JP3572183B2

JP3572183B2 - Detector of flow meter and method of manufacturing the same

Info

Publication number: JP3572183B2
Application number: JP31656697A
Authority: JP
Inventors: 勝福田; 譲谷
Original assignee: 株式会社陽和
Priority date: 1997-10-31
Filing date: 1997-10-31
Publication date: 2004-09-29
Anticipated expiration: 2017-10-31
Also published as: JPH11132799A

Description

【０００１】
【発明の属する技術分野】
本発明は流量計の検出子及びその製造方法に関する。
【０００２】
【従来技術】
近年、フッ素樹脂の国内生産量は半導体産業、自動車産業、あるいは各種精密機械産業の発達により急増し、年間１万数千トン／年、年間の増加率は１０％である。これは、フッ素樹脂の化学的、電気的、熱的に優れた特性によるものである。中でもポリテトラフルオロエチレン（以下、ＰＴＦＥという。）は耐薬品性、耐熱性、耐寒性、耐磨耗性、非粘着性、及び低誘電率等の電気的特性などのユニ−クな特性を有し、特性のバランスの良さに関しては他材に類を見ない。
このＰＴＦＥの耐薬品性等の特性を利用して、多くの流量計の検出子が提案されている。例えば、特開昭６２−６３８１９号公報、実開昭６１−８０４２２号公報、実開平５−７７７２７号公報、実開平６−２３１４３号公報、実開平７−１８９７６号公報に開示されている。
以下、従来の流量計の検出子について、図面を用いて説明する。
図６は従来の流量計の検出子の分解図であり、図７は従来の流量計の検出子の透視斜視図であり、図８は従来の流量計の検出子の縦断面図であり、図９は図８のＢ部の拡大図である。
図６において、５１は従来のＰＴＦＥ製の流量計の検出子、５２は下部が円錐状に形成された検出子本体、５３は検出子本体５２の軸部に同軸状に形成されたインサ−ト部材収納部、５４はインサ−ト部材収納部５３の開口部、５５は開口部５４を囲繞する周壁部の蓋部材との当接面、５６は当接面５５の外周囲に形成された開先部、５７は蓋部材、５８は蓋部材５７の当接面、５９は当接面５８の外周囲に開先部５６と対称形状に形成された開先部、６０は蓋部材５７の下面に同軸状に形成された凸部、６１はインサ−ト部材である。
図７乃至図９において、７０は開先部５６と開先部５９の間に充填され溶接されたＰＦＡ等の溶接材、７１は開先部５６、５９と溶接材７０の溶接面、７２は未シ−ル部である。
【０００３】
以上のように構成された従来の流量計の検出子について、以下その製造方法について説明する。
まず、第１工程において、所定量のＰＴＦＥ粉体を加圧成型して、検出子本体５２及び蓋部材５７の加圧成形品を成形する。
次に、第２工程において、第１工程で得られた検出子本体５２及び蓋部材５７の予備成形品を焼成炉に移して焼成し、予備成形品を得る。
次に、第３工程において、第２工程で得られた予備成形品のバリ等の除去、及び所定の寸法に一次加工される。また、検出子本体５２及び蓋部材５７を接合させるために、各々に開先部５６、５９をＶ字状に形成する。
次いで、第４工程において、これらの溶接面を洗浄剤で洗浄し乾燥する等の表面処理を行う。
次に、第５工程において、第４工程で得られた検出子本体５２のインサ−ト部材収納部５３にインサ−ト部材６１が嵌挿される。
次に、第６工程において、インサ−ト部材６１が嵌挿された検出子本体５２と蓋部材５７の溶接面に溶接用の薬品を塗布する。
次いで、第７工程として、検出子本体５２に蓋部材５７の凸部６０を挿入し、当接面５５、５８を接合する。次いで第８工程として開先部５６、５９に溶接材としてフッ素樹脂であるテトラフルオロエチレン−パーフルオロアルキルビニルエーテル重合体（以下、ＰＦＡという。）等の溶接棒をヒ−タ等を用いて、熟練工が一つ一つ加熱しながら開先部５６と５９を溶接する。
次に、第９工程において、第８工程において溶接された流量計の検出子を除冷する。除冷しないとＰＴＦＥとＰＦＡの熱膨張率の相違により溶接部分が剥離するためである。
次いで、第１０工程において、溶接部分の肉盛り等を焼成品は切削加工され、バリ等の除去、及び寸法等が微調整され、流量計の検出子１１が形成される。
【０００４】
その他、ＰＴＦＥ粉体中にインサ−ト部材を埋設して加圧成形し、加圧成形により得られた成形体を焼成して作製される埋設型の流量計の検出子がある。
図１０（ａ）、（ｂ）は従来の埋設型の流量計の検出子の透視斜視図である。８０は従来の埋設型検出子、８１は検出子本体、８２ａ、８２ｂは埋設されたインサ−ト部材である。
インサ−ト部材８２ａ、８２ｂはＰＴＦＥ粉体中に埋設して加圧成形する際に、ＰＴＦＥ粉体の充填斑や、インサ−ト部材を埋設する際に位置ずれを起こし、検出子本体８１の中心軸から左右にズレたり、傾斜して周壁面等に一部が露出していた。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記従来の流量計の検出子は、以下の課題を有していた。
ａ．接合面積が狭いため接合強度が低く、耐久性に欠けるという問題点を有していた。
ｂ．また、開先部の周囲に盛られたＰＦＡを旋盤等による切削の際に剥離し製品収率が低いという問題点を有していた。
ｃ．更に、接合強度が弱いため流量計に使用中に溶接剤のＰＦＡが剥離するという問題点を有していた。
ｄ．接合面積が狭く溶接斑が生じ易いので密封製に欠け、ピンホ−ル等により外部の薬品等が内部に侵入してインサ−ト部材等を腐食させるという問題点を有していた。
ｅ．埋設型の流量計の検出子では、加工の際に、インサ−ト部材の位置が安定せず偏芯し製品収率が低いという問題点を有していた。
ｆ．インサ−ト部材の収納部の側壁厚みが極端に薄くなる場合があり、強度的に不安定になるとともに、ピンホ−ル等により外部の薬品等が内部に侵入してインサ−ト部材等を腐食させる等の問題点を有していた。
ｇ．ＰＴＦＥは溶接処理が困難なため、「検出素子」として加工処理が終了した後、更に他の部品と結合して機能性を向上させるため他の部品と結合しようとしても溶接接合が極めて困難で機能性向上のための二次加工性に欠けるという問題点を有していた。
ｈ．半導体ウェハーの製造時に、ＰＴＦＥ製の流量計検出子は溶剤中にイオンが溶出する場合があり、汎用性に欠けるという問題点を有していた。
【０００６】
本発明は上記従来の課題を解決するもので、接合強度が高く、ピンホ−ル等の発生がなく、インサ−ト部材を所定の位置に固定でき、高精度で流量を測定できる流量計の検出子の提供、及び、接合強度が高く、耐久性に優れ、インサ−ト部材を所定の位置に容易に固定でき、生産作業性や生産性に優れるとともに高品質の流量計の検出子を高い製品収率で生産できる流量計の検出子の製造方法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
上記課題を解決するため、本発明の流量計の検出子及び流量計の検出子の製造方法は以下の手段を有する。
本発明の請求項１に記載の流量計の検出子は、開口部を有する収納部を備えた検出子本体と、前記収納部に嵌挿されるインサ−ト部材と、前記検出子本体の開口部を含む周壁部に覆設して熱融着で前記検出子本体と一体化された蓋部材と、を有し、前記検出子本体及び前記蓋部材の少なくともいずれか１種が改質ＰＴＦＥ又は改質ＰＴＦＥを主成分とする樹脂組成物で形成された構成を有している。
これにより、改質ＰＴＦＥ製の検出子本体と改質ＰＴＦＥ製の蓋部材を直接熱融着するため、開先部を溶接材で接合する場合と異なり、接合面積を広くできることから、接合斑を防止できるとともに接合強度を容易に高くすることができる。また、同一樹脂を直接溶融して接合するため、接合部が一体となり接合斑等の発生を防止し、接合部分のピンホ−ル等の発生を防止することができるという作用を有する。
ここで、改質ＰＴＦＥとしては、懸濁重合時に次の化学式（化１）、（化２）、（化３）で表されるパ−フルオル化エ−テルの１種以上を改質剤として添加して重合されたＰＴＦＥが用いられる。
【化１】

【化２】

【化３】

具体的には、ダイキン工業（株）製の商品名モ−ルディングパウダ−（Ｍ−１１１、Ｍ−１１２、Ｍ−１３７）やヘキスト社製のもの等が用いられる。
組成物として配合される他の合成樹脂としてはＰＦＡ、ＰＴＦＥ等があげられる。
ＰＦＡを加えることにより、熱融着時間の短縮がはかれ、コストを低減化することができる。また、従来のＰＴＦＥを加えることにより熱融着時の保形性を向上できるとともに、希釈剤として優れコストを低減化できる。
ＰＦＡの配合量としては１ｗｔ％〜９５ｗｔ％、好ましくは１ｗｔ％〜８０ｗｔ％が用いられる。１ｗｔ％よりも少なくても添加効果が認められ難く、また８０ｗｔ％よりも多くなるにつれ、熱融着時の保形性が低下し、インサ−ト部材の芯の位置ズレを招きやすいので好ましくない。
従来のＰＴＦＥの配合量としては１ｗｔ％〜９０ｗｔ％、好ましくは１ｗｔ％〜７０ｗｔ％が用いられる。１ｗｔ％よりも少なくても添加効果が認められ難く、また７０ｗｔ％よりも多くなるにつれ、接合強度の低下を招きやすいという傾向が現れだすので好ましくない。
【０００８】
本発明の請求項２に記載の流量計の検出子は、請求項１において、前記検出子本体又は前記蓋部材のいずれか１種が従来のＰＴＦＥ、ＰＦＡのいずれか１種を主成分とする樹脂組成物で形成されている構成を有している。
これにより、従来のＰＴＦＥを主成分とする樹脂組成物を用いた場合、熱融着時の保形性が向上し、インサ−ト部材の位置決めをより正確にすることができるという作用を有する。
またＰＦＡを主成分とする樹脂組成物を用いた場合、熱融着時の処理時間の短縮が可能となり、コストの低減化に効果があるとともに、検出素子を二次加工する場合、他部品との溶接処理の効率が向上するという作用を有する。
【０００９】
本発明の請求項３に記載の流量計の検出子は、請求項１又は２に記載の発明において、前記蓋部材が、底面中央部に前記開口部に嵌合されるリング状又は柱状の凸部と、前記蓋部材が、底面中央部に前記開口部に嵌合されるリング状又は柱状の凸部と、前記収納部の周壁と接合される前記凸部の周壁部と、前記凸部の周囲に前記開口部周壁と接合される蓋部材接合部と、を有し、前記蓋部材が前記凸部の周壁部と前記蓋部材接合部で前記検出子本体の前記収納部の内壁と前記開口部周壁で熱融着され一体化された構成を有している。
これにより、蓋部材が凸部の周壁部を有することで、検出子本体と蓋部材との位置合わせ、仮止め等が容易にできる。また、凸状周壁部が開口部に嵌合されることから接合面積が増加し、外部の薬品等が侵入する侵入経路が長くなるため、ピンホ−ル等による外部の薬品等の侵入を完全に防止することができるとともに、接合強度を著しく高くすることができる。
ここで、凸部の周壁部として、表面が平滑でもよいが、アンカ−効果を付与するとともに接合面積を広め接合強度を高めるために、螺子状に螺子切りし、又は凹凸部を設けてもよい。
【００１０】
本発明の請求項４に記載の流量計の検出子は、請求項１又は２に記載の発明において、前記蓋部材が、接合面側に突出した同軸状の膨出部又は内側に凹んだ凹曲面部からなる蓋部材接合部を有し、前記検出子本体の開口部周壁が前記蓋部材の膨出部又は凹曲面部と当接する傾斜面で形成され、前記蓋部材が前記蓋部材接合部で前記検出子本体の前記開口部周壁で熱融着され一体化された構成を有している。
これにより、接合面を拡大し、より強固な接合強度を得ることができるという作用を有する。
【００１１】
本発明の請求項５に記載の流量計の検出子は、請求項３又は４に記載の発明において、前記開口部周壁と前記蓋部材接合部の対向面が開き角０°〜５°、好ましくは０．１°〜３°、更に好ましくは０．２°〜３°で形成された構成を有している。
これにより、開き角を備えているので、熱溶融時に収納部内の空気を逃散させ接合面に空気孔等の生成を防止できる。
ここで、開き角は、０．２°よりも小さくなるにつれ、収納部内に気体が残留し易いという傾向が現れ易く、また、３°よりも大きくなるにつれ接合強度の低下及び気密性（シ−ル性）の低下が生じ易いという傾向が現れ易いのでいずれも好ましくない。
【００１２】
本発明の請求項６に記載の流量計の検出子の製造方法は、改質ＰＴＦＥ又は改質ＰＴＦＥを主成分とする樹脂組成物の粉体を加圧成形して開口部を有する収納部を備えた検出子本体及び前記開口部に嵌合又は当接される蓋部材接合部を有する蓋部材を成形する加圧成形工程と、前記加圧成形工程で得られた前記検出子本体及び前記蓋部材を焼成する焼成工程と、前記焼成工程で得られた前記検出子本体の前記収納部にインサ−ト部材を挿入する挿入工程と、前記インサ−ト部材が挿入された前記検出子本体の前記開口部及び／又は前記収納部に前記蓋部材を装着する装着工程と、前記装着工程で装着された前記蓋部材に圧力に換算して０＜Ｐ＜２４００〔ｇ／ｃｍ^２〕、好ましくは３０≦Ｐ≦１０００〔ｇ／ｃｍ^２〕の応力を印加しながら加熱して各々を熱融着させる熱融着工程と、を有する構成を有している。
これにより、開口部を有する収納部を備えた検出子本体を形成した後に、インサ−ト部材を挿入することから、検出子本体の所定の位置にインサ−ト部材を確実に挿入できインサ−ト部材の位置ズレを防止できるとともに、インサ−ト部材の位置ずれによる強度の低下、内部クラックの発生、歩留りの低下等を抑えることができる。また、加圧して融着する熱融着工程を有することにより、検出子本体の軸線方向への伸びを抑えるとともに、確実に内側から接合でき、接合強度を高め検出子本体と蓋部との接合強度のバラツキを低減できる。
【００１３】
本発明の請求項７に記載の流量計の検出子の製造方法は請求項６の発明において、前記加圧成形工程において、前記検出子本体又は前記蓋部材のいずれか１種の前記粉体がＰＴＦＥ、ＰＦＡのいずれか１種又はこれらの１種を主成分とする樹脂組成物で形成されている構成を有している。
これにより、ＰＴＦＥを主成分とする樹脂を使用した場合は、熱融着時の保形性が向上し、インサ−ト部材の位置決めがより正確にすることができるという作用を有する。
またＰＦＡを主成分とする樹脂組成物を用いた場合、熱融着時の処理時間の短縮が可能になるという作用を有する。
【００１４】
請求項８に記載の流量計の検出子の製造方法は、請求項６又は７に記載の発明において、前記装着工程において、前記蓋部材を前記検出子本体の収納部に嵌合し装着する際に、前記蓋部材の蓋部材接合部と前記検出子本体の開口部周壁との隙間Ｇを設け、前記隙間Ｇが検出子の全長Ｌに対し、Ｇ／Ｌが０≦Ｇ／Ｌ≦１０％、好ましくは０．１≦Ｇ／Ｌ≦５％の関係を有する構成を有している。
これにより、改質ＰＴＦＥの熱伝導の他、改質ＰＴＦＥ製の蓋部材と改質ＰＴＦＥ製の検出子本体とに隙間に、周囲の気体等からの熱伝導、及び周囲からの熱放射により熱量が与えられ、改質ＰＴＦＥ製の検出子本体及び改質ＰＴＦＥ製の蓋部材の接合部分を容易に加熱することができることから、確実に接合することができる。
また、隙間を所定の長さにすることで、検出子本体と蓋部材の接合個所に肉の盛り上がり現象等を生ずることなく接合個所が目視で識別できないまでに完全に一体化できる。
ここで、比Ｇ／Ｌが０．１％よりも小さくなると、インサ−ト部材と検出子本体との間に隙間が生じ易いという傾向が生じ、また、比Ｇ／Ｌが８％よりも大きくなると、接合強度の低下や接合線が生じ易くなるという傾向が生じるため、いずれも好ましくない。
【００１５】
請求項９に記載の流量計の検出子の製造方法は、請求項６乃至８の内いずれか１項に記載の発明において、前記蓋部材接合部と前記開口部周壁との開き角θが０°＜θ＜５°、好ましくは０．２≦θ≦３°に形成された構成を有している。これにより、改質ＰＴＦＥ製の検出子本体の周壁部と改質ＰＴＦＥ製蓋部材接合面が内側から外側に向かって加熱・加圧により接合され、確実に全面接合されるため高い接合強度が安定かつ確実に得られる。また、この構成により外観テストの際、容易に接合状態を確認できる。また、開き角を有することにより、改質ＰＴＦＥの熱伝導の他に、周囲の気体や、周囲の放射熱により素早く接合部分を加熱することができる。
ここで、開き角θが０．２°よりも小さくなると、重しの圧力にもよるが、接合部の内側に未接合部が発生し易いため接合強度の低下やリ−クの危険性が増すという傾向が生じ、また、開き角θが３°よりも大きくなると、接合部の外側に未接合部が発生し易いため、接合強度の低下やリ−クの危険性が増えるとともに接合個所が現れ易く耐衝撃性に欠けるという傾向が生じるため、いずれも好ましくない。
【００１６】
請求項１０に記載の流量計の検出子の製造方法は、請求項６乃至９の内いずれか１項に記載の発明において、前記熱融着工程において、融着部分の面積をＳ〔ｃｍ^２〕、流量計の全長をＬ〔ｃｍ〕とすると熱融着する際に印加する応力を圧力Ｐ〔ｇ／ｃｍ^２〕に換算した場合に、次式を充たす構成を有している。
Ｐ＝Ａ（Ｔ）×（Ｓ／Ｌ）＋Ｂ（Ｔ）
ここで、Ａ（Ｔ）はＡ（Ｔ）＝−１．１３Ｔ＋α、Ｂ（Ｔ）＝−０．４５４Ｔ＋β、α＝７８０〜８５０、β＝３１０〜３８０、α、βは樹脂の種類や配合量によって決定される定数、Ｔは絶対温度（Ｋ）である。具体的には改質ＰＴＦＥの場合、α＝８１６±１０、β＝３４５±１０が用いられる。
これにより、熱融着処理を施す前の未処理素子に対して、ある程度任意の印加応力の選択が可能となる。これにより多種多様なサイズ・形状の未処理素子に対して、熱融着処理工程に使用する治工具の汎用性が向上し、コストメリットが生じる。また特殊な形状の素子に早急な対応が可能となる。またある程度任意の処理温度の選択が可能となることから熱処理時間の短縮が可能となるという作用を有する。
【００１７】
請求項１１に記載の流量計の検出子の製造方法は、請求項１０に記載の発明において、前記熱融着工程において、印加する応力が圧力Ｐに換算して０＜Ｐ＜２４００〔ｇ／ｃｍ^２〕、好ましくは３０≦Ｐ≦１０００〔ｇ／ｃｍ^２〕であり、かつ、加熱温度Ｔが２５０＜Ｔ＜４５０〔℃〕、好ましくは３２０≦Ｔ≦３９０〔℃〕である構成を有している。
これにより、改質ＰＴＦＥ製の検出子本体と改質ＰＴＦＥ製の蓋部材とを確実に融着することができる。
ここで、圧力Ｐが３０よりも小さくなると、未接合部が発生し易くなるという傾向が生じ、また、圧力Ｐが１０００〔ｇ／ｃｍ^２〕よりも大きくなると、検出子の変形とインサ−ト部材のズレが生じ易いという傾向が生じるため、いずれも好ましくない。
また、温度Ｔが３２０℃よりも低くなると、未接合部が発生し易くなるという傾向が生じ、また、温度Ｔが３９０℃よりも高くなると、合成樹脂が劣化し機械的強度が低下し易いという傾向が生じるため、いずれも好ましくない。
【００１８】
【発明の実施の形態】
図１は本発明の実施の形態における流量計の検出子の分解斜視図であり、図２は本発明の実施の形態における流量計の検出子の透視斜視図であり、図３は本発明の実施の形態における流量計の検出子の要部断面図であり、図４は図３のＡ部の拡大図である。
図１において、１は改質ＰＴＦＥ製の流量計の検出子、２は同軸状に形成された開口部を有する収納部と円錐状に形成された下部とを備えた改質ＰＴＦＥ製の検出子本体、３は改質ＰＴＦＥ製の検出子本体２に同軸状に形成された収納部、４は収納部３の上面に開口した開口部、４ａは開口部４の周壁部、５は開口部４から収納部３に嵌装されるインサ−ト部材、６は改質ＰＴＦＥ製の検出子本体２に接合される改質ＰＴＦＥ製の蓋部材、６ａは蓋部材６の接合面側に同軸状に形成された凸部、６ｂは検出子本体２の開口部４の周壁部４ａに接合される凸部６ａを囲繞する蓋部材接合部、６ｃは開口部４に嵌合される凸部６ａの周壁部である。
図２乃至図４において、７は検出子本体２と蓋部材６の熱融着部、７ａは凸部熱融着部である。
【００１９】
以上のように構成された実施の形態における流量計の検出子について、以下、その製造方法について説明する。
まず、加圧成形工程において、改質ＰＴＦＥ原料粉を改質ＰＴＦＥ製の検出子本体２及び改質ＰＴＦＥ製の蓋部材６の予備成形品を成形するための所定の金型に充填し、油圧式プレス機等を用いて圧力２００〜６００〔ｋｇｆ／ｃｍ^２〕で改質ＰＴＦＥ原料粉を加圧して予備成形品を作製する。この際、ボイドやクラックの原因となる改質ＰＴＦＥ原料粉の間に存在する気体を放出させるため、前記圧力を加圧時間１〜１８０〔ｍｉｎ〕保持する。成形された予備成形品は金型から取り出され、常温で数分〜数日間放置して、内部にトラップされた気体を再度放出させる。
ここで用いられる金型は、炭素鋼、緞造鋼、ステンレス鋼、セラミックス等から造られ、研磨、クロムメッキ仕上げしたものが用いられる。
また、加圧成形における汚れを防ぐために、環境をクリ−ン化するとともに、改質ＰＴＦＥの室温転移（２０℃近傍）の影響を避けるために、２３〜２５℃に温度調整する必要がある。
次に、焼成工程において、加圧成形工程で得られた検出子本体２及び蓋部材６の予備成形品を焼成炉に移し、温度プロファイルとして、焼成温度３３０〜３９０〔℃〕で焼成し予備成形品を得る。
次に、切削工程において、焼成工程において焼成された予備成形品は一般用旋盤やＮＣ旋盤で切削加工され、バリ等を除去し、検出子本体２及び蓋部材６を所定の寸法に加工する。
次に、挿入工程において、前記焼成工程で得られた検出子本体２の収納部３にインサ−ト部材５が嵌挿される。
ここで、インサ−ト部材としては、流量計のインサ−ト部材が用いられ、具体的には、金属、セラミック、マグネット、合成樹脂等の１種類若しくは２種類以上が嵌挿される。
次に、装着工程において、インサ−ト部材５が嵌挿された検出子本体２に蓋部材６を熱融着して一体化するために、融着前処理として、蓋部材６の凸状周壁部６ｃを検出子本体２の開口部４に嵌合する。
【００２０】
次に蓋部材６と検出子本体２の嵌合状態を図面を用いて説明する。
図５は本発明の実施の形態における流量計の検出子の製造方法の装着工程における装着状態を示す要部断面図である。
図５において、検出子本体２、インサ−ト部材５、蓋部材６、凸部６ａ、蓋部材接合部６ｂ、凸部の周壁部６ｃについては図１乃至図３と同様であるので、同一の符号を付して説明を省略する。
図中、θ_１は検出子本体２の開口部４から外周に向けて下方に傾斜して形成された周壁部４ａの傾斜角度、θ_２は蓋部材６の凸部６ａの基部から外周に向けて上方に傾斜して形成された蓋部材接合部６ｂの傾斜角度、θは傾斜角度θ_１と傾斜角度θ_２とからなる開き角、Ｇは検出子本体２の開口部４と蓋部材６の蓋部材接合部６ｂの基部との間の間隙である。
検出子本体２の周壁部４ａと蓋部材６の蓋部材接合部６ｂは各々、傾斜角度θ_１とθ_２とからなる開き角θを有して形成され、検出子本体２と蓋部材６は間隙Ｇを有するように凸部の周壁部６ｃで開口部４に嵌合されている。
【００２１】
ここで、開き角θは０〜５〔ｄｅｇ〕となるように、加圧成形工程又は切削工程で形成され、隙間Ｇとして、流量計の検出子の長さＬに対する隙間Ｇの比Ｇ／Ｌが０〜１０％となるように嵌合される。
次に、熱融着工程において、蓋部材６の接合面積に応じて圧力０〜１０００〔ｇ／ｃｍ^２〕（蓋部材の自重をゼロとしている。）を加え、接合部分の温度が２５０〜３８０〔℃〕になるように加熱を行い検出子本体２と蓋部材６を熱融着により一体化する。
次に、後処理工程として、熱融着工程において融着された焼成品は切削加工され、バリ等の除去、及び所定の寸法に微調整され流量計の検出子１が形成される。
【００２２】
以上のように実施の形態における流量計の検出子は構成されているので、以下の作用を有する。
ａ．検出子本体と蓋部材を直接熱融着するため、従来のような開先部を溶接材で溶接する場合と異なり、接合面積を著しく広くできることから、接合強度を容易に高くすることができる。また、同一樹脂で直接各々の接合面を熱溶着するため、完全に一体化することができることから、接合部分にピンホ−ル等の発生がなく、従って外部の薬品等が内部に侵入することを防止することができるという作用を有する。尚、改質ＰＴＦＥを成分とする樹脂組成物を用いた場合も同様の作用を得ることができる。尚、成型条件は配合される樹脂に応じて多少変更される。
ｂ．蓋部材が凸部に周壁部を有するので、検出子本体と蓋部材との位置合わせ、仮止め等が容易にできる。また、凸部の周壁部が収納部の内壁と熱融着されることから接合面積を著しく増やすことができ、従来品に比べ接合強度を著しく強固にすることができるという作用を有する。
ｃ．開口部を有する収納部を備えた検出子本体を形成した後に、インサ−ト部材を挿入することから、検出子本体の所定の位置にインサ−ト部材を確実に保持できる。これにより、インサ−ト部材の位置ずれによる内部クラックの発生、不良品の発生等を抑えることができる。
ｄ．加圧及び加熱して熱融着する熱融着工程を有することにより、確実に接合部分の内側から接合でき、接合強度を高めることができるという作用を有する。ｅ．改質ＰＴＦＥの熱伝導の他、蓋部材と検出子本体との間隙を開けて装着し加熱するので、熱源からの放射熱により凸状周壁部に熱量が与えられ、検出子本体及び蓋部材の接合部分を略均一に加熱することができ凸状周壁部と収納部の内壁との間に融着斑が生じるのを防止できるという作用を有する。
ｆ．間隙を所定の長さにすることで、検出子本体と蓋部材の接合個所に肉の盛り上がり現象等を生ずることなく接合個所が目視で識別できないまでに完全に一体化できるという作用を有する。
ｇ．開き角を有することにより、検出子本体と蓋部材接合面の内側から外側に向かって順次熱融着されるので確実に全面接合されるため接合強度を著しく高めることができる。また、外観テストにより、接合斑の有無を容易に確認できる。また、傾斜を有することにより、外部に対して隙間を有し、改質ＰＴＦＥの熱伝導の他に、周囲の気体や、周囲の放射熱により短時間に接合部分の内部を加熱することができ、接合時間を著しく短縮することができ生産性を向上できるという作用を有する。
ｈ．改質ＰＴＦＥを用いたので、従来のＰＴＦＥに比べイオンの溶出を抑制できるという作用を有する。これは半導体ウェハ−の製造ライン等に極めて有効であることがわかった。
【００２３】
【実施例】
（実施例１〜３）
ａ．改質ＰＴＦＥとして、
ダイキン工業株式会社製ポリフロンＰＦＥモ−ルディングパウダ−（Ｍ−１１１）
ｂ．インサ−ト部材として、次の形状を有するステンレス製の円柱を用いた。
形状（１） φ３×Ｌ４０〔ｍｍ〕
（２） φ６×Ｌ２０〔ｍｍ〕
（３） φ１５×Ｌ１５〔ｍｍ〕
まず、改質ＰＴＦＥ粉末を金型に充填して、圧力２００〜４００〔ｋｇｆ／ｃｍ^２〕、加圧時間１〜１０〔ｍｉｎ〕で加圧成形をして検出子本体と蓋部材の予備成形品を作製した。次に、各予備成形品にトラップされた気体を放出させるために２４〔ｈ〕放置した。次に、予備成形品を焼成温度３４０〜３６０〔℃〕、キ−プ時間２〜５〔ｈ〕で焼成を行った。次に、旋盤加工により、開き角０．１〜０．５〔ｄｅｇ〕を有するように検出子本体と蓋部材とを加工し検出子本体の開口部の周壁部及び蓋部材の蓋部材接合部を形成した。次いで蓋部材の凸部を検出子本体の収納部に流量計の検出子の長さＬに対する間隙Ｇの比Ｇ／Ｌ０．１〜２％で嵌合し、圧力５０〜３００〔ｇ／ｃｍ^２〕、焼成温度３３０〔℃〕、キ−プ時間２〔ｈ〕で熱融着し次の形状を有するサンプルを作製した。
本発明の実施例の流量計の検出子〔単位：ｍｍ〕
試験片（１）：外径４／収納部内径３／凸部の周壁部深さ２
試験片（２）：外径１０／収納部内径６／凸部の周壁部深さ３
試験片（３）：外径２０／収納部内径１５／凸部の周壁部深さ５
【００２４】
（比較例４〜６）
比較例として、従来の溶接型の流量計の検出子を作製した。
原料として、従来のＰＴＦＥ（ダイキン工業（株）製Ｍ−１２）を用いて行った。溶接剤として市販の溶接用ディスパ−ジョン、溶接棒としてＰＦＡ溶接棒（東邦化成（株）製）を用いた。インサ−ト部材としては実施例１〜３と同一のものを用いた。
まず、実施例と略同一の条件で予備成形品を作製し、同時間放置した後、実施例と同一条件で焼成した。次いで溶接剤を充填する開先部を開き角９０°で形成し、溶接用ディスパ−ジョンの塗布を行った後、ＰＦＡを熱風溶接機を用いて溶接し、次の形状を有するサンプルを作製した。
比較例１の流量計の検出子〔単位：ｍｍ〕
試験片（４）：外径４／収納部内径３／開先部深さ０．２５
試験片（５）：外径１０／収納部内径６／開先部深さ１
試験片（６）：外径２０／収納部内径１５／開先部深さ２
※開先部の開き角９０〔ｄｅｇ〕
【００２５】
（比較例７〜９）
比較例として、従来の埋設型の流量計の検出子を用いた。
原料として、比較例４〜６で使用した原料を用いた。インサ−ト部材としては実施例１〜３と同一のものを用いた。
まず従来のＰＴＦＥを金型に３０〜７０％充填したのち、インサ−ト部材を入れる。その後金型に未充填分のＰＴＦＥを充填し、圧力２００〜４００〔ｋｇｆ／ｃｍ^２〕、加圧時間１〜１０〔ｍｉｎ〕、で加圧成形をして検出子本体と蓋部材の予備成型品を作製した。次に、予備成形体の気体を放出させるために２４ｈ放置した。
次いで実施例と同一の条件で焼成を行った。焼成終了後素子形状に加工を行った。
従来の埋設型の流量計の検出子〔単位：ｍｍ〕
試験片（７）：外径４１
試験片（８）：外径１０
試験片（９）：外径２０
【００２６】
次に、得られた試験片について次の評価を行った。
（評価項目）
（１）引っ張り試験（ＪＩＳＫ６８９１に準じた。サンプル数ｎ＝１０）
（２）ヒ−トサイクル試験（サンプル数ｎ＝２０）

（３）位置測定試験
各試験片製作後に、軸方向及び半径方向の位置ズレを測定。（サンプル数ｎ＝１０）
その評価結果を（表１）乃至（表３）に示した。
【表１】

【表２】

【表３】

【００２７】
まず、各々接合強度を測るため試験片（１）〜（６）について引っ張り試験をおこなった。（表１）は比較される試験片の引っ張り強度の実測値及び単位接合面積当たりの引っ張り強度を示している。
この（表１）から明らかなように、接合強度において、実施例品は比較例品に対し最低でも従来の約６〜１０倍の接合強度が得られ、また、単位接合面積当たりの場合においても、約２倍以上の強度が得られることがわかった。また、本発明の試験片は接合部分以外が切断されたのに対し、従来の試験片では、その約９割が接合部分による切断であった。
次に、接合部分の密封性を測るため、ヒ−トサイクル試験を行った。（表２）は比較される試験片の不良個数を示している。
この（表２）から明らかなように、本発明の試験片には不良がまったくなく耐久性に優れていることがわかった。
次に、インサ−ト部材の位置ズレを測るために、位置測定試験をおこなった。位置測定試験は、検出子を軸方向に平行な方向に切断し、内部のインサ−ト部材の所定の位置からのズレを測定子を用いて測定し、最大幅のズレを持ってズレの値とした。
（表３）は比較される試験片（１）〜（３）、及び試験片（７）〜（９）の位置ズレを示したものである。
この（表３）から明らかなように、本実施例では、本発明の試験片では位置ズレが０．０５〜０．１１〔ｍｍ〕であるのに対し、比較例では２．５〜８．５〔ｍｍ〕と約５０〜８０倍の位置ズレが発生していることがわかった。
【００２８】
（実施例１０〜１２）
ｃ．検出子本体：改質ＰＴＦＥとして、ダイキン工業株式会社製（Ｍ−１１１）
蓋部材：ＰＦＡとして、ダイキン工業株式会社製（ＡＰ２１１）
ｄ．インサ−ト部材：ステンレス製の円柱

改質ＰＴＦＥで形成された検出子本体の作製方法については、実施例１〜３と同様であるので、説明を省略する。
次に、ＰＦＡで形成された蓋部材の作製方法としては、
金型：φ３０×Ｌ７０（円柱状）
温度：３３０〜３８０℃
１サイクル：５分
の条件で射出成型後、旋盤等を行い、実施例１〜３と同様な熱融着条件等で試験片を作製した。
尚、試験片形状については以下のように、実施例１と同一形状とした。
本発明の実施例２の流量計の検出子〔単位：ｍｍ〕
試験片（１０）：外径４／収納部内径３／凸状周壁部深さ２
試験片（１１）：外径１０／収納部内径６／凸状周壁部深さ３
試験片（１２）：外径２０／収納部内径１５／凸状周壁部深さ５
【００２９】
（比較例１３〜１５）
比較例１３〜１５として、従来の溶接型の流量計の検出子を作製した。
原料として、検出子本体及び蓋部材ともにＰＦＡ（ダイキン工業製：ＡＰ２１１）を用いた。作製方法としては、
金型：φ３０×Ｌ７０（円柱状）
温度：３３０〜３８０℃
１サイクル：５分
の条件で射出成型後、旋盤等を行い、比較例４〜６と同様な溶接条件等で試験片を作製した。
尚、試験片形状については以下のように、比較例と同一形状とした。
比較例１の流量計の検出子〔単位：ｍｍ〕
試験片（１３）：外径４／収納部内径３／開先部深さ０．２５
試験片（１４）：外径１０／収納部内径６／開先部深さ１
試験片（１５）：外径２０／収納部内径１５／開先部深さ２
※開先部の開き角９０〔ｄｅｇ〕
【００３０】
次に、得られた試験片について実施例１〜３と同様に評価を行った。
その評価結果を（表４）乃至（表６）に示した。
【表４】

【表５】

【表６】

【００３１】
この（表４）から明らかなように、接合強度において、従来の約４〜７倍の接合強度が得られ、また、単位接合面積当たりの場合においても、約１．４倍の強度が得られることが分かる。
また、接合部分の密封性を測るため、ヒ−トサイクル試験を行った。（表５）は比較される試験片の不良個数を示している。
この（表５）から明らかなように、本発明の試験片には不良がまったくないことが分かる。
次に、インサ−ト部材の位置ズレを測るために、位置測定試験をおこなった。位置測定試験は、検出子を軸方向に平行な方向に切断し、内部のインサ−ト部材の所定の位置からのズレを測定子を用いて測定し、最大幅のズレを持ってズレの値とした。
（表６）は比較される試験片（１０）〜（１２）、及び試験片（１３）〜（１５）の位置ズレを示したものである。
この（表６）から明らかなように、本実施例では、軸方向の位置ズレが０．０９〜０．２５〔ｍｍ〕、半径方向の位置ズレが０．０５〜０．０８〔ｍｍ〕であるのに対し、比較例では軸方向で０．１〜０．２６〔ｍｍ〕、半径方向で０．０８〜０．１４〔ｍｍ〕と略同等の精度であることがわかった。
【００３２】
【発明の効果】
以上のように本発明によれば、以下の優れた効果を有する流量計の検出子及び流量計の検出子の製造方法を提供することができる。
本発明の請求項１に記載の流量計の検出子によれば、改質ＰＴＦＥ製の検出子本体と改質ＰＴＦＥ製の蓋部材を直接熱融着するため、接合面積を広くすることができることから、接合斑を防止できるとともに接合強度を容易に高くすることができ優れた接合性を得ることができる。また、直接溶融して接合するため、接合部が一体となり接合斑等、接合部分のピンホ−ル等の発生を防止することができることから、優れた信頼性、耐久性を得ることができる。
請求項２に記載の流量計の検出子によれば、請求項１に記載の発明の効果に加え、ＰＦＡを主成分とする樹脂組成物を用いた場合、接合強度を向上させることができる。
また、ＰＴＦＥを主成分とする樹脂組成物を用いた場合、熱融着時の保形性を向上させることができるとともにインサ−ト部材の位置決めをより正確にすることができる。
【００３３】
請求項３に記載の流量計の検出子によれば、請求項１又は２に記載の発明の効果に加えて、凸状周壁部を有することで、改質ＰＴＦＥ製の検出子本体と改質ＰＴＦＥ製の蓋部材との位置合わせ、仮止め等が容易にでき優れた作業性が得られる。また、凸状周壁部が開口部に嵌合されていることから接合面積が増加し、外部の薬品等が侵入する侵入経路が長くなるため、ピンホ−ル等による外部の薬品等の侵入を完全に防止することができるとともに、接合強度を著しく高くすることができ優れた信頼性、耐久性、及び接合性を得ることができる。
請求項４に記載の流量計の検出子によれば、請求項１又は２に記載の発明の効果に加えて、接合面を拡大し接合性を高めるとともに、より強固な接合強度を得ることができる。
請求項５に記載の流量計の検出子によれば、請求項３又は４に記載の発明の効果に加えて、開き角を備えているので、熱溶融時に収納部内の空気を逃散させ接合面に空気孔等の生成を防止でき優れた信頼性、及び耐久性を得ることができる。
【００３４】
請求項６に記載の流量計の検出子の製造方法によれば、開口部を有する収納部を備えた改質ＰＴＦＥ製の検出子本体を形成した後に、インサ−ト部材を挿入することから、改質ＰＴＦＥ製の検出子本体の所定位置にインサ−ト部材を確実に挿入できインサ−ト部材の位置ズレを防止できるとともに、インサ−ト部材の位置ズレによる強度の低下、ピンホ−ルの発生、歩留りの低下等を抑えることができ信頼性に優れるとともに高い生産性を得ることができる。
請求項７に記載の流量計の検出子によれば、請求項６に記載の発明の効果に加え、改質ＰＴＦＥ製の検出子本体とＰＦＡを主成分とする蓋部材を熱融着した場合、熱処理時の樹脂の流動性が向上するため、熱処理時間の短縮が可能となり、生産性を向上させ省エネルギー性を高めることができる。また検出子を二次加工する場合、他部品との接合処理の効率を向上させることができる。また改質ＰＴＦＥ製の検出子本体とＰＴＦＥを主成分とする蓋部材を熱融着した場合、熱処理時の保形性が向上するため、インサ−トされた芯材のズレを減少させることができ高精度の検出子を得ることができる。
請求項８に記載の流量計の検出子の製造方法によれば、請求項６又は７に記載の発明の効果に加えて、蓋部材と検出子本体との間隙を直に加熱するので、検出子本体及び蓋部材の接合部分を容易に加熱することができるので未熟練者でも確実に接合できるとともに優れた接合性を得ることができる。また、隙間を所定の長さにすることで、インサ−ト部材と収納部の内壁との間に隙間を生じさせることなく、所定の位置にインサ−ト部材を配置させ、かつ接合面の状態を外観から確定できないレベル（２００倍の顕微鏡観察においても接合カ所が確定困難なレベル）まで、均質接合ができ品質を向上できる。
【００３５】
請求項９に記載の流量計の検出子の製造方法によれば、請求項６乃至８の内いずれか１項に記載の発明の効果に加えて、検出子本体の周壁部と蓋部材接合部が内側から外側に向かって確実に全面接合されるため接合強度を安定に確実に得られ優れた接合性を得られる。また、開き角を有することにより、接合部の露出面を速やかに加熱することができ優れた生産性が得られる。
請求項１０に記載の流量計の検出子の製造方法によれば、請求項７乃至９に記載の発明の効果に加え、多種多様なサイズ・形状の検出子に対して、熱融着処理工程に使用する治工具の汎用性が向上し、コストの低減化を図ることができる。また、熱処理時間の短縮が可能となり、生産性を上げるとともに省エネルギー性を向上させることができる。更に、熱融着処理に精通していない作業者でも短時間で、作業内容を理解することが可能で作業性を向上させるとともに生産性を向上させることができる。
請求項１１に記載の流量計の検出子の製造方法によれば、請求項１０に記載の発明の効果に加えて、検出子本体と蓋部材とを確実に融着することができ優れた高品質の検出子を高い生産性で得ることができる。
【図面の簡単な説明】
【図１】本発明の実施の形態における流量計の検出子の分解斜視図
【図２】本発明の実施の形態におえる流量計の検出子の透視斜視図
【図３】本発明の実施の形態における流量計の検出子の要部断面図
【図４】図３のＡ部の拡大図
【図５】本発明の実施の形態における流量計の検出子の製造方法の装着工程における装着状態を示す要部断面図
【図６】従来の流量計の検出子の分解図
【図７】従来の流量計の検出子の透視斜視図
【図８】従来の流量計の検出子の縦断面図
【図９】図８のＢ部の拡大図
【図１０】（ａ）従来の埋設型の流量計の検出子の透視斜視図
（ｂ）従来の埋設型の流量計の検出子の透視斜視図
【符号の説明】
１流量計の検出子
２検出子本体
３収納部
４開口部
４ａ周壁部
５インサ−ト部材
６蓋部材
６ａ凸部
６ｂ蓋部材接合部
６ｃ凸状周壁部
７熱融着部
７ａ凸部熱融着部
５１従来のＰＴＦＥ製の流量計の検出子
５２検出子本体
５３インサ−ト部材収納部
５４開口部
５５当接面
５６開先部
５７蓋部材
５８当接面
５９開先部
６０凸部
６１インサ−ト部材
７０溶接剤
７１溶接面
７２未シ−ル部
８０従来の埋設型検出子
８１検出子本体
８２ａ、８２ｂインサ−ト部材[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flow meter detector and a method for manufacturing the same.
[0002]
[Prior art]
In recent years, domestic production of fluororesin has increased rapidly due to the development of the semiconductor industry, automobile industry, or various precision machine industries, with an annual growth rate of 10,000 tons / year, and an annual growth rate of 10%. This is due to the excellent chemical, electrical and thermal properties of the fluororesin. Among them, polytetrafluoroethylene (hereinafter referred to as PTFE) has unique properties such as chemical resistance, heat resistance, cold resistance, abrasion resistance, non-adhesion, and electrical properties such as low dielectric constant. However, there is no other material with a good balance of properties.
Many flowmeter detectors have been proposed by utilizing the properties of PTFE such as chemical resistance. For example, it is disclosed in JP-A-62-63819, JP-A-61-80422, JP-A-5-77727, JP-A-6-23143, and JP-A-7-18976.
Hereinafter, the detector of the conventional flowmeter will be described with reference to the drawings.
FIG. 6 is an exploded view of the detector of the conventional flow meter, FIG. 7 is a see-through perspective view of the detector of the conventional flow meter, and FIG. 8 is a longitudinal sectional view of the detector of the conventional flow meter. FIG. 9 is an enlarged view of a portion B in FIG.
In FIG. 6, reference numeral 51 denotes a detector of a conventional PTFE flowmeter; 52, a detector main body having a conical lower portion; and 53, an insert formed coaxially with a shaft portion of the detector main body 52. A member storage portion, 54 is an opening of the insert

member storage portion

53, 55 is a contact surface of the peripheral wall surrounding the opening 54 with the lid member, and 56 is an opening formed around the contact surface 55. A tip portion, 57 is a lid member, 58 is a contact surface of the

lid member

57, 59 is a groove portion formed symmetrically with the groove portion 56 around the outer periphery of the

contact surface

58, and 60 is a lower surface of the lid member 57. Reference numeral 61 denotes an insert member formed coaxially.
7 to 9, reference numeral 70 denotes a welding material such as PFA filled and welded between the groove portion 56 and the groove portion 59; 71, a welding surface between the

groove portions

56, 59 and the welding material 70; It is an unsealed part.
[0003]
Hereinafter, a method of manufacturing the detector of the conventional flowmeter configured as described above will be described.
First, in a first step, a predetermined amount of PTFE powder is pressure-molded to form a pressure-molded product of the detector main body 52 and the lid member 57.
Next, in the second step, the preformed product of the detector main body 52 and the lid member 57 obtained in the first step is transferred to a firing furnace and fired to obtain a preformed product.
Next, in the third step, the preformed product obtained in the second step is subjected to removal of burrs and the like, and is subjected to primary processing to a predetermined size. Further, in order to join the detector main body 52 and the lid member 57,

groove portions

56 and 59 are formed in a V-shape respectively.
Next, in a fourth step, a surface treatment such as cleaning and drying these welding surfaces with a cleaning agent is performed.
Next, in a fifth step, the insert member 61 is inserted into the insert member storage portion 53 of the detector main body 52 obtained in the fourth step.
Next, in a sixth step, a welding chemical is applied to the welding surfaces of the detector main body 52 and the lid member 57 in which the insert members 61 are inserted.
Next, as a seventh step, the convex portion 60 of the lid member 57 is inserted into the detector main body 52, and the

contact surfaces

55 and 58 are joined. Next, as an eighth step, a welding rod made of a fluororesin, such as tetrafluoroethylene-perfluoroalkylvinyl ether polymer (hereinafter, referred to as PFA), is used as a welding material in the

groove portions

56, 59 using a heater or the like. Welds the

groove portions

56 and 59 while heating them one by one.
Next, in a ninth step, the detector of the flowmeter welded in the eighth step is cooled down. This is because if the cooling is not performed, the welded portion will be peeled off due to the difference in the coefficient of thermal expansion between PTFE and PFA.
Next, in a tenth step, the fired product of the welded portion and the like is cut, the burrs and the like are removed, and the dimensions and the like are finely adjusted to form the detector 11 of the flow meter.
[0004]
In addition, there is a detector of an embedded type flow meter manufactured by embedding an insert member in PTFE powder, press-molding, and firing a compact obtained by press-molding.
FIGS. 10A and 10B are perspective perspective views of a detector of a conventional buried type flow meter. Reference numeral 80 denotes a conventional embedded detector, 81 denotes a detector main body, and 82a and 82b denote embedded insert members.
When the insert members 82a and 82b are buried in the PTFE powder and press-molded, unevenness occurs when filling the PTFE powder or when the insert member is buried. Some parts were exposed on the peripheral wall surface, etc., deviating left and right from the central axis, or inclined.
[0005]
[Problems to be solved by the invention]
However, the detector of the conventional flowmeter has the following problems.
a. There was a problem that the bonding strength was low due to the small bonding area and the durability was poor.
b. Further, there is a problem that PFA piled up around the groove is peeled off during cutting with a lathe or the like, and the product yield is low.
c. Further, there was a problem that PFA of the welding agent was peeled off during use in the flow meter due to low bonding strength.
d. Since the joining area is small and welding spots are apt to occur, there is a problem that the sealing material is lacking, and an external chemical or the like invades the inside by a pinhole or the like and corrodes the insert member or the like.
e. The embedded type flowmeter has a problem in that the position of the insert member is not stabilized during processing, and the product is eccentric and the product yield is low.
f. In some cases, the thickness of the side wall of the storage portion of the insert member becomes extremely thin, and the strength becomes unstable. In addition, an external chemical or the like enters the inside by a pinhole or the like and corrodes the insert member. There was a problem such as making it.
g. PTFE is difficult to weld, so after processing as a "detection element", it is extremely difficult to join with other parts even if you try to combine with other parts to improve the functionality by combining with other parts. There is a problem that the secondary workability for improving the workability is lacking.
h. At the time of manufacturing a semiconductor wafer, a flow meter detector made of PTFE has a problem in that ions may be eluted in a solvent and lacks versatility.
[0006]
SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and detects a flow meter which has a high joining strength, does not generate pinholes, can fix an insert member at a predetermined position, and can measure a flow rate with high accuracy. Providing a high quality flowmeter with high bonding strength, high durability, easy insertion of the insert member in a predetermined position, excellent production workability and productivity, and high quality flowmeter detector It is an object of the present invention to provide a method for manufacturing a detector of a flow meter which can be produced in a yield.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a flowmeter detector and a method of manufacturing the flowmeter detector according to the present invention include the following means.
According to a first aspect of the present invention, there is provided a detector of a flowmeter, comprising: a detector main body having a storage portion having an opening; an insert member inserted into the storage portion; and an opening of the detector main body. And a lid member that is integrated with the detector main body by heat fusion so as to cover the peripheral wall portion including at least one of the detector main body and the lid member, wherein at least one of the detector main body and the lid member is modified PTFE or a modified PTFE. It has a configuration formed of a resin composition containing high quality PTFE as a main component.
As a result, since the detector body made of modified PTFE and the lid member made of modified PTFE are directly heat-sealed, unlike the case where the groove is joined with a welding material, the joining area can be increased, so that the joining spots can be reduced. It is possible to prevent this and to easily increase the bonding strength. In addition, since the same resin is directly melted and joined, the joined portions are united to prevent the occurrence of uneven spots and the like, and have the effect of preventing the occurrence of pinholes and the like at the joined portions.
Here, as the modified PTFE, at least one of perfluoroethers represented by the following chemical formulas (Chemical Formula 1), (Chemical Formula 2), and (Chemical Formula 3) is used as a modifier during suspension polymerization. PTFE that has been added and polymerized is used.
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Specifically, a molding powder (M-111, M-112, M-137) (trade name, manufactured by Daikin Industries, Ltd.), a product manufactured by Hoechst, and the like are used.
PFA, PTFE and the like can be mentioned as other synthetic resins to be blended as the composition.
By adding PFA, the time required for heat fusion can be reduced, and the cost can be reduced. In addition, the addition of conventional PTFE can improve the shape retention during heat fusion and can be used as a diluent to reduce cost.
The amount of PFA is 1 wt% to 95 wt%, preferably 1 wt% to 80 wt%. If the amount is less than 1 wt%, the effect of addition is difficult to be recognized, and if the amount is more than 80 wt%, the shape retention during heat fusion is reduced, and the core of the insert member is likely to be displaced. .
Conventional PTFE is used in an amount of 1 wt% to 90 wt%, preferably 1 wt% to 70 wt%. If the amount is less than 1% by weight, the effect of the addition is hard to be recognized, and if the amount is more than 70% by weight, a tendency that the joining strength tends to be lowered is unpreferably exhibited.
[0008]
In the detector of the flow meter according to claim 2 of the present invention, in claim 1, any one of the detector main body and the lid member mainly includes any one of conventional PTFE and PFA. It has a configuration formed of a resin composition.
Thus, when a conventional resin composition containing PTFE as a main component is used, the shape retention during heat fusion is improved, and the insert member can be positioned more accurately.
In addition, when a resin composition containing PFA as a main component is used, the processing time during heat fusion can be reduced, which is effective in reducing costs. Has the effect of improving the efficiency of the welding process.
[0009]
The detector of the flow meter according to claim 3 of the present invention, in the invention according to

claim

1 or 2, wherein the lid member has a ring-shaped or column-shaped projection fitted to the opening at the center of the bottom surface. Part, the lid member, a ring-shaped or column-shaped convex part fitted to the opening part at the bottom center part, a peripheral wall part of the convex part joined to a peripheral wall of the storage part, A lid member joining portion which is joined to the peripheral wall of the opening around the periphery, wherein the lid member has a peripheral wall portion of the convex portion and an inner wall of the housing portion of the detector main body and the opening at the lid member joining portion; It has a configuration in which the peripheral wall is heat-sealed and integrated.
Thereby, since the lid member has the peripheral wall portion of the convex portion, the positioning of the detector main body and the lid member, the temporary fixing, and the like can be easily performed. In addition, since the convex peripheral wall is fitted into the opening, the joining area increases, and the invasion path of the external chemicals or the like becomes longer, so that the intrusion of the external chemicals or the like by the pinhole or the like is completely prevented. It is possible to prevent such a problem and to significantly increase the bonding strength.
Here, as the peripheral wall portion of the convex portion, the surface may be smooth, but in order to impart an anchoring effect and increase the bonding area and increase the bonding strength, a thread may be thread-cut or an uneven portion may be provided. .
[0010]
According to a fourth aspect of the present invention, there is provided the flowmeter detector according to the first or second aspect, wherein the lid member has a coaxial bulge protruding toward the joint surface side or a concave recessed inward. A lid member joining portion formed of a curved surface portion, wherein an opening peripheral wall of the detector main body is formed by an inclined surface which comes into contact with a bulging portion or a concave curved surface portion of the lid member, and the lid member is attached to the lid member joining portion; In this case, the detector body is thermally fused and integrated with the peripheral wall of the opening.
This has the effect of enlarging the joint surface and obtaining a stronger joint strength.
[0011]
In the detector of the flow meter according to claim 5 of the present invention, in the invention according to

claim

3 or 4, the facing surface between the peripheral wall of the opening and the joint portion of the lid member has an opening angle of 0 ° to 5 °, preferably. Has a configuration formed at 0.1 ° to 3 °, more preferably 0.2 ° to 3 °.
With this configuration, the opening angle is provided, so that the air in the storage section can escape at the time of thermal melting, and the formation of air holes or the like at the joint surface can be prevented.
Here, as the opening angle becomes smaller than 0.2 °, a tendency that gas tends to remain in the storage portion tends to appear, and as the opening angle becomes larger than 3 °, the joining strength decreases and the airtightness (sealing) decreases. ) Are not preferred, since the tendency of lowering of the property easily occurs.
[0012]
The method for manufacturing a detector of a flow meter according to claim 6 of the present invention is characterized in that a storage section having an opening is formed by pressure-molding powder of a modified PTFE or a resin composition containing the modified PTFE as a main component. A pressure forming step of forming a lid member having a detector body provided and a lid member joining portion fitted or abutted on the opening, and the detector body and the lid obtained in the pressure molding step A firing step of firing the member, an insertion step of inserting an insert member into the storage portion of the detector main body obtained in the firing step, and a step of inserting the insert member into the detector main body. A mounting step of mounting the lid member in the opening and / or the storage section; and 0 <P <2400 [g / cm in terms of pressure on the lid member mounted in the mounting step. ² ], Preferably 30 ≦ P ≦ 1000 [g / cm ² And a heat fusion step of performing heat fusion by applying heat while applying stress.
Thus, the insert member is inserted after forming the detector main body having the storage portion having the opening, so that the insert member can be reliably inserted into a predetermined position of the detector main body. The displacement of the members can be prevented, and a decrease in strength due to a displacement of the insert member, the occurrence of internal cracks, a decrease in yield, and the like can be suppressed. In addition, by having a heat fusion step of fusing under pressure, it is possible to suppress the elongation of the detector main body in the axial direction and to assure reliable bonding from the inside, increase the bonding strength and join the detector main body and the lid. Variations in strength can be reduced.
[0013]
The method for manufacturing a detector of a flowmeter according to claim 7 of the present invention is the method of claim 6, wherein in the pressing step, the powder of any one of the detector main body and the lid member is used. It has a structure formed of any one of PTFE and PFA or a resin composition containing one of these as a main component.
As a result, when a resin containing PTFE as a main component is used, the shape retention at the time of heat fusion is improved, and the positioning of the insert member can be more accurately performed.
Further, when a resin composition containing PFA as a main component is used, it has the effect that the processing time during heat fusion can be reduced.
[0014]
In the method for manufacturing a detector of a flowmeter according to claim 8, in the invention according to

claim

6 or 7, in the mounting step, the lid member is fitted and mounted in a storage portion of the detector main body. A gap G between the cover member joining portion of the cover member and the peripheral wall of the opening of the detector main body, wherein G / L is 0 ≦ G / L ≦ 10% with respect to the entire length L of the detector. , Preferably 0.1 ≦ G / L ≦ 5%.
In this way, in addition to the heat conduction of the modified PTFE, the gap between the lid member made of the modified PTFE and the detector body made of the modified PTFE, and the heat conduction from the surrounding gas and the heat radiation from the surroundings. And the joint between the modified PTFE detector body and the modified PTFE lid member can be easily heated, so that the joint can be surely made.
In addition, by setting the gap to a predetermined length, it is possible to completely integrate the joining portion between the detector main body and the lid member without visually increasing the joining portion without causing a bulging phenomenon or the like at the joining portion.
Here, if the ratio G / L is smaller than 0.1%, there is a tendency that a gap is easily formed between the insert member and the detector main body, and the ratio G / L is larger than 8%. In such a case, there is a tendency that the joining strength is reduced and a joining line is apt to be generated, so that both are not preferable.
[0015]
According to a ninth aspect of the present invention, in the method for manufacturing a detector of a flow meter according to any one of the sixth to eighth aspects, an opening angle θ between the lid member joint and the opening peripheral wall is 0. ° <θ <5 °, preferably 0.2 ≦ θ ≦ 3 °. As a result, the peripheral wall portion of the detector body made of the modified PTFE and the joining surface of the lid member made of the modified PTFE are joined from the inside to the outside by heating and pressurization, and the entire surface is securely joined. And it is surely obtained. Further, with this configuration, the bonding state can be easily confirmed at the time of the appearance test. In addition, by having the opening angle, in addition to the heat conduction of the modified PTFE, the joining portion can be quickly heated by the surrounding gas or the surrounding radiant heat.
Here, when the opening angle θ is smaller than 0.2 °, although it depends on the weight pressure, an unjoined portion is easily generated inside the joined portion, so that there is a danger of a decrease in joining strength and leakage. When the opening angle θ is larger than 3 °, an unjoined portion is easily generated outside the joined portion, so that the risk of a decrease in joining strength and leakage increases, and the joining portion is increased. Any of these is not preferred because they tend to appear and lack impact resistance.
[0016]
According to a tenth aspect of the present invention, in the method for manufacturing a detector of the flow meter according to any one of the sixth to ninth aspects, in the heat fusion step, the area of the fusion portion is S [cm ² ], When the total length of the flow meter is L [cm], the stress applied at the time of heat fusion is a pressure P [g / cm]. ² ], The following formula is satisfied.
P = A (T) × (S / L) + B (T)
Here, A (T) is A (T) = − 1.13T + α, B (T) = − 0.454T + β, α = 780 to 850, β = 310 to 380, and α and β are the type and amount of resin. Is a constant determined by, T is the absolute temperature (K). Specifically, in the case of modified PTFE, α = 816 ± 10 and β = 345 ± 10 are used.
As a result, it is possible to select an arbitrary applied stress to some extent on the unprocessed element before performing the heat fusion processing. As a result, the versatility of jigs and tools used in the heat fusion processing step is improved for unprocessed elements having various sizes and shapes, and a cost merit is obtained. In addition, it is possible to quickly respond to an element having a special shape. In addition, since an arbitrary processing temperature can be selected to some extent, the heat treatment time can be reduced.
[0017]
According to a method for manufacturing a detector of a flow meter according to an eleventh aspect, in the invention according to the tenth aspect, in the heat-sealing step, the applied stress is converted into a pressure P by 0 <P <2400 [g / cm ² ], Preferably 30 ≦ P ≦ 1000 [g / cm ² ], And the heating temperature T is 250 <T <450 [° C], preferably 320 ≦ T ≦ 390 [° C].
Thereby, the detector body made of the modified PTFE and the lid member made of the modified PTFE can be reliably fused.
Here, when the pressure P is smaller than 30, a tendency that an unbonded portion is easily generated occurs, and the pressure P is 1000 [g / cm]. ² ], There is a tendency that the deformation of the detector and the displacement of the insert member tend to occur.
When the temperature T is lower than 320 ° C., the unbonded portion tends to be easily generated, and when the temperature T is higher than 390 ° C., the synthetic resin is deteriorated and the mechanical strength is easily lowered. Either is not preferred because of the tendency.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is an exploded perspective view of a detector of a flow meter according to an embodiment of the present invention, FIG. 2 is a transparent perspective view of a detector of the flow meter according to an embodiment of the present invention, and FIG. FIG. 4 is a sectional view of a main part of a detector of the flow meter according to the embodiment, and FIG. 4 is an enlarged view of a portion A in FIG.
In FIG. 1, reference numeral 1 denotes a detector of a flow meter made of modified PTFE, and 2 denotes a detector made of modified PTFE having a storage portion having an opening formed coaxially and a lower portion formed in a conical shape. The main body 3 has a storage section formed coaxially with the detector body 2 made of modified PTFE, 4 has an opening formed on the upper surface of the

storage section

3, 4 a has a peripheral wall of the

opening

4, and 5 has an opening 4. An insert member fitted into the storage portion 3 from above, 6 is a lid member made of modified PTFE joined to the detector body 2 made of modified PTFE, and 6a is coaxial with the joint surface side of the lid member 6. The formed convex portion, 6b is a lid member joining portion surrounding the convex portion 6a joined to the peripheral wall portion 4a of the opening 4 of the detector

main body

2, and 6c is a peripheral wall of the convex portion 6a fitted to the opening portion 4. Department.
2 to 4, reference numeral 7 denotes a heat-sealed portion between the detector main body 2 and the

cover member

6, and 7a denotes a convex heat-sealed portion.
[0019]
Hereinafter, a method of manufacturing the detector of the flowmeter according to the embodiment configured as described above will be described.
First, in a pressure molding step, the modified PTFE raw material powder is charged into a predetermined mold for molding a preformed product of the detector body 2 made of the modified PTFE and the lid member 6 made of the modified PTFE, and a hydraulic pressure is applied. 200 to 600 [kgf / cm ² ] To pressurize the modified PTFE raw material powder to produce a preform. At this time, the pressure is maintained for 1 to 180 [min] in order to release gas existing between the modified PTFE raw material powders which causes voids and cracks. The formed preform is taken out of the mold and left at room temperature for several minutes to several days to release the gas trapped inside again.
The mold used here is made of carbon steel, rolled steel, stainless steel, ceramics, or the like, and is polished and chrome-plated.
In addition, it is necessary to clean the environment in order to prevent stains during pressure molding, and to adjust the temperature to 23 to 25 ° C. in order to avoid the influence of the room temperature transition (around 20 ° C.) of the modified PTFE.
Next, in the firing step, the preformed product of the detector main body 2 and the lid member 6 obtained in the pressure forming step is transferred to a firing furnace, and fired at a firing temperature of 330 to 390 [° C.] as a temperature profile. Get the goods.
Next, in the cutting step, the preformed article fired in the firing step is cut by a general-purpose lathe or an NC lathe to remove burrs and the like, and to process the detector main body 2 and the lid member 6 to predetermined dimensions.
Next, in an insertion step, an insert member 5 is inserted into the storage section 3 of the detector main body 2 obtained in the firing step.
Here, as the insert member, an insert member of a flow meter is used, and specifically, one or more types of metal, ceramic, magnet, synthetic resin, etc. are inserted.
Next, in a mounting process, in order to integrate the lid member 6 by heat fusion with the detector main body 2 in which the insert member 5 is fitted and inserted, as a pre-fusion process, a convex peripheral wall of the lid member 6 is used. The portion 6c is fitted into the opening 4 of the detector main body 2.
[0020]
Next, the fitted state of the lid member 6 and the detector main body 2 will be described with reference to the drawings.
FIG. 5 is a fragmentary cross-sectional view showing a mounting state in a mounting step of the method for manufacturing the detector of the flowmeter according to the embodiment of the present invention.
In FIG. 5, the detector main body 2, insert member 5, lid member 6, convex portion 6a, lid member joining portion 6b, and peripheral wall portion 6c of the convex portion are the same as those in FIGS. The description is omitted by attaching the reference numerals.
In the figure, θ ₁ Is the inclination angle of the peripheral wall portion 4a formed to be inclined downward from the opening 4 of the detector main body 2 toward the outer periphery, θ ₂ Is the inclination angle of the lid member joining portion 6b formed by inclining upward from the base of the convex portion 6a of the lid member 6 toward the outer periphery, and θ is the inclination angle θ. ₁ And inclination angle θ ₂ And G is the gap between the opening 4 of the detector main body 2 and the base of the lid member joint 6b of the lid member 6.
The peripheral wall portion 4a of the detector main body 2 and the lid member joining portion 6b of the lid member 6 are each provided with an inclination angle θ. ₁ And θ ₂ The detector main body 2 and the cover member 6 are fitted into the opening 4 at the peripheral wall 6c of the projection so as to have a gap G.
[0021]
Here, the opening angle θ is formed in a pressure forming step or a cutting step so as to be 0 to 5 [deg]. As the gap G, a ratio G / L of the gap G to the length L of the detector of the flow meter is used. Are fitted so as to be 0 to 10%.
Next, in the heat fusion step, the pressure is 0 to 1000 [g / cm] depending on the bonding area of the lid member 6. ² (The weight of the lid member is set to zero), and heating is performed so that the temperature of the joining portion becomes 250 to 380 ° C., and the detector main body 2 and the lid member 6 are integrated by heat fusion.
Next, as a post-processing step, the fired product fused in the heat fusion step is cut to remove burrs and the like, and finely adjusted to a predetermined size to form the detector 1 of the flow meter.
[0022]
Since the detector of the flow meter according to the embodiment is configured as described above, it has the following operation.
a. Since the detector main body and the lid member are directly heat-sealed, unlike the conventional case where the groove is welded with a welding material, the joining area can be significantly increased, so that the joining strength can be easily increased. In addition, since the joint surfaces are directly heat-welded with the same resin, they can be completely integrated, so that there is no generation of pinholes or the like at the joint portions, and therefore, it is possible to prevent external chemicals or the like from entering the inside. It has the effect that it can be prevented. The same effect can be obtained when a resin composition containing modified PTFE as a component is used. The molding conditions are slightly changed depending on the resin to be mixed.
b. Since the lid member has the peripheral wall portion on the convex portion, the positioning between the detector main body and the lid member, temporary fixing, and the like can be easily performed. Further, since the peripheral wall portion of the projection is thermally fused to the inner wall of the storage portion, the bonding area can be significantly increased, and the bonding strength can be significantly increased as compared with the conventional product.
c. After the insertion of the insert member after the formation of the detector main body having the storage portion having the opening, the insert member can be reliably held at a predetermined position of the detector main body. As a result, it is possible to suppress the occurrence of internal cracks and defective products due to the displacement of the insert member.
d. By having the heat fusion step of performing heat fusion by pressurizing and heating, it is possible to surely join from the inside of the joining portion and to increase the joining strength. e. In addition to the heat conduction of the modified PTFE, the lid member and the detector main body are attached and heated by opening the gap between the lid member and the detector main body. This has an effect that the joint portion can be heated substantially uniformly, and the occurrence of fusion spots between the convex peripheral wall portion and the inner wall of the storage portion can be prevented.
f. By setting the gap to a predetermined length, there is an effect that the joint can be completely integrated before the joint can not be visually identified without occurrence of a bulging phenomenon at the joint between the detector main body and the lid member.
g. By having an opening angle, the detector main body and the lid member are heat-sealed sequentially from the inside to the outside of the joining surface, so that the entire surface is securely joined, so that the joining strength can be significantly increased. In addition, the presence or absence of joint spots can be easily confirmed by an appearance test. In addition, by having a slope, there is a gap to the outside, and in addition to the heat conduction of the modified PTFE, the inside of the joint can be heated in a short time by the surrounding gas or the surrounding radiant heat. This has the effect of significantly reducing the joining time and improving the productivity.
h. Since modified PTFE is used, it has an effect that elution of ions can be suppressed as compared with conventional PTFE. This was found to be extremely effective for a semiconductor wafer production line and the like.
[0023]
【Example】
(Examples 1 to 3)
a. As modified PTFE,
Daikin Industries, Ltd. Polyflon PFE Molding Powder (M-111)
b. A stainless steel cylinder having the following shape was used as the insert member.
Shape (1) φ3 × L40 [mm]
(2) φ6 × L20 [mm]
(3) φ15 × L15 [mm]
First, a mold is filled with the modified PTFE powder, and the pressure is 200 to 400 [kgf / cm. ² ], And press-molded for a pressurization time of 1 to 10 [min] to prepare a preform of the detector main body and the lid member. Next, it was left for 24 hours to release the gas trapped in each preform. Next, the preform was fired at a firing temperature of 340 to 360 ° C and a keeping time of 2 to 5 hours. Next, the detector main body and the lid member are processed to have an opening angle of 0.1 to 0.5 [deg] by lathe processing, and the peripheral wall portion of the opening of the detector main body and the lid member joining portion of the lid member are processed. Was formed. Next, the convex portion of the lid member is fitted into the storage portion of the detector main body at a ratio G / L of the gap G to the length L of the detector of the flow meter of 0.1 to 2%, and a pressure of 50 to 300 g / cm. ² Then, the sample was heat-fused at a firing temperature of 330 ° C. and a keeping time of 2 hours to produce a sample having the following shape.
Detector of flow meter according to the embodiment of the present invention [unit: mm]
Test piece (1): outer diameter 4 / storage part inner diameter 3 / projection wall depth 2
Test piece (2): outer diameter 10 / storage part inner diameter 6 / surrounding wall depth of the convex part 3
Test piece (3): outer diameter 20 / storage part inner diameter 15 / surrounding wall depth 5
[0024]
(Comparative Examples 4 to 6)
As a comparative example, a detector of a conventional welding type flowmeter was manufactured.
This was performed using conventional PTFE (M-12 manufactured by Daikin Industries, Ltd.) as a raw material. A commercially available welding dispersion was used as a welding agent, and a PFA welding rod (manufactured by Toho Kasei Co., Ltd.) was used as a welding rod. The same insert member as in Examples 1 to 3 was used.
First, a preform was prepared under substantially the same conditions as in the example, left for the same time, and then fired under the same conditions as the example. Next, a groove for filling with a welding agent was formed at an opening angle of 90 °, and after applying a welding dispersion, PFA was welded using a hot-air welding machine to produce a sample having the following shape. .
Detector of flow meter of Comparative Example 1 [unit: mm]
Test piece (4): outer diameter 4 / storage inner diameter 3 / groove depth 0.25
Test piece (5): outer diameter 10 / storage inner diameter 6 / groove depth 1
Test piece (6): outer diameter 20 / storage part inner diameter 15 / groove depth 2
※ Opening angle of groove part 90 [deg]
[0025]
(Comparative Examples 7 to 9)
As a comparative example, a detector of a conventional buried type flow meter was used.
The raw materials used in Comparative Examples 4 to 6 were used as the raw materials. The same insert member as in Examples 1 to 3 was used.
First, the mold is filled with conventional PTFE by 30 to 70%, and then an insert member is inserted. Thereafter, the mold is filled with unfilled PTFE, and the pressure is 200 to 400 [kgf / cm]. ² ], And a press molding was performed for a pressurizing time of 1 to 10 [min] to prepare a preformed product of the detector main body and the lid member. Next, the preform was left for 24 hours to release the gas.
Next, firing was performed under the same conditions as in the example. After the completion of firing, processing was performed into an element shape.
Detector of conventional buried type flow meter [unit: mm]
Test piece (7): Outer diameter 41
Test piece (8): outer diameter 10
Test piece (9): Outer diameter 20
[0026]
Next, the following evaluation was performed about the obtained test piece.
(Evaluation item)
(1) Tensile test (according to JIS K6891; number of samples n = 10)
(2) Heat cycle test (number of samples n = 20)

(3) Position measurement test
After manufacturing each test piece, the displacement in the axial and radial directions was measured. (Number of samples n = 10)
The evaluation results are shown in (Table 1) to (Table 3).
[Table 1]

[Table 2]

[Table 3]

[0027]
First, a tensile test was performed on each of the test pieces (1) to (6) to measure the bonding strength. Table 1 shows the measured tensile strength and the tensile strength per unit bonding area of the test pieces to be compared.
As is clear from Table 1, the bonding strength of the example product is at least about 6 to 10 times higher than that of the comparative product in comparison with the comparative product, and even in the case of the unit bonding area. , About twice or more strength was obtained. In addition, the test piece of the present invention was cut at a portion other than the joint portion, whereas about 90% of the conventional test piece was cut by the joint portion.
Next, a heat cycle test was performed to measure the sealing performance of the joint. Table 2 shows the number of defective test pieces to be compared.
As is clear from Table 2 above, it was found that the test piece of the present invention had no defect and had excellent durability.
Next, a position measurement test was performed to measure the position deviation of the insert member. In the position measurement test, the detector is cut in a direction parallel to the axial direction, the displacement of the internal insert member from a predetermined position is measured using the probe, and the displacement value having the maximum width displacement is measured. And
Table 3 shows the displacement of the test pieces (1) to (3) and the test pieces (7) to (9) to be compared.
As is evident from Table 3 above, in the present example, the positional deviation of the test piece of the present invention was 0.05 to 0.11 [mm], whereas the positional deviation was 2.5 to 8. It was found that a positional shift of 5 [mm] and a position shift of about 50 to 80 times occurred.
[0028]
(Examples 10 to 12)
c. Detector body: Made of Daikin Industries, Ltd. (M-111) as modified PTFE
Lid member: as PFA, manufactured by Daikin Industries, Ltd. (AP211)
d. Insert member: stainless steel cylinder

The method of manufacturing the detector main body formed of the modified PTFE is the same as in Examples 1 to 3, and thus the description is omitted.
Next, as a method of manufacturing a lid member formed of PFA,
Mold: φ30 × L70 (column shape)
Temperature: 330-380 ° C
1 cycle: 5 minutes
After injection molding under the conditions described above, a lathe and the like were performed, and test pieces were produced under the same heat fusion conditions as in Examples 1 to 3.
The shape of the test piece was the same as that of Example 1 as described below.
Detector of flow meter according to Embodiment 2 of the present invention [unit: mm]
Test piece (10): outer diameter 4 / storage inner diameter 3 / convex peripheral wall depth 2
Test piece (11): outer diameter 10 / housing inner diameter 6 / convex peripheral wall depth 3
Test piece (12): outer diameter 20 / storage part inner diameter 15 / convex peripheral wall depth 5
[0029]
(Comparative Examples 13 to 15)
As Comparative Examples 13 to 15, detectors of a conventional welding type flowmeter were manufactured.
As a raw material, PFA (AP211 manufactured by Daikin Industries, Ltd.) was used for both the detector body and the lid member. As a manufacturing method,
Mold: φ30 × L70 (column shape)
Temperature: 330-380 ° C
1 cycle: 5 minutes
After injection molding under the conditions described above, a lathe or the like was performed, and test pieces were produced under the same welding conditions as those of Comparative Examples 4 to 6.
In addition, about the test piece shape, it was made into the same shape as a comparative example as follows.
Detector of flow meter of Comparative Example 1 [unit: mm]
Test piece (13): outer diameter 4 / storage part inner diameter 3 / groove depth 0.25
Test piece (14): outer diameter 10 / storage part inner diameter 6 / groove depth 1
Test piece (15): outer diameter 20 / storage part inner diameter 15 / groove depth 2
※ Opening angle of groove part 90 [deg]
[0030]
Next, the obtained test pieces were evaluated in the same manner as in Examples 1 to 3.
The evaluation results are shown in (Table 4) to (Table 6).
[Table 4]

[Table 5]

[Table 6]

[0031]
As is clear from Table 4, the bonding strength is about 4 to 7 times that of the conventional bonding strength, and the bonding strength is about 1.4 times per unit bonding area. You can see that.
In addition, a heat cycle test was performed to measure the sealing performance of the joint. Table 5 shows the number of defective test pieces to be compared.
As is evident from Table 5 above, the test piece of the present invention has no defect.
Next, a position measurement test was performed to measure the position deviation of the insert member. In the position measurement test, the detector is cut in a direction parallel to the axial direction, the displacement of the internal insert member from a predetermined position is measured using the probe, and the displacement value having the maximum width displacement is measured. And
Table 6 shows the displacement of the test pieces (10) to (12) and the test pieces (13) to (15) to be compared.
As is apparent from Table 6, in this embodiment, the axial displacement is 0.09 to 0.25 [mm] and the radial displacement is 0.05 to 0.08 [mm]. On the other hand, in the comparative example, it was found that the accuracy was approximately equivalent to 0.1 to 0.26 [mm] in the axial direction and 0.08 to 0.14 [mm] in the radial direction.
[0032]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a detector of a flow meter and a method of manufacturing the detector of a flow meter having the following excellent effects.
According to the detector of the flow meter according to the first aspect of the present invention, since the detector body made of the modified PTFE and the lid member made of the modified PTFE are directly heat-sealed, the bonding area can be increased. Therefore, it is possible to prevent uneven spots, easily increase the bonding strength, and obtain excellent bonding properties. In addition, since the members are directly melted and joined, the joints are integrated, and the occurrence of pin holes and the like at the joints can be prevented, thereby providing excellent reliability and durability.
According to the detector of the flow meter described in claim 2, in addition to the effects of the invention described in claim 1, when a resin composition containing PFA as a main component is used, the bonding strength can be improved.
In addition, when a resin composition containing PTFE as a main component is used, shape retention during thermal fusion can be improved, and the positioning of the insert member can be made more accurate.
[0033]
According to the detector of the flow meter according to the third aspect, in addition to the effects of the invention according to the first or second aspect, by having the convex peripheral wall portion, the detector main body made of the modified PTFE and the modified Alignment with the PTFE lid member, temporary fixing, etc. can be easily performed, and excellent workability can be obtained. In addition, since the convex peripheral wall portion is fitted into the opening, the joining area increases, and the invasion path of the external chemicals and the like becomes longer. And the joining strength can be remarkably increased, and excellent reliability, durability and joining properties can be obtained.
According to the detector of the flow meter according to the fourth aspect, in addition to the effect of the invention according to the first or second aspect, it is possible to enlarge the joining surface to enhance the joining property, and to obtain a stronger joining strength. it can.
According to the detector of the flow meter according to the fifth aspect, in addition to the effect of the invention according to the third or fourth aspect, the opening angle is provided. The formation of air holes and the like can be prevented, and excellent reliability and durability can be obtained.
[0034]
According to the manufacturing method of the detector of the flow meter according to the sixth aspect, the insert member is inserted after forming the detector body made of the modified PTFE having the storage part having the opening. The insert member can be reliably inserted into a predetermined position of the detector body made of the modified PTFE, and the insert member can be prevented from being displaced. Further, the strength is reduced due to the displaced position of the insert member, and pinholes are generated. In addition, it is possible to suppress a decrease in yield and the like, and to obtain high reliability and high productivity.
According to the detector of the flow meter according to claim 7, in addition to the effect of the invention according to claim 6, when the detector body made of modified PTFE and the lid member mainly composed of PFA are thermally fused. In addition, since the fluidity of the resin during the heat treatment is improved, the heat treatment time can be reduced, thereby improving the productivity and the energy saving. Further, when the detector is subjected to the secondary processing, the efficiency of the joining process with another component can be improved. Further, when the detector body made of modified PTFE and the lid member mainly composed of PTFE are heat-sealed, the shape retention during heat treatment is improved, so that the displacement of the inserted core material can be reduced. As a result, a highly accurate detector can be obtained.
According to the method of manufacturing the detector of the flow meter according to the eighth aspect, in addition to the effect of the invention according to the sixth or seventh aspect, the gap between the lid member and the main body of the detector is directly heated. Since the joint portion between the child body and the lid member can be easily heated, even an unskilled person can surely join and obtain excellent jointability. In addition, by setting the gap to a predetermined length, the insert member can be arranged at a predetermined position without generating a gap between the insert member and the inner wall of the storage portion, and the state of the joining surface can be improved. Can be homogenized and the quality can be improved to a level that cannot be determined from the external appearance (the level at which the joining position is difficult to determine even with a microscope observation at 200 ×).
[0035]
According to the method of manufacturing the detector of the flow meter according to the ninth aspect, in addition to the effects of the invention according to any one of the sixth to eighth aspects, the peripheral wall portion of the detector main body and the joint portion of the lid member are provided. Are securely joined from the inside toward the outside, so that the joining strength can be stably and reliably obtained, and excellent joining properties can be obtained. In addition, by having an opening angle, the exposed surface of the joint can be quickly heated, and excellent productivity can be obtained.
According to the method for manufacturing the detector of the flow meter according to the tenth aspect, in addition to the effects of the inventions according to the seventh to ninth aspects, a heat fusion process is performed on the detectors having various sizes and shapes. The versatility of jigs and tools to be used is improved, and costs can be reduced. In addition, the heat treatment time can be shortened, so that productivity can be improved and energy saving can be improved. Further, even an operator who is not familiar with the heat fusion process can understand the contents of the operation in a short time, and can improve the workability and the productivity.
According to the method of manufacturing the detector of the flow meter according to the eleventh aspect, in addition to the effect of the invention according to the tenth aspect, the detector main body and the lid member can be reliably fused to each other, and an excellent height can be obtained. Quality detectors can be obtained with high productivity.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of a detector of a flow meter according to an embodiment of the present invention.
FIG. 2 is a perspective perspective view of a detector of the flow meter according to the embodiment of the present invention.
FIG. 3 is a sectional view of a main part of a detector of the flow meter according to the embodiment of the present invention.
FIG. 4 is an enlarged view of a portion A in FIG. 3;
FIG. 5 is a cross-sectional view of a main part showing a mounting state in a mounting step of a method for manufacturing a flowmeter detector according to an embodiment of the present invention.
FIG. 6 is an exploded view of a detector of a conventional flow meter.
FIG. 7 is a perspective perspective view of a detector of a conventional flow meter.
FIG. 8 is a longitudinal sectional view of a detector of a conventional flow meter.
9 is an enlarged view of a portion B in FIG.
FIG. 10A is a perspective view of a detector of a conventional buried type flow meter.
(B) Perspective perspective view of a detector of a conventional buried type flow meter.
[Explanation of symbols]
1 Detector of flow meter
2 Detector body
3 storage
4 opening
4a Surrounding wall
5 Insert members
6 Lid member
6a convex part
6b Lid member joint
6c Convex peripheral wall
7 Heat fusion part
7a Heat-sealed part
51 Detector of conventional PTFE flow meter
52 Detector body
53 Insert member storage
54 opening
55 abutment surface
56 groove
57 Lid member
58 Contact surface
59 groove
60 convex
61 Inserts
70 Welding agent
71 Weld surface
72 Unsealed part
80 Conventional embedded detector
81 Detector body
82a, 82b Insert member

Claims

A detector main body having a storage part having an opening, an insert member inserted into the storage part, and a detector which is covered by a peripheral wall including an opening of the detector main body and is thermally fused to the detector. A lid member integrated with the main body, wherein at least one of the detector main body and the lid member is formed of modified PTFE or a resin composition containing modified PTFE as a main component. The detector of the flow meter characterized by the above.

The flowmeter according to claim 1, wherein any one of the detector main body and the lid member is formed of a resin composition containing any one of PTFE and PFA as a main component. Child.

The lid member has a ring-shaped or column-shaped projection fitted to the opening at the bottom center, a peripheral wall of the projection joined to a peripheral wall of the housing, and a periphery of the projection. A lid member joining portion to be joined to the opening peripheral wall, wherein the lid member is formed by the peripheral wall portion of the convex portion and the inner wall of the housing portion of the detector main body and the opening peripheral wall at the lid member joining portion. The detector of the flow meter according to claim 1, wherein the detector is heat-sealed and integrated.

The lid member has a lid member joining portion formed of a coaxial bulging portion protruding to the joining surface side or a concave curved surface portion depressed inward, and an opening peripheral wall of the detector main body has a bulging portion of the lid member. The lid member is formed by an inclined surface which comes into contact with a concave portion or a concave curved surface portion, and the lid member is heat-sealed at the lid member joint portion at the peripheral wall of the opening of the detector main body and integrated. 3. The detector of the flow meter according to 1 or 2.

The facing surface between the peripheral wall of the opening and the joint portion of the lid member is formed with an opening angle of 0 ° to 5 °, preferably 0.1 ° to 3 °, more preferably 0.2 ° to 3 °. The detector of the flow meter according to claim 3 or 4, wherein

A detector main body provided with a storage portion having an opening by pressing and molding powder of a modified PTFE or a resin composition containing a modified PTFE as a main component, and a lid member fitted or abutted on the opening A pressure molding step of molding a lid member having a joint, a firing step of firing the detector body and the lid member obtained in the pressure molding step, and the detector body obtained in the firing step An insertion step of inserting an insert member into the storage section, and a mounting step of mounting the lid member in the opening and / or the storage section of the detector main body into which the insert member has been inserted; The cover member mounted in the mounting step is heated while applying a stress of 0 <P <2400 [g / cm ² ], preferably 30 ≦ P ≦ 1000 [g / cm ² ] in terms of pressure. And a heat fusion step of thermally fusing each of them. A method for manufacturing a detector of a flow meter, comprising:

In the pressure molding step, the powder of any one of the detector main body and the lid member is formed of a resin composition containing any one of PTFE and PFA or one of these as a main component. The method for manufacturing a detector of a flow meter according to claim 6, wherein the detector is provided.

In the mounting step, when the lid member is fitted and mounted in the storage section of the detector main body, a gap G is provided between a lid member joint of the lid member and an opening peripheral wall of the detector main body. The gap (G) has a relation of 0 ≦ G / L ≦ 10%, preferably 0.1 ≦ G / L ≦ 5%, with respect to the total length L of the detector. 3. The method for manufacturing a detector of a flow meter according to claim 1.

The opening angle θ between the lid member joining portion and the peripheral wall of the opening is set to 0 ° <θ <5 °, preferably 0.2 ≦ θ ≦ 3 °. The method for producing a detector of a flow meter according to any one of the preceding claims.

In the heat fusion step, when the area of the fusion portion is S [cm ² ] and the total length of the flow meter is L [cm], the stress applied during thermal fusion is converted to a pressure P [g / cm ² ]. The method according to any one of claims 6 to 9, wherein the following formula is satisfied in the case of the above.
P = A (T) × (S / L) + B (T)
Here, A (T) is A (T) = − 1.13T + α, B (T) = − 0.454T + β, α = 780 to 850, β = 310 to 380, and α and β are the type and amount of resin. Is a constant determined by, T is the absolute temperature (K).

In the heat fusion step, the applied stress is 0 <P <2400 [g / cm ² ], preferably 30 ≦ P ≦ 1000 [g / cm ² ] in terms of pressure P, and the heating temperature T 11. The method according to claim 10, wherein the temperature is 250 <T <450 [° C.], preferably 320 ≦ T ≦ 390 [° C.].