CA1191172A - Screw coupling joint - Google Patents
Screw coupling jointInfo
- Publication number
- CA1191172A CA1191172A CA000403231A CA403231A CA1191172A CA 1191172 A CA1191172 A CA 1191172A CA 000403231 A CA000403231 A CA 000403231A CA 403231 A CA403231 A CA 403231A CA 1191172 A CA1191172 A CA 1191172A
- Authority
- CA
- Canada
- Prior art keywords
- screw
- coupling joint
- packing material
- male screw
- female screw
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000008878 coupling Effects 0.000 title claims abstract description 46
- 238000010168 coupling process Methods 0.000 title claims abstract description 46
- 238000005859 coupling reaction Methods 0.000 title claims abstract description 46
- 239000000463 material Substances 0.000 claims abstract description 36
- 238000012856 packing Methods 0.000 claims abstract description 32
- 239000002184 metal Substances 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 description 6
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 238000007789 sealing Methods 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 229920003002 synthetic resin Polymers 0.000 description 2
- 239000000057 synthetic resin Substances 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004299 exfoliation Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000004513 sizing Methods 0.000 description 1
Classifications
-
- 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
-
- 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
- F16L15/04—Screw-threaded joints; Forms of screw-threads for such joints with additional sealings
Landscapes
- 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)
- Joints With Pressure Members (AREA)
- Earth Drilling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A screw coupling joint makes a direct end-to-end connection between mutual pipes, or via a sleeve, by providing a step portion on an inner surface about an interior of a female screw portion of the coupling joint, so that the step portion and an end portion of a male screw portion are contacted via packing material.
A screw coupling joint makes a direct end-to-end connection between mutual pipes, or via a sleeve, by providing a step portion on an inner surface about an interior of a female screw portion of the coupling joint, so that the step portion and an end portion of a male screw portion are contacted via packing material.
Description
~.~a~ 7~
q'hi5 lr~ver~tion relates to a screw coup]ing joirl~, more especially to a screw coupliny joint Eor rnakirlq erld-to end connections between pipes for an oil or gas well.
Casing pipes or tubing pipes Eor oil or gas wells which cornprise a plurality of pipe elements connec-ted -to each other at a large depth of -the earth. For satisfactory use in service, -the couplin~ portion is re~uired to have sufficient strength and sealing ability. In one conventional structure of coupling joint, the pipe is defined with a male screw on one end thereof and with a female screw on the o-ther end, and is provided with a step which forms a stop on an outer circumferential surface about the -terminal part of the rnale screw portion. The outer circumference surface on the front end portion of the male screw and the inner circumferential surface oE the female screw are provided with smooth tapered faces. ~nder a condition in which the pipes of such structure are connected at the ends, the front end portion of the female screw contacts the step so -that a seal is forrned, and the smooth face of -the outer circumferential surface at the front end portion of the male screw is contacted with the smooth face of the inner circumferential surface of the female screw so that another seal is formed. In such a structure having the stop at the male screw, if the female screw contacts the stop of the male screw, the male screw cannot be further advanced. Therefore, in order to provide proper sealing between the smooth surface of the male screw and the smooth surface of the female screw, the diameters of those smooth surfaces need to be determined within severe production tolerances.
In the case of a coupling joint using a sleeve, generally a female screw is formed on the sleeve, and a male :~Lq~
screw i~ formed about an end of the pipe, arld a step :i5 formed on the interior of the sleeve to serve as a stop.
Tapered smooth faces are provided on the outer circumferential surface on the front end of the male screw and the inner circumferential surface of the interior of the female screw.
In this structure, when the front end portion of the male screw contacts the step, the seal is made between the smooth surface of the male screw and the smooth surface of the female screw. If the male screw contacts the step of the sleeve at its end point, a further screwing cannot be effected.
Therefore severe production tolerances are required here as mentioned above.
If the taper of the smooth surface is 1/16 and if the diameter of the pipe changes O.lmm, the position of the end portion of the female screw or the male screw changes as much as 1.6mm in length of the pipe, and the production tolerance is so severe that it is difficul-t to form a stab]e seal.
Further, the abo~e mentioned coupling joint has difficulties as more particularly indicated hereinafter.
In the structure of the former coupling joint, a clearance is made between the front end portion of the male screw and the terminal portion of the female screw, as a consequence eddy currents of fluid develop in this clearance and corrosion occurs there. If a casing pipe were substituted for such structure, the tubing pipe or the drill pipe to be served within the casing pipe would be caught, due to the clearance, at the front end portion of the male screw, and damage would occur.
In the structure of the latter coupling joint, since the front end portion of the male screw and the step portion of the female screw contact each other within the coupling joint, there OCC-lrS the disadvallt~lcJe that corroslon resi3tant coating thereon comes o~f due to the metal-to--metal contact.
~ he present invention seeks to provide an irnprovement in this kind of coupling joint, ancl to overcome the disadvan-tages mentioned above.
The invention seeks to provide a coupling structure which may form a satisfactory seal without requiring severe production tolerances.
The invention also seeks to provide a coupling structure which may prevent corrosion within the pipe at the connection of the coupling joint, in which the front end portion of the female screw contacts the step portion on the outer circumfexential surface about the terminal part of the male screw.
The invention furtner seeks to provide a coupling structure which may prevent damage at the inner wall of the coupling of the type mentioned above, when a tubing pipe or the drill pipe is served therein.
Still further the invention seeks to provide a coupling structure which may form the required seal between the outer circumference of the smooth surface at the front end portion of the male screw portion and the inner circum-ference of the smooth surface at the inner part of the female screw portion, even though the production tolerance is large in a coupling joint in which the end portion of the male screw contacts a step portion at the inner part of -the *emale screw.
The invention also seeks to provide a coupling structure which may avoid damage or exfoliation of ~ corrosion resistant coating.
'7~
In accordance with the invention there iB provid~d a screw coupling joint for a pipe to be used in an oil or ~as well, in which plpes are directly contacte~ end-to-end or via a sleeve, comprising a fernale screw having a step at an inner part thereof for contact with a front end portion of a male screw via a packing material to provide a first and a second seal formed between the front end portion of the male screw and the packing material.
In particular the invention provides a screw coupling joint for end~to-end connections between pipes for oil or gas wells comprising a female screw means and a male screw means adapted to engage the female screw means to form said joint, said female screw means having a step defined in an inner surface of an inner part, and said male screw means having a first end, and a packing material between said front end and said step.
In the case of a coupling joint in which the front end portion of the female screw contacts a step defined on the outer circumference about the terminal of the male screw, the pac~cing material closes the clearance between the front end portion of the male screw and the terminal part of the female screw.
By contacting the front end portion of the male screw to the step on the inner circumferential surface at the inner part of the female screw, the production tolerances are absorbed by compression of the packing material, and metal-to-metal contact is avoided between the front end portion of the male screw and the step at the inner part of the female screw.
The invention is illustrated in particular and preferred embodiments by reference to the accompanyin~ drawings in which:
E`igure 1 :is a vertical c~oss-sectional v:iew showin~J
an embodiment of a coupling for a p:ipe in ~ccorc~ance with the presen-t invention, Figure 2 is a ~ertical c~ross-sectional view showing ano-ther emhodiment of a coupling of the invention, Figure 3 is a cross-sectional view showing one embodiment for attachment of the packing material in accordance with the invention, and Figure 4 is a cross-sectional view showing another embodiment for attachment of the packing material in accordance with the invention.
With further reference to the drawings, Figure 1 illustrates the present invention applied to the direct con-nection o end-to-end pipes having pipe ends la and lb. Pipe end la is defined with a male screw 3 and pipe end lb is defined with a female screw ~. The male screw 3 has, at its terminal, a step 5 serving as a stop for the female screw 4. An outer circumferential surface 6 around the step 5 is finished smoothly. An inner circumferential surface 7 at the end portion of the female screw ~ is also finished smoothly.
Step 5 is contacted with an end portion 8 of the female screw 4, to produce a first seal A at the contact zone and between the outer circumferential surface 6 and the inner circumferen-tial surface 7.
An outer circumferential surface 9 at the front end portion of male screw 3 is defined with smooth tapered surface. This smooth tapered surface extends lengthwise and is convexly curved. An inner circumferential surface 10 of the terminal part of the female screw 4 is formed smoothly with a taper corresponding to the taper on outer circvmferen-tial surface 9. Thus, a second seal B is provided by contact 7~
of the outer circumferential surface g and the inner circumferential ~surface 10.
In such a structure, a step 11 is provided at the inner part oE the female screw 4, [nore particularly, at the terminal part of the smooth inner circumferential surface 10, and this step 11 and the front end portion 13 of the male screw 3 are contacted via a pac~ing material 12 and provide a third seal C.
With reference to Figure 2 there is shown one embodiment of the present invention applied to a coupling structure using a sleeve 2. Sleeve 2 has female screws 4 and 4 formed in length at the both sides of an inner surface. A
central portion thereof is defined by a convex portion 14 both sides of which serve as stops 11. Each of ends la and lb of the pipes is defined with a male screw 3. The outer circumferential surface 9 on the front end part of each male screw 3 is finished smoothly with a taper. The smooth surface is formed lengthwise with a convex curvature. The inner circumferential surface 10 at the terminal part of each female screws4 is finished smoothly with a taper correspondin~g ~o the taper of the outer circumferential surface 9. A seal B is formed by contact between the outer circumferential surface 9 and the inner circumferential surface 10.
Seals C are formed by contact between the respective steps 11 and the front ends 13 of the male screws 3 via the packing material 12.
Figures 3 and 4 each show a manner of attaching the packing material 12. In each case, a concave groove 15 is formed for holding the packing material 12 of R in cross-section. The packing material 12 is fixed by means of baking, ~:~l3.~
adhesive agent or the l.ike to the concave groove .L5 and thestep 11 at its outer circumference and outer side Eace. In each of F'igure 3 and ~, the step 11 is formed wi~h an obli-quity ~1 towarcl the male screw portion with respect to a vertical line thereof, i.e. the side wall of step 11 is disposed at an obli~ue angle with respect to the vertical, and - the packing material 12 is also formed with an obliquity corresponding to the obliquity l In addition to such a structure, the packing material 12 in Figure 4 is formed on the other side with an obliquity in correspondence to which obliquity ~2 is provided at the end 13 of the male screw. Due to the step 11, the side face of the packing material 12, and the obliquity at the front end 13 of the ma:Le screw portion, the packing material 12 is prevented from protrusion or dropping toward the i.nterior of the pipe. It is preferable that -the above oblique angle be not more than 20o As the packing material, there rnay be used, for example rubber, Teflon (trade mark), organic substances, for example synthetic resins including fluorine synthetic resins, 20 and metals whose elastic coefficient is lower than that of the pipe or the sleeve.
The present invention can be applied to a coupling joint in which the outer circumferential surface of the male : screw is straight in an axial direction.
Depending upon the coupling structure of the inven-tion, the seals A and B are formed as shown in Figure 1 and the seal A is formed as shown in Figure 2 by screwing the male screw 3 into the female screw 4. Further, the seal C is formed between the end portion 13 and the packing material 12 which is compressed by pressing the end portion 13 so that the sealing effect is as a whole increased.
Furthermoxe, in the structure where the stopping 5 tep is provided at the end of the pipe 'hav.ing the rn~le screw, the pac~ing material 12 closes the clearance between the front end portion of t'he male screw and the term.inal portion of the female screw, so that corrosion in this clearance is avoided.
Since the clearance is su'bstantially eliminated, and when the coupling is used as a casing pipe, damage can be prevented which is caused by the end portion of the female screw being caught by the drill pipe or the tubing pipe moving within the casing pipe.
With respect to the coupling joint having the struc-ture provided with the step in the female screws4 as shown in Figure 2, since the male screws 3 are screwed in the female screws 4 while compressing the packing material 12 until the outer circumfexential surface 9 at the front end part of each mal.e screw 3 closely contacts the inner circumferential surface 10 of the female screw, a proper seal B may be provided even if the sizing tolerances are large.
Thus, the present inventi.on may be applied to both a coupling structure which directly makes an end-to-end connection of the pipes and forms the stopping step at the inner part of the female screw, or to the coupling structure which uses a sleeve and forms a stopping step on the outer circumferential surface in the vicinity of the terminal part of the male screw, and to the other forms of the couplings.
q'hi5 lr~ver~tion relates to a screw coup]ing joirl~, more especially to a screw coupliny joint Eor rnakirlq erld-to end connections between pipes for an oil or gas well.
Casing pipes or tubing pipes Eor oil or gas wells which cornprise a plurality of pipe elements connec-ted -to each other at a large depth of -the earth. For satisfactory use in service, -the couplin~ portion is re~uired to have sufficient strength and sealing ability. In one conventional structure of coupling joint, the pipe is defined with a male screw on one end thereof and with a female screw on the o-ther end, and is provided with a step which forms a stop on an outer circumferential surface about the -terminal part of the rnale screw portion. The outer circumference surface on the front end portion of the male screw and the inner circumferential surface oE the female screw are provided with smooth tapered faces. ~nder a condition in which the pipes of such structure are connected at the ends, the front end portion of the female screw contacts the step so -that a seal is forrned, and the smooth face of -the outer circumferential surface at the front end portion of the male screw is contacted with the smooth face of the inner circumferential surface of the female screw so that another seal is formed. In such a structure having the stop at the male screw, if the female screw contacts the stop of the male screw, the male screw cannot be further advanced. Therefore, in order to provide proper sealing between the smooth surface of the male screw and the smooth surface of the female screw, the diameters of those smooth surfaces need to be determined within severe production tolerances.
In the case of a coupling joint using a sleeve, generally a female screw is formed on the sleeve, and a male :~Lq~
screw i~ formed about an end of the pipe, arld a step :i5 formed on the interior of the sleeve to serve as a stop.
Tapered smooth faces are provided on the outer circumferential surface on the front end of the male screw and the inner circumferential surface of the interior of the female screw.
In this structure, when the front end portion of the male screw contacts the step, the seal is made between the smooth surface of the male screw and the smooth surface of the female screw. If the male screw contacts the step of the sleeve at its end point, a further screwing cannot be effected.
Therefore severe production tolerances are required here as mentioned above.
If the taper of the smooth surface is 1/16 and if the diameter of the pipe changes O.lmm, the position of the end portion of the female screw or the male screw changes as much as 1.6mm in length of the pipe, and the production tolerance is so severe that it is difficul-t to form a stab]e seal.
Further, the abo~e mentioned coupling joint has difficulties as more particularly indicated hereinafter.
In the structure of the former coupling joint, a clearance is made between the front end portion of the male screw and the terminal portion of the female screw, as a consequence eddy currents of fluid develop in this clearance and corrosion occurs there. If a casing pipe were substituted for such structure, the tubing pipe or the drill pipe to be served within the casing pipe would be caught, due to the clearance, at the front end portion of the male screw, and damage would occur.
In the structure of the latter coupling joint, since the front end portion of the male screw and the step portion of the female screw contact each other within the coupling joint, there OCC-lrS the disadvallt~lcJe that corroslon resi3tant coating thereon comes o~f due to the metal-to--metal contact.
~ he present invention seeks to provide an irnprovement in this kind of coupling joint, ancl to overcome the disadvan-tages mentioned above.
The invention seeks to provide a coupling structure which may form a satisfactory seal without requiring severe production tolerances.
The invention also seeks to provide a coupling structure which may prevent corrosion within the pipe at the connection of the coupling joint, in which the front end portion of the female screw contacts the step portion on the outer circumfexential surface about the terminal part of the male screw.
The invention furtner seeks to provide a coupling structure which may prevent damage at the inner wall of the coupling of the type mentioned above, when a tubing pipe or the drill pipe is served therein.
Still further the invention seeks to provide a coupling structure which may form the required seal between the outer circumference of the smooth surface at the front end portion of the male screw portion and the inner circum-ference of the smooth surface at the inner part of the female screw portion, even though the production tolerance is large in a coupling joint in which the end portion of the male screw contacts a step portion at the inner part of -the *emale screw.
The invention also seeks to provide a coupling structure which may avoid damage or exfoliation of ~ corrosion resistant coating.
'7~
In accordance with the invention there iB provid~d a screw coupling joint for a pipe to be used in an oil or ~as well, in which plpes are directly contacte~ end-to-end or via a sleeve, comprising a fernale screw having a step at an inner part thereof for contact with a front end portion of a male screw via a packing material to provide a first and a second seal formed between the front end portion of the male screw and the packing material.
In particular the invention provides a screw coupling joint for end~to-end connections between pipes for oil or gas wells comprising a female screw means and a male screw means adapted to engage the female screw means to form said joint, said female screw means having a step defined in an inner surface of an inner part, and said male screw means having a first end, and a packing material between said front end and said step.
In the case of a coupling joint in which the front end portion of the female screw contacts a step defined on the outer circumference about the terminal of the male screw, the pac~cing material closes the clearance between the front end portion of the male screw and the terminal part of the female screw.
By contacting the front end portion of the male screw to the step on the inner circumferential surface at the inner part of the female screw, the production tolerances are absorbed by compression of the packing material, and metal-to-metal contact is avoided between the front end portion of the male screw and the step at the inner part of the female screw.
The invention is illustrated in particular and preferred embodiments by reference to the accompanyin~ drawings in which:
E`igure 1 :is a vertical c~oss-sectional v:iew showin~J
an embodiment of a coupling for a p:ipe in ~ccorc~ance with the presen-t invention, Figure 2 is a ~ertical c~ross-sectional view showing ano-ther emhodiment of a coupling of the invention, Figure 3 is a cross-sectional view showing one embodiment for attachment of the packing material in accordance with the invention, and Figure 4 is a cross-sectional view showing another embodiment for attachment of the packing material in accordance with the invention.
With further reference to the drawings, Figure 1 illustrates the present invention applied to the direct con-nection o end-to-end pipes having pipe ends la and lb. Pipe end la is defined with a male screw 3 and pipe end lb is defined with a female screw ~. The male screw 3 has, at its terminal, a step 5 serving as a stop for the female screw 4. An outer circumferential surface 6 around the step 5 is finished smoothly. An inner circumferential surface 7 at the end portion of the female screw ~ is also finished smoothly.
Step 5 is contacted with an end portion 8 of the female screw 4, to produce a first seal A at the contact zone and between the outer circumferential surface 6 and the inner circumferen-tial surface 7.
An outer circumferential surface 9 at the front end portion of male screw 3 is defined with smooth tapered surface. This smooth tapered surface extends lengthwise and is convexly curved. An inner circumferential surface 10 of the terminal part of the female screw 4 is formed smoothly with a taper corresponding to the taper on outer circvmferen-tial surface 9. Thus, a second seal B is provided by contact 7~
of the outer circumferential surface g and the inner circumferential ~surface 10.
In such a structure, a step 11 is provided at the inner part oE the female screw 4, [nore particularly, at the terminal part of the smooth inner circumferential surface 10, and this step 11 and the front end portion 13 of the male screw 3 are contacted via a pac~ing material 12 and provide a third seal C.
With reference to Figure 2 there is shown one embodiment of the present invention applied to a coupling structure using a sleeve 2. Sleeve 2 has female screws 4 and 4 formed in length at the both sides of an inner surface. A
central portion thereof is defined by a convex portion 14 both sides of which serve as stops 11. Each of ends la and lb of the pipes is defined with a male screw 3. The outer circumferential surface 9 on the front end part of each male screw 3 is finished smoothly with a taper. The smooth surface is formed lengthwise with a convex curvature. The inner circumferential surface 10 at the terminal part of each female screws4 is finished smoothly with a taper correspondin~g ~o the taper of the outer circumferential surface 9. A seal B is formed by contact between the outer circumferential surface 9 and the inner circumferential surface 10.
Seals C are formed by contact between the respective steps 11 and the front ends 13 of the male screws 3 via the packing material 12.
Figures 3 and 4 each show a manner of attaching the packing material 12. In each case, a concave groove 15 is formed for holding the packing material 12 of R in cross-section. The packing material 12 is fixed by means of baking, ~:~l3.~
adhesive agent or the l.ike to the concave groove .L5 and thestep 11 at its outer circumference and outer side Eace. In each of F'igure 3 and ~, the step 11 is formed wi~h an obli-quity ~1 towarcl the male screw portion with respect to a vertical line thereof, i.e. the side wall of step 11 is disposed at an obli~ue angle with respect to the vertical, and - the packing material 12 is also formed with an obliquity corresponding to the obliquity l In addition to such a structure, the packing material 12 in Figure 4 is formed on the other side with an obliquity in correspondence to which obliquity ~2 is provided at the end 13 of the male screw. Due to the step 11, the side face of the packing material 12, and the obliquity at the front end 13 of the ma:Le screw portion, the packing material 12 is prevented from protrusion or dropping toward the i.nterior of the pipe. It is preferable that -the above oblique angle be not more than 20o As the packing material, there rnay be used, for example rubber, Teflon (trade mark), organic substances, for example synthetic resins including fluorine synthetic resins, 20 and metals whose elastic coefficient is lower than that of the pipe or the sleeve.
The present invention can be applied to a coupling joint in which the outer circumferential surface of the male : screw is straight in an axial direction.
Depending upon the coupling structure of the inven-tion, the seals A and B are formed as shown in Figure 1 and the seal A is formed as shown in Figure 2 by screwing the male screw 3 into the female screw 4. Further, the seal C is formed between the end portion 13 and the packing material 12 which is compressed by pressing the end portion 13 so that the sealing effect is as a whole increased.
Furthermoxe, in the structure where the stopping 5 tep is provided at the end of the pipe 'hav.ing the rn~le screw, the pac~ing material 12 closes the clearance between the front end portion of t'he male screw and the term.inal portion of the female screw, so that corrosion in this clearance is avoided.
Since the clearance is su'bstantially eliminated, and when the coupling is used as a casing pipe, damage can be prevented which is caused by the end portion of the female screw being caught by the drill pipe or the tubing pipe moving within the casing pipe.
With respect to the coupling joint having the struc-ture provided with the step in the female screws4 as shown in Figure 2, since the male screws 3 are screwed in the female screws 4 while compressing the packing material 12 until the outer circumfexential surface 9 at the front end part of each mal.e screw 3 closely contacts the inner circumferential surface 10 of the female screw, a proper seal B may be provided even if the sizing tolerances are large.
Thus, the present inventi.on may be applied to both a coupling structure which directly makes an end-to-end connection of the pipes and forms the stopping step at the inner part of the female screw, or to the coupling structure which uses a sleeve and forms a stopping step on the outer circumferential surface in the vicinity of the terminal part of the male screw, and to the other forms of the couplings.
Claims (15)
1. A screw coupling joint for end-to-end connections between pipes for oil or gas wells, comprising:
a female screw and a male screw, a step defined in an inner circumference at an inner part of said female screw, said male screw having a front end portion adapted to cooperate with the step via a packing material, a first seal produced between a smooth outer circumferential surface of the male screw and a smooth inner circumferential surface of the female screw, a second seal produced between a smooth surface of the male screw adjacent said front end portion, said smooth surface being axially convexly tapered, and an inner circumferential surface of the female screw, and a third seal produced between said step and said front end portion with zero clearance therebetween.
a female screw and a male screw, a step defined in an inner circumference at an inner part of said female screw, said male screw having a front end portion adapted to cooperate with the step via a packing material, a first seal produced between a smooth outer circumferential surface of the male screw and a smooth inner circumferential surface of the female screw, a second seal produced between a smooth surface of the male screw adjacent said front end portion, said smooth surface being axially convexly tapered, and an inner circumferential surface of the female screw, and a third seal produced between said step and said front end portion with zero clearance therebetween.
2. A screw coupling joint according to claim 1, wherein said male screw is defined in a pipe end of a first pipe and said female screw is defined in an opposed pipe end of a second pipe.
3. A screw coupling joint as claimed in claim 1, wherein said step has a side which is oblique with respect to a vertical line towards the male screw, and said packing material has an oblique side adapted to fit the step oblique side.
4. A screw coupling joint as claimed in claim 3, wherein the step comprises a concave groove at an inner circumferential surface of said female screw adapted for securing the packing material.
5. A screw coupling joint as claimed in claim 3, wherein said front end portion is oblique toward the outside, and the packing material has an oblique side in opposition to the oblique front end portion.
6. A screw coupling joint as claimed in claim 3, wherein the front end of the male screw and a front end facing side of the packing material are vertical.
7. A screw coupling joint as claimed in claim 3, 4 or 5, wherein the packing material is of an organic substance.
5. A screw coupling joint for end-to-end connections between pipes for oil or gas wells comprising a female screw means and a male screw means adapted to engage the female screw means to form said joint, said female screw means having a step defined in an inner surface of an inner part, and said male screw means having a front end, and a packing material between said front end and said step, a first seal defined between a smooth outer surface of the male screw means remote from said front end, and a smooth inner surface of the female screw remote from said step, a second seal defined between a smooth outer surface of the male screw means, adjacent said front end, and a smooth inner surface of the female screw means adjacent said step, said smooth cuter surface adjacent said front end being axially convexly curved towards said front end, and a third seal defined with said packing material between said step and said front end, with zero clearance therebetween.
9. A screw coupling joint as claimed in claim 8, wherein the step has a side which is oblique with respect to a vertical line towards the male screw means, and the packing material has an oblique side adapted to fit the step oblique side.
10. A screw coupling joint as claimed in claim 97 wherein the step comprises a concave groove at an inner circumferential surface of said female screw means, said concave groove being adapted for securing the packing material.
11. A screw coupling joint as claimed in claim 9 wherein said front end is oblique toward the outside and the packing material has an oblique side in opposition to the oblique front end.
12. A screw coupling joint as claimed in claim 9, wherein said front end of the male screw means and a front end facing side of the packing material are vertically disposed.
13. A screw coupling joint as claimed in claim 9, 10 or 11 wherein the packing material is of an organic substance.
14. A screw coupling joint as claimed in claim 8, 9 or 10 wherein said male screw means comprises first and second male screws defined in opposed ends of first and second pipes and said female screw means comprises first and second female screws defined in a sleeve adapted to engage said opposed first and second pipe ends.
15. A screw coupling joint as claimed in claim 8, 9 or 10 wherein said male screw means comprises first and second male screws defined in opposed ends of first and second pipes and said female screw means comprises first and second female screws defined in a sleeve adapted to engage said opposed first and second pipe ends, and the packing material is of a metal whose elastic coefficient is not more than the composing material of said sleeve.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP39,513 | 1982-03-23 | ||
| JP1982039513U JPS58142475U (en) | 1982-03-23 | 1982-03-23 | Threaded joints for oil country pipes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1191172A true CA1191172A (en) | 1985-07-30 |
Family
ID=12555120
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000403231A Expired CA1191172A (en) | 1982-03-23 | 1982-05-18 | Screw coupling joint |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS58142475U (en) |
| CA (1) | CA1191172A (en) |
| GB (2) | GB2117469B (en) |
| NL (1) | NL8202098A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4624488A (en) * | 1983-12-16 | 1986-11-25 | Hydril Company | Tubular connection |
| JPS616488A (en) * | 1984-06-20 | 1986-01-13 | 日本鋼管株式会社 | Screw coupling for oil well pipe |
| JPH081352Y2 (en) * | 1990-10-11 | 1996-01-17 | 新日本製鐵株式会社 | Steel pipe fittings |
| GB9226489D0 (en) * | 1992-12-19 | 1993-02-10 | Univ Manchester | A joint |
| US6176524B1 (en) * | 1995-08-19 | 2001-01-23 | Nippon Steel Corporation | Oil well pipe threaded joint |
| US5855397A (en) * | 1997-04-02 | 1999-01-05 | Cummins Engine Company, Inc. | High-pressure sealable connector for a pressure sensor |
| FR2776746B1 (en) * | 1998-03-26 | 2000-04-28 | Vallourec Mannesmann Oil & Gas | THREADED ASSEMBLY OF METAL TUBES FOR CONTAINING A FLUID |
| FR2800150B1 (en) * | 1999-10-21 | 2001-12-07 | Vallourec Mannesmann Oil & Gas | EXTERNAL PRESSURE THREADED TUBULAR JOINT |
| JP5936151B2 (en) * | 2014-03-19 | 2016-06-15 | 日本管洗工業株式会社 | Method for manufacturing pressure pipe connection structure |
| US20230341070A1 (en) * | 2020-11-06 | 2023-10-26 | Swagelok Company | Tapered thread connection sealing arrangements |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB392827A (en) * | 1932-10-26 | 1933-05-25 | Gustavus Alfred Montgomery | Drill stem and coupling therefor |
| US3572777A (en) * | 1969-05-05 | 1971-03-30 | Armco Steel Corp | Multiple seal, double shoulder joint for tubular products |
| JPS5211767B2 (en) * | 1972-03-31 | 1977-04-02 | ||
| JPS5211765B2 (en) * | 1972-03-31 | 1977-04-02 | ||
| US3989284A (en) * | 1975-04-23 | 1976-11-02 | Hydril Company | Tubular connection |
| GB1521133A (en) * | 1975-05-22 | 1978-08-16 | British Petroleum Co | Screw threaded connector for tubular members |
| US4296954A (en) * | 1978-09-14 | 1981-10-27 | Sekisui Kagaku Kogyo Kabushiki Kaisha | Pipe coupling and pipe joint connection |
| DE3372517D1 (en) * | 1982-05-19 | 1987-08-20 | Kenneth J Carstensen | Coupling for tubing or casing and method of assembly |
| US4458925A (en) * | 1983-05-19 | 1984-07-10 | Otis Engineering Corporation | Pipe joint |
-
1982
- 1982-03-23 JP JP1982039513U patent/JPS58142475U/en active Pending
- 1982-05-12 GB GB08213769A patent/GB2117469B/en not_active Expired
- 1982-05-18 CA CA000403231A patent/CA1191172A/en not_active Expired
- 1982-05-21 NL NL8202098A patent/NL8202098A/en not_active Application Discontinuation
-
1985
- 1985-08-21 GB GB08520982A patent/GB2162607B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2162607B (en) | 1986-09-24 |
| GB8520982D0 (en) | 1985-09-25 |
| NL8202098A (en) | 1983-10-17 |
| JPS58142475U (en) | 1983-09-26 |
| GB2117469B (en) | 1986-09-03 |
| GB2117469A (en) | 1983-10-12 |
| GB2162607A (en) | 1986-02-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |