JPH1035481A - Air cushion ship with means for adjusting internal pressure in stern seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent increase of resistance caused by the interference of waves generated in an air cushion chamber under the low speed condition with a stern seal by reducing pneumatic pressure in the air bag-like stern seal lower than pneumatic pressure in planned speed during sailing with ship speed lower than the planned speed. SOLUTION: High pressure air sent through a duct 7 out of a feed fan 4 driven by an engine is supplied from a new charge port 6 to an engine cushion chamber 3. Also, the high pressure air is supplied from the same feed fan 4 through a duct 7a to an air bag-like stern seal 2a. A movable damper 9a as a means to adjust the internal pressure in the stern seal is provided on the way of the duct 7a. In the low speed sailing, a controller 13 controls a movable damper 9a through an operating mechanism 14 on the basis of a detecting signal from a ship speed sensor 12 to adjust the internal pressure in the stern seal 2a to a value lower than a predetermined value balancing with planned speed, preferably adjust temporarily the internal pressure lower than that in the air cushion chamber 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air cushion ship capable of navigating with low resistance by lifting the hull by the air pressure of an air cushion chamber formed at the lower part of the hull, and more particularly to reducing the air pressure of an airbag-shaped stern seal. It is designed to be adjustable.

[0002]

2. Description of the Related Art As an air cushion ship that sails at high speed on the sea, a side wall type ship as shown in FIG. 5 is generally adopted, and both sides 1, 1 and a flexible stern seal 2a are provided.
And air cushion chamber 3 surrounded by bow seal 2b
Are formed below the wet deck 5, and high-pressure air is supplied to the air cushion chamber 3 through the air supply port 6.

[0003] That is, as shown in FIG.
Is supplied to the air cushion chamber 3 through the duct 7 and the air supply port 6 from the air supply fan 4 which operates in the above-described manner, and the high-pressure air sent out from the air supply fan 4 is supplied into the air bag-like form through the duct 7a and the air supply port 6a. It is also supplied to the stern seal 2a.

[0004] Air having a pressure higher than the air pressure of the air cushion chamber 3 is stored inside the stern seal 2a, and the pressure difference keeps the stern seal 2a in a predetermined shape. The difference is maintained by appropriately setting the flow resistance of the ducts 7 and 7a that guide the high-pressure air from the air supply fan 4.

[0005]

The resistance characteristics of the conventional air cushion ship in plain water as described above were determined by a model test, and the results shown in FIG. 7 were obtained. As is apparent from the graph of FIG. 7, there is a portion 8 where the resistance transiently increases at a relatively low ship speed, and as a result of investigating the cause, the following has been clarified. That is, as shown in FIG. 8, the water surface 15 in the air cushion chamber 3 during the cruising does not generate waves at the planned speed, and the stern is formed by the air pressure inside the stern seal 2a suitable for the water surface 15. Although the shape of the seal 2a is set, in a low-speed state before reaching the planned speed, a wave 15a as shown by a broken line is formed on the water surface in the air cushion chamber 3.
And interfered with the lower end of the stern seal 2a, thereby temporarily increasing the resistance.

Accordingly, the present invention, based on the above findings, prevents an increase in resistance due to interference between a wave generated in the air cushion chamber and a stern seal in a low speed state after starting cruising and before reaching a planned speed. An object of the present invention is to provide an air cushion ship with stern seal internal pressure adjusting means that can be made.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an air cushion ship with stern seal internal pressure adjusting means of the present invention comprises a stern seal, a flexible stern seal and a bow seal at the lower part of the hull. In an air cushion ship having an enclosed air cushion chamber, the stern seal is formed in the shape of an airbag, and waves generated on the water surface in the air cushion chamber when sailing at a boat speed lower than a planned speed are generated by the airbag. In order to suppress interference with the lower end of the stern seal, a stern seal internal pressure adjusting means is provided for reducing the air pressure inside the stern seal at a low ship speed from the air pressure at the planned speed. And

In the above-described air cushion ship of the present invention, the state in which the air pressure in the stern seal is lower than the air pressure at the planned speed by the stern seal internal pressure adjusting means when the ship is sailing at a speed lower than the planned speed. The stern seal reduces the inflation as an airbag, and the high-pressure air in the air cushion room pushes up the stern seal and flows backward, causing waves during low-speed cruising on the water surface in the air cushion room. In addition, the lower end of the stern seal can be prevented from interfering with the waves, thereby solving the conventional problem that caused the resistance to increase transiently at low ship speeds.

The stern seal internal pressure adjusting means includes:
When configured as a movable damper provided in the middle of the duct from the air supply fan to the stern seal, the amount of air supplied into the stern seal is accurately adjusted by the movable damper,
As a result, the internal pressure of the stern seal is appropriately reduced during low-speed navigation.

Further, the stern seal internal pressure adjusting means may be configured as an adjustable inlet guide vane of an air supply fan for supplying air to the stern seal. In this case, the internal pressure of the stern seal is also adjusted accurately. During low speed navigation, the internal pressure of the stern seal is reduced so that the lower end of the stern seal does not interfere with waves on the water surface in the air cushion chamber.

Further, the stern seal internal pressure adjusting means includes:
When configured as an output adjusting means of an engine for driving an air supply fan for supplying air to the stern seal, the internal pressure of the stern seal is accurately reduced during low-speed cruising, so that the lower end of the stern seal and the air cushion chamber are provided. Interference with other waves is prevented.

If a control device is provided for controlling the stern seal internal pressure adjusting means in accordance with the detection signal from the hull speed sensor, the adjustment for reducing the stern seal internal pressure during low speed navigation is automatically performed. As a result, the interference between the lower end of the stern seal and the waves in the air cushion chamber is appropriately prevented.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an essential part of an air cushion ship with stern seal internal pressure adjusting means according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing an essential part of an air cushion ship with stern seal internal pressure adjusting means according to a second embodiment of the present invention, and FIG. 3 is an air with stern seal internal pressure adjusting means as a third embodiment of the present invention. FIG. 4 is a longitudinal sectional view showing a main part of a cushion ship, and FIG. 4 is a longitudinal sectional view showing a main part of an air cushion ship with stern seal internal pressure adjusting means as a fourth embodiment of the present invention.

First, an air cushion ship with stern seal internal pressure adjusting means as a first embodiment of the present invention will be described. In the case of this embodiment as well, like the general air cushion ship shown in FIG. An air cushion chamber 3 surrounded by the parts 1, 1 and the flexible stern seal 2a and the bow seal 2b is formed below the wet deck 5, and high-pressure air is supplied to the air cushion chamber 3 through an air supply port 6. Is supplied.

That is, as shown in FIG.
The high-pressure air sent out from the air supply fan 4 driven by the air through the duct 7 is supplied from the air supply port 6 to the air cushion chamber 3. High-pressure air is also supplied from the same air supply fan 4 to the stern seal 2a in the form of an airbag through the duct 7a.

By appropriately setting the flow resistance of each duct 7, 7a, the internal pressure of the stern seal 2a is made higher than the internal pressure of the air cushion chamber 3, thereby maintaining the shape of the stern seal 2a. It is designed to drip.

In the present embodiment, especially when the air cushion ship sails at a speed lower than the planned speed, a wave generated on the water surface inside the air cushion chamber 3 (see a broken line 15 in FIG. 8).
In order to prevent the lower end of the stern seal 2a from interfering, that is, to cause a local increase 8 in the resistance shown in FIG. 7, the air pressure inside the stern seal 2a is reduced at a low ship speed as shown in FIG. A movable damper 9a is provided in the middle of the duct 7a as a means for adjusting the stern seal internal pressure which sometimes lowers the air pressure at the planned speed. In the present embodiment, a movable damper 9 is also provided in the middle of the duct leading to the air cushion chamber 3.

Further, in this embodiment, there is provided a control device 13 for controlling the operation mechanism 14 of the movable damper 9a based on the detection signal from the boat speed sensor 12 to temporarily reduce the internal pressure of the stern seal 2a.

As is clear from FIG. 10 showing the results of the model test, the underwater resistance characteristics (solid line graph) when the air pressure of the stern seal is a predetermined value corresponding to the planned speed, and the air pressure of the stern seal in the air cushion chamber are shown. In view of the underwater resistance characteristics when the pressure is lower than the pressure (broken line graph), it is more advantageous to have the resistance characteristics as indicated by the broken line graph in the region where the boat speed is ab. Therefore, the control device 13 controls the movable damper 9a via the operating mechanism 14 in the region where the boat speed is ab in accordance with the detection signal from the boat speed sensor 12, and matches the internal pressure of the stern seal 2a with the planned speed. The pressure is adjusted to be lower than a predetermined value, and preferably, the pressure is temporarily lowered to be lower than the internal pressure of the air cushion chamber 3.

As described above, in the air cushion ship with the stern seal internal pressure adjusting means of the present embodiment, the air pressure in the stern seal 2a is reduced by the air pressure in the stern seal internal pressure adjusting means when traveling at a ship speed lower than the planned speed. Movable damper 9a as
Is adjusted to a state lower than the air pressure at the time of the planned speed, so that the stern seal 2a inflates as an airbag,
As shown in FIG. 9, the state shown by the dotted line is reduced to the state shown by the solid line, and the high-pressure air in the air cushion chamber 3 pushes up the stern seal 2a and flows backward. Even when the time wave occurs, the interference between the wave and the lower end of the stern seal 2a is avoided, thereby solving the conventional problem that caused the resistance to increase transiently at a low ship speed. .

When the stern seal internal pressure adjusting means is configured as a movable damper 9a provided in the middle of a duct 7a from the air supply fan 10 to the stern seal 2a as in the present embodiment, the movable damper 9a The amount of air supplied into the stern seal 2a is accurately adjusted, so that the internal pressure of the stern seal 2a is appropriately reduced during low-speed navigation.

Next, in a second embodiment of the present invention, as shown in FIG. 2, in an air cushion ship having an air cushion chamber 3 formed in the lower part of the hull similarly to the first embodiment, an air bag-shaped stern seal is provided. The internal pressure adjusting means of 2a is an engine
It is configured as an adjustable inlet guide vane 11a of an air supply fan 4a driven by 10.

In the present embodiment, air is supplied from another air supply fan 4 driven by the engine 10 to the air cushion chamber 3 through the duct 7 and the air supply port 6. Also, an adjustable inlet guide vane 11a is provided.

With the above-described structure, also in the second embodiment, when the ship is running at a ship speed lower than the planned speed, the adjustable inlet guide vane 11a of the air supply fan 4a for the stern seal is throttled to reduce the stern. An operation of lowering the internal pressure of the seal 2a is performed, whereby the lower end of the stern seal 2a can be prevented from interfering with waves on the water surface in the air cushion chamber 3. Therefore, the ship speeds a to b shown in FIG.
In the range (low speed state), the characteristics of the dashed line graph can be provided, and a local increase in resistance can be avoided.

In a third embodiment of the present invention shown in FIG. 3, an airbag-shaped stern seal 2 is provided as in the above-described second embodiment.
As means for adjusting the internal pressure of a, an adjustable inlet guide vane 11a of the air supply fan 4a driven by the engine 10 is provided. In addition, in order to automate the operation, the adjustable guide guide vane 11a is adjusted according to a detection signal from the boat speed sensor 12. A control device 13 for controlling an operation mechanism 14 of the type inlet guide vane 11a is provided. In this manner, in the third embodiment, the internal pressure of the stern seal 2a is temporarily reduced at a boat speed lower than the planned speed, and a local increase in resistance characteristics (see reference numeral 8 in FIG. 10). Is automatically performed.

Next, in a fourth embodiment of the present invention shown in FIG. 4, in an air cushion ship having an air cushion chamber 3 formed in the lower part of the hull similarly to the second embodiment described above, an air bag-shaped stern seal 2a is provided. The output of the driving engine 10a of the air supply fan 4a that supplies high-pressure air through the air duct 7a is adjusted, whereby the internal pressure of the stern seal 2a is adjusted.

That is, as the stern seal internal pressure adjusting means, an output adjusting means of the driving engine 10a of the air supply fan 4a is provided. In the present embodiment, in order to adjust the relationship between the pressure of the air cushion chamber 3 and the internal pressure of the stern seal 2a, the air supply fan 4 that sends high-pressure air to the air cushion chamber 3 and the engine 10 for driving the air supply chamber are used. The stern seal system is provided separately.

Also in the case of the fourth embodiment, when it is desired to reduce the internal pressure of the stern seal 2a during low speed traveling, the output of the stern seal fan drive engine 10a is reduced, and the stern seal 2a When it is desired to increase the internal pressure, the fan drive engine 10a is operated in a designed state.

Also in the case of the fourth embodiment, it is possible to automate the operation control of the fan driving engine 10a, and it is possible to control the fan driving engine 10a via a control device according to a detection signal from a boat speed sensor. As a result, the internal pressure of the stern seal 2a is reduced during low-speed navigation, so that interference between the lower end of the seal and the wave in the air cushion chamber 3 is appropriately prevented.

[0030]

As described above, according to the air cushion ship with the stern seal internal pressure adjusting means of the present invention, the following effects can be obtained. (1) When sailing at a ship speed lower than the planned speed, the air pressure in the stern seal is adjusted to be lower than the air pressure at the planned speed by Since the inflation as a bag is reduced, and the high-pressure air in the air cushion room pushes up the stern seal and flows backward, even if a low-speed cruising wave occurs on the water surface in the air cushion room, the lower end of the stern seal has a wave. This alleviates the conventional problem that has caused a transient increase in resistance at low ship speeds. (2) When the stern seal internal pressure adjusting means is configured as a movable damper provided in the middle of the duct from the air supply fan to the stern seal, the movable damper can accurately supply air into the stern seal. It is adjusted so that the internal pressure of the stern seal is appropriately reduced at low speeds. (3) The stern seal internal pressure adjusting means may be configured as an adjustable inlet guide vane of an air supply fan for supplying air to the stern seal, and also in this case, the internal pressure of the stern seal is accurately adjusted, and Sometimes the internal pressure of the stern seal is reduced so that the lower end of the stern seal does not interfere with the waves on the water surface in the air cushion chamber. (4) Even when the stern seal internal pressure adjusting means is configured as an output adjusting means of an engine for driving an air supply fan for supplying air to the stern seal, the internal pressure of the stern seal is accurately reduced during low speed traveling. Thus, interference between the lower end of the stern seal and the waves in the air cushion chamber is prevented. (5) If a control device is provided for controlling the stern seal internal pressure adjusting means in accordance with a detection signal from the ship speed sensor, adjustment to reduce the stern seal internal pressure during low-speed navigation will be automatically performed, As a result, interference between the lower end of the stern seal and the waves in the air cushion chamber can be appropriately prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a main part of an air cushion ship with stern seal internal pressure adjusting means as a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a main part of an air cushion ship with stern seal internal pressure adjusting means as a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a main part of an air cushion ship with stern seal internal pressure adjusting means as a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a main part of an air cushion ship with stern seal internal pressure adjusting means as a fourth embodiment of the present invention.

FIG. 5 is a perspective view of the air cushion ship as viewed obliquely from below.

FIG. 6 is a longitudinal sectional view showing a main part of a conventional air cushion ship.

FIG. 7 is a graph showing the resistance characteristics of a conventional air cushion ship in plain water as model test results.

FIG. 8 is an explanatory diagram showing a state of a conventional air cushion ship during low-speed navigation.

FIG. 9 is an explanatory diagram showing a state of the air cushion ship of the present invention when traveling at a low speed.

FIG. 10 is a graph showing, as a model test result, resistance characteristics in plain water by adjusting the internal pressure of the stern seal of the air cushion ship of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ship side part 2a Stern seal 2b Bow seal 3 Air cushion room 4,4a Air supply fan 5 Wet deck 6 Air supply port 7,7a Duct 8 Local resistance increase part 9,9a Movable damper 10,10a For air supply fan drive Engine 11, 11a Adjustable inlet guide vane 12 Ship speed sensor 13 Control device 14 Operating mechanism 15 Water surface in air cushion room 15a Wave

Claims (5)

[Claims] 1. An air cushion ship having an air cushion chamber at the lower part of a hull surrounded by both side portions and a flexible stern seal and a bow seal, wherein the stern seal is formed in the shape of an airbag, and In order to prevent waves generated on the water surface in the air cushion chamber from interfering with the lower end of the airbag-shaped stern seal when traveling at a lower ship speed, the air pressure inside the stern seal is lowered. An air cushion ship with stern seal internal pressure adjusting means, characterized in that stern seal internal pressure adjusting means for lowering the air pressure at a speed lower than the planned speed is provided. 2. The stern seal internal pressure according to claim 1, wherein the stern seal internal pressure adjusting means is configured as a movable damper provided in the middle of a duct from an air supply fan to the stern seal. Air cushion ship with adjustment means. 3. The stern seal internal pressure adjustment according to claim 1, wherein the stern seal internal pressure adjusting means is configured as an adjustable inlet guide vane of an air supply fan for supplying air to the stern seal. Air cushion ship with means. 4. The stern seal internal pressure adjusting means is configured as an output adjusting means of an engine for driving an air supply fan for supplying air to the stern seal.
An air cushion ship with a stern seal internal pressure adjusting means according to the above. 5. A control device according to claim 1, further comprising a control device for controlling said stern seal internal pressure adjusting means in accordance with a detection signal from a boat speed sensor. Air cushion ship with stern seal internal pressure adjusting means.