Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
  • E21B17/02—Couplings; joints
  • E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
  • E21B17/042—Threaded
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L15/00—Screw-threaded joints; Forms of screw-threads for such joints
  • F16L15/001—Screw-threaded joints; Forms of screw-threads for such joints with conical threads
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L15/00—Screw-threaded joints; Forms of screw-threads for such joints
  • F16L15/04—Screw-threaded joints; Forms of screw-threads for such joints with additional sealings

Definitions

• the present invention relates to a threaded joint for steel tube, usable in particular for the petroleum industry, of the type consisting of a sleeve and two male elements the ends of which are engaged axially against one another.
• tube joints used in the petroleum industry must have a certain number of characteristics which are difficult to reconcile and which consist in particular in that the joint, while being easy to machine and insensitive to damage, makes it possible to ensure a perfect sealing against very high pressures which are exerted either inside or outside the joint and this even in the hypothesis where the joint is subjected to bending and to significant traction or compression axial.
• seal elements can be interchanged without this having a detrimental influence on the quality of the seal which is obtained during the new screwing of the seal with other elements.
• the threaded joints currently used in the petroleum industry comprise male and female threads which are most often conical and which ensure the mechanical retention of two male elements in a female sleeve, in particular supporting the axial pulls which are exerted on the joint.
• Seals of this type also comprise at least a couple of sealing surfaces which are placed in such a way that when screwing the seal, these sealing surfaces come into contact with each other with sufficient pressure to obtain the seal which is generally of the metal-metal type.
• Joints of this type are characterized by the fact that a first element of the joint comprises, over at least a certain length of its thread, a lining made of synthetic material, the volume and shape of which are exactly sp volume and shape of the game which would exist 4 the state visited between said first element and the second element whose dimensions caraienr to the limit of machining tolerances which allows the greatest possible play between the elements in the screwed state of the joint.
• the shape of the mass of synthetic material thus attached to the first element does not have to be modified during screwing to adapt to the shape of the thread of the second entirely metallic element as was previously known, because that it simply undergoes a slight compression which results from the machining tolerances.
• urethane elastomers as synthetic material such as, for example, Polathane XPE or RIM 160 with a microcellular structure, polycarbonates, polyolefins, or polyamides.
• the present invention relates to a joint of this type in which the two male elements are joined by a sleeve which does not have an internal stop, the two ends of the male elements coming to bear one against the other during the screwing of the joint and in which, the synthetic material which is applied to the interior of the sleeve at the level of the thread continues continuously in the central zone of the sleeve in the vicinity of the place where the ends of the male elements meet.
• the present invention relates to a joint for steel tube intended in particular for the petroleum industry, of the type in which the threaded ends of two male elements are joined together by a sleeve having a double thread, the ends of the elements males abutting one against the other during screwing, joint characterized in that the sleeve has a composite structure and that it comprises over at least a certain length of each of its threads a lining of synthetic material whose volume and the shape corresponds exactly to the volume and the shape of the clearance which would exist in the screwed state between the metal part of said composite sleeve and each of the corresponding male elements whose dimensions would be at the machining tolerance limit which allows the greatest possible clearance in the screwed state of the seal, said packing in material synthetic extending in the inner median part of the sleeve, where it has two concave frustoconical surfaces arranged symmetrically on either side of the median plane of the sleeve in which the ends of the miles elements come into contact, the ends of the male
• the active flanks of the threads which support the axial tractior exerted on the joint form a reentrant angle inclined by at least 5th relative to a plane perpendicular to the axis of the joint.
• the parts of the plastic lining which are fixed to the sleeve and which are located between the concave frustoconical surfaces and the threads have an internal diameter greater than or less than the maximum possible diameter of the corresponding part of the male elements, so that, when the joint is screwed on, the male elements do not interfere with these parts of the garaisshiel
• the seals according to the invention have several advantages over known seals.
• the contacts between the convex frustoconical chamfers of the ends of the male elements and the concave frustoconical surfaces of the sleeve lining provide an additional seal which is added to the seal obtained at the threads and to the seal which is obtained by the fact that the ends of the male elements are applied one against the other.
• a sleeve is obtained, thanks to the invention, the entire internal surface of which is coated with a lining of synthetic material, which makes it possible to avoid all the problems of corrosion on this surface.
• a high quality seal is obtained belonging to the group of so-called “Premium” seals, the machining of which is very simple (practically equivalent to that of a “Buttress” seal), which is impervious to high oil or gas pressures and which is completely monolithic with a low hooping at the level of the thread and an abutment of the ends of the male elements.
• seal according to the invention can be manufactured as indicated in the description of French patent application No. 84 15551 filed on October 10, 1984.
• FIG. 1 represents a schematic sectional view of part of a joint according to the invention
• FIG. 2 is a partial sectional view of the central part of the sleeve of FIG. 1,
• FIG. 3 is a partial sectional view of the ends of the male elements of FIG. 1,
• FIG. 4 is a sectional view of a variant of the threads having inverted load-bearing sides
• FIG. 5 is a sectional view of a device which allows for the filling of synthetic material on the inner sleeve surface.
• This seal is constituted by a sleeve 1 provided at each of its ends with an internal frustoconical thread 2 and inside which the ends of two male elements 3 and 3 ′ come into engagement which are also provided with corresponding external threads 4 .
• FIG. 1 only the end of the male element 3 is shown, the configuration of the male element 3 'being identical, (that is to say symmetrical) to that of the end of the element male 3.
• the free space between the male threads 4 of the ends of the male elements and the female threads 2 of the sleeve are filled with a synthetic lining 5, which in the present case, is fixed on the internal surface of the sleeve 1.
• the lining 5 continues on the central cylindrical surface 6 of the sleeve.
• the two concave frustoconical surfaces 9 and 9 ' which are real. sées according to the invention on the lining 5 synthetic material are connected in a plane 7, according to which the end faces 8 and 8 'of the male elements 3 and 3' are applied one against the other.
• the ends 8 and 8 'of the male elements 3 and 3' which meet in the plane 7 which also corresponds to the line 9a of Figure 2.
• the external peripheries of the miles elements comprise convex chamfers 10 and 10 ′, the shape of which corresponds to that of the concave frustoconical surfaces 9 and 9 ′ of the chamfer.
• the dimensions and the positions of the concave frustoconical surfaces 9 and 9 ′ of the sleeve 2 and of the convex frustoconical chamfers 10 and 10 ′ of the miles elements are such as when the joint is screwed, at the moment when the ends 8 and 8 'of the male elements come into contact, the chamfers 10 and 10' already exert compression on the frustoconical surfaces 9 and 9 'of the sleeve so as to provide an additional seal.
• the chamfers 10 and 10 ′ can exert a compression of 0.2 to 0.6 mm from the frustoconical surfaces 9 and 9 ′, measured perpendicular to these surfaces.
• the internal diameter of the surfaces 11 and 11' of the lining of the sleeve on either side of the frustoconical surfaces 9, 9 ' is greater than the external diameter of the parts 12 and 12' of the elements male, so that, during the screwing, there is no deformation of the parts 11 and 11 'of the plastic lining.
• FIG. 4 shows a variant of the thread of the seal shown in FIGS. 1 to 3.
• This figure which is on a larger scale, shows the sleeve 1 and the end of the male element 3, which are respectively provided with threads 2 and 4.
• the load-bearing face 4a of the thread forms a re-entrant angle A, being offset to the left with respect to the perpendicular to the axis of the joint.
• the angle A it be a value greater than 5 °.
• the angle B made by the non-load-bearing rear face of the thread with the plane perpendicular to the axis of the joint. This angle B can vary to a large extent, for example, from 10 to 45 °.
• FIG. 5 shows how it is possible to produce the plastic lining according to the invention.
• the sleeve 1 provided with its thread and inside which are screwed two identical mandrels 12 and 12 'whose external surface corresponds to the external surface of the end of the male tubes, surface of which the dimensions correspond to the minimum manufacturing tolerances.
• the external peripheries of the miles elements comprise convex chamfers 10 and 10 ′, the shape of which corresponds to that of the concave frustoconical surfaces 9 and 9 ′ of the chamfer.
• the dimensions and the positions of concave frustoconical surfaces 9 and 9 ′ of the sleeve 2 and of the convex frustoconical chamfers 10 and 10 ′ of the miles elements are such as when the joint is screwed, when the ends 8 and 8 'of the miles elements come into contact, the chamfers 10 and 10' already exert compression on the frustoconical surfaces 9 and 9 'of the sleeve so as to provide additional sealing.
• the chamfers 10 and 10 ′ can exert a compression of 0.2 to 0.6 mm from the frustoconical surfaces 9 and 9 ′, measured perpendicular to these surfaces.
• the internal diameter of the surfaces 11 and 11 'of the lining of the sleeve on either side of the frustoconical surfaces 9, 9' is greater than the external diameter of the parts 12 and 12 'of the miles elements , so that, during the screwing, there is no deformation of the parts 11 and 11 'of the plastic lining.
• FIG. 4 shows a variant of the thread of the seal shown in FIGS. 1 to 3.
• This figure which is on a larger scale, shows the sleeve 1 and the end of the male element 3, which are respectively provided with threads 2 and 4.
• the load-bearing face 4a of the thread forms a re-entrant angle A, being offset to the left with respect to the perpendicular to the axis of the joint.
• the angle A it be a value greater than 5 °.
• the angle B made by the non-load-bearing rear face of the thread with the plane perpendicular to the axis of the joint. This angle B can vary to a large extent, for example, from 10 to 45 °.
• FIG. 5 shows how it is possible to produce the lining of synthetic material according to the invention.
• the sleeve 1 provided with its thread and inside which are screwed two identical mandrels 12 and 12 'whose external surface corresponds to the external surface of the end of the miles tubes, surface of which the dimensions correspond to the minimum manufacturing tolerances.
• These mandrels 12 and 12 ' are provided with a series of longitudinal channels 13 (of which only one is shown in FIG. 5) which are themselves joined to the volume which is located between the sleeve 1 and the mandrels by secondary channels 14 It is thus conceivable that by injecting into the channels 13 synthetic material such as those which have been described previously, it is possible to produce the lining in accordance with the invention.
• the lining 5 can be produced both at the threading and on the cylindrical part 6 of the sleeve where the frustoconical surfaces and 9 ′ are thus obtained.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Mining & Mineral Resources (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Fluid Mechanics (AREA)
• Environmental & Geological Engineering (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
• Mutual Connection Of Rods And Tubes (AREA)
• Gasket Seals (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9331139

Family Applications (1)

Country Status (4)

Cited By (5)

Families Citing this family (4)

Citations (4)

Family Cites Families (2)

• 1986
  • 1986-01-15 FR FR8600509A patent/FR2592935B1/fr not_active Expired
• 1987
  • 1987-01-15 WO PCT/FR1987/000015 patent/WO1987004505A1/fr unknown
  • 1987-01-15 EP EP87400083A patent/EP0233802A1/fr not_active Withdrawn
  • 1987-01-15 JP JP62500770A patent/JPS63502608A/ja active Granted

Patent Citations (4)

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