JPS6346395A - Structure of junction between tube and tube plate - Google Patents

Abstract

PURPOSE:To improve the workability when assembling the title tube and tube plate and to obtain a stable holding power with respect to the tube and a high airtightness by disposing heat expansive fillers around the outer periphery of the junction of tubes by holding a sand layer therebetween, loading a ring holder around the outer peripher ies of the sand layer and the fillers, and connecting the holder to the tube plate. CONSTITUTION:Heat expansive fillers are wound at the upper and lower positions by sandwitching sand layer 13 between the outer peripheral part at one end of a ceramic tube 11 and a ring holder 12. The filler 14 expands at a temperature equal to or higher than 400 deg.C. As the sand layer 13, for example, diatomaceous earth is used. The ring holder 12 holds the ceramic tube 11 and airtightness is held between the holder 12 and the tube 11. The holder 12 has a flange part 12a in the inner periph ery at the lower part to lock the filler 14 on the lower side and the flange part 12a around the outer periphery at the upper part is brought into engagement with the upper edge of a mounting hole 16 of the tube plate 15, bolts 18 are clamped through gaskets 17 to connect the holders 12 to tube plates 15. By this arrangement, and opera tion to hold airtightness and an operation to assemble the tube etc. to a can body can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to a connection structure between a tube and a tube plate, which is applied to, for example, a heat exchanger, a dust collector, and the like.

[Prior Art and its Problems] In recent years, heat exchanger tubes made of ceramics and porous tubes made of ceramics have been used in the fields of heat exchangers, collectors, etc. to treat high-temperature exhaust gas, etc.

Conventionally, these ceramic tubes were attached to tube sheets using a connection structure in which they were supported in holes, and the gaps between the ceramic tubes and the holes were filled with elastic, heat-resistant materials such as ceramic slopes and ceramic fibers by sandwiching sand between them. Something is known. This heat-resistant material is suitably compressed and packed into the gap, and its compression reaction force is used to grip the ceramic tube and connect the ceramic tube to the tube sheet. This improves the relationship between the fluid to be heated and the heating fluid.

In addition, Utility Model Application Publication No. 130-157579 shows another example of a joining structure between a tube and a tube sheet. In this example, a ceramic slope is installed in the gap between the hole and the ceramic tube and the tube sheet. The structure is such that the ceramic tubes are packed in a coiled manner, a sand filling layer is provided in the middle, and these are tightened with a gland.This joint structure prevents the bonding between the ceramic tubes and the tube sheet, which occurs during assembly and after heating. It can absorb the relative displacement caused by the difference in thermal expansion between the two, and it can also provide excellent holding power and airtightness at high temperatures.

However, in all of the above joint structures, the filling operation with heat-resistant materials such as ceramic lobes must be performed manually, and the filling operation is performed while compressing, which has the disadvantage of requiring a considerable amount of work time. Also,
Since each person's filling method tends to vary, the gripping force of the ceramic tube will also be affected, which will also affect the filling of the sand layer, and the quality of the ceramic tube! There was also the drawback of loss of uniformity in performance. Furthermore, poor workability causes high costs and also causes difficulty in quality control.

In addition, in the above bonded structure, in order to obtain higher quality and performance, it is necessary to compress the sand filling layer more strongly, and in order to hold the filling layer, the ceramic slope must be applied with a considerable pressing force. It needed to be compressed. This pressing force is generated by pressing the gland with a screw, but the pressing force of the gland cannot be efficiently converted into the gripping force of the ceramic slope.In fact, the pressing force of the gland solidifies the ceramic slope. In some cases, the elasticity was lost and the gripping force was reduced.

"Objective of the Invention" The object of the present invention is to provide good workability during assembly, to obtain stable gripping force on the pipe, and to provide high gripping force. The object of the present invention is to provide a connection structure between a tube and a tube sheet that can obtain the desired properties.

"Summary of the Invention" The connection structure between a tube and a tube sheet according to the present invention includes disposing a heat-expandable filler on the outer periphery of the connection part of the pipe with a sand layer sandwiched between the sand layer and the heat-expandable filler. Furthermore, a ring holder is attached to the outer periphery, and the ring holder and the tube plate are connected.

In the present invention, "heat-expandable filler" refers to a material formed by bonding a heat-expandable material and ceramic fibers with an organic binder to form, for example, a mat shape, which is heated to a predetermined temperature or higher. For example, it expands to about 1.3 to 3 times,
It means a material that has the property of not shrinking to its original size and maintaining its expanded state even if it is heated to 1000 ml after that. In this case, as the heat-expandable material, for example, perminiquirite, perlite, etc. are used, and as the ceramic v-kutsuite, for example, a fibrous inorganic material containing alumina or silica as a main component is used. Note that instead of this ceramic fiber, silica cloth can be used, and in that case, a structure in which a heat-expandable filler is sandwiched between the silica cloth may be used.Specific examples of such heat-expandable fillers include, for example: Examples include "Interum Mat" (product name: manufactured by Sumitomo 3M). This “Interam Mat”
Although many of them have anisotropy in the direction of expansion, the present invention is not limited to those exhibiting such anisotropic expansion, and can also employ those exhibiting isotropic expansion.

The present invention utilizes the expansion characteristics of such a heat-expandable filler. That is, a heat-expandable filler sandwiching a sand layer is interposed around the outer periphery of the connecting portion of the pipe, a ring holder is attached, and the temperature at which the heat-expandable filler expands is raised to 400° C. or higher, for example. As a result, the heat-expandable filler is expanded to firmly grip the tube, and the sand layer is compressed to provide high airtightness. Therefore, the assembly work can be standardized to a greater extent than in the prior art, and variations in performance due to differences in workers can be greatly reduced. The heat-expandable filler and the sand layer can absorb displacement caused by differences in thermal expansion in the axial or radial direction to some extent.

In addition, in the present invention, the pipes are not connected directly to the tube sheet, but are connected using a ring holder using a heat-expandable filler sandwiching the sand layer as described above. Simply attach the ring holder to the can body, etc., and work efficiency will be greatly improved.

"Embodiment of the Invention" FIG. 1 shows an embodiment of a connection structure according to the present invention.

In the gap between the outer periphery of one end of the ceramic tube 11 and the ring holder 12, a heat-expandable filler 14 is wound vertically with a sand layer 13 in between. The heat-expandable filler 14 expands when kept at a temperature of 400° C. or higher, and in this case, it is preferable that the sand layer 13 expands in the axial direction and radial direction of the ceramic tube 11. For example, diatomaceous earth is used. The ring holder 12 holds the ceramic tube 11 via a heat-expandable filler 14, and air is maintained between the ring holder 12 and the ceramic tube 11 by a sand layer 13.

The ring holder 12 has a flange +2b on the inner periphery of the lower part and locks the heat-expandable filler 14 on the lower side.
A flange portion 12a is provided on the outer periphery of the upper portion, and the flange portion 12a is mounted on the tube plate 15 and engages with the upper edge of the hole 16, and is connected and fixed by a bolt 18 through a gasket 17. Note that 44 and 45 are ceramic heat insulating materials.

Note that the ring holder 12 may be fixed, for example, through a bellows, and may have a structure that easily absorbs relative displacement between the ceramic tube 11 and the tube plate 15.

Furthermore, although the part of the ceramic tube 11 that is gripped by the ring holder 12 is the upper end in the above embodiment, it may be held at any of the upper, middle, or lower part of the ceramic tube 11. It may also be gripped at multiple parts.

Next, the ceramic tube 1 using the heat-expandable filler 14 is
1 and the ring holder 12 will be described. First, a heat-expandable filler 14 of a predetermined thickness is compressed and stuffed into the lower part of the gap between the ceramic tube 11 and the ring holder 12, and diatomaceous earth sand is filled from above to create a sand layer 1.
After forming 3, heat-expandable filler 1 is roughly spread over it.
4. Compress and pack again. Heat this part to 400℃.
When heated and maintained at the above predetermined temperature for a predetermined time, the upper and lower heat-expandable fillers 14 expand, and a pressing force is generated in the radial and axial directions of the ceramic tube 11. This pressing force is such that the ceramic tube 11 is gripped with sufficient force and at the same time the sand layer 1
3 to maintain sufficient airtightness.

The pressing force can be set to a desired value by appropriately selecting the thickness and shape of the heat-expandable filler 14. Once expanded, the heat-expandable filler 14 remains expanded to a greater extent than its original size, even though it may shrink slightly due to low temperature.
A stable pressing force can be maintained even after the ceramic tube 11 is assembled into the tube sheet 15 via the tube 4.

Incidentally, in the above embodiment, unevenness is provided on the inner peripheral surface of the ring holder 12 or the outer peripheral surface of the connecting portion of the ceramic tube 11 to increase the engagement force with the heat-expandable filler 14 and to roughen the gripping force of the ceramic tube 11. It can also be improved.

2 and 3 show another embodiment of the present invention in which the ceramic tube 11 is arranged vertically and applied to a heat exchanger.

In this embodiment, the upper and lower ends of the ceramic tube 11 are shown.

This is the case where the upper tube sheet 15 and the lower tube sheet 25 are connected. That is, the outer peripheral portion of the upper end of the ceramic tube 11 is held by the ring holder 12 via the heat-expandable filler 14, and the sand layer 13 is filled between the upper and lower heat-expandable fillers 14. This structure is similar to the previous embodiment. On the other hand, in the basic structure in which the outer periphery of the lower end of the ceramic tube 11 is filled with the heat-expandable filler 24 with the sand layer 23 interposed in the gap between the ceramic tube 11 and the ring holder 22, the lower end of the ceramic tube 11 is different from the upper end of the ceramic tube 11. It's the same. However, in this embodiment, as shown in FIG. 3, the heat-expandable filler 24 has a double structure in which the first heat-expandable filler 24a and the second heat-expandable filler 24b curve. The heat-expandable filler 24a is made to face the sand 1123. As this double heat-expandable filler 24, one that exhibits particularly large heat-expandability in one direction is used. That is, the first heat-expandable filler 24a has a main direction of expansion in the axial direction of the ceramic tube 11, and the second heat-expandable filler 24b has a main direction of expansion in the axial direction of the mix tube 11. It is radial.

In this way, by changing the expansion directions of the heat-expandable filler 24a and the second heat-expandable filler 24b, the heat-expandable filler 24a of the housing 1 grips the ceramic tube 11, and the second heat-expandable filler 24a grips the ceramic tube 11. The heat-expandable filler 24b is compressed into the sand layer 238 to an appropriate degree. Furthermore, in this embodiment, a difference can be provided between the gripping force of the heat-expandable filler 14 at the upper end and the gripping force of the heat-expandable filler 24 at the lower end. , the heat-expandable filler 2 applies a gripping force to the extent that the ceramic tube 11 slides upward when it thermally expands.
4 has been given a gripping force to prevent the ceramic tube 11 from slipping.

According to this embodiment, when the ceramic tube 11 is assembled into the can body, the ring holders 12 and 22 are assembled in advance and transported to the site, and the attachment is lowered from the top of the tube plate 15 through the hole 16, and then The work is completed by simply tightening the bolts 28 through the gaskets 27 and the bolts 18 through the gaskets 17, respectively, depending on the position and upper part thickness. Therefore, a dramatic improvement in workability can be achieved, and airtight reliability is also significantly improved.

FIG. 4 shows still another embodiment of the present invention in which the ceramic tube 11 is made horizontally thick and applied to a heat exchanger. In this embodiment, the structure of the present invention is applied to one side of the ceramic tube 11, and the conventional structure is applied to the other side. In this case, the parts of the structure of the present invention are almost the same as those in the first embodiment, so they are indicated by the same reference numerals and the explanation thereof is omitted.

In this embodiment, when assembling the ceramic tube 11 into the can body, the tube plate 15 is inserted through the hole 16 while being gripped by the ring holder 12 in advance, and the gasket 1
Bolts 18 are tightened through holes 7 to connect ring holder 12 to tube plate 15. Thereafter, on the tube plate 25 side, connections are made according to the conventional structure, that is, the ceramic tubes 11
The end of the metal ring 30 and the ceramic tube 11 are sandwiched with a sand layer 31, and the ceramic lobe 32 is stuffed into the gap between the metal ring 30 and the ceramic tube 11, the gland 33 is fitted, and the nut is tightened by 34%. As a result, appropriate gripping force and airtightness can be obtained on the tube sheet 25 side, while the structure of the present invention on the tube sheet 15 side has excellent airtightness due to the sand layer 13 and excellent airtightness due to the heat-expandable filler 14. Provides solid gripping force. Moreover, since the ring holder 12 is simply fixed with the gasket 17 on the tube plate 15 side, the workability of assembling is greatly improved.

FIG. 5 shows a heat exchanger with multiple buses in which heated gas is passed back and forth between upper and lower headers through ceramic tubes 11.
In Figure 0, which shows the case where the structure of the present invention is applied, a two-bus structure is shown to simplify the explanation.
In this embodiment, a bellows 40 is connected to a ring holder 12 that grips the upper end of the ceramic tube 11, and the bellows 40 actively controls the relative displacement between the ceramic tube 11 and the tube sheet 15. It has a structure that absorbs Headers 41 and 42 are connected to the ceramic tube 11 from above the tube sheet 15. The rest of the structure at the upper end of the ceramic tube 11 is the same as that of the first embodiment, so a description thereof will be omitted. However, the upper end of the ceramic tube 11 is firmly held by the ring holder 12 via the heat-expandable filler 14, and the sand layer 13 is compressed at an appropriate degree by the heat-expandable filler 14. On the other hand, the lower end of the ceramic tube 11 also
The sand layer 23 is firmly held by the heat-expandable filler 22 via the heat-expandable filler 24, and the sand layer 23 is compressed to an appropriate density by the heat-expandable filler 24. The lower end portions of the ceramic tubes 11 are communicated through a common header 43. In this structure, the fluid to be heated enters through the header 41 and flows to the common via the ceramic tube 11 and from the cedar 43 to the header 42 via another ceramic tube 11. According to this embodiment, ease of installation is improved, and higher airtightness can be obtained than in the embodiments shown in FIGS. 2 and 3.

Although the above embodiment has been explained using a heat exchanger as an example, it is also possible to apply the present invention to a collection device for high-temperature gas.

``Effects of the Invention'' As explained above, according to the present invention, the outer periphery of the connecting portion of a pipe is held by a ring holder via a heat-expandable filler with a sand layer sandwiched in between, and the ring holder and the tube sheet, the expansion of the heat-expandable filler acts as a pressing force on the tube and the sand layer, firmly gripping the tube and compressing the sand layer to maintain high aeration. be able to.

Further, since the tubes are not connected directly to the tube plate but are connected through the ring holder, it is extremely easy to assemble, for example, a heat exchanger into a can body.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a basic embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the invention, FIG. 3 is a partially enlarged sectional view of FIG. 2, and FIGS. FIG. 5 is a sectional view showing still another embodiment of the present invention. In the figure, 11 is a ceramic tube, 12.22 is a ring holder, 13.23 is a sand layer, 14.24 is a heat-expandable filler, 15.25 is a tube plate, 16 is a mounting hole, 17 is a gasket, 18 is a bolt, and 40 is a bellows. Special scam originator Asahi Glass Co., Ltd.

Claims (3)

[Claims] (1) A heat-expandable filler is placed around the outer periphery of the pipe connection, sandwiching a sand layer, and a ring holder is attached to the outer periphery of the sand layer and the heat-expandable filler, and the ring holder and tube sheet A connection structure between a tube and a tube sheet, characterized in that a tube and a tube sheet are connected to each other. (2) In claim 1, the heat-expandable filler includes a first heat-expandable filler that expands primarily in the axial direction of the tube, and a second heat-expandable filler that expands primarily in the radial direction of the tube. A connection structure between a tube and a tube sheet, comprising a heat-expandable filler. (3) A connection structure between a tube and a tube plate according to claim 1 or 2, wherein the tube is a ceramic tube.