Semi-submersible type crane

Abstract

To provide a semi-submersible type crane for assembling a floating type offshore wind power generation facility on the sea, especially a semi-submersible type crane capable of stably working while suppressing its oscillation when lifting heavy objects.SOLUTION: A semi-submersible type crane 1 comprises a crane 3 on a deck surface of a semi-submersible type floating body 6 configured to include multiple columns 10 as a floating body, and a connecting member 11 that connects these columns 10 to each other. The semi-submersible type crane installs a mobile counterweight device 4 on the deck surface of the semi-submersible type crane. The mobile counterweight device 4 can be moved in any direction by installing a travel part on the bottom surface of a weight 18, provides winches 19A-19D on four corners, connects wire ropes 20a-20d paid out from the winches 19A-19D to the weight 18, and controls the movement of the weight 18 to a prescribed position by operating the winches 19A-19D.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a semi-submersible crane used to assemble floating offshore wind power generation facilities offshore, and more particularly to a semi-submersible crane that suppresses shaking and achieves stabilization when suspending heavy loads. [Background technology]

[0002] Traditionally, hydroelectric, thermal and nuclear power generation have been the main power generation methods used, but in recent years, wind power generation, which uses natural wind to generate electricity, has been attracting attention from the perspective of the environment and the effective use of natural energy. Wind power generation facilities can be installed on land or on water (mainly offshore), but in Japan, which has mountainous terrain behind its coasts, there are few plains in coastal areas where stable winds can be expected. On the other hand, Japan is surrounded by sea on all sides, and has the advantage that winds suitable for generating electricity can be easily obtained on the sea and there are fewer restrictions on installation. For this reason, many different types of offshore wind power generation facilities and floating structures have been proposed in recent years.

[0003] The floating structure can be broadly classified into a barge type float, which floats on the water surface, a semi-submersible type, in which the lower part of the float is submerged below the water surface to float in a semi-submerged state, and a spar type, which floats in an upright position like a fishing float.

[0004] With regard to the spar-type float, the applicant has proposed in Patent Document 1 listed below an offshore wind power generation facility consisting of a float, mooring lines, a tower, and a nacelle and multiple wind turbine blades installed at the top of the tower, wherein the float is an offshore wind power generation facility with a spar-type floating structure consisting of a lower concrete floating structure part (hereinafter referred to as the concrete floating structure part) in which concrete precast cylindrical bodies are stacked vertically in multiple tiers and each precast cylindrical body is fastened and integrated with PC steel members, and an upper steel floating structure part (hereinafter referred to as the steel floating structure part) connected to the upper side of this lower concrete floating structure part (hereinafter referred to as the steel floating structure part).

[0005] In the method of constructing the float of the spar-type offshore wind power generation facility, as shown in Fig. 8, the steel floating part is divided into steel rings of a predetermined weight at a shipyard, and then these steel rings are connected by welding to complete the steel floating part. Then, the steel floating part is loaded onto a barge and transported to the on-site fabrication yard, where it is unloaded (landed) at a quay using a large crane ship of 1300t class. Meanwhile, the concrete floating part is manufactured in a concrete manufacturer's factory in a state where each ring is divided into several parts in the circumferential direction for the convenience of truck transportation, and these divided rings are transported by truck to the on-site fabrication yard, where they are connected in the circumferential direction, and then each ring is connected in the longitudinal direction using PC steel to complete the concrete floating part. Finally, the steel floating part and the concrete floating part are connected using a large crane ship of 1300t class to complete the float. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5274329 [Patent Document 2] JP 2012-201219 A Summary of the Invention [Problem to be solved by the invention]

[0007] When constructing a floating offshore wind power generation facility on the ocean, it is desirable to install the wind turbine equipment such as the tower, nacelle, and blades while the spar-type float is floating on the ocean in a bay with calm waves. However, while the draft (part below the water surface) of the spar-type float is deep, at approximately 70 m or more, the water depth in a bay is generally shallower than this, making construction in the bay difficult. As such, the installation of the wind turbine equipment has traditionally been carried out outside the bay where the water is deep, using a large crane ship 70, as shown in Figure 9 (see Patent Document 2).

[0008] However, at present, there are only a few large crane ships in Japan that are capable of constructing offshore wind power generation facilities, and the daily usage fee (charter fee) is expensive, which poses the problem of huge charter costs.In response to this, in recent years, semi-submersible cranes equipped with cranes on semi-submersible floats have been manufactured for the construction of offshore wind power generation facilities, but since semi-submersible floats have a lighter weight than large crane ships, they are more susceptible to the effects of waves and lack stability, and when heavy objects such as towers and nacelles are hoisted, the entire float will shake and become unstable, which can cause problems during the assembly work of the wind power generation facilities.

[0009] Therefore, the main object of the present invention is to provide a semi-submersible crane for assembling floating offshore wind power generation equipment offshore, and in particular to provide a semi-submersible crane that is capable of performing work stably by suppressing swaying when hanging heavy objects. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention according to claim 1 provides a semi-submersible crane equipped with a crane on the deck surface of a semi-submersible float including a plurality of columns serving as buoyant bodies and connecting members connecting these columns to each other, A semi-submersible crane is provided, characterized in that a movable counterweight device is installed on the deck surface of the semi-submersible crane.

[0011] In the invention described in claim 1, a semi-submersible crane is structured with a mobile counterweight device installed on the deck surface. Therefore, when lifting heavy objects such as towers and nacelles with a crane, the weight of the mobile counterweight device can be moved to a position where the rocking caused by the lifting load can be suppressed, thereby suppressing the rocking of the hull and stabilizing it.

[0012] As the present invention related to claim 2, there is provided a semi-submersible crane as described in claim 1, in which the mobile counterweight device is made movable in any direction by providing a running part on the underside of the weight, a winch is placed at the four or three corners, or at the front and rear of the weight, a wire is paid out from the winch and connected to the weight, and the weight is moved and controlled to a predetermined position by operating the winch.

[0013] The invention described in claim 2 specifically defines the structure of a mobile counterweight device. Specifically, a suitable example is a device in which a running part is provided on the underside of the weight to allow it to move in any direction, a winch is placed in an appropriate position, and the weight is controlled to move to a specified position by operating the winch.

[0014] The present invention according to claim 3 provides a semi-submersible crane as described in claim 1, further comprising a tower fixing device provided on one side of the deck surface for integrally holding the tower of an offshore wind power generation facility.

[0015] The invention described in claim 3 above is a system in which a tower fixing device is provided on the semi-submersible crane to ensure that the displacement behavior is the same, since if the semi-submersible crane and the tower of the offshore wind power generation equipment displace differently when attaching wind turbine components such as the nacelle and blades to the top of the tower, installation becomes difficult.

[0016] As the present invention related to claim 4, there is provided a semi-submersible crane as described in claim 1, in which the deck on which the movable counterweight device is provided is structured such that the deck is placed on the upper surface of a frame structure arranged in a cantilevered manner on the opposite side to the side on which the crane of the semi-submersible float is arranged.

[0017] The invention described in claim 4 above specifies a deck structure that serves as a table on which a mobile counterweight device is installed. Specifically, it is preferable to have a structure in which a deck is placed on the top surface of a frame structure that is cantilevered on the side opposite to the side where the crane is installed.

[0018] According to a fifth aspect of the present invention, there is provided a semi-submersible crane as described in the first aspect, wherein the submersible portion of the semi-submersible floating body is provided with a plurality of fin stabilizers.

[0019] The invention described in claim 5 above provides a fin stabilizer in the submerged portion of the semi-submersible float to stabilize the hull against waves. Effect of the Invention

[0020] As described above in detail, the present invention relates to a semi-submersible crane for assembling floating offshore wind power generation facilities offshore, which makes it possible to carry out work stably by suppressing rocking, particularly when hanging heavy objects. [Brief description of the drawings]

[0021] [Figure 1] 1 shows a semi-submersible crane 1 according to the present invention, in which (A) is a side view and (B) is a plan view thereof. [Diagram 2] FIG. 2 is a plan view showing another example of the movable counterweight device 4. [Diagram 3] FIG. 2 is a plan view showing yet another example of the movable counterweight device 4. [Figure 4] This is a construction procedure diagram (part 1) of an offshore wind power generation facility using this semi-submersible crane 1. [Diagram 5] This is a construction procedure diagram (part 2) for an offshore wind power generation facility using a semi-submersible crane 1. [Figure 6] This is a construction procedure diagram (part 3) for an offshore wind power generation facility using a semi-submersible crane 1. [Figure 7] This is a construction procedure diagram (part 4) for an offshore wind power generation facility using a semi-submersible crane 1. [Figure 8] FIG. 1 is a flow diagram showing a floating body construction method for a spar-type offshore wind power generation facility. [Figure 9] FIG. 1 is a diagram showing the procedure for the integrated construction of the tower, nacelle and blades using a large crane ship 70. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0023] [Semi-submersible crane 1] A semi-submersible crane 1 according to the present invention will be described in detail with reference to Figs.

[0024] As shown in Figure 1, the semi-submersible crane 1 is equipped with a crane 3 on the deck surface of a semi-submersible floating body 2 which is composed of a number of columns 10, 10... which serve as buoyant bodies and connecting members 11, 11... which connect these columns.

[0025] The semi-submersible float 2 comprises the multiple columns 10, 10... which serve as buoyant bodies, three in the illustrated example. These columns 10 are cylindrical hollow structures, and the float base 6 of the semi-submersible float 2 is formed by arranging these columns 10, 10... at the vertices of a polygon in a plan view, for example, and then connecting these columns 10, 10... with connecting members 11, 11....

[0026] A deck body 7 is provided on the upper surface of the floating base 6, and a protruding deck section 8 is provided in a cantilever shape on one end side of the deck body 7. A deck section 9 for a movable counterweight is provided on the opposite side of the protruding deck section 8, straddling the deck body 7. A frame structure 12 is arranged in a cantilever shape on the underside of the protruding deck section 8 to provide structural reinforcement. Similarly, frame structures 13 and 14 are arranged in a cantilever shape on the underside of the deck of the deck section 9 for the movable counterweight to provide structural reinforcement. The deck body 7 is gradually narrowed in width toward the left side of the drawing, and the protruding deck section 8 is provided continuously from the narrowest end of the deck body 7, and is gradually narrowed in width toward the tip side, which is the bow side. The overhanging deck section 8 is a space provided as a facility for constructing offshore wind power generation facilities, and the movable counterweight deck section 9 is a space provided to ensure a range of movement for the weight, and is located on the stern side. Note that the deck main body 7 and the movable counterweight deck section 9 have a step structure due to the deck overlap, but they may be on the same level.

[0027] The crane 3 is provided on the upper surface of the deck main body 7 of the semi-submersible floating body 6, near the overhanging deck section 8. The crane 3 is installed directly above the column 11, so that the load from the crane 3 is directly transmitted to the column 11. A fixed type is preferable as the crane 3, but a mobile crane can also be mounted on the deck main body 7 in some cases. In any case, it is necessary for the crane to have the lifting capacity and lifting height to be able to erect the tower, nacelle, and blades of the offshore wind power generation facility. Furthermore, if a tower crane is used, the self-elevating structure makes it easy to ensure the desired lifting height.

[0028] A tower fixing device 5 for fixing the tower of the offshore wind power generation facility integrally with the semi-submersible crane 1 is provided on one side of the overhanging deck section 8. The tower fixing device 5 is U-shaped in plan view in the illustrated example, and each side is composed of trussed face members 15, and is supported upright by support members 17. A gripping device 16 capable of gripping the tower is provided inside the U-shaped structure formed by the face members 15. The tip arm of this gripping device 16 is freely openable and closable, so that the tower inserted inside can be firmly gripped. Although a large-scale tower fixing device 5 is shown in the illustrated example, it is also possible to use a single gripper device provided on the side of the overhanging deck section 8 as the tower fixing device 5 for simplicity.

[0029] A mobile counterweight device 4 is provided on the upper surface of the deck 9 for the mobile counterweight. As shown in FIG. 1(B), the mobile counterweight device 4 is configured to be movable in any direction by providing a running part on the underside of the weight 18, and has winches 19A-19D at the four corners, with wires 20a-20d unwound from the winches 19A-19D connected to the corners of the weight 18, and the weight 18 is controlled to move to a predetermined position by operating the winches 19A-19D. In the mobile counterweight device 4, the weight 18 can be moved to any position within the X and Y planes in a plan view. It is preferable to control the winches 19A-19D by coordinated control using a computer (not shown).

[0030] As shown in the figure, the weight 18 has a box-shaped structure and the weight can be adjusted by putting ballast material such as slag aggregate inside, or by putting in a combination of steel material or the like if the weight is insufficient.

[0031] As shown in Fig. 2, the winches 19A to 19C may be disposed at three corners of the apex of a substantially equilateral triangle, and the wires 20a to 20c that are paid out from the winches 19A to 19C may be connected to the weight 18, respectively, and the weight 18 may be moved and controlled to a predetermined position by operating the winches 19A to 19C. Alternatively, as shown in Fig. 3, the winches 19A and 19B may be disposed at the front and rear parts straddling the weight 18, and the wires 20a and 20b that are paid out from the winches 19A and 19B may be connected to the weight 18, and the weight 18 may be moved and controlled to a predetermined position in the Y direction by operating the winches 19A and 19B. In this case, it is preferable to provide movement guides 21 and 21 on both sides of the weight 18 so that the weight 18 can only move in the Y direction.

[0032] It is desirable to provide fin stabilizers 22, 22 in the submersible portion of the semi-submersible float 6, as shown in FIG. 1, to enhance stability against waves.

[0033] [Construction method for spar-type offshore wind power generation facility 1] Next, a method for constructing a spar-type offshore wind power generation facility using the semi-submersible crane 1 will be described in detail with reference to Figs.

[0034] As shown in FIG. 4, a float 25 of the spar-type offshore wind power generation facility is floated vertically on the sea, and temporary mooring ropes 26, 26 are connected to the float 25 to stabilize it.

[0035] The tower 27 assembled at a wharf yard or the like is transported to the construction site of the spar-type offshore wind power generation facility while being held by the tower fixing device 5 of the semisubmersible crane 1. At this time, in order to horizontally stabilize the hull that has been rocked forward by the lifting load of the tower 27, the weight 18 of the mobile counterweight device 4 is moved rearward.

[0036] Next, as shown in FIG. 5, temporary mooring ropes 28, 28 . . . are attached to the semi-submersible crane 1 to stabilize it, and then the tower 27 is connected to the upper part of the floating body 25.

[0037] Next, as shown in Fig. 6, the nacelle 29, which is a heavy load, is suspended by the crane 3 and mounted on the top of the tower 27. At this time, the weight 18 of the movable counterweight device 4 is moved further rearward according to the weight of the nacelle 29 to ensure stability.

[0038] Next, as shown in FIG. 7, the blades 30 are attached. In this case, since the suspended weight is lighter than that of the nacelle 29, the weight 18 of the movable counterweight device 4 is moved forward to ensure the stability (horizontal) of the hull.

[0039] In the above manner, the tower 27, the nacelle 29, the blades 30, 30 . . . are attached in this order to complete the spar-type offshore wind power generation facility. [Explanation of symbols]

[0040] Reference Signs List 1...semi-submersible crane, 2...semi-submersible float, 3...crane, 4...mobile counterweight device, 5...tower fixing device, 6...float base, 7...deck main body, 8...extending deck section, 9...deck section for mobile counterweight, 10...column, 11...connecting material, 12-14...frame structure, 16...gripping device, 18...weight, 19A-19D...winch, 20a-20d...wire, 25...spar-type float, 27...tower, 29...nacelle, 30...blade

Claims

1. A semi-submersible crane is provided on the deck surface of a semi-submersible float including a plurality of columns serving as buoyant bodies and connecting members connecting the columns to each other, A semi-submersible crane characterized in that a movable counterweight device is installed on the deck surface of the semi-submersible crane.

2. A semi-submersible crane as described in claim 1, wherein the movable counterweight device is capable of moving in any direction by providing a running part on the underside of the weight, a winch is arranged at the four or three corners, or at the front and rear of the weight, a wire is paid out from the winch and connected to the weight, and the weight is moved and controlled to a predetermined position by operating the winch.

3. 2. A semi-submersible crane according to claim 1, further comprising a tower fixing device provided on one side of the deck surface for integrally holding the tower of an offshore wind power generation facility.

4. A semi-submersible crane as described in claim 1, wherein the deck on which the movable counterweight device is provided is constructed such that the deck is disposed on the upper surface of a frame structure provided in a cantilevered manner on the opposite side to the side on which the crane of the semi-submersible float is disposed.

5. 2. A semi-submersible crane according to claim 1, further comprising a plurality of fin stabilizers in the submersible portion of the semi-submersible float.

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