JP2007212074A - High temperature heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high temperature heat exchanger having improved strength and durability by relaxing stress on flat tubes and a shell while suppressing an increase in manufacturing cost. <P>SOLUTION: The high temperature heat exchanger 11 comprises the plurality of flat tubes 12 provided side by side, a circular header plate 14 through which ends 13 of the flat tubes 12 pass to be fixed, and the shell 17 which is cylindrically formed to encircle the flat tubes 12 and to which an outer edge 15 of the circular header plate 14 is fixed. The circular header plate 14 has a through-hole 18 through which the ends 13 of the flat tubes 12 pass, a flat surface 20 formed near the outer periphery of the through-hole 18, and an inclined face 22 formed between the flat surface 20 and the outer edge 15. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat exchanger that exchanges heat between two fluids, and more particularly, to a high temperature heat exchanger in which a high-temperature fluid flows.

  Conventionally, a high-temperature heat exchanger has been used when recovering exhaust heat of a high-temperature gas discharged from a gas turbine or when generating hydrogen as fuel in a fuel cell.

  As shown in FIG. 3, this type of high-temperature heat exchanger 1 surrounds a plurality of flat tubes 2, a circular header plate 3 provided at an end of the flat tubes 2, and the flat tubes 2. The shell 4 is generally composed of a cylindrical shell 4.

  As shown in FIG. 4, the circular header plate 3 is provided with oval through-holes 5 in parallel according to the shape and number of ends of the flat tube 2. The flat tube 2 is fixed to the circular header plate 3 by penetrating the end portion of the flat tube 2 into the through hole 5 and brazing. In addition, the circular header plate 3 is fixed to the shell 4 by welding the outer edge of the circular header plate 3 to the inner surface of the end of the shell 4.

  The shell 4 is provided with a hot gas inlet 6 and a hot gas outlet 7 at both ends, respectively, so that the hot gas can flow through the flat tubes 2. Further, the shell 4 is provided with a cold gas inlet portion 8 and a cold gas outlet portion 9 in the vicinity of both end portions of the peripheral wall portion, and the low temperature gas is provided between the peripheral wall portion and the flat tube 2 in the shell 4 and each of them. The flat tube 2 can be circulated so as to face the hot gas.

  In the high temperature heat exchanger 1 having such a configuration, the high temperature fluid flowing into the flat tubes 2 from the high temperature gas inlet 6 opposes the low temperature fluid flowing into the shell 4 from the low temperature gas inlet 8. Circulates in the direction of each flat tube 2 and exchanges heat with the low temperature fluid, and then the hot gas and the low temperature gas are discharged to the outside from the high temperature gas outlet portion 7 and the low temperature gas outlet portion 9, respectively. .

  However, in the above-described high temperature heat exchanger 1, each flat tube 2 expands due to the circulation of the high temperature gas, resulting in a difference in the amount of expansion between the flat tube 2 and the circular header. In the joint portion with the plate 3, stress is concentrated particularly at the four corners (hatched portions in FIG. 4) of the flat tube 2, and there is a possibility that a joint failure such as a crack may occur at the joint portion.

Therefore, in order to absorb the difference in elongation between the flat tube 2 and the shell 4 and relieve the stress generated in the flat tube 2 and the shell 4, a bellows 10 is provided on the shell 4 as shown in FIG. (See, for example, Patent Document 1).
JP 2002-80203 A

  However, in the conventional high temperature heat exchanger described in the above-mentioned Patent Document 1, it is necessary to provide a bellows on the shell in order to alleviate the generation of thermal stress on the shell and the flat tube. There has been a problem that the manufacturing cost increases.

  The present invention has been made to solve the above-described problems, and while suppressing an increase in manufacturing cost, it can relieve stress generated in a flat tube and a shell, increase strength, and improve durability. It aims at providing the high temperature heat exchanger which can be performed.

  In order to achieve the above object, a high-temperature heat exchanger according to the present invention includes a plurality of flat tubes, a circular header plate through which ends of the flat tubes penetrate and are fixed, and surrounds the flat tubes. And a shell to which an outer edge portion of the circular header plate is fixed. The circular header plate includes a through hole through which an end of the flat tube passes, and a vicinity of an outer periphery of the through hole. A flat surface formed in the portion and an inclined surface formed between the flat surface and the outer edge portion are provided.

  In the high temperature heat exchanger, a flange portion may be formed in the through hole by burring.

  According to the present invention, the circular header plate is formed with an inclined surface from the outer edge portion to the vicinity of the outer periphery of the through hole, and the rigidity of the circular header plate is weakened. It is possible to disperse and reliably absorb the stress caused by the difference in elongation between the two. Therefore, it is possible to alleviate the occurrence of stress concentration in the flat tube or shell, and it is possible to reliably prevent the occurrence of poor bonding or leakage at the joint between the end of the flat tube and the circular header plate. Therefore, the strength and durability of the heat exchanger can be improved.

  In addition, since the generation of stress in the flat tube or the shell is alleviated, there is no need to provide an elongation absorbing member such as a bellows on the shell, so that the manufacturing cost can be reduced.

  Furthermore, when the flange portion is formed in the through-hole by burring, the joint area between the circular header plate and the flat tube can be increased, so that the strength of the joint portion can be increased. An excellent effect can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a high-temperature heat exchanger according to an embodiment of the present invention, and FIG. 2 is a view taken along the line AA in FIG.

  The high temperature heat exchanger 11 surrounds the flat tubes 12, a plurality of (in the figure, six) flat tubes 12, a circular header plate 14 through which an end portion 13 of the flat tubes 12 penetrates, and the flat tubes 12. The outer peripheral portion 15 of the circular header plate 14 is roughly constituted by a shell 17 fixed to the inner surface side of the end portion 16.

  An elliptical through hole 18 is formed in the circular header plate 14 in parallel with the shape and number of the end portions 13 of the flat tube 12. A flange portion 19 is formed in each through hole 18 by burring, and the end portion 13 of the flat tube 12 passes through each through hole 18, and this end portion 13 is brazed to the flange portion 19. Accordingly, the flat tube 12 is fixed to the circular header plate 14. Thus, since the flange part 19 is formed in each through-hole 18 by burring process, since the joining area between the circular header plate 14 and the flat tube 12 increases, the intensity | strength of a junction part can be raised.

  Further, a flat surface 20 is formed in the vicinity of the outer periphery of each through hole 18 of the circular header plate 14, and the outer periphery of the flat surface 20 has a substantially square shape, and the four corner portions 21 slightly protrude outward. It has an arc shape. Further, the circular header plate 14 is formed with an inclined surface 22 between the flat surface 20 and the annular outer edge portion 15, and the outer edge portion 15 is welded to the inner surface of the end portion of the shell 17. The plate 14 is fixed to the shell 17.

  In the high temperature heat exchanger 11 having such a configuration, the high-temperature fluid that has flowed into each flat tube 12 circulates between the peripheral wall portion and the flat tube 12 and between the flat tubes 12 in the shell 17. Exchanges heat with a cryogenic fluid. And during this heat exchange, since high temperature gas distribute | circulates in each flat tube 12, each flat tube 12 has a larger expansion | extension amount than the shell 17 with which low temperature gas distribute | circulates. For this reason, a difference occurs in the extension amount between each flat tube 12 and the shell 17, but the circular header plate 14 is formed with an inclined surface 22 from the outer edge portion 15 to the vicinity of the outer periphery of the through hole 18. Since the rigidity of the plate 14 is weakened, the stress is dispersed, and the difference in the extension amount is reliably absorbed by the circular header plate 14.

  Therefore, the concentration of stress on the flat tube 12 and the shell 17 can be alleviated, and poor bonding or leakage due to cracks or the like occurs at the four corner portions 21 of the joint between the end 13 of the flat tube 12 and the circular header plate 14. Therefore, it is possible to increase the strength of the heat exchanger and improve the durability. Furthermore, since it is not necessary to provide the shell 17 with an elongation absorbing member such as a bellows in order to reduce the generation of stress in the flat tube 12 or the shell 17, the manufacturing cost can be reduced.

It is a top view which shows the high temperature heat exchanger which concerns on embodiment of this invention. It is an AA arrow line view of FIG. It is sectional drawing which shows a prior art example. It is a top view which shows the circular header plate of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 High temperature heat exchanger 12 Flat tube 13 End part 14 Circular header plate 17 Shell 18 Through-hole 19 Flange part 20 Flat surface 22 Inclined surface

Claims (2)

A plurality of flat tubes arranged side by side;
A circular header plate through which the end of the flat tube penetrates and is fixed;
A shell that is formed in a cylindrical shape so as to surround the flat tube, and an outer edge portion of the circular header plate is fixed;
With
The circular header plate includes a through-hole through which an end of the flat tube passes, a flat surface formed in the vicinity of the outer periphery of the through-hole, and an inclined surface formed between the flat surface and the outer edge portion. And a high-temperature heat exchanger. The high temperature heat exchanger according to claim 1, wherein a flange portion is formed in the through hole by burring.

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