KR101587478B1

KR101587478B1 - Heave motion damping device for marine floating body

Info

Publication number: KR101587478B1
Application number: KR1020140088563A
Authority: KR
Inventors: 김대호; 오영태
Original assignee: 대우조선해양 주식회사
Priority date: 2014-07-14
Filing date: 2014-07-14
Publication date: 2016-01-22

Abstract

The present invention is characterized in that an attachment 20 having a larger area of the bottom surface 22 than the upper surface 21 is provided on the outer circumferential surface of the offshore structure in a mechanism for damping the hib motion of the offshore structure.
Accordingly, in the semi-submersible submersible oil drilling rig, an additive for improving the hib motion is installed on the outer surface of the pontoon to prevent damage to equipment due to seawater flow.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a diving apparatus for a marine structure,

The present invention relates to a mechanism for reducing the heave motion of an offshore structure, and more particularly, to a heave motion damping mechanism of an offshore structure for preventing equipment damage due to seawater flow in a semi-submersible submarine oil rig.

Semi-submersible oil drilling rigs perform drilling operations in a suspended state at sea, and thus necessarily carry upward and downward heave movements due to the flow of seawater. The depression speed in the up and down direction by the hive motion not only degrades the performance of the drilling equipment but also reduces the durability and shortens the service life. For the pontoon shape, a device such as a heave plate or an additive is added to improve the motion of the hibbing motion.

Prior art documents referred to in this connection include Korean Patent Publication No. 2004-0018305 (Prior Art 1), Korean Patent Laid-Open Publication No. 2013-0113482 (Prior Art 2), and the like.

Prior Art 1 relates to a ship anchored at the seabed, the ship comprising at least two transverse skirts near the keel level along longitudinal side surfaces, the transverse skirts being such that the inherent roll period of the ship exceeds a predetermined period And in the case of a skirter-less vessel, the inherent roll period is less than the predetermined period.

Prior Art 2 is a hydraulically actuatable hydraulic actuator connected between a ship and a load suspended from the vessel and adapted to change the distance between the load and the vessel in response to a hive motion of the vessel, And a hydraulic actuator fluidly connected to the first hydraulic machine for operation by the first hydraulic machine. Thus, an effect of maintaining a substantially constant supporting force on the load suspended from the ship is expected.

However, the transverse skirt of the above-mentioned prior art document 1 has the same size as the top and bottom so that it is limited to the hybrid motion, and the prior document 2 is limited to the specific load to be loaded into the sea bed.

1. Korean Patent Publication No. 2004-0018305 entitled "Vessel including transverse skirt" (Date of Publication: March 3, 2004) 2. Korean Patent Laid-Open Publication No. 2013-0113482 entitled " Hibb Compensation System "(Open date: October 15, 2013)

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned problems of the prior art by providing a semi-submersible submersible oil drilling rig with an additive for improving the hib motion on the outer surface of the pontoon, And a hib motion damping mechanism of the structure.

In order to attain the above object, the present invention provides a mechanism for damping the hib motion of an offshore structure, wherein an adherent having a larger area on the bottom surface than the upper surface is provided on the outer circumferential surface of the offshore structure.

According to the detailed configuration of the present invention, the adduct is formed into a triangular, ladder-like or mixed form cross-sectional structure.

According to the detailed construction of the present invention, the top surface of the adduct has an area of 50% or less as compared with the bottom surface.

According to the first embodiment of the present invention, at least a part of the adduct is provided so as to be vertically displaceable via a displacement means having an elevator.

According to a second embodiment of the present invention, at least a part of the adduct is provided so as to be variable in size through a displacement means having a drive cylinder.

According to the detailed configuration of the present invention, the displacement means varies the position or the size of the ad- dress by the controller of the control means, and the controller utilizes the input of the vibration sensor and the position sensor.

As described above, according to the present invention, in the semi-submersible submersible oil drilling rig, there is an effect of preventing equipment damage due to seawater flow by installing advection enhancing the hib motion on the outer surface of the pontoon.

1 is a schematic view showing a state in which a damping mechanism according to the present invention is installed;
2 is a schematic view showing an installation state according to the first embodiment of the present invention;
3 is a schematic view showing an installation state according to a second embodiment of the present invention.
Fig. 4 is a graph showing the comparison between the conventional RAW and the present RAW

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is directed to a mechanism for damping the heave motion of an offshore structure, but is not necessarily limited to a semi-sub league. The offshore structures, such as semi-sub leagues, have a structure that is supported by the pontoons 10 via the columns 15 in the downward direction of the deck 12.

According to the present invention, an adherent 20 having a larger area of the bottom surface 22 than the upper surface 21 is provided on the outer peripheral surface of the offshore structure. The adduct 20 is installed so as to be securely exposed to the outer surface of the pontoon 10. [ The top surface 21 of the ocean structure is subjected to the upward resistance and the bottom surface 22 is subjected to the downward resistance. Therefore, the shape of the bottom surface 22 which receives the vertical reaction force is maintained, compared with the conventional pontoon 10, so that the performance of the hip motion can be improved.

According to the detailed configuration of the present invention, the adduct 20 is formed in a triangular, ladder or mixed form. In the case of a triangular cross section, the upper surface 21 is not formed or inclined. In the case of a ladder-shaped cross section, the upper surface 21 has a narrow upper surface 21, an inclined side surface and a wide bottom surface 22. The adduct 20 is formed over a certain length on the side of the pontoon 10, and a triangle and a ladder can be mixedly formed in the longitudinal direction.

According to the detailed configuration of the present invention, the upper surface 21 of the adhering substance 20 has an area of 50% or less as compared with the lower surface 22. In the case of a triangular section, the area ratio is close to 0%, and in the case of a ladder section, the area ratio may exceed 50%. As a result of performing the hybrid motion RAO simulation using a commercial program (DNV HydroD) of the related industry, if the upper surface 21 exceeds 50% of the bottom surface 22, the performance improvement of the hive motion is insufficient.

According to a first embodiment of the present invention (FIG. 2), at least some of the additions 20 are arranged so as to be vertically displaceable via a displacement means 30 having an elevator 34 . The drive means 30 of the first embodiment places the adduct 20 on the deck 12 side during the movement of the offshore structure or in other special circumstances. Therefore, it is possible to exclude the change (bad condition) of the navigation performance due to the linear change, thereby reducing the possibility of unintentional problems caused by using the adhering substance 20. [

In a specific embodiment, the rails 32 are provided at the pontoon 10, the column 15 and the deck 12 to support the adduct 20 so as to be movable up and down. The elevator (34) can take a winding method using a wire or a chain or a lead screw-worm gear method. In the former case, it is necessary to add a fixing member for fixing the adhering substance 20 in place, but in the latter case, the arbitrary positional change of the adhering substance 20 is restricted without the fixing member.

According to a second embodiment of the present invention (FIG. 3), at least some of the adducts 20 are provided so as to be variable in size via displacement means 30 having a drive cylinder 36. The driving means 30 of the second embodiment is not limited to the positional change of the adhering substance 20 but the size variation. In this case, the structure of the pontoon 10 is relatively complicated, but it eliminates the rail 32 and the like, which is advantageous in simplifying the overall structure.

In a specific embodiment, the adduct 20 is mounted horizontally on the pontoon 10 or is rotatably mounted via a hinge 38. In any case, linking the drive cylinder 36 with the interior of the adduct 20 causes a variation in size as the adduct 20 exits and exits the pontoon 10. [ Thereby reducing the possibility of an unfavorable problem such as a decrease in the operational performance due to the linear change by the additive 20.

On the other hand, in the first embodiment and the second embodiment, the adhering substance 20 can be partially installed without covering the entire length. That is, the variable equation of FIG. 2 or 3 is partially applied based on the fixed equation of FIG. In addition, the variable formulas of FIGS. 2 and 3 may be applied in combination. For example, Figure 2 applies to both ends of the column 15 and Figure 3 applies to the center.

According to the detailed configuration of the present invention, the displacement means 30 varies the position or the size of the adhering substance 20 by the controller 46 of the control means 40, and the controller 46 controls the vibration sensor 42, And an input of the position sensor 44 are utilized. The control means (40) automatically controls the position or size variation of the adduct (20) under the set condition. The vibration sensor 42 is installed on the deck 12 and generates various signals related to vibrations such as amplitude and acceleration. A plurality of position sensors 44 are provided on the path of the rail 32 in the case of the first embodiment and a plurality of them are provided on the pivot path of the adhering substance 20 in the pontoon 10 in the case of the second embodiment. The controller 46 installed on the deck 12 comprises a microprocessor, a memory, and a microcomputer circuit having an I / O interface.

The controller 46 inputs the change of the vibration sensor 42 corresponding to the marine climate condition in which the marine structure is disposed and changes the position or the size of the adduct 20 using the position sensor 44, Maintain motion.

Fig. 4 shows the hybrid motion RAO calculated using the commercial program (DNV HydroD). As a result of comparing the RAO between 10 seconds and 20 seconds in which most of the wave periods are distributed, it is determined that the present invention has a performance improvement of about 7% in the hib motion. It can be seen that the portion shown in red in FIG. 4 is lower than the portion shown in blue and is stable. This will contribute to the improvement of the efficiency of the drilling of the offshore structure without reducing the performance of the equipment or weakening the durability.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims. It is therefore intended that such variations and modifications fall within the scope of the appended claims.

10: pontoon 12: deck
15: Column 20: Adduct
21: upper surface 22: bottom surface
30: drive means 32: rail
34: elevator 36: drive cylinder
38: Hinge 40: Control means
42: Vibration sensor 44: Position sensor
46:

Claims

CLAIMS 1. A mechanism for damping the hive motion of an offshore structure, comprising:
(20) having a larger area of the bottom surface (22) than the upper surface (21) is provided on the outer peripheral surface of the offshore structure,
At least a portion of the adduct (20) may be displaced up and down through a displacement means (30) having an elevator (34)
At least a portion of the adduct (20) is installed on the outer circumferential surface of the offshore structure via displacement means (30) having a drive cylinder (36)
The displacement means 30 varies the position or size of the adduct 20 by means of the controller 46 of the control means 40 and the controller 46 is connected to a vibration sensor 42) and an input of a position sensor (44) for detecting the position or size of the addend (20).

The method according to claim 1,
Characterized in that the adduct (20) is formed in a cross-sectional structure of a triangular, ladder-like or mixed form of opaque light.

The method according to claim 1,
Characterized in that the top surface (21) of the adduct (20) has an area of 50% or less as compared to the bottom surface (22).

delete