AU2011213824A1 - Rudder resistance reducing method - Google Patents

Abstract

The present invention relates to a rudder resistance reducing method which utilizes a negative pressure to guide in gas for generating air bubbles 50, reducing the resistance of the rudder 14 of a boat 10. The present invention uses an air bubble generator 20 in front of the rudder 14 for generating bubbles 5 during rotation of the propeller 13 of the boat 10 to cause a high-speed flow of water F without changing the original design of the boat 10, enabling the air bubbles 50 to isolate contact between the high-speed flow of water F and the rudder 14, thereby reducing rudder resistance and saving energy consumption. 0 o oo Oo 0g 212 2 20

Description

Regulation 3.2 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: Zuei-Ling Lin Actual Inventor: Zuei-Ling Lin Address for Service: Cl- MADDERNS, GPO Box 2752, Adelaide, South Australia, Australia Invention title: RUDDER RESISTANCE REDUCING METHOD The following statement is a full description of this invention, including the best method of performing it known to me.

RUDDER RESISTANCE REDUCING METHOD BACKGROUND OF THE INVENTION Field of the Invention: The present invention relates to heat sink technology and more particularly, to rudder 5 performance technology and more particularly, to a rudder resistance reducing method, which utilizes a negative pressure to guide in gas for generating air bubbles, reducing the resistance of the rudder of a boat. Description of the Related Art: A boat, except the boat body, has attachments and gears hung on the outside of the boat body. For 0 example, a boat 10 shown in FIG. 1 comprises a boat body 11, a propeller 13 pivotally connected to the boat body 11 below the water line 12, and an attachment, for example, a rudder 14 arranged at the boat 10 at a rear side relative to the propeller 13 for controlling the steering direction of the boat. Referring to FIG. 2, during rotation of the propeller 13 of the aforesaid boat 10, a flow of water is produced that passes through the rudder 14. As the rudder 14 is disposed at the downstream of the 5 flow of water caused by the propeller 13, a resistance will be produced against the steering direction of the board. Further, because the rudder 14 is a requisite attachment of the boat 10, resistance will be inevitably produced against the rudder 14 during rotation of the propeller 13 to cause a high-speed flow of water. Conventional methods for reducing the aforesaid resistance are commonly to modify the 0 streamline design of the rudder or surface treatment without affecting the structural strength of the rudder. However, these methods cannot achieve a significant effect in reducing the rudder resistance. Therefore, it is desirable to provide a measure for reducing rudder resistance in an economic manner, minimizing fuel gas consumption. SUMMARY OF THE INVENTION 25 The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a rudder resistance reducing method, which uses an air bubble generator in front of the rudder for generating bubbles during rotation of the propeller of the boat to cause a high-speed flow of water without changing the original design of the boat, enabling the air bubbles to isolate contact between the high-speed flow of water and the rudder, thereby reducing 30 rudder resistance and saving energy consumption. To achieve the main object, a rudder resistance reducing method comprises the steps of: a) providing a boat comprising a propeller rotatable to drive the boat to steer and a rudder 2 installed in the boat body at a rear side relative to the propeller; b) installing an air bubble generator in the boat at a front side relative to the rudder, the air bubble generator comprising an air tube arranged at the water face of the rudder and defining at least one gas inlet and opposing pairs of gas release outlets; 5 c) providing a gas guide device comprising at least one guide pipe, the at least one guide pipe having a bottom end thereof connected to the at least one gas inlet of the air tube and a top end thereof terminating in an intake hole; d) employing Bernoulli's principle to produce a negative pressure in the gas release outlets for sucking in outside air for generating air bubbles during rotation of the propeller to cause a high-speed 0 flow of water; e) enabling the intake flow of air or gas to be guided by the at least one guide pipe into the at least one gas inlet of the air tube and then discharged out of the gas release outlets to mix with water and to produce multiple air bubbles; and f) utilizing the air bubbles thus produced to isolate a part of the high-speed flow of water and 5 the rudder and to reduce friction contact between the high-speed flow of water and the rudder and to further reduce the resistance of the rudder against the high-speed flow of water. Further, a gas guide device is used for guiding air or gas into the air bubble generator. The gas guide device uses a supplementary measure to guide engine waste gas or low pressure gas from the steam turbine into the gas guide device for generating air bubbles. 0 Further, the gas guide device further compresses a pressure device for pumping a gas into the gas guide device. The pressure device can be selected from an air compressor, an air blower, an engine, a steam turbine and a turbo of the boat. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic drawing illustrating an arrangement of a rudder in a conventional boat. 25 FIG. 2 is a schematic drawing illustrating a flow of water caused and passed over the rudder during rotation of the propeller according to the prior art. FIG. 3 is a schematic drawing illustrating air bubbles generated in the flow of water caused and passed over the rudder during rotation of the propeller in accordance with the present invention. FIG. 4 is a schematic drawing illustrating the arrangement of the gas guide device in the boat 30 in accordance with the present invention. FIG. 5 is a sectional view taken in an enlarged scale along line 5-5 of FIG. 4. FIG. 6 is an enlarged view of the major part which is No. 6 of FIG. 5, illustrating generation of 3 air bubbles in the negative pressure. FIG. 7 is an exploded elevational view of the air bubble generator shown in FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Further features and benefits of the present invention will be apparent from the following 5 detailed description of the preferred embodiment taken in conjunction with the annexed drawings. However, it is to be understood that the invention is applicable to any of a variety of boats. The present preferred embodiment is simply an example but not a limitation. Referring to FIGS. 3 to 6, when compared to the surface resistance of the rudder 14 of the prior art design shown in FIG. 2, multiple air bubbles 50, as shown in FIG. 3, are generated in the flow 0 of water that is produced during steering of the board to reduce rudder resistance. The rudder resistance reducing method in accordance with the preferred embodiment of the present invention, as shown in FIGS. 4 and 5, comprises the steps of: a) providing a boat 10 comprising a boat body 11, a propeller 13 pivotally mounted in the boat body 11, a power engine 131 for rotating the propeller 13 to cause a high-speed flow of water F, and a 5 rudder 14 installed in the boat body 11 at a rear side relative to the propeller 13; b) installing an air bubble generator 20 in the boat body 11 at a front side relative to the rudder 14, wherein the air bubble generator 20, as shown in FIGS. 6 and 7, comprises an air tube 21, which is, for example, but not limited to, a circular tube arranged at the water face of the rudder 14 and defines at least one gas inlet 211 and opposing pairs of gas release outlets 212 in, for example, circular shape; 0 the air tube 21 can be formed integral with the rudder 14 and processed to provide the gas release outlets 212 during fabrication of the boat 10, or alternatively, the air tube 21 can be separately made and then affixed to the water face of the rudder 14 without destructing the structural strength of the rudder 14; c) providing a gas guide device 30, which, as shown in FIG. 4, comprises at least one guide 25 pipe 31 that has its bottom end connected to the at least one gas inlet 211 of the air tube 21 and its top end terminating in an intake hole 32 that is disposed in the boat body 11 or above the water line 12; d) employing Bernoulli's principle to produce a negative pressure in the gas release outlets 212 for sucking in outside air for generating air bubbles 50 during rotation of the propeller 13 and steering of the boat body 11 to cause the aforesaid high-speed flow of water F that strikes the water 30 face of the rudder 14; as the high-speed flow of water F flows at a high speed during rotation of the propeller 13, a high negative pressure can be produced in the gas release outlets 212 to suck in outside air for generating air bubbles 50 without power consumption; e) enabling the intake flow of air to be guided by the at least one guide pipe 31 into the at least 4 one gas inlet 211 of the air tube 21 and then discharged out of the gas release outlets 212 to mix with water and to produce multiple air bubbles 50; and f) utilizing the air bubbles 50 thus produced, as shown in FIG. 3, to isolate a part of the high speed flow of water F and the rudder 14 and to reduce friction contact between the high-speed flow of 5 water F and the rudder 14 and to further reduce the resistance of the rudder 14 against the high-speed flow of water that is produced during rotation of the propeller 13. As the resistance of water is about 700 to 800 times greater than air, using the air bubbles 50 to reduce contact between the high-speed flow of water F and the rudder 14 can effectively reduce the resistance, the more the isolation of the contact between the high-speed flow of water F and the rudder 0 14 the better the resistance reducing effect will be. Based on the aforesaid technical measure for generating air bubbles 50, the invention simply needs to install an air bubble generator 20 in front of the rudder 14 without using any power drive or changing the original design of the boat. Referring to FIG. 4, the existing resources of the boat body I1 may be utilized for pumping air 5 or gas into the at least one guide pipe 31 of the gas guide device 30, for example, a pressure device 34 may be connected to the at least one guide pipe 31 of the gas guide device 30 and a control valve 33 may be set between the at least one guide pipe 31 and the pressure device 34. The pressure device 34 is adapted for pumping air, engine waste gas or waste gas from the steam turbine in the boat body 11 into the at least one guide pipe 31. 0 Further, the pressure device 34 can be the existing air compressor, air blower, engine or steam turbine in the boat body 11. The resource recycling of directly guiding the waste gas from the engine or steam turbine of the boat 10 does not require any extra resources or increase the cost. Further the waste gas from the engine or steam turbine can also be used to drive a turbo for pumping air or gas toward the gas release outlets 212. Further using an air flow or the like to make the pressure device 34 25 requires less power to pump air or gas for generating air bubbles 50 that isolate contact between the high-speed flow of water F and the rudder 14 to reduce rudder resistance. Thus, using a small amount of power can achieve multiple times of power. Further, the pressure device 34 can be prepared by using existing resources to directly guide air or gas or to compress air or gas into the gas release outlets 212. 30 In conclusion, by means of arranging an air bubble generator 20 in the boat body 11 at a front side relative to the rudder 14 and employing the Bernoulli's principle in hydrodynamics that an increase in the velocity of a stream of fluid results in a decrease in pressure, the invention guides in air or gas to generate air bubbles 50 for isolating contact between the high-speed flow of water F and the rudder 14 to reduce rudder resistance. 35 Although a particular embodiment of the invention has been described in detail for purposes of 5 illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. 6

Claims (4)

1. A rudder resistance reducing method, comprising the steps of: a) providing a boat 10 comprising a propeller 13 rotatable to drive said boat 10 to steer and a rudder 14 installed in a boat body 11 at a rear side relative to said propeller 13; 5 b) installing an air bubble generator 20 in said boat 10 at a front side relative to said rudder 14, said air bubble generator 20 comprising an air tube 21 arranged at the water face of said rudder 14 and defining at least one gas inlet 211 and opposing pairs of gas release outlets 212; c) providing a gas guide device 30 comprising at least one guide pipe 31, said at least one guide pipe 31 having a bottom end thereof connected to said at least one gas inlet 211 of said air tube 0 21 and a top end thereof terminating in an intake hole 32; d) employing Bernoulli's principle to produce a negative pressure in said gas release outlets 212 for sucking in outside air for generating air bubbles 50 during rotation of said propeller 13 to cause a high-speed flow of water F; e) enabling the intake flow of air/gas to be guided by said at least one guide pipe 31 into said 5 at least one gas inlet 211 of said air tube 21 and then discharged out of said gas release outlets 212 to mix with water and to produce multiple air bubbles 50; and f) utilizing the air bubbles 50 thus produced to isolate a part of the high-speed flow of water F and said rudder 14 and to reduce friction contact between the high-speed flow of water F and said rudder 14 and to further reduce the resistance of said rudder 14 against the high-speed flow of water F. 0

2. The rudder resistance reducing method as claimed in claim 1, wherein the intake hole 32 at the top end of said at least one guide pipe 31 is disposed in the boat 10 or above the water line 12.

3. The rudder resistance reducing method as claimed in claim 2, wherein said gas guide device 30 uses a supplementary measure to guide engine waste gas or low pressure gas from the steam turbine into said at least one guide pipe 31 of said gas guide device 30 for generating air bubbles 50. 25

4. The rudder resistance reducing method as claimed in claim 3, wherein said gas guide device 30 further compresses a pressure device 34 for pumping a gas into said at least one guide pipe 31 toward said at least one gas release outlet 212, said pressure device 34 being selected from an air compressor, an air blower, an engine, a steam turbine and a turbo of the boat 10. 7