JP4170784B2

JP4170784B2 - Steam valve and method of manufacturing steam valve

Info

Publication number: JP4170784B2
Application number: JP2003018946A
Authority: JP
Inventors: 優宮内; 晋司渡邉; 竜平竹丸; 和人篠田; 祐一河野; 大樹本谷; 蔵進藤
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2003-01-28
Filing date: 2003-01-28
Publication date: 2008-10-22
Anticipated expiration: 2023-01-28
Also published as: JP2004232484A

Description

【０００１】
【発明の属する技術分野】
本発明は、蒸気タービンの主蒸気管や再熱蒸気管の高温高圧蒸気の流量制御に適用可能な蒸気弁および蒸気弁の製造方法に関する。
【０００２】
【従来の技術】
１９６０年代後半に、蒸気圧力２４．１ＭＰａ、蒸気温度５３８／５６６℃の一段再熱の蒸気条件がわが国の事業用火力タービンの標準的なものとして確立されてからは、最近に至るまで事業用火力タービンの画期的な進展はみられなかった。しかし、オイルショック以来、省エネルギー化が強力に推進され、また、その後の地球温暖化問題に対する急速な関心の高まりから火力発電プラントの高効率化が押し進められている。
【０００３】
火力発電プラントにおいて熱効率を上げるためには、蒸気タービンに流入する蒸気の高温化および高圧化が最も有効な手段であり、現在、蒸気圧力３５ＭＰａ、蒸気温度６５０℃以上の蒸気条件の採用が検討されている。
【０００４】
図２６は、従来の蒸気弁２００の断面図を示す。この蒸気弁２００は、弁本体２０１に上蓋２０２をボルト２０３にて固定して構成される圧力容器部２０４と、弁棒２０５が取り付けられた主弁２０６、弁棒２０５を摺動可能に支持する案内片２０７、蒸気中の異物を捕捉するストレーナ２０８および弁本体２０１に固着した弁座２０９から構成される蒸気通路部２１０とから構成されている。
【０００５】
弁棒２０５は、ブランケット２１１を介してボルト２１２により弁本体２０１に固定されたアクチュエータ（図示しない）によって、上下方向に作動させられる。また、案内片２０７は、ボルト２１３によりブランケット２１１に固定されている。
【０００６】
蒸気は、蒸気弁２００の蒸気流入孔２１４から流入し、主弁２０６と弁座２０９の間に形成される流路を通過して、蒸気流出孔２１５から流出する。
【０００７】
従来の蒸気弁２００の弁本体２０１の材料として、クロム、モリブデンを添加することにより高温強度を増し、さらにこれらの添加物による材料表面の不安定現象を抑えるためにバナジウムを添加したクロム−モリブデン−バナジウム鋳鋼材が広く使用されていた。また、従来の弁本体２０１は、図１９に示すように、複雑な形状を有しているので、鋳造による製造が最適の方法とされていた（例えば、特許文献１参照。）。
【０００８】
【特許文献１】
特公平７−５４０８９号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、従来の弁本体は、複雑な形状であるために、構造上各部分の肉厚が不均一となり、蒸気タービンの起動時などにおいて、厚肉部の内外面の間の温度差による多大な熱応力が発生するという問題があった。
【００１０】
また、火力発電プラントにおける熱効率の向上のため、蒸気弁に作用する蒸気圧力や蒸気温度を上昇させようとすると、さらに大きな熱応力が発生するという問題があった。
【００１１】
さらに、現在の火力発電プラントにおいて使用されている各種材料の使用限界温度は６００℃程度であるが、火力発電プラントにおける熱効率の向上のため、近い将来さらに、蒸気の高温化および高圧化が進められるのは明らかである。そこで、蒸気の高温化および高圧化に対応することができる蒸気弁の開発が求められている。
【００１２】
そこで本発明は、高温化および高圧化された蒸気条件においても、熱応力を緩和することができ、蒸気弁の信頼性を維持することができる蒸気弁および蒸気弁の製造方法を提供することを目的とする。
【００１３】
【課題を解決するための手段】
上記目的を達成するために、本発明の蒸気弁は、蒸気の流入孔が穿設され、球状の弁室を有する第１の弁本体と、前記流入孔の周囲に形成された第１の補強部と、前記流入孔に連通するように前記第１の弁本体に溶着された蒸気流入部と、前記第１の弁本体と連通し、蒸気の流出孔が穿設され、球状の弁室を有する第２の弁本体と、前記流出孔の周囲に形成された第２の補強部と、前記流出孔に連通するように前記第２の弁本体に溶着された蒸気流出部とを具備し、前記第１の弁本体および前記第２の弁本体の内外面、並びに前記第１の補強部および前記第２の補強部が機械加工によって形成され、かつ前記第１の弁本体、前記第２の弁本体、前記第１の補強部および前記第２の補強部が一体的に形成されたことを特徴とする。
【００１４】
この蒸気弁によれば、第１の弁本体および第２の弁本体の形状を球状とし、補強部を設けることで、弁本体全体の肉厚を薄く構成することができ、重量を軽減、製作コストの削減を図ることができる。
【００１５】
また、第１の弁本体および第２の弁本体の形状を球状とすることで、発生する熱応力そのものの絶対値を低く抑えることができる。さらに、球状で構成される第１の弁本体および第２の弁本体は、機械加工で製作されるため、壁部の肉厚を均一かつ薄肉化することができるので、蒸気タービン起動時等の熱応力を緩和することができる。これによって、蒸気弁の信頼性を向上させることができる。また、高温化および高圧化された蒸気条件においても、熱応力を緩和することができ、蒸気弁の信頼性を維持することができる。
【００１６】
また、本発明の蒸気弁は、蒸気の流入孔が穿設され、球状の弁室を有する弁本体と、
前記流入孔の周囲に形成された補強部と、前記流入孔に連通するように前記弁本体に溶着された蒸気流入部と、前記弁本体の外形を形成する際の機械加工の中心軸に沿って形成された蒸気流出部とを具備し、前記弁本体の内外面、前記補強部および前記蒸気流出部が機械加工によって形成され、かつ一体的に形成されたことを特徴とする。
【００１７】
この蒸気弁によれば、弁本体の形状を簡素化し、弁本体自体の全長を短くすることができ、重量を軽減、製作コストの削減を図ることができる。
【００１８】
また、蒸気出口管は、機械加工によって弁本体と一体化して製作されるため、弁本体では、熱応力が集中しやすい蒸気出口管の構造溶接部が存在しない。これによって、弁本体における熱応力の集中を回避することができるので、蒸気弁としての品質を格段に向上させることができる。
【００１９】
本発明の蒸気弁の製造方法は、蒸気弁の弁本体を形成する弁本体製造過程と、前記弁本体製造過程において形成された弁本体に蒸気流入部および蒸気流出部を形成する蒸気流入出部製造過程とを備えた蒸気弁の製造方法であって、前記弁本体製造過程が、第１の軸を機械加工の中心軸として、素材を機械加工により、前記第１の軸を回転軸とした回転体形状である、２つの球体が連結した形状に切削する外形形成工程と、前記外形形成工程によって外周が機械加工により切削された前記素材に、前記第１の軸を中心軸として貫通孔を機械加工により形成する貫通孔形成工程と、前記第１の軸と直交し、前記外形形成工程で形成された前記２つの球体のうち一方の球体の中心を通る第２の軸を中心軸として、該一方の球体に第１の凹部を機械加工により切削する第１の凹部形成工程と、前記第１の凹部形成工程によって形成された凹部を有する前記一方の球体の内部を、前記第２の軸を中心軸として機械加工により切削し、ほぼ球状の空間を形成し、かつ、前記第１の凹部の開口部の周囲に補強部を形成する第１の空間形成工程と、前記第１の軸と直交し、前記外形形成工程で形成された前記２つの球体のうち他方の球体の中心を通る第３の軸を中心軸として、該他方の球体に第２の凹部を機械加工により切削する第２の凹部形成工程と、前記第２の凹部形成工程によって形成された凹部を有する前記他方の球体の内部を、前記第３の軸を中心軸として機械加工により切削し、ほぼ球状の空間を形成し、かつ、前記第２の凹部の開口部の周囲に補強部を形成する第２の空間形成工程とを備え、前記蒸気流入出部製造過程が、前記第１の凹部形成工程によって形成された開口部に連通するように前記一方の球体に蒸気流入部を溶着する蒸気流入部溶着工程と、前記第２の凹部形成工程によって形成された開口部に連通するように前記他方の球体に蒸気流出部を溶着する蒸気流出部溶着工程とを備えることを特徴とする。
【００２０】
この蒸気弁の製造方法によれば、蒸気弁の外周面の機械加工の中心軸と内周面の機械加工の中心軸とを別個に設定し、蒸気弁の外周面および内周面を別個に切削することで、第１および第２の凹部の開口部の周囲に補強部を形成することができる。
【００２１】
また、蒸気弁を形成する弁室の形状を球状とし、補強部を設けることで、弁本体全体の肉厚を薄く構成することができ、重量の軽減、製作コストの削減を図ることができる。
【００２２】
また、蒸気弁を形成する弁室を球状とすることで、発生する熱応力そのものの絶対値を低く抑えることができる。さらに、弁本体は、機械加工で製作されるため、壁部の肉厚を均一かつ薄肉化することができるので、蒸気タービン起動時等の熱応力を緩和することができる。これによって、蒸気弁の信頼性を向上させることができる。また、高温化および高圧化された蒸気条件においても、熱応力を緩和することができ、蒸気弁の信頼性を維持することができる。
【００２３】
また、本発明の蒸気弁の製造方法は、蒸気弁の弁本体を形成する弁本体製造過程と、前記弁本体製造過程において形成された弁本体に蒸気流入部を形成する蒸気流入部製造過程とを備えた蒸気弁の製造方法であって、前記弁本体形成過程が、第１の軸を機械加工の中心軸として、素材を機械加工により、前記第１の軸を回転軸とした回転体形状である球体形状に切削する外形形成工程と、前記外形形成工程によって、外周が機械加工により切削された前記素材に、前記第１の軸を中心軸として貫通孔を機械加工により形成する貫通孔形成工程と、前記第１の軸と直交し、前記外形形成工程で形成された前記球体の中心を通る第２の軸を中心軸として、前記球体に凹部を機械加工により切削する凹部形成工程と、前記凹部形成工程によって形成された凹部を有する前記球体の内部を、前記第２の軸を中心軸として機械加工により切削し、ほぼ球状の空間を形成し、かつ、前記凹部の開口部の周囲に補強部を形成する空間形成工程とを備え、前記蒸気流入部製造過程が、前記凹部形成工程によって形成された開口部に連通するように前記球体に蒸気流入部を溶着する蒸気流入部溶着工程を備えることを特徴とする。
【００２４】
この蒸気弁の製造方法によれば、蒸気弁の弁本体の形状を簡素化し、弁本体自体の全長を短くすることができ、重量の軽減、製作コストの削減を図ることができる。
【００２５】
また、蒸気出口管は、機械加工によって弁本体と一体化して製作されるため、弁本体では、熱応力の集中しやすい蒸気出口管の構造溶接部が存在しない。これによって、弁本体における熱応力の集中を回避することができるので、蒸気弁としての品質を格段に向上させることができる。
【００２６】
【発明の実施の形態】
以下、図面を参照して本発明の実施の形態について説明する。
【００２７】
（第１の実施の形態）
本発明の第１の実施の形態の蒸気弁１の概要を図１を参照して説明する。図１は、第１の実施の形態の蒸気弁１の断面図を示す。図２は、蒸気弁１の弁本体２の断面図を示す。
【００２８】
第１の実施の形態の蒸気弁１は、弁本体２、上蓋３、主弁４、弁棒５、案内片６、弁座７、ストレーナ８、ブラケット９で主に構成されている。
【００２９】
弁本体２は、蒸気流入側弁本体２ａと蒸気流出側弁本体２ｂとから構成される。蒸気流入側弁本体２ａの上部の開口部には、上蓋３がボルト１０にて固定されている。また、蒸気流入側弁本体２ａと蒸気流出側弁本体２ｂとの連通部には、弁座７が固着され、その弁座７と上蓋３との間に蒸気中の異物を捕捉するストレーナ８が設置されている。
【００３０】
主弁４に取り付けられた弁棒５は、案内片６に摺動可能に支持され、ブラケット９を介してボルト１０により蒸気流出側弁本体２ｂに固定されたアクチュエータ（図示しない）によって、上下方向に作動させられる。
【００３１】
蒸気は、蒸気流入側弁本体２ａに開口された蒸気流入孔１１から流入し、主弁４と弁座７の間に形成される流路を通過して、蒸気流出側弁本体２ｂに開口された蒸気流出孔１２から流出する。また、蒸気流入孔１１には蒸気流入管１３が、蒸気流出孔１２には蒸気流出管１４が接続されている。
【００３２】
さらに、蒸気流入側弁本体２ａの内壁の蒸気流入孔１１の周囲には、補強のために補強余肉部１５が設けられている。また、蒸気流入側弁本体２ａの内壁と同様に、蒸気流出側弁本体２ｂの内壁の蒸気流出孔１２の周囲には、補強のために補強余肉部１５が施されている。ここで、補強余肉部１５とは、例えば、蒸気流入側弁本体２ａ側で示すと、蒸気流入側弁本体２ａに蒸気流入孔１１を設けるために蒸気流入側弁本体２ａから取り除かれた体積に相当する蒸気流入側弁本体２ａの構成部材を所定の範囲に補った部分をいう。なお、補強余肉部１５の算出方法などについては、後述する。
【００３３】
なお、補強余肉部１５は、蒸気流入側弁本体２ａや蒸気流出側弁本体２ｂの内壁に形成されることに限らず、蒸気流入側弁本体２ａおよび蒸気流出側弁本体２ｂの外壁に形成されてもよい。
【００３４】
本発明においては、主に蒸気弁１の弁本体２の構成および製造方法を特徴としているので、以下には、主に弁本体２について図２を参照して説明する。
【００３５】
弁本体２の素材は、例えば、大型鋼塊の製造性に優れ高温強度に優れたコバルト基合金鋼などで構成され、鍛造によって形成される。ここで用いられるコバルト基合金鋼は、例えば、コバルトを重量割合で５０％以上含むものなどである。
【００３６】
鍛造部材は、内在欠陥がなく、鋳造部材に比べ鋳造係数等の設計時に考慮すべき許容応力上の余裕を取る必要がないため、薄肉の弁本体２を形成することができる。弁本体２を薄肉で形成することで、熱応力の発生を緩和することができる。しかし、鍛造にて製作したとしても、造形寸法によってはその効果を十分に得ることが困難な場合があるため、本発明の弁本体２は、各部分の肉厚を精度よく仕上げるために、弁本体２の内外面ともに機械加工で製作された。
【００３７】
図２に示した弁本体２は、上述したように、蒸気流入側弁本体２ａと蒸気流出側弁本体２ｂから構成され、弁本体２は、１つの素材から機械加工によって形成される。また、弁本体２は、内外面の全面を機械加工できるように形状の簡素化が図られている。さらに、より蒸気タービン起動時などの熱応力を緩和するために、極力薄肉とするための手段として、弁本体２の最大熱応力が発生する部分に球面体形状を採用し、発生する熱応力そのものの絶対値を低く抑える構造にしている。
【００３８】
また、蒸気流入側弁本体２ａには、蒸気流入孔１１が開口され、蒸気流出側弁本体２ｂには、蒸気流出孔１２が開口されている。弁本体２は、圧力容器でもあり、圧力容器とした場合、弁本体２の胴部に蒸気流入孔１１および蒸気流出孔１２の貫通穴が開口されているため、強度上不十分となる。そこで、弁本体２では、第一種圧力容器構造規格に基づいて、補強余肉部１５が設けられている。
【００３９】
ここで、補強余肉部１５は、弁本体２の胴部に開口された蒸気流入孔１１および蒸気流出孔１２により、これらの付近の構造上の強度が低下するのを避けるための補強部として、蒸気流入孔１１および蒸気流出孔１２の開口部付近に形成される。この補強余肉部１５の最小断面積（Ａ）は、次の式によって求めることができる。
【００４０】
Ａ＝Ｆ×ｔ_ｒ×ｄ … 式（１）
ここで、ｄは腐食代を除いた穴の最大径、ｔ_ｒは穴のない弁本体２の胴部の計算上必要な厚さ、Fは係数であり、ここでは１とする。
【００４１】
図３に、式（１）に基づいて算出した最小断面積で、補強を行った弁本体２０と、弁本体２０の開口部２２に接続された配管２１の断面図の一例を示す。補強余肉部である斜線部Ｂの合計の面積が、式（１）で算出された斜線部Ａの面積と等しくなっている。
【００４２】
このように、最小断面積で蒸気流入孔１１および蒸気流出孔１２の開口部付近を補強することで、弁本体２の全体の肉厚を薄くすることができ、製品としてバランスが取れた形状となり、蒸気弁１の総重量および製作コストをともに最小限に抑えることができる。
【００４３】
（弁本体２の製作方法）
次に、図４乃至１１を参照して、弁本体２の製作方法の一例を説明する。なお、図４乃至１１は、弁本体２の各製作工程における断面図を示している。また、ここでは、弁本体２は、例えば、ＮＣ複合立旋盤などの工作機器を用いて機械加工によって製作される。
【００４４】
図４に示すように、例えば、円柱などの形状をした素材３０のＹ−Ｙ軸を機械加工の中心軸として、素材３０を切削し、２つの球体が連結した形状の部分とその２つの球体のＹ−Ｙ軸方向の両端に円筒部を有する弁本体２の外形を形成する（図５）。
【００４５】
弁本体２の外形が形成された素材３０の中央に、Ｙ−Ｙ軸に沿って貫通孔３１を形成する（図６）。なお、貫通孔３１の径は、ブラケット９によって閉じられる蒸気流出側弁本体２ｂの下部に形成された開口部の径とほぼ等しくしておくことが好ましい。
【００４６】
さらに、蒸気流出側弁本体２ｂに設置される案内片６の固定部、蒸気流入側弁本体２ａと蒸気流出側弁本体２ｂとの連通部に設置される弁座７の固定部および蒸気流出側弁本体２ｂに設置される上蓋３の固定部における径に対応する径で、貫通孔３１をさらに切削する（図７）。
【００４７】
続いて、素材３０は、蒸気流入側弁本体２ａの蒸気流入孔１１を形成するために、Ｙ−Ｙ軸と直交し、蒸気流入側弁本体２ａの中心を通るＸＡ−ＸＡ軸を機械加工の中心軸として、ＸＡ−ＸＡ軸に沿って切削される。そして、その切削は、対向する側に蒸気流入側弁本体２ａの壁部の厚さを残して停止され、その切削によって凹部が形成される（図８）。
【００４８】
また、素材３０は、蒸気流出側弁本体２ｂの蒸気流出孔１２を形成するために、Ｙ−Ｙ軸と直交し、蒸気流出側弁本体２ｂの中心を通るＸＢ−ＸＢ軸を機械加工の中心軸として、ＸＢ−ＸＢ軸に沿って切削される。そして、その切削は、対向する側に蒸気流出側弁本体２ｂの壁部の厚さを残して停止され、その切削によって凹部が形成される（図８）。
【００４９】
次に、ＸＡ−ＸＡ軸を機械加工の中心軸として、素材３０の内部が切削され、ほぼ球状の内壁が形成される（図９）。なお、図９に示すように、蒸気流入孔１１側の内壁部においては、補強余肉部１５を残して切削が行われる。
【００５０】
続いて、ＸＢ−ＸＢ軸を機械加工の中心軸として、素材３０の内部が切削され、ほぼ球状の内壁が形成される（図１０）。なお、図１０に示すように、蒸気流出孔１２側の内壁部においては、補強余肉部１５を残して切削が行われる。図１０に示した工程で、蒸気流入側弁本体２ａおよび蒸気流出側弁本体２ｂから構成される弁本体２が完成する。
【００５１】
次に、蒸気流入側弁本体２ａの蒸気流入孔１１に連通するように、蒸気流入管１３が溶接される。また、蒸気流出側弁本体２ｂの蒸気流出孔１２に連通するように、蒸気流出管１４が溶接される（図１１）。
【００５２】
第１の実施の形態の蒸気弁１によれば、蒸気弁１の外周面の機械加工の中心軸と内周面の機械加工の中心軸とを別個に設定し、蒸気弁１の外周面および内周面を別個に切削することで、内周面の蒸気流入孔１１および蒸気流出孔１２の付近に、計算上必要となる補強余肉部１５を形成することができる。
【００５３】
また、蒸気流入側弁本体２ａおよび蒸気流出側弁本体２ｂの形状を球体とし、補強余肉部１５を設けることで、弁本体２全体の肉厚を薄く構成することができ、重量を軽減、製作コストの削減を図ることができる。
【００５４】
また、蒸気流入側弁本体２ａおよび蒸気流出側弁本体２ｂの形状を球状とすることで、発生する応力そのものの絶対値を低く抑えることができる。
【００５５】
さらに、球状で構成される蒸気流入側弁本体２ａおよび蒸気流出側弁本体２ｂは、機械加工で製作されるため、壁部の肉厚を均一かつ薄肉化することができるので、蒸気タービン起動時等の熱応力を緩和することができる。これによって、蒸気弁の信頼性を向上させることができるとともに、経年的な保守点検を容易に行うことができる。また、高温化および高圧化された蒸気条件においても、熱応力を緩和することができ、蒸気弁の信頼性を維持することができる。
【００５６】
第１の実施の形態の蒸気弁１の弁本体２における蒸気流入孔１１は、図１２に示すように、蒸気流入側弁本体４０ａと一体化された開先部４１を有する短管部４２によって構成されてもよい。また、ＸＡ−ＸＡ軸を機械加工の中心軸として、補強余肉部１５および短管部４２の開先部４１が形成される。そして、短管部４２の開先部４１に蒸気流入管１３が溶接される。
【００５７】
また、図１２には、蒸気流出側弁本体側について図示されていないが、蒸気流入側弁本体２ａと同様に、蒸気流出孔１２が形成される。
このように蒸気流入側弁本体２ａと一体化された開先部４１を有する短管部４２によって蒸気流入孔１１を構成することで、短管部４２の開先部４１と蒸気流入管１３との溶接部の肉厚が平坦となり、非破壊検査を容易に行うことができる。
【００５８】
また、図１３に示すように、蒸気流入管１３および蒸気流出管１４を異径管で構成し、その異径管の径の大きい側を弁本体２に溶接するようにしてもよい。この場合、蒸気流入孔１１および蒸気流出孔１２の孔径を、図２に示した弁本体２の蒸気流入孔１１および蒸気流出孔１２の孔径よりも大きく開口することができるので、ＸＡ−ＸＡ軸およびＸＢ−ＸＢ軸を中心軸として行う機械加工が容易になり、生産性の向上を図ることができる。
【００５９】
さらに、図２に示された弁本体２では、蒸気流入側弁本体２ａの球状の内壁面および外壁面は、同一中心点に基づいて構成されているが、図１４に示すように、それぞれの中心点を異にして構成されてもよい。
【００６０】
図１４に示された蒸気流入側弁本体２ａでは、内壁面の中心点は、ＸＡ−ＸＡ軸上で、外壁面の中心点よりも蒸気流入孔１１側に位置している。このように、内壁面の中心点を蒸気流入孔１１側に所定の距離ずらすことで、ストレーナ（図示しない）の外周と蒸気流入側弁本体２ａの内壁面との間の蒸気流路を均等に構成することができる。なお、蒸気流出側弁本体２ｂにおいても、蒸気流入側弁本体２ａと同様に、球状の内壁面および外壁面の中心点を異にして構成することもできる。
【００６１】
これまで示した実施の形態の弁本体では、補強余肉部１５は、例えば、図２に示すように、ＸＡ−ＸＡ軸またはＸＢ−ＸＢ軸に対して垂直方向に平面形状の内周面を有して形成されているが、この形状に限るものではない。例えば、図１５に示すように、蒸気流入側弁本体２ａの球状の内壁の半径を、蒸気流入孔１１側に向けて徐々に減少させ、内壁の蒸気流入孔１１側に補強余肉部１５を形成することもできる。これと同様に、蒸気流出側弁本体２ｂの球状の内壁の半径を、蒸気流出孔１２側に向けて徐々に減少させ、内壁の蒸気流出孔１２側に補強余肉部１５を形成することもできる。
【００６２】
ここで使用した弁本体２の素材は、内在欠陥のない鍛造部材であるが、今後の精密な鋳造技術と新規材料開発の進歩にともない、前述の鍛造部材と同等品質の鋳造部材が得られるようになれば、鍛造部材に限らず、鋳造部材も弁本体２を形成する素材として用いることができる。この場合にも、前述した鍛造部材を用いて弁本体２を製作する場合と同様の効果を得ることができる。
【００６３】
また、図４乃至１１に弁本体２の製作方法の一例を説明したが、弁本体２の製作方法はこれに限られるものではなく、機械加工によって弁本体２の形状が製作されるものならばよい。
【００６４】
（第２の実施の形態）
本発明の第２の実施の形態の蒸気弁の弁本体５０の概要を図１６および１７を参照して説明する。図１６は、第２の実施の形態の弁本体５０の断面図を示す。図１７は、蒸気流入管５１の斜視図を示す。
【００６５】
図１６に示された弁本体５０は、蒸気流入側弁本体５０ａと蒸気流出側弁本体５０ｂから構成され、弁本体５０は、１つの素材から機械加工によって形成される。また、弁本体５０は、内外面の全面を機械加工できるように形状の簡素化が図られている。さらに、より蒸気タービン起動時などの熱応力を緩和するために、極力薄肉とするための手段として、弁本体５０の最大熱応力が発生する部分に球面体形状を採用し、発生する熱応力そのものの絶対値を低く抑える構造にしている。
【００６６】
また、蒸気流入側弁本体５０ａには、蒸気流入管５１を溶接するための開先部５２を有する開口部が、蒸気流入側弁本体５０ａの球状の内壁の中心点ＯａからＸＡ−ＸＡ軸に対称に角度αに対応して形成される。角度αは、γ×２およびδ×２のうちいずれか小さい方の角度を最大角とし、角度αは、その最大角以下の角度で構成される。ここで、角度γは、上蓋３が固定される面５４に対して垂直な蒸気流入側弁本体５０ａの円筒部の外壁５５と蒸気流入側弁本体５０ａの球状の外壁とが交わる点Ｐと中心点Ｏａとを結んだ直線と、ＸＡ−ＸＡ軸とによって形成される角度である。また、角度δは、蒸気流入側弁本体５０ａと蒸気流出側弁本体５０ｂとの外壁が交わる点Ｑと中心点Ｏａとを結んだ直線と、ＸＡ−ＸＡ軸とによって形成される角度である。
【００６７】
また、蒸気流入側弁本体５０ａと同様に、蒸気流出側弁本体５０ｂには、蒸気流出管５３を溶接するための開先部５２を有する開口部が、蒸気流出側弁本体５０ｂの球状の内壁の中心点ＯｂからＸＢ−ＸＢ軸に対称に角度βに対応して形成される。角度βは、θ×２およびφ×２のうちいずれか小さい方の角度を最大角とし、角度βは、その最大角以下の角度で構成される。ここで、角度θは、ブラケット９が固定される面５６に対して垂直な蒸気流出側弁本体５０ｂの円筒部の外壁５７と蒸気流出側弁本体５０ｂの球状の外壁とが交わる点Ｒと中心点Ｏｂとを結んだ直線と、ＸＢ−ＸＢ軸とによって形成される角度である。また、角度φは、蒸気流入側弁本体５０ａと蒸気流出側弁本体５０ｂとの外壁が交わる点Ｓと中心点Ｏｂとを結んだ直線と、ＸＢ−ＸＢ軸とによって形成される角度である。
【００６８】
第２の実施の形態の弁本体５０の蒸気流入側弁本体５０ａおよび蒸気流出側弁本体５０ｂの開口部の径は、第１の実施の形態の弁本体２の蒸気流入側弁本体２ａの蒸気流入孔１１および蒸気流出側弁本体２ｂの蒸気流出孔１２の径よりも十分に大きく形成することができるので、作業効率を向上することができる。また、蒸気流入側弁本体５０ａおよび蒸気流出側弁本体５０ｂでは、開口部の径が十分に大きいので、補強余肉部５８を弁本体５０の任意な部分に形成することが容易になり、最適な弁本体５０の補強を行うことができる。
【００６９】
蒸気流入管５１は、１つの素材から機械加工によって形成され、内外面の全面を機械加工できるように形状の簡素化が図られている。また、蒸気流入管５１は、蒸気流入側弁本体５０ａの球状の壁部の一部を有して形成されている。
【００７０】
蒸気流入側弁本体５０ａの開口部の開先部５２の面と対向する蒸気流入管５１のテーパ部５１ａは、ＸＡ−ＸＡ軸を中心軸としてほぼ角度αの角度を有している。また、テーパ部５１ａは、蒸気流入側弁本体５０ａの開口部と最適に溶接されるように開先部を有している。さらに、図１６に示すように、蒸気流入管５１は、補強余肉部５８を一体化して機械加工によって形成されている。そして、蒸気流入管５１は、蒸気流入側弁本体５０ａの開口部に溶接される。
【００７１】
蒸気流出管５３は、蒸気流入管５１と同様に、１つの素材から機械加工によって形成され、内外面の全面を機械加工できるように形状の簡素化が図られている。また、蒸気流出管５３は、蒸気流出側弁本体５０ｂの球状の壁部の一部を有して形成されている。
【００７２】
図１６に示すように、蒸気流出側弁本体５０ｂの開口部の開先部５２の面と対向する蒸気流出管５３のテーパ部５３ａは、ＸＢ−ＸＢ軸を中心軸としてほぼ角度βの角度を有している。また、テーパ部５３ａは、蒸気流出側弁本体５０ｂの開口部と最適に溶接されるように開先部を有している。さらに、蒸気流出管５３は、補強余肉部５８を一体化して機械加工によって形成されている。そして、蒸気流出管５３は、蒸気流出側弁本体５０ｂの開口部に溶接される。
【００７３】
弁本体５０、蒸気流入管５１および蒸気流出管５３は、それぞれ別個に機械加工によって製作されるので、例えば、弁本体５０を大型鋼塊の製造性に優れ高温強度に優れたコバルトを重量割合で５０％以上含むコバルト基合金鋼で製作し、蒸気流入管５１および蒸気流出管５３を高温強度に優れたニッケルを重量割合で３５％以上含むニッケル基合金鋼で製作することもできる。また、例えば、弁本体５０を鋳造部材で製作し、蒸気流入管５１および蒸気流出管５３を鍛造部材で製作することもできる。
【００７４】
なお、弁本体５０は、基本的には第１の実施の形態で説明した弁本体２の製作工程と同様の工程で製作される。
【００７５】
このように、構成部品の発生応力（要求強度）に応じて、材料または材料の製造方式を選択して材料を使用することで、最適な蒸気弁を製作することができる。
【００７６】
第２の実施の形態の蒸気弁によれば、蒸気流入管５１および蒸気流出管５３は、弁本体５０の球状の壁部を開口して溶接されるため、壁部の開口径を大きくとることができ、弁本体５０の内部の機械加工が容易になり、生産性の向上を図ることができる。
【００７７】
また、蒸気流入管５１および蒸気流出管５３は、弁本体５０とは別個に、機械加工により補強余肉部５８を一体化して形成されるので、補強余肉部５８の形成が容易で、生産性の向上を図ることができる。さらに、補強余肉部５８の形状を用途に合わせて任意に形成できるので、より的確な補強部を形成することができる。また、蒸気流入側弁本体５０ａおよび蒸気流出側弁本体５０ｂの形状を球体とし、補強余肉部５８を設けることで、弁本体５０全体の肉厚を薄く構成することができ、重量を軽減、製作コストの削減を図ることができる。
【００７８】
さらに、蒸気流入側弁本体５０ａの開口部、蒸気流出側弁本体５０ｂの開口部、蒸気流入管５１のテーパ部５１ａおよび蒸気流出管５３のテーパ部５３ａに開先部を機械加工によって正確に形成することができるので、最適な溶接を行うことができ、溶接部の品質を向上させることができる。
【００７９】
また、球状の蒸気流入側弁本体５０ａおよび蒸気流出側弁本体５０ｂの壁部に開口し、球状部で蒸気流入管５１および蒸気流出管５３が構造溶接されるため、直接的に応力集中の発生する部位を回避することができる。これによって、蒸気流入管５１および蒸気流出管５３の溶接部の品質を格段に向上させることができる。
【００８０】
（第３の実施の形態）
本発明の第３の実施の形態の蒸気弁６０の概要を図１８を参照して説明する。図１８は、第３の実施の形態の蒸気弁６０の断面図を示す。
【００８１】
第３の実施の形態の蒸気弁６０の弁本体６１は、図１に示す第１の実施の形態の蒸気弁１の蒸気流入側弁本体２ａ側のみを用いた構成となっている。
【００８２】
第３の実施の形態の蒸気弁６０は、弁本体６１、上蓋６２、主弁６３、弁棒６４、弁座６５、ストレーナ６６で主に構成されている。
【００８３】
機械加工によって製作された弁本体６１には、蒸気流入孔６８、上部開口部６９および蒸気流出孔７０が開口され、蒸気流入孔６８には、蒸気流入管７１が溶接されている。また、弁本体６１の球状の内壁の蒸気流入孔６８側には、補強余肉部７２が設けられている。
【００８４】
弁本体６１の上部開口部６９には、上蓋６２がボルト６７にて固定されている。また、蒸気弁６０の中心軸であるＹ−Ｙ軸に沿って、上蓋６２に弁棒６４の案内孔が開口されている。弁棒６４の一端には主弁６３が接続され、弁棒６４のＹ−Ｙ軸方向の移動によって、主弁６３と弁座６５との間に形成される蒸気流路の開閉を行う。弁棒６４のＹ−Ｙ軸方向の移動は、アクチュエータなど（図示しない）によって行われる。また、弁座６５と上蓋６２との間に蒸気中の異物を捕捉するストレーナ６６が設置されている。
【００８５】
蒸気は、弁本体６１に開口された蒸気流入孔６８から流入し、主弁６３と弁座６５の間に形成される蒸気流路を通過して、蒸気流出孔７０から流出する。
【００８６】
弁本体６１および蒸気流入管７１は、例えば、高温域で高強度であり小型鋼塊の製造が容易なニッケルを重量割合で３５％以上含むニッケル基合金鋼などで形成されるが、これに限られるものではない。
【００８７】
（弁本体６１の製作方法）
次に、図１９乃至２５を参照して、弁本体６１の製作方法の一例を説明する。なお、図１９乃至２５は、弁本体６１の各製作工程における断面図を示している。また、ここでは、弁本体６１は、例えば、ＮＣ複合立旋盤などの工作機器を用いて機械加工によって製作される。
【００８８】
図１９に示すように、例えば、円柱などの形状をした素材８０のＹ−Ｙ軸を機械加工の中心軸として、素材８０を切削し、球体部とその球体部のＹ−Ｙ軸方向の両端に円筒部を有する形状の弁本体６１の外形を形成する（図２０）。
【００８９】
弁本体６１の外形が形成された素材８０の中央に、Ｙ−Ｙ軸に沿って貫通孔８１を形成する（図２１）。
【００９０】
さらに、弁座６５の固定部における径に対応する径で、貫通孔８１をさらに切削する（図２２）。
【００９１】
続いて、素材８０は、弁本体６１の蒸気流入孔６８を形成するために、Ｙ−Ｙ軸と直交し、弁本体６１の中心を通るＸＡ−ＸＡ軸を機械加工の中心軸として、ＸＡ−ＸＡ軸に沿って切削される。そして、その切削は、対向する側に弁本体６１の壁部の厚さを残して停止され、その切削によって凹部が形成される（図２３）。
【００９２】
次に、弁本体６１において、ＸＡ−ＸＡ軸を機械加工の中心軸として、弁本体６１の内部が切削され、ほぼ球状の内壁が形成される（図２４）。なお、図２４に示すように、内壁の蒸気流入孔６８側は、補強余肉部８２を残して切削が行われる。図２４に示した工程で、弁本体６１が完成する。
【００９３】
続いて、弁本体６１の蒸気流入孔６８に連通するように、蒸気流入管７１が溶接される（図２５）。
【００９４】
第３の実施の形態の蒸気弁６０によれば、弁本体６１の形状を簡素化し、弁本体６１自体の全長を短くすることができ、重量の軽減、製作コストの削減を図ることができる。
【００９５】
また、蒸気出口管は、機械加工によって弁本体６１と一体化して製作されるため、弁本体６１では、熱応力の集中しやすい蒸気出口管の構造溶接部が存在しない。これによって、弁本体６１における熱応力の集中を回避することができるので、蒸気弁６０としての品質を格段に向上させることができる。
【００９６】
さらに、弁本体６１の形状を球体とし、補強余肉部８２を設けることで、弁本体６１全体の肉厚を薄く構成することができ、重量の軽減、製作コストの削減を図ることができる。
【００９７】
なお、第２の実施の形態の蒸気弁の弁本体５０においても、第３の実施の形態の蒸気弁の弁本体６１のように、全長を短くした構成を採用することができる。
【００９８】
【発明の効果】
本発明の蒸気弁および蒸気弁の製造方法によれば、高温化および高圧化された蒸気条件においても、熱応力を緩和することができ、蒸気弁の信頼性を維持することができる。
【図面の簡単な説明】
【図１】第１の実施の形態の蒸気弁の断面図。
【図２】第１の実施の形態の蒸気弁の弁本体の断面図。
【図３】補強を行った弁本体と、弁本体の開口部に接続された配管の一例を示す断面図。
【図４】弁本体の製作工程を示す断面図。
【図５】弁本体の製作工程を示す断面図。
【図６】弁本体の製作工程を示す断面図。
【図７】弁本体の製作工程を示す断面図。
【図８】弁本体の製作工程を示す断面図。
【図９】弁本体の製作工程を示す断面図。
【図１０】弁本体の製作工程を示す断面図。
【図１１】弁本体の製作工程を示す断面図。
【図１２】蒸気流入側弁本体の構成の一例を示す断面図。
【図１３】弁本体の構成の一例を示す断面図。
【図１４】弁本体の構成の一例を示す断面図。
【図１５】弁本体の構成の一例を示す断面図。
【図１６】第２の実施の形態の弁本体の断面図。
【図１７】蒸気流入管の斜視図。
【図１８】第３の実施の形態の蒸気弁の断面図。
【図１９】弁本体の製作工程を示す断面図。
【図２０】弁本体の製作工程を示す断面図。
【図２１】弁本体の製作工程を示す断面図。
【図２２】弁本体の製作工程を示す断面図。
【図２３】弁本体の製作工程を示す断面図。
【図２４】弁本体の製作工程を示す断面図。
【図２５】弁本体の製作工程を示す断面図。
【図２６】従来の蒸気弁の断面図。
【符号の説明】
１…蒸気弁
２…弁本体
２ａ…蒸気流入側弁本体
２ｂ…蒸気流出側弁本体
３…上蓋
４…主弁
５…弁棒
６…案内片
７…弁座
８…ストレーナ
９…ブラケット
１０…ボルト
１１…蒸気流入孔
１２…蒸気流出孔
１３…蒸気流入管
１４…蒸気流出管
１５…補強余肉部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steam valve applicable to flow control of high-temperature and high-pressure steam in a main steam pipe and a reheat steam pipe of a steam turbine, and a method for manufacturing the steam valve.
[0002]
[Prior art]
In the latter half of the 1960s, the steam conditions for one-stage reheating with a steam pressure of 24.1 MPa and a steam temperature of 538/566 ° C. were established as standard for commercial thermal turbines in Japan. There was no breakthrough in turbines. However, since the oil shock, energy conservation has been strongly promoted, and the subsequent rapid increase in interest in global warming issues has been pushing for higher efficiency in thermal power plants.
[0003]
In order to increase the thermal efficiency in a thermal power plant, the most effective means is to increase the temperature and pressure of the steam flowing into the steam turbine. Currently, the adoption of steam conditions with a steam pressure of 35 MPa and a steam temperature of 650 ° C. or higher is being studied. ing.
[0004]
FIG. 26 shows a cross-sectional view of a conventional steam valve 200. The steam valve 200 slidably supports a pressure vessel portion 204 formed by fixing an upper lid 202 to a valve body 201 with a bolt 203, a main valve 206 to which a valve rod 205 is attached, and a valve rod 205. It comprises a guide piece 207, a strainer 208 that captures foreign matter in the steam, and a steam passage portion 210 that is composed of a valve seat 209 fixed to the valve body 201.
[0005]
The valve stem 205 is operated in the vertical direction by an actuator (not shown) fixed to the valve main body 201 by a bolt 212 via a blanket 211. The guide piece 207 is fixed to the blanket 211 with a bolt 213.
[0006]
The steam flows from the steam inlet hole 214 of the steam valve 200, passes through a flow path formed between the main valve 206 and the valve seat 209, and flows out from the steam outlet hole 215.
[0007]
Chromium-molybdenum added with vanadium to increase the high-temperature strength by adding chromium and molybdenum as the material of the valve body 201 of the conventional steam valve 200 and further to suppress the unstable phenomenon of the material surface due to these additives. Vanadium cast steel was widely used. Further, since the conventional valve body 201 has a complicated shape as shown in FIG. 19, the production by casting has been the optimum method (see, for example, Patent Document 1).
[0008]
[Patent Document 1]
Japanese Patent Publication No. 7-54089
[0009]
[Problems to be solved by the invention]
However, since the conventional valve body has a complicated shape, the thickness of each part is uneven due to the structure, and at the time of startup of the steam turbine, a great deal of temperature difference occurs between the inner and outer surfaces of the thick part. There was a problem that thermal stress was generated.
[0010]
In addition, in order to improve the thermal efficiency in the thermal power plant, there has been a problem that when a steam pressure or a steam temperature acting on the steam valve is increased, a larger thermal stress is generated.
[0011]
Furthermore, the use limit temperature of various materials used in the present thermal power plant is about 600 ° C. However, in order to improve the thermal efficiency in the thermal power plant, the temperature and pressure of the steam will be further increased in the near future. It is clear. Therefore, development of a steam valve that can cope with higher temperature and higher pressure of steam is required.
[0012]
Accordingly, the present invention provides a steam valve and a method for manufacturing a steam valve that can alleviate thermal stress even under high-temperature and high-pressure steam conditions and maintain the reliability of the steam valve. Objective.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, a steam valve according to the present invention includes a first valve main body having a spherical valve chamber having a steam inflow hole and a first reinforcement formed around the inflow hole. A steam inflow portion welded to the first valve main body so as to communicate with the inflow hole, a steam outflow hole formed in the first valve main body, and a spherical valve chamber. A second valve body having a second reinforcing portion formed around the outflow hole, and a steam outflow portion welded to the second valve body so as to communicate with the outflow hole; The first valve body And the inner and outer surfaces of the second valve main body, the first reinforcing portion and the second reinforcing portion are formed by machining, and the first valve main body, the second valve main body, the first The reinforcing portion and the second reinforcing portion are integrally formed It is characterized by that.
[0014]
According to this steam valve, the shape of the first valve body and the second valve body is made spherical, and the reinforcing part is provided, so that the thickness of the entire valve body can be reduced, and the weight is reduced and manufactured. Cost can be reduced.
[0015]
In addition, by making the first valve body and the second valve body spherical, the absolute value of the generated thermal stress itself can be kept low. Furthermore, since the first valve body and the second valve body configured in a spherical shape are manufactured by machining, the wall thickness can be made uniform and thin. Thermal stress can be relaxed. Thereby, the reliability of the steam valve can be improved. Further, even under high-temperature and high-pressure steam conditions, the thermal stress can be relaxed and the reliability of the steam valve can be maintained.
[0016]
Further, the steam valve of the present invention has a valve main body having a spherical valve chamber having a steam inlet hole,
A reinforcing portion formed around the inflow hole, a steam inflow portion welded to the valve body so as to communicate with the inflow hole, and the valve body Along the central axis of machining when forming the outline of The valve body having a formed steam outlet The inner and outer surfaces, the reinforcing portion and the steam outflow portion are formed by machining and integrally formed. It is characterized by that.
[0017]
According to this steam valve, the shape of the valve body can be simplified, the overall length of the valve body itself can be shortened, the weight can be reduced, and the production cost can be reduced.
[0018]
Further, since the steam outlet pipe is manufactured integrally with the valve body by machining, there is no structural welded portion of the steam outlet pipe where thermal stress tends to concentrate in the valve body. Thereby, since concentration of thermal stress in the valve body can be avoided, the quality as a steam valve can be remarkably improved.
[0019]
The method for producing the steam valve of the present invention comprises: A steam valve manufacturing process comprising: a valve body manufacturing process for forming a valve body of the steam valve; and a steam inflow / outlet manufacturing process for forming a steam inflow portion and a steam outflow portion in the valve body formed in the valve body manufacturing process. A method of manufacturing the valve body comprising: Using the first axis as the central axis for machining, It is a rotating body shape with the first axis as a rotation axis by machining. The outer shape is formed by cutting the outer shape into a shape in which two spheres are connected and the outer shape forming step. By machining A through hole is formed in the cut material with the first axis as the central axis. By machining A through-hole forming step to be formed, and a second axis that is orthogonal to the first axis and passes through the center of one of the two spheres formed in the outer shape forming step. The first recess in the sphere By machining The inside of the one sphere having the recess formed by the first recess forming step to be cut and the first recess forming step is centered on the second axis. By machining Cutting, forming a substantially spherical space, and forming a reinforcing portion around the opening of the first recess, and forming the outer shape perpendicular to the first axis. A second axis is formed on the other sphere with the third axis passing through the center of the other sphere as the central axis. By machining The inside of the other sphere having the recess formed by the second recess forming step to be cut and the second recess forming step is centered on the third axis. By machining A second space forming step of cutting and forming a substantially spherical space and forming a reinforcing portion around the opening of the second recess; The steam inflow / outlet manufacturing process comprises A steam inflow portion welding step in which a steam inflow portion is welded to the one sphere so as to communicate with the opening formed in the first recess formation step; and an opening formed in the second recess formation step. A steam outlet portion welding step for welding the steam outlet portion to the other sphere so as to communicate with each other; With It is characterized by that.
[0020]
According to this steam valve manufacturing method, the center axis of machining of the outer peripheral surface of the steam valve and the center axis of machining of the inner peripheral surface are set separately, and the outer peripheral surface and inner peripheral surface of the steam valve are separately set. By cutting, a reinforcement part can be formed around the opening part of the 1st and 2nd recessed part.
[0021]
Further, by making the shape of the valve chamber forming the steam valve spherical and providing the reinforcing portion, the thickness of the entire valve main body can be reduced, and the weight can be reduced and the manufacturing cost can be reduced.
[0022]
Moreover, the absolute value of the generated thermal stress itself can be kept low by making the valve chamber forming the steam valve spherical. Furthermore, since the valve body is manufactured by machining, the wall thickness can be made uniform and thin, so that the thermal stress at the time of starting the steam turbine can be reduced. Thereby, the reliability of the steam valve can be improved. Further, even under high-temperature and high-pressure steam conditions, the thermal stress can be relaxed and the reliability of the steam valve can be maintained.
[0023]
In addition, the method for manufacturing the steam valve of the present invention includes: A steam valve manufacturing method comprising: a valve body manufacturing process for forming a valve body of a steam valve; and a steam inflow part manufacturing process for forming a steam inflow part in the valve body formed in the valve body manufacturing process, The valve body forming process Using the first axis as the central axis for machining, It is a rotating body shape with the first axis as a rotation axis by machining. The outer shape is formed by the outer shape forming step of cutting into a spherical shape and the outer shape forming step. By machining A through hole is formed in the cut material with the first axis as the central axis. By machining A through-hole forming step to be formed, and a concave portion in the sphere with a second axis passing through the center of the sphere formed in the outer shape forming step as a central axis perpendicular to the first axis. By machining A recess forming step for cutting, and the inside of the sphere having the recess formed by the recess forming step, with the second axis as a central axis. By machining A space forming step of cutting to form a substantially spherical space and forming a reinforcing portion around the opening of the concave portion; The steam inflow part manufacturing process comprises A steam inflow portion welding step of welding the steam inflow portion to the sphere so as to communicate with the opening formed by the recess forming step; Prepare It is characterized by that.
[0024]
According to this steam valve manufacturing method, the shape of the valve body of the steam valve can be simplified, the overall length of the valve body itself can be shortened, and the weight can be reduced and the manufacturing cost can be reduced.
[0025]
Further, since the steam outlet pipe is manufactured integrally with the valve body by machining, there is no structural welded portion of the steam outlet pipe where thermal stress tends to be concentrated in the valve body. Thereby, since concentration of thermal stress in the valve body can be avoided, the quality as a steam valve can be remarkably improved.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0027]
(First embodiment)
An outline of the steam valve 1 according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a cross-sectional view of a steam valve 1 according to a first embodiment. FIG. 2 shows a cross-sectional view of the valve body 2 of the steam valve 1.
[0028]
The steam valve 1 according to the first embodiment mainly includes a valve main body 2, an upper lid 3, a main valve 4, a valve rod 5, a guide piece 6, a valve seat 7, a strainer 8, and a bracket 9.
[0029]
The valve body 2 includes a steam inflow side valve body 2a and a steam outflow side valve body 2b. An upper lid 3 is fixed with bolts 10 in the upper opening of the steam inflow side valve body 2a. In addition, a valve seat 7 is fixed to a communication portion between the steam inflow side valve body 2a and the steam outflow side valve body 2b, and a strainer 8 that captures foreign matter in the steam is provided between the valve seat 7 and the upper lid 3. is set up.
[0030]
A valve stem 5 attached to the main valve 4 is slidably supported by the guide piece 6 and is vertically moved by an actuator (not shown) fixed to the steam outlet side valve body 2b by a bolt 10 via a bracket 9. Operated on.
[0031]
The steam flows in from the steam inflow hole 11 opened in the steam inflow side valve body 2a, passes through a flow path formed between the main valve 4 and the valve seat 7, and is opened in the steam outflow side valve body 2b. It flows out from the steam outlet hole 12. A steam inlet pipe 13 is connected to the steam inlet hole 11, and a steam outlet pipe 14 is connected to the steam outlet hole 12.
[0032]
Furthermore, a reinforcement surplus portion 15 is provided around the steam inlet hole 11 on the inner wall of the steam inlet side valve body 2a for reinforcement. Further, similarly to the inner wall of the steam inflow side valve body 2a, a reinforcing surplus portion 15 is provided around the steam outflow hole 12 on the inner wall of the steam outflow side valve body 2b for reinforcement. Here, the reinforcing surplus portion 15 is, for example, the volume removed from the steam inflow side valve body 2a in order to provide the steam inflow hole 11 in the steam inflow side valve body 2a, as shown on the steam inflow side valve body 2a side. The part which supplemented the structural member of the steam inflow side valve main body 2a corresponding to to a predetermined range. A method for calculating the reinforcement surplus portion 15 will be described later.
[0033]
The reinforcement surplus portion 15 is not limited to being formed on the inner walls of the steam inflow side valve body 2a and the steam outflow side valve body 2b, but is formed on the outer walls of the steam inflow side valve body 2a and the steam outflow side valve body 2b. May be.
[0034]
Since the present invention is mainly characterized by the configuration and manufacturing method of the valve body 2 of the steam valve 1, the valve body 2 will be mainly described below with reference to FIG.
[0035]
The material of the valve body 2 is made of, for example, cobalt-base alloy steel that is excellent in manufacturability of large steel ingots and excellent in high-temperature strength, and is formed by forging. The cobalt-base alloy steel used here is, for example, one containing cobalt by 50% or more by weight.
[0036]
The forged member has no inherent defect, and it is not necessary to take a margin on the allowable stress to be considered at the time of designing, such as a casting coefficient, as compared with the cast member. Therefore, the thin valve body 2 can be formed. Generation | occurrence | production of a thermal stress can be relieve | moderated by forming the valve main body 2 with thin wall. However, even if it is manufactured by forging, it may be difficult to obtain the effect sufficiently depending on the modeling dimensions. Therefore, the valve body 2 of the present invention is a valve for accurately finishing the thickness of each part. Both the inner and outer surfaces of the main body 2 were manufactured by machining.
[0037]
As described above, the valve body 2 shown in FIG. 2 includes the steam inflow side valve body 2a and the steam outflow side valve body 2b, and the valve body 2 is formed from one material by machining. The valve body 2 is simplified in shape so that the entire inner and outer surfaces can be machined. Furthermore, in order to relieve the thermal stress at the time of starting the steam turbine, the spherical body shape is adopted in the portion where the maximum thermal stress of the valve body 2 is generated as a means for making the wall as thin as possible, and the generated thermal stress itself. The absolute value of is kept low.
[0038]
In addition, a steam inlet hole 11 is opened in the steam inlet side valve body 2a, and a steam outlet hole 12 is opened in the steam outlet side valve body 2b. The valve body 2 is also a pressure vessel. When the pressure vessel is used, since the through holes of the steam inflow hole 11 and the steam outflow hole 12 are opened in the body portion of the valve body 2, the strength is insufficient. In view of this, the valve body 2 is provided with a reinforcing surplus portion 15 based on the first type pressure vessel structure standard.
[0039]
Here, the reinforcing surplus portion 15 is a reinforcing portion for avoiding the structural strength in the vicinity thereof from being reduced by the steam inlet hole 11 and the steam outlet hole 12 opened in the body portion of the valve body 2. , Formed near the openings of the steam inlet hole 11 and the steam outlet hole 12. The minimum cross-sectional area (A) of the reinforcing surplus portion 15 can be obtained by the following equation.
[0040]
A = F × t _r Xd ... Formula (1)
Where d is the maximum hole diameter excluding corrosion allowance, t _r Is the thickness required for calculation of the body of the valve body 2 without a hole, and F is a coefficient.
[0041]
FIG. 3 shows an example of a cross-sectional view of the reinforced valve body 20 and the pipe 21 connected to the opening 22 of the valve body 20 with the minimum cross-sectional area calculated based on the formula (1). The total area of the shaded portion B, which is a reinforcement surplus portion, is equal to the area of the shaded portion A calculated by Equation (1).
[0042]
In this way, by reinforcing the vicinity of the openings of the steam inlet hole 11 and the steam outlet hole 12 with a minimum cross-sectional area, the overall thickness of the valve body 2 can be reduced, resulting in a balanced shape as a product. Both the total weight and the manufacturing cost of the steam valve 1 can be minimized.
[0043]
(Manufacturing method of valve body 2)
Next, an example of a method for manufacturing the valve body 2 will be described with reference to FIGS. 4 to 11 show cross-sectional views in each manufacturing process of the valve body 2. Here, the valve body 2 is manufactured by machining using a machine tool such as an NC combined vertical lathe, for example.
[0044]
As shown in FIG. 4, for example, the material 30 is cut by using the Y-Y axis of the material 30 in the shape of a cylinder or the like as the central axis for machining, and the two spheres are connected to each other. The outer shape of the valve body 2 having cylindrical portions at both ends in the Y-Y axis direction is formed (FIG. 5).
[0045]
A through hole 31 is formed along the Y-Y axis in the center of the material 30 on which the outer shape of the valve body 2 is formed (FIG. 6). The diameter of the through hole 31 is preferably substantially equal to the diameter of the opening formed in the lower part of the steam outlet side valve body 2b closed by the bracket 9.
[0046]
Furthermore, the fixed part of the guide piece 6 installed in the steam outflow side valve body 2b, the fixed part of the valve seat 7 installed in the communication part between the steam inflow side valve body 2a and the steam outflow side valve body 2b, and the steam outflow side The through hole 31 is further cut with a diameter corresponding to the diameter of the fixed portion of the upper lid 3 installed in the valve body 2b (FIG. 7).
[0047]
Subsequently, in order to form the steam inflow hole 11 of the steam inflow side valve main body 2a, the material 30 is machined on the XA-XA axis orthogonal to the Y-Y axis and passing through the center of the steam inflow side valve main body 2a. Cutting is performed along the XA-XA axis as the central axis. And the cutting is stopped leaving the thickness of the wall part of the steam inflow side valve body 2a on the opposite side, and a recess is formed by the cutting (FIG. 8).
[0048]
Further, the material 30 has a machining center on the XB-XB axis that is orthogonal to the Y-Y axis and passes through the center of the steam outlet side valve body 2b in order to form the steam outlet hole 12 of the steam outlet side valve body 2b. Cutting is performed along the XB-XB axis as the axis. And the cutting is stopped leaving the thickness of the wall part of the steam outflow side valve body 2b on the opposite side, and a recess is formed by the cutting (FIG. 8).
[0049]
Next, the inside of the raw material 30 is cut using the XA-XA axis as the central axis of machining, and a substantially spherical inner wall is formed (FIG. 9). In addition, as shown in FIG. 9, in the inner wall part by the side of the steam inflow hole 11, cutting is performed leaving the reinforcement surplus part 15. As shown in FIG.
[0050]
Subsequently, with the XB-XB axis as the central axis of machining, the inside of the material 30 is cut to form a substantially spherical inner wall (FIG. 10). In addition, as shown in FIG. 10, in the inner wall part by the side of the steam outflow hole 12, cutting is performed leaving the reinforcement surplus part 15. In the process shown in FIG. 10, the valve body 2 composed of the steam inflow side valve body 2a and the steam outflow side valve body 2b is completed.
[0051]
Next, the steam inlet pipe 13 is welded so as to communicate with the steam inlet hole 11 of the steam inlet side valve body 2a. Further, the steam outlet pipe 14 is welded so as to communicate with the steam outlet hole 12 of the steam outlet side valve body 2b (FIG. 11).
[0052]
According to the steam valve 1 of the first embodiment, the central axis of machining of the outer peripheral surface of the steam valve 1 and the central axis of machining of the inner peripheral surface are set separately, and the outer peripheral surface of the steam valve 1 and By cutting the inner peripheral surface separately, it is possible to form a reinforcing extra portion 15 necessary for calculation in the vicinity of the steam inlet hole 11 and the steam outlet hole 12 on the inner peripheral surface.
[0053]
Moreover, the shape of the steam inflow side valve body 2a and the steam outflow side valve body 2b is a sphere, and by providing the reinforcement surplus portion 15, the thickness of the entire valve body 2 can be reduced, and the weight is reduced. The production cost can be reduced.
[0054]
Further, by making the shapes of the steam inflow side valve body 2a and the steam outflow side valve body 2b spherical, the absolute value of the generated stress itself can be kept low.
[0055]
Furthermore, since the steam inflow side valve body 2a and the steam outflow side valve body 2b, which are formed in a spherical shape, are manufactured by machining, the thickness of the wall portion can be made uniform and thin. The thermal stress such as can be relaxed. As a result, the reliability of the steam valve can be improved, and maintenance over time can be easily performed. Further, even under high-temperature and high-pressure steam conditions, the thermal stress can be relaxed and the reliability of the steam valve can be maintained.
[0056]
As shown in FIG. 12, the steam inlet hole 11 in the valve body 2 of the steam valve 1 of the first embodiment is formed by a short pipe portion 42 having a groove portion 41 integrated with the steam inlet side valve body 40a. It may be configured. Further, the reinforcing surplus portion 15 and the groove portion 41 of the short tube portion 42 are formed with the XA-XA axis as the central axis of machining. Then, the steam inlet pipe 13 is welded to the groove portion 41 of the short pipe portion 42.
[0057]
Although not shown in FIG. 12 for the steam outlet side valve body side, the steam outlet hole 12 is formed in the same manner as the steam inlet side valve body 2a.
Thus, by forming the steam inflow hole 11 by the short pipe part 42 having the groove part 41 integrated with the steam inflow side valve body 2a, the groove part 41 of the short pipe part 42, the steam inflow pipe 13 and The thickness of the welded portion becomes flat, and nondestructive inspection can be easily performed.
[0058]
Further, as shown in FIG. 13, the steam inlet pipe 13 and the steam outlet pipe 14 may be constituted by different diameter pipes, and the larger diameter side of the different diameter pipes may be welded to the valve body 2. In this case, since the hole diameters of the steam inlet hole 11 and the steam outlet hole 12 can be made larger than the hole diameters of the steam inlet hole 11 and the steam outlet hole 12 of the valve body 2 shown in FIG. 2, the XA-XA axis Further, machining performed with the XB-XB axis as the central axis is facilitated, and productivity can be improved.
[0059]
Further, in the valve body 2 shown in FIG. 2, the spherical inner wall surface and outer wall surface of the steam inflow side valve body 2a are configured based on the same center point, but as shown in FIG. The center point may be different.
[0060]
In the steam inflow side valve body 2a shown in FIG. 14, the center point of the inner wall surface is located on the steam inflow hole 11 side with respect to the center point of the outer wall surface on the XA-XA axis. In this way, by shifting the center of the inner wall surface by a predetermined distance toward the steam inflow hole 11 side, the steam flow path between the outer periphery of the strainer (not shown) and the inner wall surface of the steam inflow side valve body 2a is evenly distributed. Can be configured. Note that the steam outlet side valve body 2b can also be configured with the spherical inner wall surface and the outer wall surface having different center points, similarly to the steam inlet side valve body 2a.
[0061]
In the valve body of the embodiment shown so far, for example, as shown in FIG. 2, the reinforcing surplus portion 15 has a planar inner peripheral surface in a direction perpendicular to the XA-XA axis or the XB-XB axis. However, the present invention is not limited to this shape. For example, as shown in FIG. 15, the radius of the spherical inner wall of the steam inflow side valve body 2a is gradually decreased toward the steam inflow hole 11 side, and the reinforcement surplus part 15 is provided on the steam inflow hole 11 side of the inner wall. It can also be formed. Similarly, the radius of the spherical inner wall of the steam outflow side valve body 2b may be gradually decreased toward the steam outflow hole 12 to form the reinforcing extra wall 15 on the steam outflow hole 12 side of the inner wall. it can.
[0062]
The material of the valve body 2 used here is a forged member having no inherent defects. However, as the precision casting technology and new material development progress in the future, a cast member having the same quality as the forged member described above can be obtained. If it becomes, not only a forging member but a casting member can also be used as a raw material which forms the valve main body 2. FIG. Also in this case, the same effect as the case where the valve main body 2 is manufactured using the forged member described above can be obtained.
[0063]
Moreover, although an example of the manufacturing method of the valve main body 2 was demonstrated to FIG. 4 thru | or 11, the manufacturing method of the valve main body 2 is not restricted to this, If the shape of the valve main body 2 is manufactured by machining. Good.
[0064]
(Second Embodiment)
An outline of the valve body 50 of the steam valve according to the second embodiment of the present invention will be described with reference to FIGS. FIG. 16 shows a cross-sectional view of the valve body 50 of the second embodiment. FIG. 17 shows a perspective view of the steam inlet pipe 51.
[0065]
The valve body 50 shown in FIG. 16 includes a steam inflow side valve body 50a and a steam outflow side valve body 50b, and the valve body 50 is formed from one material by machining. The valve body 50 is simplified in shape so that the entire inner and outer surfaces can be machined. Furthermore, in order to relieve the thermal stress at the time of starting the steam turbine, as a means for making the wall as thin as possible, a spherical body shape is adopted in the portion where the maximum thermal stress of the valve body 50 is generated, and the generated thermal stress itself. The absolute value of is kept low.
[0066]
Further, the steam inflow side valve body 50a has an opening having a groove 52 for welding the steam inflow pipe 51 to the XA-XA axis from the center point Oa of the spherical inner wall of the steam inflow side valve body 50a. It is symmetrically formed corresponding to the angle α. The angle α is set to the smaller one of γ × 2 and δ × 2 as the maximum angle, and the angle α is configured with an angle equal to or less than the maximum angle. Here, the angle γ is centered at a point P where the outer wall 55 of the cylindrical portion of the steam inflow side valve body 50a perpendicular to the surface 54 to which the upper lid 3 is fixed intersects the spherical outer wall of the steam inflow side valve body 50a. This is an angle formed by the straight line connecting the points Oa and the XA-XA axis. Further, the angle δ is an angle formed by a straight line connecting the point Q where the outer walls of the steam inflow side valve main body 50a and the steam outflow side valve main body 50b intersect with the center point Oa, and the XA-XA axis.
[0067]
Similarly to the steam inflow side valve body 50a, the steam outflow side valve body 50b has an opening having a groove 52 for welding the steam outflow pipe 53, and a spherical inner wall of the steam outflow side valve body 50b. Are formed symmetrically with respect to the XB-XB axis from the center point Ob and corresponding to the angle β. For the angle β, the smaller one of θ × 2 and φ × 2 is the maximum angle, and the angle β is configured with an angle equal to or less than the maximum angle. Here, the angle θ is centered at the point R where the outer wall 57 of the cylindrical portion of the steam outlet side valve body 50b perpendicular to the surface 56 to which the bracket 9 is fixed and the spherical outer wall of the steam outlet side valve body 50b intersect. This is an angle formed by a straight line connecting the point Ob and the XB-XB axis. Further, the angle φ is an angle formed by a straight line connecting the point S where the outer walls of the steam inflow side valve body 50a and the steam outflow side valve body 50b intersect with the center point Ob, and the XB-XB axis.
[0068]
The diameters of the openings of the steam inflow side valve body 50a and the steam outflow side valve body 50b of the valve body 50 of the second embodiment are the same as those of the steam inflow side valve body 2a of the valve body 2 of the first embodiment. Since it can be formed sufficiently larger than the diameter of the steam outflow hole 12 of the inflow hole 11 and the steam outflow side valve body 2b, the working efficiency can be improved. Further, in the steam inflow side valve body 50a and the steam outflow side valve body 50b, since the diameter of the opening is sufficiently large, it becomes easy to form the reinforcing surplus portion 58 in an arbitrary part of the valve body 50, which is optimal. Thus, the valve body 50 can be reinforced.
[0069]
The steam inflow pipe 51 is formed by machining from one material, and the shape is simplified so that the entire inner and outer surfaces can be machined. Further, the steam inflow pipe 51 is formed to have a part of a spherical wall portion of the steam inflow side valve body 50a.
[0070]
The tapered portion 51a of the steam inflow pipe 51 facing the surface of the groove 52 of the opening of the steam inflow side valve body 50a has an angle α of about the XA-XA axis as a central axis. Moreover, the taper part 51a has a groove part so that it may be optimally welded with the opening part of the steam inflow side valve main body 50a. Further, as shown in FIG. 16, the steam inflow pipe 51 is formed by machining with the reinforcement surplus portion 58 integrated. And the steam inflow pipe 51 is welded to the opening part of the steam inflow side valve main body 50a.
[0071]
Similarly to the steam inflow pipe 51, the steam outflow pipe 53 is formed by machining from one material, and the shape is simplified so that the entire inner and outer surfaces can be machined. The steam outflow pipe 53 is formed to have a part of the spherical wall portion of the steam outflow side valve body 50b.
[0072]
As shown in FIG. 16, the tapered portion 53a of the steam outlet pipe 53 facing the surface of the groove portion 52 of the opening of the steam outlet side valve body 50b has an angle β of about the XB-XB axis as a central axis. Have. Further, the tapered portion 53a has a groove portion so as to be optimally welded to the opening portion of the steam outflow side valve main body 50b. Furthermore, the steam outflow pipe 53 is formed by machining with the reinforcement surplus portion 58 integrated. The steam outlet pipe 53 is welded to the opening of the steam outlet side valve body 50b.
[0073]
Since the valve main body 50, the steam inflow pipe 51 and the steam outflow pipe 53 are separately manufactured by machining, for example, the valve main body 50 is made of cobalt which is excellent in manufacturability of large steel ingots and excellent in high temperature strength in a weight ratio. The cobalt base alloy steel containing 50% or more can be manufactured, and the steam inflow pipe 51 and the steam outflow pipe 53 can be made of nickel base alloy steel containing 35% or more by weight of nickel excellent in high temperature strength. Further, for example, the valve body 50 can be made of a cast member, and the steam inlet pipe 51 and the steam outlet pipe 53 can be made of a forged member.
[0074]
The valve body 50 is basically manufactured in the same process as the manufacturing process of the valve body 2 described in the first embodiment.
[0075]
As described above, an optimal steam valve can be manufactured by selecting a material or a material manufacturing method and using the material according to the generated stress (required strength) of the component.
[0076]
According to the steam valve of the second embodiment, the steam inflow pipe 51 and the steam outflow pipe 53 are welded by opening the spherical wall portion of the valve main body 50, so that the opening diameter of the wall portion is increased. Thus, machining inside the valve body 50 is facilitated, and productivity can be improved.
[0077]
Further, since the steam inflow pipe 51 and the steam outflow pipe 53 are formed integrally with the reinforcement surplus portion 58 by machining, separately from the valve body 50, the formation of the reinforcement surplus portion 58 is easy, and production It is possible to improve the performance. Furthermore, since the shape of the reinforcement surplus part 58 can be arbitrarily formed according to a use, a more exact reinforcement part can be formed. Moreover, the shape of the steam inflow side valve body 50a and the steam outflow side valve body 50b is a sphere, and the reinforcement surplus portion 58 is provided, so that the thickness of the entire valve body 50 can be reduced, and the weight is reduced. The production cost can be reduced.
[0078]
Further, a groove is accurately formed by machining in the opening of the steam inflow side valve body 50a, the opening of the steam outflow side valve body 50b, the tapered part 51a of the steam inflow pipe 51 and the tapered part 53a of the steam outflow pipe 53. Therefore, the optimum welding can be performed and the quality of the welded portion can be improved.
[0079]
In addition, since the steam inlet pipe 51 and the steam outlet pipe 53 are structurally welded at the spherical portion, the stress is directly generated due to the openings in the wall portions of the spherical steam inlet side valve body 50a and the steam outlet side valve body 50b. The part to do can be avoided. Thereby, the quality of the welding part of the steam inflow pipe 51 and the steam outflow pipe 53 can be remarkably improved.
[0080]
(Third embodiment)
An outline of the steam valve 60 according to the third embodiment of the present invention will be described with reference to FIG. FIG. 18 shows a cross-sectional view of the steam valve 60 of the third embodiment.
[0081]
The valve body 61 of the steam valve 60 of the third embodiment is configured using only the steam inflow side valve body 2a side of the steam valve 1 of the first embodiment shown in FIG.
[0082]
The steam valve 60 of the third embodiment is mainly composed of a valve body 61, an upper lid 62, a main valve 63, a valve rod 64, a valve seat 65, and a strainer 66.
[0083]
The valve main body 61 manufactured by machining has a steam inlet hole 68, an upper opening 69 and a steam outlet hole 70, and a steam inlet pipe 71 is welded to the steam inlet hole 68. In addition, a reinforcing surplus portion 72 is provided on the side of the steam inflow hole 68 on the spherical inner wall of the valve body 61.
[0084]
An upper lid 62 is fixed to the upper opening 69 of the valve body 61 with bolts 67. A guide hole for the valve rod 64 is opened in the upper lid 62 along the Y-Y axis that is the central axis of the steam valve 60. A main valve 63 is connected to one end of the valve stem 64, and the steam flow path formed between the main valve 63 and the valve seat 65 is opened and closed by the movement of the valve stem 64 in the Y-Y axis direction. The movement of the valve stem 64 in the Y-Y axis direction is performed by an actuator or the like (not shown). In addition, a strainer 66 is installed between the valve seat 65 and the upper lid 62 to capture foreign substances in the steam.
[0085]
The steam flows in from a steam inflow hole 68 opened in the valve body 61, passes through a steam flow path formed between the main valve 63 and the valve seat 65, and flows out from the steam outflow hole 70.
[0086]
The valve main body 61 and the steam inflow pipe 71 are formed of, for example, nickel-base alloy steel containing 35% or more by weight of nickel, which has high strength in a high temperature range and is easy to manufacture a small steel ingot. It is not something that can be done.
[0087]
(Manufacturing method of valve body 61)
Next, an example of a method for manufacturing the valve body 61 will be described with reference to FIGS. 19 to 25 show cross-sectional views in each manufacturing process of the valve main body 61. Here, the valve body 61 is manufactured by machining using a machine tool such as an NC combined vertical lathe, for example.
[0088]
As shown in FIG. 19, for example, the material 80 is cut using the Y-Y axis of the material 80 in the shape of a cylinder or the like as the center axis of machining, and the sphere part and both ends of the sphere part in the Y-Y axis direction The outer shape of the valve body 61 having a cylindrical portion is formed (FIG. 20).
[0089]
A through hole 81 is formed along the Y-Y axis at the center of the material 80 on which the outer shape of the valve body 61 is formed (FIG. 21).
[0090]
Further, the through hole 81 is further cut with a diameter corresponding to the diameter of the fixed portion of the valve seat 65 (FIG. 22).
[0091]
Subsequently, in order to form the steam inflow hole 68 of the valve body 61, the material 80 is orthogonal to the Y-Y axis and passes through the center of the valve body 61 with the XA-XA axis as the center axis of machining. Cutting along the XA axis. And the cutting is stopped leaving the thickness of the wall part of the valve main body 61 on the opposite side, and a recessed part is formed by the cutting (FIG. 23).
[0092]
Next, in the valve main body 61, the inside of the valve main body 61 is cut using the XA-XA axis as a central axis for machining, thereby forming a substantially spherical inner wall (FIG. 24). In addition, as shown in FIG. 24, the steam inflow hole 68 side of an inner wall is cut, leaving the reinforcement surplus part 82. FIG. The valve body 61 is completed by the process shown in FIG.
[0093]
Subsequently, the steam inlet pipe 71 is welded so as to communicate with the steam inlet hole 68 of the valve body 61 (FIG. 25).
[0094]
According to the steam valve 60 of the third embodiment, the shape of the valve body 61 can be simplified, the entire length of the valve body 61 itself can be shortened, and the weight can be reduced and the manufacturing cost can be reduced.
[0095]
Further, since the steam outlet pipe is manufactured integrally with the valve main body 61 by machining, the valve main body 61 does not have a structural weld portion of the steam outlet pipe where thermal stress tends to concentrate. Thereby, since concentration of thermal stress in the valve body 61 can be avoided, the quality of the steam valve 60 can be significantly improved.
[0096]
Furthermore, the valve body 61 is formed in a spherical shape and the reinforcement surplus portion 82 is provided, whereby the thickness of the entire valve body 61 can be reduced, and the weight can be reduced and the manufacturing cost can be reduced.
[0097]
In addition, the valve body 50 of the steam valve according to the second embodiment can employ a configuration in which the overall length is shortened as in the valve body 61 of the steam valve according to the third embodiment.
[0098]
【The invention's effect】
According to the steam valve and the steam valve manufacturing method of the present invention, thermal stress can be alleviated even under high-temperature and high-pressure steam conditions, and the reliability of the steam valve can be maintained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a steam valve according to a first embodiment.
FIG. 2 is a cross-sectional view of the valve body of the steam valve according to the first embodiment.
FIG. 3 is a cross-sectional view showing an example of a reinforced valve body and piping connected to an opening of the valve body.
FIG. 4 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 5 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 6 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 7 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 8 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 9 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 10 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 11 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 12 is a cross-sectional view showing an example of the configuration of a steam inflow side valve body.
FIG. 13 is a cross-sectional view showing an example of the configuration of the valve body.
FIG. 14 is a sectional view showing an example of the configuration of the valve body.
FIG. 15 is a cross-sectional view showing an example of the configuration of the valve body.
FIG. 16 is a cross-sectional view of a valve body according to a second embodiment.
FIG. 17 is a perspective view of a steam inflow pipe.
FIG. 18 is a cross-sectional view of a steam valve according to a third embodiment.
FIG. 19 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 20 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 21 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 22 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 23 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 24 is a cross-sectional view showing a manufacturing process of the valve body.
FIG. 25 is a cross-sectional view showing the manufacturing process of the valve body.
FIG. 26 is a cross-sectional view of a conventional steam valve.
[Explanation of symbols]
1 ... Steam valve
2. Valve body
2a ... Steam inlet valve body
2b ... Steam outlet valve body
3. Top cover
4 ... Main valve
5 ... Valve stem
6 ... Guide piece
7 ... Valve seat
8 ... Strainer
9 ... Bracket
10 ... Bolt
11 ... Steam inlet
12 ... Steam outflow hole
13. Steam inlet pipe
14 ... Steam outflow pipe
15 ... Reinforcement surplus part

Claims

A first valve body having a spherical valve chamber having a steam inlet hole;
A first reinforcing portion formed around the inflow hole;
A steam inflow portion welded to the first valve body so as to communicate with the inflow hole;
A second valve body that communicates with the first valve body, has a steam outlet hole, and has a spherical valve chamber;
A second reinforcing portion formed around the outflow hole;
A steam outflow portion welded to the second valve body so as to communicate with the outflow hole,
Inner and outer surfaces of the first valve body and the second valve body, and the first reinforcing portion and the second reinforcing portion are formed by machining, and the first valve body and the second valve body are formed by machining. A steam valve , wherein a valve body, the first reinforcing portion, and the second reinforcing portion are integrally formed .

The steam valve according to claim 1, wherein the first valve body and the second valve body are integrally formed from the same material.

The steam inflow part has a part of a wall part constituting the spherical valve chamber of the first valve body, and is configured integrally with a part of the wall part,
The steam outflow part has a part of a wall part constituting a spherical valve chamber of the second valve body, and is configured to be integrated with a part of the wall part. The steam valve according to 1 or 2.

The first valve body, the first reinforcing portion, the steam inflow portion, the second valve body, the second reinforcing portion, and the steam outflow portion are formed of a forged steel member. The steam valve according to any one of claims 1 to 3.

The first valve main body, the first reinforcing portion, the steam inflow portion, the second valve main body, the second reinforcing portion, and the steam outflow portion are formed of a cast steel member. The steam valve according to any one of claims 1 to 3.

At least one of the first valve body, the first reinforcing portion, the steam inflow portion, the second valve body, the second reinforcing portion, and the steam outflow portion is formed of a forged steel member, The steam valve according to any one of claims 1 to 3, wherein the remainder is formed of a cast steel member.

The first valve main body, the first reinforcing portion, the steam inflow portion, the second valve main body, the second reinforcing portion, and the steam outflow portion are nickel bases containing 35% or more of nickel by weight. The steam valve according to any one of claims 1 to 3, wherein the steam valve is formed of any one of alloy steel and cobalt-based alloy steel containing 50% or more by weight of cobalt.

A valve body having a spherical valve chamber with a steam inlet hole;
A reinforcing portion formed around the inflow hole;
A steam inflow portion welded to the valve body so as to communicate with the inflow hole;
A steam outlet formed along a central axis of machining when forming the outer shape of the valve body,
The steam valve characterized in that the inner and outer surfaces of the valve main body, the reinforcing portion and the steam outflow portion are formed by machining and are integrally formed .

A steam valve manufacturing process comprising: a valve body manufacturing process for forming a valve body of the steam valve; and a steam inflow / outlet manufacturing process for forming a steam inflow portion and a steam outflow portion in the valve body formed in the valve body manufacturing process. A method,
The valve body manufacturing process includes:
An outer shape forming step in which a first axis is a center axis of machining, and a material is machined to form a rotating body having the first axis as a rotation axis ;
A through hole forming step of forming a through hole by machining with the first axis as a central axis in the material whose outer periphery is cut by machining in the outer shape forming step;
A first recess is machined in one sphere with a second axis that is orthogonal to the first axis and passing through the center of one of the two spheres formed in the outer shape forming step as a central axis. A first recess forming step for cutting by processing ;
The inside of the one sphere having the recess formed by the first recess forming step is cut by machining with the second axis as a center axis to form a substantially spherical space, and the first A first space forming step of forming a reinforcing portion around the opening of the concave portion;
A second recess is machined in the other sphere with a third axis that is perpendicular to the first axis and passing through the center of the other sphere of the two spheres formed in the outer shape forming step as a central axis. A second recess forming step for cutting by processing ;
The inside of the other sphere having the recess formed by the second recess forming step is cut by machining with the third axis as a central axis to form a substantially spherical space, and the second A second space forming step of forming a reinforcing portion around the opening of the recess of
With
The steam inflow / outlet manufacturing process comprises:
A steam inflow portion welding step of welding a steam inflow portion to the one sphere so as to communicate with the opening formed by the first recess forming step;
A steam outflow portion welding step of welding a steam outflow portion to the other sphere so as to communicate with the opening formed by the second recess forming step;
A method for manufacturing a steam valve, comprising:

A steam valve manufacturing method comprising: a valve body manufacturing process for forming a valve body of a steam valve; and a steam inflow part manufacturing process for forming a steam inflow part in the valve body formed in the valve body manufacturing process,
The valve body forming process
An outer shape forming step of cutting the material into a spherical shape that is a rotating body shape with the first axis as a rotation axis by machining the first axis as a central axis of machining ;
A through-hole forming step of forming a through-hole by machining with the first axis as a central axis in the material whose outer periphery is cut by machining by the outer shape forming step;
A recessed portion forming step of cutting a recessed portion in the sphere by machining, with a second axis passing through the center of the sphere formed in the outer shape forming step as a central axis perpendicular to the first axis;
The inside of the sphere having the concave portion formed by the concave portion forming step is cut by machining with the second axis as a central axis to form a substantially spherical space, and around the opening of the concave portion. A space forming step for forming the reinforcing portion;
With
The steam inlet production process is
Method for producing a steam valve, characterized in that it comprises a steam inlet welding step of welding the steam inlet to the spherical body so as to communicate with the opening formed by the concave portion forming step.