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
  • E21B17/043—Threaded with locking means
• • 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
  • F16L15/003—Screw-threaded joints; Forms of screw-threads for such joints with conical threads with sealing rings
• • 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
  • F16L15/004—Screw-threaded joints; Forms of screw-threads for such joints with conical threads with axial sealings having at least one plastically deformable sealing surface

Definitions

• This invention relates to a coupling. More particularly, it relates to a coupling between a first component and a second component, the first component being provided with an internal circular face and the second component being provided with an external circular face which is arranged to be received within the internal circular face, the external circular face may be in engagement with the internal circular face, and the circular faces being arranged to be displaceable relative to each other when a fluid pressure is present between the external circular face and the internal circular face.
• SKF couplings In other industries, it is common to use radially pretensionable couplings, often termed SKF couplings, in which an outer sleeve is slipped onto a conical face while a considerable hydraulic pressure is applied between the components. As the hydraulic pressure is bled off, the outer sleeve shrinks around the conical face and maintains a mechanically good connection between the components.
• a threaded coupling for steel pipes including a male portion and a female portion.
• One of the male and female portions includes a groove which has a length of at least one thread pitch and a depth which is larger than the thread height.
• a synthetic sealing means which has a volume and a shape substantially corresponding to the volume and shape of a space located between the threads of the male and female portions is placed in the groove. A portion of the threads of one of the portions is placed with great force against a portion of the threads of the other one of the portions.
• the invention has for its object to remedy or reduce at least one of the drawbacks of the prior art.
• a coupling is provided to provide a joint between a first component and a second component, the first component being provided with an internal circular receiving portion which includes an internal thread, and the second component being provided with an external circular insertion portion having a form being complementary to the receiving portion, the insertion portion including an external thread.
• the coupling further includes at least one fluid communica ⁇ tion channel arranged to communicate a pressurized fluid in between a portion of the first component and the second component.
• the thread may form a portion of the internal circular receiving portion and the external insertion portion.
• the thread may constitute the major part of the internal circular receiving portion and the external insertion portion.
• the thread absorbs the axial forces that arise through this kind of coupling operations.
• Other equipment for absorbing axial forces during assembly or disassembly work is thus superfluous.
• the first component may be defined by: a first shoulder; and a first flange arranged in an end portion of the receiving portion .
• the second component may be defined by: a second shoulder; and a second flange arranged in an end portion of the insertion portion.
• the pressurized fluid may be arranged to drive the receiving portion of the first component radially outwards relative to the insertion portion of the second component so that a torsional force that is required to provide a complete joining of the coupling, wherein at least one of: the second flange has been moved into abutment against the first shoulder; or the first flange has been moved into abutment against the second shoulder, is smaller than a torsional force required to break out a completely joined coupling from which the pressure fluid has been bled off.
• the thread may be formed with active flank faces which are slanted, the active flank face of the external thread having a smaller distance to the second flange at its outer diameter than at its inner diameter.
• active flank face is meant the side of the flank faces that has contact as the coupling is being screwed together. This has the effect of the threads providing a pre-tensioning effect when the pressure fluid between the first component and the second component is bled off, as the slanted active flank faces bring about an axial movement of the insertion portion inwards in the receiving portion.
• the pre-tensioning effect is particularly great if the coupling is formed in such a way that, in the assembled position, one of or both of: the second flange of the second component is arranged to hit the first shoulder of the first component; or the first flange of the first component is arranged to hit the second shoulder of the second component, before a top portion of the thread abuts against a bottom portion of the thread.
• the pre-tensioning effect that is provided by means of the slanted active flank faces will thereby lead to an increased clamping force between the flange/shoulder faces.
• the first component will shrink somewhat radially relative to the second component.
• the active flank face of the internal thread will therefore be moved inwards somewhat over the active flank face of the external thread. This has the effect of the first component being moved further onto the second component in the axial direction. The movement leads to an axial pre-tensioning arising between the first flange and the second flange.
• the circular insertion portion and the receiving portion are conical.
• the receiving portion may include at least one circular face without threads
• the insertion portion may include at least one circular face without threads.
• the circular faces may be formed with a smooth surface which is fit to provide a sealing surface in the coupling.
• the at least one circular face in the receiving portion may be divided, in the axial direction, into an upper portion and into a lower portion, and the at least one face in the insertion portion may be divided, in the axial direction, into an upper portion and into a lower portion.
• the thread In the axial direction, the thread may be between the circular faces.
• the faces may provide a seal on both sides of the thread.
• the pressure fluid may be constituted by a viscous fluid which may be squeezed out between the components. If a hydraulic fluid is used as the pressure fluid, it may, in some cases, be an advantage if the coupling is further provided with seals placed between the receiving portion and the insertion portion to be able to define a portion arranged to be in fluid communication with the fluid communication channel.
• At least one of the insertion portion and the receiving portion may be provided with one or more pressure-fluid distribution grooves.
• a method of providing a coupling between a first component and a second component comprising the steps of:
• the receiving portion may be defined by a first shoulder and by a first flange arranged in an end portion of the receiving portion.
• the insertion portion may be defined by a second shoulder and a second flange arranged in an end portion of the insertion portion.
• said stop point may be provided by means of one or both of: the second flange, as this is moved into abutment against the first shoulder; or the first flange, as this is moved into abutment against the second shoulder.
• the predetermined torque in step a) may be maintained through the steps b) and c). This may be achieved by means of a control system which opens to pressure fluid supply through the pressure-fluid supply channel as soon as the predetermined torque has been reached and continuing the supply of pressure fluid until complete coupling has been achieved, after which the supply of pressure fluid ceases and the pressure is reduced or bled off, for example to the ambient pressure of the coupling.
• a method for unscrewing a coupling between a first component and a second component including the steps of:
• the pressure is bled off before the first component is completely separated from the second component.
• the pressure will be bled off as soon as unscrewing has been started, but this depends on the friction that occurs between the components.
• the relative change in diameter that occurs between the components when pressure fluid is supplied between the circular faces will thus have the effect of enabling relatively easy unscrewing of the components.
• the device in accordance with the invention enables assembling and disassembling of relatively rigid, torque-resistant couplings without the use of corresponding, known heavy-duty equipment. Thus, it is possible to carry out this kind of work even in areas where heavy tools for the assembling and disassembling of prior-art couplings are not available.
• Figure 1 shows, in perspective, a coupling according to the invention between a first component and a second component
• Figure 2 shows, on a larger scale, an axial section through the coupling in the disassembled position
• Figure 3 shows the same as figure 2, but during the assembling of the coupling
• Figure 4a shows, on a larger scale still, a section of a portion of the coupling in a position just before it has been finally made up, but after a fluid pressure has been introduced;
• Figure 4b shows the same as figure 4a, but after the coupling has been finally made up and before a fluid pressure has been bled off;
• Figure 5 shows the same as figure 4b, but after the fluid pressure has been bled off
• Figure 6 shows, on a larger scale, the first component shown in figure 2, but in which a portion of the component is further provided with an internal helical groove.
• Indications of position or orientation such as “over”, “under”, “upper”, “lower”, indicate the relative positioning in relation to what is shown in the figures.
• the reference numeral 1 indicates a coupling including a first compo- nent 2 and a second component 4.
• the first component 2 is formed with a conical, internal circular face 6 which includes an axial, internal thread 8.
• the internal circular face 6 of the first component 2 is arranged to receive a portion of the second component 4.
• the internal circular face 6 of the first component 2 will therefore also be referred to as a circular receiving portion 6.
• the circular receiving portion 6 is defined by a first shoulder 7 and by a first flange 12 arranged in an upper end portion 10 of the first component 2.
• first shoulder 7 is shown as being at right angles to a longitudinal axis L, it shall be understood that, in alternative embodiments (not shown), the shoulder 7 may be, for example, slanted relative to the longitudinal axis L, have a curved shape, be stepped or a combination of two or more thereof.
• the curved shape may be, for example, but is not limited to concave or convex.
• the circular receiving portion 6 is divided into an upper portion 6a and a lower portion 6b which are on either side of the internal thread 8.
• the upper portion 6a and the lower portion 6b have different diameter areas so that a conical receiving portion 6 is provided.
• the second component 4 is formed with a conical, external circular face 20.
• the external circular face 20 is arranged to be inserted into the receiving portion 6 of the first component 2.
• the external circular face 20 of the second component 4 will therefore also be referred to, in what follows, as a circular insertion portion 20.
• the insertion portion 20 is formed complementary to the receiving portion 6 and includes an external thread 22.
• the insertion portion 20 is defined by a second shoulder 30 and by a second flange 21 which is arranged in a lower end portion 24 of the second component 4.
• the circular insertion portion 20 is divided into an upper portion 20a and a lower portion 20b which are on either side of the external thread 22.
• the upper portion 20a complementarily fits the upper portion 6a of the first component 2.
• the lower portion 20b complementarily fits in the lower portion 6b.
• the external thread 22 fits in the internal thread 8.
• the first shoulder 7 of the first component 2 complementarily fits the second flange 21 of the second component 4, and the first flange 12 of the first component complemen- tartly fits the second shoulder 30 of the second component 4.
• a seal may be achieved both between the end portions 30, 12; 21, 7 of the coupling 1 and between the side portions 20a, 6a; 20b, 6b and also between the threaded portions 22, 8.
• the coupling 1 further includes a fluid communication channel 18 which is arranged to be connected to a pressure-fluid source (not shown) so that a pressure fluid may be communicated in between a portion of the first component 2 and the second component 4.
• the purpose of the pressure fluid is to exert so large a pressure that the receiving portion 6 of the first component 2 is driven radially outwards relative to the insertion portion 20 of the second component 4 (see figure 4a) so that frictional forces that occur between the receiving portion 2 and the insertion portion 20 will be reduced.
• the first component 2 is provided with a first seal 16 which is positioned in a first groove 14.
• the first groove 14 is arranged close to the upper end portion 10.
• the second component 4 is provided with a second seal 28 which is arranged in a second groove 26.
• the second groove 26 is arranged close to the lower end portion 24 of the second component 4.
• seals 16, 28 Is to prevent, or at least limit, leakage of pressure fluid which is introduced via the fluid communication channel 18.
• the seals 16, 28 are particularly useful when a thinly liquid fluid is introduced through the fluid communication channel 18, or when leakage of pressure fluid is undesirable.
• the seal 16, 28 could also provide an extra sealing barrier for a pipeline in which the coupling 1 is included.
• the coupling 1 could function satisfactorily even without said seals 16, 28, but leakage out from the interface between the receiving portion 6 and the insertion portion 20 will then occur while assembling Is in progress.
• Figure 6 shows a receiving portion 6 without a seal of the kind that is shown, for example, in figure 2.
• Figures 4a and 4b show the coupling 1 as a pressure fluid has been supplied through the fluid communication channel 18 (see for example figure 2) and forces the receiving portion 6 and the insertion portion 20 apart radially. It should be underlined that the distances or gaps between the side portions 6a and 20a, and between a top portion 8' of the thread 8 and a bottom portion 22' of the thread 22 have been exaggerated for illustrative reasons.
• the coupling 1 may be fully made up until at least one of: the second flange 21 has been brought into abutment against the first shoulder 7; or the first flange 12 has been brought into abutment against the second shoulder 30 as shown in figure 4b.
• the internal thread flanks 32 and the external thread flanks 34 abutting against each other when the coupling 1 has been assembled are somewhat slanted in the embodiment shown.
• the first component shown in figure 2 is shown on a larger scale, but in which a portion of the component is further provided with an internal helical groove 42.
• the purpose of the groove 42 is primarily to provide a rapid and even distribution of pressure fluid, introduced through the communication channel 18, in the space between the receiving portion 6 and the insertion portion 20.
• the groove 42 is particularly useful when the coupling 1 is provided with only one fluid communication channel 18 as shown.
• the coupling according to the present invention may be provided by means of relatively simple torqueing tools instead of heavy- duty tools like power tongs, for example, which are known from the petroleum industry. This is because the friction between the components is reduced by means of the pressure fluid during the connecting. In addition, during the connecting, the threads absorb the axial forces that arise during this kind of connecting operations. Other equipment for absorbing axial forces during assembling and disassembling work is thus superfluous.
• the device and method in accordance with the invention enabling the assembling and disassembling of relatively rigid, torque-resistant couplings without the use of correspondingly heavy-duty equipment, it is thus possible to carry out this kind of operations even in areas in which heavy tools for assembling and disassembling prior art couplings are not available.
• the invention may thus entail the ability for the coupling to be quickly screwed or unscrewed. Further, the risk of deforming the receiving portion because of large clamping forces from the assembling equipment will at least be considerably reduced. Large clamping forces are particularly relevant for unscrewing or "breaking" prior-art threaded connections which have been what a person skilled in the art will know as "overtorqued".
• a further advantage of the coupling according to the present invention is that it makes it easier to predetermine a correct pre-tensioning of the connection. This is because the friction that occurs when the coupling is being made up is very much lower than what is the case with known threaded connections. The friction that occurs as the coupling according to the invention is being made up will thus have relatively little influence when calculating the desired pre-tensioning.
• the expected lifetime of the coupling will increase both because the threads are subjected to less wear and because the equipment or tools used to form or unscrew the_ coupling will exert less wear on the surface of the coupling against which the tool is placed.
• the wall thickness of the coupling may be reduced in consequence of less clamping force from the assembling tool. A smaller wall thickness could result in improved downhole hy- draulic properties, which could in turn make longer wells possible.

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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)
• Joints With Pressure Members (AREA)
• Quick-Acting Or Multi-Walled Pipe Joints (AREA)

Applications Claiming Priority (4)

Publications (1)

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Family Applications (1)

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Cited By (2)

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Citations (4)

• 2012
  • 2012-12-13 NO NO20121504A patent/NO20121504A1/no not_active Application Discontinuation
  • 2012-12-20 WO PCT/NO2012/050254 patent/WO2013115649A1/fr not_active Ceased

Patent Citations (4)

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