JP4449046B2 - Metal flexible pipe joint structure - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a joint structure of a metal flexible tube having a bellows portion formed into a wave shape for use by circulating a fluid in a pipe line.
[0002]
BACKGROUND OF THE INVENTION
Generally, piping installed in mechanical equipment that circulates fluid has a bent pipe part and a misalignment part due to the mounting structure. In order to guide the fluid through this bent pipe part or misalignment part, bendability is required. A metal flexible tube having a bellows portion having a corrugated shape is often used. High-temperature fluids or chemical fluids may be used for machinery and equipment. For this reason, metal flexible tubes are made of stainless steel, a material that has heat resistance and corrosion resistance, depending on the properties of the fluid used. Is often used. In this case, this metal flexible tube has a double-pipe structure in which two types of thin plate pipes of different materials are overlapped on the bellows part from the viewpoint of further improving flexibility and corrosion resistance and from the viewpoint of manufacturing cost. It has been known.
[0003]
[Problems to be solved by the invention]
When using a metal flexible tube in which two types of thin pipes with different materials are overlapped as in the conventional case, a metal using a material with excellent corrosion resistance on the inner layer side corresponding to the use conditions A flexible tube is used. As shown in FIGS. 3 and 4 , the end portions 42a and 42b of the inner layer tube 20 and the outer layer tube 22 of the metal flexible tube 12 that are doubly stacked are overlapped to have the same length, and the fitting 14 is attached. It is inserted and penetrated into the hole 16, and a double layer is formed on the seal surface 18 of the joint fitting 14 and folded back. In this case, since both the inner layer pipe 20 and the outer layer pipe 22 are in contact with a fluid using a chemical solution or the like, the inner layer pipe 20 and the outer layer pipe 22 are used for the surface of the outer layer pipe 22 formed of a material having inferior corrosion resistance or the like. There was a problem that the fluid touched and caused corrosion on the outer tube. Further, there is a gap in the overlapped portions of the overlapping end portions 42a and 42b of the inner layer tube 20 and the outer layer tube 22, and this gap is always in contact with the fluid to be used. A high-temperature fluid or a fluid using a chemical solution may also enter the gap, which may cause problems such as corrosion in the outer layer tube 22 formed of a material that is inferior in corrosion resistance to the material of the inner layer tube 20.
[0004]
The present invention has been made in view of the above-described conventional problems, and one object thereof is to form a seal surface portion of a metal flexible tube to be attached to a joint metal fitting at the time of joint connection with only an inner layer pipe having corrosion resistance, A flexible metal pipe that can be connected to other joint fittings in the joint bracket seal part with the working fluid in contact with the inner layer pipe only, and can significantly improve the corrosion resistance of the metallic flexible pipe in the joint part. The joint part structure of this invention and the connection method of the joint part of a metal flexible pipe are provided. Another object of the present invention is to provide a metal flexible tube that can reliably improve the corrosion resistance of the entire metal flexible tube by preventing the working fluid from completely contacting the overlap gap between the inner layer tube and the outer layer tube. It is to provide a joint structure.
[0005]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention is capable of forming a two- ply thin cylindrical pipe into a corrugated shape in which crests and troughs are repeated , and integrating a corrugated inner layer tube and a corrugated outer layer tube. In the joint structure of the flexible tube 12, the length of one end of the inner layer tube 20 is made longer than the length of one end of the corrugated outer layer tube 22 in the same overlapping portion so as to form the inner layer tube extension 26. The inner layer pipe extension 26 is inserted and penetrated into the mounting hole 16 of the fitting 14 so that the mounting hole 16 of the fitting 14 is fitted into the trough on the final end side of the metal flexible pipe , and the through end is inserted. The seal portion 19 is bent and stacked in a U-shape so that the pre-bending portion is in close contact with the side surface of the joint fitting 4, and one end portion of the corrugated outer layer tube 22 has a length in the axial direction of the mounting hole 16 of the joint fitting 14. Ended at an intermediate position, the internal fluid in the pipe contacts only the corrugated inner layer pipe 20. Composed of joint structure 10 of metallic flexible tube, characterized in that the so that.
[0006]
Embodiments and Embodiments of the Invention
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG.1 and FIG.2 has shown the joint part structure 10 of the metal flexible pipe based on the Example of this invention. In the figure, a joint structure 10 of a metal flexible tube is composed of a metal flexible tube 12 having an inner layer tube 20 and an outer layer tube 22 formed by corrugating a pipe formed by stacking two thin plates into a cylindrical shape. In the joint portion, the length of the inner layer tube 20 in the expansion / contraction direction is longer than the length of the outer layer tube 22 in the expansion / contraction direction so as to form an inner layer tube extension. And it has the seal part 19 provided with the seal surface part 19a formed by inserting and penetrating the inner layer pipe extension part into the mounting hole 16 of the joint metal fitting 14, and bending the penetration end part, and the seal surface part 19a is formed only by the inner layer pipe 20. It is formed and configured.
[0007]
As shown in FIG.1 and FIG.2, the metal flexible tube 12 is provided with the bellows part 13 shape | molded by the waveform. In this embodiment, the bellows portion 13 includes an inner layer tube 20 and an outer layer tube 22, and is formed as an integral structure by superimposing two thin plates in a cylindrical shape. The inner layer tube 20 and the outer layer tube 22 are made of a thin pipe-like stainless material or the like, and the outer layer tube 22 is formed of a SUS304 material. For example, the inner layer tube 20 is formed of a SUS316L material particularly excellent in corrosion resistance. The bellows portion 13 is a U-shaped and inverted U-shaped pipe at equal pitch intervals by using a known roll forming method or hydraulic forming method, etc., by forming a cylindrical pipe by laminating two metal thin plates, an inner layer tube 20 and an outer layer tube 22. The shape is repeated continuously to form a waveform. An inner layer tube extension portion 26 of the inner layer tube 20 is formed on the end side of the metal flexible tube 12 having the bellows portion 13, and the length of the inner layer tube 20 in the expansion / contraction direction is longer than the length of the outer layer tube 22 in the expansion / contraction direction. It is formed. A joint fitting 14 to be described later is arranged on the end side of the metal flexible tube 12. The inner layer pipe extension 26 is inserted into the fitting hole of the joint fitting 14, and the extension end is bent to form the seal part 19. The joint fitting 14 and the seal part 19 are used as a joint part 24.
[0008]
The joint fitting 14 is made of a metal material having corrosion resistance, and is a thick disk and is provided with a mounting hole 16 in the center. In the present embodiment, the length of the mounting hole 16 in the axial direction (thickness direction of the joint fitting) is formed longer than the regular pitch interval of the corrugated portion of the bellows portion 13. In FIG. 2, R-shaped portions 17 formed in a substantially arc shape are provided at both ends of the inner wall of the mounting hole 16. Therefore, when the metal flexible tube 12 is mounted in the mounting hole 16 as will be described later, the inner layer tube 20 and the outer layer tube 22 are smoothly formed into the R shape portion 17 because the R shape portion 17 has an arc shape. Bend along. In FIG. 1, the joint fitting 14 is provided with a plurality of connection holes 28 in a circumferential shape. The coupling hole 29 of another coupling fitting 32 is aligned with the coupling hole 28 and a bolt 34 or the like is inserted, and the coupling fittings 14 and 32 are fastened and fixed with a packing 36 made of rubber or asbestos material interposed. Will be joined.
[0009]
As described above, the inner layer tube 20 of the metal flexible tube 12 forms the inner layer tube extension 26 so that the length of the inner layer tube 20 in the expansion / contraction direction is longer than the length of the outer layer tube 22 in the expansion / contraction direction. The metal flexible tube 12 is mounted by inserting the inner layer tube extension 26 of the inner layer tube 20 into the mounting hole 16 of the fitting 14 and penetrating it. In FIG. 2, the metal flexible tube 12 is inserted into the mounting hole 16, and the side surface side of the first wave portion 15 of the bellows portion 13 is brought into contact with the side surface of the fitting 14. In this state, the end portion 42 b of the outer layer pipe 22 is disposed so as to be positioned at a substantially middle position in the axial length of the mounting hole 16 of the joint fitting 14. A portion of the inner layer tube provided longer than the end portion 42 b of the outer layer tube 22 forms the inner layer tube extension 26.
[0010]
Then, the penetrating end of the inner pipe extension 26 inserted and penetrated into the mounting hole 16 of the fitting 14 is bent to form the seal portion 19. In the embodiment, the seal portion 19 is formed by bending the through end portion of the inner layer pipe extension portion 26 and expanding it in the enlargement direction. Furthermore, it is formed by being folded back into a substantially U-shaped cross section so that the opening side is directed to the center direction of the inner layer pipe 20 continuously from the enlarged portion 18. The folded portion is a seal surface portion 19a, and the outer surface is a seal surface S. A seal 36 for watertightness is applied in close contact with the seal surface S, and the joint fitting 14 is connected to another joint fitting 32.
[0011]
That is, the inner layer pipe extension 26 is bent along the seal receiving surface 14a as a flat surface on the side surface side of the fitting 14 from the insertion direction to form the enlarged portion 18, and the height of the corrugated crest of the bellows portion 13 is formed. It is folded at a certain position. The joint bracket 14 is continuously bent from the enlarged portion 18 of the inner layer pipe extension 26 arranged along the seal receiving surface 14a toward the center of the inner layer pipe 20, and is bent into a substantially U-shaped cross section to form the seal receiving surface 14a. A double layer is formed closely. In FIG. 2, the inner layer tube 20 and the outer layer tube 22 are in a stacked state up to a substantially intermediate position of the axial length of the mounting hole 16, and the end portion 42b of the outer layer tube 22 is mounted at this substantially intermediate position. It stays in close contact with the inner wall surface of the hole 16. In the seal portion 19, the enlarged portion 18 and the seal surface portion 19 a that are continuously provided are folded back in a U shape, and are crushed at the folded position to be bent into a double U shape.
[0012]
As described above, since the end portion 42b of the outer layer tube 22 is disposed at a substantially middle position in the axial direction of the mounting hole 16 of the fitting 14, the seal surface portion 19a of the metal flexible tube 12 is the inner layer tube. It is formed only by the inner layer pipe 20 provided with the extension part 26. Therefore, only the inner layer tube 20 is in contact with the seal receiving surface 14a. The end 42a of the inner tube extension 26 is smoothly bent toward the inside of the hole along the R-shaped portion 17 formed in a substantially arc shape of the mounting hole 16. Thus, only the inner layer tube 20 is in close contact with the seal receiving surface 14a of the joint fitting 14, and the end portion 42b of the outer layer tube 22 terminates in, for example, the mounting hole 16 of the joint fitting 14, so the outer layer tube 22 is formed in the inner layer. The tube 20 is always covered, so that the working fluid does not contact the outer layer tube 22 at all. Further, since the seal portion 19 of the metal flexible tube 12 is formed only by the inner layer tube 20, only the inner layer tube 20 having corrosion resistance comes into contact with the fluid to be used because the liquid contact surface is only the inner layer tube. Corrosion resistance can be greatly improved.
[0013]
With regard to joint connection, the joint fitting and the other joint fitting are fastened with a bolt 34 or the like via the packing 36, so that the seal portion 19 is fixed in close contact with each other, and watertightness can be reliably maintained.
[0014]
Next, the case where the joint part structure 10 of the metal flexible pipe of this invention is used is demonstrated. Since the joint part structure 10 of the metal flexible pipe is mounted on a mechanical facility or the like and connected to another joint fitting, the seal part 19 of the joint fitting 14 of the metallic flexible pipe 12 is made of rubber or asbestos material. Another joint fitting 32 is attached to the seal portion 19 of the joint fitting 14 via the packing 36. The joint fittings 14 and 32 are joined by fastening and fixing the joint fittings by inserting and screwing bolts or the like into the respective connection holes 28 and 29. At this time, since the seal portion 19 is formed in a structure in which only the inner layer pipe 20 is exposed, a high-temperature fluid or a fluid using a chemical solution is always in contact with the inner layer pipe 20 having excellent corrosion resistance, and the fittings are connected to each other. The corrosion resistance of the joint portion can be greatly improved. Further, since the seal portion 19 of the joint fitting 14 of the present invention is formed by folding only the inner layer pipe 20 to form the seal portion 19, there is no gap between the inner layer pipe 20 and the outer layer pipe 22, and the fluid used in the gap Therefore, the corrosion resistance of the metal flexible tube 12 as a whole can be reliably improved. The other fitting 32 may be a fitting having a bellows portion or a fitting having a pipe having another material and shape.
[0015]
Further, in the present invention, the inner tube extension 26 is formed in the metal flexible tube 12 having the inner tube 20 and the outer tube 22 formed by corrugating a pipe formed by stacking two thin plates into a cylindrical shape. The length of the inner layer pipe 20 in the expansion / contraction direction is longer than the length of the outer layer pipe 22 in the expansion / contraction direction, the inner layer pipe extension 26 is inserted through the fitting hole 16 of the fitting 14, and the through end is folded back to seal part 19 The seal portion 19 is joined to another joint fitting 32 to be coupled. In the connection method of the joint part of the metal flexible pipe 12, the joint part 24 is formed only from the inner layer pipe 20 excellent in corrosion resistance. For this reason, when the joint fitting 14 of the joint portion 24 and the other joint fitting 32 are fastened and fixed with bolts or the like, the internal fluid always contacts only the inner layer pipe 20 having excellent corrosion resistance, and the entire metal flexible pipe 12 Thus, it is possible to reliably maintain the corrosion resistance.
[0016]
【The invention's effect】
As described above, according to the joint structure of a metal flexible tube of the present invention, a metal pipe having an inner layer tube and an outer layer tube formed by corrugating a pipe formed by stacking two thin plates into a cylindrical shape. In the joint portion of the flexible tube, the length of the inner layer tube is formed to be longer than the length of the outer layer tube in the stretch direction so as to form the inner layer tube extension portion, and the inner layer tube extension portion is inserted and penetrated into the fitting hole of the fitting fitting. Since the penetrating end part is folded back to form a seal part, and the seal part is formed only by the inner layer pipe, only the inner layer pipe having corrosion resistance is always kept in contact with the internal fluid and can be connected to other fittings. Thus, the corrosion resistance of the metal flexible tube at the joint fitting portion can be greatly improved. In addition, since the internal fluid is not in contact with the gap between the inner layer tube and the outer layer tube, even if an outer layer tube having a lower corrosion resistance than the inner layer tube is used, the inner fluid does not contact the outer layer tube, and the corrosion resistance as a metal flexible tube Can be maintained well.
[0017]
Further, since the seal portion is formed by bending the inner layer tube extension portion into a substantially U-shaped cross section so that the opening side is directed to the center direction of the inner layer tube, only the inner layer tube having corrosion resistance in connection with other fittings is used. It is possible to always contact the internal fluid, and at the same time, since the overlap gap between the inner layer tube and the outer layer tube does not contact the inner fluid at all, the corrosion resistance of the entire metal flexible tube can be reliably improved.
[0018]
Further, according to the method for connecting the joint portion of the metal flexible tube of the present invention, the metal flexible tube having the inner layer tube and the outer layer tube formed by corrugating a pipe formed by stacking two thin plates into a cylindrical shape. In the pipe, the length of the inner layer pipe is formed to be longer than the length of the outer layer pipe so as to form the inner layer pipe extension, and the inner layer pipe extension is inserted and penetrated into the fitting fitting mounting hole. Is used as a seal part, and this seal part is joined to another joint fitting so that the joint is connected, so that only the inner layer pipe having corrosion resistance is always in contact with the internal fluid and greatly improves the corrosion resistance of the metal flexible pipe as a whole. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a partially enlarged cross-sectional explanatory view of a main part showing a joint structure of a metal flexible pipe according to an embodiment of the present invention.
2 is a partially omitted enlarged cross-sectional explanatory view of the joint surface of the joint structure of the metal flexible tube of FIG. 1;
FIG. 3 is a partially omitted cross-sectional view showing a joint structure of a conventional metal flexible tube.
FIG. 4 is a partially omitted enlarged sectional view showing a joint surface of a joint structure of a conventional metal flexible tube.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Joint part structure of metal flexible pipe 12 Metal flexible pipe 14 Joint metal fitting 16 Mounting hole 19 Seal part 19a Seal surface part 20 Inner layer pipe 22 Outer layer pipe 26 Inner layer pipe extension part S Seal surface

Claims (1)

A metal flexible pipe joint structure in which a two- ply thin cylindrical pipe is formed into a waveform in which peaks and valleys are continuously repeated , and a corrugated inner layer pipe and a corrugated outer layer pipe are integrated ,
To form the inner layer tube extension part, the length of the stretched direction of one end of the corrugated inner layer tube is made longer than the length of the stretched direction of one end of the corrugated outer layer tube of the same overlapping portion ,
Insert and penetrate the inner pipe extension into the fitting hole of the fitting so that the fitting hole of the fitting is fitted in the valley on the final end side of the metal flexible pipe ,
And a seal portion for close contact with the front portion bent to the side surface of the joint fitting superimposed folded its penetrating end in a U-shape,
One end of the length of the corrugated outer layer pipe in the expansion / contraction direction is terminated at an intermediate position of the axial length of the fitting fitting mounting hole so that the internal fluid in the pipe contacts only the corrugated inner layer pipe . Flexible pipe joint structure.

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