JPS6256793A - Ceramics heat exchanger - Google Patents

Abstract

PURPOSE:To permit relative displacement in a connecting part between ceramics heat transfer tubes and a tube plate and prevent leakage of fluid in the connecting part by a method wherein a retaining ring is abutted by pressure against one end of the ceramics heat transfer tube by a pressure means while the other end of the same tube is supported by abutting it by pressure against the receiving surface of the other tube plate. CONSTITUTION:A spring 36 is arranged between a retaining ring 29 and the tip of a tube 34 to abut the retaining ring 29 against one end face of a heat transfer tube 22, while the other end face of the heat transfer tube 22 is abutted against the receiving surface 30 of the other tube plate 24 by the energizing force of the spring 36. The main body of a heat exchanger 21 and the tube plates 23, 24 are made of metal and thermal expansion coefficient of the ceramics heat transfer tube 22 is different from that of the metallic parts, therefore, relative displacement is generated due to the difference of thermal expansion coefficients. The axial relative displacement of the heat transfer tube 22 is absorbed by a mechanism wherein the spring 36 expands or contracts to move the retaining ring 29 axially and an expansion coupling 38 is expands or contracts. On the other hand, the radial displacement of the heat transfer tube 22 is absorbed by a mechanism wherein the radial displacement is allowed in some degree by the expansion coupling to slide both end surfaces of the heat transfer tube 22 with respect to the contacting surface thereof.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a heat exchanger in which both ends of a ceramic heat exchanger tube are supported by a pair of opposed tube sheets, and in particular to a heat exchanger that supports both ends of a ceramic heat transfer tube and Structural improvements (related to this)

"Prior art and its problems" Most of the shell-and-tube heat exchangers currently in use have heat exchanger tubes, tube sheets, and other structures made of metal, and the connections between the tube sheets and heat exchanger tubes are This is done by methods such as welding and pipe expansion.
There was also no leakage between the heating and the heated fluid. However, metal heat exchanger tubes have a limit to their heat resistance temperature.
Heat exchange of fluids with temperatures above 800-900°C was not possible.

Therefore, some pages use ceramic tubes as heat transfer tubes. However, unlike metals, ceramics break without being deformed when an external force is applied to them. I had to be 1 no to allow for sudden changes.

Conventionally, a structure as shown in FIG. 10, for example, has been adopted as a connection structure between a ceramic heat exchanger tube and a tube plate. That is, the end of the ceramic heat exchanger tube 11 is made of metal tube plate 12.
The fluid flow hole is inserted through the hole.

A cylindrical portion 13 surrounding the heat transfer tube V++ is formed in the tube plate 12. A pair of heat-resistant seal rings 14. The space between the seal rings 14 and 14 is filled with seal sand 15. The groove is pressed by the outer seal ring 14 or the presser lid 16. Note that 17 is a heat insulating material. The heat exchanger tubes 11 are supported through the sealing sand 15 so as to be movable relative to the tube plate 12.

However, in the above connection 4U filter, it is possible to completely prevent fluid leakage by installing J3 at the seal part between the heat exchanger tube 11 and the tube plate 12. For example, it is possible to completely prevent fluid leakage between the heating fluid and the heated fluid. When the pressure difference becomes 1 atmosphere or more, fluid leakage can no longer be ignored. Therefore, it cannot be used in heat exchangers that cannot tolerate fluid leakage or in heat exchangers with high pressure or high differential pressure.

Object of the invention j An object of the present invention is to solve the above-mentioned problems of the prior art, to enable relative displacement at the connection between the ceramic heat exchanger tube and the tube sheet, and to prevent fluid leakage at the connection. Our objective is to provide a ceramic heat exchanger with

``Structure of the Invention j'' That is, the present invention provides a ceramic heat exchanger in which both ends of a ceramic heat exchanger tube are supported by a pair of metal tube sheets arranged opposite to each other, in which the fluid flow of one of the tube sheets is A retaining ring is arranged corresponding to the hole, and the retaining ring is directly or indirectly pressed against one end surface of the ceramic heat exchanger tube by a pressurizing means provided between the retaining ring and the tube sheet. The other end surface of the heat exchanger tube is directly or indirectly pressed against and supported by the receiving surface of the other tube sheet by the biasing force.

Therefore, relative displacement in the axial direction of the heat exchanger tubes due to dimensional errors or differences in coefficient of thermal expansion can be absorbed by movement of the retaining ring. First, the relative displacement of the heat exchanger tubes in the radial direction can also be absorbed by the sliding contact surfaces between the retaining ring and the receiving surface of the other tube sheet. Since the contact surface is pressed by the pressurizing means, leakage of fluid is also prevented.

According to a preferred embodiment of the present invention, both end surfaces of the ceramic heat exchanger tube are directly pressed against the retaining ring and the receiving surface, and the contact surfaces thereof are smoothed.

In this way, by smoothing the contact surface, it becomes easier to slide, which makes it easier to absorb the relative displacement of the heat exchanger tube in the radial direction, and also improves adhesion. Fluid leakage is also more reliably prevented. Note that smoothing here means that the surface roughness of each contact surface is finished to 6.3S or less, preferably 0.8S or less, and is shaped so that it is distributed over the entire circumference of the end face. 0 less.

According to another preferred embodiment of the present invention, both end surfaces of the ceramic heat exchanger tube are pressed against the retaining ring and the receiving surface via connecting rings, respectively. By interposing the connecting ring in this manner, when the ceramic heat exchanger tube is formed into a cylindrical shape that is easy to mold, the end portion can be changed into a desired shape by the connecting ring. are usually made of metal or preferably, but the connecting ring must be made of ceramic.

In other words, the connecting ring itself becomes high temperature when it comes into contact with the high-temperature heat transfer tube, so it satisfies the requirements of having high heat resistance and low thermal conductivity so as not to transfer the heat of the heat transfer tube to the retaining ring. This is because it has to be something.

The connecting ring may be disc-shaped, like the retaining ring, or, according to a less preferred embodiment of the invention, the connecting ring has an inner diameter with a tapered cross-section. By making the connecting ring have a tapered inner diameter, it is possible to arrange a cylindrical heat insulating material on the inner circumference of the connecting ring without reducing the cross-sectional area of the flow path. It is possible to protect the metal parts such as the retaining ring (position) from the high temperature fluid flowing inside the heat transfer tube.

In addition, when using the connection ring 1, it is recommended that the contact surfaces of the ceramic heat exchanger tube, connection ring, retaining ring, and receiving surface be smoothed for the same reason as mentioned above. In fact, according to a particularly preferred embodiment of the present invention, a cylindrical body extending in the axial direction of the ceramic heat transfer tube is formed on the retaining ring, and this cylindrical body is in sliding contact with the inner periphery of the through hole of one of the tube sheets. According to this, the retaining ring can be supported axially displaceably relative to the tube sheet, and the air distribution between the retaining ring and the tube sheet can be maintained by the cylindrical body.

According to a particularly preferred embodiment of the invention, said pressurizing means is constituted by a spring or a hydraulic cylinder. In this case, various types of springs such as coil springs and disc springs can be used.

According to a particularly preferred embodiment of the present invention, the tube sheet has a water-cooled structure, and the retaining ring and the pressurizing means are arranged in a portion surrounded by the water-cooled structure. According to this, the retaining ring and the pressurizing means are radiantly cooled by the water cooling structure, so that sufficient heat resistance can be imparted.

The ceramic heat transfer tube used in the present invention is preferably one that has sufficient strength and good thermal conductivity even if it has a small wall thickness. Specifically, even if the wall thickness is about 5 to I Omm, it is desirable to have a bending strength of 20 kq, m♂ or more and a thermal conductivity of 20 kcal/m/h/ or more. , materials that easily satisfy these requirements (
), silicon carbide is most preferred. On the other hand, the connecting ring is suitably made of silicon nitride or the like, which has the same strength but has a relatively low heat conductivity.

In addition, in the present invention, the retaining ring and the connecting ring may be provided in common to a small number of ceramic heat exchanger tubes, or the dimensional accuracy and thermal expansion coefficient of ceramic heat exchanger tubes may be determined for each individual component due to the characteristics of the material. Because it is easy to vary,
Preferably, a retaining ring and a connecting ring are provided for each ceramic heat exchanger tube.

``Embodiments of the Invention'' FIG. 1 shows almost the entire body of a heat exchanger □ in which the present invention is implemented. This heat exchanger 21 has a plurality of ceramic heat exchanger tubes 22, and the heat exchanger tubes 22 are supported at both ends by a pair of tube sheets 23 and 24.
．． 24, there is no flow path 20 of the heating waterfall body 1a that crosses the heat transfer tube 22. In addition, the outside of the tube plate 23, 24 is header 25, 267: each is surrounded by three J, passing from one header 26 through the inside of the heat transfer tube 22 to the head 9'-2 of the left side.
A flow path 27 for the heated fluid C flowing out into the tube plate 23 and 24 is formed with a water-cooled jacket 28, respectively. It is supported by a portion surrounded by a water cooling jacket 28.

Both ends of the heat exchanger tube 22 are expanded, and the end faces are smoothed. One end surface of the heat exchanger tube 22 is pressed against a receiving surface on the lower surface of a disc-shaped retaining ring 29, and the other end surface of the heat exchanger tube 22 is pressed against a receiving surface 30 fixedly provided on the tube plate 24. In this case, the receiving surface of the retaining ring 29 and the receiving surface 30 of the tube plate 24 are also smoothed, and the heat exchanger tubes 22
It is designed to come into close contact with the end surface of. Note that the tube plate 23.
The inner and outer surfaces of 24 are each covered with a heat insulating material 31.

2 and 3 show the connection structure of the retaining ring 29 portion of the heat exchanger 21. As shown in FIG.

A guide rod 32 is provided upright on the retaining ring 29.

A plurality of guide rods 32 (eight in this embodiment) are provided along the peripheral edge of the retaining ring 29. On the inner lower surface of the annular support 33 fixed to the upper surface of the tube plate 23,
A tube 34 is provided corresponding to the position of the guide rod 32. The tip of the guide rod 32 is inserted into the cylinder 34. Therefore, the retaining ring 29 is supported so as to be movable along the axial direction of the heat exchanger tube 22 via the guide rod 32. At the outer periphery of the guide rod 32, the retaining ring 29 and the cylinder 3
A spring 36 is disposed between the four tips, and the spring 36 and the holding l-ring 29 are pressed against one end surface of the heat transfer tube 22. Note that due to this biasing force, as described in 1 above, the end surface of the heat transfer tube 22 is pressed against the receiving surface 30 of the other tube plate 24.The retaining ring 29 and the support 3
3, an expansion joint 38 is installed so as to surround the flow hole 37 for the heated fluid C. Further, a cylindrical heat insulating material 39 forming the peripheral wall of the circulation hole 37 is arranged inside the retaining ring 29 and the support 33, and its tip is tapered and enters the enlarged diameter part of the heat exchanger tube 22. . In addition, Fig. 1, Fig. 2, Fig. 3, and Fig. 4, Fig. 6, which will be described later,
In FIGS. 7 and 8, the spring 36 is shown schematically using a dashed line.

In the above configuration, the heating fluid H flows through the flow path 20, contacts the heat exchanger tube 22, and heats the heat exchanger tube 22.

The heated fluid C flows from the header 26 through the heat exchanger tube 22 to the header 25 through the flow path 27, and as the heated fluid C passes through the heat exchanger tube 22, heat is exchanged and heated. Incidentally, it is also possible to flow the heated fluid C through the flow path 20 and the heated fluid H through the flow path 27. By the way, since the main body and tube plates 23 and 24 of the heat exchanger 21 are made of metal, their thermal expansion coefficients are different from those of the ceramic heat exchanger tubes 22, and a relative displacement occurs due to the difference in thermal expansion coefficients. The relative change Ω in the axial direction of the heat exchanger tube 22 is:
This is absorbed by the expansion and contraction of the spring 36, the axial movement of the retaining ring 29, and the concomitant expansion and contraction of the expansion joint 38. Further, the radial displacement of the heat exchanger tube 22 is absorbed by the expansion/contraction M8,38 allowing a certain degree of radial displacement or by acting between the contact surfaces provided on both end surfaces of the heat exchanger tube 220. In this case, since all contact surfaces are smoothed, sliding is facilitated. Since the contact surfaces at both end faces of the heat transfer tube 22 are flattened by smoothing, leakage of fluid at these portions is sufficiently prevented. Roughly speaking, in this example,
Since the expansion joint 38 is provided, the tightness between the retaining ring 29 and the support 33 is also maintained. In addition, the spring 36 and the expansion joint 38 are made of metal and are expected to be vulnerable to high temperatures, but the water-cooling jacket 28 surrounds their outer peripheries, allowing them to be radiantly cooled, and they are placed outside the heat insulating material 39. Heat damage is prevented because the temperature is -C.

FIG. 4 shows another embodiment in which the connection structure of the retaining ring 29 is changed. In this embodiment, a cylindrical body 40 is erected upward from the inner upper surface of the retaining ring 29.
0 is in sliding contact with the inner periphery of an annular support 41 extending from the tube plate 23 and forming a hole. A seal ring 42 made of heat-resistant rubber such as silicone rubber is interposed between the cylindrical body 40 and the support 41. Further, a plurality of guide rods 43 are erected in the axial direction on the lower surface of the support 41, and the lower ends of the guide rods 43 are inserted into holes provided at the peripheral edge of the retaining ring 29. A spring 36 is installed between the retaining ring 29 and the support 41 on the outer periphery of the guide rod 43. Therefore, the retaining ring 29 is movable in the axial direction while being guided by the cylindrical body 40 and the guide rod 43, and is pressed against the end surface of the heat exchanger tube 22 by the spring 36. Moreover, since the outer periphery of the heat insulating material 39 is surrounded by the cylinder 40 between the retaining ring 29 and the support 41, the memory in that part is maintained.

FIG. 5 shows another embodiment in which the connection 1j1 structure of the retaining ring 29 portion is changed. In this example,
A piston 44 is attached to the tip of the guide rod 32 erected on the retaining ring 29 , and the piston 44 is inserted into a cylinder 45 formed in the support 41 of the tube plate 23 .

Then, pressurized fluid is introduced into the cylinder 45 above the piston 44 (through a pressurized fluid introduction passage 46). The fact that the joint 3 is provided is the same as in FIG. It is pressed against the end face of the heat exchanger tube 22.

6 and 7 show another embodiment in which the connection structure of the retaining ring 29 portion is changed. In this embodiment, both end surfaces of the heat exchanger tube 22 are connected to connection rings 47, respectively.
It is pressed into contact with the retaining ring 29 and the receiving surface 30 through it. The connecting ring 47 has a tapered inner diameter in cross section, and one end surface of the ceramic heat transfer tube 22 contacts the smaller diameter end surface of the connecting ring 47.
The retaining ring 29 or the receiving surface 3o comes into contact with the end face of the larger diameter of the retaining ring 29 or the receiving surface 3o. Further, the tip of the cylindrical heat insulating material 39 forming the peripheral wall of the flow hole 37 is not tapered and enters the widened portion of the connecting ring 47 . Other configurations are similar to the embodiments shown in FIGS. 1, 2, and 3. In this embodiment, since the diameter of the connecting ring 47 is enlarged by a certain amount, the ceramic heat exchanger tube 22 can be formed into a cylindrical shape with the same diameter almost in the length direction, which has the advantage of making it easier to manufacture the ceramic heat exchanger tube 22. .

FIG. 8 shows another embodiment in which the connection structure of the heat exchanger tubes is changed. In this embodiment as well, the end of the ceramic heat exchanger tube 22 is pressed against the retaining ring 29 via the connecting ring 478. The rest of the structure is the same as the embodiment shown in FIG.

FIG. 9 shows another embodiment in which the connection structure of the heat exchanger tubes is changed. In this embodiment as well, the ends of the ceramic heat exchanger tubes 22 are connected to the retaining ring 29 through the connecting resig 47. The rest of the structure is the same as the embodiment shown in Fig. 5.

In general, in any case where the connection structures shown in FIGS. 4 and 8 are used, a fluid pressure cylinder may be used as the pressurizing means, as in the example shown in FIG. 5, instead of the subring 36. good.

"Effects of the Invention" As explained above, according to the present invention, the retaining ring provided on one tube sheet is brought into direct or indirect pressure contact with one end surface of the ceramic heat exchanger tube by the pressurizing means. Since the other end surface of the ceramic heat transfer tube is brought into direct or indirect pressure contact with the other tube sheet by force, axial displacement due to the difference in thermal expansion coefficient or dimensional error can be absorbed by the axial displacement of the retaining ring. I can do it. Moreover, displacement of the heat exchanger tube in the radial direction can also be absorbed by the misalignment of each contact surface at both ends of the ceramic heat exchanger tube. Roughly,
Since the contact surfaces at both end faces of the ceramic heat transfer tube are small, fluid leakage can be prevented. With a sharp cut,
It can also be applied to heat exchange in fields where the temperature exceeds 1000°C and leakage is not allowed.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the ceramic heat exchanger according to the present invention, Fig. 2 is a partial sectional view showing the connection structure of the retaining ring portion of the heat exchanger, and Fig. 3 is A in Fig. 2. −
A sectional view taken along line A, FIGS. 4 and 5 are partial sectional views showing other embodiments in which the connection structure of the retaining ring portion of the heat exchanger is changed, and FIG. 6 is a ceramic heat exchanger according to the present invention. 7 is a sectional view showing another embodiment of the exchanger; FIG. 7 is a partial sectional view showing the connection structure of the retaining ring portion of the heat exchanger; FIG.
Fig. 9 is a partial sectional view showing an embodiment of the heat exchanger with a different 1M connection structure for the retaining ring portion, and Fig. 10 is a partial sectional view showing a conventional example of the connection structure for the end of the ceramic heat exchanger tube. It is a diagram. In the figure, 21 is a heat exchanger, 22 is a heat exchanger tube, 23.24 is a tube plate, 25.26 is a heat exchanger, 27 is a flow path, 28 is a water cooling jacket, 29 is a retaining ring, 30 is a receiving surface, 36 is a tin ring , 37 is a communication hole, 38 is an expansion joint, 40 is a cylinder, 14 is a piston, and 45 is a cylinder. Patent applicant: Asahi Glass Co., Ltd. Agent: Shigedo Matsui Kunio Miura Yoshimi Sasayama Figure 3 Figure 6 Figure 8 Figure 9

Claims (8)

[Claims] (1) In a ceramic heat exchanger in which both ends of a ceramic heat transfer tube are supported by a pair of metal tube sheets arranged opposite to each other, a retaining ring is arranged corresponding to the fluid flow hole in one of the tube sheets. The retaining ring is directly or indirectly pressed against one end surface of the ceramic heat exchanger tube by a pressurizing means provided between the retainer ring and the tube sheet, and the biasing force causes the ceramic heat exchanger tube to A ceramic heat exchanger characterized in that the other end surface of the ceramic heat exchanger is directly or indirectly pressed against and supported by the receiving surface of the other tube sheet. (2) A ceramic heat exchanger according to the first aspect of the present invention, wherein both end surfaces of the ceramic heat exchanger tube are directly pressed against the retaining ring and the receiving surface, and the contact surfaces thereof are smoothed. (3) The ceramic heat exchanger according to claim 1, wherein both end surfaces of the ceramic heat exchanger tube are pressure-welded to the retaining ring and the receiving surface via connecting rings, respectively. (4) The ceramic heat exchanger according to claim 3, wherein the connecting ring has an inner diameter with a tapered cross section. (5) The ceramic heat exchanger according to claim 3 or 4, wherein contact surfaces of the ceramic heat exchanger tube, the connection ring, the retaining ring, and the receiving surface are smoothed. (6) In any one of claims 1 to 5, the retaining ring is formed with a cylindrical body extending in the axial direction of the ceramic heat exchanger tube, and the cylindrical body extends through one of the tube sheets. A ceramic heat exchanger that is in sliding contact with the inner circumference of the hole. (7) A ceramic heat exchanger according to any one of claims 1 to 6, wherein the pressurizing means is a spring or a fluid pressure cylinder. (8) In any one of claims 1 to 7, the tube sheet has a water-cooled structure, and the retaining ring and the pressurizing means are arranged in a portion surrounded by the water-cooling structure. Ceramic heat exchanger.