RU165000U1 - FLEXIBLE HIGH PRESSURE POLYMERIC REINFORCED PIPE - Google Patents

Abstract

1. A flexible high-pressure reinforced pipe having an inner and outer layers made of a polymer material, between which at least one reinforcing layer of metal tapes is located, characterized in that the metal tapes are spirally wound with 4 coils, the first two coils of the metal tape having the same direction, and the subsequent tufts have the opposite direction. 2. The flexible high-pressure reinforced pipe according to claim 1, characterized in that the angle of the coils of metal tapes relative to the axis of the pipe has a value of 55 ° ± 5.3. The flexible high-pressure reinforced pipe according to claim 1, characterized in that there is a gap between the metal tapes of one winding, comprising from 5 to 15% of the width of the tape. The flexible high-pressure reinforced pipe according to claim 1, characterized in that the thickness of the metal tape is 0.3-1.5 mm.

Description

The utility model relates to the oil and gas industry and can be used for the collection and transportation of hydrocarbons, water, gas and the operations of supplying various fluids and reagents to the wells necessary for the development, operation and maintenance of the wells. Flexible polymeric reinforced pipes have several advantages over steel pipelines connected by welded joints or twisting of threaded joints. The polymer elements of a flexible reinforced pipe reliably protect metal elements from environmental influences. Flexible reinforced polymer pipe can be made in one long length. When installing the pipeline, a relatively small number of connections of pipe sections is performed, which saves time and reduces costs

Known pipes with a nonmetallic core covered with a multilayer sheath of wound metal tape (USSR Author's Certificate No. 185161 by application of March 25, 1963, published July 30, 1966). The metal strip has a stepped shape in cross section. The disadvantage of this design can be considered the greater rigidity of the pipe, since the metal tape has a stepped shape and is attached to the core along the plane with glue. The consequence of the large stiffness of the pipe will be a large bending radius and the inability to wind on a drum. Creating a step shape is possible only for plastic tape, which reduces the mechanical strength of the structure as a whole.

Known non-metallic pipe, consisting of a reinforcing metal tape frame with overlaps with a width of at least half the width of the tape and filler, characterized in that, in order to increase strength and heat resistance, the frame has the shape of a screw conoid with a gap between the turns, and its tape is transversely profiled (USSR Copyright Certificate No. SU 1200066 A). The disadvantage of this design can be considered the large dimensions of such a frame and, as a consequence, the inability to perform a multilayer structure. The strength of the single-layer frame will not be enough to provide resistance to high pressure inside the pipe. It is impossible to provide multilayer winding of a frame of such a shape and combining it into one compact and reliable pipe design.

The closest design of the flexible pipe to the proposed utility model is a reinforced pipe, which has an outer layer and one inner layer made of a polymeric material, between which at least one reinforcing layer is made of a steel tape coated with at least on the one hand with adhesive (Patent RU 151014 U1 of 09.29.14).

The disadvantages of the design of this pipe can be considered a very small ratio of the thickness of the steel tape of the reinforcing layer to the inner diameter of the pipe, which is 0.0006-0.002 and the use of an adhesive layer. A steel strip of this thickness has insufficient strength to the internal pressure in the radial direction and to tensile in the axial direction. When bending the pipe, the adhesive layer prevents the movement of the layers of metal tape along the axis of the pipe and the return of the layers to their original position, which is considered to be the rectilinear position of the pipe. The high rigidity of the design of the pipe with an adhesive layer can cause deformation of the metal frame during bending of the pipe.

The purpose of this utility model is to create an improved design of a high-pressure flexible reinforced polymer pipe capable of withstanding internal pressure up to 20 MPa, axial loads up to 300 kN, with the possibility of its winding on a drum or in a bay.

This goal is achieved by creating a flexible polymer reinforced pipe having an inner and outer layer made of polymeric material, between which there is a reinforcing layer of metal tapes, spirally wound with 4 coils, the first two coils of metal tapes have the same direction, and the subsequent coils have the opposite direction, and the angle of the coils of metal tapes relative to the axis of the pipe has a value of 55 ° ± 5 ^% , and there is a gap between the metal tapes of one coils of from 5 to 15% of the width of the tape, the thickness of which is 0.3-1.5 mm.

The technical result of the application of this invention is the manufacture and use of a flexible high-pressure reinforced pipe for transporting oil, gas and water and other gas-liquid mixtures.

In FIG. Figure 1 shows the construction of a flexible reinforced polymer pipe consisting of an inner layer 1 made of a polymer material, four coils of a metal strip, the first coils 2 and the second coils 3 having the same direction, the third coils 4 and the fourth coils 5 have the opposite direction to the first two coils. The coils of metal tapes are wound at an angle of 6 relative to the axis of the pipe 7. There are gaps between the tapes of each coils 8. An outer layer 9 made of a polymer material is applied over the coils of the metal bands.

The manufacture of the reinforcing layer of a flexible polymer reinforced pipe is performed as follows: the first twist of a metal tape is applied to the polymer pipe at an angle to the axis of the pipe and with a small gap between the turns. A second coil of metal tape is applied over the first coil in the same direction so that it overlaps the gaps between the tapes of the first coil. A third coil of metal tape is applied over the second coil in the opposite direction. The fourth layer of metal tape is applied in the same direction as the third layer, overlapping the gaps between the tapes of the third layer. Thus, applying two coil of tapes (first and second) in one direction and applying two other scrolls (third and fourth) in the opposite direction compensate for the torque that occurs when the pipe is filled with liquid under pressure and prevent the flexible pipe from twisting.

For the correct functioning of the reinforcing layer of the pipe - the coils of metal tapes, when bending the pipeline, it is necessary to ensure that the coils are slipped relative to each other. As shown in FIG. 2, when the pipe bends to an average radius of 10, sections of metal tapes 11 located on the inner radius of bend 12 are compressed, and sections of metal tapes 13 located on the outer radius of bend 14 are stretched. Because the reinforcing tapes have a high modulus of elasticity; the tapes are mutually displaced relative to each other and the gaps between them in the midwife change without changing the geometric dimensions of the tapes themselves. When bending on the outer radius, the gaps increase slightly, while on the inner radius they decrease slightly - due to this, no stress arises in the steel tape during bending of the pipeline. Accordingly, the position of the tapes of the various midwives is changed relative to each other. We will calculate the magnitude of the tension / compression at the inner and outer radii during bending of the pipe.

We calculate the average value of the circumference of the layers according to the formula:

L = 2 * π * R, where

R is the bending radius

We choose a drum with a barrel radius of 1000 mm for winding pipes with an inner diameter of 100 m. In this case, the following winding radii of various sections of the pipe and the corresponding circumference determined by these radii will be obtained. We get the following data:

The average radius of the winding of the reinforcing elements of the pipe, mm - 1200 The outer radius of the winding of the reinforcing elements of the pipe, mm - 1260 The inner radius of the winding of the reinforcing elements of the pipe, mm - 1140 The circumference along the average radius, mm - 7536 The circumference along the inner radius, mm - 8313 The circumference of the outer radius, mm - 6659

As can be seen from the above data, when winding the pipe, the total gap between the sections of tapes located on the inner radius will decrease by 877 mm, and the gap between the sections of tapes on the outer radius will increase by 777 mm. Based on the fact that when winding the pipe, the gaps between the tapes on the inner radius disappear altogether, the total gap between the tapes for a straight pipe should occupy at least 11.6% of the total width of the tapes along the pipe axis. In practice, for various pipe diameters, this value is from 5 to 15%. The change in the gap between the tapes occurs due to the sliding of metal tapes relative to each other.

Metal tape is applied at an angle close to 55 ° to the pipe axis. This winding angle is selected to ensure equal strength of the reinforcing elements in the radial and axial directions. It is known that the condition of equal strength is determined by the expression: tg ² (φ) = 2, where φ≈55 ° is the angle of winding of steel strips to the pipe axis. Layers of a metal tape laid in mutually opposite directions at an angle of φ≈55 ° provide equal strength of the reinforcement system to the action of internal pressure in the axial and radial directions. In practice, it is difficult to ensure the exact angle of the meanings of metal tapes; therefore, it is selected by a certain error, for example, at 5%.

The main strength characteristics for a pressure polymer pipe are the characteristics of the maximum pressure that the pipe and tensile strength can withstand. In the proposed utility model, these characteristics are achieved as follows. Under the conditions when a high-strength material is used as a reinforcing system - a metal tape, the reinforcing system takes on all the load arising from the action of internal pressure, and the polymer layers, due to the large coefficients of relative elongation and small deformation of the reinforcing system, are slightly loaded. In this regard, the strength properties of such pipes are primarily determined by the corresponding characteristics of the steel strip, and the choice of parameters of the reinforcing system: the thickness of the tape, the number of layers of tapes, the tensile strength of the material from which the tape can be made without taking into account the strength and deformation characteristics of the polymer layers . To calculate the reinforcing system for internal hydrostatic pressure, we use the formula:

P = ((2 * e) / (D _H -e)) * [σ], where

P is the internal pressure in the pipe.

D _H is the outer diameter of the pipe,

e is the minimum wall thickness.

[σ] is the temporary tensile strength of the metal tape.

For example, we take three designs of a flexible polymer reinforced pipe:

Design No. 1 according to the patent for utility model RU 151014;

Structures No. 2 and No. 3 are made in accordance with the proposed utility model, where reinforced steel tape is used according to GOST 2284-79 with a permissible tensile stress of 700 MPa and a thickness of 0.3 to 1.5 mm.

The calculation results are shown in table 1

Thus, as can be seen from table 1, the thickness and strength characteristics of the metal tape selected for the reinforcing system in the design of the pipe 1 do not provide the required strength characteristics, namely, they do not provide a working pressure of up to 20 MPa. The choice of high-strength metal tape in pipe designs 2 and 3 with a thickness of 0.3 to 1.5 mm ensures the strength characteristics of the reinforcing system.

The increased thickness of the tape 0.3-1.5 mm is necessary to ensure the breaking strength of the pipe during its installation, as well as to provide the required strength when axial forces occur under the action of internal pressure.

We will calculate the force acting on the end of the pipe under the action of internal pressure:

N = (π * d ^2/4) * P, where

d is the inner diameter of the pipe

P - internal pressure in the pipe

We calculate the tensile strength of the pipeline according to the formula:

F = A * [σ], where

F - breaking strength

A - section of a metal tape

[σ] - allowable stress in the metal tape

The calculated values of the breaking force and the force acting on the end of the pipe under the action of internal pressure for a pipe with a diameter of 50 mm are shown in table 2.

Thus, as can be seen from table 2, the selected range of thickness of the metal tape 0.3-1.5 mm meets the requirements for the tensile strength of the pipeline.

In the proposed utility model, midi of a metal tape are laid in opposite directions. Since metal tapes have a spiral winding - under the action of a tensile force in the reinforcing layer there are torques. In the design of the pipe, the reinforcing layers are superposed in opposite directions and the torques are almost completely balanced.

We will calculate the magnitudes of the torques arising in the coils of the pipe according to the following formulas:

The condition of equilibrium of torques in the coils of the pipe:

+ M ₁ -M ₂ ≈0, where

M ₁ - torque in the first 2 coils

M ₂ - torque in the second 2 coils

M = d ² * n * D _cp * (1+ (tgα) ² ), where

d - take equal to the thickness of the tape

n is the number of tapes in the coils

D _cp is the average diameter of the reinforcement

α - angle of reinforcement

The calculations of the torques for a pipe with a diameter of 50 mm, considered in the previous example, are shown in table 3.

Thus, as can be seen from table 3, the torques are practically compensated in the reinforcing system, and the excess moment of the second winding is directed so that it spins the inner winding and is largely compensated by the internal elastic forces in the pipe.

Claims (4)

1. Flexible high-pressure reinforced pipe having an inner and outer layer made of a polymeric material, between which at least one reinforcing layer of metal tapes is located, characterized in that the metal tapes are spirally wound with 4 coils, the first two coils of the metal tape having the same direction, and the subsequent midwives have the opposite direction. 2. Flexible high-pressure reinforced pipe according to claim 1, characterized in that the angle of the coils of metal tapes relative to the axis of the pipe has a value of 55 ° ± 5 ^% . 3. The flexible high-pressure reinforced pipe according to claim 1, characterized in that there is a gap between the metal tapes of one winding, comprising from 5 to 15% of the width of the tape. 4. Flexible high-pressure reinforced pipe according to claim 1, characterized in that the thickness of the metal tape is 0.3-1.5 mm.

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