JP3541377B2 - Fastening structure between metal plate of ceramic heat exchanger tube and air header - Google Patents

Description

【００２１】
相対伸縮量βは
β＝０．３８２５−（０．０３３７＋０．１８４６＋０．１３４２）
＝０．０３
従ってβ＜０．０４×２．６＝０．１０４
であり高温時においても十分シール性を保っている。
【００２２】
なお、金属製弾性シールの原寸法は直径３．３ｍｍであった。
【００２３】
【実施例２】
温度８２５℃で使用されるセラミックフランジと金属製フランジの締結構造のテストを行った。締付枠の材質はＨＡ２４２（Ｈａｙｎｅｓ Ａｌｌｏｙ ２４２，Ｃｒ８％，Ｍｏ２５％，Ｆｅ２％，残Ｎｉ）、緩衝材はＨＴシート（日本ピラー工業（株）の商品名）、セラミックフランジの材質は窒化けい素、金属製弾性シールの外被の材質はインコネル６００、金属製フランジおよびボルトの材質はインコロイ８００Ｈであった。
【００２４】
計算結果を表２に示す。
【００２５】
【表２】

【００２６】
相対伸縮量βは
β＝０．８５１３−（０．０５０７＋０．２６０８＋０．５０５７）
＝０．０３４１
従ってβ＜０．０４×２．６＝０．１０４
であり高温時においても十分シール性を保っている。
【００２７】
なお、金属製弾性シールの原寸法は直径３．３ｍｍであった。
【００２８】
本発明は以上述べた実施形態や実施例に限定されるものではなく、発明の要旨を逸脱しない範囲で種々の変更が可能である。
【００２９】
【発明の効果】
以上述べたように本発明のセラミックフランジと金属製フランジの締結構造は常温から使用温度までの温度上昇によるセラミックフランジの厚さ、金属製フランジの厚さおよび締結ボルトの締付枠内面からの突出部分の長さの各熱膨張量の和を、締付枠内法の熱膨張量から引いた差が、金属製弾性シールの高温使用温度における復元可能な弾性変形量以内であるので、高温使用時においてもシール面圧が十分確保され、シール性が損われることがないなど優れた効果を奏する。
【図面の簡単な説明】
【図１】本発明のセラミックフランジと金属製フランジの締結構造の側断面図である。
【図２】締付枠の正面図である。
【図３】金属製弾性シールの平面図である。
【図４】図３のＡ−Ａ矢視断面図である。
【符号の説明】
１ セラミックフランジ（管板）
２ 金属製フランジ
３ 金属製弾性シール
４ 締付枠
５ 締結ボルト
６ 緩衝材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fastening structure between a ceramic flange and a metal flange used in a ceramic heat exchanger for preheating air of a high-temperature gas turbine.
[0002]
[Prior art]
Since the thermal efficiency of a gas turbine and a combined cycle using the gas turbine can be significantly improved by increasing the turbine inlet temperature, the turbine inlet temperature has been increased by the development of heat-resistant materials. In recent years, research on ceramic gas turbines using ceramics for turbine blades has been actively conducted, and an inlet temperature of 1400 to 1500 ° C. is planned for ceramic gas turbines. In a 300 kW class cogeneration system using such a ceramic gas turbine, a ceramic heat exchanger is planned to preheat heat by exchanging air that exits a compressor and enters a combustor with exhaust gas of a gas turbine. That is, in such a high-temperature gas turbine, the temperature of the turbine exhaust reaches 700 to 850 ° C., and since there is no metal heat exchanger, a ceramic heat exchanger using a ceramic heat transfer tube such as silicon nitride is used. Must.
[0003]
In such a ceramic heat exchanger, since the ceramics are used for the heat transfer tubes, the flanges that become the tube plates are also made of ceramics. On the other hand, since the air header is made of metal, its flange is also made of metal and it is necessary to fasten the ceramic flange and the metal flange.
[0004]
[Problems to be solved by the invention]
As described above, the ceramic flange and the metal flange are connected to each other in the bolt hole formed near the outer periphery of the flange by sandwiching the sealing material between the two flanges without examining the amount of thermal expansion due to a temperature change, as in a normal flange connection. If it is fastened by inserting and tightening with a nut, even if it can be sealed at room temperature, the thermal expansion in the thickness direction of the ceramic flange is small at a high temperature of about 700 ° C. The sum of the amounts becomes smaller than the amount of thermal expansion of the bolt, and the sealing surface pressure is reduced to cause leakage. Even if the sealing surface pressure is increased by increasing the amount of tightening at room temperature to prevent the leakage, the elastic limit of the seal will be exceeded. In addition, when the ceramic flange is perforated or threaded, it becomes a starting point of destruction, and the reliability is lowered in structural strength.
[0005]
The present invention has been devised in view of such problems of the prior art, and has a structure that is considered to be highly safe in terms of strength, and a ceramic flange that secures sealing surface pressure at high temperatures to prevent the occurrence of leaks. An object of the present invention is to provide a fastening structure for a metal flange.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the fastening structure of the ceramic flange and the metal flange of the present invention is arranged such that the ceramic flange and the metal flange face each other with the metal elastic seal therebetween, and have a U-shaped cross section so as to sandwich both flanges. The metal flange is covered with a metal flange, and the metal flange is pressed against the ceramic flange by a fastening bolt screwed into the frame. The sum of the respective thermal expansions of the thickness of the ceramic flange, the thickness of the metal flange, and the length of the protruding portion of the fastening bolt from the inner surface of the fastening frame due to the temperature rise of The difference is within the resilient elastic deformation amount of the metal elastic seal at the high use temperature.
[0007]
Further, it is preferable to sandwich a cushioning material between the inner surface of the fastening frame and the ceramic flange.
[0008]
Next, the operation of the present invention will be described. A ceramic flange and a metal flange are arranged with metal elasticity therebetween, and a fastening frame is put on the ceramic flange and the metal flange is fastened with a fastening bolt. The tightening amount should be within the resilient elastic deformation amount of the metal elastic seal. When the temperature is raised to the operating temperature in this state, the thickness of the ceramic flange, the thickness of the metal flange, and the length of the protruding portion of the fastening bolt from the inner surface of the fastening frame are each thermally expanded. Each material is selected so that the coefficient of thermal expansion of the metal of the fastening frame is sufficiently smaller than the coefficient of thermal expansion of the metal of the metal flange and the fastening bolt, so that the thickness of the ceramic flange and the thickness of the metal flange are selected. The difference between the sum of the thermal expansion of the bolt and the length of the protruding part of the fastening bolt from the inner surface of the fastening frame is subtracted from the thermal expansion of the fastening frame method. It can be within the deformation amount. Therefore, even in a high temperature state, the seal surface pressure of the metal elastic seal is sufficiently maintained, and no leak occurs.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side sectional view of a fastening structure between a ceramic flange and a metal flange according to the present invention. FIG. 2 is a front view of the fastening frame. FIG. 3 is a front view of the metal elastic seal. FIG. 4 is a sectional view taken along the line AA of FIG.
[0010]
FIG. 1 shows a part of a ceramic heat exchanger, which shows a fastening structure between a ceramic block constituted by a ceramic plate (flange) such as silicon nitride and a ceramic heat transfer tube fixed thereto and an air header having a metal flange. Is shown. In this ceramic heat exchanger, air flows inside the heat transfer tube, and exhaust gas flows outside the heat transfer tube.
[0011]
In the figure, reference numeral 1 denotes a ceramic flange to which a ceramic heat transfer tube 7 is fixed to form a tube sheet. Reference numeral 2 denotes a metal flange, which forms a part of a metal air header. Reference numeral 3 denotes a metal elastic seal, which will be described later in detail. Reference numeral 4 denotes a metal fastening frame having a U-shaped cross section as shown in the figure. As shown in FIG. 2, the fastening frame 4 is formed by dividing a rectangular annular frame into two parts 4b and 4c, and has a plurality of tap holes 4a formed on one side surface. Reference numeral 5 denotes a fastening bolt which is screwed with the tap hole 4a. Reference numeral 6 denotes a buffer material, which is obtained by adding an inorganic filler to a ceramic fiber mainly composed of silica and alumina and solidifying the ceramic fiber with an organic binder.
[0012]
As shown in FIGS. 3 and 4, the metal elastic seal 3 is made of a heat-resistant alloy such as Inconel or the like and formed into a rectangular ring-shaped coil spring 3a. The inner cover 3b is covered, and an outer cover 3c such as an inconel having a C-shaped cross section and formed in a ring shape is placed on the outer side, and the opening of the C-shape faces the outside. Use it by crushing it up and down.
[0013]
The ceramic flange 1 and the metal flange 2 are arranged to face each other with the metal elastic seal 3 interposed therebetween. A metal fastening frame 4 having a U-shaped cross section is placed so as to sandwich both flanges 1 and 2, and the metal flange 2 is elastically sealed with a plurality of fastening bolts 5 screwed to the fastening frame 4. They are sandwiched and pressed against the ceramic flange. When the temperature is raised from room temperature to 700 to 850 ° C., which is the operating temperature, the length L _c of the ceramic flange 1, the thickness L _h of the metal flange 2, and the length of the portion of the fastening bolt 5 protruding from the inner surface 4 d of the fastening frame. L _b is each thermal expansion, but the sum of the thermal expansion amount, minus the amount of thermal expansion clear width L _f of the clamping frame 4 is within recoverable elastic deformation of the elastic metal seal The materials and dimensions of the metal flange 2, the tightening bolt 5, and the tightening frame 4 are selected as described above, and the sealing surface pressure is maintained at a desired value, and there is no risk of leakage. Since the thermal expansion of the cushioning material 6 and the metal elastic seal 3 is small, they may be neglected. The resilient deformation of the metal elastic seal is considered to be about 4%.
[0014]
Hereinafter, the above items will be described using mathematical expressions.
It is assumed that the initial temperature of the fastening structure between the ceramic flange and the metal flange is T ₀ and the rigidity of each member is sufficiently high. Further, the effective dimension of each member is L, the temperature is T, the coefficient of linear expansion is α, and the thermal expansion amount is δ. That is, the suffix f is the inner dimension of the fastening frame 4, the suffix b is the length of the protruding portion of the fastening bolt 5 from the inner surface of the fastening frame, the suffix h is the thickness of the metal flange 2, and the suffix s is the metal elastic seal. 3, the subscript c represents the thickness of the ceramic flange 1, and the subscript k represents the thickness of the cushioning material 6, respectively.
[0015]
The thermal expansion amount δ of each member is represented by the following equation.
_{δ f = (T f -T 0} ) α f L f, δ b = (T b -T 0) α b L b
_{δ h = (T h -T 0} ) α h L h, δ s = (T s -T 0) α s L s
δ _c = (T _c −T ₀ ) α _c L _c , δ _k = (T _k −T ₀ ) α _k L _k
[0016]
In addition, from the knowledge of an experimental machine for a ceramic heat exchanger and a high-temperature sealing element test, it can be said that the fastening portion is sufficiently kept warm and the temperatures of the respective portions are almost the same. That is, when a common use temperature and _{T a T f ≒ T b ≒} T h ≒ T s ≒ T c ≒ T k = (T a)
It is.
[0017]
It is considered that the thermal expansion of the cushioning material 6 and the metal elastic seal 3 is sufficiently small. That is, δ _s ≒ δ _k ≒ 0
It is.
Therefore, when the relative amount of expansion and contraction in the use temperature T _a and beta,
β = δ _f − (δ _b + δ _h + δ _c ) = (T _a −T ₀ )
_{{Α f L f - (α} b L b + α h L h + α c L c)}
It is. Since recoverable elastic deformation amount at the use temperature of the metallic elastic seal 3 is believed to be about 4% of the thickness L _s at normal temperature use,
β ≦ 0.04L _s
It suffices to select α _f L _f , α _b L _b , and α _{h Lh such} that
[0018]
Embodiment 1
A test was conducted on the fastening structure of the ceramic flange and the metal flange used at a temperature of 700 ° C. The material of the tightening frame is 9Cr-1Mo steel, the cushioning material is HS sheet (trade name of Nippon Pillar Industry Co., Ltd.), the material of the ceramic flange is silicon nitride, the material of the metal elastic seal is Inconel 600, The material of the metal flange was SUS316, and the material of the bolt was SUS316.
[0019]
Table 1 shows the calculation results.
[0020]
[Table 1]

[0021]
The relative expansion and contraction amount β is β = 0.3825- (0.0337 + 0.1846 + 0.1342)
= 0.03
Therefore, β <0.04 × 2.6 = 0.104
Therefore, even at high temperatures, sufficient sealing properties are maintained.
[0022]
The original size of the metal elastic seal was 3.3 mm in diameter.
[0023]
Embodiment 2
A test was conducted on the fastening structure between the ceramic flange and the metal flange used at a temperature of 825 ° C. The material of the tightening frame is HA242 (Haynes Alloy 242, Cr8%, Mo25%, Fe2%, remaining Ni), the buffer material is HT sheet (trade name of Nippon Pillar Industry Co., Ltd.), and the ceramic flange material is silicon nitride. The material of the jacket of the metal elastic seal was Inconel 600, and the material of the metal flange and bolt was Incoloy 800H.
[0024]
Table 2 shows the calculation results.
[0025]
[Table 2]

[0026]
The relative expansion and contraction amount β is β = 0.8513− (0.0507 + 0.2608 + 0.5057)
= 0.0341
Therefore, β <0.04 × 2.6 = 0.104
Therefore, even at high temperatures, sufficient sealing properties are maintained.
[0027]
The original size of the metal elastic seal was 3.3 mm in diameter.
[0028]
The present invention is not limited to the embodiments and examples described above, and various changes can be made without departing from the gist of the invention.
[0029]
【The invention's effect】
As described above, the fastening structure of the ceramic flange and the metal flange of the present invention has the thickness of the ceramic flange, the thickness of the metal flange, and the protrusion of the fastening bolt from the inner surface of the fastening frame due to the temperature rise from room temperature to the operating temperature. Since the difference between the sum of the thermal expansions of the lengths of the parts and the thermal expansion of the method within the fastening frame is within the amount of elastic deformation that can be restored at the high operating temperature of the metal elastic seal, Even in such a case, an excellent effect is obtained such that the sealing surface pressure is sufficiently ensured and the sealing performance is not impaired.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a fastening structure of a ceramic flange and a metal flange of the present invention.
FIG. 2 is a front view of a fastening frame.
FIG. 3 is a plan view of a metal elastic seal.
FIG. 4 is a sectional view taken along the line AA of FIG. 3;
[Explanation of symbols]
1 ceramic flange (tube sheet)
2 Metal flange 3 Metal elastic seal 4 Tightening frame 5 Fastening bolt 6 Buffer material

Claims (3)

The tube plate of the ceramic heat exchanger and the metal flange of the air header are placed facing each other with a metal elastic seal in between, and a metal-made clamping frame with a U-shaped cross section is placed so as to sandwich them. A fastening structure between a tube plate of a ceramic heat exchanger and a metal flange of an air header in which a metal flange is pressed against a tube plate of a ceramic heat exchanger by a fastening bolt screwed into a frame. the thickness of the tube plate by a temperature rise up to the sum of the thermal expansion of the length of the projecting portion of the fastening frame inside surface of the thickness and the fastening bolts of the metal flange, thermal expansion of the clear width of the clamping frame minus the amount, positive a value and a metal resilient seal metal tube sheet and air header of ceramic heat exchanger, characterized in that is within the elastic deformation amount recoverable at high use temperatures Flange fastening structure. The fastening structure between the tube plate of the ceramic heat exchanger and the metal flange of the air header is sufficiently kept warm from the outside. 2. The fastening structure of claim 1, wherein the temperatures of the fastening frames are substantially the same. 3. The fastening structure of a tube plate of a ceramic heat exchanger and a metal flange of an air header according to claim 1 or 2, wherein a buffer material is interposed between the inner surface of the fastening frame and the tube sheet.

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