KR20140129294A - Arrangement and method in a ship - Google Patents

Abstract

The ship comprises a hull (200) and at least one propulsion unit (100) comprising a propulsion engine (30), a transmission means (40), at least one propeller connected to the propulsion engine (30) (50), a vibration sensor (300) positioned near at least one propeller (50) for sensing vibration caused by cavitation of the at least one propeller (50), at least one propulsion unit ). The apparatus further comprises a control unit (400) for controlling at least one propulsion engine (30), wherein the vibration sensor (300) is connected to a control unit (400) ) Determines whether or not a worse degree of cavitation is present and indicates that a worse degree of cavitation is present on the display unit at the navigation bridge and / or at least when a worse degree of cavitation appears Is analyzed in the control unit (400) to adjust the rotational speed and / or power of one propulsion engine (30).

Description

[0001] ARRANGEMENT AND METHOD IN A SHIP [0002]

The invention relates to an arrangement in a ship according to the preamble of claim 1.

The invention also relates to a method in a ship in accordance with the preamble of claim 12.

The apparatus and method include a hull, at least one propulsion engine, transmission means, at least one propeller connected to at least one propulsion engine via transmission means, and an upper portion, a lower portion, and a front edge supported by the hull And a control unit for controlling at least one propulsion engine.

The ship may have one propulsion engine or two or more propulsion engines located at the stern of the ship. The propeller may include a single propeller or two contra-rotating propellers.

The device is particularly suited for use in large vessels, such as cruisers, tankers transporting oil or liquefied natural gas, vehicle transport vessels, container vessels and ferries.

JP Patent Publication 2004182096 discloses a pod-type propulsion device including a support structure pivotably attached to the hull of a ship, and a chamber attached to the support structure. The chamber includes a motor connected to the first end of the shaft, the second opposite end of the shaft projecting from the front end of the chamber and connected to the propeller. The rotation angle of the support structure is limited when the speed of the ship increases to prevent cavitation.

RU Patent Publication 2009957 discloses a device for reducing cavitation in a ship. The propeller at the rear of the ship is connected to the motor in the hull of the ship via the shaft. There is a flexible case with a vibrating drive on the blade of the propeller. The cavitation noise sensor is located on the ship's hull. The vibration frequency control block for the flexible case is connected in series with the noise sensor. A propeller shaft is provided with a collector having a brush. The sensor generates a signal proportional to the acoustic radiation and supplies it as an input signal to the vibration frequency control block. The vibration frequency control block again generates a return signal to the drive for a flexible vibration case to minimize cavitation noise.

JP Patent Publication No. 09136694 discloses automatic speed control of a water jet pump used in a ship. The pressure sensor detects the transfer pressure of the water jet pump as the vessel moves. The calculator calculates the number of rotations that can be applied to the water jet pump to avoid cavitation generation in the water flow based on the output signal of the pressure detector. The signal selector compares the calculated number of revolutions with the number of revolutions displayed by the steering control unit. The signal selector outputs a control signal to the drive motor of the water jet pump by selecting a signal indicating a smaller number of rotations.

JP Patent Publication No. 09109991 discloses a marine pin ballast of the anti-cavitation type. The ballast includes pins that are pivotally supported on the hull through a shaft. The pin drive mechanism adjusts the blade angle of the pin by rotating the shaft. The water discharge nozzle at the lower rear edge of the pin controls the cavitation generation of the pin during cruising. The feed water pump supplies water and discharges water from the discharge nozzle. The underwater microphone located behind the pin detects the noise caused by the cavitation of the pin. The water injection controller controls the water injection from the discharge nozzle by controlling the supply pump based on the noise detection signal of the microphone.

Cavitation occurs when the liquid changes its phase to vapor in a particular flow region where the local pressure is very low due to the high local velocity. At least four different cavitation types associated with rotating propellers in water are: a) tip vortex from the suction side, considered normal operation until a certain level is exceeded, b) sheet cavitation at the suction side, c ) Tip vortex from the pressure side, and d) bubble cavitation.

The control bridge is at the stern of the ship, ie 200 to 400 meters from the rear of the large ship. The control bridge is also 15 to 40 meters above sea level. This means that the captain or sailor placed on the sailing bridge does not usually feel or hear the cavitation caused by the propeller at the rear of the ship. Therefore, it is necessary to allow the captain and / or the navigator to recognize the situation in which a worse degree of cavitation occurs. Such a situation can generally occur when the ship is suddenly accelerated to full power, or when the propulsion unit and / or the ship is rotated at a large rotational angle.

It is an object of the present invention to provide an apparatus and a method for managing a situation in which cavitation occurs in a ship.

The device in a vessel according to the invention is characterized by the features in the characterizing part of claim 1.

The method in a vessel according to the invention is characterized by the features in the characterizing part of claim 12.

The apparatus in a vessel according to the invention comprises at least one propeller connected to the propulsion engine via a hull and a propulsion engine, transmission means, and transmission means, and at least one propeller for sensing vibration caused by cavitation of the at least one propeller. And a vibration sensor positioned near the propeller. The apparatus further comprises a control unit for controlling at least one propulsion engine, wherein the vibration sensor is connected to a control unit, and the output signal of the vibration sensor determines whether a worse degree of cavitation is present, Of cavitation appears on the display unit at the navigation bridge and / or is analyzed in the control unit to adjust the rotational speed and / or power of at least one propulsion engine when a worse degree of cavitation appears.

It is easier to recognize the cavitation of the propeller when the vibration sensor is located near the origin of the phenomenon, i.e. near the propeller. When the propulsion unit is about to enter into an unnecessary operation with detrimental further deterioration of cavitation, the control unit sends a warning to the display unit at the navigation bridge and / or controls the speed and / or power of the propulsion engine.

When a direct measurement is made from the vibration caused by the cavitation of the propeller, the amount of rotation parameter in the system is limited to a minimum. The only rotation parameters are the sensitivity at the propeller blade frequency, the type and amplitude of the burst. The signal processing of the raw measurement is also rather simple, which means that the display of the cavitation in the worse case is fast. The speed ramp of the propulsion unit is typically relatively low, which means that it takes a long time to react before more severe cavitation appears.

The first stage tip vortex cavitation is normal in operation, for example when the vessel is driven at total speed. The first stage tip vortex is also typically considered a hydrodynamic design and the operating efficiency of the propeller is not detrimentally affected by the first stage tip vortex. If cavitation is getting worse, it will be detrimental to the entire propulsion machinery and can cause instantaneous or long-term damage. The worse class of cavitation will cause the propeller efficiency to drop, which dramatically reduces the maneuverability of the ship.

The best position of the vibration sensor for sensing the tip vortex of the propeller is on the support structure located behind the propeller in the direction of drive of the vessel at the point where the tip vortex "rope" hits the support structure. The support structure is in the propulsion unit of the normal pulling type, i.e. behind the propeller in the propulsion unit where the propeller is at the front end of the chamber.

The support structure creates different densities in a hydrodynamic environment as the propeller blades pass in front of the support structure. The tip vortices and support structure influence together. The interaction between the tip vortex and the support structure will create a propeller blade frequency burst when the tip vortex becomes worse. These points are the boundaries for initiating action in propulsion control to avoid more severe cavitation.

It may be possible to disable the control unit in a specific state by means of individual buttons on the steering bridge.

The present invention may advantageously be used in large ships, for example, cruisers, oil tanks for transporting oil or liquefied natural gas, vehicle transit vessels, container vessels and ferries. The power of the propulsion unit in such large ships is at least about 1 MW.

Some specific embodiments of the invention are described in more detail below with reference to the accompanying drawings.

The present invention is effective for managing a situation in which cavitation occurs in a ship.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a device according to the invention in a ship comprising a pod propulsion unit.
Figure 2 shows a device according to the invention in a ship comprising a rudderpod unit;
3 shows a device according to the invention in a ship comprising a conventional axial propulsion unit.

1 shows an apparatus according to the invention in a ship with a pod propulsion unit.

The apparatus comprises a propulsion unit (100) located at the rear of the vessel. The propulsion unit 100 includes a propulsion engine that includes a support structure 10, a chamber 20, a first electric motor 30, a shaft 40, and a propeller 50. The support structure 10 has an upper portion 11, a lower portion 12, a front edge 13, and a rear edge 14. The upper portion 11 of the hollow support structure 10 is pivotally attached to the hull 200 of the ship. The chamber 20 is fixedly attached to the lower portion 12 of the hollow support structure 10. The shaft 40 has a first end connected to the first electric motor 30 and a second end projecting from the front end 21 of the chamber 20 and connected to the propeller 50. The propeller 50 is thus located at the front end 21 of the chamber 20. The first electric motor 30 may be an induction motor or a synchronous motor. The propeller 50 may comprise a single propeller or two reversing-rotating propellers. The driving direction of the ship is shown by the arrow S1 in the figure.

The propulsion unit 100 further includes a rotation mechanism 60 for rotating the propulsion unit 100 in relation to the ship's hull 200 about the axis of rotation Y-Y. The rotary mechanism 60 is located in the hull 200 of the ship and includes a gear rim 61 and a second electric motor 62. The shaft 63 of the second electric motor 62 is connected to the pinion gear 64 and the pinion gear 64 is connected to the circumference of the gear rim 61. The upper portion 11 of the support structure 10 is connected to the gear rim 61. The second electric motor 62 rotates the pinion gear 63 such that the pinion gear 63 rotates the gear rim 61 and the gear rim 61 rotates the support structure 10 Thereby rotating the propulsion unit 100. The second electric motor 62 may be an induction motor or a synchronous motor. Two or more second electric motors 62 positioned around the circumference of the gear rim 61 can be naturally located.

The apparatus also includes a control unit 400 that controls at least the first electric motor 30, and, alternatively, the second electric motor 62 as well. The control unit 400 will control the first electric motor 30 and the second electric motor 62 based on an instruction from the navigation bridge. The rotational speed of the electric motors 30, 62 may be controlled by, for example, a frequency converter.

The apparatus for cavitation display further comprises a vibration sensor (300) located on the front edge (13) of the support structure (10). The vibration sensor 300 has a height corresponding to the position of the tip of the blade 50 of the propeller 50 in the situation where the tip of the blade of the propeller 50 passes during the rotational movement in front of the front edge 13 of the support structure 10 On the front edge (13) of the support structure (10). The vibration sensor 300 is connected to the control unit 400. This position of the vibration sensor 300 is optimal in view of sensing the tip vortex generated by the rotating propeller 50 in particular.

Figure 2 shows a device according to the invention in a vessel comprising a rudder pod unit.

The apparatus comprises a propulsion unit (100) located at the rear of the vessel. The propulsion unit 100 includes a propulsion engine including a support structure 10, a chamber 20, a first electric motor 30, a shaft 40, a propeller 50, and a rudder 70 . This arrangement corresponds to the pod arrangement of Figure 1 except for the rudder 70, in that the support structure 10 is in a rudder pod fixedly supported on the hull 200 of the ship. The rudder 70 is pivotally supported about the rotation axis Y-Y.

3 shows a device according to the invention in a ship comprising a conventional axial propulsion unit. This device does not have a pod device outside the ship's hull (200). The propulsion unit 100 includes a propulsion engine 30 in the hull 200 of the ship and a first end connected to the propulsion engine 30 and a first end extending through the opening at the rear end of the hull 200, And a shaft (40) having a second end connected to an externally located propeller (50). The propulsion engine 30 may be, for example, a diesel engine or an electric motor. The rudder 70 is positioned behind the propeller 50 in the direction of the ship's running S1. The rudder 70 is further pivotally supported about the rotation axis Y-Y.

The vibration sensor 300 is mounted on the tip of the blade 50 of the propeller 50 in the situation when the tip of the blade 50 of the propeller 50 passes during the rotation of the support structure 70, i.e. the forward edge 71 of the rudder 70, Is positioned on the front edge 71 of the rudder 70 at a height corresponding to the position. The vibration sensor 300A may alternatively be attached to the lower portion of the hull 200 of the ship as shown also in the figures. The position of the vibration sensor 300A on the hull 200 will be in the radial direction on the tip of the blade of the propeller 50 in such a case.

It is advantageous to have the vibration sensor 300 attached to the support structure, which is located behind the propeller 50 in the direction of the ship's drive. The vibration sensor 300 will effectively sense the tip vortices of the propeller 50, particularly at such locations. A support structure suitable for attaching the vibration sensor 300 is, for example, a support structure for a pod or a rudder, but may be any support structure located behind the propeller 50 in the direction of drive S 1 of the craft. In the case of a pod unit having a propeller 50 at the rear end of the chamber 20, an individual support structure is required behind the pod for the vibration sensor 300.

The propeller 50 may be formed from a single propeller or two reversing-rotating propellers.

The vibration sensors 300 and 300A may be, for example, pressure sensors, acoustic sensors, or acceleration sensors.

When the vibration sensor 300 is positioned on the support structure 10, 70 behind the propeller 50 in the direction of the ship's running S1, the optimal position is when the tip of the blade is in the uppermost position, Which corresponds to the height of the blade tip. The permissible vertical deviation V1 from the base height position is less than +/- 25% of the diameter D1 of the propeller 50. [ The vibration sensor 300 located on the support structure 10, 70 behind the propeller 50 measures the cavitation propagating back from the propeller 50.

When the vibration sensor 300A is positioned on the hull 200 on the propeller 50 in the radial direction, the basic longitudinal position is just above the tip of the propeller 50 exactly when the tip of the blade is in the topmost position . The allowed horizontal deviation H1 of the basic longitudinal position is not more than 50% of the diameter D1 of the propeller 50. [ A vibration sensor 300A positioned radially above the propeller 50 measures the cavitation propagating in the radial direction from the propeller 50. [

The vibration sensors 300, 300A should be positioned to be sensitive to cavitation emerging from the propeller 50.

The control unit 400 may be an individual unit or it may be integrated into several other control units in the ship.

The present invention can also be implemented in a ship having two or more propulsion units. For example, a ship with two propulsion units at the stern of a ship requires a vibration sensor for each propeller and a control circuit for each propulsion motor.

The foregoing examples of embodiments of the present invention are not intended to limit the scope of the present invention to these embodiments only. Various modifications to the invention may be made within the scope of the claims.

Claims (12)

As a device in a ship,
- a hull (200)
At least one propulsion unit (100) comprising at least one propeller (50) connected to a propulsion engine (30) via a propulsion engine (30), a transmission means (40) and a transmission means (40) At least one propulsion unit (100)
- a vibration sensor (300) located near at least one propeller (50) for sensing the vibration caused by the cavitation of at least one propeller (50)
A device in a ship, comprising:
- a control unit (400) for controlling at least one propulsion engine (30), said vibration sensor (300) comprising a control unit (400) connected to a control unit
Further included,
The output signal of the vibration sensor 300 determines whether a worse degree of cavitation is present and indicates that a worse degree of cavitation is present on the display unit at the navigation bridge and / Is analyzed in the control unit (400) to adjust the rotational speed and / or power of the at least one propulsion engine (30) when it appears. 2. A method as claimed in claim 1, wherein the vibration sensor (300) is attached to a front edge (14, 71) of a supporting structure (10, 70) projecting downwardly from the hull (200) Is located behind the propeller (50) in the direction of movement (S1) of the ship. 3. A method as claimed in claim 2, wherein the vibration sensor (300) is arranged such that when the tip of the blade is in its uppermost position, the vibration sensor (300) Characterized in that a vertical deviation (V1) of less than +/- 25% of the diameter (D1) of the propeller (50) is permitted from the basic height position, while the vertical deviation (V1) is located on the front edge (14, 71). The apparatus according to claim 1, characterized in that the vibration sensor (300A) is located below the hull (200) at a position above the propeller (50). 5. A method according to claim 4, wherein the vibration sensor (300A) is located radially above the propeller (50) at a basic longitudinal position just above the tip of the blade of the propeller (50) exactly when the tip of the blade is in its uppermost position, Characterized in that the horizontal deviation (H1) of the basic longitudinal position of not more than 50% of the diameter (D1) of the propeller (50) is allowed from the basic longitudinal position. The method according to claim 1,
A support structure 10 rotatably supported on the hull 200 around the rotation axis YY and including a hollow body,
At least one second electric motor (62) for rotating the support structure (10) so that a rotation mechanism (60) including a chamber (20) for the ship's hull (200) ), While < RTI ID = 0.0 >
At least one propulsion engine 30 comprises a first electric motor 30 located in a chamber 20 having a front end 21 and a rear end 22, 10, which is fixedly attached to the lower portion 12 of the housing 10,
The transmission means 40 comprises a shaft 40 having a first end and a second end and the first end of the shaft 40 is connected to a first electric motor 30, The second end projects from the front end 21 of the chamber 20 and is connected to at least one propeller 50,
Characterized in that the vibration sensor (300) is located at the front edge (11) of the support structure (11) behind at least one propeller (50) in the direction of the ship's running (S1). The method according to claim 1,
A support structure 10 fixedly attached to the hull 200 and including a hollow body,
A rudder 70 positioned behind the support structure 10 and the chamber 20 in a direction S1 of the ship in which the rudder 70 is pivotally supported on the hull 200 about the axis of rotation YY , And a rudder 70,
The propulsion engine 30 comprises a first electric motor 30 located in a chamber 20 having a front end 21 and a rear end 22, Fixedly attached to the lower portion 12,
The transmission means 40 comprises a shaft 40 having a first end and a second end and the first end of the shaft 40 is connected to a first electric motor 30, The second end projects from the front end 21 of the chamber 20 and is connected to the propeller 50,
Characterized in that the vibration sensor (300) is located at the front edge (11) of the support structure (11) behind at least one propeller (50) in the direction of the ship's running (S1). The method according to claim 1,
A rudder 70 rotatably supported on the hull 200 about a rotational axis YY and having a rudder 70 positioned behind the propeller 50 in the direction S1 of the ship, In addition,
- the propulsion engine (30) comprises a first electric motor or diesel engine (30) located in the hull (200) of the ship,
The transmission means 40 comprises a shaft 40 having a first end and a second end and the first end of the shaft 40 is connected to a propulsion engine 30, The two ends project from the rear end of the hull 200 and are connected to the propeller 50,
Characterized in that the vibration sensor (300) is located at the front edge (11) of the rudder (70) behind at least one propeller (50) in the direction of movement of the ship (S1). 9. A method as claimed in claim 8, wherein the vibration sensor (300) comprises a front edge of the rudder (70) at a basic height position corresponding to the height of the tip of the blade of the at least one propeller (50) 71), while a vertical deviation (V1) of less than +/- 25% of the diameter (D1) of the propeller (50) is permitted from the basic height position. 10. A vessel arrangement as claimed in any one of claims 1 to 9, characterized in that the vessel is a tanker, car carrier, container vessel or ferry carrying a cruiser, oil or liquefied natural gas. 11. A device as defined in any one of claims 1 to 10, characterized in that the power of at least one propulsion unit (100) is at least 1 MW. As a method on a ship,
- a hull (200)
At least one propulsion unit (100) comprising at least one propeller (50) connected to a propulsion engine (30) via a propulsion engine (30), a transmission means (40) and a transmission means (40) At least one propulsion unit (100)
- a vibration sensor (300) located near at least one propeller (50) for sensing the vibration caused by the cavitation of at least one propeller (50)
The method of claim 1,
- measuring the cavitation of at least one propeller (50) through the vibration sensor (300)
- supplying an output signal of the vibration sensor (300) to the control unit (400)
- detecting the cavitation of at least one propeller (50) and analyzing the output signal of the vibration sensor (300) in the control unit (400) to determine if a worse degree of cavitation occurs,
- indicative of a worse degree of cavitation appearing on the display unit in the navigation bridge and / or adjusting the rotational speed and / or power of the propulsion engine (30) when a worse degree of cavitation appears, The adjustment step
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