AT17396U1 - Tight metal pipe thread connection - Google Patents

Abstract

Tight metal pipe thread connection, formed by threaded end areas, each having an internal supporting conical thread and an external supporting conical thread of two coaxially lying pipes, namely an outer pipe (5) and an inner pipe (6), and by sealing and stop contact surfaces, wherein a sealing surface (7) of the outer pipe ( 5) is conical, with a sealing surface (8) of the inner pipe (6) being toroidal, with the stop surfaces (9, 10) of the outer and inner pipe (5, 6) being conical and with a negative cone angle, γ, to the to the connecting longitudinal axis (X), the inner tube (6) being equipped with an additional cylindrical surface (13) which is coupled on the one hand to that of the toroidal sealing surface (8) and on the other hand to the threaded end area (2), the toroidal Sealing surface (7) in the outer tube (5) of the tube with an outer diameter of D = 4 ½ - 13 ⅜″ has a radius R1 = 70-140mm, where the The inner tube (6) is equipped with an additional conical surface (12) with a cone angle, φ, of 25 - 35% to the longitudinal axis of the connection (X), the additional conical surface (12) having the toroidal sealing surface (8) on the one hand and the conical sealing surface on the other Stop surface (10) of the inner pipe (6) is coupled, the outer pipe (5) having the conical sealing surface (7) with a cone angle, β, of β = φ% to the longitudinal axis of the connection (Х), and between the threaded end area (1) and the conical sealing surface (7) lying inner annular groove (11).

Description

description

The invention belongs to the field of manufacture of tight threaded metal pipe connections in the oil and gas industry, which can be used in the construction of oil and gas wells.

Insufficient tightness of the threaded pipe connections can cause corrosion in the area of the threaded connection and consequent destruction of the casing or petroleum tubing strings.

One of the methods of improving thread tightness is the selection of an optimal ratio of the geometric parameters of threaded fasteners.

A tight metal pipe thread connection is known from EP 0 364 413 B1 «HERMETIC METAL PIPE JOINT», which contains inner and outer elements that can be coupled with conical thread sections and a conical sealing surface at the end area.

The cone inclination of the sealing surfaces of the inner and outer element is in the range of 6.25% - 9.25% to the connection axis.

The disadvantage of the known tight thread connection is that the contact length of the inner element in contact with the corresponding surface of the outer element is very small and the connection cannot withstand high gas or liquid pressure, which can reduce its tightness and operational reliability.

A tight threaded metal pipe connection is known from US Pat. No. 4,623,173 A «SCREW JOINT COUPLING FOR OIL PIPES», which is formed by threaded end regions with internal and external supporting conical threads from the external and internal element.

The sealing surface of the outer element is conical, the sealing surface of the inner element is toroidal with radii of 150 mm and 250 mm.

The disadvantage of this known tight thread connection is that contact stresses in the seal cannot be high enough with such a radius of the toroidal sealing surface and no reliable seal is ensured during operation, which creates a risk of operating medium leakage and impairs the reliability of this connection.

The closest is the tight metal pipe thread connection, formed by threaded end areas with internal and external support conical threads of two coaxial pipes - outer and inner pipe, and by sealing and stop contact surfaces, the sealing surface of the outer pipe being conical, the sealing surface of the inner tube is toroidal, and the stop surfaces of the outer and inner tube are conical with a negative cone angle y to the plane perpendicular to the longitudinal axis X of the connection, the inner tube being equipped with an additional cylindrical surface, which has the toroidal sealing surface on the one hand and the threaded end area on the other [«THREADED TUBE JOINT» EP1540227B1, F16L15/06; 12/12/2007.

In the known threaded connection, the radius of the toroidal sealing surface is in the range of 30 to 100 mm, while the inner tube has a frustoconical contact surface at the front end area, which has an angle v of (-)15° to (-)5° to the longitudinal axis of the connection X vertical plane.

A disadvantage of this known connection is that the contact length "b" on the conical and toroidal sealing surface of the outer and inner tube is not more than 0.5 mm.

According to the calculations, the contact length of the sealing surfaces of the outer and inner tube should be at least 2 mm in order to ensure the tightness of the connection.

In addition, high contact stresses can arise in the known threaded connection, which can cause destruction of the contacting conical and toroidal sealing surfaces of the outer and inner tubes.

[0015] A disadvantage of the known technical solution is thus the low reliability caused by impaired tightness.

The object of the invention is to develop a tight threaded metal pipe connection, the use of which can contribute to operational reliability.

The technical task is solved as follows: in the sealed metal pipe thread connection, formed by threaded end areas, each with an inner and outer supporting conical thread, of two coaxial pipes - outer and inner pipe, and by sealing and stop contact surfaces, with the sealing surface of the outer pipe being conical the sealing surface of the inner tube is toroidal, and the stop surfaces of the outer and inner tube are conical with a negative cone angle y to the plane perpendicular to the longitudinal axis X of the connection, the inner tube being equipped with an additional cylinder surface which, on the one hand, has the toroidal sealing surface and on the other hand coupled with the threaded end area, according to the invention the toroidal sealing surface in the outer tube of the tube with an outer diameter of D = 4% - 13%" is designed with a radius R1 = 70-140mm, the inner tube having an additional conical surface with Cone angle @® of 25 - 35% to the connecting longitudinal axis X is equipped, which is coupled on the one hand with the toroidal sealing surface and on the other hand with the conical stop surface, and where

the outer tube with the conical sealing surface with a cone angle ß of B = @ (5) % for comparison

binding longitudinal axis X, and is designed with an inner ring groove lying between the threaded end area and the conical sealing surface.

Equipping the inner pipe with a toroidal sealing surface with a radius of Rı = 70 mm-140 mm for pipes with an outer diameter D = 4%" - 13%" allows to increase the contact surface on the conical and toroidal sealing surface of the outer and inner pipe .

The nominal overlap area ensuring a tight connection was calculated with the formula determined by the Applicant, which only includes geometric connection parameters:

S=2-m-D-Jar? ; (sin@)?] . [1 — (sin(9))2]

where: D - inner pipe diameter at the point of contact of sealing surfaces, in mm; R - radius of the toroidal sealing surface of the inner tube, in mm;

a - angle between the radius drawn to the center point of the overlap of the toroidal sealing surface of the inner tube and the radius drawn to the boundary point of the point of contact of the toroidal sealing surface of the inner tube and the conical sealing surface of the outer tube; in degrees (°);

9 - Angle between the plane of the conical sealing surface of the outer tube and the chord drawn from the boundary point of the point of contact of the toroidal sealing surface of the inner tube with the conical sealing surface of the outer tube to the center point of the overlap of the toroidal sealing surface of the inner tube, in degrees (° ).

In this case, the contact length b is: b=2 mm, with Rı=70 mm; b=7 mm, at Rı = 140 mm;

In this embodiment, contact stresses can arise in the threaded connection, which form a secure barrier for gas and liquid pressure, which enables a higher connection tightness and thereby reduces or eliminates the risk of destruction for touching conical and toroidal sealing surfaces of the outer and inner pipe.

Since the inner tube is designed with an additional conical surface with a cone angle € of 25%-35% to the connecting longitudinal axis X, which is coupled on the one hand with the toroidal sealing surface and with the conical stop surface, and with regard to the design

tion of the outer tube with the conical sealing surface with cone angle B from B = © CF ") % to

Connection longitudinal axis X, excess lubricant is expelled into the annular space between the conical surfaces.

Thus, the proposed tight threaded metal pipe connection ensures an elongation of the contact area b of the toroidal sealing surface of the inner pipe, which comes into contact with the conical sealing surface of the outer pipe, which increases the tightness of the threaded connection and its operational reliability.

The equipment of the inner tube with an additional conical surface and an additional cylindrical surface with the toroidal sealing surface or radius transitions with radius R; = 5.0 mm + 1.0 mm allows to avoid de-sealing of the connection in case of alternating stresses.

The conical design of the stop surfaces of the outer and inner tube with a negative cone angle (-)10°sv=(-)20° to the plane perpendicular to the longitudinal axis X of the connection makes it possible to reduce the negative effect of the notches and prevents the formation of turbulence the movement of the operating medium within the connection.

Equipping the outer tube with an inner ring groove with fillets with a radius of Ra=0.5 mm+0.1 mm reduces the negative effect of the inner angular notches of the ring groove and increases the strength of the inner tube.

The equipment of the outer tube with a conical sealing surface and conical stop surface with a radius transition with a radius of Ra = 0.9%? mm are coupled, as well as the equipment of the inner tube with an additional conical surface and conical stop surface, which have a radius transition with a radius of Rs = 1.0*%°? mm are coupled, can ensure optimal contact of the stop surfaces when screwing the tube and effective transfer of the torque and longitudinal forces in the tube column during assembly and operation.

The execution of the threaded end areas of the outer and inner tube with inner and outer support cone thread, in which the profile of the support cone thread has a negative angle a, au of (-)2° °5° on the wing and a positive angle as, as of (+)10° + 0.5° to the plane perpendicular to the longitudinal axis of the connection X on the insertion surface, enables multiple wear-free screwing and unscrewing of the tight threaded connection and also serves as a lock against possible slipping, which also contributes to the reliability of the threaded connection.

The invention is explained in more detail below using exemplary embodiments with reference to the drawings. It shows:

Figure 1 is an overall drawing of the sealed threaded metal pipe connection; Figure 2 shows a fragment of the outer tube of the sealed threaded metal pipe connection; Figure 3 shows a fragment of the inner pipe of the tight threaded metal pipe joint; Figure 4 shows a profile of the supporting conical thread of the inner tube;

Figure 5 represents a profile of the support cone thread of the outer tube; and

Figure 6 is a fragment of the contact area of the conical sealing surface of the outer tube.

A tight metal pipe thread connection is achieved by (Fig. 1) threaded end areas 1, 2, each with an inner and outer supporting conical thread 3 and 4, of two coaxially lying pipes - an outer and an inner pipe 5 and 6, sealing contact surfaces 7 and 8, and stop surfaces 9 and 10 formed.

The sealing surface 7 of the outer tube 5 is conical (Fig. 2). The sealing surface 8 of the inner tube 6 is designed in the shape of a torus (FIG. 3).

The abutment surfaces 9 and 10 of the inner and outer tubes 5 and 6 are conical with a negative cone angle γ to the plane perpendicular to the longitudinal axis X of the connection.

The inner tube 6 is equipped with an additional cylindrical surface 13 which is coupled to the toroidal sealing surface 8 on the one hand and to the threaded end area 2 on the other hand.

In the inner tube 6, the toroidal sealing surface 7 for the tube is mostly designed with an outside diameter of D=4%-13%" with a radius R1=70-140 mm.

The inner tube 6 is equipped with an additional conical surface 12 with a cone angle ε of 25-35% to the longitudinal connection axis X, which is coupled to the toroidal sealing surface 8 on the one hand and to the conical stop surface 10 on the other hand.

The outer tube 5 is provided with the conical sealing surface 7 with a cone angle B of = (5)

% to the connection longitudinal axis X and with an inner ring groove 11 located between the threaded end area 1 and the conical sealing surface 7 .

Such an embodiment of the tight metal pipe thread connection allows an extension of the contact surface b of the toroidal sealing surface 8 of the inner pipe 6, which comes into contact with the conical sealing surface 7, up to 2-7 mm, which significantly increases the tightness and operational reliability of the connection.

In the inner tube 6 are an additional conical surface 12 and an additional cylindrical surface 13 with the toroidal sealing surface 8 or radius transitions 14, 15 with a radius of R; = 5.0+1.0mm coupled.

In the outer tube 5 and inner tube 6, the stop surfaces 9 and 10 are conical with a negative cone angle v of (-)10°s v<=(-)20° to the plane perpendicular to the longitudinal axis X of the connection.

In the outer tube 5, the inner ring groove 11 is designed with grooves 16 with a radius of Rz3=0.5+0.1 mm.

In the outer tube 5, the conical sealing surface 7 and the conical stop surface 9 are coupled with a radius transition 17 with a radius of Ra=0.9%2mm.

In the inner tube 6 are the additional conical surface 12 and the conical stop surface 10 with radius transition 18 with a radius of Rs = 1.0 *%? mm coupled.

In the outer tube 5 and inner tube 6, the threaded end regions 1, 2 are provided with external and internal supporting conical threads 3, 4 with a cone angle α of 5.25-8.25% to the longitudinal axis X of the connection.

In the outer tube 5 and inner tube 6, the threaded end regions 1, 2 with the outer and inner supporting conical thread 3, 4 are designed in such a way that the supporting conical thread profile has a negative angle a», au of (-)2° 05° on the wing and has a positive angle as, as (+)10°+0.5° to the plane perpendicular to the connecting longitudinal axis X on the insertion surface (Fig. 4.5).

EXAMPLE.

The pattern design of the tight metal pipe thread connection is through the threaded end areas 1, 2, each with the internal and external supporting conical thread 3 and 4 of two coaxially lying pipes - the outer and inner pipe 5 and 6, the contacting sealing surfaces 7, 8, and the contacting Stop surfaces 9 and 10 7.8 and 9, 10 formed.

The sealing surface 7 of the outer pipe 5 was conical, the sealing surface 8 of the inner pipe 6 was toroidal, the stop surfaces 9 and 10 of the inner and outer pipe 5 and 6 were conical with a negative cone angle v to that of the connecting longitudinal axis X

executed in a vertical plane.

The inner tube 6 was equipped with an additional cylinder surface 13 which was coupled to the toroidal sealing surface 8 on the one hand and to the threaded end area 2 on the other hand. In the inner tube 6, the toroidal sealing surface 7 for the tube was mostly designed with an outside diameter of D=4%-13%" with a radius Rı = 70-140mm.

The inner pipe 6 was equipped with an additional conical surface 12 with a conical angle γ of 25-35% to the connecting longitudinal axis X, which was coupled to the toroidal sealing surface 8 on the one hand and to the conical stop surface 10 on the other.

The outer tube 5 was provided with a conical sealing surface 7 with a cone angle B of β=@(15)%

to the longitudinal axis of the connection X and with an inner annular groove 11 lying between the threaded end region 1 and the conical sealing surface 7 .

The nominal overlap area ensuring a tight joint was calculated with the formula determined by the Applicant, which only includes geometric joint parameters:

S=2- m: D- ler: . (sin@)?] [1 — (sin(0))2] =

°

1.3 2-3.14-330.48 - Je -1302- Gsin ( >

)»2] [1 — (sin(5%)2] = 6092mm“®

whereby:

D - inner pipe diameter at the point of contact of sealing surfaces, mm (D = 330.48 mm);

R - radius of the toroidal sealing surface of the inner tube, mm; (R = Rı = 130mm);

a - angle between the radius drawn to the center point of the overlap of the toroidal sealing surface of the inner tube and the radius drawn to the boundary point of the point of contact of the toroidal sealing surface of the inner tube with the conical sealing surface of the outer tube; degrees (°); (α = 2.25°);

9 - Angle between the plane of the conical sealing surface of the outer tube and the chord drawn from the boundary point of the point of contact of the toroidal sealing surface of the inner tube with the conical sealing surface of the outer tube to the center point of the overlap of the toroidal sealing surface of the inner tube, degrees (°) ; (8 = 42.75°).

In this case, the contact length b is:

At the same time, the sample design of the tight metal pipe threaded connection was made in accordance with the valid regulations for thread type buttress with the following geometric parameters: nominal outer diameter of the inner pipe - 339.725 mm; Nominal outer diameter of the outer tube - 36241 mm; Radius of the sealing surface of the inner tube is Rı = 130+0.5 mm; Thread pitch angle is a1= 6.25%+40.1%; The cone angle of the sealing surfaces of the inner and outer pipe is y = -15° to the plane perpendicular to the longitudinal axis X of the connection; Cone angle of the additional cone surface of the inner tube is € = 15°+0.5; The cone angle of the cone-shaped sealing surface of the outer tube is Bß = 30%+40.1% to the longitudinal connection axis X (16.67°+0.05°); The radius of the fillets from the inner ring groove of the outer tube is R3 = 0.5 mm; Radius transitions in the couplings of the additional cylinder surface of the inner tube with

the toroidal sealing surface and the additional conical surface of the inner tube with the toroidal surface are R2= 5 mm. The tight metal pipe thread connection works as follows.

When screwing and unscrewing the threaded connection, the threaded end regions 1, 2 interact with the inner and outer supporting conical threads 3 and 4 of the outer tube 5 and inner tube 6.

Due to the diametrical elastic deformations of the above-mentioned sealing surfaces 7, 8, a "metal - metal" sealing element of the "cone - torus" type, which ensures a contact length b of 2-7 mm, is created in that the toroidal sealing surface 8 with a radius of Rı = 70-140 mm.

In this way, the contact stresses arise in the connection, which create a reliable barrier for gas and liquid pressure and ensure high tightness of the connection, but do not cause the sealing surfaces 7 and 8 in contact to be destroyed.

Since the inner pipe 6 is equipped with an additional conical surface 12 with a cone angle γ of 25 - 35% to the connecting longitudinal axis X, which is coupled on the one hand with a toroidal sealing surface 8 and on the other hand with a conical stop surface 10, and the outer pipe 5 is equipped with a conical

Sealing surface 7 with a cone angle ß of ß = (5) % to the longitudinal axis X of the connection is made

excess lubricant is expelled into the annular space between the conical surfaces, which ensures tightness and operational reliability of the connection.

The inner annular groove 11 of the inner tube 6, which lies between the threaded end portion 1 and the conical sealing surface 7, creates an annular space for collecting the lubricant, which ensures tightness of the connection.

During the further screwing of the threaded end area 1 with the inner cone supporting thread 3 of the outer pipe 5 onto the threaded end area 2 with the outer cone supporting thread 4 of the inner pipe 6, a force contact of the conical stop surface 9 of the outer pipe 5 with the conical stop surface 10 of the inner pipe 6 occurs, which is connected to a negative cone angle v of (-)10°sy = (-)20° to the plane perpendicular to the longitudinal axis X of the connection.

As a result, contact stresses in the area of the elastic deformations arise on the conical abutment surface 9 of the outer tube 5 with the conical abutment surface 10 of the inner tube 6.

During the interaction of the conical stop surface 9 of the outer tube 5 with the conical stop surface 10 of the inner tube 6, which lie with the negative cone angle y of (-)10°sv = (-)20° to the plane perpendicular to the longitudinal axis X of the connection, and at the effect of the axial load on which arises during the screwing of the outer pipe 5 and inner pipe 6, the transverse component of this load is directed to the longitudinal axis X of the connection, which increases the tightness and operational reliability of the connection.

Thus, the use of the tight threaded metal pipe connection allows to increase the tightness and operational reliability of the connection, while not requiring great effort in manufacture and assembly, so this connection can be used extensively in the construction of gas and oil wells.

Claims (8)

Expectations 1. Tight metal pipe thread connection, formed by threaded end areas, each having an internal supporting conical thread and an external supporting conical thread of two coaxially lying tubes, namely an outer tube (5) and an inner tube (6), and by sealing and abutment contact surfaces, wherein a sealing surface (7) of the outer tube ( 5) is conical, with a sealing surface (8) of the inner pipe (6) being toroidal, with the stop surfaces (9, 10) of the outer and inner pipe (5, 6) being conical and with a negative cone angle, y, to the are designed in a plane perpendicular to the longitudinal axis (X) of the connection, the inner tube (6) being equipped with an additional cylindrical surface (13) which is coupled on the one hand to that of the toroidal sealing surface (8) and on the other hand to the threaded end region (2), characterized in that that the toroidal sealing surface (7) in the outer tube (5) of the tube with an outer diameter of D = 4% - 13%" has a radius Rı = 70-14 0mm, the inner tube (6) being equipped with an additional conical surface (12) with a conical angle, ©, of 25 - 35% to the connecting longitudinal axis (X), the additional conical surface (12) on the one hand being in contact with the toroidal sealing surface (8) and on the other hand is coupled to the conical stop surface (10) of the inner tube (6), the outer tube (5) having the conical sealing surface (7) with conical angle, B, from = @ (5) % to the connection longitudinal axis (X), as well as with between the Windeendbereich (1) and the conical sealing surface (7) lying inner annular groove (11) is executed. 2. Tight metal pipe thread connection according to claim 1, characterized in that the additional conical surface (12) and an additional cylindrical surface (13) in the inner pipe (6) with the toroidal sealing surface (8) or with radius R2 = 5.0 mm + 1, 0 mm or tangentially executed radii transitions (14 and 15) are coupled. 3. Tight metal pipe thread connection according to claim 1 or 2, characterized in that the stop surfaces (9, 10) in the outer and inner pipe (5, 6) are conical with a negative cone angle v of (-) 10 ° sv = (-) 20° to the plane perpendicular to the longitudinal axis of the connection (X). 4. Tight metal pipe thread connection according to one of claims 1 to 3, characterized in that the inner ring groove (11) in the outer pipe (5) is designed with grooves (16) with a radius of R3 = 0.5 mm + 0.1 mm. 5. Tight metal pipe thread connection according to one of claims 1 to 4, characterized in that the conical sealing surface (7) and the conical stop surface (9) in the outer pipe (5) with a radius transition (17) with a radius of Rı = 0.9% ? mm are coupled. 6. Tight metal pipe thread connection according to one of claims 1 to 5, characterized in that the additional conical surface (12) and the conical stop surface (10) in the inner pipe (6) with a radius transition (18) with a radius of Rs = 1.0* °% mm are coupled. 7. Tight metal pipe thread connection according to one of claims 1 to 6, characterized in that the threaded end areas (1, 2) of the outer and inner pipe (5, 6) with outer and inner support conical thread (3, 4) correspondingly with cone angle a of 5, 25% - 8.25% to the longitudinal axis of the connection (X). 8. Tight threaded metal pipe connection according to one of claims 1 to 7, characterized in that the threaded areas (1, 2) of the outer and inner pipe (5, 6) with inner and outer supporting conical threads (3, 4) are designed accordingly in such a way that the supporting conical thread profile has a negative angle a»,au of (-)2° 0° on the wing and a positive angle a3,as(+)10°+0.5° on the plane perpendicular to the connecting longitudinal axis (X) on the insert surface. 4 sheets of drawings