GB2119837A

GB2119837A - Apparatus for the performance of maintenance work and/or repairs on an artificial work island

Info

Publication number: GB2119837A
Application number: GB08310111A
Authority: GB
Inventors: Horst Anthofer
Original assignee: Maschinenfabrik Scharf GmbH
Current assignee: Maschinenfabrik Scharf GmbH
Priority date: 1982-05-03
Filing date: 1983-04-14
Publication date: 1983-11-23
Also published as: DE3216374A1; GB8310111D0; JPS5927017A; DE3216374C2; GB2119837B; NO831277L; NL8301003A

Abstract

In artificial work island 1 difficulties are encountered in performing the necessary maintenance work or repairs, particularly on the lower side of the platform nearest to the water level. The unstable scaffolding structures hitherto proposed for this purpose have all proved unsatisfactory, being time-consuming and expensive makeshift solutions which in addition present a danger to the personnel entering such structures. The invention proposes a system in which at least to the lower side of the platform nearest to the water level a rail track 14 is secured in a looped configuration, a working stage 15 being automatically guided along the said track. By the aid of this working stage, which is preferably adjustable in length and pivotable, every zone of the lower side of the platform can now be approached and the required maintenance work and/or repair carried out. <IMAGE>

Description

SPECIFICATION Apparatus for the performance of maintenance work and/or repairs on an artificial work island This invention relates to an apparatus for the performance of maintenance work and/or repairs on the lower side of the platform of an artificial work island.

In this context the term "artificial work island" means, for example, a self-elevating platform pontoon capable of floating or travelling and used for the exploration of petroleum or gas deposits present under the sea-bed and also for the raising of the said raw materials. It may nevertheless also refer to an artificial work island of the kind which, particularly in areas close to the sea coast, is used for laying pipes, dredging for sand or the maintenance of shipping channels.

All these types of artificial work islands are usually provided with a subdivided platform immediately above the water, usually covering a considerable distance in the horizontal direction, the lower side of the platform being at least part of the time at a certain distance above the water level. While all other zones of the work island are accessible for maintenance and/or repair with comparative ease, it is extremely difficult to inspect the lower side of this platform close to the water, the said lower side being particularly exposed to wear and stress, and to carry out any repairs required. At regular intervals, for example, the lower side of the said platform has to be cleaned or re-painted. The pipes and other units of apparatus installed in this position also have to be checked and maintained.

Little attention has so far been devoted to the set of problems arising in connection with the lower sides of the platforms. On the contrary, the aforementioned maintenance and/or repair operations were unanimously accepted as a necessary evil. They were accordingly carried out with devices of a makeshift nature. These usually consisted of comparatively unstable scaffolding structures lowered over the outsides of the platform by means of cables and winches and then interconnected underneath the platform by means of planks and ropes. Operators working on stages of this kind are thus particularly accident-prone.

Their production, moreover, is disproportionately time-consuming and expensive, their design being more or less left to the skill of the maintenance or repair workers. In many cases, furthermore, these measures are taken by operators standing on vessels anchored underneath the platform and necessarily affected by the rise and fall of the sea.

It is, therefore, the object of the present invention to avoid these disadvantages and to provide an apparatus for the performance of maintenance and/or repairs on the lower side of a platform of an artificial work island which can reduce to a minimum the danger to which the personnel is subjected and also result in a noticeable reduction in the time and cost involved in the maintenance and repairs mentioned.

To attain this object the present invention provides an apparatus for the performance of maintenance work and/or repairs on the lower side of a platform of an artificial work island, possibly of the floating type, the said lower side being situated at least part of the time at a certain distance above the level of the water, comprising one or more rail tracks secured in a loop-shaped configuration to the lower side of the platform, and one or more working stages automatically guided along and suspended from the said rail tracks.

The rail track is installed in a fixed position underneath the platform, thus forming a fixed integral part of the latter. The working stage is automatically guided along the said rail track. This ensures a firm standing place for the personnel present on the working stage, not only when the latter is motionless but also when it is niioving. In the event of any rolling movements of the work island the working stage participates therein, so that the risk undergone by the personnel is limited to their particular place of work. All maintenance and repairs can be performed without difficulty, as the working stage, thanks to the looped configuration of the rail track, can be moved to any desired point on the lower side of the platform, so that no additional auxiliary stages or frameworks are required.Routine operations, such as the cleaning of the lower side of the platform or the application of a fresh coat of paint, can now be carried out continuously or whenever needed.

The installation of one single rail track in a fixed position is usually sufficient. Two or more rail tracks can nevertheless be provided, according to the construction of the platform, particularly the lower side thereof. Also, on the rail track or tracks more than only one working stage may be automatically guided. Fundamentally it is the measure to be adopted in the case in question that will determine the particular number of working stages required. In the vast majority of cases arising in practice one rail track and one working stage automatically guided thereon will be installed on the lower side of the platform nearest to the surface of the water. There is nevertheless no reason why further rail tracks with their respective working stages should not be provided on the lower side of other platforms likewise.

The rail track may be designed as desired.

However, it is of advantage for the rail track to be preferably made up of two rails adjacent and parallel to each other. This improves the automatic guiding of a working stage, thus increasing its stability from the point of view of operators standing thereon.

It is conceivable, within the scope of the invention, for the rail track to be preferably of the endless type. In such cases the working stage normally remains underneath the platform at all times.

It is, however advantageous to provide for that one or both of the two end sections of a rail track of the non-endless type can be coupled to a rerailing unit. This may be a special rail which can be coupled to and uncoupled from the rail track by means of automatic rapid-action connection devices. The working stage is then moved by means of the re-railing unit into an inoperative position when not in use or else transferred to the rail track of a different platform.

The invention renders the particular working position desired or required more easily accessible as a result of the fact that the working stage is preferably pivotable about a vertical shaft.

The pivoting range may amount to as much as a full circle.

The vertical shaft may be in the centre of the working stage. In view of the conditions underneath the platform, it is, however, more advantageous for the vertical shaft to be situated at one end of the working stage, which is of elongated construction. As this extends the radius of action of the working stage, the rail track can be made shorter and/or its looped configuration made wider. The vertical shaft may form a component part of a supporting column.

The aforementioned advantageous property of the invention is further improved by the fact that the working stage is adjustable in length. For this purpose it can be subdivided into two subassemblies displaceable in relation to each other.

The adjusting mechanism may be either mechanical or electrical. Pneumatically or hydraulically operable units are likewise possible.

To render the lower side of the platform still more accessible, particularly the units of apparatus and piping occupying that position, the invention also proposes that at least certain parts of the working stage should be adjustable in the vertical direction. This may apply, for example, to one free end section of the working stage. It is also possible, however, for the entire working stage to be constructed so as to be vertically displaceable in this manner. This purpose is preferably achieved by the use of hydraulically operable lifting cylinders. These lifting cylinders will then be situated, for preference, in a vertical plane which also intersects the pivot axis.

In an advantageous further development of the invention the working stage is self-propelling. This means that facilities are provided thereon to enable its occupants to steer it accurately to the place where it is required for use for the particular task to be performed.

The invention nevertheless also provides for the working stage to be advantageously equipped for remote control and fitted with a manual emergency operating device. The remote control system may prove of use, for example, in cases in which the working stage is to be conveyed to a certain point of the platform and the operators do not take up their positions on the working stage until then, gaining access thereto through flaps or hatches in the platform as well as a ladder usually provided on the working stage.By the aid of the manual emergency operating device, which enables the working stage to be moved longitudinally as well as pivoted, for example, it can always be moved, if the driving mechanism for one or both of these latter directions fails, to the positions where its crew can climb up onto the platform without difficulty, using the flaps or hatches provided in the said platform.

The working stage can be rendered selfpropelling in various different ways. One preferred method included in the scope of the invention is characterised by the fact that sections of pneumatic tubing which can be coupled to the working stage and form part of a compressed air supply unit are laid along the rail track. These may consist, in particular, of flexible pneumatic hoses.

They are of limited length and are each connected by one end to a fixed rotary connection. The rotary connections are incorporated into the compressed air supply system. When the working stage reaches the free end of one of these hoses the end portion of the hose which was up to that moment connected to the working stage is uncoupled and the end portion of the next section of hose connected up to the working stage in such a way as to convey the compressed medium.

The working stage can now once again move along the rail track over a length approximateiy equal to twice the length of the section of tubing until the free end of the next such section has been reached.

To prevent excessive sag in these sections of pneumatic tubing the invention provides that the working stage is preferably supplemented by a winch by which the sections of pneumatic tubing can be wound up or reeled off. This winch can be provided with a suitable coupling, such as an overrunning clutch. When the free end of a fresh section of pneumatic tubing is coupled to the working stage and the latter then continues on its way the section of pneumatic tubing will be wound up until the rotary connection is reached.

After the rotary connection has been passed the section of pneumatic tubing will then again unwind, possibly subject to a braking action.

In an alternative and equally suitable embodiment of a self-propelling working stage, the working stage is constructed to be coupled to a traction carriage having its own driving unit. The traction carriage is then preferably controlled from the working stage. An independent drive for the traction carriage may consist, in particular, of a Diesel engine. The Diesel engine is then able to supply, via a compressor unit carried thereon, the compressed air required for the operation of the working stage. The traction carriage is preferably suspended from two overhead trolleys, one of which is constructed as a chassis driving device, particularly with a friction wheel drive.

It is likewise of advantage for a pneumatically driven hydraulic unit for the provision of pressure fluid to be provided on the working stage. This hydraulic unit produces the pressure fluid required for satisfactorily operating the working stage, e.g.

for actuating the various hydraulic cylinders or motors. The pneumatic driving medium can then be supplied from outside via the flexible sections of pneumatic tubing or via the traction carriage.

It is also of advantage if plug connections for pneumatic tools are provided on the working stage. The operators are thus provided with the sources of power required for a wide variety of tasks to be carried out with the tools and auxiliary devices suitable in each case.

A preferred embodiment of the invention is one in which the vertical shaft of the working stage forms an integral part of a chassis automatically guided along the track rails. This provides a compact construction taking particular account of the conditions prevailing underneath a platform.

The chassis is then connected to the working stage by means of a supporting column.

In this connection it is also of advantage for the chassis consisting of a driving trolley and a supporting trolley to have one or more incorporated motors. The coupling of a driving trolley to a supporting trolley offers the advantage of creating a three-point supporting system enabling a working stage of ample length to be created, with a vertical pivot shaft provided at one end. The driving motor is preferably constructed as a hydrostatic radial-piston motor. It may nevertheless equally well consist of a hydrostatic axialpiston motor. Pneumatic or electric drives are likewise conceivable.

A further suitable method covered by the invention is to allow the driving motor to drive a friction wheel which is coupled via a hydraulic cylinder to a further friction wheel and which, by means of the said hydraulic cylinder and the further friction wheel, is pressed with a pincer-like action against one of the rails of the rail track.

Finally, according to a further characteristic of the invention, the free end of the working stage can be coupled, when it is travelling, to an overhead trolley. By this measure the load on the supporting system on the chassis can be relieved and the running stability of the working stage improved.

The invention will now be explained by way of example and with reference to the accompanying drawings in which: Figure 1 is a schematic side view of an artificial work island in the form of an ocean drilling rig; Figure 2 is a horizontal longitudinal section along the line Il-Il of Figure 1; Figure 3 is an elevational view, on a larger scale, of the detail marked Ill in Figure 1; Figure 4 is an end elevational view of the working stage of Figure 3 looking in the direction of arrow IV in Figure 3; Figure 5 is a plan view of Figure 4 looking in the direction of arrow V in Figure 4; Figure 6 is aside view of a further embodiment of a working stage; Figure 7 is an end elevational view of the working stage of Figure 6 looking in the direction of arrow VII, and Figure 8 is a plan view of the working stage of Figure 6.

Figure 1 shows a drilling rig 1, such as used for discovering petroleum or gas deposits and transporting the product to surface. The drilling rig 1 rests on a number of supports 2 and has two large continuous platforms 3 and 4 which are mounted a predetermined distance apart one above the other. The platforms 3 and 4 are inter connected by steps 5. A helicopter landing strip 6 is provided at one end of the upper platform 4. At the other end of the upper platform 4 are two platforms 7 and 8, extending over a small distance horizontally and surmounted by a derrick 9. The platforms 7 and 8 likewise are interconnected by steps 1 0. The platforms 3, 4, 7 and 8 have guard railings 11 all around their periphery.

To enable maintenance operations and/or repairs to be carried out on the lower side 12 of the platform 3 nearest to the surface of the water 13 (see also Figure 2) a rail track 14 of the non endless type is installed in a looped configuration on the said lower side 12 of the platform 3, a working stage 1 5 being suspended from the rail track 14 and automatically guided along it. It is self-evident that instead of one rail track and one working stage also more than one rail track and one working stage may be provided.

Figure 2 shows that the rail track 14 consists of two rails 1 6 extending parallel to each other and at a predetermined distance apart. The end portions 1 7 and 1 8 of the rail track 14 of the non endless type lead approximately into the middle of one longitudinal side 1 9 of the platform 3. With one end portion 1 7 is associated a re-railing unit 20 which can be automatically coupled to the end portion 1 7 of the rail track 'i 4. Needless to say, the lower sides of the platforms 4, 7 and 8 can likewise be provided with one or more rail tracks 14. The re-railing unit 20 then serves to transfer the working stages 1 5 from one platform to the other. This can be done with a hoisting apparatus not shown in the drawings.

One constructional version of the working stage 1 5 may be seen in greater detail in Figures 3 to 5. It mainly consists of a working platform 21 and a chassis 22 resting against one end of the working platform 21 and automatically guided along the rail track 14 consisting of rails 1 6 of the double-T type.

The working platform 21, provided with a railing 23 passing the whole way round and with an entrance 24, is adjustable in length. For this purpose the floor 25 of the working platform 21 and the side portions of the railing 23 are of telescopic construction over a certain limited length. The telescopically constructed portion 26 is retractable and extensible by means of one or more hydraulic cylinders 27 (Figure 3).

A pneumatically driven hydraulic unit 28, serving to provide pressure fluid for the various movements which the working stage 1 5 is required to perform, is mounted on the working platform 21. A section of pneumatic tubing 29 can be coupled to the hydraulic unit 28. This pneumatic tubing 29 consists of a number of sections in the form of hoses of limited length laid along the rail track 14 (see also Figure 2). Each section of pneumatic tubing 29 is connected to a rotary connection device 30 communicating in its turn with a compressed air supply unit 32 mounted on the platform 3.When the working stage 1 5 reaches one end 31 of a section of pneumatic tubing 29, the said section of pneumatic tubing 29 which up to that moment was coupled to the hydraulic unit 28 is uncoupled, so that the supply of compressed air is interrupted at the same time. The subsequent section of pneumatic tubing 29, as viewed in the direction of travel, is then coupled to the hydraulic unit 28, so that the working stage 15 is once again connected to the compressed air supply unit 32 on the platform 3. The working platform 21 may be equipped with a winch, not shown, which serves to wind up and reel off the sections of pneumatic tubing 29.

The working platform 21 is connected to the chassis 22 by means of a column 33 adjustable in length. This adjustment is effected by means of hydraulically operable cylinders, not show. The column 33 terminates in a ring mount 34 of the chassis 22. By the aid of a rotary motor 35 the working platform 21 can therefore be pivoted through an angle of up to 3600 about a vertical pivot shaft 36. One of the positions to which it can be pivoted is shown in broken lines in Figure 5.

The chassis 22 of the working stage 1 5 consists of a driving trolley 37 and a supporting trolley 38. Both trolleys 37 and 38 are fitted with running wheels 39 rotating about horizontal axes and supporting wheels 40 rotating about vertical axes. The driving system consists of a hydraulic motor 41 which drives a friction wheel 42 rotating about a vertical axis. The friction wheel 42 is coupled to a further friction wheel 44 (Figures 4 and 5) via a hydraulic cylinder 43 which presses the two friction wheels 42 and 44 against the web of the rail 1 6. The driving trolley 37 is connected to the supporting trolley 38 via a vertical shaft 45, so that curves can be negotiated (see Figure 5). For this purpose the driving trolley 37 is provided with an extending arm 46.

Figure 3 also shows that a hand crank 47, enabling the working stage 1 5 to be moved away by hand in case of emergency, can be mounted on the shaft of the driving friction wheel 42. A hand crank 47 of this kind can also be mounted on the shaft of the rotary motor 35.

A further embodiment of a working stage 48 is shown in Figures 6 to 8. In this case the working stage 48 is subdivided into a working platform 49 and a traction carriage 50. The traction carriage 50 has a Diesel engine 51 acting on a driving system 52 largely corresponding to the driving system shown in Figures 3 to 5. In other words, it includes two friction wheels 42 and 44, pressed against a rail 1 6 by means of the hydraulic cylinder 43. The system includes a spring brake 53 by which brake shoes 54 can be pressed against the rail 16. A rear chassis 55 of the traction carriage 50 is coupled to a chassis 57 of the working platform 49 via a coupling rod 56.

The working platform 49 is pivotable about a vertical pivot shaft 58, preferably through an angie of 900 in both directions. The shaft 58, forms part of a column 63 by which the working platform 49 is connected to the chassis 57. The final positions reached in the pivoting action are shown in dot-and-dash lines. The end portion 59 of the working platform 49 is movable vertically within limits in relation to the base 60. Hydraulic cylinders, not shown, may be employed for this purpose. In the course of travel the end portion 59 of the working platform 49 can be interlocked with a further trolley 61 connected to the front chassis 57 by a coupling rod 62.

Claims

1. Apparatus for the performance of maintenance work and/or repairs on the lower side of a platform of an artificial work island, possibly of the floating type, the said lower side being situated at least part of the time at a certain distance above the level of the water, comprising one or more rail tracks secured in a loop-shaped configuration to the lower side of the platform, and one or more working stages automatically guided along and suspended from the said rail tracks.

2. Apparatus in accordance with claim 1, wherein the rail track preferably comprises two rails adjacent and parallel to each other.

3. Apparatus in accordance with claims 1 or 2, wherein the rail track is of the endless type.

4. Apparatus in accordance with claims 1 or 2, wherein the rail track is of the non-endless type and has two end portions of which one or both are arranged to be coupled to a re-railing unit.

5. Apparatus in accordance with claim 1, wherein the working stage is pivotable about a vertical pivot shaft.

6. Apparatus in accordance with claim 5, wherein the vertical pivot shaft is positioned at one end of the working stage which is of elongated shape.

7. Apparatus in accordance with claims 1, 5 or 6, wherein the working stage is adjustable in length.

8. Apparatus in accordance with claim 1 or any one of claims 5 to 7, wherein at least certain parts of the working stage are adjustable in the vertical direction.

9. Apparatus in accordance with claim 1 or any one of claims 5 to 8, wherein the working stage is of the self-propelling type.

10. Apparatus in accordance with claim 1 or any one of claims 5 to 9, wherein the working stage is equipped for remote control and fitted with a manual emergency operating device.

11. Apparatus in accordance with any one of the preceding claims, wherein sections of pneumatic tubing which form part of a compressed air supply unit and which can be coupled to the working stage are laid along the rail track.

12. Apparatus in accordance with claim 11, wherein the working stage is supplemented by a winch with which the sections of pneumatic tubing can be wound up and unwound.

1 3. Apparatus in accordance with claim 9, wherein the working stage is constructed to be coupled to a traction carriage having its own driving unit.

14. Apparatus in accordance with claim 13, wherein the driving unit of the traction carriage is a Diesel engine.

15. Apparatus in accordance with claim 1 or any one of claims 5 to 14, wherein a pneumatically driven hydraulic unit for the provision of pressure fluid is mounted on the working stage.

1 6. Apparatus in accordance with claim 1 or any one of claims 5 to 15, wherein plug connections for pneumatic tools are provided on the working stage.

1 7. Apparatus in accordance with claims 5 to 16, wherein the vertical pivot shaft of the working stage forms an integral part of a chassis automatically guided along the rails of the track.

1 8. Apparatus in accordance with claim 17, wherein one or more driving motors are integrated into the chassis consisting of a driving trolley and a supporting trolley.

19. Apparatus in accordance with claim 18, wherein the driving motor drives a friction wheel which is coupled to a further friction wheel via a hydraulic cylinder and which together with the said further friction wheel is pressed against a rail of the track by the said hydraulic cylinder.

20. Apparatus in accordance with any one of the preceding claims, wherein the free end of the working stage is constructed to as to be able to be coupled to an overhead trolley in the course of travel.

21. Apparatus for the performance of maintenance work and/or repairs on an artificial work island, substantially as hereinbefore described with reference to and as shown in Figures 1 to 5.

22. Apparatus for the performance of maintenance work and/or repairs on an artificial work island, substantially as hereinbefore described with reference to and as shown in Figures 6 to 8.

23. Any novel feature or combination of features described herein.