DE3240777C2 - Body made of cast steel for guiding and holding drill and line pipes on the tubular truss rods - Google Patents

Abstract

"Bracket for drilling and line pipes in shaft-loaded truss structures made of large pipes, especially in drilling rigs."

Description

The invention relates to a body made of cast steel for guiding and holding drilling and conduit pipes on the tubular truss rods, in particular of drilling rigs, consisting of a substantially ring-shaped one Guide part and a supporting beam with cast welding collar.

Such drilling and line pipes, which are used for a wide variety of purposes on the drilling rigs in the sea are generally under heavy stress from wave and flow forces. you will be therefore connected at several heights with the tubes of the truss system of these islands in order to break through to avoid. In general, the connection should not be rigid. You must allow a threading and accordingly a small margin for Bohrbzw. Own conduit out.

Known solutions use a guide ring welded from sheet metal with a conical attachment, the is welded to the truss pipes with sheet metal brackets. These solutions have proven to be extraordinary exposed to fatigue because they contain large wave attack surfaces and therefore in addition to the stresses from the support of the Bohrbzw. Line pipes suffer further strong wave surges.

To alleviate the fatigue load, in Recently proposed to use the material cast steel with which the welds within this Body can be avoided and the fatigue resistance is improved. But the shape of these bodies is not significantly different from that of the sheet metal constructions. The large wave attack surfaces are with this solution is not reduced, because when welding the cast steel body to the framework tube for recording the bending threads arranged wide welding seams had to be, which in turn made thin-walled hollow cast bodies necessary. These thin-walled In addition, hollow cast bodies are complex in terms of casting technology and unfavorable under operating conditions check.

The invention is based on the object of all shaft attack surfaces To reduce such bodies to a minimum and at the same time reduce the stress concentration factors to keep as low as possible when introducing the forces and moments into the truss tube. the The solution to the problem consists in the features characterized in claim 1.

The solution is therefore essentially through the choice of one that is inserted through the framework tube Supporting beam achieved with a massive cross-section, with a second cast welding collar is provided on the opposite side of the framework tube Welding collars allow welding into the pipe at two separate points, so that all forces on two Introductory parts are distributed and the absorption of the bending moments durck the relatively large The distance between the two welding collars is greatly simplified. Such a support beam must be used for For the purpose of absorbing the force from the drill pipe or pipe, have a sleeve that supports the drill pipe or pipe. Line pipe either as a fork partially or as a ring completely encloses.

It is particularly advantageous to place the supporting beam in the central area, that is to say between the drill pipe or conduit pipe on the one hand and half-timbered pipe on the other hand, to form with a larger cross-sectional area and at both ends to provide gradually decreasing cross-sectional areas. This allows the arrangement of a central feeder without affecting the directional solidification, and at the same time means an ideal adaptation of the resistance or moments of inertia to the course of the bending moments in the supporting beam, which are their maximum value have the welding collar facing the drilling or conduit pipe and to zero towards the ends decrease.

The part of the support beam surrounding the guide area can be used for the purpose of facilitating the Threading also has a number of centering pins which are cast on in a very simple way.

Finally, the support beam can also have one in the central area have kinked axis. This results in two from the geometry of the drilling rig Special cases recorded:

On the one hand, the kinking in the plane normal to the axis of the truss tube allows a particularly small amount Distance between the truss pipe and the drilling or conduit pipe, and on the other hand, one achieves through the Bend in a plane parallel to the axis of the truss pipe that the drill pipe or pipe particularly close to the corner points of the island framework can be advanced. These two special cases are of great importance to the overall design an oil rig; because the drill pipe grid prescribed by the company forces the designer sometimes to complex and fatigue-prone framework systems. With the proposals according to the invention the draftsman receives a substantial

greater scope for designing the framework.

In summary, it should be mentioned that the massive construction of the support beam as a whole, the pushing through of the supporting beam through the framework tube and the compact design of the guide system to one with none of the previously known solutions achieve a reduction in shaft forces and an increase in fatigue safety leads. This means a drastic reduction in inspection and inspection costs for the operation of the oil rig Repair expenses and will lead to a reduction of the unfortunately very frequent diving accidents today.

In the drawings, embodiments of the invention are shown schematically

F i g. 1 is a top view of a pipe holder with an open Guide part, in which a support beam (1) opens into two forks (5), which softens the guide area (2) partially enclose; here is the supporting beam (1) with two welding collars (3) and (5) in the framework tube (4) shrink wrapped,

F i g. 2 shows a longitudinal section along line AA in FIG. 1, which in turn shows the supporting beam (1) with its two welding collars (3) and (5) within the framework tube and at the same time lets you know the centering pin (8),

3 shows the top view of a pipe holder with closed Guide part in which the forks (6) unite to form a closed ring (7), which the Completely encloses the guide area (2),

F i g. 4 a longitudinal section through a pipe holder with a bent supporting beam axis,

F i g. 5 the top view of a pipe holder with a bent supporting beam axis.

For this purpose 2 sheets of drawings

35

40

55

bO

Claims (5)

Patent claims: 1. Body made of cast steel for guiding and holding drill and line pipes on the tubular Truss rods, in particular from drilling rigs, consisting of a substantially ring-shaped one Guide part and a supporting beam with cast welding collar, characterized in that that the supporting beam (1) is designed as a beam with a solid cross-section extending from the Guide area (2) out beyond the cast welding collar (3) into the interior of the framework tube (4) continues, on the opposite side of the truss tube (4) a second, also has cast-on welding collar (5) and is located on the guide area (2) facing Side forks into two branches (6) which at least partially enclose the guide area (2). 2. Body according to claim 1, characterized in that the cy intersection surfaces in the central area of the support beam (1) are largest and both in the two forks (6) of the guide area (2) and gradually decrease in the interior of the framework tube (4) towards the ends. 3. Body according to claims 1 and 2, characterized in that the forks (6) of the guide area (2) form a closed ring (7) unite. 4. Body according to claims 1 to 3, characterized in that on the branch forks (6) at least three centering pins (8) are cast. 5. Body according to the claims. 1 to 4, characterized in that the axis of the supporting beam (1) is bent at an angle at ^ in the central region.