition, the opening does not require any support structure. Therefore, the structure of the opening is simplified, the manufacture of the entire water intake device is facilitated, and unnecessary resistors are not required. In this respect, the propulsion performance is improved. Furthermore, since the plate-shaped member only needs to have a function of causing a foreign object to jump out of the streamline when hit, the length is not originally a necessary condition. Therefore, a long dimension that covers the opening is not required at all. As a result, material costs are reduced and frictional resistance is reduced. In addition, such a plate-like member has an anti-rolling effect on rolling and the like of a ship and a course stabilizing effect as an aid of rudder. Due to the effect, even if it receives an external force, it can withstand this sufficiently.

According to the second aspect of the present invention, when a plurality of plate-like members are provided, the respective plate-like members are alternately arranged so as to be displaced in the streamline direction. Is almost eliminated.

[0012]

FIG. 1 shows the overall structure of a water jet propulsion ship water intake device as an example of a water intake device for a ship. The water intake device includes an intake port 3 as an opening provided on the bottom 1 of the hull , and an upstream portion of a water stream line 4 in the vicinity of the water flow when the ship advances in the direction of arrow A in a substantially streamline direction. fin 5 as a predetermined height h only plate member which is erected to protrude from the hull 1, the intake duct 6 as a flow path communicating with the intake port 3 provided in the interior of the ship bottom 1, provided in this And a pump 7 serving as a water jet propulsion device as a water supply means for sucking water from the water intake port 3.

The water intake 3 is below the water surface 2. Among the ship bottom near the water, streamlines of water close to the ship bottom 1 than the limit streamline 4a is sucked into the intake 3. This streamlines, somewhat varies with the pump flow rate and the then determined boat speed, but from <br/> ship bottom 1 limit flow line 4a when the ship reaches to some extent or more boat speed after departure When the distance is H, the height h of the fin 5 is H
It is desirable that it is equal to or higher than that.

In this embodiment, three fins 5 are provided.
The fins 5 are arranged alternately in the streamline direction. With this arrangement, foreign matter is hardly caught between the fins 5. In addition, the anti-oscillation effect by the fins increases. However, depending on the type and size of foreign matter such as dust in the sea area where the ship travels, three fins 5 may be arranged side by side as shown by a two-dot chain line in the figure. In this case, the exclusion of foreign matter is improved. In the case where the fins 5 are all arranged side by side as described above, even if foreign matter is caught between the fins, the water intake port itself is not covered, so that water can be taken in the water intake port 3 from another streamline, and the foreign matter is caught in the grid. There is no significant effect as in the case of In addition, the number of fins 5, the interval, and the like are appropriately determined according to various conditions.

In the intake duct 6, a pump shaft 7a, which is connected to a diesel engine or the like (not shown) and driven to rotate, is provided through the duct. The rear end of the intake duct 6 protrudes from the transom 1a of the hull, and has a reduced cross section so as to jet a water jet at a high speed.

FIG. 2 shows an example of the shape of the fin 5. The fin 5 has an inclined surface 5a as an upstream portion in the streamline 4 direction inclined from the base 5b toward the tip 5c toward the downstream side in the streamline direction. In the present embodiment, the inclined surface 5a is sharpened, and the upper end 5d and the rear end 5e are rounded to reduce the resistance. Fins 5 is fixed by welding or the like on the ship bottom 1 over its entire length. Therefore, the fins 5 have sufficient mounting strength against external force, and can sufficiently withstand the external force moment when exhibiting the swinging effect and the needle keeping effect.

FIG. 3 shows the behavior when foreign matter flowing in the critical streamline 4a from the upstream side hits the fin 5. When a foreign matter W such as a piece of wood flows at a high speed and collides with the fin 5, an inertial force F and a drag D due to the flow act on the foreign matter W, and a reaction force R acts from the slope 5a based on the inertia force F and the drag. W moves in the direction along the slope. However, since the center of gravity of the foreign matter does not necessarily hit the slope, the foreign matter tends to rotate and move off the slope. As a result, the foreign matter follows various courses depending on the place where the foreign matter hits the slope, but as shown in the figure, the foreign matter is transported to the slope by a certain distance and then leaves the slope.
After that, since the inertial force in the inclination direction remains, the foreign matter moves slightly outward and flows again along the streamline. The foreign matter W 'that has collided with the portion near the tip of the fin 5 is reliably transported to the outside of the tip 5d of the fin 5, and is blown out of the limit streamline 4a.

In the water jet propulsion device, a foreign substance such as a piece of wood having a long length is clogged in the intake duct 6 between its inner walls or between the inner wall and the pump shaft 7a, or a large impact force is applied to the pump 7. Giving and damaging this is most problematic. However, when such a long foreign matter flows at a high flow velocity and collides with the fin 5, the foreign matter is often carried to the tip of the slope 5a by the upstream fin.
Depending on the contact point, the fin is carried to the tip by the next fin on the downstream side. Further, when the fins 5 are arranged side by side, the fins 5 are often transported to the leading end over two fins.

When a foreign substance comes away from the fins 5 and reaches the water intake 3, if the foreign matter is conveyed or blown to the outside of the critical streamline 4 a by the fins 5, the foreign matter is naturally not sucked into the water intake 3. The same applies to soft foreign substances such as vinyl. On the other hand, since the streamline is curved above the water intake 3, the inertia force becomes relatively large when the foreign matter is large. It will not be sucked along the intake.

The above-described various behaviors of the foreign matter include the size, weight, shape, etc. of the foreign matter that need to be prevented from flowing into the intake port when a constant ship speed and pump flow rate are given, and the fins. It is determined in relation to the number of sheets, interval, height, inclination angle, length, etc., which are the design specifications of No. 5. Therefore, the fin 5 is determined to have an optimum shape, size, and the like for each specific ship to which the present invention is applied in consideration of such points.

Although the above description has been given of the case where the water intake device for a ship according to the present invention is mounted on a water jet propulsion ship, the present invention is not limited to this. Of course, the present invention can be applied to other water intake devices.

[0022]

As described above, according to the present invention, in accordance with the first aspect of the present invention, the provision of the plate-like member on the upstream side of the opening prevents entry of foreign matter into the opening. According to this water intake device, the pressure loss of the water intake system is reduced, the structure of the opening is simplified, the production becomes easy, there is no obstruction of foreign matter in the opening, and the plate-like member has sufficient support. It is supported stably in terms of surface. In addition, a lowering effect and a needle keeping effect can be obtained. In the invention of claim 2, in addition to the above, by alternately arranging the plate-like members, it is possible to prevent the foreign matter from being blocked between the plate-like members.

[Brief description of the drawings]

FIG. 1 shows an overall configuration of a water intake device of a ship according to an embodiment;
(A) is a sectional view, and (b) is a plan view.

FIGS. 2A and 2B show the shape of a fin of the above-described device, wherein FIG. 2A is a side view, FIG. 2B is a front view, and FIG. 2C is a cross-sectional view taken along line cc of FIG.

FIG. 3 is an explanatory diagram showing a behavior when a foreign object hits a fin.

FIG. 4 shows the structure of a grid portion of a conventional intake,
(A) is a side view and (b) is a plan view.

[Explanation of symbols]

1 the ship bottom 2 Water 3 intake (opening) 4 streamlines 5 fins (plate member) 6 intake duct (channel) 7 pump (water supply means)

Continuation of the front page (56) References JP-A-4-243687 (JP, A) JP-A 62-94999 (JP, U) JP-B 46-16693 (JP, B2) (58) Fields investigated (Int) .Cl. ⁶ , DB name) B63H 11/01

Claims (1)

(57) [Claims] 1. A and an opening provided in the ship bottom of the hull, and protrudes a predetermined height from the ship bottom substantially streamline direction upstream of the water during forward a vicinity of the opening portion streamlines standing and the plate-like member comprising a plate-shaped member that is set is the upstream portion of the flow line direction is inclined to the downstream side of the stream line toward the tip end from the base portion, the opening provided inside the hull To one end
Intake device of the ship, characterized in that it comprises a flow passage communicating with this, and water means for sucking the water from the opening provided in the flow path, the Te.