Mannesmann Aktiengesellschaft

Vallourec Mannesmann Oil & Gas Germany Gmbh

Mannesmann Aktiengellschaft

Erich Quadflieg

Friedrich Lenze

Gerhard Krug

Josef Siekmeyer

Gerd Pfeiffer

Thomas Gigowski

Christoph Bunsen

Krug, Gerhard

Martin Schl&uuml;ter

Martin Schluter

A pipe joint with a sleeve element, which has an internal thread, and with a spigot element, which has an external thread which can be screwed to said internal thread. One element has a constant pitch throughout and the other element, with two sections extending in each case from the ends of the threaded length is likewise provided with a constant pitch. The other element has more than two sections with a pitch which is constant within the section but is different from the first-mentioned element, it being the case that the pitch difference at least of one section is in the opposite direction, in terms of sign, to the rest of the sections. The pitch difference of one section is at least double that of the adjacent sections and in the screwed-together position, in the section with the large pitch difference, the thread play and the thread tolerances are compensated and the load flank of one corner tooth of this section, with the guide flank of the other corner tooth, produces the basic bracing. The two adjacent sections, with their load and/or guide flanks, build up the thread bracing until the desired thread torque has been reached.

Pipe connector

A boring rod connector with a journal element that has a tapered external thread section located between an outer shoulder and a journal face, a thread-free section located between the outer shoulder and the external thread section, and a thread-free section located between the external thread section and the journal face, and with a sleeve element that can be screwed to the journal element and has a tapered internal thread section located between an inner shoulder and a sleeve face, a thread-free section located between the inner shoulder and the internal thread section, and a thread-free section located between the internal thread section and the sleeve face. The thread-free sections of the journal element and the sleeve element located in the area of the inner shoulder that, when a screw connected exists, lie opposite to each other, have a different length than the thread-free sections of the journal element and the sleeve element located in the region of the inner shoulder. The inner shoulder forms the primary shoulder and, after the drill pipe connector is assembled and screwed to up to 90% of its yield point, the journal face tightens on the inner shoulder up to a pressure that exceeds the pressure exerted by the sleeve face on the outer shoulder, whereby the sleeve face tightens mainly on the outer shoulder when an additional torque occurs during boring. The thread-free sections located in the region of the inner shoulder are at least twice as long as the thread-free sections located in the region of the outer shoulder.

Drill rod coupling

A pipe connector having a pin element having a tapered outer threaded section between an external shoulder and a pin end face, a first threadless pin section between the external shoulder and the outer threaded section, and a second threadless pin section between the outer threaded section and the pin end face. Provided for threaded engagement with the pin element is a box element having a tapered inner threaded section between an internal shoulder and a box end face, a first threadless box section between the internal shoulder and the inner threaded section, and a second threadless box section between the inner threaded section and the box end face. Suitably, the second threadless pin section and the first threadless box section in the area of the internal joint is at least twice as long as the first threadless pin section and the second threadless box section in the area of the external joint.

Pipe joint

A screwed pipe joint with a bell for connecting two pipes of a drill pipe string. The screwed pipe joint includes, in opposed relation, a first pipe having a first tapered threaded end (10) and a second pipe having a second tapered threaded end (11), the first tapered pipe end and the second tapered pipe end having a different taper and pitch, and being shaped so that when the pipes are joined they are form-locked and having an axial clearance (23, 23') therebetween; and a bell having a first and second threaded section (7, 8) complementary to and for engagement with the first and second threaded pipe ends, and an unthreaded section (9) therebetween and a radially inward projecting shoulder (24) on the unthreaded section (9) of the bell (6) opposite the first pipe (2); the first and second pipe ends having respective annular recesses (14, 13) therein defining, with the unthreaded bell section (9), an annular space (15) therebetween; a sealing sleeve within the annular space (15) having an outside diameter smaller than the inside diameter of the unthreaded section (9) of the bell (6) and being axially fixed in the recess (14) of the first pipe end.

Screwed pipe joint

A drill pipe coupling includes a coupling member (2) having an unthreaded central section (13) with a cylindrical bore (26) therein and an outer shoulder (11,12) on each side thereof. Adjoining the shoulders are respective conical external threads for threading into an internal correspondingly threaded upset head section of a drill pipe formed as a bell elements and including end surfaces (9,10). The drill pipe has an undeformed cylindrical bore (14) connected to the threaded upset head. The drill pipe end surfaces (9,10) sealingly abut the outer shoulders (11,12) of the central section (13) when the pipes are joined together. The drill pipe has an intermediate section (16) adjoining the cylindrical bore (14) and has an inside diameter which decreases in the direction toward the threaded section (5, 6). A cylindrical bore section (18) adjacent the intermediate section (16) extends to the threaded section (5,6) and a rounded transition is located between the cylindrical bore (14) of the undeformed pipe (8) and the intermediate section (16). The drill pipe has an outer shoulder (33) opposite the cylindrical bore section (18) and the outside diameter of the drill pipe in the upset region (23) of the shoulder (33) is identical to or greater than the outside diameter (21) of the undeformed pipe (8) and the length of the region (23) is greater than the length of the intermediate section (16).

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Krefeld, Germany

Erich Quadflieg