JP4070613B2 - Metal expansion pipe joint - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal expansion pipe joint that absorbs the expansion and contraction amount of a metal pipe or duct through which a corrosive fluid flows.
[0002]
[Prior art and problems]
Although a publicly known literature cannot be specifically mentioned as a conventional metal expansion pipe joint, for example, a conventional metal expansion pipe joint used for a combustion exhaust gas duct of a garbage incinerator is a stainless steel bellows, It is comprised by the stainless steel joining flange attached to the both ends of this. Thus, for example, the combustion exhaust gas at 300 to 400 ° C. that circulates inside the joint contains corrosive components that easily corrode metals such as sulfuric acid-based components and hydrochloric acid-based components. When the inner peripheral surface side of the bellows is exposed to the gas flow path as described above, there is a problem that the bellows corrodes in a short period of time and the joints are frequently replaced.
[0003]
In view of the above problems, an object of the present invention is to provide a metal expansion joint that can prevent corrosion due to a metal corrosive medium and extend the service life.
[0004]
[Means for Solving the Problems]
The invention according to claim 1, a metal bellows 2, in the metal expansion joints formed of an adhesive flange 3,3 Metropolitan attached to both ends of this, the bellows 2, the inner circumferential surface of the bellows 2 The covering fluororesin tubular sheet 4 is inserted, and both ends of the tubular sheet 4 are attached to the flange 3 via gaskets 17. the inner peripheral surface side, unlike the diameter from one another a metal sleeve 5,6 covering the cylindrical seat 4, of which one sleeve 5, about the length of the length is the metallic bellows 2 The other sleeve 6 is formed so that its length is as short as the length of the joining flange 3 and between the outer peripheral surface of the small diameter side sleeve 5 and the inner peripheral surface of the large diameter side sleeve 6. a pair of sleeves gap is formed 5 Characterized by comprising providing a 6 telescopically.
[0005]
According to a second aspect of the present invention, in the metal expansion joint according to the first aspect, a heat insulating material K is interposed between the tubular sheet 4 and the sleeves 5 and 6.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a half sectional front view of a metal expansion joint 1A according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a portion indicated by an arrow A in FIG. This metal expansion pipe joint 1A includes a cylindrical metal bellows 2, joining flanges 3 and 3 attached to both ends of the bellows 2, and a fluororesin tube covering the inner peripheral surface of the metal bellows 2. Sheet-like sheet 4, a pair of metal sleeves 5 and 6 disposed in a nested manner so as to cover tubular sheet 4 on the further inner peripheral side of tubular sheet 4, fluororesin-made tubular sheet 4 and the above-mentioned It consists of the heat insulating material K interposed between the sleeves 5 and 6.
[0007]
The metal bellows 2 is formed in a cylindrical bellows shape having a crest portion a and a trough portion b made of a stainless material having a thickness of 0.3 to 3.0 mm, and can be expanded and contracted in the axial direction. . The joining flanges 3 respectively attached to both ends of the bellows 2 are made of stainless steel, and as can be seen from FIG. 2, an end tube 3o that can be externally fitted to the trough b at the end of the bellows 2 is integrated. Is formed. A large number of bolt insertion holes 11 are provided in the joining flange 3 at a constant pitch in the circumferential direction.
[0008]
The fluororesin cylindrical sheet 4 covering the inner peripheral surface of the metal bellows 2 has a thickness of 0.2 to 1 by, for example, Teflon (registered trademark) which is a copolymer of tetrafluoroethylene and hexafluoropropylene. Corrosion of the bellows 2 by a metal corrosive medium of combustion exhaust gas due to its excellent heat resistance and corrosion resistance, which is formed at a diameter of about 0.0 mm and approximately the same as the diameter of the bellows 2 side of the bellows 2 Can be prevented. The length of the tubular sheet 4 is longer than the normal length of the metal bellows 2.
[0009]
A pair of metal sleeves 5 and 6 provided in a nested manner so as to cover the tubular sheet 4 on the further inner peripheral side of the tubular sheet 4 are each formed in a cylindrical shape by a stainless material having a thickness of about 2 mm. Thus, one sleeve 5 has an outer diameter that is sufficiently smaller than the inner diameter of the cylindrical sheet 4 and has a length that is about the length of the metal bellows 2, and the other sleeve 6 has an inner diameter that is the above-described sleeve 5. The mounting flange is formed so as to be shorter than the outer diameter of the joint flange 3 and about the length of the joint flange 3, and can be joined to the joint surface side of the joint flange 3 at one end of each of the sleeves 5 and 6. 7 and 8 are fixed by welding. Each of the mounting flanges 7 and 8 is provided with a bolt insertion hole 12 at a position corresponding to the bolt insertion hole 11 of the joining flange 3.
[0010]
The heat insulating material K is made of, for example, a ceramic blanket, and is enclosed in a bag 9 made of glass cloth or ceramic cloth and formed in a substantially ring shape.
[0011]
In assembling the metal expansion joint 1A made of the above-described components, first, as schematically shown in FIG. 1, for example, four angle pieces 13 with bolt insertion holes are provided in each circumferential direction 90 in the circumferential direction 90. After welding at a predetermined interval and fitting both the flanges 3 and 3 to both ends of the bellows 2, a through bolt 14 is inserted between the opposing angle pieces 13 and 13 of the both flanges 3 and 3. Then, the joint flanges 3 and 3 are held at predetermined intervals by the nuts 15 and 16 screwed to the nuts 15 and 16, and the joint flanges 3 and 3 are fixed to both ends of the bellows 2.
[0012]
In this way, the fluororesin tubular sheet 4 covering the inner peripheral surface of the bellows 2 is inserted into the bellows 2 in which both the joining flanges 3 and 3 are fixed to both ends, and both ends 4a and 4a of the tubular sheet 4 are inserted. Each end 4a of the tubular sheet 4 thus bent is sandwiched between two ceramic cloth gaskets 17 and 17 and adhered to each other with an adhesive, and one side of the gaskets 17 and 17 is attached. It adheres to the joining surface of the flange 3 for joining with an adhesive agent.
[0013]
And after inserting the ring-shaped heat insulating material K enclosed by the bag 9 in the inner peripheral side of the cylindrical sheet | seat 4, on a further inner peripheral side of this ring-shaped heat insulating material K, a pair of metal sleeves 5, 6 is inserted from both sides of the joint flanges 3 and 3, the sleeves 5 and 6 are bonded to the heat insulating material K with an adhesive, and the mounting flanges 7 and 8 of the sleeves 5 and 6 are respectively connected to the tubular sheet 4. The end portions 4a are applied to the outer surfaces of the gaskets 17 and 17, and the gaskets 17 and 17 are sandwiched between the mounting flanges 7 and 8 and the joining flange 3, thereby Finish assembly. This state is shown in FIG.
[0014]
When the assembly of the expansion pipe joint 1A thus assembled is used, for example, as a joint of a combustion exhaust gas duct of a refuse incinerator, each end of the expansion pipe joint 1A is connected to the combustion exhaust gas duct 18 as shown in FIG. What is necessary is just to connect to the flange 19 for joining. In this connection, bolts 20 are joined to the gaskets 17, 17, the end 4 a of the cylindrical sheet 4, another gasket 22, and the duct 18 from each joining flange 3 of the expansion joint 1 </ b> A as shown in the figure. What is necessary is just to penetrate through the flange 19 and tighten with the nut 21. After the installation of the expansion pipe joint 1A to the combustion exhaust gas duct 18 is thus completed, the bolts 14 and the nuts 15 and 16 that have held the both flanges 3 and 3 of the expansion pipe joint 1A at a predetermined interval are removed. .
[0015]
According to the metal expansion joint 1A of the present invention used as a joint for a combustion exhaust gas duct of a refuse incinerator as described above, a fluororesin tube covering the inner peripheral surface of the bellows 2 in the metal bellows 2 Since the cylindrical sheet 4 is provided, and the metal sleeves 5 and 6 are provided on the inner peripheral surface side of the cylindrical sheet 4 via the heat insulating material K, the inside of the joint 1A is heated with high-temperature exhaust gas, particularly sulfuric acid. Even if an exhaust gas containing a metal corrosive component such as a system component or a hydrochloric acid component circulates, the metal bellows 2 has a heat insulating material K having a large heat insulating performance and an excellent heat insulating property and corrosion resistance. Since it is separated by the fluororesin tubular sheet 4 having the above, it is not affected by the high heat of the exhaust gas and the metal corrosive component, and therefore it is hardly corroded and can be used for a long period of time. It can be extended longer.
[0016]
In this case, the heat insulating material K and the fluororesin tubular sheet 4 are held at positions along the inner peripheral surface of the bellows 2 by the metal sleeves 5 and 6 disposed on the inner peripheral side of the heat insulating material K. Therefore, it does not sag and hang down or deform unexpectedly.
[0017]
When the ducts 18 and 18 connected to both ends of the expansion joint 1A are thermally expanded by high-temperature exhaust gas to cause expansion in the axial direction, the expansion joint 1A is compressed from both ends and contracted by the bellows 2, and the duct 18 will be absorbed. Further, when the temperature of the duct 18 decreases and the duct 18 contracts in the axial direction by stopping the supply of high-temperature exhaust gas into the duct 18, the expansion joint 1 </ b> A is pulled from both ends. Elongation occurs, thereby absorbing the shrinkage of the duct 18.
[0018]
The metal sleeves 5 and 6 are such that one sleeve 5 has a smaller diameter than the other sleeve 6 and both sleeves 5 and 6 are fitted in a nested manner so that the outer peripheral surface of the small diameter side sleeve 5 and the large diameter side sleeve Since a sufficient gap is formed between the inner peripheral surface of the sleeve 6 and the sleeves 5 and 6 are thermally expanded by the circulation of the high temperature exhaust gas, the holding function is maintained without being deformed undesirably. I can do it. In addition, since the pair of sleeves 5 and 6 on both sides are provided, the heat insulating material K and the entire tubular sheet 4 can be reliably held.
[0019]
Further, both end portions 4a and 4a of the tubular sheet 4 are attached to the joining flange 3 and the metal mounting flanges 7 and 8 via gaskets 17, respectively. Airtightness and no direct contact with metal, so there is no damage or damage.
[0020]
FIG. 3 is a partial cross-sectional view of a metal expansion joint 1B according to another embodiment of the present invention, and FIG. 4 is an enlarged view of a portion indicated by an arrow B in FIG. The expansion tube joint 1B is almost the same as the expansion tube joint 1A described with reference to FIGS. 1 and 2, and is slightly different from the expansion tube joint 1A in one end 2a of the metal bellows 2 (see FIG. 4). The bellows end portion 2a is folded in two as shown in FIG. 4, and the bifold portion is sandwiched between the joining flange 3 and the end portion 4a of the fluororesin tubular sheet 4. This is the point of being interposed between the gaskets 17 and 17. By carrying out like this, the edge part of the bellows 2 can be fixed to the flange 3 side for joining. The gaskets 17 and 17 are disposed inside the mounting flange 8 on the sleeve 6 side.
[0021]
Further, the other end portion 2a of the bellows 2 is inserted into the inner peripheral surface of the joining flange 3, and on the other end portion side, a gasket 17 sandwiching the end portion 4a of the tubular sheet 4 is provided. 17 is inserted between the joining flange 3 and the mounting flange 7 on the sleeve 5 side, and is sandwiched by screws 23 screwed into the joining flange 3 from the mounting flange 7 (see FIG. 3). The structure and assembly method of the expansion tube joint 1B other than those described above are substantially the same as those of the expansion tube joint 1A described with reference to FIGS.
[0022]
FIG. 5 is a cross-sectional view of a metal expansion joint 1C according to still another embodiment of the present invention. This expansion tube joint 1C is different from the expansion tube joints 1A and 1B only in that no heat insulating material is interposed between the fluororesin tubular sheet 4 and the metal sleeves 5 and 6. In this way, even if no heat insulating material is interposed between the tubular sheet 4 and the sleeves 5 and 6, when the temperature of the heated fluid flowing through the expansion pipe joint 1C is relatively low, the fluororesin The heat resistance of the tubular sheet 4 itself makes it possible to cope with the heated fluid.
[0023]
In the expansion pipe joint 1C of this embodiment, the metal sleeves 5 and 6 hold the fluororesin cylindrical sheet 4 covering the inner peripheral surface of the metal bellows 2 so that the fluororesin cylindrical sheet 4 does not bend and hang down inward. Playing a role [0024]
Moreover, in embodiment mentioned above, although cylindrical metal expansion-contraction pipe joint 1A, 1B, 1C was demonstrated, this invention is applicable also to a rectangular tube-type expansion pipe joint. In the case of this rectangular tubular expansion joint, the bellows 2, the tubular sheet 4, and the sleeves 5 and 6 are each formed in a rectangular tube shape, and the joining flange 3 is also formed in a square shape.
[0025]
【The invention's effect】
According to the metal expansion joint of the invention according to claim 1, the tubular sheet made of fluororesin covering the inner peripheral surface of the metal bellows is provided, and the tubular sheet is further provided on the inner peripheral surface side of the cylindrical sheet. Since a metal sleeve is provided to cover the pipe, it can be used as an expansion joint for ducts and pipes that flow at high temperatures and contain fluids containing metal corrosive components such as sulfuric acid and hydrochloric acid components. Even if fluid flows inside the expansion joint, the metal bellows is isolated from the fluid by a fluororesin tubular sheet having excellent heat insulation and corrosion resistance. In addition, it is not greatly affected by the metal corrosive components, and therefore hardly corroded, and can be used for a long time, and the service life of the expansion joint can be extended.
[0026]
Further, since the fluororesin tubular sheet is held by a metal sleeve provided on the inner peripheral side of the tubular sheet, the fluororesin tubular sheet does not sag and hang down or deform unexpectedly.
[0027]
Further, according to the metal expansion joint of the present invention, in addition to the effect of the invention according to claim 1, one sleeve of a pair of metal sleeves disposed on the inner peripheral surface side of the cylindrical sheet is the other sleeve. The sleeves are smaller in diameter than the sleeves, and both sleeves are fitted in a nested manner, so that a sufficient gap is formed between the small-diameter side sleeve and the large-diameter side sleeve. Even if the diameter is increased, both sleeves do not interfere with each other, and therefore, the holding function can be maintained without inconvenient deformation. Further, by providing a pair of sleeves on both sides, the entire cylindrical sheet can be securely held.
[0028]
Furthermore, according to the metal expansion / contraction pipe joint of the present invention, the metal sleeves 5 and 6 are configured such that one sleeve 5 is smaller in diameter than the other sleeve 6 and both sleeves 5 and 6 are fitted in a nested manner. Since a sufficient gap is formed between the outer peripheral surface of the small diameter side sleeve 5 and the inner peripheral surface of the large diameter side sleeve 6, it is inconvenient even if both sleeves 5 and 6 are thermally expanded due to the circulation of high temperature exhaust gas. Therefore, the holding function can be maintained.
[0029]
Furthermore, according to the metal expansion / contraction pipe joint of the present invention, since both ends of the fluororesin tubular sheet are attached to the flanges via gaskets, the airtightness between the tubular sheet and the flanges is improved. In addition, the cylindrical sheet is not in direct contact with the metal so that it is not damaged or damaged.
[0030]
According to the metal expansion and contraction pipe joint of the invention according to claim 2, since the heat insulating material is interposed between the fluororesin cylindrical sheet and the metal sleeve, the temperature of the fluid flowing through the joint is considerably high. Even at high temperatures, it is possible to insulate with this heat insulating material to prevent the thermal effect on the cylindrical sheet and to extend the service life of the cylindrical sheet.
[Brief description of the drawings]
FIG. 1 is a half sectional view of a metal expansion joint according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a portion indicated by an arrow A in FIG.
FIG. 3 is a cross-sectional view of a metal expansion joint according to another embodiment of the present invention.
4 is an enlarged view of a portion indicated by an arrow B in FIG.
FIG. 5 is a cross-sectional view of a metal expansion joint according to still another embodiment.
[Explanation of symbols]
1A, 1B, 1C Metal expansion joint 2 Metal bellows 3 Flange for joining 4 Cylindrical sheet 5, 6 Metal sleeve 7, 8 Mounting flange K Thermal insulation 17 Gasket

Claims (2)

In a metal expansion and contraction pipe joint composed of a metal bellows and a joining flange attached to both ends of the metal bellows, a fluororesin cylindrical sheet covering the inner peripheral surface of the bellows is inserted into the bellows. each of both end portions of the cylindrical sheet, the flange being adapted to be attached via a gasket to, the further inner peripheral surface of the tubular sheet, a metal sleeve covering the cylindrical seat Different in diameter from each other, one of the sleeves is formed to have a length that is about the length of the metal bellows, and the other sleeve is formed to have a length that is about the length of the joining flange , A metal expansion / contraction pipe joint in which a pair of sleeves having a gap formed between the outer peripheral surface of the small diameter side sleeve and the inner peripheral surface of the large diameter side sleeve are provided in a nested manner.   The metal expansion joint according to claim 1, wherein a heat insulating material is interposed between the cylindrical sheet and the sleeve.

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