JPS62155395A - Structure connecting tube and tube plate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a connection structure between a tube and a tube sheet that is applied to a heat exchanger, a filter device, etc. using ceramic tubes.

"Prior Art and its Problems" Conventionally, in heat exchangers using metal tubes, the tubes have been attached by welding directly to the tube plate or by expanding the tubes. Therefore, the airtightness between the heating fluid and the heated fluid was sufficiently maintained. However, 800
It is difficult to exchange heat with high-temperature fluids above ℃ using metal tubes. In such cases, ceramic tubes are used, but needless to say, in this case, connection by welding or tube expansion is not possible. Furthermore, when connecting ceramic tubes, it is necessary to have a structure that absorbs the difference in thermal expansion and mechanical shock that occurs between the ceramic tube and the metal tube plate or can body.

Based on the above request, the applicant has already filed a patent application in
No. 782 proposes a connection structure between ceramic tubes and tube sheets that absorbs the thermal expansion difference and mechanical shock that occur between the ceramic tubes and the tube sheets, and also ensures sufficient sealing performance. . However, in this connection structure, an organic rubber-based buffer layer is poured and formed between the inorganic heat insulating layer provided on the outer periphery of the connection part of the ceramic pipe and the water-cooled wall of the tube sheet of the water-cooled structure. Because the ceramic tube is inserted and held through the holding hole in the tube sheet, it requires a large amount of man-hours to inject or remove the organic rubber buffer layer when attaching or removing the ceramic tube to the tube sheet. This has hindered the ability to increase the size of the device.

``Object of the Invention'' The purpose of the present invention is to solve the problems of the prior art described above, to make the connection between the ceramic tube and the tube sheet easier, and to connect the tube and the tube sheet with sufficient sealing performance. The goal is to provide a structure that connects the

"Summary of the Invention" According to the structure for connecting a tube and a tube sheet according to the present invention, an inorganic heat insulating layer surrounds the outer periphery of the connection part of the ceramic tube, and a polymeric buffer layer surrounds the outer periphery of the inorganic heat insulating layer. box,
Furthermore, a metal holder surrounds the outer periphery of this buffer layer to integrate the ceramic tube and the metal holder, and the ceramic tube is held on the tube plate by the metal holder.

Therefore, the ceramic tube can be connected to the tube sheet simply by placing or connecting the connection part of the metal holder on the tube sheet, making it extremely easy to attach and detach the ceramic tube to the tube sheet, eliminating the need for complicated on-site construction. The number of man-hours can be significantly reduced, and the fluid can be sufficiently sealed.

To explain the present invention in more detail, the inorganic heat insulating layer is formed, for example, in a cylindrical shape, using ceramics of the same quality as the tube, castable refractories, mortar, etc., so as to surround the ceramic tube.

In this case, the heat insulating layer is preferably made of a material that does not cause a difference in thermal expansion from the ceramic tube.

In a more preferred embodiment, the heat insulating layer is composed of an inner layer made of ceramic fiber, paper, woven fabric, etc., and an outer layer made of castable refractory material. If the heat insulating layer is composed only of layers such as castable refractories, the thermal expansion of the heat insulating layer will not follow the thermal expansion of the ceramic tube during transient conditions such as during startup, and compressive stress will be applied to the ceramic tube from the surroundings. This may cause cracking, or conversely, a gap may form between the ceramic tube and the heat insulating layer, resulting in poor sealing performance. However, by making this heat insulating layer have a dual structure of an inner layer and an outer layer, such concerns can be avoided due to the cushioning properties and heat resistance of the inner layer.

As a polymer-based buffer layer, for example, silicone rubber-based or fluororubber-based ones are heat resistant, highly elastic, or
It is preferably used from the viewpoint of resistance to corrosive components in high-temperature gas. The buffer layer is preferably formed by injecting an organic rubber-based substance as described above between the inorganic heat insulating layer and the metal wall constituting the metal holder, or by injecting it into the outer periphery of the heat insulating layer or the inner periphery of the metal wall of the metal holder. By applying the metal holder in advance, it is formed so as to fill the gap between the heat insulating layer and the metal holder and seal it. In addition, as a polymer cushioning material,
Inorganic polymers made of enamel also have elasticity and are more preferably used from the viewpoint of heat resistance and corrosion resistance.

As yet another method of forming the buffer layer, a cylindrical molded organic rubber product or a cylindrical-shaped organic rubber plate may be inserted into the gap between the heat insulating layer and the metal holder. Furthermore, it is also effective to have a part or all of the surface fixed by a method such as adhesion or sealing with an amorphous organic rubber.

It is desirable that the inorganic heat insulating layer lowers the temperature at which the organic rubber of the buffer layer can maintain its elasticity to, for example, 200 to 250 degrees Celsius, but it is more preferable to use the buffer layer with a low-temperature fluid such as water. It is preferable to have a structure in which cooling is performed indirectly. Specifically, the tube sheet is provided with a cooling structure so that the metal holder is radiantly cooled by the cooling wall of the tube sheet, which has a low temperature. As a result, the cooled metal holder insulates the polymer-based buffer layer, so that the buffer layer is cooled down to a level where it can maintain its elasticity by both the metal holder and the aluminous insulation layer. Alternatively, it absorbs the difference in thermal expansion and mechanical shock that occurs between it and the can.

The connection structure of the present invention can be applied, for example, to the connection between a ceramic heat transfer tube and a tube sheet in a heat exchanger, as well as the connection between a ceramic filter tube and a tube sheet in a dust removal device from high-temperature gas. .

"Embodiment of the Invention": Fig. jrJ1 shows an embodiment in which the connection structure according to the present invention is applied to the lower end portion of the ceramic tube 11. When applying this connection structure to a heat exchanger,
For example, high-temperature heating gas is flowed into the inner space 3B of the ceramic tube 11, and low-temperature heated gas is flowed into the outer space 37. This may be reversed, and when applied to a dust removal device, high-temperature dust-containing gas is flowed into the internal space 36 of the ceramic tube 11 having a filter function, and the clean gas that has passed through the ceramic tube 11 is is the external space 37
waves.

The opposite may be true.

The metal tube plate 12 has a cooling structure in which a cooling chamber 13 is formed, and the lower end connection part of the ceramic tube 11 is connected to a cooling wall 14.
It is inserted into and held in a holding hole 15 formed by. A woven ceramic cloth 18 is wrapped around the outer periphery of the lower end of the ceramic tube 11, and a castable refractory layer 17 as a heat insulating material is further arranged around the outer periphery of the woven ceramic cloth 16. A metal holder 18 is further arranged on the outer periphery of the castable refractory layer 17 with a predetermined gap maintained therebetween.

The metal holder 18 has an outer circumferential flange 18 formed toward the outer circumferential direction at the upper end, and an inner circumferential flange 20 formed toward the inner circumferential direction at the lower end. The lower surfaces of the ceramic tube 11 and the castable refractory layer 17 are in contact with the upper surface of the inner peripheral flange 20.
A buffer layer 21 formed by pouring silicone rubber or the like is formed in the gap created between the metal holder 7 and the metal holder 18 . Then, the ceramic tube 11 is attached to the metal holder 1 via the buffer layer 21 and the castable refractory layer 17.
It is integrated with B. In this embodiment, the buffer layer 21 has a thickness of about 0.5 to 3 mm.

Further, an annular projection 22 is provided on the lower surface of the outer edge of the outer peripheral flange 18.
is formed and comes into contact with a packing 23 provided near the holding hole 15 on the top surface of the tube plate 12. Therefore, the ceramic tube 11 is inserted into the annular projection 2 through the metal holder 1B.
2 is held in contact with and placed on the gasket 23 on the upper surface of the tube plate 12.

In this case, the seal between the annular protrusion 22 and the upper surface of the tube plate 12 is performed by the packing 23, but in order to increase the sealing surface pressure, the contact width of the annular protrusion 22 with respect to the packing 23 is machined into a knife shape to reduce it. It is. Note that it is of course possible to secure the sealing surface pressure by tightening the bolts, although the number of man-hours increases slightly.

The lower end of the ceramic tube 11 as described above is attached to the tube plate 12.
To insert and hold the ceramic tube 1 through the holding hole 15 of
It is only necessary to place the annular protrusion 22 of the metal holder 18 that is integrated with the metal holder 1 on the packing 23 on the upper surface of the tube plate 12. As a result, the weight of the ceramic tube 11 etc. is applied to the packing 23. Top surface of tube plate 12 and annular projection 22
The space between the two is airtightly sealed with a gasket 23 to prevent fluid leakage.

Therefore, according to this connection structure, the ceramic tube 11 can be attached and detached from the tube plate 12 very easily, and the time required for one assembly and open inspection can be significantly shortened.

In this connection structure, assuming that the temperature of the gas passing through the ceramic tube 11 is 700° C., the castable refractory layer 17 acts as a heat insulating layer, and the metal holder 1B is radiantly cooled by the cooling wall 14. Therefore, the buffer layer 21 is kept cool at about 180°C to maintain its buffering force, and the ceramic tube 11 is kept cool due to thermal expansion differences and mechanical shocks.
and the tube sheet 12. Furthermore, in a transient state such as during startup, the thermal expansion of the castable refractory layer 17 does not follow the thermal expansion of the ceramic tube 11, and stress is generated between the ceramic tube 11 and the castable refractory layer 17. However, this stress will be absorbed by the ceramic woven fabric 16.

FIG. 2 shows another embodiment in which the connection structure according to the present invention is applied to the upper end portion of the ceramic tube 11. Note that parts having the same polarity as those in FIG. 1 are given the same reference numerals, and a description thereof will be omitted. A woven ceramic cloth 16 is wound around the outer periphery of the upper end of the ceramic tube 11, and a castable refractory layer 17 held by a metal holder 18 is disposed outside the woven ceramic cloth 16. In the gap between the outer periphery of the castable refractory layer 17 and the inner periphery of the metal holder 18, a cylindrical buffer layer 21 made of silicone rubber or the like and having a thickness of about 0.5 to 3 cm is arranged. The ceramic tube 11 is integrated with the metal holder 18 via the buffer layer 21 and the castable refractory layer 17.

The integration of the ceramic tube 11 and the metal holder 18 is as follows:
For example, it is done as follows. A plate-shaped temporary frame (not shown) is placed on the outside of the ceramic tube 11 that has been wrapped with a ceramic woven cloth 16 in advance, and a metal holder 18 is coated with a thick paste such as silicone rubber on the inside.
Place it on the plate-like temporary frame. A slurry of castable refractory is poured onto the temporary frame in the gap between the metal holder 18 and the ceramic tube 11, and after this slurry is allowed to harden, the temporary frame is removed. At this time, the main parts of the castable refractory layer are removed. Using a preformed product, the castable refractory slurry may be poured or press-fitted only in the part that contacts the ceramic woven fabric 16 or further in the part that contacts the buffer layer 21. If this slurry penetrates too much,
It is preferable to interpose a resin film around the outer periphery of the ceramic woven fabric 16.

(If the inner peripheral flange 20 is provided as shown in FIG. 1, the temporary frame described above is not necessary.) The metal holder 18 has a mounting flange 24 facing outward at its upper end. On the mounting flange 24, the bellows ring 2B is tightened and fixed by a port 27 via a packing 25. One end of the bellows 2 is attached to the outer end of the bellows ring 26. Also,
A bellows ring 30 is fastened to the vicinity of the holding hole 15 on the upper surface of the tube plate 12 via a packing 29 by a pin 31, and the other end of the bellows 28 is attached to the inner end of the bellows ring 30. installed. In this embodiment, the bellows 28 allows relative displacement between the tube sheet 12 and the ceramic tube 11 while ensuring a fluid seal. Metal holder 18 and castable refractory layer 17
Insulating materials 32 and 33 are placed on the lower surface of the housing 32 and 33 by pasting or hanging them. Further, 34 is a heat insulating material having a ferrule shape, and the ceramic tube 11 is connected to the tube sheet 1.
Placed after connecting to 2.

To connect the ceramic tube 11 to the tube plate 12, the ceramic tube 11 is inserted into the holding hole 15, and a mounting structure provided at the lower part of the ceramic tube 11, which is not shown in FIG. Next, place the packing 2 on the mounting flange 24 (not shown).
5, the bellows ring 26 is tightened and fixed by a port 27, and the bellows ring 3° is also tightened and fixed by a port 31 on the tube plate 12 via a packing 29. Thereby, the ceramic tube 11 is connected through the holding hole 15 of the tube plate 12, and the bellows 28 reliably seals the fluid. In this case, if either the bellows ring 26 or the bellows ring 30 is fixed in advance, the connection work will be made easier.

In this connection structure, the length of the ceramic tube 11 is set to 211, and high temperature gas at 700° C. is introduced from the top of the ceramic tube 11. In that case, only the ceramic tube 11 becomes high temperature at the start of the inflow, the ceramic tube 11 extends upward by about 1.5 mm, and the temperature of the can body steel rises to about 70"C in about an hour after the inflow. The expansion will catch up with the elongation of the ceramic tube 11, but the difference in thermal expansion in the axial and radial directions during this time will be absorbed by the ceramic woven fabric 16 and the a+ layer 21, preventing the ceramic tube 11 from being damaged. Prevented.

Note that, for example, the lower outer circumference of the buffer layer 21 is bonded to the inner circumference of the metal holder 18, and the upper inner circumference thereof is bonded and held to the outer circumference of the castable refractory layer 17, or crimped and held using rubber elasticity. If the vertical center of the buffer layer 21 is not bonded to either the castable refractory layer 17 or the metal holder 18, the ceramic tube 11 will undergo a larger relative displacement in the axial direction with respect to the metal holder 18. It is also possible to absorb this.

"Effects of the Invention" As explained above, according to the present invention, the inorganic heat insulating layer and the radiation-cooled metal holder keep the buffer layer cool enough to maintain its elasticity. In addition, the buffer layer absorbs thermal expansion differences and mechanical shocks. In addition, when connecting the tube and tube sheet via a metal holder, the connection part is equipped with a combination of a gasket and an outer peripheral flange with a high sealing surface pressure, or an appropriate sealing means such as a bellows is used to prevent gas from leaking. It is possible to reliably seal the space between the two. In addition, the tubes can be attached and detached from the tube sheet extremely easily, and the time required for assembly and opening inspection can be greatly reduced. By using ceramic tubes, for example,
It becomes possible to process gases at temperatures exceeding 1000°C.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main parts of an embodiment in which the connection structure according to the present invention is applied to the lower end of a pipe, and FIG. 2 is a main part when the connection structure according to the present invention is applied to the upper end of the pipe. FIG. 11... Ceramic tube, 12... Tube sheet, 14.
...Cooling wall, 15... Holding hole, 16... Ceramic woven fabric, I7... Castable refractory layer, 18...
- Metal holder, 18... Outer flange, 20... Inner flange, 21... Buffer layer, 22... Annular projection,
23.25.29...Packskin, 24...Mounting flange, 26.30...Bellows ring, 2nd...
・Bellows. Figure 2

Claims (4)

[Claims] (1) An inorganic heat insulating layer surrounds the outer periphery of the connecting portion of the ceramic tube, a polymeric buffer layer surrounds the outer periphery of the inorganic heat insulating layer, and a metal holder surrounds the outer periphery of the buffer layer. and the metal holder are integrated, and the ceramic tube is held on the tube plate by the metal holder. A structure for connecting a tube and a tube plate. (2) The tube and tubesheet according to claim 1, wherein the inorganic heat insulating layer is composed of an inner layer made of ceramic fiber, paper, or woven fabric, and an outer layer made of castable refractory material. A structure that connects. (3) The polymer-based buffer layer is made of at least one of silicone rubber, fluororubber, or inorganic polymer, and is used to connect the tube and tube sheet according to claim 1 or 2. structure. (4) The metal holder is indirectly cooled by radiation with a low-temperature fluid such as water, and the buffer layer is kept cool by the metal holder. A structure that connects pipes and tube sheets.