JPH11132863A - High-temperature gas piping - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict a temperature rise of a double tube because of heat conduction from a high-temperature fluid and at the same time prevent a damage because of vibrations, by arranging a projection to face to a temperature pocket at the inside of an area which is the inside of an outer tube of a protecting tube and the outside of an inner tube. SOLUTION: A thermometer pocket vibration isolation 14 of a cylindrical projection of a height L of approximately 20 mm is set at a position inside of protecting tubes 11, 12, 13 and outside of a liner 5 by approximately 60-150 mm. A shift of a thermometer pocket 10 because of vibrations of a high-temperature internal fluid 4 is supported by the vibration isolation 14. The thermometer pocket is reduced in amount of bend, and a stress brought about at a fixed part of the thermometer pocket 10 is decreased to not larger than a stress breaking the fixed part of the thermometer pocket 10. The vibration isolation 14 can support the thermometer pocket 10 on a plane and therefore, a stress concentration at a contact part when the vibration isolation 14 comes in touch or collides with the thermometer pocket 10 is prevented. Moreover, a temperature rise at a cap 8 and a pressure-resisting part of a washer 9 can be restricted when the protecting tubes 11, 12, 13 are enhanced in rigidity and the thermometer pocket 10 is reduced in sectional area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature pipe,
The present invention relates to a double pipe having a temperature measuring seat.

[0002]

2. Description of the Related Art Japanese Utility Model Application Laid-Open No. 4-1067334 discloses a thermocouple structure capable of measuring a fluid flowing in a pipe, by providing a sleeve between the thermocouple element and the thermocouple element to provide an end portion of the thermocouple element and the thermotube element. A device for preventing collision with the device is described.

Japanese Patent Application Laid-Open No. 7-174637 has a protective tube and a protective outer tube provided outside the protective tube. Insulating powder is inserted into the protective tube and between the protective tube and the protective outer tube. And the like are described.

[0004]

However, in the case of a pipe having a high-temperature fluid flowing therein, a double-pipe structure having an inner pipe through which the high-temperature fluid flows and an outer pipe outside the inner pipe via a heat insulating material is required. When a structure is adopted in which a thermometer is inserted into the inside through the outer tube and the inner tube, the shape becomes longer than that of a general single tube provided with a thermometer.

[0005] In a high-temperature pipe equipped with such a thermometer, the temperature measuring section receives a force from the fluid, so that vibrations and the like increase, and the possibility of damage increases. However, if the thermometer is made thicker to increase the rigidity, heat can easily be transmitted from the high-temperature fluid to the outside, and the outside such as the outer tube near the area where the thermometer is fixed may become hot.

[0006] In the cited example, there is no specific disclosure regarding the piping configuration in this regard.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a double pipe having a temperature measuring unit capable of preventing a temperature rise of an outer pipe of a double pipe due to heat conduction from a high-temperature fluid and preventing damage due to vibration. It is in.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a high-temperature gas pipe having an inner pipe through which a high-temperature fluid flows, and an outer pipe located on the outer peripheral side of the inner pipe via a heat insulating material. A thermometer seat provided at the base and a thermometer seat having a storage portion for fixing the thermometer seat portion, penetrating the outer tube and the inner tube, contacting the tip with a high-temperature fluid, and storing a thermocouple inside. A pocket, a protection tube fixed at the thermometer seat, located outside the temperature pocket, penetrating the outer tube, and arranged so that the tip is located outside the inner tube; and a protection tube of the outer tube. A projection disposed inside the region located outside the inner tube and facing the temperature pocket.

During operation of the plant, even when the load due to the internal high-temperature fluid applied to the thermometer pocket is large, or when the internal fluid and the thermometer pocket resonate,
The stress generated in the thermometer pocket fixing portion is equal to or less than the stress at which the thermometer pocket fixing portion is damaged, thereby improving the reliability of the high-temperature pipe.

Alternatively, an inner pipe through which a high-temperature fluid flows,
A high-temperature gas pipe having an outer pipe located on the outer peripheral side of the inner pipe via a heat insulating material, wherein a thermometer seat provided on the outer pipe is fixed with the thermometer seat, and the outer pipe is A temperature pocket provided with a storage part for penetrating the inner tube and contacting the high-temperature fluid at the tip and storing a thermocouple inside, and a thermometer seat fixed to the outside, located outside the temperature pocket, A protection tube that penetrates and is arranged so that the tip is located outside the inner tube;
A projection having a surface facing the temperature pocket, inside a region located inside the outer tube and outside the inner tube,
The surface facing the temperature pocket is formed to be smaller than the area of the fixed portion of the thermowell in the protection tube or the temperature pocket.

In addition, the amount of heat of the internal high-temperature fluid transmitted from the thermometer pocket to the outer pipe is reduced, the temperature of the outer pipe is kept below the design temperature, and the reliability of the high-temperature pipe is improved.

In addition to suppressing heat conduction from the high-temperature fluid and preventing damage due to vibration, even when the steady rest and the thermometer pocket are seized and fixed, the fixed portion is damaged, and the thermometer pocket fixing portion is protected to protect the thermometer pocket fixing portion. Piping reliability is improved.

Alternatively, an inner pipe through which a high-temperature fluid flows,
A high-temperature gas pipe having an outer pipe located on the outer peripheral side of the inner pipe via a heat insulating material, wherein a thermometer seat provided on the outer pipe is fixed with the thermometer seat, and the outer pipe is A temperature pocket provided with a storage part for penetrating the inner tube and contacting the high-temperature fluid at the tip and storing a thermocouple inside, and a thermometer seat fixed to the outside, located outside the temperature pocket, A protection tube that penetrates and is arranged so that the tip is located outside the inner tube;
A protrusion arranged inside the outer tube and inside the region located outside the inner tube so as to face the temperature pocket; and a protrusion arranged closer to the inner tube than the protrusion and having one end facing the high-temperature fluid and And a guide portion whose end is located inside the protection tube and in which the temperature pocket is located inside itself.

In addition to suppressing heat conduction from the high-temperature fluid to prevent damage due to vibration, it also prevents the internal fluid from entering the internal heat-insulating layer from the thermometer pocket insertion portion, and prevents the internal heat-insulating material from scattering. The internal high-temperature fluid is prevented from flowing from the vicinity of the thermometer pocket to the outer pipe side, and the reliability of the high-temperature pipe is improved.

Preferably, the projection has an annular protrusion from the inside of the protective tube, and the protrusion preferably has a semicircular cross section.

Preferably, the inner diameter of the protrusion is larger than the outer diameter of the thermometer pocket facing the protrusion.

Further, it is preferable that the projection has a plurality of projections formed at intervals in a circumferential direction inside the protection tube, and the projections preferably have a semicircular cross section.

As a result, the workability of the temperature measurement seat is improved, and the gap between the pocket through-holes of the liner is reduced to minimize the gas inflow. Alternatively, a pressurized fluidized bed including a compressor, a pressurized fluidized bed boiler to which compressed air discharged from the compressor is supplied, and a turbine to which exhaust gas discharged from the pressurized fluidized bed boiler is supplied and driven In the plant, the exhaust gas discharged from the pressurized fluidized bed boiler flows, an inner pipe through which the exhaust gas flows, and a double pipe having an outer pipe located on the outer peripheral side of the inner pipe via a heat insulating material, The double pipe is fixed with a thermometer seat provided on the exterior, and a thermometer seat, penetrates the outer tube and the inner tube, contacts the exhaust gas at its tip, and houses a thermocouple inside. A temperature pocket with a storage part and a protection tube fixed with a thermometer seat, located outside the temperature pocket, penetrating the outer tube, and arranged so that the tip is located outside the inner tube, and protection. Inside the region of the tube that is inside the outer tube and outside the inner tube It characterized by having a a projection which is arranged to face to degrees pocket.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. In FIG. 1, 1 is 20 in diameter.
An outer tube of about 00 mm, which is a pressure-resistant portion, and 2 and 3 provided inside the outer tube have a thickness of 2 including a castable heat insulating material 2 and a ceramic fiber heat insulating material 3.
It is an internal heat insulating material of about 50 mm, which makes it difficult for the heat of the high temperature internal fluid 4 of about 850 ° C. to be transmitted to the outer pipe 1.
The temperature is kept below the usable temperature. The inner pipe 5 is called a liner, and is a cylinder having a diameter of about 1500 mm provided to prevent the ceramic fiber-based internal heat insulating material 3 from scattering due to the flow of the high-temperature internal fluid 4. The liner 5 is supported by the outer tube 1 by a disk-shaped plate called a fixing rib 6. In the pipe having the above-described structure, a cylindrical seat 7 having a diameter of about 350 mm is provided such that the center thereof coincides with a position of about 250 mm in the longitudinal direction of the outer pipe 1 from the connection position of the outer pipe 1 and the fixing rib 6. And a cap 8 having a diameter of about 350 mm is provided at an end of the seat 7.
A seat 9 of about 0 mm is installed. Further, in order to insert a temperature sensing medium called a sheath (not shown), a rod-shaped thermometer pocket 10 having a diameter of about 35 mm and having a diameter of about 16 mm and having a diameter of about 16 mm is screwed to the seat 9 and fixed at one end. I have. The tip of the thermometer pocket 10 is inserted about 60 mm inward from the inner surface of the liner 5 and is in direct contact with the high-temperature internal fluid 4. During operation of the plant, a load is applied by the kinetic energy of the high-temperature internal fluid 4. ing. Further, the thermometer pocket 10 is made of a metal material, and has a higher thermal conductivity than the inner heat insulators 2 and 3. Because it tends to be higher than the tube temperature,
The heat capacity is increased by the thermometer seats such as the seat 7 and the cap 8, so that the outer tube temperature near the installation portion of the thermometer pocket 10 is suppressed to be low.

In the present embodiment, a pipe including a cylindrical protective pipe portion 11, 12, 13 having a diameter of about 60 mm is installed on the seat 9 by welding or cutting, and the protective pipe 1 is provided.
60 from the inside of 1, 12, 13 and outside of the liner 5
A thermometer pocket quiver 14 which is a cylindrical projection having a height L of about 20 mm is provided at a position of about 150 mm, and displacement of the thermometer pocket 10 due to the vibration of the high-temperature internal fluid 4 is changed by the quiver 14. To support. Thus, the amount of deflection was reduced, and the stress generated in the fixing portion of the thermometer pocket 10 was set to be equal to or less than the stress at which the fixing portion of the thermometer pocket 10 was damaged. In addition, since the main vibration stopper 14 can support the thermometer pocket 10 with a surface, it is possible to avoid stress concentration at a contact portion when the main vibration stopper 14 and the thermometer pocket 10 come into contact with or collide with each other. it can. The high-temperature internal fluid 4 is supplied to the outside of the thermometer pocket 10 and to the protective tube 1.
There is a possibility that the temperature of the outer pipe rises due to the flow in the pipe radial direction toward the outer pipe from the gaps on the inner side of the pipes 1, 12, and 13. can do. Further, the protective tubes 11, 12, 1
The rigidity 3 is increased by fixing with the castable heat insulating material 2.

The thermometer pocket 10 is in direct contact with the high-temperature internal fluid 4 while the protective tube 1
1, 12, 13 do not directly touch, so when the vibration stopper 14 and the thermometer pocket 10 are fixed,
The thermometer pocket 10 and the protective tubes 11, 12, 13
Since a large stress may be generated due to a difference in the thermal expansion amount of the thermometer, a gap of 0.5 mm or less may be secured between the inner side of the vibration stopper 14 and the outer diameter of the thermometer pocket. Reference numeral 10 denotes a structure that is not restricted by the thermal expansion to the protective tubes 11, 12, and 13. Even with such a structure having a gap, manufacturing errors,
Due to a construction error, displacement during operation, or the like, the outside of the thermometer pocket 10 and a part of the inside of the protective tube may come into contact with each other. When seizure occurs, the fixing points of the thermometer pocket 10 and the protective tubes 11, 12, and 13 are two places, so that a stress is generated in the fixing portion due to a temperature change due to a plant stop or a change in plant load, Either of the above two fixing points may be damaged. However, in the present invention, by setting the support width of the thermometer pocket (the height L of the steady rest) of the vibration stopper 14 to 60 mm or less to reduce the burning area, the burning area is reduced. Is damaged, and the screw portion, which is a pressure-resistant portion, is protected. In addition, since the liner 5 expands relatively in the radial direction due to thermal expansion, the lower ends of the protective tubes 11, 12, and 13 are separated from the liner 5 by two.
The hole for inserting the thermometer pocket 10 of the liner 5 and the thermometer pocket 1
Since the internal heat insulating material 3 may be scattered by the high temperature internal fluid 4 flowing from the gap 0, a guide having an outer diameter smaller than the inner diameter of the protection tube 11 and an inner diameter larger than the outer diameter of the thermometer pocket 10. 15 is provided on the liner 5 to prevent the high-temperature internal fluid 4 from directly contacting the internal heat insulator 3.

In these structures, the temperature of the high-temperature internal fluid 4 is mainly transmitted from the thermometer pocket 10 to the cap 8 and the seat 9, which are pressure-resistant parts, using the medium as a medium.
The smaller the cross-sectional area of the thermometer pocket 10, the more difficult it is to conduct heat. Therefore, by increasing the rigidity of the protection tubes 11, 12 and 13 that are not in direct contact with the high-temperature internal fluid 4 and reducing the cross-sectional area of the thermometer pocket 10, the temperature of the pressure-resistant portion of the cap 8 and the seat 9 is reduced. It is possible to suppress the rise.

FIG. 2 shows an example of the shape of the vibration stopper 14. The inner protrusion of the protection tube 11 has a cylindrical shape, and the corner of the surface facing the inner thermometer pocket is rounded. Thus, the thermometer pocket 10 can be easily inserted.

The thermometer pocket 10 and the vibration stopper 14
The larger the contact area is, the smaller the stress concentration at the contact portion on the left. On the other hand, from the standpoint of seizure of the contact portion and the standpoint of the amount of heat transfer from the thermometer pocket 10 to the protective tubes 11, 12, 13, it is advantageous to have a smaller contact area. Accordingly, when the rigidity of the thermometer pocket 10 is large with respect to the load caused by the high-temperature internal fluid 4, the thermometer pocket 10 is formed into a donut-shaped projection having a semicircular cross section as shown in FIG.
And the contact area can be reduced to reduce the burn-in area and the thermometer pocket 10.
The amount of heat transferred from the heat transfer pipe to the protection tubes 11, 12, 13 can be reduced, and the temperature of the cap 8 can be prevented from rising. With this structure, when the steady rest contacts the thermometer pocket,
There is no danger of one-sided contact, and it is possible to prevent local stress from being generated in the contact portion. The cross-sectional area need not be a true semicircle, but may be a substantially semicircle, and may be a semi-ellipse.

Further, as shown in FIG. 4, a steadying shape is provided at a plurality of hemispherical projections to support the thermometer pocket at points, so that the number of contact portions is further reduced to further reduce the image sticking area. Capable thermometer pocket 1
The amount of heat transfer from 0 to the protection tubes 11, 12, 13 is further reduced, and the temperature of the cap 8 can be prevented from rising.

Although the shape of the steady rest according to the present invention has been described with reference to FIGS. 1 to 5, the steady rest 14 may be installed on the thermometer pocket 10 side. In this case, since the thickness of the thermometer pocket 10 at the contact portion with the protective tube 12 is increased, the risk of the thermometer pocket 10 becoming thinner due to abrasion is reduced.

Further, for example, a ceramic fiber-based or castable-based heat insulating material 16 is provided above the vibration stopper 14 (on the outer tube side) and in the gap between the thermometer pocket 10 and the protective tubes 11 and 12. This makes it difficult to transmit the temperature of the high-temperature internal fluid 4 to the outer tube side, and has an effect of supporting the displacement of the thermometer pocket 10. Further, since a gap is formed below the vibration stopper 14, inside the protection tubes 12, 13 and outside the thermometer pocket 10, a ceramic fiber-based heat insulating material 17 is applied to reduce the temperature of the high-temperature internal fluid 4 to the outer tube. It has the effect of making it difficult to convey to the side.

As described above, according to the present embodiment, even when an excessive load is applied to the thermometer pocket due to internal fluid vibration and the thermometer pocket resonates, the amount of deflection of the thermometer pocket can be suppressed to a small value. The stress generated in the thermometer pocket fixing part can be reduced below the stress at which the thermometer pocket fixing part breaks, and the amount of heat transmitted from the internal high-temperature fluid temperature to the outer tube side is reduced, increasing the temperature of the outer tube temperature. Can be prevented.

Further, there is no possibility that the thermometer pocket is reduced in thickness due to abrasion with the protective tube.

Further, it is possible to prevent the internal fluid from entering through the gap of the thermometer pocket insertion portion of the liner and scattering the internal heat insulating material.

Hereinafter, the construction procedure of the present invention will be described. First, the seat 7 and the cap 8 are welded and connected to the outer tube 1 at the positions described in the section regarding the above-described structure, and the seat 7 and the left seat 7 are provided in order to prevent falling off when the castable heat insulating material 2 is applied later. A V-anchor 18 is welded and connected to the inside of the cap 8 at about three places around the circumference. Next, the seat 9 in which the vibration stopper 14 is integrated with the protection tube 11 not provided is placed on the cap 8.
And a V-anchor 19 is connected by welding to the outside of the protective tube 11 and at the same height as the V-anchor 18. At this time, the length of the protection tube 11 is set such that the lower end of the protection tube 11 is set at a position about 160 mm from the liner. Next, the castable heat insulating material 2 is applied to the inside of the seat 7 and the cap 8, the outside area of the protective tube 11 and the area of about 50 mm inside the outer tube, and dried. Next, a thermometer pocket 10 is inserted into the inside of the protection tube 11 from the side of the seat 9 and fixed to the seat 9 by screw connection, and a ceramic fiber-based heat insulating material is provided in a gap between the outside of the thermometer pocket 10 and the inside of the protection tube 11. 16 is constructed. Next, a protection tube 12 of about 60 mm having the vibration stopper 14 is inserted from the liner side, and is connected to the protection tube 11 by welding, or is subjected to thread cutting so that the protection tubes 11 and 12 can be screw-connected. The protection tube 13 is welded or screw-connected to the protection tube 12 in the same manner as described above, and the ceramic fiber-based heat insulating material 17 is installed in the gap between the protection tube 13 and the thermometer pocket 10 in the same manner as described above. I do. Next, a ceramic fiber heat insulating material 3 of about 200 mm is applied inside the castable heat insulating material 2 previously dried. Next, the liner 5 having a protrusion hole with a diameter of about 150 mm which is sufficiently large with respect to the thermometer pocket 10 is welded to the fixing rib 6. Finally, the closing plate 20 on which the guide 15 is installed
Is easily set and installed at a predetermined position, and is completed by closing the hole of the liner 5 at the penetrating portion of the thermometer pocket.

Thus, the workability of the temperature measuring seat can be improved, and the reliability of the high-temperature pipe can be improved.

FIG. 5 shows another embodiment.

This is a plant having a gas turbine and a pressurized fluidized bed boiler.

Specifically, a compressor 101 which takes in air, compresses and discharges the compressed air, a pressurized fluidized-bed boiler 103 to which compressed air discharged from the compressor 101 is supplied and fuel-bed and burns, The turbine includes a turbine 102 to which the combustion exhaust gas from the fluidized bed boiler 103 is supplied, an exhaust gas passage (not shown) through which the exhaust gas from the turbine 102 flows, and a generator 104 connected to a turbine shaft.

A pipe for guiding the combustion exhaust gas from the pressurized fluidized-bed boiler 103 to the turbine 102 is, for example, a double pipe having a temperature measuring unit as shown in FIG.

For example, 800-90 is used for the inner pipe of the double pipe.
Exhaust gas with a high temperature and high flow rate of 0 ° C. flows, but it is also possible to suppress damage due to vibration and the like even in the flow of the exhaust gas of such a high speed flow, and to suppress the heat of the exhaust gas from being transmitted to the outer tube and the outer tube being heated, It is possible to prevent dust or the like from entering the heat insulating section or the temperature measuring section.

The surface facing the temperature pocket is formed to be smaller than the area of the fixed portion of the thermometer seat of the protection tube or the temperature pocket, so that the temperature pocket is fixed between the temperature pocket and the projection facing the temperature pocket. However, even if there is a difference in thermal expansion between the two members, the temperature measurement seat can be prevented from being damaged, and leakage of the high-temperature fluid to the outside can be prevented.

Therefore, a highly reliable pressurized fluidized-bed boiler plant can be obtained, and a more reliable plant can be obtained by controlling the plant based on the temperature detected by the temperature measuring means.

[0040]

According to the present invention, it is possible to provide a double pipe provided with a temperature measuring section capable of preventing damage due to vibration while suppressing a rise in the temperature of the outer pipe of the double pipe due to heat conduction from a high-temperature fluid. it can.

[Brief description of the drawings]

FIG. 1 is a diagram of a seat structure for temperature measurement according to an embodiment of the present invention.

FIG. 2 is a view showing a steady rest shape according to an embodiment of the present invention.

FIG. 3 is a view showing a steady rest shape according to an embodiment of the present invention.

FIG. 4 is a diagram showing a steady rest shape according to an embodiment of the present invention.

FIG. 5 is a diagram showing one embodiment of the present invention.

[Explanation of symbols]

1 ... outer tube, 2 ... castable heat insulating material, 3, 16, 17
… Ceramic fiber insulation, 4… High temperature internal fluid, 5
... liner, 6 ... fixing rib, 7, 9 ... seat, 8 ... cap,
DESCRIPTION OF SYMBOLS 10 ... Thermometer pocket, 11, 12, 13 ... Thermometer pocket protection tube, 14 ... Thermometer pocket vibration stop, 15 ... Guide, 18, 19 ... V anchor for holding castable heat insulating material, 20 ... Closing plate, 101 ... Compressor, 102: Turbine, 103: Pressurized fluidized bed boiler, 104: Generator.

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

Claims (7)

[Claims] 1. A high-temperature gas pipe having an inner pipe through which a high-temperature fluid flows, and an outer pipe located on the outer peripheral side of the inner pipe via a heat insulating material, wherein a thermometer seat provided on the outer pipe. And a temperature pocket fixed with a thermometer seat, penetrating the outer tube and the inner tube, and having a tip for contacting a high-temperature fluid and having a housing for housing a thermocouple therein; and a thermometer seat. And a protection tube which is located outside the temperature pocket, penetrates the outer tube and is disposed so that the tip is located outside the inner tube; and a protection tube inside the outer tube and outside the inner tube. And a projection disposed inside the region located at a position facing the temperature pocket. 2. A high-temperature gas pipe having an inner pipe through which a high-temperature fluid flows, and an outer pipe located on the outer peripheral side of the inner pipe via a heat insulating material, wherein a thermometer seat provided on the outer pipe. And a temperature pocket fixed with a thermometer seat, penetrating the outer tube and the inner tube, and having a tip for contacting a high-temperature fluid and having a housing for housing a thermocouple therein; and a thermometer seat. And a protection tube which is located outside the temperature pocket, penetrates the outer tube and is disposed so that the tip is located outside the inner tube; and a protection tube inside the outer tube and outside the inner tube. A projection having a surface facing the temperature pocket, the surface facing the temperature pocket being formed to be smaller than the area of the fixed portion at the thermometer seat of the protection tube or the temperature pocket. Hot gas piping characterized by being made. 3. A high-temperature gas pipe having an inner pipe through which a high-temperature fluid flows, and an outer pipe located on the outer peripheral side of the inner pipe via a heat insulating material, wherein a thermometer seat provided on the outer pipe. And a temperature pocket fixed with a thermometer seat, penetrating the outer tube and the inner tube, and having a tip for contacting a high-temperature fluid and having a housing for housing a thermocouple therein; and a thermometer seat. And a protection tube which is located outside the temperature pocket, penetrates the outer tube and is disposed so that the tip is located outside the inner tube; and a protection tube inside the outer tube and outside the inner tube. A projection arranged inside the region located opposite to the temperature pocket, and arranged on the inner tube side with respect to the projection, one end facing the high-temperature fluid and the other end located inside the protection tube; A guide portion arranged such that a temperature pocket is located inside the inside of the housing. Scan piping. 4. The high-temperature gas pipe according to claim 1, wherein the projection has an annular projection from the inside of the protection tube, and the projection has a semicircular cross section. Hot gas piping. 5. The high-temperature gas pipe according to claim 4, wherein an inner diameter of the protrusion is larger than an outer diameter of a thermometer pocket facing the protrusion. 6. The high-temperature gas pipe according to claim 1, wherein the projection has a plurality of projections formed at intervals in a circumferential direction inside the protection tube, and the projections are semicircular. A high-temperature gas pipe having a cross section in a shape of a circle. 7. A compressor comprising: a compressor; a pressurized fluidized bed boiler to which compressed air discharged from the compressor is supplied; and a turbine to which exhaust gas discharged from the pressurized fluidized bed boiler is supplied and driven. In a pressurized fluidized bed plant, exhaust gas discharged from the pressurized fluidized bed boiler flows,
An inner pipe through which exhaust gas flows, and a double pipe having an outer pipe positioned on the outer peripheral side of the inner pipe via a heat insulating material, wherein the double pipe is a thermometer seat provided on the outer pipe. And fixed at the thermometer seat, penetrating the outer tube and inner tube, contacting the tip with exhaust gas, and having a storage compartment for storing a thermocouple inside, and fixed at the thermometer seat A protective tube that is located outside the temperature pocket, penetrates the outer tube, and is positioned so that the tip is located outside the inner tube; and a protective tube that is located inside the outer tube and outside the inner tube. Pressurized fluidized bed plant comprising: a projection disposed inside a region to be opposed to a temperature pocket.