RU185638U1 - SEALED THREADED CONNECTION - Google Patents

Abstract

This utility model relates to types of threaded pipe joints, in particular to threaded joints of casing strings, sections of oil and gas pipelines, ensuring tightness through the use of several metal-metal seal assemblies. The utility model can be used to directly connect pipes without the use of additional couplings. In accordance with this utility model, a tight threaded connection is formed by a truncated cone-shaped nipple end of the first pipe having a section with an external conical thread and a sleeve end of the second pipe having a section with internal conical threads, which, when making up, form seal assemblies formed by sections of the conical surfaces of the nipple and couplings free from thread ovogo end, box-end bearing end and stubborn shoulder pin end, bearing end pin end and box-end abutment shoulder. The thread-free portion of the conical surface of the nipple end contains a belt configured to interact with a groove of the coupling end made on a thread-free portion of the conical surface, the thread-free portions of the conical surfaces of the nipple and coupling ends being made with a taper equal to the taper of the thread, and mating thrust surfaces are made essentially perpendicular to the axis of the thread. 8 C.p.F., 7 ill.

Description

This utility model relates to types of threaded pipe joints, in particular to threaded joints of casing strings, sections of oil and gas pipelines, ensuring tightness through the use of several metal-metal seal assemblies. The utility model can be used to directly connect pipes without the use of additional couplings.

A technical solution is known according to the patent of the Russian Federation for utility model No. 169118 “Threaded connection of a pipe nipple with a sleeve covering it” (s-th UK of LLC “TMS group”, application No. 2016143042 dated 01.11.2016, publ. 03.03.2017, IPC F16L 15 / 04). According to the formula and the description of the technical solution, the threaded connection of the pipe nipple with the sleeve enclosing it comprises a threaded section with a tapered thread made on the nipple and passing into the sealing section with a convex toroidal surface made from the side of its end, while on the inner surface of the end section of the coupling it is made with the sides of its end face a tapered thread that passes into a tapered sealing section with an annular ledge at the end with the possibility of forming a tight connection between and toroidal surfaces with a threaded connection of the end sections of the nipple and the coupling, and between the toroidal and threaded sections of the nipple on the outer surface, a transition section is made in the form of a concave toroidal surface.

The features of this technical solution is the implementation of the outer spout of the nipple end of the pipe having the shape of a toroidal surface, the inner surface of the spout having a bore, and the end of the spout having an inner bevel (inverse angle). These signs affect the relatively low manufacturability of the product. So, due to the implementation of the connected elements with variable taper, when threading, it becomes necessary to use three different threaded plates. It is also necessary to use a complex set of measuring equipment for precise threading.

A technical solution is known according to the patent of the Russian Federation for invention No. 2134371 “Integral butt joint for joining two pipes” (szl Agip S.p.A., application No. 94037593 from 10/18/1994, publ. 08/10/1999, IPC F16L15 / 04 ) According to the description, an integral butt joint for connecting two pipes, in which from the annular edge of the outer pipe there is an inner socket of decreasing cross section, interacting with an interference fit with the corresponding external back socket. An external return bell is made on the end part of the inner pipe near the overhanging rear flange of the latter to form another tight all-metal seal with an interference fit in addition to another impermeable seal already existing on the front end of the end part of the inner pipe. The invention is aimed at improving the tightness of the connection.

The disadvantages of this solution is the implementation of the end parts of the connected pipes with an external upsetting ends, which leads to a change in the outer diameter of the pipe body. In addition, a section of the conical surface free from thread is made with a taper of 1:10, while the thread is cut with a taper of 1:12. This feature of execution leads to a complication of the technological process of pipe production.

A device is known according to US patent for the invention No. 5788401 "Rod joint (connection rod)" (zl BLY IP Inc, z.№US08772860 from 1996-12-24, publ. 1998-08-04, IPC F16L 15/001, ЕВВ 17/042). According to the formula and description of the technical solution, a design for connecting the rods is proposed, consisting of nipple and socket ends, respectively containing sections with tapered threads and two seal assemblies containing persistent annular ledges and tightly fitting conical surfaces.

The disadvantage of this technical solution is the docking of the sealing units exclusively in the end stops. This feature does not allow for sufficient sealing of the connection.

Closest to the proposed technical solution is the device according to the patent of the Russian Federation for the invention No. 2642922 "Threaded connection for steel pipes" (s-Nippon Steel End Sumitomo Metal Corporation, Wallurek Oil and Gas Hydrome, z.№2016107380 dated 04.09.2014, publ. 01/29/2018, IPC F16L 15/04). According to the description of the technical solution, the invention relates to threaded joints for steel pipes. A threaded joint for steel pipes comprises a sleeve, which is the opening end of the second pipe, and a nipple in the form of a truncated cone, which is the end of the first pipe and inserted into the sleeve. The nipple contains an external thread section, which is a conical thread, and a sealing section, which contains a conical surface, and the coupling contains an internal thread section, which is a conical thread, and a sealing section, which contains a conical surface, and in the states before screwing the nipple and coupling is minimal the diameter of the conical surface of the nipple is less than the maximum diameter of the conical surface of the coupling

The disadvantage of the technical solution is variable taper, leading to low manufacturability.

Thus, the prior art does not contain information about technical solutions that solve a number of technical problems. So, the technical problem solved by the proposed utility model is the creation of a threaded connection that allows for reliable isolation from the external environment, while having high adaptability, expressed in simplifying the production process of product components and ensuring high performance.

In accordance with this utility model, a hermetic threaded connection formed by a truncated cone in the form of a nipple end of the first pipe having a section with an external conical thread and a sleeve end of the second pipe having a section with an internal conical thread, which, when screwed together, form seal assemblies formed free from thread sections of the conical surfaces of the nipple and coupling ends, the persistent end of the coupling end and the persistent ledge of the nipple end, the persistent end of the nipple to end and persistent ledge coupling end. The thread-free portion of the conical surface of the nipple end contains a belt configured to interact with a groove of the coupling end made on a thread-free portion of the conical surface, the thread-free portions of the conical surfaces of the nipple and coupling ends being made with a taper equal to the taper of the thread, and mating thrust surfaces are made essentially perpendicular to the axis of the thread.

Signs common with the known technical solution are the execution of the ends of the pipe in the form of a truncated cone, with the possibility of connection, the execution on the nipple end of the first pipe section with an external tapered thread, execution on the pipe end of the pipe section with an external tapered thread. The devices are also characterized by the presence of seal assemblies formed by thread-free portions of the conical surfaces of the nipple and coupling ends, the persistent end of the coupling end and the persistent shoulder of the nipple end, the persistent end of the nipple end and the persistent shoulder of the coupling end.

Distinctive features of the proposed technical solution are the presence on the thread-free portion of the conical surface of the nipple end of the girdle adapted to interact with the groove of the coupling end made on the thread-free portion of the conical surface, thread-free portions of the conical surfaces of the nipple and coupling ends are made with taper, equal taper of the thread, and the mating thrust surfaces are made essentially perpendicular to the axis of the thread.

In the first particular case of execution, a threaded connection that differs from the implementation in the General case in that the tapered thread is made resistant.

To clarify this particular case, the connection is additionally characterized in that the thread pitch is 5.08 mm.

In the second particular case, the connection differs from the implementation in the General case in that the tapered thread is made trapezoidal.

To clarify this particular case, the connection is additionally characterized in that the thread pitch is 4.233 mm.

In the third particular case, the connection is additionally characterized in that the connected pipes are made with an internal upsetting ends.

Also, in accordance with the fourth particular case, it is advisable to perform the conical surface of the connected pipes with a taper of 1:16.

In accordance with the fifth particular case of execution, the roughness of the surfaces forming the seal nodes is Rz = 40 μm. It is advisable to connect the ends of the pipes in an interference fit.

The device in the General case of implementation consists of a pair of connected end parts of the pipes. The nipple end of the first pipe is screwed into the sleeve end of the second pipe until the stop face of the nipple end and the stop ledge of the sleeve end are mated.

The persistent end face of the coupling end and the persistent ledge of the nipple end also mate as a result of make-up.

The inner diameter of the section of the sleeve containing the bore allows you to place the nipple end containing the belt to the position at which the end of the nipple interacts with the step of the sleeve.

Thus, several seal assemblies, in addition to ensuring the tightness of the joint, even under the action of high internal and external pressures, also perform the function of maintaining the tightness in the event that both seals are damaged, which can happen during the make-up operation of two connected pipes.

When making up the pipe and the coupling, the sealing groove of the coupling contacts the sealing belt of the nipple end. When the pipe and the coupling are fully screwed up, the pipe end abuts against the sealing lip of the coupling, forming two seal assemblies, in the end part of the nipple. The execution of the belt of the nipple connected to the groove of the coupling allows you to create a high-tight seal, contributing to the formation of a seal assembly, the elements of which are tightly adjacent to each other due to the conjugation of the right angles of the thrust groove of the coupling and the end of the pipe nipple. In the process of making such a connection, the mating surfaces are heated, as a result of which the process proceeds, which are close in physical essence to friction welding.

Direct coupling of the end face of the nipple with the thrust protrusion of the coupling allows for a more accurate connection, and also helps to simplify the production of measurements in the manufacture of threads.

The equal taper of the thread and seal nodes made on the conical surface of the parts of the connection, simplifies the manufacture of the connection by increasing the manufacturability of production, expressed in reducing the number of operations. In addition, this feature allows the use of less complex measuring and production equipment.

The use of persistent conical threads, as disclosed in one of the special cases, allows the utility model to be used in cases where there are large unilateral loads acting in the axial direction, such as, for example, in well construction. The profile of the resistant thread is a trapezoid, one side of which has a slight angle of inclination and is the working side of the profile, and the other side has a more pronounced angle of inclination and is not used as the working one.

The execution of the thread with a pitch of 5.08 mm and the use of a trapezoidal thread allows you to get a connection that can absorb significant mechanical stress. For a number of small diameters of the connected pipes (less than 105 mm), a useful model provides for a thread pitch of 4.233 mm.

To ensure a sufficient level of adhesion, the utility model provides a certain value for surface roughness. At the beginning of the process of making ends of pipes, the friction surfaces first contact along the vertices of the microroughnesses, as a result of which they are cut and plastic deformed. By the end of the make-up process, the height of the initial roughness decreases, and the area of actual contact increases, which leads to a decrease in contact pressures. At the same time, during make-up, as a result of friction of the mating surfaces, the surface of the pipe ends to be joined locally is heated, which leads, in some cases, to a result similar to friction welding, making it possible to obtain a reliable integral connection without losing the physical and mechanical properties of the pipes. The surface fatigue significantly depends on the fatigue resistance of parts. The applied roughness value for the sections of the conical surfaces of the nipple and coupling ends allows, on the one hand, to obtain the optimal contact area for mating the parts to be joined, and on the other hand, to allow the heating effect of surfaces to form a reliable hermetic joint during make-up.

The internal upsetting of the pipe, in accordance with a particular case, is necessary in order to cut the female thread and the nipple end of the pipe, without changing the outer diameter of the pipe. The planted part is inside the pipe diameter on both sides at a length of about 150 mm, the rest of the pipe has a normal wall, depending on the diameter of the pipe.

Performing an interference fit helps to increase the tightness of the formed connection due to a more snug fit of the contacting surfaces.

The taper value of 1:16 allows one to obtain optimal thread parameters at a thread pitch that ensures the perception of the necessary vertical loads of the assembled joint, as well as to increase the manufacturability of production using cutting tools with threaded inserts of the same profile for threading.

Thread runaway is used for uniform make-up (without jerking) of pipes among themselves

The thread portion of the sleeve end of the pipe to be joined may comprise a thread portion with an incomplete profile.

The proposed utility model is illustrated by the following figures:

FIG. 1 - Nipple part of the pipe with an internal upsetting end;

FIG. 2 - Local view of the end of the connection;

FIG. 3 - The coupling part of the pipe with an internal upsetting end;

FIG. 4 - Tight threaded connection in the make-up process;

FIG. 5 - Fully screwed tight seal;

FIG. 6 - Conical persistent thread;

FIG. 7 - Conical trapezoidal thread;

The following positions are indicated in the figures:

1 - nipple end of the connected pipe;

2 - the coupling end of the connected pipe;

3 - persistent end of the nipple end;

4 - persistent ledge of the nipple end;

5 - persistent end of the coupling end;

6 - persistent ledge coupling end;

7 - a persistent belt;

8 - groove;

9 - external thread;

10 - internal thread

11 - seal assembly formed by the end face of the nipple and the step of the coupling ends;

12 - seal assembly formed by the end face of the sleeve and the step of the nipple ends;

13 - seal assembly formed by a persistent girdle and a groove.

To understand the principles of operation and features of various implementations of the utility model, the following is a description of the figures of the technical solution. Although the preferred description of the technical solution is explained in detail in the text of the description, it must be understood that other implementation options are possible. Accordingly, there is no need to limit the scope of legal protection of a technical solution exclusively to the presented implementations and lists of nodes and components. The utility model can be implemented in other ways. However, when describing preferred technical solutions, for clarity of understanding of the basic principles of the utility model by a specialist, it is necessary to clarify the terms used in the description.

It should be noted that the nodes and parts of the device used in the singular in the description and formula also represent multiple forms, unless expressly stated otherwise. For example, an indication of a constituent element of a device also means an indication of the totality (set) of such elements.

Also, when describing preferred embodiments, special terms are used to provide clarity of understanding. The term is intended to be used in the broadest sense in which it can be construed by those skilled in the art and includes all technical equivalents used in the same way and for the same purpose. So, in particular, the term "truncated cone" refers to the form of the end parts of the pipe. In the context of this utility model, a truncated cone indicates the presence of a counter inclination of the pipe walls relative to the horizontal axis. The term “seal assembly” is a combination of structural metal sealing and thrust elements of a threaded joint, which, when mechanically screwed together, provide a high tightness of the threaded joint as a result of mating surfaces. In the context of a utility model, seal assemblies include thread-free sections of the surfaces of the end parts of the pipes to be joined, in particular, the points of joining of the ends and ledges of the nipple and sleeve ends and the conical surfaces of the nipple and sleeve parts containing the girdle and groove, respectively, formed when making up. The term "girdle" refers to the protruding part of the conical surface of the nipple and can also be characterized as a shoulder or an annular ridge. The outer surface of the girdle has the same taper as the threaded connection. In the case of this utility model, the term “groove” is used to describe a substantially annular groove or bore formed on a portion of the conical surface of the sleeve end.

The term “mate” refers to the interaction of the persistent ends and ledges of the nipple and the coupling. Essentially, this means that these elements are in contact over the entire surface area with full screwing of the nipple and coupling parts.

The words “consisting”, “comprising”, “including” mean that at least one of the indicated component, element, part or step of the method is present in the composition, object or method, but does not exclude the presence of other components, materials, parts, steps method, even if such a component, material, part, step of the method performs the same function as the specified.

The materials from which the various elements of the present utility model are made, indicated below when describing examples of specific embodiments of the device, are typical, but not required for use. The materials indicated in these examples may be replaced by numerous analogs that perform the same function as the examples of materials described in the description.

Turn to the attached figures. In FIG. 1 shows the nipple end 1 of the first pipe in accordance with one specific implementation of the present utility model.

The first pipe containing the nipple end 1 is made with a diameter of 105 mm, with a wall thickness of 7.4 mm, with an inner upset end with an upset length of 150 mm. The nipple end 1 has an outer wall in the shape of a truncated cone, with a taper of 1:16. An external abutment thread with a taper of 1:16 with a pitch of 5.08 mm and a height of 1.6 mm is cut into a conical surface of the nipple end, turning into a conical sealing portion containing an abutment girdle 7 ending with an abutment end 3 at the end with the possibility of forming a tight joint when threaded the connection of the end sections of the nipple end 1 of the first pipe and the sleeve end 2 of the second pipe.

In FIG. 2 shows a portion of a seal assembly comprising a girdle and a bore. A chamfer (not shown) has been removed from the edge of the girdle.

In FIG. 3 shows the sleeve end 2 of the second pipe. The second pipe is made with a diameter of 105 mm, with a wall thickness of 7.4 mm, with an internal upsetting end with an upsetting length of 150 mm. The sleeve end 2 has an outer wall in the form of a truncated cone, with a taper of 1:16. An internal threaded thread with a taper of 1:16 with a pitch of 5.08 mm and a height of 1.6 mm is cut in a section of the conical surface of the nipple end, turning into a conical sealing section containing a groove 8, turning into a stop ledge 6 with the possibility of forming a sealed connection with a threaded connection end sections of the nipple end 1 of the first pipe and the sleeve end 2 of the second pipe.

FIG. 4 illustrates a compound in a state of incomplete make-up. The image shows that the stop band of the nipple end interacts with the groove of the coupling end.

In FIG. 5 shows the connection in working condition. When making up the first and second pipes, the nipple end 1 of the first pipe enters the sleeve end of the second pipe. The belt 7 of the nipple end of the first pipe interacts with the groove of the sleeve end 2 of the second pipe, the thread teeth engage with the counterpart. The screwing is carried out until the coupling of the persistent end of the nipple end with the persistent shoulder of the coupling, as well as the persistent ledge of the nipple end with the persistent end of the coupling. The specified pairing occurs simultaneously. Thus, by screwing to the end of the nipple part 1 of the first pipe into the coupling part 2 of the second pipe, three completely metal tight seals are tightened to ensure tightness of the seal in any operating conditions, namely: the first seal assembly 11, formed by the end of the nipple and the step of the coupling of ends, the second seal assembly 12, formed by the end face of the coupling and the shoulder of the nipple ends, and the third seal assembly 13, formed by a thrust belt and a groove.

Depending on the operating conditions, threads applied to portions of the conical surfaces of the nipple and coupling ends may be resistant, as shown in FIG. 6 or trapezoidal as shown in FIG. 7. The pitch of the thread can be, mm: 4,233 or 5,08, depending, including from vertical loads during operation.

The geometric dimensions of the conical and coupling ends, as well as their components, depend, inter alia, on the diameters of the pipes to be connected. The principle of selecting the type of thread depends on the scope of the present connection and the desired technical characteristics. The key to this utility model is the presence of several compaction nodes.

The exemplary embodiments disclosed above are provided to illustrate the industrial applicability of the device and to provide a general impression of the possibilities of the proposed connection. The scope of legal protection of a technical solution is determined by the formula of the utility model, and not the description provided, and all changes made with the use of equivalent features fall under the legal protection of this utility model.

Claims (9)

1. A sealed threaded connection formed by a truncated cone-shaped nipple end of the first pipe having a section with an external tapered thread and a sleeve end of the second pipe having a section with an internal tapered thread, forming sealing assemblies formed by thread-free sections of conical surfaces nipple and coupling ends, persistent end of the coupling end and persistent ledge of the nipple end, persistent end of the nipple end and persistent ledge of the coupling end, excellent the fact that the thread-free portion of the conical surface of the nipple end contains a belt configured to interact with a groove of the coupling end made on a thread-free portion of the conical surface, the thread-free portions of the conical surfaces of the nipple and coupling ends being made with a taper equal to the taper threads, and the mating thrust surfaces are made essentially perpendicular to the axis of the thread. 2. The compound according to claim 1, characterized in that the tapered thread is made resistant. 3. The compound according to claim 2, characterized in that the thread pitch is 5.08 mm. 4. The compound according to claim 1, characterized in that the tapered thread is made trapezoidal. 5. The compound according to claim 4, characterized in that the thread pitch is 4.233 mm. 6. The compound according to claim 1, characterized in that the roughness of the surfaces forming the seal nodes is Rz, μm: 40; 7. The connection according to claim 1, characterized in that the connected pipes are made with an internal upsetting ends. 8. The connection according to claim 1, characterized in that the connection of the ends of the pipes is tightened. 9. The compound according to claim 1, characterized in that the conicity of the surface of the ends of the pipes is 1:16.

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