JP2010070155A - Casing for jet propulsion system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a casing for a jet propulsion system, capable of converting a ship to be propelled with an existing screw propulsion system into a ship to be propelled with a water jet propulsion system, and suppressing vibration by installing an impeller outside the ship. <P>SOLUTION: The casing X forming an outer shell of a water jet propulsion system A to be used for a ship S1 includes a casing body provided along a stern plate from a rear bottom part of the ship S1 with its rear end being present above the water, and includes a pipe with a water flow passing therethrough, a jet nozzle 12 for jetting the water flow formed at a rear end of the casing body 10, and an impeller storage part 11 for storing the impeller of the water jet propulsion system A provided on a fore end opening part side inside the casing body 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a casing for a water jet propulsion device used in a ship.

  A water jet propulsion device used as a ship propulsion device has an advantage that the influence of cavitation is small and the ship speed can be increased as compared with a screw propeller propulsion device. The water jet propulsion device normally has a structure in which water is taken in from a hole provided in the bottom of the ship and water is injected from a rear injection nozzle by a pump including an impeller provided in the ship.

Since the water jet propulsion device needs to form a hole in the bottom of the ship as described above, it is extremely difficult to convert a ship propelled by an existing screw propeller propulsion device into a boat propelled by a water jet propulsion device. In addition, since an impeller for generating a water flow constituting the water jet propulsion device is provided in the ship, there is a problem that vibration is easily transmitted to the ship.
In view of such a problem, the present invention makes it possible to convert a ship propelled by an existing screw propeller propulsion device into a ship propelled by a water jet propulsion device, and by installing an impeller outside the ship. An object is to be able to suppress vibration.

In order to solve the above problems, the present invention has the following configuration.
The invention according to claim 1 is a casing that forms the outer shell of a water jet propulsion unit used in a ship, and is provided along the stern plate from the rear part of the bottom of the ship so that the rear end part is on the water. A casing main body comprising a tubular body through which a water flow passes, an injection nozzle for injecting a water flow formed at a rear end portion of the casing main body, and an impeller of the water jet propulsion device provided on the front end opening side inside the casing main body Is a casing for a water jet propulsion device having an impeller accommodating portion for accommodating the impeller.
According to a second aspect of the present invention, in the casing for a water jet propulsion unit, the casing for the water jet propulsion unit is attached to a screw ship that is a ship having an existing screw propeller propulsion unit. The screw propeller of a screw ship is used.
According to a third aspect of the present invention, in the casing for a water jet propulsion unit according to the first aspect, the casing for the water jet propulsion unit is attached to a screw ship which is a ship having an existing screw propeller propulsion unit. The screw propeller of this ship is replaced with an impeller used for an axial flow pump, and this impeller is used as the impeller.
The invention according to claim 4 is a ship provided with a water jet propulsion device having the casing for water jet propulsion device according to claim 1.
The invention described in claim 5 is a ship provided with the water jet propulsion casing described in claim 2 on the screw ship.
The invention described in claim 6 is the ship provided with the water jet propulsion casing according to claim 3 in which the screw propeller is replaced with an impeller used for the axial flow pump in the screw ship.

If the casing for water jet propulsion devices according to the invention of claim 1 is used, the water jet propulsion device can be provided along the stern plate from the rear part of the bottom of the ship, so there is no need to make a hole in the hull, and existing screw propeller A ship propelled by a propulsion device can be easily remodeled into a ship propelled by a water jet propulsion device, and since the impeller exists outside the ship, vibrations in the hull are unlikely to occur.
The invention described in claim 2 can be modified to a ship propelled by a water jet propeller using the screw propeller of the ship having the screw propeller propeller as it is.
The invention according to claim 3 can be modified to a ship propelled by a water jet propulsion device using the engine and propulsion shaft of the ship having a screw propeller propulsion device as they are.
In the invention according to claim 4, since the impeller exists outside the ship, vibration can be suppressed.
The inventions described in claims 5 and 6 can be manufactured as a ship having a water jet propulsion device simply and at low cost by using an existing screw ship as it is.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a partially broken side view schematically showing the structure of a water jet propulsion device A including a water jet propulsion device casing X according to the embodiment, and FIG. 2 is a rear view of the water jet propulsion device A. The water jet propulsion device A is provided in a small ship S1 having a screw propeller propulsion device P.
The water jet propellant casing X includes a casing main body 10 formed of a bent tube body formed along the stern plate B from the rear portion of the ship bottom D, and a screw propeller of a screw propeller propulsion device P provided on the front end side of the casing main body 10. An impeller storage portion 11 for storing Ps and an injection nozzle 12 provided on the rear end side of the casing body 10 are configured. The position where the injection nozzle 12 of the casing body 10 is provided is formed on the water in a state where it is attached to the ship S1. Further, the inner diameter decreases from the impeller housing 11 toward the injection nozzle 12. Here, the opening area of the injection nozzle 12 is set to about one half of the area of the screw propeller Ps. The impeller accommodating portion 11 is formed by a short cylindrical cover that is substantially in contact with a trajectory passing through a position farthest from the rotation axis of the blade of the screw propeller Ps of the ship S1. The outer peripheral surface of the cover is formed integrally with the casing body 10 so as to seal the inside of the casing body 10.

The water jet propulsion casing X having such a configuration is obtained by removing the rudder from the existing ship S1 and attaching the rudder to the position where the rudder is provided as shown in FIGS. A screw propeller Ps that feeds water to X is built in, whereby a water jet propulsion device A is formed. When the rudder is removed, in order to change the direction, it is necessary to provide a deflector that operates to the left and right outside the injection nozzle 11, or to provide a nozzle that operates to the left and right outside the injection nozzle. In order to make this possible, it is necessary to provide a reverser, which is omitted here.
By using the water jet propulsion casing X having such a structure as described above, a ship propelled by an existing screw propeller propulsion apparatus can be remodeled to a ship propelled by a water jet propulsion apparatus relatively easily. It becomes.
Here, the small ship S1 is taken as an example. However, as shown in FIGS. 3 and 4, by using the water jet propulsion casing X2 having the same structure for the large ship S2, the existing ship S1 is used. It is possible to remodel a ship propelled by the screw propeller propulsion device into a boat propelled by the water jet propulsion device A2 relatively easily. In the case of a large ship, it is desirable to replace the impeller Ip used for the axial flow pump instead of the screw propeller. In this case, the impeller storage portion 15 needs to have a size that matches the size of the replaced impeller Ip. Moreover, what consists of several opening is employ | adopted as the injection nozzle 14 of the casing X2 for water jet propulsion devices. This is to suppress the reduction of the propulsive force by facilitating taking air into the jetted water flow. Here, the size of the impeller Ip is about 70% of the diameter of the original screw propeller, and the total opening area of the injection port is about 50% of the area of the impeller Ip.

  In the above embodiment, it has been shown that a ship propelled by an existing screw propeller propeller is modified. However, in a new ship, a ship having the above-described structure is made using the casing for a water jet propeller according to the present application. It is also possible. Even in a small boat, the impeller may be appropriately changed to an impeller used for an axial flow pump instead of a screw propeller.

It is a partially broken side view schematically showing the structure of a water jet propulsion unit including a water jet propulsion casing according to an embodiment. It is a rear view of the water jet propeller according to the embodiment. It is a partially broken side view showing typically the structure of the water jet propulsion unit including the casing for the water jet propulsion unit used in the large ship according to the embodiment. It is a rear view of a water jet propulsion device used for a large ship according to an embodiment.

Explanation of symbols

X, X2 Water jet thruster casing A, A2 Water jet thruster S1, S2 Ship Ps Screw propeller Ip Axial pump impeller 10 Casing body 11, 15 Impeller storage 12, 12, Injection nozzle

Claims (6)

A casing that forms the outer shell of a water jet propulsion unit used in a ship,
A casing body made of a tubular body through which a water flow passes, provided along the stern plate from the rear bottom of the ship so that the rear end portion is on the water;
An injection nozzle for injecting a water flow formed at the rear end of the casing body;
A casing for a water jet propulsion device, comprising: an impeller accommodating portion for accommodating an impeller of the water jet propulsion device provided on a tip opening side in the casing main body. The water jet propulsion casing is attached to a screw ship that is a ship having an existing screw propeller propulsion unit,
The water impeller casing according to claim 1, wherein the impeller is a screw propeller of the screw ship. The water jet propulsion casing is attached to a screw ship that is a ship having an existing screw propeller propulsion unit,
The water jet propulsion casing according to claim 1, wherein the screw propeller of the ship is replaced with an impeller used for an axial flow pump, and the impeller is used as the impeller.   A ship provided with a water jet propeller having the water jet propeller casing according to claim 1.   A ship provided with the water jet propulsion casing according to claim 2 on the screw ship.   The ship provided with the casing for a water jet propulsion device according to claim 3 by replacing the screw propeller of the screw ship with an impeller used for the axial flow pump.

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