KR101045044B1 - Improved Air Check Valve Assembly Construction of Controllable Pitch Propeller System - Google Patents

Abstract

The present invention relates to an air check valve assembly structure of a variable pitch propeller to which an air discharge system is applied, and an object of the present invention is to enable quick and simple assembly and disassembly of an air check valve without disassembling various components in the hub.

Adjustable Pitch Propeller, Air Release System, Air Check Valve

Description

Improved Air Check Valve Assembly Construction of Controllable Pitch Propeller System

The present invention relates to an improved air check valve assembly structure of a variable pitch propeller to which an air discharge system is applied.

1. Adjustable pitch propeller

The variable pitch propellers are individually connected to the hubs with wings on one axis, and the pitch of the wings can be arbitrarily changed by the interlocking device in the hub while the propellers are rotating. Even if the direction of rotation does not change, it is possible to give a reverse thrust, that is, a negative pitch.

The main advantage of the variable pitch propeller from the ship's point of view is that the propeller's pitch can always be adjusted to suit the conditions of severely changing ships, such as qualifiers, trolleys, pilots and small minesweepers. For example, by reducing the pitch of the propellers when the tug is navigating or when the trolley is dragging the net, the advantage is that the engine can be operated at full speed, and therefore at full power, without increasing the average effective pressure in the cylinders of the main engine. have. This is especially important for diesel engines. In addition, there is an advantage that the forward speed is possible by adjusting the pitch of the propeller negatively while the main engine always rotates in the same direction in the conducting wire which has to repeat the forward, stop and reverse motions. Also, from the engine's point of view, such a propeller can save weight and cost by eliminating the need for reversing gears in reciprocating engines or reversing turbines in turbine-propelled vessels, and can reverse thrust even faster in an emergency. Has an advantage.

Variable pitch propellers can be as efficient as integrated propellers with fixed blades in any particular navigational state of normal navigation, except that they have rather large hubs to accommodate pitch adjustments.

The servo motors in the arrangement of US Patent 4,563,940 are arranged in the holes of the housing components and operate via a hollow intermediate shaft which is a rotating body. The two oil supply passages of the housing component are connected under the control of the oil supply and the oil hole is opened by the circumferential annular passage of the intermediate shaft. Each annular passageway has two axial intermediate cross-sectional shapes in the form of an oil distributor ring supported on the intermediate shaft. The oil distributor ring is assembled and sealed in the housing component by an annular sealing device along the outer diameter circumference of each of the two annular passages. Each annular or ring shaped passage is connected to the servomotor chamber via a connecting passage or channel formed in the working space or intermediate shaft.

According to U.S. Patent 4,907,992, a marine variable pitch propeller with a main servomotor in the hub for controlling the pitch of the rotating propeller blades has a tubular valve rod connected to the propeller shaft via an auxiliary servo to the oil distributor box housing. Operation to determine the direction of oil supply of the main servomotor in the hub, which moves the piston in the servochamber to actuate the blade pitch. The oil is annular between the shaft and the valve rod by means of an evenly spaced seal, such as an oil hole in the valve rod and an oil opening in the shaft and a gap between the oil distributor box housing and the shaft of the bearing journal that matches the opening of the shaft. It is fed to the valve rod through the oil supply chamber.

A description of the oil distributor box in Keith Brownlie's variable pitch propeller book (Figure 21. Marine Engineers Laboratories, 1998, page 43) describes an oil distributor box installed at the end of all gears connected by double hydraulic lines. . The double hydraulic pipe is inserted into the oil distributor bush, which is combined with the stab shaft and has a seal and bearing function. In addition, the oil distributor bush is connected to the oil supply and return passage through the rotary ring pipe and the hinge, which is a hydraulic passage. The feedback system is transmitted to the rod and shaft connection under the oil distributor bush. The feedback shaft is connected by a link to a potentiometer indicating the pitch angle, which is sent to a hydraulic control valve installed in the hydraulic unit.

2. Air Emission System of Variable Pitch Propeller

Propeller noise comes from propeller operation and propulsion outside the hull. The main root cause of propeller noise is cavitation noise caused by the explosion of water vapor produced by the rotation of the propeller blades. On ships with fixed pitch propellers, this noise occurs at speeds faster than speeds in the 9 to 15 Knots range, which is called the Cavitation Inception Speed. Vessels with variable pitch propellers generate cavitation at both high and low speeds. Another important form of propeller noise is "sound" caused by propeller blade resonance. Sound usually occurs only within a narrow range of the ship's speed.

The air release system supplies air along the propeller blade entry to reduce the hydrodynamic noise from the propeller. The system allows the bubbles created by cavitation to shrink more slowly when the pressured area is minimized, filling the vacuum left by the rotating blades as when water "boils." After passing through the propulsion shaft through the propulsion system to the propeller hub, it is released through the small holes in the propeller blades, each engine room has a Prairie air system that supplies air to the combined propellers. Suppress noise and cavitation as it passes through a hole along the leading edge of the

The chiller uses seawater from the air discharge system as the cooling medium. The prairie air from the cooler passes through the flow meter into the rotor seal of the oil distributor box (OD-Box) and through the prairie air line to the propeller. Air enters the tube through the hub body behind the propeller hub. These tubes direct air to the base of each propeller blade. Air reaches each blade through a bushing connection between the base of the blade and the hub body. Air is then blown out through the air passage in front of the blade through the 302 orifice. When the air supply is assured, two check valves block water from entering. The fin ballast uses prairie air supplied directly from the outlet of the prairie air cooler.

In general, noise measurement in cavitation is only external monitoring. However, the procedure to measure the cavitation initial speed allows for internal monitoring of the noise. The relationship between the ship's operating speed and cavitation noise is an important factor. In the first 24 hours after long anchoring, the blade's performance is degraded, so the cavitation noise increases as the propeller's operating time increases. By introducing air or other gas into the propeller flow of the ship, it is possible to accurately identify turbulences, flow rates, and flow rates in different operating situations, and to obtain a process that can be easily controlled. The turbulent flow of the propeller flow thus obtained is used to make the gas bubbles formed into small bubbles and to mix them effectively with water as needed. Thus the number and size of bubbles can be easily adjusted as needed.

In order to achieve effective noise reduction, it is very important to form a large number of bubbles of 1-20 mm diameter in water. These tiny bubbles do not rise quickly above the surface of the water and stay underwater, usually spreading out in a relatively large area of water, more than 100 meters from the ship. From the point of view of effective noise reduction, the better bubble area should primarily contain a sufficient amount of bubbles with a diameter of about 100 mm. These large bubbles are created by the gas introduced underwater through large nozzles in the edge region or the outer region in the propeller flow.

The amount of air or other gas released into the water is most appropriately controlled by correlating the propeller passage speed. Due to the well-known propeller characteristics such as propeller diameter, pitch and turnover in various situations, the propeller passage speed can be easily calculated.

Nuclear mechanics and cavitation parasitic noise occur at the propeller inlet edge. Their orbits, volumes, changes, and sonic signals can be estimated using the surface average pressure of the spherical air bubble dynamics model. Calculations of bubble mechanics based on general research are carried out in a defined steady flow state, which is applied to the propeller flow environment through time-dependent nuclei circulating convection. In order to achieve the satisfactory instantaneous pressure effect of the nucleus, the energy model of the bubble and the Navier-Stokes Solver must be applied at each stage. The statistical nuclear distribution model described is also used to study the beginning of cavitation with stochastic results.

The most effective noise reduction can be achieved by installing propellers or propellers on the bow of the ship and introducing gas directly behind each propeller. This forms and surrounds a gas bubble area throughout the hull under the sea, thereby forming a noise reduction bubble area around all noise sources of the vessel.

On the other hand, it is sometimes necessary to replace the air check valve in the variable pitch propeller to which the air release system is applied.In the case of the conventional variable pitch propeller, in order to replace the air check valve, various parts in the hub must be disassembled. A difficult problem arises.

The present invention has been proposed to solve the above problems, and by improving the assembly structure of the air check valve in the variable pitch propeller to which the air discharge system is applied, the air check valve is simply disassembled without disassembling the components in the hub. The aim is to be able to disassemble and assemble easily and quickly.

Other objects and advantages of the present invention will be described below, which are not limited to the matters set forth in the claims and the disclosure of the embodiments thereof, but also to the broader ranges by means and combinations within the range readily recited therefrom. Add that it will be included.

In order to achieve the above object, the present invention allows the air check valve to be assembled at the position where the trunnion and the blade flange are in contact, so that the air check valve can be quickly and simply assembled and disassembled without disassembling the various components in the hub. An improved air check valve assembly structure of a variable pitch propeller is presented.

According to the present invention, in the variable pitch propeller to which the air release system is applied, the air check valve can be easily and quickly disassembled and assembled simply by disassembling the blade without disassembling the components in the hub.

Other effects of the present invention, as well as those described in the above-described embodiments and claims of the present invention, as well as potential effects that may occur within the range that can be easily estimated therefrom and potential advantages that contribute to industrial development It will be added that it will be covered by a wider scope.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, the following will describe a preferred embodiment of the present invention, but the technical idea of the present invention is not limited thereto and may be variously modified and modified by those skilled in the art.

FIG. 1 shows what is before (a) and after (b) the improvement of the assembly structure of the air check valve 11 in the variable pitch propeller to which the air release system is applied.

Before improvement (a) The air check valve 11 was assembled in the position A where the trunnion 12 and the actuating rod 13 contact.

Therefore, in order to disassemble the air check valve 11 before improvement (a), not only the blade 1 and the blade bolt 2 but also the fairing cone 9 and the propeller cap Cap (8) must be disassembled from Hub Body (10), Joint Link (7), Fitting Pin (3), Crank Ring (5), Trunnion nut (6) must be disassembled so that the trunnion (Trunnion) 12 can be disassembled in the hub body (Hub Body) (10) was not able to disassemble the air check valve (11).

However, if the assembly structure of the air check valve 11 is improved as in the present invention, the situation is completely different.

After improvement (b) the air check valve 11 is assembled at a position B where the trunnion 12 and the blade flange 14 abut.

Therefore, after improvement (b), the air check valve 11 can be disassembled only by disassembling the blade 1 and the blade bolt 2. That is, according to the present invention, the air check valve 11 can be easily and quickly disassembled and assembled without disassembling other components in the hub.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

FIG. 1 shows what is before (a) and after (b) improving the assembly structure of the air check valve 11 in a variable pitch propeller to which an air release system is applied.

<Description of Major Symbols in Drawing>

1: Blade

2: Blade Bolt

3: Fitting Pin

5: Crank Ring

6: Trunnion Nut

7: Joint Link

8: Propeller Cap

9: Fairing Cone

10: Hub Body

11: Air Check Valve

12: trunnion

13: Actuating Rod

14: Blade Flange

A: Location of air check valve before improvement

B: position of air check valve after improvement

Claims (1)

By assembling the air check valve 11 at the position B where the trunnion 12 and the blade flange 14 contact each other, the air check valve 11 can be quickly and simply assembled without disassembling various components in the hub. Improved air check valve assembly with variable pitch propellers for disassembly.

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