Pipe fitting and steel pipe connection method

Abstract

To provide a pipe joint which enables easy connection of a steel pipe with the pipe joint while keeping a movement prevention force acting in a removal direction when the steel pipe and the pipe joint are connected.SOLUTION: A pipe joint 12 connecting a steel pipe K in which a recessed section is formed at a connection tip side outer periphery, includes: an inner member 20 into which the steel pipe K is inserted from the side of one end part 20A; an inner seal member which seals a space between an outer periphery of the steel pipe K and an inner periphery of the inner member 20; claw members 24A, 25A which are disposed at the inner periphery of the inner member and engage with the recessed section to restrict movement of the steel pipe in a direction opposite to an insertion direction of the steel pipe; a position check part which is formed at the inner member 20 and enables a user to view a state that a tip of the steel pipe K is inserted into a proper position of the inner member 20, from the outside of the inner member 20; an outer member 40 into which the inner member 20 is inserted from the side of the one end part 40A and which holds the inner member 20 within a cylinder; and an outer seal member which seals a space between an inner periphery of the outer member 40 and an outer periphery of the inner member 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology disclosed in this application relates to a pipe joint and a method for connecting steel pipes. [Background technology]

[0002] Conventionally, steel pipes have been widely used for piping within floors and walls of buildings. When these steel pipes are connected to other steel pipes, flanges or screw connections are used. For example, Patent Document 1 discloses a pipe joint structure in which a steel pipe flange is used to connect to a mating member with a bolt. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-55742 [Patent Document 2] Patent No. 5219266 Summary of the Invention [Problem to be solved by the invention]

[0004] When a flange is fastened with screws, as in Patent Document 1, the degree of tightening and other factors largely depend on the skill of the installer, and problems may occur. On the other hand, as in Patent Document 2, it is possible to hold a steel pipe in a pipe fitting by inserting it to a specified position, as in a pipe fitting for flexible pipes, but in order to apply this to steel pipes, some ingenuity is required to maintain the force preventing movement in the removal direction.

[0005] In consideration of the above, the present invention aims to provide a pipe fitting structure and a method for connecting steel pipes that can easily connect steel pipes to a pipe fitting while maintaining a force preventing movement in the removal direction. [Means for solving the problem]

[0006] A first aspect of the pipe fitting of the present invention is a pipe fitting for connecting a steel pipe having a groove formed on its outer periphery in the connection tip direction, and comprises: a cylindrical inner member into which the steel pipe is inserted from one end in the axial direction of the cylinder; an inner seal member which is annular and arranged on the inner periphery of the inner member, sealing between the outer periphery of the steel pipe and the inner periphery of the inner member; claw members which are annular and arranged on the inner periphery of the inner member, engaging with the groove to restrict movement of the steel pipe in the direction opposite to the insertion direction; a position confirmation portion formed on the inner member, which makes it possible to visually confirm from the outside of the inner member that the tip of the steel pipe has been inserted into the correct position of the inner member where the claw members engage with the groove; a cylindrical outer member into which the inner member is inserted, holding the inner member within the cylinder; and an outer seal member which is arranged between the inner periphery of the outer member and the outer periphery of the inner member, sealing between the inner periphery of the outer member and the outer periphery of the inner member.

[0007] The pipe joint of the first aspect has an inner member and an outer member. The inner member is cylindrical, and a steel pipe is inserted into it from one end in the axial direction of the cylinder. An inner seal member and a claw member are arranged on the inner periphery of the inner member. The inner seal member seals the gap between the steel pipe and the inner member, and the claw member prevents the steel pipe from coming loose. The claw member engages with the recessed groove, so that it can maintain a force preventing movement in the removal direction.

[0008] The inner member is inserted into the outer member from one end in the axial direction of the cylinder, and the inner member is held within the cylinder. The gap between the inner periphery of the outer member and the outer periphery of the inner member is sealed by an outer seal member.

[0009] The inner member is provided with a position confirmation part that enables a worker to visually confirm from the outside of the inner member whether the tip of the steel pipe is inserted into the proper position of the inner member where the claw member and the recessed groove engage. Therefore, the worker can easily visually confirm whether the steel pipe is inserted into the proper position of the inner member.

[0010] In a pipe fitting according to a second aspect of the present invention, the position confirmation portion is provided on the insertion inner side of the outer seal member.

[0011] According to the pipe joint of the second aspect, since the position confirmation portion is not provided on the insertion front side of the outer seal member, sealing between the outer member and the inner member can be easily performed.

[0012] In a third aspect of the pipe fitting of the present invention, the position confirmation portion has an abutment portion formed in a tube opening at the other end of the inner member, against which the tip of the steel pipe abuts when the steel pipe is positioned in the appropriate position.

[0013] According to the pipe joint of the third aspect, the steel pipe can be inserted into the appropriate position in the inner member by abutting the tip of the steel pipe against the abutment portion formed on the tube opening at the other end of the inner member.

[0014] A fourth aspect of the method for connecting a steel pipe of the present invention is a method for connecting a steel pipe to a pipe fitting described in any one of claims 1 to 3, in which a recess is formed on the outer periphery of the steel pipe at the connection tip end, the steel pipe is inserted into the appropriate position from one end side of the inner member, the inner member is inserted into the outer member, and the inner member is held in the outer member.

[0015] In the fourth embodiment of the steel pipe connecting method, first, a recess is formed on the outer periphery of the steel pipe at the connection tip end. Next, the steel pipe is inserted into the appropriate position from one end of the inner member. Insertion into the appropriate position can be visually confirmed from the outside of the inner member via the position confirmation section. Thereafter, the inner member is inserted into the outer member and held by the outer member. This makes it easy to confirm that the steel pipe has been inserted into the appropriate position before connecting. [Effects of the Invention]

[0016] Since the present invention has the above-described configuration, when connecting a steel pipe to a pipe joint, the connection can be easily made while maintaining a force preventing movement in the removal direction. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a half cross-sectional view of a pipe joint structure according to an embodiment of the present invention. [Figure 2] 1 is a perspective view of a pipe joint structure 10 of the present embodiment before connection. [Figure 3] FIG. 2 is a half cross-sectional view of the inner member of the present embodiment. [Figure 4] FIG. 2 is a half cross-sectional view of an outer member of the present embodiment. [Figure 5] FIG. 10 is a perspective view of an inner member according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] A pipe joint and a method for connecting steel pipes according to an embodiment of the present invention will be described with reference to the drawings.

[0019] Fig. 1 shows a half cross-sectional view of a pipe joint structure 10 in which a steel pipe K is connected to a pipe joint 12 of this embodiment. The pipe joint structure 10 has a structure in which a steel pipe K is inserted into the pipe joint 12. The pipe joint 12 is a joint that connects the steel pipe K to other piping or the like. Fig. 2 shows a perspective view of the pipe joint structure 10 before connection.

[0020] The steel pipe K is made of metal, and has a first recessed groove K1 and a second recessed groove K2 formed on its outer periphery on the connection tip side. The first recessed groove K1 is formed so that the connection tip side of the groove width (the tip side of the steel pipe K) is located at a position a distance D1 before the tip of the steel pipe K, and is a groove that surrounds the outer periphery of the steel pipe K. The second recessed groove K2 is formed so that the connection tip side of the groove width is located at a position a distance D2 before the tip of the steel pipe K that is farther from the tip of the steel pipe K than the first recessed groove K1, and is a groove that surrounds the outer periphery of the steel pipe K. The groove widths of the first recessed groove K1 and the second recessed groove K2 correspond to the claw members 24A and 25A described below, and in this embodiment, are approximately the same as the groove widths of the first claw groove 24 and the second claw groove 25 described below.

[0021] The pipe joint 12 has an inner member 20 and an outer member 40 that are arranged coaxially. Hereinafter, the central axes of the inner member 20 and the outer member 40 are referred to as S. The inner member 20 is cylindrical and made of metal, and has an annular flange portion 22 formed on the outer periphery of one end portion 20A. The flange portion 22 has a plurality of bolt holes 22A (four in this embodiment) that penetrate in the direction of the central axis S. The outer circumferential surface of the inner member 20 is smooth and has the same outer diameter with no steps except for the flange portion 22.

[0022] A first seal groove 23, a first claw groove 24, a second claw groove 25, and a second seal groove 26 are formed in the inner peripheral surface of the other end 20B side of the inner member 20 in this order from the other end 20B side. An O-ring 23A is disposed in the first seal groove 23, and an O-ring 26A is disposed in the second seal groove 26.

[0023] A claw member 24A is disposed in the first claw groove 24, and a claw member 25A is disposed in the second claw groove 25. Claw members 24A, 25A are annular and have a V-shaped cross section. Claw members 24A, 25A are disposed so that the opening of the V faces the other end 20B, and one side of the V-shape disposed on the radially outer side is disposed along the bottom of first claw groove 24 and the bottom of second claw groove 25, respectively, and the other side of the V-shape disposed on the radially inner side protrudes radially inward from first claw groove 24 and second claw groove 25, respectively. Claw members 24A, 25A are made of metal and are elastically deformable so that the opening of the V-shape closes.

[0024] An abutment portion 21 is formed at the tip of the other end portion 20B of the inner member 20. The abutment portion 21 protrudes radially inward from the tip of the other end portion 20B of the inner member 20 to a position substantially flush with the inner wall of the steel pipe K. The first claw groove 24 is formed at a position distance D1 from the thickness inner wall of the abutment portion 21, and the second claw groove 25 is formed at a position distance D2 from the thickness inner wall of the abutment portion 21. As a result, when the steel pipe K is inserted into the inner member 20 and the tip is abutting against the abutment portion 21, the first recessed line K1 and the first claw groove 24 are positioned opposite each other in the radial direction, and the second recessed line K2 and the second claw groove 25 are positioned opposite each other in the radial direction.

[0025] The outer member 40 is made of metal and has a cylindrical shape, with an annular flange portion 41 formed on the outer periphery of one end portion 40A and an annular flange portion 42 formed on the outer periphery of the other end portion 40B. A plurality of bolt holes 41A, 42A (four in this embodiment) are formed in the flange portions 41, 42, penetrating in the direction of the central axis S. The flange portion 22 of the inner member 20, inserted from the one end portion 40A side of the outer member 40, and the flange portion 41 of the outer member 40 are overlapped, and a bolt B is inserted into the bolt holes 22A, 41A and screwed into a nut N to fasten the flange portions 22, 41 together.

[0026] A first seal groove 43, a second seal groove 44, a third seal groove 45, and a fourth seal groove 46 are formed on the inner peripheral surface of the outer member 40, in that order from one end 40A side. An O-ring 43A is disposed in the first seal groove 43, an O-ring 44A is disposed in the second seal groove 44, an O-ring 45A is disposed in the third seal groove 45, and an O-ring 46A is disposed in the fourth seal groove 46.

[0027] The length of the outer member 40 in the direction of the central axis S is approximately twice the length of the inner member 20 in the same direction. Another pipe or the like is connected to the other end 40B of the outer member 40. In this embodiment, it is a socket-type pipe joint.

[0028] Next, the operation of this embodiment will be described.

[0029] When connecting a steel pipe K to a pipe fitting 12, first, a first groove K1 and a second groove K2 are formed on the outer periphery of the connection tip side of the steel pipe K. The first groove K1 is formed at a position distance D1 from the connection tip, and the second groove K2 is formed at a position distance D2 from the connection tip.

[0030] Next, the steel pipe K, on ​​which the first grooves K1 and the second grooves K2 are formed, is inserted into the inner member 20 from the one end 20A side. When the steel pipe K passes over the claw members 25A and 24A, the claw members 25A and 24A are pushed by the tip of the steel pipe K, causing the claw members 25A and 24A to elastically deform so as to narrow the V-shaped opening. Then, the tip of the steel pipe K is brought into contact with the contact portion 21.

[0031] In this state, the outer peripheral surface of the steel pipe K and the inner peripheral surface of the inner member 20 are sealed by the O-ring 23A in the first seal groove 23 and the O-ring 26A in the second seal groove 26. In addition, the claw member 24A returns to its original position so that its V-shaped opening opens and engages with the first recessed groove K1, and the claw member 25A also returns to its original position so that its V-shaped opening opens and engages with the second recessed groove K2. This restricts the movement of the steel pipe K in the direction of coming out of the inner member 20.

[0032] From the opening 21A, the worker can confirm that the connecting end of the steel pipe K is in contact with the contact portion 21, i.e., that the end of the steel pipe K is positioned in the appropriate position in the inner member 20. In the case of a pipe fitting in which the inner member 20 and the outer member 40 are not separate bodies, a connection portion for connecting another member is provided at the other end 20B of the inner member 20, making it difficult to visually confirm the position of the end of the steel pipe K.

[0033] With the steel pipe K inserted into the appropriate position of the inner member 20, the inner member 20 is inserted into the outer member 40 from one end 40A side. Then, the flange portion 22 is overlapped with the flange portion 41, and the bolt B is inserted into the bolt holes 22A, 41A and screwed into the nut N to fasten the flange portions 22, 41 together.

[0034] By connecting the steel pipe K to the pipe joint 12 in this manner, the steel pipe K can be easily and appropriately connected to the pipe joint 12.

[0035] In addition, by engaging the claw member 24A with the first recess K1 and the claw member 25A with the second recess K2, the movement of the steel pipe K in the direction of coming out of the inner member 20 is restricted, thereby maintaining a force preventing the steel pipe K from moving in the direction of coming out.

[0036] Furthermore, the inner member 20 and the outer member 40 can be easily joined by overlapping the flange portion 22 and the flange portion 41 and fastening them with bolts. In the pipe fitting 12 of this embodiment, no sealing portion is provided between the flange portion 22 and the flange portion 41, so problems such as one-sided tightening when fastening the bolt B are less likely to occur.

[0037] In addition, in this embodiment, a socket-type outer member 40 has been described as an example, but since the inner member 20 and the outer member 40 are separate bodies, the pipe joint can be made into a different shape by using an outer member 40 with a different shape on the other end 40B side. For example, by changing only the outer member 40, a pipe joint such as an elbow or a tee can be made.

[0038] In this embodiment, the abutting portion 21 is provided at the other end 20B of the inner member 20, but the abutting portion 21 is not necessarily required. By providing the abutting portion 21, the tip of the steel pipe K can be abutted against the abutting portion 21, thereby easily positioning the steel pipe K in the appropriate position of the inner member 20.

[0039] Furthermore, in this embodiment, the contact portion 21 is annular, but as shown in Fig. 5, the contact portion 21B may be provided at a portion (two portions in Fig. 5) in the circumferential direction of the other end portion 20B of the inner member 20. In this case, it is possible to confirm from the opening 21C whether the steel pipe K is placed in the appropriate position of the inner member 20.

[0040] In addition, in this embodiment, the inner member 20 and the outer member 40 are joined by bolting the flange portion 22 and the flange portion 41 together, but the inner member 20 may also be held to the outer member 40 by other holding means such as a clip.

[0041] In addition, in this embodiment, the first seal groove 43, the second seal groove 44, the third seal groove 45, and the fourth seal groove 46 are formed on the inner surface of the outer member 40, but instead of these, a groove for placing an O-ring may be formed on the outer surface of the inner member 20. [Explanation of symbols]

[0042] 12 Pipe fittings 20 Inner member 20A One end 20B Other end 21, 21B Contact part 21A opening (position confirmation part) 21C opening (position confirmation part) 23A, 26A O-ring (inner seal material) 24A, 25A claw member 40 Outer member 40A One end 40B Other end 43A, 44A O-ring (outer seal material) K steel pipe K1 1st concave line (concave line) K2 2nd concave line (concave line)

Claims

1. A pipe joint for connecting a steel pipe having a groove formed on the outer periphery of the connection tip side, an inner member having a cylindrical shape and into which the steel pipe is inserted from one end side in the cylindrical axis direction; an inner seal member that is annular and disposed on the inner periphery of the inner member, and that seals between the outer periphery of the steel pipe and the inner periphery of the inner member; a claw member that is annular and disposed on the inner periphery of the inner member, and that engages with the groove to restrict movement of the steel pipe in a direction opposite to the insertion direction; an outer member that is separate from the inner member and has a cylindrical shape, the inner member is inserted into the cylindrical outer member, and the outer member holds the inner member in the cylindrical outer member; an outer seal member disposed between the inner periphery of the outer member and the outer periphery of the inner member, and sealing the gap between the inner periphery of the outer member and the outer periphery of the inner member; a position confirmation part formed in a tube opening at the other end of the inner member, the position confirmation part having an abutment part against which the tip of the steel pipe abuts when the tip of the steel pipe is inserted into a position where the claw member and the recessed strip are engaged as the proper position of the inner member, and making it possible to visually confirm from the outside of the inner member that the tip of the steel pipe abuts against the abutment part before the inner member is inserted into the outer member; A pipe fitting comprising:

2. The pipe joint according to claim 1 , wherein the position confirmation portion is provided on a rear side of the outer seal member in the insertion direction.

3. A method for connecting a steel pipe to the pipe joint according to claim 1 or 2, A recess is formed on the outer periphery of the steel pipe at the connection tip end side, Inserting the steel pipe into the appropriate position from one end side of the inner member, The inner member is inserted into the outer member and held by the outer member. How to connect steel pipes.

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