JP2007046728A - Expansion joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an expansion joint capable of absorbing large axial displacement without accumulating fluid. <P>SOLUTION: This expansion joint comprises a cylindrical body 2 connected with piping 20 at its one end side, a guide ring 4 axially slidably supported on an outer peripheral face of the cylindrical body 2, and a deformed pipe 3 composed of a first cylindrical portion 31 connected with the guide ring 4 and externally mounted at the other end side of the cylindrical body 2, an intermediate portion 32 having a reduced diameter continuously from the first cylindrical portion, and a second cylindrical portion 34 connected with piping 12 in such a state that the first cylindrical portion 31 and the second cylindrical portion 33 have the eccentric shapes. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an expansion joint used for, for example, a drainage pipe in which high-temperature drainage flows and the length of the pipe changes.

  In normal piping equipment, various fluids (air, fuel gas, water vapor, water, oils, etc.) of 220 ° C or less flow in the piping, so the piping material is selected according to the type of fluid and the operating pressure. Is done. As an example, in the drainage pipe, from the viewpoint of corrosion resistance, the joint used for the pipe and its connecting portion is formed of a metal material having corrosion resistance typified by stainless steel. For example, in food factory drainage piping, high-temperature wastewater containing chlorine-based cleaning agents such as hypochlorous acid flows, but since the operating temperature range is as wide as 0 to 90 ° C, in order to absorb the expansion and contraction due to thermal expansion, A joint having an expansion / contraction function (hereinafter referred to as an expansion joint) has been proposed and put into practical use. For example, the Air Conditioning and Sanitary Engineering Society standards include rubber displacement absorbing pipe joints, metal displacement pipe joints using bellows, sleeve-type expansion pipe joints that allow the sleeve to enter and exit the body, and mechanical types using ball joints. A displacement absorbing fitting is described.

  In order to put these expansion joints into practical use, a structure in which the above standards are improved has also been proposed. For example, in Patent Document 1, in a joint of a type in which an inner cylinder is fitted to a bellows via a circumferential clearance, a cylinder part of a flange connected to an upstream pipe and a cylinder part of a flange connected to a downstream pipe The straight pipe portions at both ends of the bellows are fitted inwardly, and the end edges of the straight pipe portions are overlapped on the seat plate overlapped on the outer end faces of both flanges, and are welded together over the entire circumference. An expansion pipe joint in which the flange portion of the flange is welded to the seat plate is described. According to Patent Document 1, since the inner cylinder is welded to the seat plate separately from the bellows, fluid leakage is prevented.

  Further, Patent Document 2 discloses that even when the pressure head is low and the hydrodynamic gradient is small, the inner pipe coaxial with the outer pipe can be rotated with respect to the outer pipe so that the smooth flow is not hindered. In addition, a flexible eccentric joint is described in which the insertion amount is variable and the end tubes are inserted into the outer tube and the inner tube in a rotatable state, and the end tubes are eccentric from each other.

JP-A-7-127777 (page 3-4, FIGS. 1 and 2) JP 2004-239354 (page 4, FIG. 2)

  However, the conventional joint is desired to be improved in the following points. According to the expansion pipe joint described in Patent Document 1, it is possible to absorb a large displacement in the axial direction of the pipe, but there is a portion (dead space) where fluid does not flow inside the joint. Become. That is, a part of the fluid flowing out from the inner cylinder flows into the gap between the inner cylinder and the bellows and stays there, so that there is a problem that the accumulated drainage is easily spoiled and the pipe is easily corroded. Further, the joint described in Patent Document 2 can absorb misalignment at the position of the pipe joint by rotation between the outer pipe and the inner pipe, and also changes the amount of insertion of the inner pipe into the outer pipe. Although it is possible to absorb errors in the expansion / contraction direction and secular changes at the pipe joint position, when the pipe length fluctuates greatly due to thermal expansion, it is difficult to absorb such a large displacement. is there.

  An object of the present invention is to solve the above-described problems and provide an expansion joint that can absorb a large displacement in the axial direction of a pipe without stagnation of fluid.

  In order to achieve the above object, the expansion joint of the present invention includes a cylindrical body having a pipe connected to one end thereof, a guide ring supported on an outer peripheral surface of the cylindrical body so as to be slidable in the axial direction, and the guide A first cylindrical portion that is connected to the ring and is sheathed on the other end side of the cylindrical body, an intermediate portion having a portion continuously reduced in diameter from the first cylindrical portion, and a second cylindrical portion having a pipe connected to the end portion. In addition, the first cylindrical portion and the second cylindrical portion include a deformed tube having an eccentric shape.

  In the present invention, it is preferable that the deformed tube has a shape such that the intermediate portion is formed in a substantially cone shape and an inner surface near the bottom portion extends substantially horizontally.

  In the present invention, the guide ring and the first cylindrical portion may be flange-coupled.

  In the present invention, the end portion of the guide ring can be fixed to the first cylindrical portion.

  In the present invention, the guide ring preferably includes a seal member and a slide ring that circumscribe the cylinder.

  According to the present invention, by providing the guide ring connected to the deformed pipe on the outer periphery of the cylindrical body, the axial movement of the cylindrical body and the deformed pipe is allowed, so that the pipe is greatly displaced in the axial direction. Even it can be absorbed. In addition, since the first cylindrical portion that is externally mounted on the cylindrical body and the second cylindrical portion that communicates with the first cylindrical portion via the intermediate portion have an eccentric shape, drainage is retained near the bottom of the inner peripheral surface of the deformed pipe. The phenomenon can be prevented.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view of the expansion joint according to the first embodiment of the present invention, and FIG. 2 is an arrow view of FIG. 1 viewed from the A direction.

  As shown in FIG. 1, the expansion joint 1 includes a cylindrical body 2 connected between a pipe 10 and a pipe 12 where drainage flows in the direction of the arrow X, and a pipe 10 having a plug flange 11, and a plug flange. 13, a deformed pipe 3 connected to a pipe 12, a guide ring 4 supported on the outer peripheral surface of the cylindrical body 2, a pipe 10 and a cylindrical body 2, a cylindrical body 2 and a deformed pipe 3, and a deformed pipe 3 and a pipe 12. Are provided with fastening members 7a, 7b and 7c. Each part of the expansion joint 1 is configured as follows.

The cylindrical body 2 has an axis O ₁ having the same diameter as the pipe 10 and concentric with the pipe 10. The insertion flange 21 is fixed to one end portion, and a plurality of stoppers 22 (see FIG. 2) are fixed to the other end portion. ing.
Profiled tube 3, there continuously from the first cylindrical portion 31 surrounding the has a shaft center O ₂ which is eccentric by the distance e ₁ with respect to the axis O ₁ of the cylinder 2 and the other end of the cylindrical body 2 The intermediate portion 32 to be reduced in diameter and the second cylindrical portion 33 having an axis O ₃ eccentric by a distance e ₂ (<e ₁ ) with respect to the axis O ₁ of the cylindrical body 2 and having the same diameter as the pipe 12. Has been. That is, the deformed tube 3 has a shape in which the first cylindrical portion 31 and the second cylindrical portion 33 are eccentric. Moreover, the intermediate part 32 is formed in a substantially cone shape as a whole (a part excluding the vicinity of the bottom part of the entire circumference). Furthermore, the deformed pipe 3 is formed so that the inner surface near the bottom extends substantially horizontally (may be a gentle downward slope) along the flow direction of the drainage over the entire length thereof. An insertion flange 34 is fixed to the end of the first cylindrical portion 31, and an insertion flange 35 is fixed to the end of the second cylindrical portion 32. Each flange is provided with a plurality of holes at equal angular intervals in the circumferential direction, and bolts are inserted therein. For example, as shown in FIG. 2, the flange 13 is provided with eight bolt holes 131, and the flange 34 is provided with four bolt holes 341.

  The guide ring 4 supported on the outer peripheral surface of the cylindrical body 2 is disposed between the pair of slide rings 5a and 5b that contact the outer peripheral surface of the cylindrical body 2 and allow relative movement thereof, and the cylinder 20 And a pair of seal members 6a and 6b that are in close contact with the outer peripheral surface of the. The blind flange 41 is fixed to the outer peripheral surface of the guide ring 4, and the insertion flange 34 is coupled thereto, whereby the deformed pipe 3 can move in the axial direction in synchronization with the guide ring 4. The blind flange 41 has a seal member 6 c fitted on the end face on the side facing the insertion flange 34. The number of the slide ring and the seal member is not limited to a pair, and may be one or three or more.

  In the present invention, the size and material of each member constituting the joint may be selected according to the type of fluid, pressure and temperature, and the length and diameter of the pipe. For example, in a pipe through which high temperature drainage (maximum temperature: 90 ° C., pressure: 0.5 to 1 MPa) flows, pipes 10 and 12, flanges including flange 11, cylindrical body 2, deformed pipe 3, guide ring 4 and Each fastening member is preferably formed of a metal material having corrosion resistance such as stainless steel (austenitic stainless steel such as SUS304). The slide rings 5a and 5b are made of a polybutylene terephthalate (PBT) having a coefficient of dynamic friction of 0.14 for a crystalline plastic having a low frictional resistance and a high deflection temperature, such as steel, and a deflection temperature (0.45 MPa) of 154 ° C. ). Seal members 6a, 6b and 6c include olefin rubbers such as ethylene-propylene rubber (EPDM) and fluorine rubbers such as vinylidene fluoride rubber (FKM) which are excellent in heat resistance and chemical resistance (particularly against chlorine). It is preferable to use an O-ring consisting of

  According to said expansion joint 1, the piping 10 and the piping 12 can be connected in the following procedure. The cylindrical body 2 to which the stopper 22 is welded covers the guide ring 4 in which the blind flange 41 is welded and the slide rings 5a and 5b and the seal members 6a and 6b are fitted, and is inserted into the end of the cylindrical body 2. The flange 21 is welded. Further, the insertion flanges 34 and 35 are welded to both ends of the deformed pipe 3. Next, the flange 11 and the insertion flange 21 are coupled by a fastening member 7a including a bolt 71a and a nut 72a, and the insertion flange 35 and the flange 13 are coupled by a fastening member 7b including a bolt 71b and a nut 72b. Finally, the piping construction is completed by connecting the blind flange 41 and the insertion flange 34 with the fastening member 7c including the bolt 71c and the nut 72c.

According to the piping structure shown in FIG. 1, for example, when the pipe 10 and the pipe 12 are thermally expanded due to the flow of a high-temperature fluid, the distance S between the end face (left side in the figure) of the guide ring 4 and the end face of the insertion flange 21. by a length corresponding to _1, since the relative axial movement between the cylindrical body 2 and the profiled tube 3 is allowed, the elongation of the S ₁ minute piping is absorbed. In contrast, as the temperature of the fluid is lowered, if the pipe 10 and the pipe 12 is contracted, the end surface of the guide ring 4 (right side in the drawing) by a distance length corresponding to S ₂ between the stopper 22 since the relative axial movement between the cylindrical body 2 and the profiled tube 3 is allowed, the contraction of S ₂ minutes piping is absorbed. In particular, since the guide ring 4 is supported on the outer peripheral surface of the cylindrical body 2 via a pair of slide rings 5a and 5b juxtaposed at a predetermined interval, the cylindrical body 2 and the deformed tube 3 are parallel to each other. It is possible to move and smooth relative movement is guaranteed.

  Further, the deformed pipe 3 has a shape in which the intermediate portion 32 is formed between the first cylindrical portion 31 and the second cylindrical portion 33 and the first cylindrical portion 31 and the second cylindrical portion 33 are eccentric. Even if the wastewater temporarily flows between the first cylindrical portion 31 and the cylindrical body 2, the wastewater immediately flows into the second cylindrical portion 33. Therefore, no stagnation of the waste water occurs in the joint, so that the sewage of the waste water and the corrosion of the piping due to the stagnation of the waste water can be prevented in advance. In particular, the intermediate portion 32 existing between the first cylindrical portion 31 and the second cylindrical portion 33 is formed in a substantially cone shape, and the inner surface near the bottom is substantially along the flow direction of the drainage over the entire length of the deformed tube 3. Therefore, the step is not formed in the joint 1 so as to inhibit the flow of the waste water, and the stay of the waste water can be prevented more reliably.

  The joint of the present invention is not limited to the above-described structure, and various modifications are possible. For example, the structure shown in FIGS. 3 and 4 can be used. FIG. 3 is a longitudinal sectional view of the expansion joint according to the second embodiment of the present invention, and FIG. 4 is an arrow view of FIG. 1 viewed from the B direction. Since the expansion joint 1 is configured in the same manner as that shown in FIGS. 1 and 2 except that the connection structure between the cylindrical body 2 and the deformed pipe 3 is different, the same parts as those in FIGS. 1 and 2 have the same reference numerals. The description is omitted. This expansion joint 1 has a structure in which an upper half section having a substantially L-shaped cross section is used as a guide ring 4 and its upper end 41 is fixed to the deformed pipe 3 by welding, for example. According to this structure, the flange fixed to one end portion of the cylindrical body 2 and the flange fixed to one end portion of the deformed pipe 3 are not required, and the number of parts can be reduced.

In FIG. 1, a cylindrical body 2 having a length of 165 mm and a diameter of 150 A (nominal diameter, the same applies hereinafter), a first cylindrical part 31 having a length of 50 mm and a diameter of 200 A, and a second cylindrical part 33 having a length of 50 mm and a diameter of 150 A are provided. SUS304 having a diameter of 150A (thermal expansion) by using the deformed pipe 3 having a total length of 150 mm with e ₁ = 21.55 mm and e ₂ = 4 mm and S ₁ = 50 mm and S ₂ = 22 mm Pipes 10 and 12 having a coefficient of 17.3 × 10 ⁻⁶ / K) were connected. In this expansion joint 1, each flange including the insertion flange 21, the cylindrical body 2, the guide ring 4, the deformed pipe 3, and the stopper 22 are formed of SUS304, and slide rings 5 a and 5 b made of PBT and an EPDM O-ring are used. Seal members 6a, 6b and 6c to be used were used.

When the total length of the pipe is 60 m and the temperature of the drainage is changed in the range of 0 to 95 ° C., the elongation of the pipe is theoretically about 100 mm. According to the expansion joint 1 described above, the relative movement in the axial direction between the cylindrical body 2 and the deformed pipe 3 is allowed. Therefore, by setting the dimensions of each part of the joint as described above, the elongation of 100 mm is absorbed. be able to. Moreover, since the deformed tube 3 is eccentric with respect to the cylindrical body 2 and the intermediate portion 32 is formed between the first cylindrical portion 31 and the second cylindrical portion 33, the drainage does not stay in the joint, Corrosion of drainage and piping can be prevented. Further, since the second cylindrical portion 33 is eccentric with respect to the cylinder 2 by a distance e ₁ , there is a minute size of 0.4 mm at the maximum near the lowest point of the joint (arc-shaped region indicated by F in FIG. 2). However, since the guide ring 4 is provided with the two seal members 6a and 6b, it is possible to reliably prevent the drainage from leaking out of the joint.

It is a longitudinal cross-sectional view of the expansion joint concerning the 1st Embodiment of this invention. It is arrow sectional drawing which looked at FIG. 1 from the A direction. It is a longitudinal cross-sectional view of the expansion joint concerning the 2nd Embodiment of this invention. It is arrow sectional drawing which looked at FIG. 1 from the B direction.

Explanation of symbols

1: expansion joint,
2: cylindrical body, 21: insertion flange, 22: stopper 3: deformed pipe, 31: first cylindrical portion, 32: intermediate portion, 33: second cylindrical portion, 34, 35: insertion flange 4: guide ring, 41: Blind flange, 42: upper end portions 5a, 5b: slide rings 6a, 6b, 6c: seal members 7a, 7b, 7c: fastening members, 71a, 71b, 71c: bolts, 72a, 72b, 72c: nuts 10, 12: piping 11, 13: Flange

Claims (5)

A cylindrical body to which piping is connected to one end side, a guide ring supported to be slidable in the axial direction on the outer peripheral surface of the cylindrical body, and connected to the guide ring and sheathed on the other end side of the cylindrical body A first cylindrical portion, an intermediate portion continuously reduced in diameter from the first cylindrical portion, and a second cylindrical portion having a pipe connected to an end thereof, and the first cylindrical portion and the second cylindrical portion are eccentric. An expansion joint comprising a deformed pipe having the same. 2. The expansion joint according to claim 1, wherein the deformed pipe has a shape in which the intermediate portion is formed in a substantially cone shape and an inner surface near a bottom portion thereof extends substantially horizontally. The expansion joint according to claim 1, wherein the guide ring and the first cylindrical portion are flange-coupled. The expansion joint according to claim 1, wherein the guide ring has an end portion fixed to the first cylindrical portion. The expansion joint according to any one of claims 1 to 4, wherein the guide ring includes a seal member and a slide ring that circumscribe the cylindrical body.

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