JPH0233835B2 - - Google Patents

Description

Claim 1 The male threaded portion or female threaded portion of the metal tube and the annular joining support surface forming the abutting portion for ensuring liquid tightness of the threaded portions of the metal tubes screwed together. It includes a ring made of plastic material which is screwed onto the threaded part of the joining area of the metal tube for protection before use, which ring 6, 25, 42, 56 has at least several turns of the threaded part 7, 26, 43, 57, and the metal tubes 1, 19, 3 are connected through this threaded portion.
Threaded portions 3, 21, 40, 5 of joint areas 9, 54
In the protection device adapted to be screwed onto the annular abutment area 8, 27, 47,
62 and in this abutment area is located facing the joint support surface which forms the abutment 4, 22, 41, 66 of the metal tube when the ring is screwed to the bottom into the metal tube. The front face 9, 28, with dimensions such that
49, 64 are provided, and on the inner edge of this front surface, inner edges 4A, 22 of the joining support surface forming the abutting surface of the metal tube are provided.
An annular first liquid-tight part 10, 29, 48, 63 is provided which comes into contact with the vicinity of A, 50, 65 to ensure liquid-tightness, and the front surface is connected to the joint support forming an abutting part. A protection device characterized in that it has a cross-sectional shape such that an annular closed space 11, 30, 52, 67 is formed between a surface and the front surface facing the same.

2 The above-mentioned annular first liquid-tight portion 10, 29, 4
8, 63 are constituted by lips facing inward of the metal tube, and when the ring is screwed to the bottom, the lips meet the abutting portions 4, 22, 41,
The inner edge 4A of the joint support surface forming 66,
22A, 50, 65, and the outer edges 10A, 29 of the lip.
The wall 4B, 2 of the metal tube in the area where A, 63A connects the inner edge and the inner wall surface of the metal tube.
3. The protective device according to claim 1, wherein the protective device faces 3,66A.

3 Outer edge 10 of the lip 10, 29, 63
A, 29A, 63A and the joint support surface 4, 22,
66 and the facing part of the front surface, the inner edge 4A, 22A, 65 is in contact with the front surface 9, 28, 64 of the abutment area of the ring. A protective device according to claim 2.

4 The rings 6, 25, 42, and 56 have an annular second liquid-tight portion that comes into contact with the metal tube near one end of the threaded portion when the ring is screwed into the metal tube, and the abutting portion is 4. The protection device according to claim 1, wherein the joint support surface formed is located near the other end of the threaded portion.

5 The joint support surface 4, 22, 41, 66 and/or the male threaded portion or the female threaded portion are truncated conical, and the annular closed space 11, 30, 52, 6
5. The protection device according to claim 1, wherein at least a part of the protection device 7 is filled with a protection fluid such as grease.

6 Metal sleeves 51, 6 are attached to the main part of the non-threaded surfaces of the rings 42, 56.
8. The protective device according to claim 1, wherein the protective device is coated.

7. Claims 1 to 6, characterized in that the rear end of the ring and/or the metal sleeve extends beyond the end of the metal tube.
A protective device according to any one of paragraphs.

8 At the rear end of the ring or metal sleeve, gripping parts 16, 17, 36, 37, 71, which can be gripped by a screwing or removal tool,
7. The protective device according to any one of claims 1 to 7, characterized in that: 72 is formed.

9. Protection according to any one of claims 1 to 8, characterized in that the through-hole of the ring is closed by a fixed or removable liquid-tight circular bottom. Device.

10. A protective device according to any one of claims 1 to 9, characterized in that the ring is made of polyurethane, polyamide or polyethylene.

11 Screwed into the threaded part of the joint area of the metal pipe,
Plastic for a protective device that protects the male threaded part or female threaded part of a metal tube and the annular joining support surface that forms an abutment part to ensure liquid tightness of the threaded parts of the metal tubes screwed together. In the ring made of material, the ring has threaded parts 3, 21, 40,
55, a threaded portion with at least several turns engageable with
It has an annular contact area 8, 27, 47, 62, and an annular first liquid is provided at the inner edge of the front surface 9, 28, 49, 64 of the annular contact area 8, 27, 47, 62. Closed portions 10, 29, 48, 63 are provided, and the contact area connects the ring to metal tubes 1, 19,
The inner edge portions 4A, 22A of the joint support surfaces 4, 22, 41, 66, where the first liquid-tight portion forms an abutting portion of the metal tube when screwed to the bottom of the threaded portion of the metal tube 39, 54; , 50, 65 in a fluid-tight manner, and an annular closed space 11, 30, 52, 67 is formed between the joint support surface and the front surface. A distinctive ring.

12. Ring according to claim 11, characterized in that the main part of the unthreaded surface of the ring is covered with a metal sleeve (51, 68).

13. The ring according to claim 11 or 12, characterized in that the ring is made of polyurethane, polyamide or polyethylene.

Specification The apparatus of the present invention is concerned with protecting the joining support surface forming the threaded part and abutting part of metal pipes before use, thereby threading the metal pipes together and making the joint part liquid-tight. This is to ensure the sex. The device of the invention relates to threaded parts of metal tubes that are joined directly to each other or via threaded joints or sleeves.

The apparatus of the invention is particularly suitable for drilling oil wells,
This invention relates to the protection of joint support surfaces and threaded portions that form the abutting portions of tubes used in tubing or casing.

Among the various types of threaded joints that have already been developed, the one described in French Patent No. 1,489,013 is particularly known. The joint support surface forming the abutment surface to ensure fluid-tightness of the joint described in this patent has a concave frustoconical annular surface machined into the externally threaded end of the tube; The annular surface abuts a convex frustoconical annular surface machined near the externally threaded inner end.

The fluid-tightness of a joint depends on the quality of the joint bearing surfaces forming the threads and abutments, but is not susceptible to damage, for example by impact during transport, or especially by contact with sewage or other aggressive media. There is a risk of damage due to corrosion.

Various devices have been proposed to protect threaded tube joints.

German patent application DE-OS 2834489 describes a protective cap of elastomeric or plastic material covering the external thread of a tube.
An inner relief section substantially parallel to the tube axis ensures seating of the cap on the thread. This device can also be applied to protect internal threads.

However, this device is not intended to protect bonded support surfaces, is not liquid tight, and therefore does not provide protection against corrosion.

West German utility model application no. DC-GBM No. 78004849 discloses a protective member for a male or female frustoconical thread at the end of a steel pipe, made of a flexible material to which a steel tubular reinforcing member is joined. has been done. The protective member made of a flexible material includes a truncated conical thread that engages with the thread of the steel pipe, and two liquid-tight areas,
One area abuts the forward end of the steel pipe.

In such devices, for example, French patent no.
It is not possible to effectively protect a mating support surface forming an abutment, such as the frustoconical support surface disclosed in No. 1489013. Additionally, it is difficult to precisely thread flexible materials and it is difficult to achieve a fluid-tight abutment of the joint at the abutment. moreover,
It is not sufficient to provide protection with impact-flexible materials in areas not covered by reinforcing material.

British Patent Application No. 2093426 discloses a protective cap for the external threads of a tube. This protective cap comprises an outer case, preferably made of steel, and an inner wall, preferably of impact-resistant plastic material. The inner wall is threaded for threading onto the end of the tube. The end edge of the tube is protected by the overlying rounded edge of the cap.

However, this device is not designed to protect mating support surfaces forming an abutment, such as frustoconical support surfaces, from corrosion. This device does not even provide any means to ensure protection against corrosion of the area covered by the cap. Therefore,
This device does not apply to the protection of internal threads of pipes.

The possibility of creating a device that can effectively protect the joint support surface that forms the threaded part and abutting part of metal pipes from corrosion and impact before use is being pursued. It had been. In particular, the possibility of protecting the threaded bearing surfaces forming the inner and outer threads and abutments, as described for example in French Patent No. 1 489 013, has been sought.

Furthermore, the possibility of keeping the mating support surfaces forming the abutments in contact with a certain amount of protective fluid was pursued.

Finally, the possibility of creating a protection device against shocks and vibrations that can be installed and removed and, if necessary, tools or jigs can be passed freely inside the metal tube without disassembly, is explored. It was done.

According to the protection device for the threaded portion of a metal tube, which is an object of the present invention, the above problems can be easily and effectively solved. The device of the invention relates to a device for protecting joint support surfaces of threaded parts and abutment parts of metal tubes, and in particular to protection of joint support surfaces forming a butt part with a frustoconical surface as described in French Patent No. 1,489,013.

The device of the invention comprises a rigid plastic tube having a threaded portion for threaded connection to a male or female threaded portion of a joining area with a joining support surface forming an abutment of a metal tube or cylindrical joining member. Equipped with a ring made of The ring further includes an annular abutment area;
The contact area has a front surface such that when the ring is screwed into the metal tube all the way to the bottom, it lies opposite the mating support surface forming the abutment of the metal tube.

The inner edge of the front surface is provided with an annular first liquid-tight means that cooperates with a joining support surface forming the abutting portion of the metal tube and the inner edge to ensure liquid-tightness. . In consideration of the shape of the joint support surface of the tube, the front surface includes a joint support surface forming the abutting portion;
The shape is such that an annular closed space is formed between it and the facing front surface.

Furthermore, it is preferred that this annular closed space is at least partially filled with a fluid that protects the joints, such as grease, and is particularly corrosion-resistant.

The ring further comprises a first annular liquid-tight means operatively associated with the first liquid-tight means. This second
The liquid-tight means is such that when the ring is screwed to the bottom, the joining support surface forming the abutting portion is located near the end of the threaded portion of the metal tube opposite to the end of the ring located in the vicinity thereof. be arranged to be located.
Preferably, the first liquid tight means is a lip formed by the inner edge of the front face of the ring. The second fluid-tight means is also formed by an annular lip integral with the ring;
Its shape is such that when the ring is screwed all the way to the bottom,
It is configured to be in liquid-tight contact with the pipe wall. This second liquid-tight means may be a fitted fitting, such as an O-ring provided in an annular receptacle within the ring.

The ring may have several turns of the ring in the area facing the threaded part of the metal tube when the ring is screwed to the bottom, and may be smooth elsewhere.

Preferably, the ring further has a rear portion that extends beyond the tube end when screwed to the bottom. A gripping portion such as a relief portion is formed in this area to facilitate gripping of a tool for screwing or unscrewing. This relief is preferably parallel to the tube axis and is arranged on the inner and outer walls of the ring.

To increase the impact strength of the ring, its unthreaded surface is provided with an integral metal sleeve. The sleeve may extend beyond the end of the plastic ring in a direction opposite the metal tube. At this time, this sleeve has
It is possible to provide an area with gripping means to facilitate gripping of a tool for screwing or unscrewing.

The inner diameter of the plastic ring, whether covered by a metal sleeve or not, is such that it allows the insertion of a tool or jig without drawing out the protective fluid. Conversely, in certain applications, the protective fluid is sealed off by a liquid-tight circular bottom integral with a plastic ring or sleeve. This bottom may be removable.

For manufacturing the ring, it is preferred to use plastic materials with good strength and elasticity, such as polyurethane-based materials. In particular, when a metal sleeve is not used, it is preferable to use a plastic material that has excellent impact resistance, especially at low temperatures. For example, it is preferred to use modified polyamides or certain polyethylenes with improved impact resistance.

The metal sleeve covering the ring may be made of any suitable metal or alloy, such as common steel, alloy steel, or stainless steel.

The device of the invention is particularly preferably used for the protection of joint areas of metal tubes with external or internal threads of frustoconical shape. The ring then has a corresponding thread, preferably limited to several turns. In this way, it is easy to center the ring before screwing, avoid clogging of the screw due to overlapping threaded parts, and reduce screwing or unscrewing time. Finally, the invention relates to a ring which is itself made of plastic material, coated with a metal sleeve or not, from which the device according to the invention can be made.

The following description and the accompanying drawings do not limit the scope of the invention, but they provide a clearer understanding of the main features of the protection device of the invention and of the supplementary features of the embodiments of the device of the invention. You can do it.

1 is an axial half-sectional view of a protection device according to the invention comprising a ring of plastic material screwed onto the male threaded end of a metal tube; FIG.

FIG. 2 shows the arrangement of the liquid-tight means of FIG. 2 in a ring made of plastic material. FIG. 2 is a partially enlarged view of FIG. 1;

FIG. 3 is an axial half-sectional view of a protection device according to the invention comprising a ring of plastic material screwed onto the female threaded end of a metal tube.

FIG. 4 is an axial half-sectional view of a protective device according to the invention comprising a ring made of plastic material screwed onto the external thread of a metal tube and covered by a metal sleeve.

FIG. 5 is an axial half-section of a protective device according to the invention comprising a ring made of plastic material screwed onto the female threaded end of a metal tube and covered by a metal sleeve.

6 is an end view in the direction of arrow F of the portion beyond the metal sleeve of FIG. 5; FIG.

As shown in the _axial cross-sectional view of half of _FIG .
Its externally threaded joint area 2 is protected by the device of the invention. This joint area 2 has an outer frustoconical thread 3 and a joint support surface 4 forming an abutment whose generatrix is inclined at an angle of approximately 15 to 25° to the axis X ₁ -X ₂ . It is equipped with The support surface 4 is connected to the end of the thread 3 via a beveled surface 5 .

The device of the invention comprises a single block ring 6 made of plastic material with an internal thread 7. This ring 6 has only a few threads and is screwed to the bottom into the thread of the tube until it butts and tightens. The abutment area 8 of the ring has an annular front area or front face 9 facing the joint support surface 4 . The inner edge of this front section is provided with an annular first liquid-tight means consisting of a lip 10. This lip 10 seats fluid-tightly on the support surface near the inner edge 4A of the mating support surface when the ring is tightened onto the tube. It is noted that in the embodiment of the invention shown in FIG. Should.

In this way, the outer edge 10A of the lip 10
faces the inner surface of the tube in the joint area 4B at the inner edge 4A of the joint support surface 4 when the ring is screwed to the bottom. In this state, the inner edge 4A
rests on the front face 9 in the joint area between the outer edge 10A of the lip 10 and the front area or part of the front facing the joint support surface 4.
An annular closed space 11 remains between this front surface and this joint support surface. This space, which in the illustrated example has a generally triangular cross-section, is preferably filled with a protective fluid, such as grease. Due to the particular arrangement of the lip 10 as shown, the joint support surface 4 is protected over its entire surface by a protective fluid held in an annular closed space 11. In addition, lip 1
The front part of 0 forms a kind of labyrinth towards the inside of the tube in a direction approximately parallel to the axis. The inner edge 4A of the support surface 4 and the front surface 9 of the abutment area 8 of the ring 6
This labyrinth limits the escape of the protective fluid in the event of a breach in the fluid tightness at the point of contact between.

In order to improve the fluid-tightness of this enclosed space and to protect the threaded area, the ring may be provided with second fluid-tight means. This second liquid-tight means is located beyond the threaded area 3 with respect to the joint support surface 4. This second liquid-tight means is shown enlarged in FIG. 2, which is a detailed view of FIG. In FIG. 2, the introduction area 12 of the ring 6 around the tube 1 is shown. As shown in FIG.
are arranged radially in the direction of the axis X ₁ -X ₂ . Lip 14 is seated on the outer wall of the tube to form a second liquid tight means. This lip is sized so that when the ring is screwed to the bottom, it seats resiliently and fluid-tightly on the outer wall of the tube. In this way, the ingress of corrosive fluids between the ring and the tube in the direction of the threaded part 3 and the closed space 11 is prevented.
The minimum inner diameter of the ring D ₁ is the inner diameter of the tube in the normal part D ₂
Larger so tools or jigs can be passed through. Area 15 beyond the tube end of the ring
is provided with relief portions as shown at 16 and 17 on its outer and inner walls, respectively. These relief portions are approximately parallel to the axis and serve as gripping portions for the tool during screwing and unscrewing. The thickness of the ring is sufficient to withstand shocks from handling the tube and to effectively protect the end area of the tube. Similarly, an inner thickness 18 is provided in the vicinity of the introduction area 12 of the ring;
This part is subjected to large stresses and shocks. This thick portion can particularly reduce the impact perpendicular to the axis X ₁ -X ₂ .

FIG. 3 shows a half sectional view of a protective device according to the invention placed on the end of a metal tube 19, which is a body of rotation about the axis X ₃ -X ₄ , for protecting the internally threaded joint area 20. be. This area comprises a frustoconical internal thread 21 and a concave frustoconical support surface 22 forming an abutment. The tube may further include a fitting or a sleeve for assembly with the tube, which includes a joining area with a frustoconical external thread.

The generatrix of the joint support surface 22 is inclined at an angle of 15 to 25 degrees with respect to a plane perpendicular to the axis X ₃ -X ₄ . This joint support surface connects via a beveled surface 24 with the end of the threaded section of the tube.

The protection device comprises a single block ring 25 made of plastic material. This ring has several turns of thread and is screwed to the bottom onto the internal thread of the tube until it snaps into place. Ring abutment area 27
is provided with a front surface 28 that faces the joint support surface 22 .

As in the case shown in FIG. 1, an annular lip 29 oriented inwardly of the tube engages within a circle formed by the inner edge 22A of the mating support surface 22. This inner edge 22A is connected to the support surface 22 and the tube 1.
It is located at the intersection with the inner wall of 9.

When the ring is screwed all the way to the bottom, in the case shown in FIG. It is supported in contact with the front surface 28. The generatrix of this part of the front surface is inclined with respect to the joint support surface to form an annular closed space 30. This enclosed space may be filled with a protective fluid such as grease. Inward lip 29 of tube 19
forms a kind of labyrance to limit the leakage of the protective fluid when the liquid tightness is broken at the point of contact between the inner edge 22A of the mating support surface 22 and the front surface 28, thus limiting the leakage of the protective fluid. Prevent the ingress of corrosive fluids.

In order to supplement the protection, in particular with respect to the threaded part of the tube 20, a second ring is placed between the ring and the end section 31 of the tube, relative to the joint support surface 22, beyond this threaded part.
Liquid-tight means shall be provided. This second liquid-tight means comprises a section 33 of the reinforced rear wall 34 of the ring 25 which seats resiliently and liquid-tightly on the end face 35 of the tube 20.
It consists of an annular lip 32 provided at the top.
The dimensions of the ring 25 are such that when the ring is screwed in to the bottom, a simultaneous liquid-tight contact is obtained with the first and second liquid-tight means. In this way, the threaded portion 21 and the closed space 30 are protected particularly effectively against the ingress of corrosive fluids such as seawater.

The reinforced annular section 34 of the ring protects the end section 31 and end face 35 of the tube from impacts. Relief portions as shown at 36 and 37 are provided on the outer and inner walls of this reinforced area 34, respectively, to enable gripping of the tool during screwing and unscrewing. In the main part, the minimum internal diameter D ₃ of the ring may be smaller than the internal diameter D ₄ of the tube so that it is possible to insert tools or jigs of the usual type.

Figures 4 to 6 show an embodiment of the device according to the invention in which a ring made of plastic material is covered with a metal sleeve to enhance its resistance to impact.

FIG. 4 has a truncated conical external threaded portion 40 and a concave truncated conical joining support surface 41 that forms an abutting portion at the end. Metal tube 3 centered on axis X ₅ X ₆
9 shows a half cross-section of a particular embodiment according to the invention realized around the end of 9; This device comprises a ring 42 made of plastic material with only a few turns of the screw.

Over more than half of the frustoconical bearing surface, the entrance area 44 of this ring is smooth. The ring is shown threaded to the bottom in a tubular manner.

At the forward end of the inlet area 44 of the ring 42, a small annular lip 45 seats on the outer cylindrical wall of the metal tube 39. This small lip constitutes the second liquid-tight means. Furthermore, the ring 42 has an abutment area 47 in which a lip 48 forming the inner edge of its front face 49 rests against the inner edge 50 of the joint support surface 41 . This lip 48 constitutes a first liquid tight means. In this way, an annular closed space 52 is formed between the support surface 41 and the front surface 49.

The outer wall of the ring 42 is covered with a metal sleeve 51. The sleeve 51 extends beyond the end of the ring located beyond the end of the tube and protects the tube from localized impacts. This sleeve may be made of mild steel, for example. Preferably, the connection between the ring and the sleeve is as strong as possible.
For this reason, the sleeve is used as one of the mold walls,
It may also be used to mold rings of plastic material. Furthermore, reliefs and/or recesses may be provided on the inner wall of the sleeve 51, into which the plastic material engages. Other coupling means can be used as well.

FIG. 5 shows a half axial section of a protective device 53 according to the invention, which is equipped with a truncated conical internal thread 55 and is realized at the end of a metal tube 54 centered on the axis of rotation X ₇ X ₈ . Ring 56 made of plastic material
has only a few turns of thread 57 at the large diameter end of the engagement area at the end of the tube 54. An annular lip 5 formed on the rear edge 60 of the ring
9 is supported on the front edge 61 of the tube 54.

An abutment area 62 is formed at the forward end of ring 56 . As shown in FIG. 3, the annular lip 63 is oriented inwardly of the tube 54 and engages within a circle defined by the inner edge 65 of the mating support surface 66 forming the abutment. This inner edge 65 is
It exists at the intersection of the joint support surface 66 of the tube 54 and the inner wall 66A. In the case shown in FIG. 5, when the ring is screwed in to the bottom, the inner edge 65 is attached to the front surface 64 in the connection area between the edge 63A of the lip 63 and the portion of the front surface 64 facing the mating support surface 66. Supported by contact. The generatrix of this front surface is inclined with respect to the generatrix of the joint support surface to form an annular closed space 67.
This closed space 67 may be filled with a protective fluid such as grease. The inward front part of the tube 54 of the lip 63 forms a kind of labyrance, which limits the leakage of the protective fluid, especially if the liquid tightness is compromised at the point of contact between the inner edge 65 and the front face 64. , thus limiting the risk of ingress of corrosive fluids.

The lip 59, which forms a second liquid-tight means, further improves the protection of the entire space between the ring 56 and the tube 54, and in particular prevents moisture from entering and corroding the threads of the tube.

The sleeve 68 is integral with the ring as described above. The radially widened portion 69 is connected via a recess 70 to the portion covered by the ring 56 . This allows the impact received from the outside to be alleviated. As shown in FIG. 6, which is a view of the end of the sleeve in the direction of arrow F,
Two further bosses 71 and 72 are provided on the enlarged portion 69 of the sleeve 68 parallel to the generatrix line, and a relief portion is formed on the inside. With such a configuration,
A rotary tool, only the end 73 of which is shown in cross section, can be introduced into the enlarged part. These bosses 71 and 72 allow the sleeve to be rotated by the rotary tool 73 and the protective device 53 to be attached or removed very quickly.

For certain applications, rings 6, 25, 42 may be
For example, it may have a solid circular wall near its rear end. This circular wall makes it possible to close off the passage through the ring and thus the entrance to the metal tube into which the ring is screwed. If the ring is covered by a metal sleeve 51, 68, this solid circular wall may be connected to the sleeve itself. This circular wall may also be removable.

Many variations are possible to the device of the invention without departing from the scope of the invention. As shown in FIG. 4, instead of engaging the lip as the first liquid-tight means in the circular interior formed by the inner wall edge and the bonding support surface, the lip is bonded near the inner edge. It may also face the support surface. An O-ring or other type of fitting may be used as the second annular liquid tight means.