JP2004045334A

JP2004045334A - Sheathed thermocouple

Info

Publication number: JP2004045334A
Application number: JP2002205977A
Authority: JP
Inventors: Yuji Tomita; 冨田　勇二
Original assignee: Yamari Industries Ltd
Current assignee: Yamari Industries Ltd
Priority date: 2002-07-15
Filing date: 2002-07-15
Publication date: 2004-02-12

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheathed thermocouple usable at a high temperature of a connection part. <P>SOLUTION: This sheathed thermocouple wherein the sheath of the sheathed thermocouple is connected to a compensating lead wire in an internal space of an external sleeve is formed as follows: the external sleeve has a cylindrical shape, an open end on the base end on the compensating lead wire side, and the other end inserted into the sheath; the other end of an internal sleeve which is a slanting open end formed by a crossing face slantingly in the axial direction of a cylindrical base end on the compensating lead wire side provided in the internal space of the external sleeve is inserted into the sheath; the end of the sheath is positioned in the internal space of the internal sleeve; two thermocouple elements exposed from the end are projected from the slanting open end; a first filling material having excellent heat-resistance and gastightness is filled in the internal space of the internal sleeve; the end of the compensating lead wire is positioned in the internal space of the external sleeve; two core wires exposed from the end are connected to the thermocouple elements; and a second filling material is filled in the internal space of the external sleeve. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、シース熱電対に関し、詳しくは補償導線を接続する接続部を有するシース熱電対に関するものである。
【０００２】
【従来の技術】
熱電対は、温度の測定が必要な装置等に広く使用されており、その測定対象によって各種のものが製作されている。これらの熱電対において、一般に、金属製の管であるシースの内部に２本の熱電対素線を通し、シース内に充填した絶縁物である酸化マグネシウム等により、シースと熱電対素線、及び、熱電対素線相互間を絶縁したものをシース熱電対と称している。このシース熱電対を用いる場合、その測温場所から、その熱電対の測定装置の所在場所まで、シースを敷設する必要がある。しかし、シース熱電対は高価であることや、シースは金属製であることから、この金属シースでの配線が機器等の短絡を引き起こす恐れのある個所等での敷設にはこの金属シースに代えて補償導線が用いられる。そのため、シース熱電対のシースと補償導線とを接続する必要があり、従来、一般に、図３に示すような接続部を有するシース熱電対が用いられている。
【０００３】
図３において、この従来例のシース熱電対における接続部２１は、シース熱電対のステンレス等の金属製のシース２２の端部と、補償導線２４の端部とが同軸上に対向して配設されて、シース熱電対と補償導線２４とが接続されている。この接続には、シース２２と同軸の筒状のスリーブで、補償導線２４側の基端２７ａが開口しており、他端はシース２２に挿着されているスリーブ２７が使用されている。そして、このスリーブ２７の内部空間内で、シース２２の端部から露出させた２本の熱電対素線２３，２３が、これらのそれぞれの接続相手である補償導線２４の端部から露出させた２本の芯線２５，２５に接続させるとともに、これらの接続部分２６，２６が、接触しないようにセパレータ２９，２９でこの接続部分２６，２６を囲んでいる。その上で、接続部分２６，２６や、熱電対素線２３，２３に応力がかかって接続部分２６，２６や、熱電対素線２３，２３等が破損するのを防ぐため、スリーブ２７の内部空間内に、充填材としてエポキシ樹脂２８が充填されて、接続部分２６，２６や、熱電対素線２３，２３がスリーブ２７の内部空間に固着されている。シース熱電対では、一般に、シースの端部の端面から、湿気等がシース内に進入して酸化マグネシウム等の電気的絶縁低下を引き起こすが、この従来例のシース熱電対の接続部２１では、シース２２の端部の端面が、スリーブ２７内に充填されたエポキシ樹脂２８内に埋設されているため、シース２２の端部の端面から湿気等がシース２２内に進入するのを防止することができる。
【０００４】
【発明が解決しようとする課題】
上記の従来例のシース熱電対における接続部２１は、上述したように、充填材としてエポキシ樹脂を用いているが、エポキシ樹脂は、２００℃程度までの環境には耐えられる。しかし、それ以上の温度になると、エポキシ樹脂が劣化することから、従来例のシース熱電対を、２００℃を超える高温で使用することが困難である。そこで、高温での使用が可能なシース熱電対における接続部２１として、充填材に、高温での使用が可能なガラスを用いることが考えられた。しかし、ガラスは、充填するためには、高温に加熱して溶融させた後、常温に戻して固着させる必要があり、これに用いるガラスと金属製のスリーブ２７の熱膨張率はできるだけ近いものを用いるにしても、全く同じとすることはかなり困難であるため、上記の従来例のシース熱電対における接続部２１において、ガラスをスリーブ２７の内部空間内に充填すると、ひび割れを起こしたり、スリーブ２７との間に隙間ができたりして、良品を製作するのが極めて困難であった。
そこで、この発明は、この問題を解決するためになされたものであって、ガラスを充填材として使用することを可能にして、補償導線を接続する接続部の高温での使用が可能なシース熱電対を提供しようとするものである。
【０００５】
【課題を解決するための手段】
本発明のシース熱電対は、その接続部の構造を工夫することによって、充填材としてガラスを使用できるようにしたものである。具体的には、本発明の第１のシース熱電対は、シース熱電対のシースと補償導線とを、外部スリーブの内部空間内で接続したシース熱電対において、外部スリーブは、筒状で補償導線側の基端に開口端を有し、他端をシースに挿着しており、外部スリーブの内部空間内に設けられた、筒状で補償導線側の基端が軸方向に斜めに横切る面で形成された傾斜開口端である内部スリーブの他端をシースに挿着し、内部スリーブの内部空間内にシースの端部を位置付けるとともに、この端部から露出させた２本の熱電対素線を傾斜開口端から突出させ、内部スリーブの内部空間内に耐熱性及び気密性に優れた第１の充填材を充填し、外部スリーブの内部空間内に補償導線の端部を位置付けるとともに、この端部から露出させた２本の芯線を熱電対素線に接続し、外部スリーブの内部空間内に第２の充填材を充填してなることを特徴としている。
【０００６】
また、本発明の第２のシース熱電対は、シース熱電対のシースと補償導線とを、外部スリーブの内部空間内で、中継線を介して接続したシース熱電対において、外部スリーブは、筒状で補償導線側の基端に開口端を有し、他端をシースに挿着しており、外部スリーブの内部空間内に設けられた、筒状で中継線側の基端が軸方向に斜めに横切る面で形成された傾斜開口端である内部スリーブの他端をシースに挿着し、内部スリーブの内部空間内にシースの端部を位置付けるとともに、この端部から露出させた２本の熱電対素線の先端に、この熱電対素線と同材質で熱電対素線よりも太い中継線を内部スリーブの内部空間内で接続して、中継線を傾斜開口端から突出させ、内部スリーブの内部空間内に耐熱性及び気密性に優れた第１の充填材を充填し、外部スリーブの内部空間内に補償導線の端部を位置付けるとともに、この端部から露出させた２本の芯線を中継線に接続し、外部スリーブの内部空間内に第２の充填材を充填してなることを特徴としている。
【０００７】
上記の第１または第２のシース熱電対において、第１の充填材として、ガラスを用いるのが好ましい。
この場合、このガラスとして、その熱膨張率が内部スリーブの熱膨張率に近いソーダバリウムガラスまたは鉛ガラスを用いるのが推奨される。
【０００８】
また、上記の第１または第２のシース熱電対において、第２の充填材として、第１の充填材よりも耐熱性に優れた充填材を用いるのが好ましい。
この場合、第２の充填材として、耐熱セメントを用いるのが推奨される。
【０００９】
また、上記の第１または第２のシース熱電対において、補償導線の芯線が、補償導線内部でその軸方向に移動するのを抑制する芯線移動抑制手段を、外部スリーブの内部空間内に位置する補償導線に設けるようにしてもよい。
【００１０】
また、上記の第１のシース熱電対において、熱電対素線の２本のそれぞれの長さを等しくするとともに、熱電対素線の第１の充填材中に埋設された部分の２本のそれぞれの長さが、ともに等しくなるように、傾斜開口端を形成するのが好ましい。
【００１１】
或は、上記の第２のシース熱電対において、熱電対素線に中継線が接続された２本のそれぞれの合計の長さを等しくするとともに、熱電対素線に中継線が接続されたものの、第１の充填材中に埋設された部分の２本のそれぞれの長さが、ともに等しくなるように、傾斜開口端を形成するのが好ましい。
【００１２】
【発明の実施の形態】
次に、本発明の実施例につき、図面に基づき詳しく説明する。図１（ａ）は、本発明の第１実施例のシース熱電対における接続部の垂直断面図であり、（ｂ）は、水平断面図である。図１（ａ）、（ｂ）において、本発明の第１実施例のシース熱電対における接続部１は、シース熱電対のシース２の端部と補償導線６の端部とを同軸上に対向して配設してシース熱電対と補償導線とを接続する。シース熱電対のシース２は一般に金属製で、本第１実施例のシース熱電対ではステンレス製である。シース熱電対と補償導線との接続には、外部スリーブ１０と内部スリーブ８とを使用する。
外部スリーブ１０はステンレス製で、シース熱電対のシース２と同軸で、内部に空間を有する円筒であり、補償導線６側の基端が開口しているとともに、他端は基端から遠ざかるにつれてラッパ状にすぼませて、シース２に挿着して、このシース２に固定している。
内部スリーブ８は、外部スリーブ１０の内部空間内に設けられ、ステンレス製または鉄−ニッケル合金製で、シース２と同軸で、内部に空間を有する円筒であり、補償導線６側の基端が開口しており、他端をシース２の端部に挿着して、このシース２に固定している。この内部スリーブ８の基端には、この内部スリーブ８をその軸を軸方向に斜めに横切る斜面で構成される傾斜開口端８ａを有している。即ち、この内部スリーブ８は中空のパイプを斜めに切断した形状をしている。
【００１３】
この内部スリーブ８の内部空間内において、シース熱電対のシース２の端部から露出させた２本の同じ長さの熱電対素線３を、内部スリーブ８の軸にほぼ平行に相互に絶縁間隔を十分保った状態で、内部スリーブ８の傾斜開口端８ａから突出させる。そして、この内部スリーブ８の内部空間内に、耐熱性、及び、気密性、即ち、耐吸湿性に優れた第１の充填材９を充填する。この第１の充填材９としては、ソーダバリウムガラス（以下ガラスと称する）を用いる。このガラスは、その軟化点が７００℃前後であり、５００℃以上の耐熱性を有しているとともに耐吸湿性に優れている。この充填は内部スリーブ８の傾斜開口端８ａから、シース２の端部に挿着している他端へ向かって、溶融したガラスを注入して行われ、内部スリーブ８の傾斜開口端８ａをガラス９で閉塞する。即ち、ガラス９で充填後の、内部スリーブ８の形状は、中空のパイプの中空内にガラスを充填したパイプを、斜めに切断したのと同じ形状である。このように内部スリーブ８の形状を、単なる円筒形とせずに、中空のパイプを斜めに切断したような形状とするのは、次のような理由による。即ち、単なる円筒形とすると、その中に溶融したガラス９を充填した際に、ステンレス製または鉄−ニッケル合金製の内部スリーブ８と充填されたガラス９の熱膨張率の違いにより、そのガラス９が凝固する際に、内部スリーブ８との間に隙間が出来たり、ガラス９にひびが入ったりし易い。しかし、中空のパイプを斜めに切断したような形状とすることにより、このような隙間やひび割れの発生を避けることが出来る。
【００１４】
上記の形状の内部スリーブ８を用いることにより、内部スリーブ８に充填したガラス９のひび割れ等を防止することができるが、このガラス９のひび割れ等の防止の観点からは、内部スリーブ８の材質の熱膨張率と、この内部スリーブ８に充填するガラスの熱膨張率とができるだけ近似していることが望ましい。例えば、ガラスとして、本実施例のようにソーダバリウムガラスを用いる場合、その熱膨張率は９０〜１１０×１０^−７／℃であり、内部スリーブ８の材質としてステンレスや鉄−ニッケル合金を用いる場合、それらの熱膨張率が９０〜１１０×１０^−７／℃のものが存在する。これらの中の最適なものを組み合わせることにより、内部スリーブ８に充填したガラス９のひび割れ等の防止を効果的に行うことができる。
【００１５】
内部スリーブ８へのガラス９の充填の結果、ガラス９中に、シース２の端部とその端面２ａ、及び、熱電対素線３の一部が、絶縁間隔を十分保った状態で埋設される。また、前述したように、シース熱電対のシース２内には、シース２と熱電対素線３間、及び、熱電対素線３相互間を絶縁するため、酸化マグネシウム等の絶縁物が充填されているが、このシース２の端面を空気中にさらすと、このシース２の端面から湿気が侵入して、酸化マグネシウムの電気的絶縁を低下させる恐れがある。しかし、上述したように、本第１実施例ではシース２の端部の端面２ａが耐吸湿性に優れたガラス９中に埋設されるので、シース２の端部の端面２ａからの吸湿を防止することができる。また、この充填により、傾斜開口端８ａから、内部スリーブ８の軸に平行に２本の熱電対素線３が突出した状態となる。この際、この２本の熱電対素線３の各突出位置からシース２の端部までの距離、即ち、２本の熱電対素線３がガラス９中に埋設される部分の長さが、ともに等しくなるように、傾斜開口端８ａを形成する。そして、補償導線６の端部から露出させた２本の芯線５を、外部スリーブ１０の内部空間内でこれらのそれぞれの接続相手である、内部スリーブ８の傾斜開口端８ａから突出させた上記２本の熱電対素線３に、溶接して接続する。ここで、２本の熱電対素線３がガラス９中に埋設される部分の長さをともに等しくなるようにするのは、もともと、２本の熱電対素線３の長さが同じであることから、このようにすることにより、傾斜開口端８ａから突出する２本の熱電対素線３を同じ長さにそろえることができ、下記に述べる外部スリーブ１０の内部空間内に第２の充填材１１を充填する際に、突出する２本の熱電対素線３に対する、絶縁間隔の保持や折れ曲がり等に対する強度を同じとすることができるからであり、これにより、品質レベルを一定に保つことができる。
【００１６】
また、補償導線６の端部付近を、この補償導線６の中の芯線５が軸方向に移動しないように、補償導線外周部からその軸中心に向かって金属製のバンドである芯線移動抑制金具７を用いて強く締め付ける。これは、補償導線６を敷設の際、補償導線６を曲げたりした際に、その芯線５が補償導線６内部でその軸方向に移動することにより、熱電対素線３と芯線５との接続部分４に、圧縮応力や引っ張り応力がかかって、この接続部分４が破損したり変形したりするのを防ぐためである。この芯線移動抑制金具７や補償導線６の端部、補償導線６の芯線５、熱電対素線３の一部、補償導線６の芯線５と熱電対素線３との接続部分４、及び、内部スリーブ８は、外部スリーブ１０の内部空間内に納まるように配設される。この状態で、外部スリーブ１０の内部空間内に第２の充填材１１を充填して、内部スリーブ８とともに、芯線移動抑制金具７、補償導線６の端部、補償導線６の芯線５、熱電対素線３の一部、及び、補償導線６の芯線５と熱電対素線３との接続部分４を、外部スリーブ１０の内部空間内に固着する。従って、外部スリーブ１０内で、内部スリーブ８、芯線移動抑制金具７、補償導線６の端部、補償導線６の芯線５、熱電対素線３の一部、及び、補償導線６の芯線５と熱電対素線３との接続部分４が動くことはないので、外部スリーブ１０内の、補償導線６の芯線５、熱電対素線３の一部、及び、補償導線６の芯線５と熱電対素線３との接続部分４に、曲げ応力、圧縮応力や引っ張り応力がかかるのを防ぐことができ、機械的な耐衝撃性に優れた接続部とすることができる。また、充填用の第２の充填材１１としては、内部スリーブ８保護の観点から、対吸湿性は多少劣っても内部スリーブ８に充填する第１の充填材９よりも、耐熱性に優れたものが好ましい。外部スリーブ１０の充填材１１が内部スリーブ８に充填する第１の充填材９よりも、耐熱性に優れたものを用いることによって、内部スリーブ８に対する熱的な耐衝撃性を向上させることができ、内部スリーブ８に充填する第１の充填材９の耐熱温度まで、確実に使用できることを保証することができ、熱的な耐衝撃性に優れた接続部とすることができる。ここでは、この第２の充填材として、耐熱セメントを用いている。
【００１７】
第１実施例のシース熱電対によれば、その接続部１において、軸方向に斜めに横切る斜面で構成される傾斜開口端８ａを有する内部スリーブ８を用いることにより、この内部スリーブ８に耐熱性、耐吸湿性に優れたガラス９を充填することが可能となり、シース２の端部の端面２ａを耐吸湿性に優れたガラス９中に埋設させることで、シース２の端部の端面２ａからの吸湿を防止することができるので、高温での使用が可能な接続部を備えたシース熱電対を提供することができる。
【００１８】
上記の第１実施例のシース熱電対では、その接続部１において、補償導線６の端部から露出させた２本の芯線５を、外部スリーブ１０の内部空間内でこれらのそれぞれの接続相手である、内部スリーブ８の傾斜開口端８ａから突出させた上記２本の熱電対素線３に、直接溶接して接続している。熱電対素線３が比較的太い場合は、この方法で問題は生じないが、熱電対素線３の直径が、例えば、０．０５ｍｍのような細い熱電対素線の場合、次のような問題を生じる。即ち、熱電対素線３を、内部スリーブ８の傾斜開口端８ａから突出させて、この内部スリーブ８の内部空間内に、融点が７００℃前後の溶融したガラス９を充填すると、このガラス９の熱で熱電対素線３が酸化してもろくなる可能性が大きく、熱電対素線３を補償導線６の芯線５に溶接して接続する際や、外部スリーブ１０の内部空間内に第２の充填材１１を充填する際に、切断しやすくなる。そこで、次に、この問題に対する解決を図った第２実施例のシース熱電対について説明する。
【００１９】
図２（ａ）は、第２実施例のシース熱電対における接続部の垂直断面図であり、（ｂ）は、水平断面図である。第２実施例のシース熱電対における接続部は、第１実施例のシース熱電対とほとんど同じであり、図２（ａ）、（ｂ）において、第１実施例と同じ部分は、図１（ａ）、（ｂ）の第１実施例と同じ番号を用いている。第１実施例と異なるのは、補償導線６の芯線５を、内部スリーブ８の傾斜開口端８ａから突出させた熱電対素線３に、直接接続するのではなく、補償導線６の芯線５と熱電対素線３との間に、これらを中継する熱電対素線３と同材質で、熱電対素線３よりも太い中継線１５を用いていることである。
【００２０】
即ち、図２（ａ）、（ｂ）において、内部スリーブ８の内部空間内において、シース熱電対のシース２の端部から露出させた２本の熱電対素線３の先端に、熱電対素線３と同材質で、熱電対素線３よりも太く、かつ、内部スリーブ８の傾斜開口端８ａから突出させることができる長さの２本の中継線１５を、それぞれ溶接して接続する。そして、２本の熱電対素線３、中継線１５、及び、熱電対素線３と中継線１５との接続部分１６の各絶縁間隔を十分保った状態で、この内部スリーブ８の内部空間内に、耐熱性、及び、耐吸湿性に優れたガラス９を第１実施例と同様にして充填する。その結果、ガラス９中に、シース２の端部とその端面２ａ、熱電対素線３、中継線１５の一部、及び、熱電対素線３と中継線１５との接続部分１６が、絶縁間隔を十分保った状態で埋設される。この充填の際、中継線１５は熱電対素線３と同材質で、熱電対素線３よりも太いので、熱電対素線３と比べて中継線１５はガラス９が溶融する際の熱により酸化しても、もろくなりにくく、中継線１５を補償導線６の芯線５に溶接して接続する際や、外部スリーブ１０の内部空間内に耐熱セメントを充填する際の切断事故を防止することができる。
【００２１】
この第２実施例では、２本の熱電対素線３の先端に中継線１５を接続した２本のそれぞれの全体の長さを同一とするとともに、この２本の熱電対素線３の先端に中継線１５を接続したものの、第１の充填材９中に埋設される部分のそれぞれの長さが、ともに等しくなるように、傾斜開口端８ａを形成する。こうすることにより、２本の中継線１５が傾斜開口端８ａから突出する部分の長さを同じとすることができ、そのため、外部スリーブ１０の内部空間内に第２の充填材１１を充填する際に、傾斜開口端８ａから突出する２本の中継線１５に対する、絶縁間隔の保持や折れ曲がり等に対する強度を同じとすることができ、品質レベルを一定に保つことができる。
【００２２】
また、この第２実施例では、第１実施例と同様に、芯線移動抑制金具７を設ける。また、補償導線６の端部から露出させた２本の芯線５を、これらのそれぞれの接続相手である、内部スリーブ８の傾斜開口端８ａから突出させた２本の中継線１５に、外部スリーブ１０の内部空間内で接続するとともに、外部スリーブ１０の内部空間内に第２の充填材１１を充填して、内部スリーブ８とともに、芯線移動抑制金具７、補償導線６の端部、補償導線６の芯線５、中継線１５と補償導線６の芯線５との接続部分１７、及び、内部スリーブ８の傾斜開口端８ａから突出している中継線１５を、外部スリーブ１０の内部空間内に固着する。この第２の充填材１１として、第１実施例と同様に、耐熱セメントを用いている。
【００２３】
上記の構造から明らかなように、第２実施例のシース熱電対においても、上述した中継線１５の作用効果のほか、第１実施例のシース熱電対と同様の作用効果を有する。
【００２４】
上記の第１実施例または第２実施例のシース熱電対では、第１の充填材として、ソーダバリウムガラスを用いているが、鉛ガラスやその他のガラスを用いるようにしてもよい。この場合、これらのガラスの熱膨張率が内部スリーブの材質の熱膨張率に近いものが望ましい。また、第１の充填材としては、ガラスには限られず、耐熱性と気密性に優れているものであれば、いかなる充填材を使用してもよい。また、第２の充填材として、耐熱セメントを用いているが、外部スリーブの内部空間内における埋設物の固着が可能で耐熱性を備えた充填材であれば、いかなるものでもよい。
【００２５】
【発明の効果】
請求項１記載の発明によれば、シース熱電対のシースと補償導線とを接続するのに、軸方向に斜めに横切る斜面で構成される傾斜開口端を有する内部スリーブを用いることにより、この内部スリーブに耐熱性及び気密性に優れた第１の充填材を充填することが可能となり、シースの端部の端面を耐熱性及び気密性に優れた第１の充填材中に埋設させることで、シースの端部の端面からの吸湿を防止することができるので、高温での使用が可能なシース熱電対を提供することができる。
【００２６】
請求項２記載の発明によれば、請求項１記載の発明の効果のほか、次の効果を有する。シース熱電対のシースと補償導線との接続において、熱電対素線にこの熱電対素線と同材質で熱電対素線よりも太い中継線を接続して用いるので、溶融した高温の充填材を内部スリーブの内部空間内に充填する際も、中継線は熱電対素線と比べて充填材溶融の際の熱により酸化しても、もろくなりにくく、中継線を補償導線の芯線に接続する際や、外部スリーブの内部空間内に耐熱セメントを充填する際の切断事故を防止することができるシース熱電対を提供することができる。
【００２７】
請求項３または４記載の発明によれば、シース熱電対のシースと補償導線との接続において、内部スリーブの充填する第１の充填材として耐熱性及び気密性に優れたガラスを用いるので高温での使用が可能なシース熱電対を提供することができる。
【００２８】
請求項５または６記載の発明によれば、シース熱電対のシースと補償導線との接続において、外部スリーブの内部空間内に充填するのに用いる第２の充填材を内部スリーブに充填する第１の充填材よりも、耐熱性に優れた充填材を用いるので、内部スリーブに充填する第１の充填材の耐熱温度まで、確実に使用できることを保証することができるとともに、熱的及び機械的な耐衝撃性に優れたシース熱電対を提供することができる。
【００２９】
請求項７記載の発明によれば、シース熱電対のシースと補償導線との接続において、補償導線の芯線が、補償導線内部でその軸方向に移動するのを抑制する芯線移動抑制手段を、外部スリーブの内部空間内に位置する補償導線に設けているので、補償導線を敷設の際、補償導線を曲げたりした際に、その芯線が補償導線内部でその軸方向に移動することにより、熱電対素線と芯線との接続部分に、圧縮応力や引っ張り応力がかかって、この接続部分が破損したり変形したりするのを防ぐことができるシース熱電対を提供することができる。
【００３０】
請求項８または９記載の発明によれば、シース熱電対のシースと補償導線との接続において、２本の熱電対素線、または２本の中継線が傾斜開口端から突出する部分の長さを同じとすることができ、そのため、外部スリーブの内部空間内に第２の充填材を充填する際に、傾斜開口端から突出する２本の熱電対素線、または２本の中継線に対する、絶縁間隔の保持や折れ曲がり等に対する強度を同じとすることができ、品質レベルを一定に保つことができるシース熱電対を提供することができる。
【図面の簡単な説明】
【図１】（ａ）は、第１実施例のシース熱電対における接続部の垂直断面図であり、（ｂ）は、水平断面図である。
【図２】（ａ）は、第２実施例のシース熱電対における接続部の垂直断面図であり、（ｂ）は、水平断面図である。
【図３】従来例のシース熱電対における接続部の断面図である。
【符号の説明】
１　　シース熱電対の接続部
２　　シース
２ａ　　シースの端部の端面
３　　熱電対素線
４　　熱電対素線と芯線との接続部分
５　　補償導線の芯線
６　　補償導線
７　　芯線移動抑制金具
８　　内部スリーブ
８ａ　　内部スリーブの傾斜開口端
９　　第１の充填材（ソーダバリウムガラス）
１０　　外部スリーブ
１１　　第２の充填材（耐熱セメント）
１５　　中継線
１６　　熱電対素線と中継線との接続部分
１７　　中継線と補償導線の芯線との接続部分
２１　　シース熱電対の接続部
２２　　シース
２３　　熱電対素線
２４　　補償導線
２５　　芯線
２６　　接続部分
２７　　スリーブ
２７ａ　　スリーブの基端
２８　　エポキシ樹脂
２９　　絶縁用セパレータ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheath thermocouple, and more particularly, to a sheath thermocouple having a connecting portion for connecting a compensating lead wire.
[0002]
[Prior art]
Thermocouples are widely used in devices and the like that require temperature measurement, and various types of thermocouples are manufactured depending on the measurement target. In these thermocouples, generally, two thermocouple wires are passed through a sheath that is a metal tube, and the sheath and the thermocouple wire are separated by magnesium oxide or the like that is an insulator filled in the sheath. Insulation between thermocouple wires is called a sheath thermocouple. When this sheath thermocouple is used, it is necessary to lay a sheath from the temperature measuring location to the location of the measuring device of the thermocouple. However, since the sheath thermocouple is expensive and the sheath is made of metal, it should be replaced with this metal sheath when laying at places where wiring with this metal sheath may cause short-circuiting of equipment etc. A compensating lead is used. Therefore, it is necessary to connect the sheath of the sheath thermocouple and the compensating conductor, and a sheath thermocouple having a connection portion as shown in FIG. 3 is generally used.
[0003]
In FIG. 3, a connecting portion 21 of the conventional sheath thermocouple is disposed such that an end of a sheath 22 made of a metal such as stainless steel of the sheath thermocouple and an end of a compensating wire 24 are coaxially opposed to each other. Then, the sheath thermocouple and the compensating conductor 24 are connected. For this connection, a cylindrical sleeve coaxial with the sheath 22 is used, the base end 27a of the compensating lead wire 24 is open, and the other end is used with the sleeve 27 inserted into the sheath 22. Then, in the internal space of the sleeve 27, the two thermocouple wires 23, 23 exposed from the ends of the sheath 22 are exposed from the ends of the compensating lead wires 24, which are their respective connection partners. The connecting portions 26, 26 are connected to the two core wires 25, 25, and the connecting portions 26, 26 are surrounded by separators 29, 29 so that they do not come into contact with each other. In addition, in order to prevent the connection portions 26, 26 and the thermocouple wires 23, 23 from being stressed to damage the connection portions 26, 26, the thermocouple wires 23, 23, etc. The space is filled with an epoxy resin 28 as a filler, and the connection portions 26, 26 and the thermocouple wires 23, 23 are fixed to the inner space of the sleeve 27. In the sheath thermocouple, generally, moisture or the like enters the sheath from the end face of the end of the sheath and causes a decrease in electrical insulation such as magnesium oxide. Since the end face of the end of the sheath 22 is embedded in the epoxy resin 28 filled in the sleeve 27, it is possible to prevent moisture and the like from entering the sheath 22 from the end face of the end of the sheath 22. .
[0004]
[Problems to be solved by the invention]
As described above, the connection portion 21 of the conventional sheath thermocouple uses the epoxy resin as the filler, but the epoxy resin can withstand an environment up to about 200 ° C. However, if the temperature is higher than that, the epoxy resin is deteriorated, so that it is difficult to use the conventional sheath thermocouple at a high temperature exceeding 200 ° C. Therefore, it has been considered to use glass that can be used at a high temperature as the filler as the connecting portion 21 in the sheath thermocouple that can be used at a high temperature. However, in order to fill the glass, it is necessary to melt the material by heating it to a high temperature and then return it to normal temperature and fix it. The glass used for this purpose and the metal sleeve 27 should have a coefficient of thermal expansion as close as possible. Even if they are used, it is quite difficult to make them exactly the same. Therefore, when glass is filled in the inner space of the sleeve 27 at the connecting portion 21 in the above-mentioned conventional sheath thermocouple, cracks occur or the sleeve 27 It was extremely difficult to produce a good product due to the formation of a gap between them.
Therefore, the present invention has been made to solve this problem, and it has been made possible to use glass as a filler, and to use a sheath thermoelectric device which can use a connecting portion for connecting a compensating wire at a high temperature. It is intended to provide a pair.
[0005]
[Means for Solving the Problems]
The sheath thermocouple of the present invention is such that glass can be used as a filler by devising the structure of the connection portion. Specifically, the first sheath thermocouple of the present invention is a sheath thermocouple in which the sheath of the sheath thermocouple and the compensating conductor are connected in the inner space of the outer sleeve. Surface having an open end at the base end on the side, the other end being inserted into the sheath, and a cylindrical, base end on the compensating wire side obliquely crossing in the axial direction provided in the internal space of the outer sleeve. The other end of the inner sleeve, which is the inclined open end formed by the above, is inserted into the sheath, the end of the sheath is positioned in the inner space of the inner sleeve, and the two thermocouple wires exposed from this end are provided. Is projected from the inclined open end, the inner space of the inner sleeve is filled with a first filler excellent in heat resistance and airtightness, and the end of the compensating wire is positioned in the inner space of the outer sleeve. Two core wires exposed from the part are thermocouple wires Connect, is characterized by formed by filling the second sealing member within the interior space of the outer sleeve.
[0006]
The second sheath thermocouple of the present invention is a sheath thermocouple in which the sheath of the sheath thermocouple and the compensating conductor are connected via a relay wire in the inner space of the outer sleeve. Has an open end at the base end on the compensating lead side, the other end is inserted into the sheath, and the cylindrical base end on the relay wire side provided in the internal space of the outer sleeve is oblique in the axial direction. The other end of the inner sleeve, which is an inclined open end formed by a plane crossing the inner sleeve, is inserted into the sheath, the end of the sheath is positioned in the inner space of the inner sleeve, and the two thermoelectrics exposed from this end are inserted. At the end of the pair of wires, a relay wire made of the same material as the thermocouple wire and having a larger thickness than the thermocouple wire is connected in the internal space of the inner sleeve. Fill the interior space with the first filler with excellent heat resistance and airtightness. Then, the end of the compensating lead wire is positioned in the inner space of the outer sleeve, and the two core wires exposed from the ends are connected to the relay wire to fill the inner space of the outer sleeve with the second filler. It is characterized by becoming.
[0007]
In the above-described first or second sheath thermocouple, it is preferable to use glass as the first filler.
In this case, it is recommended to use soda barium glass or lead glass whose glass has a coefficient of thermal expansion close to that of the inner sleeve.
[0008]
In the first or second sheath thermocouple, it is preferable to use, as the second filler, a filler having higher heat resistance than the first filler.
In this case, it is recommended to use heat-resistant cement as the second filler.
[0009]
In the above-mentioned first or second sheath thermocouple, the core wire movement suppressing means for preventing the core wire of the compensating wire from moving in the axial direction inside the compensating wire is located in the internal space of the outer sleeve. You may make it provide in a compensating lead.
[0010]
In the first sheath thermocouple, each of the two thermocouple wires has the same length, and each of the two portions of the thermocouple wire embedded in the first filler. It is preferable to form the inclined open ends so that the lengths are equal.
[0011]
Alternatively, in the above-described second sheath thermocouple, the total length of each of the two thermocouple wires to which the relay wire is connected is equal, and the relay wire is connected to the thermocouple wire. It is preferable to form the inclined open end so that the lengths of the two portions buried in the first filler are equal to each other.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1A is a vertical sectional view of a connecting portion in a sheath thermocouple according to a first embodiment of the present invention, and FIG. 1B is a horizontal sectional view. 1 (a) and 1 (b), a connecting portion 1 in a sheath thermocouple according to a first embodiment of the present invention is coaxially opposed to an end of a sheath 2 of the sheath thermocouple and an end of a compensating lead wire 6. And connect the sheath thermocouple and the compensating lead. The sheath 2 of the sheath thermocouple is generally made of metal, and the sheath thermocouple of the first embodiment is made of stainless steel. An outer sleeve 10 and an inner sleeve 8 are used to connect the sheath thermocouple and the compensating lead.
The outer sleeve 10 is made of stainless steel, is coaxial with the sheath 2 of the sheath thermocouple, is a cylinder having a space inside, and has an opening at the base end of the compensating conductor 6 side, and the other end has a wrapper as the distance from the base end increases. It is inserted into the sheath 2 and fixed to the sheath 2.
The inner sleeve 8 is provided in the inner space of the outer sleeve 10, is made of stainless steel or an iron-nickel alloy, is a cylinder coaxial with the sheath 2, and has a space inside, and the base end of the compensating lead 6 is open. The other end is inserted into the end of the sheath 2 and fixed to the sheath 2. The base end of the inner sleeve 8 has an inclined open end 8a formed by a slope that obliquely crosses the axis of the inner sleeve 8 in the axial direction. That is, the inner sleeve 8 has a shape obtained by cutting a hollow pipe obliquely.
[0013]
In the internal space of the inner sleeve 8, two thermocouple wires 3 of the same length exposed from the end of the sheath 2 of the sheath thermocouple are insulated from each other substantially in parallel to the axis of the inner sleeve 8. Is held from the inclined open end 8a of the inner sleeve 8 in a state where is sufficiently maintained. Then, a first filler 9 having excellent heat resistance and airtightness, that is, excellent moisture absorption resistance, is filled in the internal space of the internal sleeve 8. As the first filler 9, soda barium glass (hereinafter, referred to as glass) is used. This glass has a softening point of about 700 ° C., has a heat resistance of 500 ° C. or more, and is excellent in moisture absorption resistance. This filling is performed by injecting molten glass from the inclined open end 8a of the inner sleeve 8 toward the other end inserted into the end of the sheath 2, and the inclined open end 8a of the inner sleeve 8 is filled with glass. Close at 9. That is, the shape of the inner sleeve 8 after being filled with the glass 9 is the same as the shape obtained by diagonally cutting a pipe filled with glass in the hollow of a hollow pipe. The reason why the shape of the inner sleeve 8 is not a simple cylindrical shape but a shape obtained by cutting a hollow pipe obliquely is as follows. That is, if the glass 9 is simply cylindrical, when the glass 9 is filled with the molten glass 9, the difference in the coefficient of thermal expansion between the inner sleeve 8 made of stainless steel or an iron-nickel alloy and the filled glass 9 causes the glass 9 to melt. When solidified, a gap is easily formed between the inner sleeve 8 and the glass 9, and the glass 9 is easily cracked. However, by forming the hollow pipe into a shape obliquely cut, the occurrence of such gaps and cracks can be avoided.
[0014]
By using the inner sleeve 8 having the above-described shape, it is possible to prevent the glass 9 filled in the inner sleeve 8 from being cracked. However, from the viewpoint of preventing the glass 9 from being cracked, the material of the inner sleeve 8 may be reduced. It is desirable that the coefficient of thermal expansion and the coefficient of thermal expansion of the glass filling the inner sleeve 8 be as close as possible. For example, when soda barium glass is used as the glass as in this embodiment, the coefficient of thermal expansion is 90 to 110 × 10 ^-7 / ° C., and when stainless steel or an iron-nickel alloy is used as the material of the inner sleeve 8, their coefficient of thermal expansion is 90 to 110 × 10 ^-7 / ° C. By combining the optimum ones of these, it is possible to effectively prevent the glass 9 filled in the inner sleeve 8 from cracking.
[0015]
As a result of filling the inner sleeve 8 with the glass 9, the end of the sheath 2, the end face 2 a thereof, and a part of the thermocouple wire 3 are buried in the glass 9 while keeping a sufficient insulation interval. . Further, as described above, the sheath 2 of the sheath thermocouple is filled with an insulator such as magnesium oxide to insulate the sheath 2 from the thermocouple wires 3 and the thermocouple wires 3 from each other. However, if the end face of the sheath 2 is exposed to the air, moisture may enter from the end face of the sheath 2 and the electrical insulation of magnesium oxide may be reduced. However, as described above, in the first embodiment, since the end face 2a of the end of the sheath 2 is embedded in the glass 9 having excellent moisture absorption resistance, moisture absorption from the end face 2a of the end of the sheath 2 is prevented. can do. By this filling, two thermocouple wires 3 project from the inclined opening end 8a in parallel with the axis of the inner sleeve 8. At this time, the distance from each projecting position of the two thermocouple wires 3 to the end of the sheath 2, that is, the length of the portion where the two thermocouple wires 3 are embedded in the glass 9 is: An inclined opening end 8a is formed so as to be equal to each other. Then, the two core wires 5 exposed from the ends of the compensating lead wire 6 project from the inclined open end 8a of the inner sleeve 8, which is their respective connection partner, in the inner space of the outer sleeve 10. The two thermocouple wires 3 are connected by welding. Here, the reason why the two thermocouple wires 3 are made to have the same length in a portion embedded in the glass 9 is that the lengths of the two thermocouple wires 3 are originally the same. Therefore, by doing so, the two thermocouple wires 3 protruding from the inclined opening end 8a can be made equal in length, and the second filling in the inner space of the outer sleeve 10 described below can be performed. This is because, when the material 11 is filled, the two thermocouple wires 3 projecting from each other can have the same strength with respect to the maintenance of the insulation interval and the bending, etc., so that the quality level can be kept constant. Can be.
[0016]
In addition, a core wire movement suppressing metal fitting, which is a metal band from the outer peripheral portion of the compensating conductor toward the center of the axis, so that the core 5 in the compensating conductor 6 does not move in the axial direction near the end of the compensating conductor 6. Use 7 to tighten strongly. This is because, when the compensating conductor 6 is laid or the compensating conductor 6 is bent, the core wire 5 moves in the axial direction inside the compensating conductor 6, thereby connecting the thermocouple element wire 3 to the core wire 5. This is to prevent the connection portion 4 from being damaged or deformed due to a compressive stress or a tensile stress applied to the portion 4. End portions of the core wire movement suppressing metal fitting 7 and the compensating conductor 6, the core wire 5 of the compensating wire 6, a part of the thermocouple wire 3, a connecting portion 4 between the core wire 5 of the compensating wire 6 and the thermocouple wire 3, and The inner sleeve 8 is provided so as to fit in the inner space of the outer sleeve 10. In this state, the inner space of the outer sleeve 10 is filled with the second filler 11, and together with the inner sleeve 8, the core wire movement suppressing metal fitting 7, the end of the compensating lead wire 6, the core wire 5 of the compensating lead wire 6, and the thermocouple A part of the wire 3 and a connecting portion 4 between the core wire 5 of the compensating lead wire 6 and the thermocouple wire 3 are fixed in the internal space of the outer sleeve 10. Therefore, in the outer sleeve 10, the inner sleeve 8, the core wire movement suppressing fitting 7, the end of the compensating wire 6, the core wire 5 of the compensating wire 6, a part of the thermocouple wire 3, and the core wire 5 of the compensating wire 6 Since the connection portion 4 with the thermocouple wire 3 does not move, the core wire 5 of the compensating wire 6, a part of the thermocouple wire 3, and the core wire 5 of the compensating wire 6 and the thermocouple in the outer sleeve 10. It is possible to prevent a bending stress, a compressive stress and a tensile stress from being applied to the connection portion 4 with the strand 3, and it is possible to provide a connection portion excellent in mechanical shock resistance. In addition, from the viewpoint of protection of the inner sleeve 8, the second filler 11 for filling is more excellent in heat resistance than the first filler 9 filling the inner sleeve 8, though the moisture absorption is somewhat inferior. Are preferred. By using a material having better heat resistance than the first filler 9 in which the filler 11 of the outer sleeve 10 fills the inner sleeve 8, thermal shock resistance to the inner sleeve 8 can be improved. In addition, it can be ensured that the first filling material 9 to be filled in the inner sleeve 8 can be used reliably up to the heat resistant temperature, and a connection portion having excellent thermal shock resistance can be obtained. Here, heat-resistant cement is used as the second filler.
[0017]
According to the sheath thermocouple of the first embodiment, by using the inner sleeve 8 having the inclined open end 8a constituted by the inclined surface obliquely crossing in the axial direction at the connection portion 1, the inner sleeve 8 has heat resistance. In addition, it becomes possible to fill the glass 9 having excellent moisture absorption resistance, and by embedding the end face 2a of the end of the sheath 2 in the glass 9 having excellent moisture absorption, the end face 2a of the end of the sheath 2 can be filled. Therefore, it is possible to provide a sheath thermocouple having a connecting portion that can be used at a high temperature.
[0018]
In the sheath thermocouple of the above-described first embodiment, the two core wires 5 exposed from the end of the compensating lead wire 6 are connected to the respective connecting partners in the internal space of the outer sleeve 10 at the connection portion 1. The two thermocouple wires 3 projecting from the inclined open end 8a of the inner sleeve 8 are directly welded and connected. When the thermocouple wire 3 is relatively thick, this method does not cause any problem. However, when the thermocouple wire 3 is a thin thermocouple wire having a diameter of, for example, 0.05 mm, the following method is used. Cause problems. That is, when the thermocouple wire 3 is made to protrude from the inclined opening end 8a of the inner sleeve 8 and the inner space of the inner sleeve 8 is filled with the molten glass 9 having a melting point of about 700 ° C., There is a great possibility that the thermocouple wire 3 will become fragile if oxidized by heat, and when the thermocouple wire 3 is connected to the core wire 5 of the compensating lead wire 6 by welding, or in the internal space of the outer sleeve 10, When filling with the filler material 11, it becomes easier to cut. Therefore, a sheath thermocouple according to a second embodiment for solving this problem will now be described.
[0019]
FIG. 2A is a vertical sectional view of a connecting portion in the sheath thermocouple of the second embodiment, and FIG. 2B is a horizontal sectional view. The connection part in the sheath thermocouple of the second embodiment is almost the same as that of the sheath thermocouple of the first embodiment. In FIGS. 2A and 2B, the same parts as those of the first embodiment are the same as those of FIG. The same numbers as in the first embodiment of FIGS. The difference from the first embodiment is that the core wire 5 of the compensating lead 6 is not directly connected to the thermocouple wire 3 protruding from the inclined open end 8a of the inner sleeve 8, but is connected to the core 5 of the compensating lead 6. A difference between the thermocouple wire 3 and the thermocouple wire 3 is that a relay wire 15 made of the same material as the thermocouple wire 3 and having a larger thickness than the thermocouple wire 3 is used.
[0020]
That is, in FIGS. 2A and 2B, in the internal space of the inner sleeve 8, a thermocouple element is attached to the ends of the two thermocouple wires 3 exposed from the ends of the sheath 2 of the sheath thermocouple. Two relay wires 15 made of the same material as the wire 3 and having a thickness larger than that of the thermocouple wire 3 and a length protruding from the inclined opening end 8a of the inner sleeve 8 are connected by welding. Then, with the two thermocouple wires 3, the relay wire 15, and the connection portion 16 between the thermocouple wire 3 and the relay wire 15 being sufficiently spaced apart from each other, the inside space of the inner sleeve 8 is maintained. Then, glass 9 excellent in heat resistance and moisture absorption resistance is filled in the same manner as in the first embodiment. As a result, in the glass 9, the end of the sheath 2 and its end face 2 a, the thermocouple wire 3, a part of the relay wire 15, and the connection portion 16 between the thermocouple wire 3 and the relay wire 15 are insulated. It is buried with sufficient space. At the time of this filling, the relay wire 15 is made of the same material as the thermocouple wire 3 and is thicker than the thermocouple wire 3. Even if it is oxidized, it does not easily become brittle, and it is possible to prevent a cutting accident when connecting the relay wire 15 to the core wire 5 of the compensating conductor 6 by welding or filling the internal space of the outer sleeve 10 with heat-resistant cement. it can.
[0021]
In the second embodiment, the two total lengths of the two thermocouple wires 3 connected to the ends of the relay wires 15 are the same, and the two thermocouple wires 3 have the same length. Although the relay wire 15 is connected to the first filling material 9, the inclined opening end 8 a is formed such that the lengths of the portions embedded in the first filler 9 are equal to each other. By doing so, the length of the portion where the two relay wires 15 protrude from the inclined opening end 8a can be made the same, and therefore, the second filler 11 is filled in the internal space of the outer sleeve 10. At this time, the strength of the two relay wires 15 protruding from the inclined opening end 8a with respect to the maintenance of the insulation interval and the bending can be the same, and the quality level can be kept constant.
[0022]
Further, in the second embodiment, similarly to the first embodiment, a core wire movement suppressing bracket 7 is provided. Also, the two core wires 5 exposed from the ends of the compensating lead wire 6 are connected to the two relay wires 15 protruding from the inclined opening end 8a of the inner sleeve 8 as their connection partners, respectively. 10, the inner space of the outer sleeve 10 is filled with the second filler 11, and together with the inner sleeve 8, the core wire movement suppressing fitting 7, the end of the compensating lead 6, the compensating lead 6 The core wire 5, the connecting portion 17 between the relay wire 15 and the core wire 5 of the compensating conductor 6, and the relay wire 15 protruding from the inclined open end 8a of the inner sleeve 8 are fixed in the inner space of the outer sleeve 10. As the second filler 11, a heat-resistant cement is used as in the first embodiment.
[0023]
As is clear from the above structure, the sheath thermocouple of the second embodiment also has the same operation and effect as the sheath thermocouple of the first embodiment, in addition to the operation and effect of the relay wire 15 described above.
[0024]
In the sheath thermocouple of the first embodiment or the second embodiment, soda barium glass is used as the first filler, but lead glass or another glass may be used. In this case, it is desirable that the coefficient of thermal expansion of these glasses be close to the coefficient of thermal expansion of the material of the inner sleeve. Further, the first filler is not limited to glass, and any filler having excellent heat resistance and airtightness may be used. Although the heat-resistant cement is used as the second filler, any filler can be used as long as the filler can fix the embedded object in the internal space of the outer sleeve and has heat resistance.
[0025]
【The invention's effect】
According to the first aspect of the present invention, the inner sleeve having an inclined open end formed by a slope that crosses in the axial direction is used to connect the sheath of the sheath thermocouple and the compensating conductor. It becomes possible to fill the sleeve with the first filler excellent in heat resistance and airtightness, and by embedding the end face of the end of the sheath in the first filler excellent in heat resistance and airtightness, Since moisture absorption from the end face of the end of the sheath can be prevented, a sheath thermocouple that can be used at a high temperature can be provided.
[0026]
According to the second aspect of the invention, in addition to the effects of the first aspect of the invention, the following effects are provided. In the connection between the sheath of the sheath thermocouple and the compensating conductor, the thermocouple wire is connected to a relay wire of the same material as this thermocouple wire and larger than the thermocouple wire. Even when filling the inner space of the inner sleeve, the junction wire is less fragile even if oxidized by the heat of melting the filler compared to the thermocouple wire, and when connecting the junction wire to the core of the compensating conductor Also, it is possible to provide a sheath thermocouple that can prevent a cutting accident when filling the heat-resistant cement into the inner space of the outer sleeve.
[0027]
According to the third or fourth aspect of the present invention, in the connection between the sheath of the sheath thermocouple and the compensating conductor, glass having excellent heat resistance and airtightness is used as the first filler to be filled in the inner sleeve. Can be provided.
[0028]
According to the fifth or sixth aspect of the present invention, in the connection between the sheath of the sheath thermocouple and the compensating conductor, the first filler used to fill the inner space of the outer sleeve is filled in the inner sleeve. Since the filler having a higher heat resistance than the filler of the above is used, it is possible to ensure that the filler can be used up to the heat resistant temperature of the first filler to be filled in the inner sleeve, and it is also possible to use thermal and mechanical materials. A sheath thermocouple excellent in impact resistance can be provided.
[0029]
According to the invention described in claim 7, in the connection between the sheath of the sheath thermocouple and the compensating conductor, the core movement suppressing means for suppressing the core of the compensating conductor from moving in the axial direction inside the compensating conductor is provided externally. Since it is provided on the compensating conductor located in the internal space of the sleeve, when the compensating conductor is laid, when the compensating conductor is bent, the core wire moves in the axial direction inside the compensating conductor, so that the thermocouple It is possible to provide a sheath thermocouple capable of preventing a connection portion between a strand and a core wire from being damaged or deformed by applying a compressive stress or a tensile stress to the connection portion.
[0030]
According to the invention described in claim 8 or 9, in the connection between the sheath of the sheath thermocouple and the compensating conductor, the length of the portion where the two thermocouple wires or the two relay wires protrude from the inclined open end. Therefore, when filling the inner space of the outer sleeve with the second filler, two thermocouple wires or two relay wires projecting from the inclined open end are used. It is possible to provide a sheath thermocouple that can maintain the same insulation strength and the same strength against bending or the like and can maintain a constant quality level.
[Brief description of the drawings]
FIG. 1A is a vertical sectional view of a connecting portion in a sheath thermocouple of a first embodiment, and FIG. 1B is a horizontal sectional view.
FIG. 2 (a) is a vertical sectional view of a connecting portion in a sheath thermocouple of a second embodiment, and FIG. 2 (b) is a horizontal sectional view.
FIG. 3 is a cross-sectional view of a connection portion in a conventional sheath thermocouple.
[Explanation of symbols]
1 Sheath thermocouple connection
2 sheath
2a End face of sheath end
3 Thermocouple strand
4. Connection between thermocouple wires and core wires
5 Core wire of compensating conductor
6 Compensation conductor
7 Core wire movement suppression bracket
8 Inner sleeve
8a Inclined open end of inner sleeve
9 First filler (soda barium glass)
10 External sleeve
11 Second filler (heat-resistant cement)
15 trunk line
16 Connection between thermocouple wires and relay wires
17 Connection part between relay wire and core wire of compensation conductor
21 Connecting part of sheath thermocouple
22 sheath
23 Thermocouple wire
24 Compensating conductor
25 core wire
26 Connection part
27 sleeve
27a Base end of sleeve
28 Epoxy resin
29 Insulation separator

Claims

In a sheath thermocouple in which the sheath of the sheath thermocouple and the compensating lead wire are connected in the inner space of the outer sleeve,
The outer sleeve has an open end at the base end on the compensation lead side in a cylindrical shape, and the other end is inserted into the sheath,
The other end of the inner sleeve, which is a sloped open end formed in a plane whose base end on the side of the compensating lead wire obliquely crosses in the axial direction, provided in the inner space of the outer sleeve, is inserted into the sheath. Then, while positioning the end of the sheath in the inner space of the inner sleeve, the two thermocouple wires exposed from the ends are projected from the inclined opening end, and are inserted into the inner space of the inner sleeve. Filling the first filler excellent in heat resistance and airtightness,
An end of the compensating wire is positioned in the inner space of the outer sleeve, and two core wires exposed from the ends are connected to the thermocouple wires, and a second wire is inserted in the inner space of the outer sleeve. A sheath thermocouple characterized by being filled with a filler.

In a sheath thermocouple in which the sheath of the sheath thermocouple and the compensating lead wire are connected via a relay wire in the internal space of the outer sleeve,
The outer sleeve has an open end at the base end on the compensation lead side in a cylindrical shape, and the other end is inserted into the sheath,
The other end of the inner sleeve, which is a sloped open end formed in a plane whose base end on the relay wire side crosses obliquely in the axial direction and is provided in the inner space of the outer sleeve, is inserted into the sheath. Then, the end of the sheath is positioned in the internal space of the inner sleeve, and the thermocouple element made of the same material as the thermocouple element is attached to the tip of two thermocouple elements exposed from the ends. The relay wire, which is thicker than the wire, is connected in the internal space of the inner sleeve, and the relay wire is projected from the inclined opening end. The first wire having excellent heat resistance and airtightness in the internal space of the internal sleeve. Filling material of
An end of the compensating conductor is positioned in the inner space of the outer sleeve, and two core wires exposed from the ends are connected to the relay wire, and a second filler is provided in the inner space of the outer sleeve. A sheath thermocouple characterized by being filled with.

The sheath thermocouple according to claim 1 or 2, wherein glass is used as the first filler.

The sheath thermocouple according to any one of claims 1 to 3, wherein the glass is made of soda barium glass or lead glass.

The sheath thermocouple according to any one of claims 1 to 4, wherein a filler having higher heat resistance than the first filler is used as the second filler.

The sheath thermocouple according to any one of claims 1 to 5, wherein a heat-resistant cement is used as the second filler.

The core wire of the compensating lead wire is provided with a core wire movement suppressing means for preventing the core wire from moving in the axial direction inside the compensating wire wire on the compensating wire wire located in the internal space of the outer sleeve. 7. The sheath thermocouple according to any one of 6.

The length of each of the two thermocouple wires is made equal, and the length of each of the two portions of the thermocouple wire buried in the first filler is made equal to each other. 8. The sheath thermocouple according to claim 1, wherein the inclined open end is formed in the sheath thermocouple.

While the total length of each of the two thermocouple wires to which the relay wire is connected is made equal, and the thermocouple wires to which the relay wire is connected, the first filler material contains The sheath thermocouple according to any one of claims 2 to 7, wherein the inclined open end is formed such that the lengths of the two buried portions are equal to each other.