JPH11153291A - Hot gas piping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly, sufficiently and closely attach a heat insulation material to an outer circumferential surface of a pipe by erecting a plurality of stud bolts on an inner wall of an outer pipe, and holding the heat insulation material against an inner wall surface of the outer pipe in a compressed manner by the stud bolts. SOLUTION: Because a fiber-like heat insulation material 4 is supported by stud bolts 6 installed on an outer pipe 2 or a fixed rib 11, the uneven distribution of the fiber-like heat insulation material 4 caused by the self weight thereof, the vibration of the piping, and the inflow of hot gas 1, can be prevented, and the thickness of the fiber-like heat insulation material 4 can be maintained constant. Degradation of the heat insulation effect caused by the change in thickness of the fiber-like heat insulation material 4 can be prevented, and the rated heat insulation performance can be obtained. The fiber-like heat insulation material 4 of each layer can be uniformly compressed by compressing the fiber-like heat insulation material 4 of each layer by a conical spring washer 7, a bolt 8 or a speed washer 22, the fiber-like heat insulation material 4 becomes dense by the compression, and the flow passage resistance of the gas can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a hot gas pipe for transferring a high temperature and high pressure gas from a boiler of a pressurized fluidized bed (PFBC) plant to a turbine, and more particularly to a double pipe having an inner pipe and an outer pipe. The present invention relates to a high-temperature gas pipe formed in a pipe and filled with a heat insulating material between the inner pipe and the outer pipe.

[0002]

2. Description of the Related Art A high-temperature gas pipe of this type, which has been generally employed, is composed of a pressure pipe (outer pipe) and a liner pipe (inner pipe) as disclosed in Japanese Patent Publication No. 61-19877. A plurality of (multi-layer) heat insulators whose outer diameter is formed in an annular shape in accordance with the inner diameter of the pressure pipe and whose inner diameter is matched with the outer diameter of the liner pipe; A pair of heat insulating material holding members for holding the material from its laminating direction, wherein the annular heat insulating material and the annular surface of the heat insulating material holding member are formed into a C-shaped cross section over the entire circumference, and the heat insulating material is tightened with the heat insulating material. The heat insulating material is tightened by bolts to expand the angle of the heat insulating material, and the heat insulating material is formed to be in close contact with the inner peripheral surface of the outer tube and the outer peripheral surface of the liner tube.

[0003]

The high-temperature equipment pipe or the high-temperature gas pipe formed as described above has a plurality of layers of heat-insulating material formed into a V-shape in cross section, which are clamped in the laminating direction by a pressing member to provide heat insulation. Since the square angle of the material is expanded, it seems that the heat insulating material adheres tightly to the inner peripheral surface of the outer tube and the outer peripheral surface of the liner tube. Although the heat insulating material is sufficiently compressed and the heat insulating material is sufficiently adhered, the tightening force of the heat insulating material pressing member is weak near the center between the pressing members, and the heat insulating material at the center does not adhere sufficiently, so that the bypass flow generated inside the heat insulating material is reduced. Due to the convection, the effective thermal conductivity of the heat insulating material increases, and a sufficient heat insulating effect cannot be obtained, and the leaked high-temperature fluid reaches the inner wall of the pressure pipe (outer pipe), which may adversely affect the pressure pipe.

Furthermore, when the high-temperature fluid is flowing through the inside of the tube, the heat insulating material adheres to the inner peripheral surface of the outer tube and the outer peripheral surface of the liner tube due to the radial thermal expansion of the liner tube. When the hot fluid is not flowing through the inside of the pipe, the liner pipe returns to its original diameter during cold time, and the compression recovery of the heat insulating material is poor. When a high-temperature fluid is allowed to flow, a bypass flow of the high-temperature fluid is generated in a gap formed between the inner surface of the outer tube and the outer surface of the liner and the heat insulating material, which may adversely affect the pressure piping.

Further, in this structure, the heat insulating material needs to be formed into a special shape, and the length of the tightening bolt needs to be equal to the interval between the heat insulating material holding plates. I hate it.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it easy to manufacture without using special molding and special parts, and to make a pipe irrespective of whether or not a high-temperature fluid flows inside the pipe. An object of the present invention is to provide a high-temperature gas pipe of this type in which a heat insulating material can be uniformly and sufficiently adhered to an outer peripheral surface.

[0007]

That is, the present invention relates to a high-temperature gas pipe formed in a double pipe comprising an inner pipe and an outer pipe and filled with a heat insulating material between the inner and outer pipes. A plurality of stud bolts are established on the inner wall surface of the pipe, and the stud bolt holds the heat insulating material on the inner wall surface of the outer pipe in a compressed state, thereby achieving an intended purpose.

The present invention also relates to a high-temperature gas pipe which is formed as a double pipe consisting of an inner pipe and an outer pipe and is filled with a heat insulating material between the inner and outer pipes. The heat insulating material is formed in a laminated body laminated in the radial direction of the pipe, and each layer of the laminated body is separated by the stud bolt and a speed washer fitted to the stud bolt. The inner wall of the tube is held in a compressed state.

In addition, the inner tube and the outer tube are formed as a double tube, a heat insulating material is filled between the inner and outer tubes, and the inner tube is supported by the outer tube via an annular rib, And, in a high-temperature gas pipe in which a slide gap for thermal expansion and contraction is provided at predetermined intervals in the longitudinal direction of the inner pipe, while establishing a plurality of stud bolts on the inner wall surface of the outer pipe and the side wall surface of the rib, Stud bolts established on the inner wall surface of the outer tube hold the heat insulating material in a compressed state on the inner wall surface of the outer tube, and stud bolts established on the rib side wall surfaces provide heat insulating material near the ribs. Are held in a compressed state on the side wall surface side of the rib, and the thermal expansion / contraction slide gap is formed near the rib.

In this case, the heat insulating material is formed of a laminate, and each layer of the laminate is compressed and held by a speed washer fitted to the stud bolt. Further, a guide member for guiding the gas leaked from the slide gap portion to the portion of the heat insulating material held in a compressed state on the inner wall surface of the outer tube is provided at the slide gap portion of the inner tube. .

That is, in the high temperature gas pipe formed as described above, the heat insulating material is held in a compressed state on the inner wall surface of the outer tube by a plurality of stud bolts established on the inner wall surface of the outer tube. The material is uniformly compressed throughout the axial and circumferential direction of the tube, even during hot time when hot gas is flowing inside the tube and during cold time when hot gas is not flowing inside the tube. In other words, even if thermal expansion and contraction occurs in the pipe, the heat insulating material is kept in close contact with the inner wall surface of the outer pipe.Therefore, without forming the heat insulating material into a special shape or using special parts, the high-temperature gas The heat insulating material can be uniformly and sufficiently adhered to the outer peripheral surface of the pipe regardless of the presence or absence of flow inside the pipe, thereby preventing the hot gas body flowing inside from reaching the outer pipe via the heat insulating material. It can be sufficiently prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 shows a cross section of the upper half of the hot gas pipe. Reference numeral 2 denotes an outer tube (for example, material: SCMV3, outer diameter: φ2450 mm, plate thickness: 25 mm) that holds an internal pressure, and 9 denotes an inner tube (for example, material: SUS).
310S, outer diameter φ1900mm, thickness: 6mm, length: 15
(00 mm), 4 is a heat insulating material filled between the outer tube 2 and the inner tube 9 and is a fiber-like material that suppresses heat conduction to the outer tube 2.

Inside the outer pipe 2, for example, high-temperature gas (pressure: about 0.88 MPa, temperature: about 870 ° C., flow rate: about 950 t / h) generated from a boiler of a pressurized fluidized bed combined cycle (PFBC) plant, for example. 1 is circulated, and a heat insulating material 3 such as a rock wool material that heats the outer tube 2 is provided outside the outer tube.
Is provided.

The inner pipe 9 serves to prevent the fibrous heat insulating material 4 from scattering, and is held inside the outer pipe 2 via fixing ribs 11 and annular fixing ribs 12. In addition,
The fixing rib 11 has its outer peripheral side fixed to the inner wall of the outer tube via a fixing rib mounting ring 10, the fixing rib 12 has its inner peripheral side fixed to the outer wall of the inner tube, and the fixing ribs are bolts 14 and nuts. 15.

On the inner wall surface of the outer tube 2, a plurality of stud bolt mounting seats 5 are provided scattered in the longitudinal direction and the circumferential direction of the tube. That is, for example, the stud bolt mounting seat has a pitch of 200 mm in the longitudinal direction of the pipe and a circumferential direction of 15 °.
It is fixed by welding to the inner wall of the outer tube at the pitch.

In the figure, reference numeral 17 denotes a gas inflow prevention plate for preventing high-temperature gas from flowing into the fibrous heat insulating material 4 side.
Reference numeral 18 denotes a seam of the fibrous heat insulating material 4, and reference numeral 19 denotes a thermal expansion / contraction slide gap for absorbing thermal expansion of the inner tube 2 in the axial direction.

A stud bolt 6 is mounted on the stud bolt mounting seat, and four layers of fibrous heat insulating material 4 having a thickness of, for example, 50 mm, and a thickness of 75 mm are provided from the outer tube 2 side.
One layer of the fiber-shaped heat insulating material 4 is compressed by about 25% and attached to the outer pipe via a stud bolt. At this time, the first to fourth layers are compressed and attached to the stud bolts 6 by the speed washers 22 for each layer, and the fifth layer, which is the outermost layer (the lowermost layer in the figure), is connected to the nut 8 via the dishwasher 7 and the nut 8. Attach it to the bolt 6 by compressing it. When the fiber-like heat insulating materials 4 are applied, they are alternately applied so that the joints 18 of the heat insulating materials are not aligned in the radial direction.

On the other hand, a gap ring 13 is welded to the outer circumference of one end of the inner pipe 2, and a cylindrical inner pipe support ring for suppressing a radial displacement of the inner pipe is further provided on the outer circumference thereof. One end of 16 is welded. The inner peripheral end of the fixing rib 12 is welded to the outer periphery of the inner pipe support ring 16. Further, the stud bolt mounting seats 5 are welded to the fixing ribs 12 at a pitch of 10 ° in the circumferential direction, and the stud bolts 6 are mounted. At this time, the stud bolt 6 is mounted so that the mounting direction is on the upstream side of the flow of the high-temperature gas 1.

From the inner peripheral end of the fixing rib 11, 30
At the position of mm, bolt holes for passing the bolts 14 at 90 ° intervals in the circumferential direction are provided in advance. Then, the bolt 14 is passed through the bolt hole and welded to the fixing rib 11. On the other hand, in order to pass the bolt 14 at a position of 30 mm in the radial direction from the outer peripheral end of the fixing rib 12 at 90 ° intervals in the circumferential direction,
From the position 30mm radially from the outer edge,
A slot formed by sliding by 0 mm is provided in advance. Then, the washer 23 is passed through the threaded portion of the bolt 14, the elongate hole of the fixing rib 12 is passed, and the fixing ribs 11, 12 are fastened with the nut 15 to the extent that the sliding of the fixing ribs 12 is not hindered. I do. At this time, nut 1
A non-rotating weld is applied to the nut portion to prevent the 5 from coming off.

Outer tube 2 to which fiber-like heat insulating material 4 is attached
And one piece inner tube 9 (length 1500mm) with fixing rib 1
After fixing at 1 and 12, the fibrous heat insulating material (for example, thickness 5
0 mm) 4 in 3 layers, about 25% parallel to the fixing ribs 11 and 12
The work is compressed and fixed with bolts 8 via dish washers 7. At this time, the first and second layers are compressed and attached to the stud bolt 6 by the speed washer 22 for each layer, and the third layer, which is the outermost layer, is compressed and attached to the stud bolt 6 by the nut 8 via the dishwasher 7.

After the fibrous heat insulating material 4 is further applied to the inner surface of the outer tube 2 from the fixing ribs 11 and 12 to 1500 mm upstream, the end of the gas inflow prevention plate 17 is welded to the end of the inner tube support ring 16. . At this time, care should be taken so that the heat insulating material joint 18 is not located at the end of the gas inflow prevention plate 17.

The above operation is performed for each piece from the downstream side with respect to the flow of the high-temperature gas 1 to produce a high-temperature gas pipe.

According to this embodiment, the fibrous heat insulating material 4 is supported by the stud bolts 6 installed on the outer tube 2 or the fixing rib 11, so that the own weight of the fibrous heat insulating material 4, vibration of the pipe, and The uneven distribution due to the inflow of the high-temperature gas 1 can be prevented, and the thickness of the fibrous heat insulating material 4 can be kept constant. Thereby, a decrease in the heat insulating effect due to a change in the thickness of the fibrous heat insulating material 4 can be prevented, and a rated heat insulating performance can be obtained.

By compressing the fibrous heat insulating material 4 of each layer with the dish washer 7 and the bolt 8 or the speed washer 22, the fibrous heat insulating material 4 of each layer can be uniformly compressed. Since the material 4 becomes dense, the gas flow path resistance can be increased. Thereby, the inflowing high-temperature gas 24 can be prevented from reaching the outer tube 2 via the fiber-shaped heat insulating material 4, and gas leak from the outer tube 2 and generation of a heat spot (local high-temperature portion) can be prevented.

By installing stud bolts 6 for supporting the fibrous heat insulating material 4 on the outer tube 2 or the fixing rib 11, the fibrous heat insulating material 4 of the manufacturer's rated size can be used. 18
Can be constructed so as not to be aligned in the radial direction. Similarly, it is not necessary to use a special stud bolt 6 and a stud bolt 6 having a maker rated size can be used.

Since the fibrous heat insulating material 4 is supported by the stud bolts 6 from the outer pipe 2, the inner circumferential surface of the outer pipe 2 and the fibrous heat insulating material 4 are always maintained regardless of the start / stop of the plant.
And can be in close contact. Thereby, the inflowing high-temperature gas 24 can be prevented from flowing through the gap between the inner peripheral surface of the outer tube 2 and the fibrous heat insulating material 4, and gas leak from the outer tube 2 and generation of a heat spot can be prevented.

By providing the gas inflow prevention plate 17 at the connection portion (the heat-expandable slide gap 19) between the divided inner tubes, the gas flow resistance increases. This allows
The hot gas 1 can be prevented from flowing into the internal heat insulating material. Even if the high-temperature gas 1 flows in, the flow velocity of the internally flowing high-temperature gas 24 can be reduced. Thereby, it is possible to prevent the internal inflow high-temperature gas 24 from reaching the outer pipe 2 via the fibrous heat insulating material 4 or the heat insulating material seam 18,
Gas leaks from the outer tube 2 and generation of heat spots can be prevented.

FIGS. 7 and 8 are schematic diagrams showing the flow of the high-temperature gas in the heat insulating material when the high-temperature gas flows. FIG. 7 shows a case where the internal heat insulating material is not compressed, and FIG. 8 shows a case where the internal heat insulating material is compressed. As can be seen from FIG. 7, when the internal heat insulating material is not compressed, the internal inflowing high-temperature gas 24 flowing from the thermal expansion / contraction slide gap 19 easily flows along the heat insulating material seam 18, and the natural convection and heat flows in the internal heat insulating material. A bypass flow 25 is created.

On the other hand, as can be understood from FIG. 8, when the internal heat insulating material is compressed, the heat flowing into the internal high temperature gas 24 cannot easily flow because the heat insulating material seam 18 is in pressure contact. Further, the compression of the fibrous heat insulating material 4 and the increase of the flow path resistance do not cause the natural convection / bypass flow 25.

FIGS. 3, 4, 6 and 9 show a second embodiment of the high-temperature gas pipe according to the present invention. FIG. 3 corresponds to FIG. 1 of the first embodiment. FIG. 4 corresponds to FIG. 2 of the first embodiment, and FIG. 6 corresponds to FIG. 5 of the first embodiment. FIG. 9 is a diagram showing how to attach a chain link. In the figure, reference numeral 20 denotes a chain link for preventing the concrete heat insulating material 21 from falling off, and reference numeral 21 denotes a concrete heat insulating material for protecting the outer pipe 2.

As in the previous embodiment, the inner circumference of the outer tube 2
The fixed rib mounting ring 10 is welded, and further on its inner periphery,
The outer peripheral end of the fixing rib 11 is welded. A stud bolt mounting seat 5 having a length of 50 mm is provided on the inner periphery of the outer pipe 2 in the axial direction 200.
At a pitch of 15 mm in the circumferential direction, the chain link 20 is spot-welded to the center between the stud bolt mounting seats 5 as shown in FIG.

Further, a 50 mm-thick concrete heat insulating material 21 is applied to the inner surface of the outer tube 2 by ironing, dried and cured. Then, the stud bolt 6 is attached to the stud bolt mounting seat 5, and the thickness is 50 mm from the outer pipe 2 side.
3 layers of fibrous heat insulating material 4 and one layer of 75 mm thick fibrous heat insulating material 4 are compressed by about 25% and attached to the outer tube. At this time, the first to third layers are compressed and attached to the stud bolts 6 by the speed washers 22 for each layer, and the fourth layer, which is the outermost layer, is compressed to the stud bolts 6 by the nut 8 via the dishwasher 7. Attach.

When the fiber-shaped heat insulating material 4 is applied, the seams 18 of the heat insulating material are not aligned in the radial direction.
Work alternately.

On the other hand, a gap ring 13 is welded to the outer circumference of one end of the inner pipe 2 and further
One end of the inner pipe support ring 16 is welded. And
The inner peripheral end of the fixing rib 12 is welded to the outer periphery of the inner pipe support ring 16. Also, the stud bolt mounting seats 5 are welded to the fixing ribs 12 at a pitch of 10 ° in the circumferential direction, and the stud bolts 6 are mounted. At this time, the stud bolt 6 is mounted on the upstream side of the flow of the high-temperature gas 1.

The radial direction of the fixing rib 11 is 30
At the position of mm, bolt holes for passing the bolts 14 at 90 ° intervals in the circumferential direction are provided in advance. A bolt 14 is passed through the bolt hole and welded to the fixing rib 11. On the other hand, in order to pass the bolt 14 at a position of 30 mm in the radial direction from the outer peripheral end of the fixing rib 12 at 90 ° intervals in the circumferential direction, slide the inner rib 20 mm in the radial direction from the position of 30 mm in the radial direction from the outer peripheral end. Is provided in advance.

Then, the washer 23 is passed through the screw portion of the bolt 14, and the fixing rib 1 is passed through the elongated hole of the fixing rib 12.
The fixing rib 11 and the fixing rib 12 are fixed to each other by tightening the nut 15 so as not to hinder the sliding of the fixing ribs 1 and 12.
At this time, rotation prevention welding is performed to prevent the nut 15 from coming off.

The outer tube 2 to which the fiber heat insulating material 4 and the concrete heat insulating material 21 are attached and the one-piece inner tube 9 (length: 1500 mm) are fixed by the fixing ribs 11 and 12, and then the thickness is 5 mm.
Three layers of 0 mm fiber heat insulating material 4, fixing ribs 11, 1
The work is compressed by about 25% in parallel with 2 and fixed with bolts 8 via dish washers 7. At this time, the first and second layers are compressed and attached to the stud bolt 6 by the speed washer 22 for each layer, and the third layer, which is the outermost layer, is compressed and attached to the stud bolt 6 by the nut 8 via the dishwasher 7.

Further, after the fiber-like heat insulating material 4 and the concrete heat insulating material 21 are further applied to the inner surface of the outer tube 2 from the fixing ribs 11 and 12 to 1500 mm upstream, the gas inflow prevention plate 17 is attached to the end of the inner tube support ring 16. Weld the ends. At this time, care should be taken so that the heat insulating material joint 18 is not located at the end of the gas inflow prevention plate 17.

The above operation is performed for each piece from the downstream side with respect to the flow of the high-temperature gas 1 to produce a high-temperature gas pipe.

According to this embodiment, the following effects can be obtained in addition to the effects obtained by the first embodiment. That is, the concrete-like heat insulating material 2
1 is applied to the inner peripheral surface of the outer tube 2 so that even if the inflowing high-temperature gas 24 flowing from the thermal expansion / contraction slide gap 19 reaches the outer tube 2 via the fiber-shaped heat insulating material 4, the outer tube 2 , And the occurrence of heat spots on the outer tube 2 and the leakage of the hot gas 24 flowing into the inside can be prevented.

As described above, with the high temperature gas pipe heat insulating material structure formed as described above, the packing density of the heat insulating material is made uniform, and the heat insulating material is closely attached to the inner peripheral surface of the outer tube and the outer peripheral surface of the liner. Thereby, the convection and bypass flow of the high-temperature gas inside the heat insulating material can be prevented, so that a uniform effective thermal conductivity of the heat insulating material can be secured, and a rated heat insulating effect can be obtained.

Further, since the gap between the inner peripheral surface of the outer tube and the heat insulating material, which is caused by the repetition of the inflow of the high temperature fluid, can be eliminated, it is possible to prevent the high temperature gas from flowing into the gap between the inner peripheral surface of the outer tube and the heat insulating material. In addition, abnormal rise of the outer tube temperature and leakage of high-temperature gas can be prevented.

Further, since the joints of the heat insulating material can be constructed so as not to be aligned in the radial direction, high-temperature gas is prevented from flowing along the seam of the heat insulating material and reaching the outer pipe,
It is possible to sufficiently prevent abnormal rise in the outer tube temperature and leakage of high-temperature gas. In addition, since a bolt or a heat insulating material having a rated size can be used, it is not necessary to use a special bolt or a heat insulating material, and the cost can be reduced.

[0044]

As described above, according to the present invention, it is possible to easily manufacture without using special molding or special parts, and to insulate the outer peripheral surface of the pipe irrespective of whether or not the high-temperature fluid flows inside the pipe. This type of high-temperature gas pipe can be obtained in which materials can be uniformly and sufficiently adhered.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view showing a main part of an embodiment of a high-temperature gas pipe according to the present invention.

FIG. 2 is a quarter sectional view taken along the line AA of FIG.

FIG. 3 is a vertical sectional side view showing a main part of another embodiment of the high-temperature gas pipe of the present invention.

FIG. 4 is a quarter sectional view taken along the line CC of FIG. 3;

FIG. 5 is an enlarged cross-sectional view of a frame B of FIG. 1;

FIG. 6 is an enlarged sectional view of a D-frame portion in FIG.

FIG. 7 is a schematic diagram of a flow of a high-temperature gas in a heat insulating material when a high-temperature gas flows in (when an internal heat insulating material is not compressed).

FIG. 8 is a schematic diagram of a flow of a high-temperature gas in a heat insulating material when a high-temperature gas flows in (when an internal heat insulating material is compressed and filled).

FIG. 9 is a plan view showing how to attach a chain link.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... High temperature gas, 2 ... Outer tube, 3 ... Heat insulator, 4 ... Fibrous heat insulating material, 5 ... Stud bolt mounting seat, 6 ... Stud bolt, 7 ... Dish washer, 8 ... Nut, 9 ... Inner tube, 10 ...
Fixed rib mounting ring, 11: outer tube side fixed rib, 12: inner tube side fixed rib, 13: gap ring, 14: bolt,
Reference numeral 15: Nut, 16: Inner pipe support ring, 17: Gas inflow prevention plate, 18: Thermal insulation joint, 19: Thermal expansion / contraction slide gap, 20: Chain link, 21: Concrete-like thermal insulation, 22: Speed washer, 23 ... Washer, 24: High temperature gas flowing into the inside, 25: Natural convection / bypass flow.

Continued on the front page (72) Inventor: Yu Shida 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant (72) Inventor: Tokuyuki Ichinose 2-6-1, Otemachi, Chiyoda-ku, Tokyo Babcock Hitachi, Ltd.

Claims (5)

[Claims] 1. A high-temperature gas pipe formed into a double pipe comprising an inner pipe and an outer pipe and filled with a heat insulating material between the inner and outer pipes, wherein a plurality of stud bolts are provided on an inner wall surface of the outer pipe. And the stud bolts hold the heat insulating material on the inner wall surface of the outer tube in a compressed state. 2. A high-temperature gas pipe formed into a double pipe consisting of an inner pipe and an outer pipe and filled with a heat insulating material between the inner and outer pipes, wherein a plurality of stud bolts are provided on an inner wall surface of the outer pipe. And the heat insulating material is formed in a laminated body laminated in the radial direction of the pipe, and each layer of the laminated body is formed inside the outer pipe by the stud bolt and a speed washer fitted to the stud bolt, respectively. A high-temperature gas pipe characterized by being held in a compressed state on a wall surface side. 3. An inner tube and an outer tube are formed as a double tube, a heat insulating material is filled between the inner tube and the outer tube, and the inner tube is supported by the outer tube via an annular rib, And in a high-temperature gas pipe in which slide gaps for thermal expansion and contraction are provided at predetermined intervals in the longitudinal direction of the inner pipe, while establishing a plurality of stud bolts on the inner wall surface of the outer pipe and the side wall surface of the rib, Stud bolts established on the inner wall surface of the outer tube hold the heat insulating material in a compressed state on the inner wall surface of the outer tube, and stud bolts established on the rib side wall surfaces provide heat insulating material near the ribs. A high-temperature gas pipe characterized in that the heat-expandable slide gap is formed in the vicinity of the rib. 4. The heat insulating material according to claim 3, wherein the heat insulating material is formed of a laminate, and each layer of the laminate is compressed and held by a speed washer fitted to the stud bolt. Hot gas piping. 5. A guide member for guiding a gas leaked from the slide gap portion to a portion of a heat insulating material held in a compressed state on the inner wall surface of the outer tube is provided in the slide gap portion of the inner tube. The high-temperature gas pipe according to 3 or 4.