KR102344487B1 - Coated steel pipe connection structure with divided socket ring and pipe end protective cap - Google Patents

Abstract

The present invention provides a pipe end protection cap which is coupled to a pipe end region of a clad steel pipe and safely protects the pipe end region whose end surface is exposed without a coating material or is coated with the coating material from the outside. In addition, the present invention provides a clad steel pipe connection structure, by including the pipe end protection cap, which may actively prevent damage (e.g., peeling) due to the inner or outer coating of the other clad steel pipe being stamped on the pipe end of one of the clad steel pipes in the process of connecting the clad steel pipes to each other by inserting the same.

Description

COATED STEEL PIPE CONNECTION STRUCTURE WITH DIVIDED SOCKET RING AND PIPE END PROTECTIVE CAP}

An embodiment of the present invention relates to a cap used to protect the end of a tube, and a structure for connecting two tubes to each other.

Pipes for the purpose of transporting fluids such as water, sewage, gas, crude oil, etc., or pipes for accommodating cables such as electric wires and communication lines, may be used in cast-iron pipes or synthetic resin pipes. In comparison, a lot of steel pipes with excellent mechanical properties and light weight are used.

In general, a steel pipe is used as a coated steel pipe in which a coating material having excellent corrosion resistance and adhesion is applied to the inner and outer surfaces. Therefore, the coated steel pipe includes a steel pipe and a coating layer, and as a coating layer for protecting the steel pipe from the outside, it may include an inner surface coating and an outer surface coating coated on the inner and outer peripheral surfaces of the steel pipe, respectively. Such a coated steel pipe may further include an end face coating coated on the end face of the pipe end area in a separate process from the inner and outer surface coating coating process, but the importance occupied by the end face coating is lower than that of the inner and outer surface coating. Due to the relatively poor quality of the coating, the narrow area of the end face of the end face, etc., the end face coating may be easily lifted or torn and peeled off, thereby preventing the end face of the end face from protecting the end face from the outside Physical and chemical damage (eg corrosion) can easily occur.

On the other hand, the clad steel pipes may be connected to each other in an inserting manner. Therefore, if the end surface of the tube end area is not covered or the end surface coating is peeled off and the end surface of the tube end area is exposed, when the coated steel pipes are inserted and connected, the sharp edge of the end surface of the tube end area may be exposed to the inner or outer surface of another coated steel pipe. The coating can be engraved and damage the inner or outer coating.

Republic of Korea Patent Publication No. 10-1037586 (2011.05.27.) Republic of Korea Patent Publication No. 10-1924450 (2018.12.03.) Republic of Korea Patent Publication No. 10-2095325 (2020.03.31.)

An embodiment of the present invention is to provide a pipe end protection cap for a coated steel pipe that can safely protect the end surface of the pipe end area exposed or coated with a coating material from the outside, and a pipe connection structure including the same.

An embodiment of the present invention provides a pipe end protection cap for a coated steel pipe that can prevent damage due to an inner coating or an outer coating being stamped on the pipe end in the process of connecting the coated steel pipes to each other by the insertion method, and a pipe connection structure including the same would like to provide

The problem to be solved is not limited thereto, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention, the cap body (cap body) in the shape of a pipe (pipe) shape to be inserted into the pipe end region of the coated steel pipe is fixed; The end protection cap may be provided at the rear end of the cap body, including a ring-shaped cap head that covers and protects the exposed end surface of the tube end region.

The cap body may have a tip portion having an outer periphery larger than an inner periphery of the tube end region, and a cutout portion for inducing a reduction deformation of the tip portion within an elastic range may be formed on the tip portion. Accordingly, when the cap body is inserted into the tube end region, the outer periphery of the tip portion may be in close contact with the inner periphery of the tube end region so that the position of the cap body may be fixed.

The cap body may have at least one or more spikes protruding from an outer periphery between the front end portion and the rear end portion and embedded in the inner periphery of the tube end region.

Here, the spikes of the cap body may be formed in a closed ring shape.

According to an embodiment of the present invention, a tubular cap body is inserted into the tube end region of the coated steel pipe and the position is fixed; and a ring-shaped cap head providing a protective contact surface by covering the exposed end surface of the tube end region at the rear end of the cap body, wherein the cap body includes at least one or more protruding from the outer periphery and embedded in the inner periphery of the tube end region. There may be provided a protective cap having a spike, the position of which is fixed by the spike when inserted into the region of the tube end.

According to an embodiment of the present invention, a through opening is formed in the center, and a ring-shaped receiving groove is formed around the through opening to accommodate the tube end region of the coated steel pipe to protect the exposed end surface of the tube end region, When the tube end region is accommodated in the receiving groove, the receiving groove is configured to be expandable and deformable within an elastic range by the thickness of the tube end region, so that the tube end region is accommodated in the receiving groove in close contact. can be provided.

The end protective cap according to the embodiment of the present invention as described above, the central inner ring (inner ring) for providing the through opening; an outer ring around the inner ring; and a connection ring configured to form a receiving groove between the inner ring and the outer ring by shielding a rear end portion between the inner ring and the outer ring, wherein at least one of the inner ring and the outer ring is made of an elastic material and formed in a shape inclined toward the receiving groove, when the tube end region is accommodated in the receiving groove, the receiving groove is expanded within an elastic range by the thickness of the tube end region to accommodate the tube end region in a close contact can do.

Meanwhile, at least one or more spikes embedded in the inner periphery of the tube end region may protrude from a portion of the receiving groove opposite to the inner periphery of the tube end region.

According to an embodiment of the present invention, at least one end of a first coated steel pipe having a socket (socket); a second coated steel pipe having an insertion tube provided at at least one end of the tube providing a tube end region having an exposed end surface, the tube inserted into the socket; a sealing member interposed between the socket and the cannula; a fastening device for pressing the sealing member between the socket and the insertion tube and preventing separation of the socket and the insertion tube; A sheathed steel pipe connecting structure may be provided, including a protective cap provided on the end area of the tube end. In this case, the tube end protection cap may include the cap body and the cap head, and may have the central through-opening and the elastically deformable accommodating groove around it.

Here, the socket includes: a socket body formed by pipe expansion at at least one end of the first coated steel pipe and having a socket end in a shape that is open to the outside at the tip; and a socket ring disposed on the outer periphery of the socket end, and at least one spike embedded in the outer periphery of the socket end may be formed on the inner periphery of the socket ring.

Further, the socket ring, the spike is formed on the inner periphery, the outer periphery of the rear end is formed with a coupling protrusion along the outer periphery of the inner ring; The inner ring may include an outer ring disposed on the engaging jaw of the inner ring, the outer ring having an inner circumference larger than the maximum outer circumference of the socket end, and the inner ring may be divided into a plurality of units.

According to an embodiment of the present invention, at least one end of a first coated steel pipe provided with a socket; a second coated steel pipe having an insertion tube provided at at least one end of the tube providing a tube end region having an exposed end surface, the tube inserted into the socket; a sealing member interposed between the socket and the insertion tube; a fastening device for pressing the sealing member between the socket and the insertion tube and preventing separation of the socket and the insertion tube; A tube end protection cap comprising a tubular cap body inserted into the tube end region and a ring-shaped cap head providing a contact surface that covers and protects the exposed end surface of the tube end region at the rear end of the cap body, wherein the cap The body protrudes from the outer periphery and is formed in a closed ring shape, has at least one or more spikes embedded in the inner periphery of the tube end region, and a sealing material is applied between the cap head and the tube end region, a coated steel pipe connection structure may be provided. .

Means of solving the problem will be more specific and clear through the examples, drawings, etc. described below. In addition, various solutions other than the solutions mentioned below may be additionally suggested.

According to an embodiment of the present invention, by safely protecting the tube end region of the coated steel pipe whose end surface is exposed without the coating of the coating material or coated with the coating material from the outside, the end surface coating of the tube end region is maintained in an intact state for a long time or exposed. Corrosion of the finished end surface can be prevented. Also, even if the end surface of the pipe end region is corroded, the rate at which the corroded part spreads can be delayed, and the fluid flowing along the pipe can be prevented from being contaminated by the corroded part.

In addition, since the pipe end of the coated steel pipe is covered by the pipe end protection cap, it is possible to actively prevent damage due to the inner coating or the outer coating being stamped on the pipe end when the coated steel pipes are connected to each other in an insertion manner.

In an embodiment of the present invention, the first coated steel pipe and the second coated steel pipe connected to each other may be moved in a direction in which they are separated by various external forces. However, according to the embodiment of the present invention, the more the force is applied to the first and second coated steel pipes in the separation direction, the deeper the spike of the socket ring is embedded in the outer circumferential surface of the socket end. Accordingly, the separation of the first or second coated steel pipe can be more reliably prevented by the clamping force of the fastening device and the pressing action of the spike of the socket ring.

Effects of the present invention are not limited thereto, and other effects not mentioned will be clearly understood by those skilled in the art from this specification and the accompanying drawings.

1 is a cross-sectional view showing a clad steel pipe connection structure according to a first embodiment of the present invention.
FIG. 2 is an enlarged view showing part A of FIG. 1 .
3 is a cross-sectional perspective view illustrating an assembled state of the socket ring shown in FIG. 1 .
4 is a perspective view illustrating an exploded state of the socket ring shown in FIG. 1 .
Figure 5 is a perspective view showing the end protective cap shown in Figure 1;
6 is a cross-sectional perspective view showing the end protection cap shown in FIG. 1 .
7 is a cross-sectional view illustrating a process of applying the end protection cap shown in FIG. 1 .
8 is a cross-sectional view illustrating a pipe end protection cap, which is an essential part of a clad steel pipe connection structure according to a second embodiment of the present invention, and an application process thereof.
9 is a perspective view illustrating a pipe end protection cap, which is an essential part of a clad steel pipe connection structure according to a third embodiment of the present invention.
10 is a cross-sectional perspective view illustrating the end protective cap shown in FIG. 9 .
11 is a cross-sectional view showing the application process of the end protective cap shown in FIG.

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art can easily implement them. However, the present invention may be embodied in various other forms and is not limited to the embodiments described herein.

In describing an embodiment of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the specific description is omitted, and parts with similar functions and actions are The same reference numerals are used throughout the drawings.

At least some of the terms used in the specification are defined in consideration of functions in the present invention, and thus may vary according to user, operator intention, custom, and the like. Therefore, the terms should be interpreted based on the content throughout the specification. In addition, in the specification, when a certain component is included, this means that other components may be further included, rather than excluding other components, unless otherwise stated. And, when it is said that a certain part is connected (or coupled) with another part, it is not only directly connected (or coupled), but also indirectly connected (or coupled) with another part therebetween. include

On the other hand, in the drawings, the size or shape of the component, the thickness of the line, etc. may be expressed somewhat exaggerated for the convenience of understanding.

A clad steel pipe connection structure according to a first embodiment of the present invention is shown in FIGS. 1 to 7 .

Referring to FIG. 1 , reference numerals 10 and 20 denote a first coated steel pipe on one side and a second coated steel pipe on the other side to be connected to each other. ) and the second coated steel pipe 20 are configured to be connected to each other by a mechanical joint method. In addition, for this purpose, the clad steel pipe connection structure according to the first embodiment of the present invention includes a socket ring 30 constituting a part of a socket for interconnection of clad steel pipes, and a sealing for maintaining airtightness when interconnecting the clad steel pipes. a member (40), and a fastening device (50) for maintaining the interconnection of the clad steel pipe.

Each of the first coated steel pipe 10 and the second coated steel pipe 20 includes a steel pipe and a coating layer, and the coating layer includes an inner surface coating and an outer surface coating provided on the inner and outer peripheral surfaces of the steel pipe, respectively. For example, the inner surface coating and the outer surface coating may be made of a coating material including polyethylene (PE) to have certain elasticity. The first coated steel pipe 10 and the second coated steel pipe 20 may be a straight straight pipe or a deformed pipe such as a curved pipe or a T-pipe.

1 and 2, at least one end of the first coated steel pipe 10 has an outer diameter of the inserted tube so that the inserted tube, which is either end of the second coated steel pipe 20, can be inserted. A socket body 11 having a relatively large inner diameter is provided, and a distal end of the socket body 11 is provided with a socket end 12 extending from the distal end of the socket body 11 . The socket body 11 and the socket end 12 constitute a socket body, and the socket body together with the socket ring 30 constitutes a socket. The socket body is formed by pipe expansion processing.

The insertion tube of the second coated steel tube 20 is inserted into the socket body 11 . The socket end 12 is provided in a shape that gradually opens outward toward the end, so that the inner and outer circumferential surfaces have inclined surfaces of a certain angle, respectively, and a ring as an empty space between the insertion tube and the insertion tube inserted into the socket body 11 A sealing space of the shape is formed.

2 to 4, the socket ring 30 is disposed in a state fitted to the outer periphery of the socket end 12, and includes at least one or more spikes (first spikes, 33). The sealing member 40 is made of an airtight material such as rubber, and is inserted into the sealing space between the socket end 12 and the insertion tube. The fastening device 50 includes a first coated steel pipe 10 having a socket ring 30 disposed on the outer periphery of the socket end 12 and a second coated steel pipe having an insertion tube inserted into a socket body (refer to reference numerals 11 and 12). By fastening 20 to each other, the first coated steel pipe 10 and the second coated steel pipe 20 connected to each other are prevented from being separated.

The spike 33 is formed on the inner circumferential surface of the socket ring 30 and constitutes the outer circumferential surface of the socket end 12 when a force is applied to the first coated steel pipe 10 and the second coated steel pipe 20 in a separation direction. It is embedded in the outer coating to prevent the separation of the first coated steel pipe 10 and the second coated steel pipe 20 together with the fastening device (50).

The spike 33 of the socket ring 30 may be formed so that the portion including the tip is pointed to be easily embedded in the outer circumferential surface of the socket end 12, and the protrusion length and width are constant. And, the spike 33 may be formed to have a closed ring shape.

A recess 13 having a shape corresponding to the shape of the spike 33 may be formed on the outer circumferential surface of the socket end 12 as the spike 33 is driven. That is, the concave recess 13 may be formed in a closed ring shape along the outer circumferential direction of the socket end 12 .

3 and 4 , the socket ring 30 includes an inner ring 31 and an outer ring 35 . The inner ring 31 has a spike 33 formed on the inner periphery, and a coupling jaw 34 having a recessed shape along the outer periphery on the outer periphery of the rear end is formed. The inner ring 31 has an inclined surface whose inner peripheral surface corresponds to the inclined surface on the outer peripheral side of the socket end 12 . is formed to The inner ring 31 has a structure divided into a plurality of unit bodies 31A and 31B arranged along the circumferential direction. The outer ring 35 is disposed on the engaging jaw 34 of the inner ring 31 , and is formed to have a larger inner circumference than the maximum outer circumference of the socket end 12 .

Such a socket ring 30 is first arranged on the outer periphery of the socket end 12 in such a way that the outer ring 35 is sandwiched from the socket end 12 side, and then a plurality of unit bodies 31A constituting the inner ring 31, 31B) is placed on the outer periphery of the socket end 12, and then the outer ring 35 is placed on the engaging jaw 34 of the inner ring 31, so that it can be simply and quickly placed on the outer periphery of the socket end 12. .

As shown in FIGS. 1 and 2 , the fastening device 50 is a pipe fastening mechanism for fastening the pressure wheel 51 , the socket ring 30 and the pressure wheel 51 fitted to the outer periphery of the second coated steel pipe 20 . (52, 53), and a position fixing mechanism 54 for fixing the position of the pressure wheel 51 with respect to the second coated steel pipe 20.

Here, the tube fastening mechanisms 52 and 53 are configured to bring the socket ring 30 and the pressure wheel 51 closer to each other by fastening the bolts. The pressure wheel 51 has a pressing surface that presses the sealing member 40 with respect to the sealing space when the bolts are tightened by the tube fastening mechanisms 52 and 53 . According to the pressing action by the pressing surface of the pressing wheel 51 , the sealing member 40 is accommodated in the sealing space in a press-fit state.

The tube fastening mechanisms 52 and 53 are composed of a plurality of pairs of fastening bolts 52 and fastening nuts 53 that are screwed to each other. As for the fastening bolts 52 , the bolt heads are respectively caught on the locking jaws 36 formed on the outer ring of the socket ring 30 . The pressure wheel 51 has through holes through which the bolt bodies of the fastening bolts 52 pass, respectively. The through holes may be spaced apart from each other in a circumferential direction based on the center of the pressure wheel 51 . The fastening nuts 53 are respectively coupled to the bolt bodies of the fastening bolts 52 passing through the through holes of the pressure wheel 51 in a state of being caught by the locking jaws 36 . The fastening bolts 52 may be hook bolts.

The positioning mechanism 54 is composed of a plurality of spike bolts. The spike bolts 54 are screwed to each other in a radial direction on the pressure wheel 51 and are spaced apart or approached with respect to the outer circumferential surface of the second coated steel pipe 20 according to the direction of rotation. Of course, when the spike bolts 54 approach the outer peripheral surface of the pressing wheel 51, the position of the pressing wheel 51 is fixed. The spike bolts 54 may be respectively disposed between the through holes of the pressure wheel 51 .

The coated steel pipe connection structure according to the first embodiment of the present invention is exposed as it is without coating of a coating material in the inserted tube of the second coated steel tube 20 or is coupled to a tube end region having an end surface coated with a coating material, thereby forming the inserted tube. It further includes a pipe end protective cap 60 of synthetic resin for protecting the tube end area from the outside.

As shown in FIGS. 5 to 7 , the tube end protection cap 60 is inserted into the tube end region of the insertion tube and has a fixed position in the tubular cap body 61 , and at the rear end of the cap body 61 . and a cap head 65 in the shape of a ring plate that covers and protects the end face of the tube end region. Since the cap head 65 has a contact surface, it is possible to limit the insertion depth of the cap body 61 with respect to the tubular end region of the cannula. The cap head 65 extends outwardly from the rear end portion of the cap body 61 .

The cap body 61 is made of synthetic resin. The cap body 61 is formed so that the distal end portion 63 has a larger outer circumference than the inner circumference of the tube end region. The distal end portion 63 of the cap body 61 is formed with a cutout portion 64 that induces a reduction deformation of the distal end portion 63 within an elastic range. Accordingly, when the cap body 61 is inserted into the tube end region, the outer periphery of the distal end portion 63 is reduced, and the distal end portion 63 is in close contact with the inner periphery of the tube end region by its own elastic force to fix the position (Fig. 7).

At least one or more spikes (second spikes, 62 ) are formed between the front end portion 63 and the rear end portion of the cap body 61 . The spikes 62 of the cap body 61 protrude from the outer periphery of the cap body 61 and are embedded in the inner periphery of the tube end region. The spike 62 of the cap body 61 is formed with a sharp tip so as to be easily embedded in the inner surface coating constituting the inner circumferential surface of the tube end region. The spike 62 of the cap body 61 is formed to have a closed ring shape. A groove into which the spike 62 of the cap body 61 is inserted may be formed in advance on the inner circumferential surface of the tube end region. The groove of the tube end region may be formed in a shape corresponding to the spike 62 of the cap body 61 on the inner surface coating of the tube end region.

The cap head 65 may be formed to have a flange structure. The cap head 65 may be integral with the cap body 61 .

Although not shown, a sealing material may be applied between the cap head 65 and the tube end region. According to this sealing material and the closed ring-shaped spike 62 of the cap body 61, water as a fluid flowing along the pipe line is prevented from flowing between the pipe end protection cap 60 and the pipe end area, so that the exposed The end surface can be protected more safely.

The main part of the clad steel pipe connection structure according to the second embodiment of the present invention is shown in FIG. 8 . Referring to FIG. 8 , in the clad steel pipe connection structure according to the second embodiment of the present invention, compared with the first embodiment of the present invention, other configurations and actions are all the same, the pipe end protection cap 60 The only difference is that the outer cover 68 is further included.

The outer cover 68 provides a contact surface that covers and protects the outer peripheral surface of the tube end region at the edge of the cap head 65 . The outer cover 68 is formed in a ring shape, and the contact surface of the outer cover 68 is formed as an inner circumferential surface of the outer cover 68 . The outer cover 68 extends forward from the edge portion of the cap head 65, and includes the socket body (refer to reference numeral 11 in FIG. 1) and the second covering of the first coated steel pipe (refer to 10 in FIG. 1) and the second covering. It is press-fitted between insertion tubes of a steel pipe (refer to reference numeral 20 in FIG. 1) and is formed to have a thickness in close contact with the tube end region. The outer cover 68 may be integral with the cap head 65 .

The main parts of the clad steel pipe connection structure according to the third embodiment of the present invention are shown in Figs. As shown, the clad steel pipe connection structure according to the third embodiment of the present invention has the same configuration and operation as compared to the first or second embodiment of the present invention. Only the configuration of the protective cap 70 is different. Looking at this:

In the clad steel pipe connection structure according to the third embodiment of the present invention, the pipe end protection cap 70 has a through opening 70A formed in the center, and accommodates the tube end region of the inserted tube around the through opening 70A. A ring-shaped accommodating groove 70B is formed to protect the exposed end surface of the tube end region. That is, it is comprised so that it may have the central through-opening 70A and the periphery accommodation groove|channel 70B. At this time, the receiving groove 70B is configured to be expandable and deformable within an elastic range by the thickness of the tube end region when the tube end region is accommodated. Accordingly, the receiving groove 70B accommodates the tube end region in close contact (see FIG. 11 ) to prevent water from flowing into the space between the receiving groove 70B and the tube end region as a fluid flowing along the conduit.

Specifically, such a tube end protection cap 70 includes an inner ring 71 at the center providing a through opening 70A, an outer ring 73 disposed around the inner ring 71, and an inner ring 71 ) and a connecting ring 75 for shielding the rear end portion between the outer ring 73 . In this case, the connecting ring 75 connects the inner ring 71 and the outer ring 73 , and a receiving groove 70B is formed between the inner ring 71 and the outer ring 73 . The inner ring 71 , the outer ring 73 , and the connecting ring 75 are all made of an elastic material such as rubber, silicone, or soft synthetic resin. The inner ring 71 , the outer ring 73 , and the connecting ring 75 may be integrally formed.

The inner ring 71 and the outer ring 73 are formed in a shape inclined at a certain angle toward the receiving groove 70B, so that when the tube end region is accommodated in the receiving groove 70B, the receiving groove 70B has a thickness of the tube end region. It can be expanded within the elastic range and accommodated in close contact with the tube end area.

The inner ring 71 has an outer circumferential surface 72 that is in close contact with the inner circumferential surface of the tube end region. The outer ring 73 has an inner circumferential surface 74 that is in close contact with the outer circumferential surface of the tube end region. The outer ring 73 disposed between the socket and the inserted tube can prevent damage to the inner surface coating of the socket and the outer surface coating of the inserted tube in the process of connecting the first coated steel pipe and the second coated steel tube.

For reference, in FIG. 11 , a state before and a state in which the end protective cap 70 is coupled to the end region can be confirmed, respectively. The end protection cap 70 is coupled to the end region and when the end region is accommodated in the receiving groove 70B, the receiving groove 70B expands by the thickness of the end region by elastic deformation and is in close contact with the end region. Of course, when the tube end protection cap 70 is separated from the tube end region, the receiving groove 70B is restored to its original state.

Meanwhile, the inner ring 71 has at least one or more spikes (second spikes, 72S). The spike 72S of the inner ring 71 protrudes from the outer peripheral surface 72 of the inner ring 71 and is embedded in the inner periphery of the tube end region. The spike 72S of the inner ring 71 is formed with a sharp tip so as to be easily embedded in the inner surface coating constituting the inner circumferential surface of the tube end region. The spike 72S of the inner ring 71 is formed to have a closed ring shape. In the inner peripheral surface of the tube end region, a groove into which the spike 72S of the inner ring 71 is inserted may be formed in advance. The groove of the tube end region may be formed in a shape corresponding to the spike 72S of the inner ring 71 on the inner surface coating of the tube end region.

Although the present invention has been described above, the present invention is not limited by the disclosed embodiments and the accompanying drawings, and various modifications may be made by those skilled in the art without departing from the technical spirit of the present invention. In addition, the technical ideas described in the embodiments of the present invention may be implemented independently, or two or more may be implemented in combination with each other.

10: first coated steel pipe
11: socket body
12: socket end
20: second coated steel pipe
30: socket ring
40: sealing member
50: fastening device
60, 70: tube end protection cap

Claims (12)

a first coated steel pipe provided with a socket at at least one end thereof; a second coated steel pipe having an insertion tube inserted into the socket at at least one end thereof; a sealing member interposed between the insertion tube inserted into the socket and the socket; a fastening device for pressing the sealing member between the socket and the insertion tube and preventing the socket and the insertion tube from being separated; Comprising a tube end protection cap provided on the tube end region of the cannula,
The socket includes: a socket body provided at at least one end of the first coated steel pipe by pipe expansion and formed with a socket end having an inclined shape that is spread outward at the tip; a socket ring disposed on the outer periphery of the socket end and having at least one first spike formed on an inner periphery having an inclination corresponding to the socket end and embedded in the outer periphery of the socket end at which the first spike is inclined,
The sealing member is inserted into the sealing space between the inclined socket end and the insertion tube,
The fastening device includes: a pressure wheel mounted on the outer periphery of the second coated steel pipe and having a pressing surface for pressing the sealing member into the sealing space; and a pipe fastening mechanism for approaching the socket ring and the pressure wheel by bolting in a state in which the socket ring and the pressure wheel are caught,
The tube end protection cap may include: a tubular cap body inserted into the tube end region of the insertion tube and having a fixed position; and a ring-shaped cap head providing a rear end portion of the cap body with a contact surface that covers and protects the end surface of the tube end region,
The cap body is formed so that the tip portion has a larger outer periphery than the inner periphery of the tube end region, and a cutout portion for inducing a reduction deformation of the tip portion within an elastic range is formed on the tip portion to the tube end region When inserted, the outer periphery of the distal end is in close contact with the inner periphery of the tube end region and the position is fixed,
The cap body has at least one second spike protruding from an outer periphery between the front end portion and the rear end portion and embedded in the inner periphery of the tube end region,
The plurality of second spikes are formed in a closed ring shape and are spaced apart from each other, and the inner periphery of the tube end region is characterized in that a groove into which the plurality of second spikes are embedded is formed,
clad steel pipe connection structure. delete delete delete delete delete delete delete delete delete The method according to claim 1,
The socket ring is
an inner ring in which the first spike is formed on an inner periphery and a coupling jaw is formed on the outer periphery of the rear end in the outer periphery direction; and an outer ring disposed on the engaging jaw of the inner ring and having an inner circumference larger than the maximum outer circumference of the socket end and on which the tube fastening mechanism is caught,
characterized in that the inner ring is divided into a plurality of units,
clad steel pipe connection structure. delete

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