JPS60125460A - Deformation absorbing bellows - Google Patents

Abstract

PURPOSE:To enhance the high-temperature fatigue strength of a deformation absorbing bellows made of a material whose high temperature fatigue strength for maintaining the material against the tensile strains corresponding to an internal and an external media is different thereto, by making the crest and trough of the bellows different in flexural rigidity from each other. CONSTITUTION:The radius r1 of curvature of the crest 3 of a deformation-absorbing bellows is made 2.2 times as much as that r2 of its trough 4. The rigidity of the crest 3 is made higher than that of the trough 4 so that the strain of the crest is about one third of that of the trough. When the bellows is compressively deformed, a tensile and a compressive strains are caused in the outer and inner portions of the crest 3 and a compressive and a tensile strains are caused in the outer and inner portions of the trough 4, respectively. The strain of the crest 3 is about 0.5%, while that of the trough 4 is about 1.5%. The outer portions of both the crest 3 and the trough 4 are broken by about 1,200 times of repetition of the deformation of the bellows. The life of the bellows is about 4 times as long as that of a conventional bellows.

Description

【発明の詳細な説明】 〔発明の利用分野〕 本発明は変形吸収ベローズに係り、特に、液体すトリウ
ム等の非酸化性媒体を内側に有して高温で変形を保持す
るに好適な変形吸収ベローズに関する。Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to a deformation-absorbing bellows, and particularly to a deformation-absorbing bellows having a non-oxidizing medium such as liquid storium inside and suitable for retaining deformation at high temperatures. Regarding bellows.

【発明の背景〕[Background of the invention]

第１図に示す従来例は、高温増殖炉の配管に設置された
変形吸収ベローズで、オーステナイト系ステンレスｍ５
Ｏ３３０４製である。ベローズの外側は大気１で、内側
には約５σＯ℃の液体す１ヘリウム２が流れている。ベ
ローズの山部３及び谷部４はＵ形をしている。それらの
波形半径「１゜ｒ２は等しく、肉厚ｔは全長に亘って一
様である７ベローズの両端には厚肉のリング５が存在し
、それぞれ他の配管（図示せず）に溶接される。The conventional example shown in Figure 1 is a deformation-absorbing bellows installed in the piping of a high-temperature breeder reactor.
Made of O3304. The outside of the bellows is the atmosphere 1, and the inside is flowing liquid helium 2 at about 5σO°C. The ridges 3 and troughs 4 of the bellows are U-shaped. Their waveform radii ``1゜r2 are equal, and the wall thickness t is uniform over the entire length. 7 There are thick-walled rings 5 at both ends of the bellows, each of which is welded to another pipe (not shown). Ru.

以上の構成で炉を起動すると配管等の機器は熱膨張し、
ベローズはそれを吸収して圧縮変形する。When the furnace is started with the above configuration, piping and other equipment will thermally expand.
The bellows absorbs it and compresses it.

炉の運転中、長時間に亘ってこの状態が保持されるが、
ベローズ山部３の外面は引張ひずみが生じた状態で大気
による高温酸化を受けるため、炉の起動停止が繰返さｉ
した場合、他の部分よりも疲労破壊の可能性が大である
。This state is maintained for a long time while the furnace is operating, but
The outer surface of the bellows peak 3 undergoes high-temperature oxidation in the atmosphere under tensile strain, causing the furnace to repeatedly start and stop.
If this occurs, the possibility of fatigue failure is greater than other parts.

〔発明の目的〕[Purpose of the invention]

本発明の目的は、高温疲労強度を向」ニさせた変形吸収
ベローズを提供することにある。An object of the present invention is to provide a deformation-absorbing bellows with improved high-temperature fatigue strength.

〔発明の概要〕[Summary of the invention]

本発明は、第２図に例示する高温疲労強度に及ぼす環境
効果に基づいてなされたものである。すなわち、第２図
には５ＵＳ３０４鋼について、５５０℃の大気中及び液
体ナトリウムを模擬した真空中において引張ひすみ又は
圧縮ひずみ側で１時間の保持を与えた場合の疲労試験結
果を示す。The present invention was made based on the environmental effects on high temperature fatigue strength as illustrated in FIG. That is, FIG. 2 shows the fatigue test results for 5US304 steel when it was held for 1 hour at the tensile strain or compressive strain side in the atmosphere at 550° C. and in a vacuum simulating liquid sodium.

真空中の引張保持と圧縮保持及び大気中の圧縮保持の３
者はいずれも疲労強度が高いが、大気中の引張保持は疲
労強度を大きく低下させており、高温酸化環境中におけ
る引張ひずみ保持が寿命を低下させることが分る。本発
明はこの点に着目してなされたもので、山部と谷部のた
わみ剛性を異ならせて高温酸化環境中で引張ひずみ保持
を受ける部分の最大引張ひずみを小さくするようにした
ものである。3: Tensile holding and compression holding in vacuum and compression holding in the atmosphere
All specimens have high fatigue strength, but holding tensile strain in the atmosphere greatly reduces fatigue strength, indicating that holding tensile strain in a high-temperature oxidizing environment reduces life. The present invention has been made with attention to this point, and the flexural rigidity of the peaks and valleys is made different to reduce the maximum tensile strain of the portion that is subjected to tensile strain retention in a high-temperature oxidation environment. .

〔発明の実施例〕[Embodiments of the invention]

本発明の一実施例を第３図に示す。肉厚ｔは一様である
が、山部３の波形半径ｒ１を谷部のそれｒ２の２．２倍
として、山部３の剛性を高めることにより、山部３に生
じるひずみを谷部４のそれの約１／３となしている。な
お、弾性範囲においては最大ひずみ芝は次式で表わされ
る。An embodiment of the present invention is shown in FIG. Although the wall thickness t is uniform, by increasing the rigidity of the crest 3 by setting the waveform radius r1 of the crest 3 to 2.2 times that of the trough r2, the strain occurring in the crest 3 can be reduced to the trough 4. It is about 1/3 of that of . In addition, in the elastic range, the maximum strain of the grass is expressed by the following formula.

ここに、Ｐは軸力、Ｅは縦弾性係数、Ｒはベローズの平
均半径、ｒは波形の半径、ｔは肉厚で、Ａ。Here, P is the axial force, E is the longitudinal elastic modulus, R is the average radius of the bellows, r is the radius of the corrugation, t is the wall thickness, and A.

Ｂは形状に依存する無次元値である。B is a dimensionless value that depends on the shape.

以上の構成において、ベローズが圧縮変形すると山部３
においては外面に引張り、内面に圧縮ひずみが発生し、
谷部４においては外面に圧縮、内面に引張りひずみが発
生し、その状態が保持される。第１図の従来例において
、これらひずみの値が１％の場合、第２図から、約３０
０回の経返しによって山部３外面に破壊が発生ずること
が予測される。一方、第３図の本発明一実施例の場合は
山部３のひずみが約０．５％、谷部４のそれが約１゜５
％となり、約１　、２００回の繰返しで山部３と谷部４
の外面の両者に破壊が発生すると予測され、従来例に比
して寿命が約４倍となると考えられる。In the above configuration, when the bellows is compressed and deformed, the crest 3
In this case, tensile strain occurs on the outer surface and compressive strain occurs on the inner surface.
In the valley portion 4, compressive strain occurs on the outer surface and tensile strain occurs on the inner surface, and this state is maintained. In the conventional example shown in Fig. 1, if the value of these strains is 1%, from Fig. 2, approximately 30
It is predicted that destruction will occur on the outer surface of the peak portion 3 after 0 repetitions. On the other hand, in the case of the embodiment of the present invention shown in FIG.
%, and after about 1,200 repetitions, the peak 3 and valley 4
It is predicted that breakage will occur on both outer surfaces of the device, and it is thought that the lifespan will be approximately four times longer than that of the conventional example.

第４図に示す他の実施例においては、山部３と谷部４の
波形半径ｒｌｌｒ２は同じであるが、ロール成形あるい
は金型成形により、山部３の肉厚１、を他の１．５倍と
厚くし、山部３に生じるひずみを谷部４のそれの約１／
３となっている。In another embodiment shown in FIG. 4, the waveform radii rllr2 of the peaks 3 and valleys 4 are the same, but the wall thickness 1 of the peaks 3 is changed to another 1.0 by roll forming or die forming. The thickness is increased to 5 times, and the strain generated in the peaks 3 is approximately 1/1 of that in the valleys 4.
It is 3.

なお、高温においてベローズが引張変形を受ける場合や
、ベローズ内側の媒体の段化度が外側のそれよりも大で
ある場合は谷部のたわみ剛性を山部よりも大きくし、第
２１９１に示ず椋１１Ｕによる強度低下度が図と異なる
場合は山部と谷部がほぼ同一の寿命を示すように両者の
たわみ剛性の比を最適化することはもちろんである。In addition, when the bellows undergoes tensile deformation at high temperatures, or when the degree of gradation of the medium inside the bellows is greater than that on the outside, the flexural rigidity of the troughs should be made larger than that of the crests, and the bending stiffness as shown in No. 2191 shall not be applied. If the degree of strength reduction due to the plow 11U is different from that shown in the diagram, it goes without saying that the ratio of the flexural rigidity of the peaks and valleys should be optimized so that they have approximately the same lifespan.

〔発明の効果〕〔Effect of the invention〕

以上のように、本発明によれば、高温酸化環境中で引張
ひすみ保持を受ける部分のノα大引ｉ；にひずみを小さ
くできるから、ベローズの同温疲労寿命が大となる効果
がある。As described above, according to the present invention, it is possible to reduce the strain in the part subjected to tensile strain retention in a high-temperature oxidation environment, which has the effect of increasing the isothermal fatigue life of the bellows. .

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は従来例の断面図、第２図は高温疲労強度に及ぼ
す環境効果を示す説明図、第３図は本発明一実施例の断
面図、第４図は本発明の池の実施例の断面図である。 ■・・・外部媒体、２・・・内部媒体、３・・・山部、
４・・・谷部、ｒｌｌｒｌ＋・・・山部及び谷部の波形
半径、ｔ・・・芽　２　閃 第３　良Fig. 1 is a sectional view of a conventional example, Fig. 2 is an explanatory diagram showing environmental effects on high temperature fatigue strength, Fig. 3 is a sectional view of an embodiment of the present invention, and Fig. 4 is an embodiment of a pond of the present invention. FIG. ■...External medium, 2...Internal medium, 3...Yamabe,
4...Trough, rllrl+...Wave radius of peak and valley, t...bud 2 flash 3 good

Claims (1)

【特許請求の範囲】[Claims] １、内外媒体に対する引張ひすみ保持の高温疲労強度が
異なる材料からなり、高温において長時間の一方向変位
保持を繰返す変形吸収ベローズにおいて、山部と谷部の
たわみ剛性を異ならせ、しかして、高温の変形保持時に
、引張ひすみ保持の疲労強度が低くなる媒体側の最大引
張ひずみを他のそれよりも小さくしたことを特徴とする
変形吸収ベローズ。1. In a deformation-absorbing bellows that is made of materials with different high-temperature fatigue strengths for maintaining tensile strain with respect to the internal and external media and that repeatedly maintains unidirectional displacement for a long time at high temperatures, the flexural rigidity of the peaks and valleys is made different, and A deformation-absorbing bellows characterized in that the maximum tensile strain on the medium side, at which the fatigue strength of maintaining tensile strain decreases during deformation retention at high temperatures, is smaller than that of other materials.