JPH09286394A - Jet water suction in water jet propulsion ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make effective use of high speed performance without leaving resistance-causing parts in a ship's bottom area by disposing a screen grid over a suction inlet located in a forward facing area of the ship's bottom and disposing a hood smoothly connected to a suction water flow passage. SOLUTION: A casing 2 has at its rear end a jet water spout nozzle 2a opening rearward and at its front end a suction opening 2b facing forward at a ship's bottom surface 1a of a ship's body 1. The suction opening 2b is formed in an elliptic shape with its major axis in the traveling direction of the ship. A suction opening 5c disposed in front of the suction opening 2b at the ship's bottom surface 1a is covered with a screen grid comprising a fixed screen grid and a movable screen grid 5f for preventing foreign objects from being suctioned. A hood 5 is disposed over a suction water flow passage formed in the ship's body 1 for smooth connection between the opening 5c and the opening 2b. This eliminates resistance-causing parts in the ship's bottom area 1a so that high speed performance is effectively utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a water jet water suction device in a water jet propulsion ship, which smoothly sucks the jet water and exhibits a highly efficient propulsive force without causing a running resistance. It is intended to provide a device capable of doing so.

[0002]

2. Description of the Related Art Conventionally, it has been well known to provide a scoop or a hood at the jet water suction port in this type of water jet propulsion ship. JP 7
-101392 is an example in which a scoop is provided, and JP-A-5-294283 is an example in which a hood is provided. Also,
In addition to these, there is also known one that adjusts the opening degree of the suction port, and JP-A-5-270486 is an example thereof.

[0003]

However, in the prior art as described above, not only the structure is complicated because the suction opening is provided with means for adjusting its opening degree and flow. These may project downward from the bottom of the ship, hindering navigation, and dust may be caught. Also,
Even if a hood is provided, the hood and the suction port may not be smoothly connected, dust or the like may be caught at the connection portion, or a low pressure portion may be generated to cause cavitation.

[0004]

SUMMARY OF THE INVENTION The present invention is capable of overcoming the above-mentioned conventional drawbacks, and the gist of the present invention is to provide a jet water which is opened at the bottom of a water jet propulsion ship. The suction port is formed in an elliptical shape having a major axis in the sailing direction of the hull, and a screen grid is provided at the water intake port provided on the front surface of the hull, and the flow path of the suction water is provided in the hull. It has a hood that can be smoothly connected to.

The screen grid provided on the hood may be a fixed one or a combination of a fixed one and a movable one. Further, it is preferable to provide a slit along the flow direction of the suction water in the abdomen of the hood, since dust and the like are unlikely to adhere to the slit.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the device according to the present invention, since the jet water suction port has an oval shape along the traveling direction of the hull,
It can smoothly absorb water without going against the flow of suction water, and has a wide suction port, so that a large amount of water sucked into the hood can be absorbed.
It can be efficiently used as dynamic pressure. In addition, by providing a screen grid on the front of the hood, the suction port will not be blocked, and since the inner surface of the hood is smoothly connected to the inner surface of the casing, the suction water is guided smoothly to the impeller. However, it is possible to prevent cavitation.

Further, if the screen grid provided on the hood is constructed by combining a fixed type and a movable type, it is possible to easily remove dust and the like if they adhere, and
If a slit groove is formed in the abdomen of the hood along the traveling direction, it can be operated as an auxiliary water intake port. Hereinafter, the present invention will be specifically described with reference to the drawings.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 is a hull, 2 is a casing forming a flow path of a water jet, 3 is an impeller provided in the casing 2, and 4 is a driving machine of the impeller 3.

A jet water jet nozzle 2a is provided at the rear end of the casing 2, and the front end of the casing 2 is
A suction port 2b is opened on the bottom surface 1a of the hull 1. The suction port 2b is formed in a rectangular shape having a major axis in the sailing direction of the hull 1. The suction port 2b is provided with a through hole 5a matching the suction port as shown in FIG. Is installed.

Next, the structure of the hood 5 will be described. The hood 5 is attached to the abdomen of the hull by a mounting surface 5b so as to cover the suction port, and a water inlet 5c is formed in the front part (based on the traveling direction of the hull) of the abdomen. A slit 5g is formed in the vehicle along the traveling direction of the hull 1. Further, a screen grid for dust removal consisting of a fixed screen grid 5e and a movable screen grid 5f is attached to the water inlet 5c.

In the figure, reference numeral 5g is a slit provided on the abdominal surface of the hood 5 and provided in the running direction of the hull 1, and reference numeral 5d is a skid prevention plate provided on the abdominal surface of the hood 5. Further, in FIG. 1, reference numeral 2c is an injection adjusting plate.

The apparatus according to the present invention is configured as described above, and the water absorbed from the water inlet 5c smoothly flows through the flow passage in the hood 5 and the flow passage in the casing 2 and is sucked into the impeller 3. And is ejected from the nozzle 2a to propel the hull 1.

In sucking and jetting this jet water,
In this invention, since the suction port 2b of the casing 2 is formed in an oval shape, a water flow flowing under the hull 1 can be sufficiently taken in, and the water flow can be taken in smoothly so that the power water flow can be efficiently supplied. Can be supplied to the impeller 3.

That is, since the suction water is sufficiently supplied to the front part of the impeller 3, the pressure of the part does not become low, so that cavitation does not occur and the water is jetted from the nozzle 2a as the water jet with the highest suction efficiency. can do.

The hood 5 provided at the suction port 2b can maximize the power flow flowing through the bottom of the ship and guide it to the suction port 2b. In particular, it projects to the bottom of the ship like a conventional scoop or hood. Since it does not exist, it does not become a resistance against the sailing of the hull, and there is no possibility that dust or the like will be caught on the hood 5.

The screen grid provided at the water inlet 5c on the front of the hood 5 can prevent dust from being sucked into the hood 5, and the screen grid is of a fixed type as shown in FIG. By using a structure that combines a movable type and a movable type, it is possible to easily remove the vinyl film etc. that is difficult to remove that is caught on this water flow WS under the hull.
Can be removed by flushing backwards. (See Fig. 1)

Further, the slit 5g opened on the lower surface of the hood 5 automatically adjusts the amount of water in the hood 5 to make the impeller 3
Can be activated. That is, when there is little jet water, such as when running at low speed, this slit 5
When a large amount of jet water is required to escape from the hood out of the hood from the g, such as when traveling at high speed, the outside water can be absorbed from the slit 5g and supplied to the impeller 3.

[0018]

As described above, the device according to the present invention is provided in the high-speed watercraft using a water jet so that the water intake port on the lower surface of the hull is substantially aligned with the bottom of the ship as compared with the conventional device. While sailing, there is no resistance on the bottom of the ship and high speed performance can be demonstrated.
Especially, since the inner surface of the hood provided at the bottom of the ship and the water passage for suction water to the impeller are smoothly connected, it is possible to supply cavitation to the impeller without loss of dynamic pressure of the suction water. Instead, the hull can be propelled with maximum efficiency.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional side view of a propulsion unit of a water jet propulsion ship according to the present invention.

FIG. 2 is likewise a front view taken along the arrow A in FIG.

3 is a bottom view of the same as seen along the arrow B in FIG. 1. FIG.

[Explanation of symbols]

 1 Hull 2b Suction Port 5 Hood 5c Water Suction Port 5e Fixed Grid 5f Movable Grid 5g Slit

Claims (3)

[Claims] 1. In a water jet propulsion ship, a jet water suction port 2b opened at the bottom of the ship is formed into an elliptical shape having a major axis in the traveling direction of the hull 1, and at the ship bottom around the suction port 2b. Is a water jet propulsion system in which a screen grid is provided at a water intake port 5c provided on the front surface thereof, and a hood 5 is provided so that the flow path of the suction water is smoothly connected to the suction flow path provided in the hull 1 described above. Jet water suction device on a ship. 2. The jet water suction device for a water jet propulsion ship according to claim 1, wherein the screen grid provided on the hood 5 comprises a fixed grid 5e and a movable grid 5f. 3. A jet water suction apparatus for a water jet propulsion ship according to claim 1, wherein a slit 5g is provided on the bottom of the hood 5 along the traveling direction of the hull 1.