RU2410594C1 - End fitting of flexible pipeline - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention refers to machine building, particularly to end fitting of flexible pipeline and can be implemented in oil and gas wells for well tubing. The end fitting of the flexible pipeline consists of a nipple matching and installed into internal diameter of the flexible pipeline; the nipple has conic notches on an external side and internal thread for connection with pipe accessories. On the external side of the nipple there is made external thread; a capture nut and a stop sleeve with external thread on an upper cone are arranged on external thread of the nipple, below of which there is made a lug in form of big bases of a cone facing one another. A lower end of the nipple under the lug has conic notches; on external surface of the stop sleeve there is made external thread; a case with internal thread on ends is screwed on this thread; inside the case there is successively arranged a collet with flexible elements; on internal surface of the elements there are made conic notches facing external surface of the flexible pipeline; also, the latter consists of an expanding sleeve and a bottom box. The expanding sleeve from external side envelops the flexible elements and at the end contacts with the bottom box, while the case with internal thread on ends envelops the flexible element and the expandable sleeve clasping the collet. The end fitting of the flexible pipeline corresponds to an internal pipe out of polyethylene reinforcing load bearing layer of filaments; coils of spiral winding enveloped with a polyethylene external coating are wound around the bearing layer at a specified lead.

EFFECT: increased bearing capacity of end fitting of flexible pipeline; uniform distribution of axial stretching load on all elements of pipeline structure; sealing circular gap at installation of elements of end fitting on flexible pipeline sustaining internal and external pressure of reservoir fluid.

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Description

FIELD OF THE INVENTION

The invention relates to mechanical engineering, in particular to the end connection of an elastic pipeline, and can be used in oil and gas wells as tubing.

State of the art

A pipe connection with a mortise ring is known, which is intended to secure the docking unit on plastic pipes, with one pipe screwed onto the thread of the fitting and the other loosely into the conical bore, a crimp ring with a conical surface is installed between the pipe and the boring, an expansion sleeve is inserted inside the pipe with a collar and a tapered outer surface, a union nut is installed on the external thread of the fitting, and when tightened, the latter interacts with the end of the ring, which, in turn, when interacting and with the inner cone of the nipple compresses the pipe from the outside, at the same time, the sleeve rests with its shoulder in the bottom of the nipple bore. The pipe in this position is clamped between the sleeve and the ring (see US Pat. Belgium, Cl. F16L No. 738524. Declared. 08.09.1969, publ. 04.04.1973).

The disadvantage of this pipe connection is that the connection allows you to provide strength and tightness of the connection for elastic pipes, for example rubber, uniform in composition in cross section, however, this connection has limitations on the perception of axial load. The magnitude of the axial load depends on the strength characteristics of the material from which they are made.

For flexible pipes with a combination of several structural layers of materials of various properties, such a connection is not practical, for example, for equipping deep gas wells, due to the impact of high axial loads.

Known pipe connection, which consists of a fitting with an external thread, an elastically deformable sleeve and a union nut. An elastically deformable metal sleeve is put on the pipe, having annular beads on the inner surface. When the nut is screwed onto the fitting, the sleeve is axially compressed and radially deformed, with annular collars being introduced into the pipe body. This ensures the fastening and sealing of the pipe in the connection (see US Pat. Cl. F16L No. 4221968, declared. 23.01.1970, publ. 01.03.1972).

The disadvantage of this connection is the same as in the first fitting, the fact that the device is applicable for elastic pipes made of elastically deformable material. The perception of axial force by the pipe and connecting elements, from the point of view of permissible axial load, directly depends on the strength characteristics of the material from which they are made. In well-known literary sources it is shown that materials such as rubber, polyethylene, vinyl plastic, etc. possess low strength, which limits the scope of these pipes with this connection node.

Known collapsible sealing of high-pressure hoses, which implements the principle of perception of axial tensile load when directly fixing the metal braid in the metal parts of the end connection (see AS SU No. 1460514, IPC F16L 38/26, publ. 22.09.1986, publ. 02/23/1989, bull. No. 7).

The disadvantage of this collapsible sleeve termination is its low reliability.

A known tube of fibrous composite material with metal end pipes connected to it by a tapered thread, the thread on the pipes made in different directions with a profile in the form of a rectilinear section with a rounded undercut, in which there is a rod curved in a conical spiral with 180 wrapped around it hail. layer by layer of composite pipe material and a step in the radial direction equal to the thickness of the layer of wrapped fibers.

In the pipe, the magnitude of the undercut is not less than the sum of the dimensions of the diameter of the rod and half the thickness of the layer of fibrous material wrapped around it.

A known method of manufacturing a pipe from a fibrous composite material with metal end pipes, including the operation of winding layers of fibrous material of the pipe and between them, winding along the helical line of the glass fiber, followed by curing in the binder material and attaching to the pipe ends by conical threading of metal pipes, first at the technological snap-mandrel release the right and left nozzles with the location of the vanishing points of the thread on one generatrix, and then wrap the ste zhni undercuts into threaded pipes simultaneously with a fibrous composite material pipe.

A device for manufacturing a pipe from a fibrous composite material with metal end pipes, comprising a mechanism for supplying fibrous material in the form of movable and fixed carriages, a removable mandrel and a screw screw connected to a rotation drive, while it is equipped with special handlers associated with movable carriages, which connected to the lead screw, on one part of which the right and the left threads are made (see Pat. RU No. 2083905, IPC F16L 23/02, publ. 07/10/1997).

The disadvantage of this pipe, the method of its manufacture and device for its implementation is the low reliability and strength of the connection.

A device is known that is implemented in a method of fixing metal connection pipes at the ends of a fiberglass pipe, including winding onto the mandrel of the prepreg, installing metal connection pipes at the ends of the fiberglass pipe, while winding the prepreg with a soluble product content of at least 80%, volatile products and moisture 1.5 -3% and a binder 38 + 2% is carried out on a mandrel heated to a temperature that provides an elastic state of the binder, on a fiberglass pipe formed as a result of the said winding the end bosses are wound with the same prepreg heated to the elastic state of the binder to a diameter equal to the outer diameter of the wound part of the metal nozzles of the compound, then the mandrel with the prepreg wound is cooled to ambient temperature, the outer surface of the end bosses is pierced under the sliding fit of the inner diameter of the metal nozzles connections, on the outer surface of the end bosses perform annular grooves on the outer and inner surfaces of the metal part to be wrapped of the connecting pipes, glue is applied, metal connection pipes are pressed onto the end bosses, after which ring ridges are made on the outer surface of the connection metal pipes in the zones corresponding to the zones of the ring grooves on the outer surface of the ring bosses, the ring rings are filled with glue and glass-wound into them flush with the outer surface of the metal connection pipes, then on the outer surface of the metal connection pipes the same prepreg is wound Dima width preheated to a temperature condition providing elastic binder, whereupon fiberglass tube with metal pipes compound is heat treated and then removed from the mandrel (see. US Pat. RU No. 2257506, IPC F16L 13/00, publ. August 10, 2004).

The disadvantage of this device for implementing the method is the design complexity, low reliability of the tightness of the mating parts.

An analysis of the technical solutions to this problem showed that UK patent No. 21217419, IPC F16L 33/18, published on 10.25.1989, “Device for connecting a hose to a pipe”, in which the outer surface of the hose is in close contact with the inner surface of the element, is also known. The hose is fixed using the locking sleeve, the inclined surface of which contacts the protrusion on the element, that is, the principle of compression of the hose and its tight girth of the pipe due to the use of the conical locking sleeve are known. Equipping a flexible pipe (according to AS SU No. 942282) with such a tip will not allow uniform distribution of the axial load across all components of the flexible pipe.

The closest in technical essence and the achieved positive effect and adopted by the authors for the prototype is a tip for attaching a sleeve with a metal braid, which consists of a sleeve, a nipple with an external thread, an elastic element and a union nut. When assembling the tip, the sleeve is screwed onto the sleeve first, then the nipple assembled with the elastic element and the union nut is screwed into the sleeve. Sharp edges on the inner surface of the nipple cut from the end into the body of the flexible sleeve. The sleeve is held in the tip sleeve by a metal braid (see US Pat. NKI 285-119, IPC F16J 39/02 “Tip for a flexible sleeve” No. 3752506, declared September 18, 1972, published on August 14, 1973) .

The disadvantage of this tip is that, compared with the above analogs, the connection allows you to perceive large axial loads, locked on a metal braid, which has a large bearing capacity. However, the design does not have specific nodes that directly enter into the force-loaded contact with the metal braid, so we can assume that this connection also has a limit on the perception of significant axial loads characteristic of deep oil and gas wells.

Disclosure of invention

The objective of the invention is to develop an end connection of an elastic pipeline with an increase in the load-bearing capacity of an end connection of an elastic pipeline, the ability to distribute axial tensile load across all structural elements of a pipeline, seal an annular gap when installing end connection elements on an elastic pipeline, and perceive the internal and external pressure of the formation fluid.

The technical result that can be obtained using the present invention is to increase the bearing capacity of the end connection of the elastic pipe, the possibility of distributing the axial tensile load across all structural elements of the pipeline, sealing the annular gap when installing the end connection elements on the elastic pipe, the perception of internal and external pressure formation fluid.

The technical result is achieved using the end connection of an elastic pipe containing a nipple with an external thread, an elastic element and a union nut, while it is equipped with a locking sleeve with an external thread on the upper cone, a body with an internal thread mounted on the external thread of the locking sleeve, and a packing follower, mounted on the internal thread of the housing, while the nipple is made with the possibility of installation under the inner diameter of the elastic pipe, with a conical notch on the outside and a protrusion in the form not cones facing each other with large bases, the union nut is located on the external thread of the nipple, and a collet with elastic elements is installed in series inside the case, on the inner surface of which there are conical notches facing the outer surface of the elastic pipe, the latter also contains an expandable sleeve the sleeve encompasses the elastic elements from the outside and enters the end connection with the packing follower, and the housing with the internal thread at the ends is made to cover the elastic element and the expansion sleeve, covering the collet, while the elastic pipe is an inner pipe made of polyethylene, reinforcing the load-bearing layer of threads, on which with a certain step are wound spiral coils, covered by a polyethylene outer sheath.

Brief Description of the Drawing

The drawing shows the end connection of the elastic pipe, General view.

The implementation of the invention

The end connection of the elastic pipe consists of a nipple 1, configured to fit under the inner diameter of the elastic pipe, with a tapered notch on the outside and with an internal thread 2 for connecting to the sub, for example, fountain fittings (not shown), while on the outside of the nipple 1, an external thread 3 is made, on which a union nut 4 and a locking sleeve 5 with an external thread 6 on the upper cone (not shown) are located, and a protrusion is made below the location of the external thread 3 on the nipple 1 7 in the form of cones facing each other with large bases, under the protrusion 7, the lower end 8 of the nipple 1 is provided with a conical notch 9, and on the outer surface of the locking sleeve 5 an external thread 6 is made, on which the housing 10 with an internal thread at the ends, inside the housing 10 a collet 11 is installed in series with elastic elements 12, on the inner surface of which conical notches 13 are made, facing the outer surface of the elastic pipe, the latter also consists of an expanding sleeve 14, a packing follower 15, and an expanding one I sleeve 14 covers the elastic elements 12 from the outside and is in end contact with the packing follower 15, and the housing 10 with internal thread at the ends is configured to cover the elastic element 12 and the expanding sleeve 14, covering the collet 11, and the end connection of the elastic pipe is inner pipe 16 made of polyethylene, a reinforcing load-carrying layer 17 of threads, on which, with a certain step, coils of the spiral winding 18 are wound, covered by a polyethylene outer sheath 19 (description of the design of the elastic pipe rovoda shown in the insert of the magazine "Oil Industry" №4, 1988, Moscow, "Nedra", s.40-41).

The installation of the end connection of the elastic pipe is as follows.

Reinforce the load-bearing reinforcing layer 17 threads at the end of the elastic pipe from the inner pipe 16 and from the outer polyethylene sheath 19, the turns of the spiral winding 18 are also removed at this length.

The length of the released section of the elastic pipe from the inner pipe 16 of the outer shell 19 and the spiral winding 18 is equal to the total length of the forming cones on the protrusion 7 of the nipple 1 plus 15 ÷ 20 mm

Before installing the nipple 1, on the outer surface of the polyethylene outer shell 19, a packing follower 15, a lock sleeve 5, a collet 11 with elastic elements 12 are successively installed. A housing 10 is guided from the outside to the lock sleeve 5.

The lower end 8 of the nipple 1 with a tapered notch is introduced into the axial channel 16 of the inner pipe 16. The reinforcing load-carrying layer 17 of the elastic pipe threads is pushed onto the protrusion 7 of the nipple 1 and the ends above it are pressed against the body of the nipple 1 under the external thread 3.

In this position, the locking sleeve 5 is installed on the fixed ends of the reinforcing load-carrying layer 17 of the threads and the union nut 4 is tightened, in this position, the housing 10 is screwed onto the external thread 6 of the locking sleeve 5, into the formed annular gap between the inner surface of the housing 10 and the outer surface of the polyethylene sheath 19 a collet 11 is introduced with elastic elements 12, then an expanding sleeve 14 is installed on the outer surface of the elastic elements 12, a packing follower 15 is inserted into the thread of the housing 10 and tightened This leads to the movement of the expansion sleeve 14 upward relative to the elastic elements 12 of the collet 11, which move radially to the axis of the elastic pipe, and the introduction of conical notches 13 into the body of the polyethylene shell 18, and the pitch of the conical notches 13 on the elastic elements 12 of the collet 11 is selected so that the protrusions are located between the turns of the spiral winding 18.

To equip oil and gas wells with such an elastic pipe, it is necessary that both ends have such a conical connection. An adapter (not shown) is screwed into the internal thread 2 of the nipple 1 to be connected to a well fountain (not shown).

This design of the end connection of the elastic pipe allows the main axial load from the weight of the elastic pipe to be reported to the reinforcing load-bearing layer 17 of the threads, the introduction of the conical notches 13 located on the inner surface of the elastic elements 12 of the collet 11, in cooperation with the material of the polyethylene sheath 18 contributes to the formation of a tight contact , the location of the conical notches 13 on the elastic elements 12 of the collet 11 after mounting the elements of the end connection between the turns of the spiral bmotki 18 allows part of the axial load close to them.

Thus, the technical result that can be obtained by implementing the invention is as follows:

- increase the bearing capacity of the end connection of the elastic pipe;

- the possibility of distributing the axial tensile load across all structural elements of the elastic pipeline, depending on the strength characteristics of the material of the inner pipe, the outer polyethylene sheath, the reinforcing load-bearing layer of threads;

- the ability to seal the annular gap when installing the elements of the end connection on an elastic pipe.

The invention in comparison with the prototype and other known technical solutions has the following advantages:

- increase the bearing capacity of the end connection of the elastic pipe;

- the possibility of distributing the axial tensile load across all structural elements of the elastic pipeline, depending on the strength characteristics of the material of the inner pipe, the outer polyethylene sheath, the reinforcing load-bearing layer of threads;

- the ability to seal the annular gap when installing the elements of the end connection on an elastic pipe;

- the ability to perceive the internal and external pressure of the reservoir fluid, when equipped with elastic pipelines of oil and gas wells;

- the ability to equip oil and gas wells as tubing with small external diametrical dimensions of the end connection and the axial channel.

Claims (1)

An end connection of an elastic pipe comprising a nipple with an external thread, an elastic element and a union nut, characterized in that it is equipped with a locking sleeve with an external thread on the upper cone, a housing with an internal thread mounted on the external thread of the locking sleeve and a packing follower mounted on the internal thread case, the nipple is made with the possibility of installation under the inner diameter of the elastic pipe with a conical notch on the outside and a protrusion in the form of large facing each other the cones, the union nut is located on the external thread of the nipple, and a collet with elastic elements is successively installed inside the case, on the inner surface of which there are conical notches facing the outer surface of the elastic pipe, the latter also contains an expansion sleeve, the expansion sleeve covering the elastic elements and is included in the end connection with the packing follower, and the body with the internal thread at the ends is made with the possibility of covering the elastic element and the expanding sleeve Covering the collet, wherein the flexible conduit is an inner tube made of polyethylene, a layer of reinforcing load-bearing yarns, which are wound with a certain pitch spiral coil windings covered by a polyethylene outer sheath.

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