Hydraulic and earth engineering – Subterranean or submarine pipe or cable laying – retrieving,... – Submerging – raising – or manipulating line of pipe or cable...
Reexamination Certificate
2001-06-05
2003-07-08
Lee, Jong-Suk James (Department: 3673)
Hydraulic and earth engineering
Subterranean or submarine pipe or cable laying, retrieving,...
Submerging, raising, or manipulating line of pipe or cable...
C405S154100, C405S166000, C405S167000, C405S168300, C405S170000, C414S022510, C414S022690, C414S745400, C414S745700
Reexamination Certificate
active
06588981
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Foreign priority benefits a e claimed under 35 U.S.C. §119 to United Kingdom Patent Applications, Serial No. GB 00135 69.9 filed Jun. 5, 2000 and Serial No. GB 0103861.1 filed Feb. 16, 2001, the entire disclosures of said applications are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The invention relates to pipe handling apparatus, and in particular to a clamp for holding and/or paying out under tension an elongate article, such as a steel or similar pipe line or cable in deep water, from the deck of a pipe laying vessel. The invention independently relates to a piston arrangement suitable for applying radial compressive forces on a pipe or other cyclidrincal member, for example in radial friction welding.
Various arrangements are known for pipe laying operations. For deep water applications, the “J-Lay” arrangement has been adopted, in which, a continuous steel pipe is launched into the water at a relatively steep angle, using a tiltable ramp or tower. Examples of such systems are known for example from U.S. Pat. No. 5,975,802 of the present applicant, and from WO-A-99/50582 and WO-A-99/35429. From these documents, it will be understood that a great weight of pipe has to be supported beneath the vessel to control the paying out of the pipeline. For this purpose, the known documents propose either track-type tensioners or travelling clamps to grip and control movement of the pipe. A number of methods are currently used to apply pressure to the friction surfaces of these clamps. To date these have been by direct pressure applied by screw jacks or hydraulic rams, levers, pressurised bladders, or cams. These solutions tend to be bulky and do not lend themselves to use on a J-lay ramp where the clamp must pass between work stations at each payout of the pipeline.
It is presently desired to work at ever-increasing sea depths, and each new project therefore demands greater and greater tensions to be handled by the apparatus on the ramp. In meeting this requirement, the ramp itself must become stronger and therefore heavier, and also the tensioner and/or clamp and lifting apparatus become heavier at the same time. Aside from weight and expense of the vessel becoming undesirably increased, this weight is located high above the waterline, and therefore creates stability problems in the design of the vessel as a whole.
WO-A-98/48142 discloses a rack-and-pinion lifting arrangement as part of a drilling rig derrick. In this arrangement the weight of equipment to be lifted is taken by an articulated rack made of a large number of segments, running in a vertical main guide rail. The rack is incompressible longitudinally, and is driven from below by motors, such that the centre of gravity of the arrangement is not unduly raised. Moreover, the guide rails and tower themselves do not take the vertical load, and the derrick can therefore be of lighter construction itself.
Our co-pending application filed the same day and claiming priority from UK applications GB 00135698.1 (63591GB) and GB 0103861.1 (63591GB2) proposes using a preferred novel form of clamp for pipelay operations. While the present invention, relating to support and drive arrangement for a travelling clamp will be illustrated using such clamps, the invention is not limited to any specific form of clamp.
The invention aims to provide an improved clamp for use in pipelay and other applications.
BRIEF SUMMARY OF THE INVENTION
In accordance with a first aspect of the invention there is provided pipe handling apparatus having an articulated rack, a travelling clamp and guide means for guiding the travelling clamp and rack within an elongate structure, wherein drive means for elevating and lowering said clamp under load are arranged to act at a lower portion of said rack, the travelling clamp being connected to be driven along said guide means by movement of said rack in the guide means.
In one example the pipe handling apparatus comprises an elongate structure which is tiltable about a pivot point.
The pipe handling apparatus may be adapted for use on a vessel for laying pipes wherein said pivot point is substantially at deck level of said vessel, and the remainder of the structure is tiltable about said pivot point above deck level. Further, the drive means may be located within said structure below said pivot point.
In one arrangement of the invention a number of racks may be applied for balanced driving of the travelling clamp. Further each of the travelling clamps may be driven by an independent rack or racks.
In this invention the articulated rack below the drive means may act as a secondary guide means to the main guide means.
The travelling clamp may be driven by one or more helically threaded gears extending the length of said elongate support structure.
In one example of the invention, a piston driving arrangement for use in pipe handling apparatus is provided, the piston driving arrangement including a piston member constrained to move along a first axis towards and away from a fixed support, wherein an hydraulically operated wedge member is driven transverse to the first axis so as to act between the piston member and said fixed support to effect said motion.
The wedge member may be keyed to said piston member so as to effect forcible movement of the piston in opposite directions along said first axis. In one example the keying comprises a dovetail channel and rail arrangement.
Further, the wedge member may be keyed to the fixed support, or otherwise constrained against movement of said support.
The wedge member of the piston driving arrangement may be connected to hydraulic means.
In one example a plurality of wedges are grouped by mechanical linkage to a common hydraulic actuator. The plurality of wedges in this example may be each driven individually.
Alternatively, the plurality of wedges may be grouped by hydraulic linkage to equalise actuating forces around the circumference of an object under pressure.
The piston arrangement may be part of a radial compression arrangement in which a plurality of such pistons have their first axes aligned radially. The piston driving arrangement of this type of configuration may be arranged so that it provides radial pressure in radial friction welding apparatus.
The piston driving arrangement may be part of a pipe clamp for use in pipe laying apparatus, for example, with the piston being the closing drive means of a pipe clamp for use in pipe laying apparatus.
Further, the invention provides a clamp, for example, one adapted for use in pipe handling apparatus, the clamp including a plurality of ram arrangements mounted on a support and directed radially toward the centre of a workpiece object to be gripped, each ram arrangement comprising a push rod constrained to move in a radial direction and a wedge member driven in a direction across the radial direction and having an inclined surface so as to act between the push rod and said support to effect motion in said radial direction.
The wedge member in one embodiment is driven by hydraulic power. In a compact embodiment, the inclined surface is formed within the body of a hydraulic piston. Actuating surfaces may be provided at each end of said piston, the whole being mounted in a hydraulic cylinder, the push rod projecting through a side wall of said cylinder.
The inclined surface may be keyed to said push rod, so that the push rod can be pull as well as pushed along said first axis by the movement of the wedge member. The force therefore applied to the workpiece, such as the pipe, is a positively transmitted force and the ram is also positively withdrawn from contact with the elongate member when desired.
The keying of the push rod and the wedge may be by means of complementary angled keyways. The wedge member may similarly be keyed to the fixed support, or otherwise constrained against movement of said support.
A further clamp may be provided and controlled to operate in a set pattern. For example two co-operating clamps may be provided and operated so that the clamp may trav
Turnbull Richard W
Willis Stewart K
Lee Jong-Suk (James)
Sheridan & Ross P.C.
Stolt Offshore Limited
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