CN112393036A

CN112393036A - Connecting method of pipeline joint

Info

Publication number: CN112393036A
Application number: CN202011252268.6A
Authority: CN
Inventors: 朱旭林
Original assignee: Hunan Tianli Ruijia New Material Technology Co ltd
Current assignee: Hunan Tianli Ruijia New Material Technology Co ltd
Priority date: 2020-11-11
Filing date: 2020-11-11
Publication date: 2021-02-23
Anticipated expiration: 2040-11-11
Also published as: CN112393036B

Abstract

A connecting method of a pipeline joint comprises at least one external O-shaped ring, at least one metal connector, a metal joint main body and at least one metal wedge cap, wherein the connector and the joint main body are mutually connected; the radial inner wall of the connector is integrally provided with an annular bulge protruding towards the central axis direction of the pipeline connector, and the wedging cap can be sleeved on the radial outer side of the joint end of the connector; the connecting method of the pipeline joint comprises the following steps: the wedging cap is locked towards the axial end part where the connector of the pipeline joint is positioned by means of force application of a tool, and the annular bulge is inwards pressed on the outer wall of the end part of the metal pipeline to form a first defense line for connecting and sealing the pipeline joint and the metal pipeline; the connection method provided by the invention has good sealing effect; the corresponding pipeline joint product is light, and the raw material cost is greatly saved; the wedging cap cannot fall off before installation, and the installation is convenient; and the overall test performance of the pipeline joint is very good.

Description

Connecting method of pipeline joint

Technical Field

The invention belongs to the field of pipeline connecting pieces, and particularly relates to a pipeline joint for connecting metal pipelines and a connecting method thereof.

Background

The existing metal fittings for connecting metal water pipes generally comprise two generations of products. In the first generation of joint products, the sealing structure for preventing water leakage is a rubber sealing ring, and belongs to a soft sealing structure. The sealing ring in the product is easy to age and damage, and easily releases toxin at high temperature, thus being not environment-friendly. The connection mode of the second generation joint product and the metal water pipe is clamping and pressing type, compaction and sealing, and belongs to a hard sealing structure. The second generation products need to be sealed by filling materials such as polytetrafluoroethylene and the like during installation, so that the use is inconvenient.

For example, chinese patent CN201921339260 provides a sealing connection structure of a pipe, which includes a connector arranged outside the pipe, the end of the connector is provided with a plurality of sealing rings at intervals, an inner annular surface of each sealing ring is provided with a pressure reducing inclined surface, and the inclination directions of the pressure reducing inclined surface and the pressure reducing inclined surface are kept consistent; a locking cap is arranged outside the connecting piece, and a clamp point convex ring for applying clamping force to hydraulic pressure is formed on the outer surface of the middle end part of the connecting piece; the locking cap is characterized in that a horn-shaped flaring structure is formed in one end of the locking cap, the pipe is located in the connecting piece in a preassembly state, an outer port of the flaring structure of the locking cap is in contact with the connecting piece, when the hydraulic pliers exert force and act on the locking cap and the pliers point convex ring at the same time, the connecting piece is extruded into the locking cap after passing through the flaring structure of the locking cap to form a connecting and sealing structure between the connecting piece and the pipe. The invention has high connection strength, good sealing effect and long service life; the whole connecting structure is stable, the machining procedures are few, the machining precision requirement is low, and the machining cost is greatly reduced.

However, the joint provided by this patent does not solve the problem of caulking by ptfe and the joint still requires two people to install successfully.

Accordingly, there is a need in the art to provide a new pipe joint and a new joining method to solve the above problems.

Disclosure of Invention

Therefore, the invention provides a connecting method of a pipeline joint, the pipeline joint is used for being connected with at least one metal pipeline, the pipeline joint comprises at least one external O-shaped ring (1), at least one metal connector (2), a metal joint main body (3) and at least one metal wedge cap (4), the external O-shaped ring (1) is used for connecting and sealing the pipeline joint and the metal pipeline, and the connector (2) and the joint main body (3) are connected with each other; the joint head (2) comprises a joint end (21) and a pipeline end (22), the joint body (3) comprises a body end (31) and at least one inner joint end (32), the body end (31) is used for connecting the pipeline joint with a water faucet or other workpieces, or the body end (31) is used for connecting a plurality of inner joint ends (32), and the inner joint end (32) is used for being connected and matched with the joint end (21); an annular bulge protruding towards the central axis direction of the pipeline joint is integrally arranged on the radial inner wall of the connector (2), the wedging cap (4) can be sleeved on the radial outer side of the joint end (21) of the connector (2), and the thickness of the wedging cap (4) is larger than that of the connector (2); the outer wall of the connector (2) comprises at least one slope surface (23), the slope surface is a conical table top with a large outer diameter close to the pipeline end (22) and a small outer diameter close to the joint end (21), an inclined tightening surface matched with the slope surface (23) is arranged on the inner wall of the wedging cap (4), and the inclined tightening surface is also a conical table top with a large inner diameter at one end and a small inner diameter at the other end; the slope surface (23) and the slope tightening surface are matched for the wedge cap (4) to smoothly slide from the joint end (21) to the pipeline end (22) and enable the pipeline joint to lock the pipeline at the end;

the connecting method of the pipeline joint comprises the following steps: the wedging cap is locked to the axial end part where the connector (2) of the pipeline connector is located by means of tool force application, the annular protrusion is inwards pressed on the outer wall of the end part of the metal pipeline under the matching of the slope surface (23) and the inclined tight surface to form a first defense line for connecting and sealing the pipeline connector and the metal pipeline, and the external O-shaped ring (1) is arranged at the axial outer end of the annular protrusion, namely arranged on the pipeline connector and close to the tail end of the connector (2) to form a second defense line for connecting and sealing the pipeline connector and the metal pipeline in the axial direction of the pipeline connector;

when the other workpieces connected with the main body end (31) are also metal pipelines, the radial inner wall of the joint main body (3) is also integrally provided with an annular bulge protruding towards the central axis direction of the pipeline joint, the outer wall of the joint main body (3) comprises at least one inclined surface, the inclined surface is a conical table surface which is close to the main body end (31) and has a large outer diameter and a small outer diameter and is close to the inner connection end (32), the inner wall of the wedge cap (4) matched with the joint main body (3) is also provided with an inclined tight surface matched with the inclined surface, and the inclined tight surface is also a conical table surface which has a large inner diameter at one end and a small inner diameter at the other end; the connecting method of the pipe joint further comprises: make with the help of instrument application of force the wedging cap is to the axial tip locking at the joint main part (3) place of pipe joint, cyclic annular arch inwards oppresses on the outer wall of metal pipeline tip, form the pipe joint is connected with metal pipeline and sealed first line defence line, and in the axis direction of pipe joint, external O type circle (1) sets up cyclic annular bellied axial outer end sets up the end that is close to joint main part (3) on pipe joint promptly, forms the pipe joint is connected with metal pipeline and sealed second way defence line.

In a particular embodiment, the connection of the inner joint end (32) and the joint end (21) is a threaded connection; when the pipeline joint is preferably installed, firstly, anti-skid glue is coated on the external threads in the inner joint end (32) and the joint end (21) to prevent the threads from retreating, so that the sealing connection in the pipeline joint is realized.

In a specific embodiment, the pipeline joint comprises an external O-shaped ring (1), a metal connector (2), a metal joint main body (3) and a metal wedge cap (4), wherein the main body end (31) is a workpiece end for connecting the pipeline joint with a water faucet or other workpieces, and the workpiece end is provided with internal threads or external threads for connecting with the workpieces.

In a particular embodiment, the engagement end (21) is a small diameter end of the outer diameter of the connector (2), the conduit end (22) is a large diameter end of the outer diameter of the connector (2), the small diameter end includes a cylindrical outer diameter surface a1, the large diameter end includes a cylindrical outer diameter surface a2, and the ramp surface (23) is disposed between the two cylindrical outer diameter surfaces.

In a particular embodiment, each coupling head (2) comprises at least two annular projections on its inner wall, and the two annular projections are arranged one behind the other in the axial direction of the pipe coupling.

In a particular embodiment, the coupling end (21) of the connection head (2) comprises an internal or external thread and, correspondingly, the inner end (32) of the joint body (3) comprises an external or internal thread.

In a particular embodiment, the pipe end (22) of the coupling head (2) is provided with a stop shoulder a (24) for preventing the wedging cap (4) from disengaging from the pipe coupling from the end in the axial direction.

In a particular embodiment, the wedging cap (4) is arranged to be slidable in the axial direction of the pipe joint radially outside the coupling head (2) and the coupling body (3) when the pipe joint is not installed.

In a particular embodiment, the pipe joint further comprises an auxiliary seal (5), the auxiliary seal (5) being used for connection and sealing of the pipe joint internal components.

In a specific embodiment, when the threads of the joint end (21) and the inner joint end (32) are screwed into place, a planar axial end surface A at the joint end (21) and a planar axial end surface B at the inner joint end (32) are jointed to form an annular butt-joint surface, and the auxiliary sealing element (5) is arranged on the radial inner side of the annular butt-joint surface.

In a particular embodiment, the secondary seal (5) is an inscribed O-ring or metal gasket.

The invention has at least the following beneficial effects:

1) the sealing effect is good: the pipeline joint product disclosed by the invention is mainly sealed by hard sealing and assisted by soft sealing of the O-shaped ring, polytetrafluoroethylene is not required for joint filling in the installation process, the installation is more convenient, the sealing effect is better, and meanwhile, the product performance is stronger.

2) The pipeline joint product corresponding to the connecting method is light, and the raw material cost is greatly saved.

3) The wedging cap can not fall off before installation, and the installation is convenient.

4) During installation, the end part of the metal pipeline cannot fall off from the joint, and the number of installation workers is saved.

5) The overall test performance of the pipe joint is very good. The detection data of the drawing test, the limit pressure-bearing test and the like exceed the national standard by more than several times.

In general, the invention adopts a soft and hard seal combination mode for the first time, wherein the hard seal belongs to a riveting process between metals, thereby avoiding plastic filling and solving the problem of hidden water leakage caused by aging of plastic or rubber sealing rings; wherein soft seal can ensure the product at first and further ensure the sealing stability of product when the deformation is bent in the transition, promotes the factor of safety of water pipe to the safety of guarantee water. And the soft seal can correspondingly save the labor amount for installing the joint. In addition, the sealing direction of the hard seal is very characteristic, so that the consumption of raw materials of the pipeline joint is reduced.

Drawings

Fig. 1 is a perspective view showing an exploded structure of the pipe joint according to the present invention (an internal thread through joint).

Fig. 2 is a front view of the structure of the pipe joint of the present invention before installation (inner wire straight joint).

Fig. 3 is a front sectional view (female-wire through-joint) of the structure of the present invention before the pipe joint is installed.

Fig. 4 is a perspective view of the structure of the pipe joint of the present invention before installation (female-wire straight joint).

Fig. 5 is a perspective view of a structure before the pipe joint of the present invention is installed (tee joint).

Fig. 6 is a perspective view showing an exploded structure of the pipe joint according to the present invention (tee joint).

Fig. 7 is a perspective view (elbow connector) of the pipe joint of the present invention before installation.

Fig. 8 is a perspective view of the structure of the pipe joint of the present invention before installation (equal diameter straight joint).

In the figure: 1. the sealing device comprises an external O-shaped ring 2, a connector 3, a connector main body 4, a wedging cap 5 and an auxiliary sealing element.

Detailed Description

As shown in fig. 1 to 8, the present invention specifically provides a method for connecting a pipe joint, where the pipe joint is used to connect at least one metal pipe, the pipe joint includes at least one external O-ring (1), at least one metal connector (2), a metal joint main body (3), and at least one metal wedge cap (4), the external O-ring (1) is used to connect and seal the pipe joint and the metal pipe, and the connector (2) and the joint main body (3) are connected to each other; the joint head (2) comprises a joint end (21) and a pipeline end (22), the joint body (3) comprises a body end (31) and at least one inner joint end (32), the body end (31) is used for connecting the pipeline joint with a water faucet or other workpieces, or the body end (31) is used for connecting a plurality of inner joint ends (32), and the inner joint end (32) is used for being connected and matched with the joint end (21); an annular bulge protruding towards the central axis direction of the pipeline joint is integrally arranged on the radial inner wall of the connector (2), the wedging cap (4) can be sleeved on the radial outer side of the joint end (21) of the connector (2), and the thickness of the wedging cap (4) is larger than that of the connector (2); the outer wall of the connector (2) comprises at least one slope surface (23), the slope surface is a conical table top with a large outer diameter close to the pipeline end (22) and a small outer diameter close to the joint end (21), an inclined tightening surface matched with the slope surface (23) is arranged on the inner wall of the wedging cap (4), and the inclined tightening surface is also a conical table top with a large inner diameter at one end and a small inner diameter at the other end; the slope surface (23) and the slope tightening surface are matched for the wedge cap (4) to smoothly slide from the joint end (21) to the pipeline end (22) and enable the pipeline joint to lock the pipeline at the end; the connecting method of the pipeline joint comprises the following steps: the wedging cap is locked to the axial end part where the connector (2) of the pipeline connector is located by means of tool force application, the annular protrusion is inwards pressed on the outer wall of the end part of the metal pipeline under the matching of the slope surface (23) and the inclined tight surface to form a first defense line for connecting and sealing the pipeline connector and the metal pipeline, and the external O-shaped ring (1) is arranged at the axial outer end of the annular protrusion, namely arranged on the pipeline connector and close to the tail end of the connector (2) to form a second defense line for connecting and sealing the pipeline connector and the metal pipeline in the axial direction of the pipeline connector; when the other workpieces connected with the main body end (31) are also metal pipelines, the radial inner wall of the joint main body (3) is also integrally provided with an annular bulge protruding towards the central axis direction of the pipeline joint, the outer wall of the joint main body (3) comprises at least one inclined surface, the inclined surface is a conical table surface which is close to the main body end (31) and has a large outer diameter and a small outer diameter and is close to the inner connection end (32), the inner wall of the wedge cap (4) matched with the joint main body (3) is also provided with an inclined tight surface matched with the inclined surface, and the inclined tight surface is also a conical table surface which has a large inner diameter at one end and a small inner diameter at the other end; the connecting method of the pipe joint further comprises: make with the help of instrument application of force the wedging cap is to the axial tip locking at the joint main part (3) place of pipe joint, cyclic annular arch inwards oppresses on the outer wall of metal pipeline tip, form the pipe joint is connected with metal pipeline and sealed first line defence line, and in the axis direction of pipe joint, external O type circle (1) sets up cyclic annular bellied axial outer end sets up the end that is close to joint main part (3) on pipe joint promptly, forms the pipe joint is connected with metal pipeline and sealed second way defence line.

Before the pipeline joint is installed, under the condition that the wedging cap is separated from the pipeline joint in the prior art, the diameter of the cylindrical outer diameter surface A2 is larger than that of the cylindrical outer diameter surface A1, and the blocking shoulder is further designed, so that the wedging cap in the transportation process is kept in the axial middle of the pipeline joint, and the problem that the wedging cap falls off and slides out of the pipeline joint is solved in design. The pipeline joint product can be integrally thrown before installation and cannot be scattered. Therefore, the transportation is more convenient, and the installation is also more convenient.

In the invention, the materials of the metal pipeline and the metal joint can be selected from stainless steel, copper or cast iron freely.

According to the invention, the sealing connection between the components inside the pipeline joint depends on the threaded connection between the connector (2) and the joint main body (3), and glue can be applied to the external threads of the connector (2) or the joint main body (3) during the installation of the pipeline joint, and the internal sealing of the joint can be prevented from leaking by screwing the connector (2) and the joint main body (3) during the installation. Of course, the connection mode of the auxiliary sealing member can be used instead of applying glue.

The invention provides a third generation metal joint product which does not need polytetrafluoroethylene when being connected with a metal water pipe.

The invention is at least distinguished from patent CN201921339260 as follows: the wedge cap 4 of the present invention is disposed at an axially intermediate position of the pipe joint, which is located axially intermediate the coupling head 2 and the joint body 3. That is to say the wedge cap 4 of the present invention is arranged axially inside, while the locking cap 1 of patent CN201921339260 is arranged at the axial end of the joint. Secondly, because the structures of the two pipe joints are different, the two pipe joints are different in installation mode when being installed. In particular, patent CN201921339260 is a device in which the locking cap 3 is moved in the axial direction gradually closer to the axial center position of the joint, i.e. away from one end of the connector 2, to squeeze the connector 2 and lock the pipe. The invention is that the wedging cap 4 moves away from the central point of the pipe joint gradually in the axial direction, namely moves close to one end of the joint 2 to press the joint 2, thereby locking the pipe.

In addition, the invention has at least the following characteristics:

1) sealing the joint and the pipeline: the first seal is a hard seal, and particularly comprises two metal rings which protrude inwards from the radial inner side wall of the connector (2) and are arranged in the axial direction of the connector in a front-back mode. The second seal is a soft seal, in particular to an O-shaped ring arranged on the outer side of the joint shaft of the metal ring, namely the external O-shaped ring (1). Therefore, the external O-shaped ring (1) only plays a role of safety, and generally cannot contact liquid in a pipeline, so that the service life of the external O-shaped ring is greatly prolonged. The external O-shaped ring (1) has other two functions, one function is that when the pipeline is bent within 30 degrees for installation, the original hard seal is easy to lose efficacy, and at the moment, the external O-shaped ring (1) plays a main sealing effect. The other is that when the joint is installed on the pipeline, the external O-shaped ring (1) has elasticity, the end part of the pipeline is inserted into the joint to form friction with the O-shaped ring, and the pipeline can be effectively prevented from slipping out to fall outside the joint, so that the pipeline joint can be installed by only one worker.

3) The structure of the joint determines different mounting modes: the connection mode of the joint and the metal pipeline in the prior art is to push the joint from the axial end position of the joint to the axial center position of the joint, namely to the end far away from the connecting head 2, for example, the installation mode in patent CN 201921339260. The joint and the metal pipeline are connected in a mode of pulling from the center position of the joint to the axial end position of the joint, namely pulling towards one end close to the connector 2, specifically, pulling the wedging cap 4 by using a tool. In particular, the locking cap of the prior art joint requires the use of a mounting tool for guidance, whereas the wedging cap of the present invention is guided by a structure inside the joint itself, in particular by the outer wall surface of the joint head (2). The inner wall of the wedge cap 4 is matched to the outer wall of the connection head 2 at least over a certain axial length. In addition, the use of an external O-shaped ring is adopted, so that the connector can be installed only by one person. When the existing pipeline joint is installed, one person needs to hold the pipeline joint by hand, and the other person operates a tool to assemble the joint.

4) The difference of product structure and installation mode makes the total length of the pipeline joint of the invention shorter, saves materials: because the installation mode is changed, the axial direction is changed from outside to inside to the axial direction from inside to outside during installation, and the pipeline joint product can be shorter under the condition of the same sliding stroke of the two products. For example, the pipe joint product with the same application and the same thickness can reduce the total weight of DN20 pipe joint by 13% to 37% because the axial size of the joint is shortened. That is, the joint product of the present invention can significantly save raw material cost without sacrificing any product performance.

Common performance tests for water pipe joints include the following:

1. and (3) drawing test: the drawing test is used for detecting the drawing resistance of the pipe connection, and the stronger the drawing resistance is, the stronger the resistance of the water pipe to external force damage in actual use is. The test mode is that a thin-wall metal pipe with the length of 300mm is connected to the end part of the pipeline joint to form a group of samples, and the samples are fixed on a tensile testing machine. In the drawing test, the sample was drawn at a speed of 2mm/min, and the maximum drawing force at the time of breaking the sample was measured. The minimum tensile resistance of the pipe fitting specified in GB/T19228.1-2011, such as a joint with a nominal diameter DN20, is 3.46 KN; a joint with nominal diameter DN50 and minimum tensile resistance of 9.72 KN; the nominal diameter DN100 has a minimum tensile resistance of 35 KN.

Through detection, the minimum tensile resistance of the constant-diameter straight-through pipeline joint with the nominal diameter DN20 shown in figure 8 can reach more than 6 KN.

2. Vibration test: the water pipe vibration test is to simulate the damage influence of the shake and vibration of the water pipe connector on the water pipe under the action of a water hammer. GB/T19228.1-2011 states: the joint was connected to a pipe material having a length of 500mm or more to form a sample, and the sample was sealed with a water pressure of 1.7MPa therein and continuously vibrated 100 ten thousand times without leakage, falling off, and other abnormalities. Wherein the specified vibration conditions are that the amplitude is within plus or minus 2.5mm and the vibration frequency is 600 times per minute.

Through detection, the constant-diameter straight-through pipeline joint with the nominal diameter DN20 shown in figure 8 provided by the invention does not have any abnormality after continuously vibrating for more than 120 thousands of times.

3. Hydraulic bending angle test: the bending performance of pipe connection is detected, the larger the bending angle is, and the stronger the external force damage resistance of the water pipe in actual use is. GB/T19228.1-2011 stipulates that a joint is connected with a pipe with the length of more than 800mm to form a sample, clean water is injected into the sample to increase the pressure to 1.7MPa, the mouth of the pipe fitting of the sample is loaded, and the sample is bent to the appointed requirement without leakage, falling off or other abnormalities. The requirement of the bending angle of the joint of the nominal diameter DN20 is 30 degrees; the requirement of the bending angle of the joint of the nominal diameter DN50 is 20 degrees; the requirement of the bending angle of the connector with the nominal diameter DN100 is 15 degrees.

Through detection, the bending angle of the constant-diameter straight-through pipeline joint with the nominal diameter DN20 as shown in FIG. 8 can reach 35 degrees.

4. And (3) limit pressure-bearing test: the sample containing the water pipe and the joint was filled with water and the ultimate pressure that the sample could withstand was tested. GB/T19228.1-2011 specifies a connector with a nominal diameter DN20, and the ultimate pressure to be borne by the connector is 2.5 MPa.

Through detection, the constant-diameter straight-through pipeline joint with the nominal diameter DN20 shown in figure 8 can bear the limiting pressure of more than 10 MPa.

As can be seen from the above tests, the test performance of the pipe joint provided by the invention obviously exceeds the national standard. The pipeline joint has longer service life and safer use.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions and substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims

1. A method for connecting a pipeline joint, wherein the pipeline joint is used for being connected with at least one metal pipeline and comprises at least one external O-shaped ring (1), at least one metal connector (2), a metal joint main body (3) and at least one metal wedge cap (4), the external O-shaped ring (1) is used for connecting and sealing the pipeline joint and the metal pipeline, and the connector (2) and the joint main body (3) are connected with each other; the joint head (2) comprises a joint end (21) and a pipeline end (22), the joint body (3) comprises a body end (31) and at least one inner joint end (32), the body end (31) is used for connecting the pipeline joint with a water faucet or other workpieces, or the body end (31) is used for connecting a plurality of inner joint ends (32), and the inner joint end (32) is used for being connected and matched with the joint end (21); an annular bulge protruding towards the central axis direction of the pipeline joint is integrally arranged on the radial inner wall of the connector (2), the wedging cap (4) can be sleeved on the radial outer side of the joint end (21) of the connector (2), and the thickness of the wedging cap (4) is larger than that of the connector (2); the outer wall of the connector (2) comprises at least one slope surface (23), the slope surface is a conical table top with a large outer diameter close to the pipeline end (22) and a small outer diameter close to the joint end (21), an inclined tightening surface matched with the slope surface (23) is arranged on the inner wall of the wedging cap (4), and the inclined tightening surface is also a conical table top with a large inner diameter at one end and a small inner diameter at the other end; the slope surface (23) and the slope tightening surface are matched for the wedge cap (4) to smoothly slide from the joint end (21) to the pipeline end (22) and enable the pipeline joint to lock the pipeline at the end;

2. The method of connecting a pipe joint according to claim 1, wherein the coupling means of the inner joint end (32) and the joint end (21) is a threaded connection; when the pipeline joint is preferably installed, firstly, anti-skid glue is coated on the external threads in the inner joint end (32) and the joint end (21) to prevent the threads from retreating, so that the sealing connection in the pipeline joint is realized.

3. The method of connecting a pipe joint according to claim 1, wherein the engagement end (21) is a small diameter end of the outer diameter of the coupling head (2), the pipe end (22) is a large diameter end of the outer diameter of the coupling head (2), the small diameter end includes a cylindrical outer diameter surface a1, the large diameter end includes a cylindrical outer diameter surface a2, and the ramp surface (23) is provided between the two cylindrical outer diameter surfaces.

4. The method of connecting pipe joints according to claim 1, wherein each joint head (2) comprises at least two annular projections on its inner wall, and the two annular projections are arranged one behind the other in the axial direction of the pipe joint.

5. The method of connecting pipe joints according to any one of claims 1 to 4, wherein the joint end (21) of the joining head (2) comprises an internal or external thread, and correspondingly the inner joint end (32) of the joint body (3) comprises an external or internal thread.

6. Method for connecting a pipe joint according to any one of claims 1 to 4, wherein the pipe end (22) of the joining head (2) is provided with a shoulder A (24) for preventing the wedging cap (4) from coming off the pipe joint from the end in the axial direction.

7. A method of connecting a pipe joint according to any one of claims 1 to 3, wherein the wedge cap (4) is provided so as to be slidable in the axial direction of the pipe joint on the radially outer side of the coupling head (2) and the joint body (3) when the pipe joint is not installed.

8. The method of connecting a pipe joint according to claim 2, wherein the pipe joint further comprises an auxiliary seal (5), the auxiliary seal (5) being used for connection and sealing of the pipe joint inner member.

9. The method of connecting a pipe joint according to claim 8, wherein when the threads of the joint end (21) and the box end (32) are screwed into place, a planar axial end surface a at the joint end (21) and a planar axial end surface B at the box end (32) are brought into abutment to form an annular abutment surface, the auxiliary seal (5) being disposed radially inside the annular abutment surface; preferably, the auxiliary sealing element (5) is an inscribed O-shaped ring.