JPH02283590A - Tendon connecting device for tension leg platform - Google Patents

Abstract

PURPOSE:To facilitate the connecting and removing work of a tendon as well as the adjustment of its length by holding the upper end of an integrally welded type tendon, connected by a flexible joint, at the upper part in a column by means of a rocking collar. CONSTITUTION:The upper end connection part of tendon is connected to the lower end of a tendon shroud 25 by a flexible joint 24, and the lower end of the tendon shroud 25 is fitted at the bottom part 2B of the column 2 of a tension leg platform(TLP) 21 through a tension sleeve 23. The upper end of the tendon 25 in the column is held within a mooring chamber 26 located at the upper part in the column by a rocking collar 27, thus enabling minute adjustment at the time of installing the tendon 8 between the TLP 21 and a template. The economical tendon formed into an integrally welded type can be thus obtained so as to facilitate the connecting and removing work of the tendon between the TLP and template.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a system in which a tendon integrally welded to a required length on the coast is towed to the installation sea area, and installed and removed as a mooring line for a tension leg platform. The present invention relates to a tendon connection device for a tension leg platform that allows easy connection of tension legs.

[Conventional technology]

Conventionally, for example, tension leg platforms (hereinafter referred to as TLPs) are installed at deep water depths of 500 m to 1000 m.
), as shown in Figure 5(A),
For example, a large number of steel pipe-shaped tendon elements 1 with a length of about 10 m are stored in the mooring chamber 3 at the top of the column 2,
In the sea area where the TLP is installed, these tendon elements 1 are connected one by one with screws 4 and suspended from the column 2 to the bottom of the water, as shown in Figure 5 (B), and a template is installed as a foundation on the seabed. In this case, a method of connecting using an anchor connector 5 or the like is adopted.

However, in the above method, the mechanism of the screw 4 that connects the tendon element 1 is a forged product, and the tendon element 1 becomes very expensive.

Another problem is that the number of devices installed in the mooring room 3, such as tendon connection devices, increases.

In particular, in the case of deep water, the storage space for the tendon element 1 becomes large, which is disadvantageous in terms of arrangement, and furthermore, there are problems in that it takes a long time to install the tendon, and furthermore, the work efficiency is poor.

Therefore, as a countermeasure for the above, as shown in Fig. 6 (A), column 2 of TLP on the water surface and template 7 on the seabed B.
A tendon 8 to be connected to the TLP pontoon is integrally formed by welding to the required length in a ground space such as on the coast, and is towed to the installation location. A system in which the connection is made via a flexible joint 10 at the bottom has been proposed.

In this method, instead of the screw 4 of the tendon element l shown in Fig. 5(B), the integral steel pipe type tendon 8 is connected by welding, so the product unit price is low and it is close to the installation sea area. Since the tendon 8 of the required length completed on the coast is attached to the installation area by attaching a floating body and towing it, the installation period is shortened and it is more economical than the TLP method shown in Fig. 5 (A). be.

However, even in this method, it is difficult to connect the column 2 and the tendon 8 because the connection position between the column 2 and the tendon 8 is underwater, and it is difficult to remove the tendon 8 for inspection, maintenance, and repair of the system during operation. In addition, there is a problem that the length of the tendons 8 cannot be adjusted when the template 7 sinks unevenly.

In addition, the flexible joint 10 shown in FIG. 5(C)
Since the elastomer 12, which is a laminated material of rubber and steel plates, is used, the tilt angle of the tendon 8 is 18.5 at maximum.
When connecting a long welded integral tendon 8 to the bottom 2B of the column 2, the lower end of the tendon 8 comes into contact with the seabed B, making the connection work difficult.

In addition, in FIG. 6(B), the lower end of the tendon 8 is connected to the template 7 on the seabed B by a flex joint 40.

[Problem to be solved by the invention]

The present invention has been made in order to solve the problems of the conventional art, and while adopting an economically advantageous welded-type tendon, the tendon connection work, removal work, and tendon length adjustment are facilitated. The object of the present invention is to provide a tendon connection device for a tension leg platform that can be used to connect tension legs.

[Means to solve the problem]

As a means for solving the above-mentioned problems, the tension leg plant form tendon connection device of the present invention flexibly connects the upper end of the tendon, which is integrally welded to the required length, to the column bottom via a tendon sleeve. It is constructed by holding the upper end of the in-column tendon connected to its lower end with a joint at the upper part of the column with a locking collar, and this in-column tendon allows the welded integral tendon to be easily pulled up into the column and connected. or can be removed.

〔Example〕

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

FIG. 1 is a sectional view of a main part of a tendon connection device according to the present invention,
2(A) is an enlarged side sectional view of the upper end connection part of the tendon in FIG. 1, FIG. 2(B) is a sectional view taken along line AA in FIG. 2(A), and FIG. BB sectional view of Figure (A), Figure 3 (A
) is a side cross-sectional view of the lower end connection part of the tendon in Figure 1, Figure 3 (B) is a cross-sectional view taken along line C-C in Figure 3 (A), and Figure 4 (A) is the installation of the tendon in Figure 1. FIG. 4(B) is an explanatory diagram of the state at the start of work, and is an explanatory diagram of the state in which the tendons are held in position directly below the tendon shroud and lifted up.

First, this tendon connection device connects a large number of steel pipes by welding on land such as the coast, and the floating body is attached to a welded integrated tendon 8 formed to the required length as shown in Fig. 4 (A).
), after the tugboat 20 tows the TLP 21 to the set position, the pull line 22 is used to pull the TLP 2
1 and a template 7 provided on the seabed B at their upper and lower ends, respectively.

Therefore, at the upper end connection part of the tendon 8, as shown in FIG.
), FIG. 2(B), and FIG. 2(C), it is connected to the lower end of the tendon shroud 25 by a flexible joint 24 of the universal joint type, and the lower end of the tendon shroud 25 is connected to the lower end of the tendon shroud 25. As shown in Figure 1, T
It is attached to the bottom part 2B of the column 2 of the LP21 via the tension sleeve 23, and since this flexible joint 24 is used, the tilt angle of the tendon 8 is allowed up to 90'', and as a result, as shown in FIG. As shown in B), when the in-column tendon 25 is pulled up into the column 2, the tendon 8 connected to its lower end via the flexible joint 24 can be bent up to 90''.

The upper end of the column tendon 25 is held by a locking collar 27 in a mooring chamber 26 at the upper part of the column 2, as shown in FIG.
When installed between the template 1 and the template 7, fine adjustment is possible.

In the mooring chamber 26 shown in FIG. 1, a load cell 31 is provided at the bottom of the locking collar 27 via a seal 28, and at the top thereof, a
) is provided with a winch 29 of a tendon lifting line 30.

In addition, the lower end of the tendon 8 is shown in FIG.
As shown in Figure (B), it is also connected to the template 7, which is the foundation on the seabed, by a flexible joint 32 of the universal joint type so that an inclination angle of up to 90'' is allowed.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to employ an economical tendon that is integrally welded in advance to a required length, and the work of connecting and removing the tendon between the TLP and the template is required. This has the effect of providing an economical tendon connection device.

In particular, the tendon connecting device of the present invention has the advantage that the length of the tendon can be easily adjusted by finely adjusting the tendon installation at the upper end of the tendon in the column when the template is unevenly settled.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a tendon connection device according to the present invention,
2(A) is an enlarged side sectional view of the upper end connection part of the tendon in FIG. 1, FIG. 2(B) is a sectional view taken along line AA in FIG. 2(A), and FIG. BB sectional view of Figure (A), Figure 3 (A
) is a side cross-sectional view of the lower end connection part of the tendon in Figure 1, Figure 3 (B) is a cross-sectional view taken along line C-C in Figure 3 (A), and Figure 4 (A) is the installation of the tendon in Figure 1. Figure 4 (B) is an explanatory diagram of the state at the start of work, and Figure 5 (A) is an explanatory diagram of the state in which the tendons are held in position directly below the tendon shroud and lifted up.
) is a perspective view of the mooring chamber of the conventional TLP, FIG. 5(B) is a side view showing the connection state of the tendons in FIG. 5(A), and FIG. 5(C) is the flexible mooring chamber in FIG. 5(B). Figure 6 (A) is an enlarged perspective view of the joint, Figure 6 (A) is a perspective view of TLP using a conventional welded integrated tendon, Figure 6 (B) is Figure 6 (A).
FIG. 3 is an enlarged side sectional view of the main part of the connection part at the upper end of the tendon. 2...Column, 2B...Bottom, 8...Tendon,
21...TLP, 23...Tendon Sleep, 2
4... Flexible joint, 25... Tendon in column, 27... Locking collar

Claims (1)

[Claims] The upper end of the tendon, which is integrally welded to the required length, is connected to the lower end of the column by a flexible joint via a tendon sleeve, and the upper end of the tendon in the column is held at the upper part of the column by a locking collar. Platform tendon connection device.