Fixation System for Hydraulic Jacking System

Abstract

A self-elevating platform comprises a deck structure, a plurality of legs, a plurality of footings, and a jacking system, wherein the plurality of legs pass through the deck structure and are supported by the plurality of footings; and wherein the jacking system comprises a jackcase structure with a first locking pin, a jacking yoke with a second locking pin, a plurality of jacking cylinders with a first end and second end, where the first end of the jacking cylinders is supported by the jackcase structure, and the second end of the jacking cylinders by the jacking yoke; and a fixation system comprising a plurality of tension rods, wherein each tension rod has a first end and a second end, and wherein the first end of the tension rods is securely coupled with the jacking yoke, and the second end of the tension rods is securely coupled with the deck structure; thereby when the plurality of tension rods secures the jacking yoke to the deck structure, the load can be removed from the hydraulic cylinders and transferred to the fixation system.

Claims

1. A self-elevating platform comprising: a deck structure; a plurality of legs having a plurality of evenly spaced pin holes; a plurality of footings; and a plurality of jacking systems, wherein one jacking system is disposed with one leg; wherein the plurality of legs pass through the deck structure and are supported by the plurality of footings; and wherein the jacking system comprises: a jackcase structure with a first removable locking pin, wherein the jackcase structure is fixed onto the deck structure; a jacking yoke with a second removable locking pin; a plurality of jacking cylinders with a first end and second end, where the first end of the jacking cylinders is supported by the jackcase structure, and the second end of the jacking cylinders by the jacking yoke; wherein during retraction of a jacking process, the first removable locking pin is engaged with the jackcase structure so that load path is directly from the plurality of legs to the first removable locking pin and then to the jackcase structure; and wherein during pushing of the jacking process, the second removable locking pin is engaged with the jacking yoke so that the load path is from the plurality of legs, through the second removable locking pin, to the jacking yoke, through the plurality of jacking cylinders and then into the jackcase structure; and a fixation system comprising a plurality of tension rods, wherein each tension rod has a first end and a second end, and wherein the first end of the tension rods is capable of being securely coupled with the jacking yoke, and the second end of the tension rods is capable of being securely coupled with the deck structure; thereby when the jacking process is stopped and the second removable locking pin is still engaged with the jacking yoke, and the plurality of tension rods secures the jacking yoke to the deck structure, the load path is from the plurality of legs, through the second removable locking pin, to the jacking yoke, through the plurality of tension rods, and then into the deck structure.

2. The self-elevating platform of claim 1, wherein the first end of the tension rods is provided with a thread passing through an opening provided in the jacking yoke and secured using a first nut, and the second end of the tension rods is provided with a thread passing through an opening in the deck structure and secured using a second nut.

3. The self-elevating platform of claim 1, wherein the first end of the tension rods is provided with a thread passing through an opening provided in the jacking yoke and secured using a first nut, and the second end of the tension rods is permanently fixed to the deck structure.

4. The self-elevating platform of claim 1, wherein the first end of the tension rods is permanently fixed to the jacking yoke, and the second end of the tension rods is provided with a thread passing through an opening in the deck structure and secured using a second nut.

5. The self-elevating platform of claim 4, wherein the hydraulic cylinders are positioned to substantially align with the location of the tension rods.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Preferred embodiments according to the present invention will now be described with reference to the Figures, in which like reference numerals denote like elements.

[0017] FIG. 1 shows a block diagram of the basic arrangement of a self-elevating platform in the prior art.

[0018] FIG. 2 shows a block diagram of the basic arrangement of a hydraulic jacking system in the prior art.

[0019] FIG. 3 shows a block diagram of a hydraulic jacking system comprising a fixation system in accordance with one embodiment of the present invention.

[0020] FIG. 4 shows a block diagram of a hydraulic jacking system comprising a fixation system in accordance with another embodiment of the present invention.

[0021] FIG. 5 shows a block diagram of a hydraulic jacking system comprising a fixation system in accordance with yet another embodiment of the present invention.

[0022] FIG. 6 shows a block diagram of a hydraulic jacking system comprising a fixation system in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention may be understood more readily by reference to the following detailed description of certain embodiments of the invention.

[0024] Throughout this application, where publications are referenced, the disclosures of these publications are hereby incorporated by reference, in their entireties, into this application in order to more fully describe the state of art to which this invention pertains.

[0025] The present invention provides a fixation system for fixing the leg-deck structure connection for a self-elevating platform that utilizes a hydraulic jacking system. The fixation system comprises a plurality of adjustable tension rods that are so arranged to tie the jacking yoke to the deck in order to secure the yoke in position when the deck structure is elevated. In this way, a direct load path between the leg and deck structure is provided and the load can be released from the hydraulic cylinders in order for them to be maintained, or even removed for storage while the deck is elevated. This is desirable, particularly for cases where the platform is to remain at a single location for a period of several years.

[0026] Referring now to FIG. 3, there is provided a fixation system in accordance with one embodiment of the present invention. As shown in FIG. 3, the jacking system 40 is similar to that shown in FIG. 2 except for the inclusion of a fixation system. The fixation system comprises a plurality of tension rods 51 securing the jacking yoke 43 to the deck structure 10, where each tension rod 51 has a first end and a second end. The first end of the tension rods 51 is provided with a thread passing through an opening 52 provided in the jacking yoke 43 and secured using a first nut 53, and the second end of the tension rods 51 is provided with a thread passing through an opening 54 in the deck structure 10 and secured using a second nut 55. The tension rods 51 are provided with a sufficient length of thread such that various positions of the jacking yoke 43 can be accommodated. In general, the yoke position is allowed to vary by a distance at least equal to the distance between the lifting points 21, thus allowing adjustment to any final leg position.

[0027] The fixation system shown in FIG. 3 is able to be operated in the following way. During jacking operations, the tension rod 51, the first nut 53, and the second nut 55 can be removed and jacking can proceed as described in the description of FIG. 2. When the hull reaches its final elevation, with the second locking pin 44 engaged, the tension rod 51, the first nut 53, and the second nut 55 can be moved into the position shown in FIG. 3, for example by inserting the tension rod 51 through the decks structure 10 and the jacking yoke 43, and then securing the tension rod 51 in position using the first and second nuts 53, 55. Once the tension rods 51 and nuts 53, 55 are in position and sufficiently tightened to avoid slack, the load can be removed from the hydraulic cylinders 45 and transferred to the fixation system.

[0028] Referring now to FIG. 4, there is provided a fixation system in accordance with another embodiment of the present invention. The fixation system shown in FIG. 4 is similar to the fixation system shown in FIG. 3 except that the second end of the tension rods 51 is permanently fixed to the deck structure 10 for example by welding. In this embodiment, jacking is carried out with the tension rods 51 in position, but with the nuts 53 removed, or moved to a higher position on the thread whereby it does not interfere with the movement of the jacking yoke 43. This embodiment is convenient as it removes the need to lift the tension rods 51 into position and also removes the need to secure the second end of the tension rods 51 on location. The nut 53 can also be stored on the thread during jacking as long as it is moved to a location beyond the range of motion of the jacking yoke 43, which removes the need to lift the nut 53 into position.

[0029] Referring now to FIG. 5, there is provided a fixation system in accordance with yet another embodiment of the present invention. The fixation system shown in FIG. 5 is similar to the fixation system shown in FIG. 3 except that the first end of the tension rods 51 is permanently fixed to the jacking yoke 43 for example by welding. In this embodiment, jacking is carried out with the tension rods 51 in position, but with the nut 55 removed, or removed to a location on the thread whereby it does not come into contact with the deck structure 10 with the movement of the jacking yoke 43. This embodiment is convenient as it removes the need to lift the tension rods 51 into position and also removes the need to secure the first end of the tension rods 51 on location. The nut 55 can also be stored on the thread during jacking as long as it is moved to a location which avoids contact with the deck structure 10 taking into account the range of motion of the jacking yoke 43. This removes the need to lift the nut 55 into position. In contrast to the embodiment shown in FIG. 4, this embodiment enables the nut 55 to be mounted under the deck structure 10, where it can be better protected from the environment.

[0030] Referring now to FIG. 6, there is provided a fixation system in accordance with another embodiment of the present invention. The fixation system shown in FIG. 6 is similar to the fixation system shown in FIG. 5 except that the hydraulic cylinders 45 are repositioned to substantially align with the location of the tension rods 51. In this embodiment, the first end of the tension rods 51 is permanently fixed to the jacking yoke 43 for example by welding. In this embodiment, jacking is carried out with the tension rods 51 in position, but the nut 55 removed, or removed to a location on the thread whereby it does not come into contact with the deck structure 10 with the movement of the jacking yoke 43. As in the case of the fixation system shown in FIG. 5, this embodiment is convenient as it removes the need to lift the tension rods into position and also removes the need to secure the first end of the tension rods 51 on location. The nuts 55 can also be stored on the thread during jacking as long as it is moved to a location which avoids contact with the deck structure 10 taking into account the range of motion of the jacking yoke 43. This removes the need to lift the nut 55 into position. In addition, the alignment of the hydraulic cylinders 45 and tension rods 51 enable more efficient design of the jacking yoke structure as the lifting and fixation locations can be arranged more favorably. It also allows for a more compact design as the hydraulic cylinders 45 and tension rods 51 occupy the same horizontal space on the yoke 43, removing the need for these to be spread out. This allows the system to be used on smaller diameter legs, and allows a greater number of lifting points to be accommodated if required.

[0031] There is a large range over which the present invention could be used; the parameters will vary however depending on the type of platform, water depth, etc. The following exemplary parameters are provided for the sole purpose of illustrating the application of the present invention.

[0032] Leg diameterpreferably to be 1.5 m to 5 m, with common size of about 3.5 m.

[0033] Hydraulic cylinderspreferably to have lifting capacity of 200 to 800 metric tonnes (MT), with common capacity of about 500 MT.

[0034] Pin hole diameterpreferably range of 200 mm to 600 mm, with common size of about 350 mm.

[0035] Pin hole spacingpreferably to be 0.6 m to 2.5 m, with common size of about 1.5 m.

[0036] Jacking yokewill be sized according to leg diameter and the load required.

[0037] Tension rodspreferably to be steel bars, with diameter of 60 mm to 250 mm.

[0038] Length of tension rods will be based on, pin hole spacing and the dimension of the yoke and main deck structures to make sure it is long enough.

[0039] While preferred embodiments of the present subject matter have been described, it is to be understood that the embodiments described are illustrative only and that the scope of the invention is to be defined solely by the appended claims when accorded a full range of equivalence, many variations and modifications naturally occurring to those of skill in the art from a perusal hereof.