JP2004198396A

JP2004198396A - Method for obtaining drift value of leak detector, method for obtaining zero-point fluctuation value, method for obtaining humidity correction coefficient, and method for calibrating leakage detector and the leakage detector

Info

Publication number: JP2004198396A
Application number: JP2003167252A
Authority: JP
Inventors: Akio Furuse; 昭男古瀬; Yoshifumi Uchiyama; 義史内山
Original assignee: Cosmo Instruments Co Ltd
Current assignee: Cosmo Instruments Co Ltd
Priority date: 2002-10-23
Filing date: 2003-06-12
Publication date: 2004-07-15

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for calibrating a leakage detector, which can precisely determine the presence or the absence of leakage, even in a condition when especially an object to be detected is wet, relating to the leakage detector. <P>SOLUTION: This method for the leakage detector includes carrying out of the steps of closing the opening part of the object to be inspected by a sealing jig, applying pressurized air inside the object to be measured in this closed state, measuring the change in the pressure of the air inside the object to be measured after the elapse of a prescribed period of time, determining the presence of the leakage when the decrease in the pressure of the air is large, and determining the absence of the leakage when the decrease in the pressure of the air is small, obtaining and storing a drift correction value, using a dried objected to be measured having no leakage for each temperature difference between the object to be measured and the sealing jig, and furthermore change in the vapor pressure in a state, in which the object to be measured is wet is measured so as to obtain the humidity correction coefficient k from this change in the vapor pressure. Accordingly, the drift correction and the humidity correction are carried out, according to the drift correction value and the humidity correction coefficient. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
この発明は各種の容器、エンジンのシリンダブロック、ガス器具などの洩れが有ってはならない機器の洩れの有無を検査する洩れ検査装置に関し、特に被検査体が濡れている状態でも正確に洩れの有無を判定することができる洩れ検査装置の校正方法及び装置を提案しようとするものである。
【０００２】
【従来の技術】
洩れ検査装置は被検査体に加圧した空気を封入し、その空気圧の変化を測定して洩れの有無を検査している。然し乍ら、空気は被検査体の温度、或は被検査体に接触する治具等の温度の影響を受け、洩れが無いのに洩れの有るような圧力変動（これをドリフトと称している）を来し、洩れの有無の判定を難しいものとしている。
このため、本出願人は従来より各種の洩れ検査方法及び洩れ検査装置のドリフト補正に関して各種の提案を行なってきた。
【０００３】
過去において提案したドリフト補正方法はドリフトの発生原因を被検査体に印加した加圧気体の温度変化（加圧印加時の断熱変化）が主な発生原因と見て被検査体に印加した空気の圧力変化からドリフト補正係数を導き出す手法を採っていた（例えば特許文献１）。
この特許文献１で提案したドリフト補正方法によれば校正モードにおいて、ドリフト補正係数を求めた条件の範囲に限れば適正にドリフト補正が働くのであるが、その条件の範囲から外れると、正しくドリフト補正が行なわれなくなる欠点がある。
【０００４】
この状況を解消すべく本出願人は被検査対の開口部を閉塞するシール治具と被検査体との温度差に着目し、この温度差がドリフト発生要因と特定し、校正モードにおいてこの温度差毎にドリフト補正値を求めてテーブルとして記憶し、検査モードではシール治具と被検査体との温度差を計測し、その温度差に従ってドリフト補正値をテーブルから読み出して補正するドリフト補正方法（特許文献２及び特許文献３）を提案した。
【０００５】
【特許文献１】
特開２００１−５０８５４公報
【特許文献２】
特開２００２−２２５９２公報
【特許文献３】
特開２００３−１０６９２３公報
【０００６】
【発明が解決しようとする課題】
本出願人が過去に提案した各種のドリフト補正方法によれば被検査体が完全に乾燥状態であればほぼ完全に正しいドリフト補正を行なうことができる。然し乍ら、被検査体が濡れた状態（わずかでも水滴が付着している状態）にある場合には誤って判定を下す状況が発生することが判明した。
例えばエンジンブロックの場合には加工が終了すると洗浄水により洗浄が行なわれ、洗浄工程を経て検査工程にまわされる。洗浄工程の終了時点で乾燥工程が設けられているが、短時間に完全な乾燥を行なうことは難しい、このため、エンジンブロックの内壁にわずかな水滴が付着した状況で洩れ検査を行なう場面が多々存在する。
【０００７】
液体の水滴は常時被検査体温度における飽和蒸気圧に向かって蒸発を続ける。つまり、被検査体内に水滴が付着している場合、仮に被検査体の温度が常温でその開口部分がシール治具で閉塞された状況でも水滴は被検査体温度における飽和蒸気圧に向かって蒸発を続ける。この結果、水滴が存在した場合は被検査体内の圧力はわずかではあるが上昇を続け、この蒸発による圧力上昇が存在するためわずかな洩れが有るにも係わらず「洩れ無し」とする誤った判定を下すおそれがある。
【０００８】
因みに図２４に温度対飽和蒸気圧の対応を示す（理科年表より抜粋）。この図から明らかなように、温度が１０℃の場合と、３０℃の場合とでは飽和蒸気圧は約４倍の違いがあるから被検査体の温度が高い場合程水滴の影響が大きいことが分かる。
この発明の目的は被検査体とシール治具との間に温度差があっても、また被検査体に水滴が付着した状態であっても正しくドリフト補正を行なうことができる洩れ検査装置のドリフト値取得方法・温度補正係数取得方法・ゼロ点変動値取得方法・洩れ検査装置の校正方法及びこの校正方法により校正されて動作する洩れ検査装置を提案しようとするものである。
【０００９】
【課題を解決するための手段】
この発明では先願（特許文献３）で提案したドリフト値取得方法において、校正モードでドリフト値を取得する際に用いる被検査体を洩れのない乾燥された被検査体に特定し、乾燥状態にある被検査体を用いてシール治具と被検査体との間の温度差毎にドリフト値を取得し、検査モードではこのドリフト値を用いて従前どおりドリフト補正を施す。
これと共に、この発明では校正モードにおいて乾燥状態にある被検査体に水滴を付着し、濡れ被検査体に変換し、この濡れ被検査体を用いて水滴から発生する蒸気圧を測定し、この蒸気圧を利用して湿度補正係数ｋを求め、検査モードでは各被検査体毎に蒸気圧を測定し、この蒸気圧を湿度補正係数ｋにより正規化して湿度補正値Ｍを求め、この湿度補正値Ｍを先にドリフト補正されたドリフト値から減算して湿度補正を施す点を特徴とするものである。
【００１０】
従って、この発明によればシール治具と被検査体との間の温度差によって発生するドリフトと、水滴から発生する蒸気圧によるドリフトの双方を補正することが出来、これにより信頼性の高い洩れ検査装置を提供することができる。
具体的な解決手段としては以下の如くである。
この発明では被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体の内部に空気圧を封じ込め、この空気圧の変化を測定して空気圧の低下量が大きいとき洩れ有り、空気圧の低下量が小さいとき洩れ無しと判定する洩れ検査装置において、
校正モードで被検査体に洩れの無い乾燥された常温乾燥被検査体を用意し、この常温乾燥被検査体とシール治具との間に所定の温度差を与えた状態に設定し、この所定の温度差が与えられている状態で常温乾燥被検査体に空気圧を印加し、その空気圧の変動量をドリフト値として測定することを複数の温度差毎に実行し、複数の温度差のドリフト値をドリフト記憶器に記憶する洩れ検査装置のドリフト値取得方法を提案する。
【００１１】
この発明では更に被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体と基準タンクに空気圧を封じ込め、両者間に圧力差が発生するか否かにより被検査体に洩れが有る否かを判定する洩れ検査装置において、
校正モードで被検査体に洩れの無い乾燥された常温乾燥被検査体を用意し、この常温乾燥被検査体とシール治具との間に所定の温度差を与えた状態に設定し、この所定の温度差が与えられている状態で常温乾燥被検査体と基準タンクに空気を封じ込め、圧力差の変動量をドリフト値として測定することを複数の温度差毎に実行し、複数の温度差のドリフト値をドリフト記憶器に記憶することを特徴とする洩れ検査装置のドリフト値取得方法を提案する。
【００１２】
この発明では更に洩れ検査装置のドリフト取得方法の何れかにより、ドリフト記憶器に被検査体とシール治具との間の温度差に対応するドリフト値を記憶した洩れ検査装置において、
校正モードで洩れの無い乾燥された常温乾燥被検査体を用意すると共に、この常温乾燥被検査体とシール治具との間の温度差を測定し、この温度差に対応するドリフト値をドリフト記憶器から導出すると共に、常温乾燥被検査体に空気圧を印加してドリフト値と環境温度を測定し、この測定して得られたドリフト値とドリフト記憶器から導出したドリフト値との偏差を求め、この偏差値を測定した環境温度に対応するゼロ点変動値としてゼロ点変動記憶器に記憶する洩れ検査装置のゼロ点変動値取得方法を提案する。
【００１３】
この発明では更に洩れ検査装置のドリフト値取得方法の何れかにより、ドリフト記憶器に被検査体とシール治具との間の温度差に対応するドリフト値を記憶した洩れ検査装置において、
校正モードで洩れの有無が不明な乾燥された常温乾燥被検査体を用意する共に、この洩れの有無が不明な乾燥された常温乾燥被検査体とシール治具との間の温度差をゼロの状態に設定し、この設定状態で被検査体に空気圧を印加して仮ドリフト値と環境温度とを測定すると共に、ドリフト測定タイミングより長時間経過したタイミングで洩れのみによる圧力変化を測定してこの圧力変化を仮ドリフト値から差し引くことにより真のドリフト値を求め、この求められたドリフト値とドリフト記憶器の温度差ゼロに該当するアドレスに記憶しているドリフト値との偏差を求め、この偏差値を測定した環境温度に対応するゼロ点変動値としてゼロ点変動記憶器に記憶する洩れ検査装置のゼロ点変動値取得方法を提案する。
【００１４】
この発明では更に洩れ検査装置のゼロ点変動値取得方法の何れかにおいて、
ゼロ点変動値取得方法で取得するゼロ点変動値を複数の環境温度毎に取得し、各環境温度毎に取得したゼロ点変動値をゼロ点変動値記憶器に記憶するゼロ点変動値取得方法を提案する。
この発明では更に被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体の内部に空気圧を印加し、所定時間が経過後の被検査体内部の空気圧の変化量を測定し、空気圧の低下量が大きいとき洩れ有り、空気圧の低下量が小さいとき洩れ無しと判定する洩れ検査装置の湿度補正係数取得方法において、
校正モードで洩れの無い常温乾燥被検査体を用意し、この常温乾燥被検査体の開口部分をシール治具により閉塞し、その閉塞状態で所定時間の経過後の被検査体の内部の圧力変化値をシール治具によるシール誤差値ΔＰ_０として計測する過程と、この常温乾燥被検査体に空気圧を印加し、空気圧の印加後の所定時間が経過する間の圧力変化値をドリフト値ΔＰ_０１として計測する過程と、常温乾燥被検査体の内面に水滴を付着させ常温乾燥被検査体を常温濡れ被検査体に変換する過程と、この常温濡れ被検査体の開口部をシール治具によって閉塞し、所定時間が経過する間の圧力変化値を蒸発空気圧ΔＰ_１として計測する過程と、上記常温濡れ被検査体に空気圧を印加し、空気圧の印加後の所定の時間が経過する間の空気圧変化値を濡れ被検査体のドリフト値ΔＰ_１１として計測する過程と、各計測値から湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）により求める過程と、シール誤差値ΔＰ_０と湿度補正係数ｋを記憶器に記憶する過程とを実行する洩れ検査装置の湿度補正係数取得方法を提案する。
【００１５】
この発明では更に被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体と基準タンクに空気圧を印加し、両者間に圧力差が発生するか否かにより被検査体に洩れが有るか否かを判定する濡れ検査装置の補正係数取得方法において、
校正モードで洩れの無い常温乾燥被検査体を用意し、この常温乾燥被検査体の開口部分をシール治具により閉塞し、その閉塞状態で所定時間の経過後の常温乾燥被検査体と基準タンクとの間に発生する差圧値をシール治具によるシール誤差値ΔＰ_０として計測する過程と、上記常温乾燥被検査体と基準タンクに空気圧を印加し、空気圧の印加後の所定時間が経過する間に発生する差圧値をドリフト値ΔＰ_０１として計測する過程と、常温乾燥被検査体の内面に水滴を付着させ上記常温乾燥被検査体を常温濡れ被検査体に変換する過程と、この常温濡れ被検査体の開口部を上記シール治具によって閉塞し、所定時間が経過する間の差圧の変化値を蒸発空気圧ΔＰ_１として計測する過程と、常温濡れ被検査体及び基準タンクに空気圧を印加し、空気圧の印加後の所定の時間が経過する間の差圧の変化値を濡れ被検査体のドリフト値ΔＰ_１１として計測する過程と、各計測値から湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）により求める過程と、シール誤差値ΔＰ_０と湿度補正係数ｋを記憶器に記憶する過程とを実行する洩れ検査装置の湿度補正係数取得方法を提案する。
【００１６】
この発明では更に濡れ検査装置の湿度補正係数取得方法の何れかによりシール誤差値ΔＰ_０と湿度補正係数ｋを記憶した洩れ検査装置の湿度補正方法において、
検査モードで被検査体の開口部分をシール治具により閉塞し、この閉塞状態で被検査体の内部の圧力変化値又は被検査体と基準タンクとの間に発生する差圧値がΔＰ_Ｘとして計測された場合、湿度補正値ＭをＭ＝（ΔＰ_Ｘ−ΔＰ_０）ｋにより算出し、この湿度補正値Ｍを洩れ検査時に発生するドリフト値から除去して湿度補正を施す洩れ検査装置の湿度補正方法を提案する。
【００１７】
この発明では更に洩れ検査装置のドリフト値取得方法によりドリフト記憶器に被検査体とシール治具間の温度差に対応したドリフト値を記憶すると共に、請求項６記載の洩れ検査装置の湿度補正係数取得方法によりシール誤差値ΔＰ_０と湿度補正係数ｋとを記憶した洩れ検査装置の洩れ検査方法又は請求項２記載の洩れ検査装置のドリフト値取得方法によりドリフト記憶器に被検査体とシール治具間の温度差に対応したドリフト値を記憶すると共に、請求項７記載の洩れ検査装置の湿度補正係数取得方法によりシール誤差値ΔＰ_０と湿度補正係数ｋとを記憶した洩れ検査装置の洩れ検査方法の何れかにおいて、
検査モードでは被検査体とシール治具との間の温度差を測定し、その温度差に対応したドリフト補正値をドリフト記憶器から読み出し、このドリフト値を被検査体に封入された空気圧の変化量から減算し、洩れ検査時に発生するドリフト成分を除去すると共に、被検査体の開口部を大気圧の環境下においてシール治具で密封し、その密封状態から所定時間を経過した時点までの圧力変化値ΔＰ_Ｘを測定し、この圧力変化値ΔＰ_Ｘからシール誤差値ΔＰ_０を減算した値（ΔＰ_Ｘ−ΔＰ_０）に湿度補正係数ｋを乗算して検査モードにおける湿度補正値ＭをＭ＝（ΔＰ_Ｘ−ΔＰ_０）ｋで求め、この湿度補正値Ｍを上記ドリフト成分を除去した空気圧の変化量から減算し、この減算結果と洩れの有無を判定する判定値とを比較する洩れ検査方法を提案する。
【００１８】
この発明では更に被検査体の開口部を閉塞するシール治具と、このシール治具と被検査体との間の温度差を測定する温度センサと、被検査体の内部の空気圧の変化を測定する圧力センサと、校正モードにおいて洩れの無い常温乾燥被検査体と上記シール治具との間の温度差毎に常温乾燥被検査体の内部で発生する圧力変化をドリフト値として取得するドリフト値取得手段と、このドリフト値取得手段が取得した各温度差毎のドリフト値を記憶するドリフト記憶器と、校正モードにおいて洩れの無い常温濡れ被検査体の開口部を大気圧の環境下においてシール治具で閉塞し、その閉塞状態で圧力センサで計測される圧力変化からシール誤差値ΔＰ_０を測定するシール誤差測定手段と、このシール誤差測定手段が測定したシール誤差値ΔＰ_０を記憶するシール誤差記憶器と、校正モードにおいて洩れの無い常温濡れ被検査体の開口部を大気圧の環境下においてシール治具で閉塞し、その閉塞状態で圧力センサで計測される圧力変化値ΔＰ_１と、常温乾燥被検査体に空気圧を印加し、所定の時間が経過する間に発生する常温乾燥被検査体の内部の圧力変化値ΔＰ_０１と、常温濡れ検査体に空気圧を印加し、所定の時間が経過する間に発生する常温濡れ被検査体の内部の圧力変化値ΔＰ_１１とをそれぞれ計測し、これらの計測結果と、シール誤差値ΔＰ_０とにより湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）によって求める湿度補正係数取得手段と、この湿度補正係数取得手段で取得した湿度補正係数ｋを記憶する湿度補正係数記憶器と、検査モードにおいて、温度センサにより測定した被検査体とシール治具との間の温度差に対応したドリフト値をドリフト記憶器から読み出すドリフト書込読出手段と、検査モードにおいて、被検査体の開口部を大気圧の環境下でシール治具によって閉塞し、この閉塞期間における被検査体の内部の圧力変化を計測する湿度補正のための蒸気圧測定手段と、この蒸気圧測定手段で測定した測定値ΔＰ_Ｘからシール誤差値ΔＰ_０を減算し、その減算値（ΔＰ_Ｘ−ΔＰ_０）に湿度補正係数ｋを乗算して湿度補正値Ｍを求める湿度補正値算出手段と、検査モードにおいて、被検査体に封じ込めた空気圧の変化量からドリフト書込読出手段が読み出したドリフト値と湿度補正値Ｍとを減算し、ドリフト補正と湿度補正を施す減算手段と、この減算手段で減算した結果と設定値とを比較し、被検査体の洩れの有無を判定する判定手段とによって構成した洩れ検査装置を提案する。
【００１９】
この発明では更に被検査体の開口部を閉塞するシール治具と、このシール治具と被検査体との間の温度差を測定する温度センサと、被検査体と基準タンクとの間に発生する差圧の変化を測定する差圧センサと、校正モードにおいて洩れの無い常温乾燥被検査体とシール治具との間の温度差毎に常温乾燥被検査体と基準タンクとの間に発生する差圧変化をドリフト値として取得するドリフト値取得手段と、このドリフト値取得手段が取得した各温度差毎のドリフト値を記憶するドリフト記憶器と、校正モードにおいて洩れの無い常温乾燥被検査体の開口部を大気圧の環境下においてシール治具で閉塞し、その閉塞状態で差圧センサで計測される差圧変化からシール誤差値ΔＰ_０を測定するシール誤差測定手段と、このシール誤差測定手段が測定したシール誤差値ΔＰ_０を記憶するシール誤差記憶器と、校正モードにおいて洩れの無い常温濡れ被検査体の開口部を大気圧の環境下においてシール治具で閉塞し、その閉塞状態で差圧センサで計測される差圧変化値ΔＰ_１と、常温乾燥被検査体と基準タンクに空気圧を印加し、所定の時間が経過する間に発生する常温乾燥被検査体と基準タンクの間の差圧変化値ΔＰ_０１と、常温濡れ検査体に空気圧を印加し、所定の時間が経過する間に常温濡れ被検査体と基準タンクの差圧変化値ΔＰ_１１とをそれぞれ計測し、これらの計測結果と、シール誤差値ΔＰ_０とにより湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）によって求める湿度補正係数取得手段と、この湿度補正係数取得手段で取得した湿度補正係数ｋを記憶する湿度補正係数記憶器と、検査モードにおいて、温度センサにより測定した被検査体とシール治具との間の温度差に対応したドリフト値をドリフト記憶器から読み出すドリフト書込読出手段と、検査モードにおいて、被検査体の開口部を大気圧の環境下でシール治具によって閉塞し、この閉塞期間における被検査体の内部の圧力変化を計測する湿度補正のための蒸気圧測定手段と、この蒸気圧測定手段で測定した測定値ΔＰ_Ｘからシール誤差値ΔＰ_０を減算し、その減算値（ΔＰ_Ｘ−ΔＰ_０）に湿度補正係数ｋを乗算して湿度補正値Ｍを求める湿度補正値算出手段と、検査モードにおいて、被検査体に封じ込めた空気圧の変化量からドリフト書込読出手段が読み出したドリフト値と湿度補正値Ｍとを減算し、ドリフト補正と湿度補正を施す減算手段と、この減算手段で減算した結果と設定値とを比較し、被検査体の洩れの有無を判定する判定手段とによって構成した洩れ検査装置を提案する。
【００２０】
この発明では更に被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体の内部に空気圧を印加し、所定時間が経過後の上記被検査体内部の空気圧の変化量を測定し、空気圧の低下量が大きいとき洩れ有り、空気圧の低下量が小さいとき洩れ無しと判定する洩れ検査装置又は被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体と基準タンクに空気圧を印加し、両者間に圧力差が発生するか否かにより上記被検査体に洩れが有るか否かを判定する洩れ検査装置の湿度補正係数取得方法の何れかにおいて、校正モードで洩れの無い常温乾燥被検査体を用意し、この常温乾燥被検査体の外側面に閉塞された空間を形成するための計測用治具をシール治具を介して被着し、この閉塞された空間を所定時間閉塞し、その閉塞状態で所定時間の経過後の圧力変化値をシール治具によるシール誤差値ΔＰ_０として計測する過程と、この常温乾燥被検査体に空気圧を印加し、空気圧の印加後の所定時間が経過する間の圧力変化値をドリフト値ΔＰ_０１として計測する過程と、上記計測治具が形成する空間に面する上記常温乾燥被検査体の内面と外面に均一に水滴を付着させ上記常温乾燥被検査体を常温濡れ被検査体に変換する過程と、この常温濡れ被検査体の濡れた部分を上記計測治具により覆って閉塞し、所定時間が経過する間の圧力変化値を蒸気圧ΔＰ_１として計測する過程と、上記常温濡れ被検査体に空気圧を印加し、空気圧の印加後の所定の時間が経過する間の空気圧変化値を濡れ被検査体のドリフト値ΔＰ_１１として計測する過程と、上記各計測値から湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）により求める過程と、上記シール誤差値ΔＰ_０と湿度補正係数ｋを記憶器に記憶する過程とを実行する洩れ検査装置の湿度補正係数取得方法を提案する。
【００２１】
この発明では更に洩れ検査装置の湿度補正係数取得方法によりシール誤差値ΔＰ_０と湿度補正係数ｋを記憶した洩れ検査装置の湿度補正方法において、検査モードで被検査体の外表面の一部を上記計測冶具により覆って閉塞空間を形成し、所定時間が経過する間の上記閉塞空間内の圧力変化値をΔＰ_Ｘとして計測された場合、湿度補正値ＭをＭ＝（ΔＰ_Ｘ−ΔＰ_０）ｋにより算出し、この湿度補正値Ｍを洩れ検査時に発生するドリフト値から除去して湿度補正を施す洩れ検査装置の湿度補正方法を提案する。
【００２２】
この発明では更に洩れ検査装置のドリフト値取得方法によりドリフト記憶器に被検査体とシール治具間の温度差に対応したドリフト値を記憶すると共に、請求項１２記載の洩れ検査装置の湿度補正係数取得方法によりシール誤差値ΔＰ_０と湿度補正係数ｋとを記憶した洩れ検査装置の洩れ検査方法又は請求項２記載の洩れ検査装置のドリフト値取得方法によりドリフト記憶器に被検査体とシール治具間の温度差に対応したドリフト値を記憶すると共に、請求項１２記載の洩れ検査装置の湿度補正係数取得方法によりシール誤差値ΔＰ_０と湿度補正係数ｋとを記憶した洩れ検査装置の洩れ検査方法の何れかにおいて、検査モードでは被検査体とシール治具との間の温度差を測定し、その温度差に対応したドリフト補正値を上記ドリフト記憶器から読み出し、このドリフト値を被検査体に封入された空気圧の変化量から減算し、洩れ検査時に発生するドリフト成分を除去すると共に、被検査体の外表面の一部を上記計測冶具により覆って閉塞し、大気圧の環境下において密封し、その密封状態から所定時間を経過した時点までの圧力変化値ΔＰ_Ｘを測定し、この圧力変化値ΔＰ_Ｘから上記シール誤差値ΔＰ_０を減算した値（ΔＰ_Ｘ−ΔＰ_０）に上記湿度補正係数ｋを乗算して検査モードにおける湿度補正値ＭをＭ＝（ΔＰ_Ｘ−ΔＰ_０）ｋで求め、この湿度補正値Ｍを上記ドリフト成分を除去した空気圧の変化量から減算し、この減算結果と洩れの有無を判定する判定値とを比較する洩れ検査方法提案する。
【００２３】
この発明では更に被検査体の開口部を閉塞するシール治具と、このシール治具と被検査体との間の温度差を測定する温度センサと、上記被検査体の内部の空気圧の変化を又は被検査体と基準タンクとの間に発生する圧力差を測定する圧力センサと、校正モードにおいて洩れの無い常温乾燥被検査体と上記シール治具との間の温度差毎に上記常温乾燥被検査体の内部で発生する圧力変化をドリフト値として取得するドリフト値取得手段と、このドリフト値取得手段が取得した上記各温度差毎のドリフト値を記憶するドリフト記憶器と、校正モードにおいて洩れの無い常温乾燥被検査体の外側に被着され、凹部により閉塞された空間を形成する計測治具と、この計測治具で形成される空間を閉塞し、その閉塞状態で蒸気圧測定用圧力センサで計測される圧力変化からシール誤差値ΔＰ_０を測定するシール誤差測定手段と、このシール誤差測定手段が測定したシール誤差値ΔＰ_０を記憶するシール誤差記憶器と、校正モードにおいて洩れの無い常温濡れ被検査体を大気圧の環境下において上記計測用治具で閉塞し、その閉塞状態で上記蒸気圧測定用圧力センサで計測される圧力変化値ΔＰ_１と、上記常温乾燥被検査体に空気圧を印加し、所定の時間が経過する間に発生する上記常温乾燥被検査体の内部の圧力変化値ΔＰ_０１と、上記常温濡れ検査体に空気圧を印加し、所定の時間が経過する間に発生する上記常温濡れ被検査体の内部の圧力変化値ΔＰ_１１とをそれぞれ計測し、これらの計測結果と、上記シール誤差値ΔＰ_０とにより湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）によって求める湿度補正係数取得手段と、この湿度補正係数取得手段で取得した湿度補正係数ｋを記憶する湿度補正係数記憶器と、検査モードにおいて、上記温度センサにより測定した被検査体とシール治具との間の温度差に対応したドリフト値を上記ドリフト記憶器から読み出すドリフト書込読出手段と、検査モードにおいて、上記計測治具で形成される空間を大気圧の環境下で閉塞し、この閉塞期間における上記空間の内部の圧力変化を計測する湿度補正のための蒸気圧測定手段と、この蒸気圧測定手段で測定した測定値ΔＰ_Ｘから上記シール誤差値ΔＰ_０を減算し、その減算値（ΔＰ_Ｘ−ΔＰ_０）に上記湿度補正係数ｋを乗算して湿度補正値Ｍを求める湿度補正値算出手段と、検査モードにおいて、上記被検査体に封じ込めた空気圧の変化量から上記ドリフト書込読出手段が読み出したドリフト値と上記湿度補正値Ｍとを減算し、ドリフト補正と湿度補正を施す減算手段と、この減算手段で減算した結果と設定値とを比較し、被検査体の洩れの有無を判定する判定手段とによって構成した洩れ検査装置を提案する。
【００２４】
この発明では更に被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体の内部に空気圧を印加し、所定時間が経過後の上記被検査体内部の空気圧の変化量を測定し、空気圧の低下量が大きいとき洩れ有り、空気圧の低下量が小さいとき洩れ無しと判定する洩れ検査装置又は被検査体の開口部分をシール治具によって閉塞し、この閉塞状態で被検査体と基準タンクに空気圧を印加し、両者間に圧力差が発生するか否かにより上記被検査体に洩れが有るか否かを判定する洩れ検査装置の湿度補正係数取得方法の何れかにおいて、校正モードで洩れの無い常温乾燥被検査体を用意し、この常温乾燥被検査体に空気圧を印加し、空気圧の印加後の所定時間が経過する間の圧力変化値をドリフト値ΔＰ_０１として計測する過程と、上記常温乾燥被検査体の外面と、上記常温乾燥被検査体の内面に均一に水滴を付着させ上記常温乾燥被検査体を常温濡れ被検査体に変換する過程と、この常温濡れ被検査体の濡れた部分を計測治具により覆って閉塞空間を形成し、この閉塞空間に、所定の負圧を印加し、負圧の印加後所定時間が経過する間の上記閉塞空間内の圧力変化値を蒸気圧ΔＰ_１として計測する過程と、上記常温濡れ被検査体に空気圧を印加し、空気圧の印加後の所定の時間が経過する間の空気圧変化値を濡れ被検査体のドリフト値ΔＰ_１１として計測する過程と、上記各計測値から湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／ΔＰ_１）により求める過程と、上記湿度補正係数ｋを記憶器に記憶する過程とを実行する洩れ検査装置の湿度補正係数取得方法を提案する。
この発明では更に洩れ検査装置の湿度補正係数取得方法により湿度補正係数ｋを記憶した洩れ検査装置の湿度補正方法において、検査モードで被検査体の外表面の一部を上記計測冶具によって覆って閉塞空間を形成し、所定時間が経過する間の上記閉塞空間内の圧力変化値をΔＰ_Ｘとして計測された場合、湿度補正値ＭをＭ＝ΔＰ_Ｘ _・ｋにより算出し、この湿度補正値Ｍを洩れ検査時に発生するドリフト値から除去して湿度補正を施す洩れ検査装置の湿度補正方法を提案する。
【００２５】
この発明では更に洩れ検査装置のドリフト値取得方法によりドリフト記憶器に被検査体とシール治具間の温度差に対応したドリフト値を記憶すると共に、請求項１６記載の洩れ検査装置の湿度補正係数取得方法により湿度補正係数ｋを記憶した洩れ検査装置の洩れ検査方法又は請求項２記載の洩れ検査装置のドリフト値取得方法によりドリフト記憶器に被検査体とシール治具間の温度差に対応したドリフト値を記憶すると共に、請求項１６記載の洩れ検査装置の湿度補正係数取得方法により湿度補正係数ｋを記憶した洩れ検査装置の洩れ検査方法の何れかにおいて、検査モードでは被検査体とシール治具との間の温度差を測定し、その温度差に対応したドリフト補正値を上記ドリフト記憶器から読み出し、このドリフト値を被検査体に封入された空気圧の変化量から減算し、洩れ検査時に発生するドリフト成分を除去すると共に、被検査体と計測冶具によって形成される閉塞空間を負圧の環境下において密封し、その密封状態から所定時間を経過した時点までの閉塞空間内の圧力変化値ΔＰ_Ｘを測定し、この圧力変化値ΔＰ_Ｘに上記湿度補正係数ｋを乗算して検査モードにおける湿度補正値ＭをＭ＝ΔＰ_Ｘ・ｋで求め、この湿度補正値Ｍを上記ドリフト成分を除去した空気圧の変化量から減算し、この減算結果と洩れの有無を判定する判定値とを比較する洩れ検査方法を提案する。
【００２６】
この発明では更に被検査体の開口部を閉塞するシール治具と、このシール治具と被検査体との間の温度差を測定する温度センサと、上記被検査体の内部の空気圧の変化を又は被検査体と基準タンクとの間に発生する圧力差を測定する圧力センサと、校正モードにおいて洩れの無い常温乾燥被検査体と上記シール治具との間の温度差毎に上記常温乾燥被検査体の内部で発生する圧力変化をドリフト値として取得するドリフト値取得手段と、このドリフト値取得手段が取得した上記各温度差毎のドリフト値を記憶するドリフト記憶器と、校正モードにおいて洩れの無い常温乾燥被検査体の外側に被着され、凹部により閉塞された空間を形成する計測治具と、校正モードにおいて洩れの無い常温濡れ被検査体の外表面の一部を上記計測用治具で被覆し、上記計測冶具で形成される閉塞空間に負圧を印加し、この負圧の印加状態で所定の時間が経過する間に上記蒸気圧測定用圧力センサで計測される圧力変化値ΔＰ_１と、上記常温乾燥被検査体に空気圧を印加し、所定の時間が経過する間に発生する上記常温乾燥被検査体の内部の圧力変化値ΔＰ_０１と、上記常温濡れ検査体に空気圧を印加し、所定の時間が経過する間に発生する上記常温濡れ被検査体の内部の圧力変化値ΔＰ_１１とをそれぞれ計測し、これらの計測結果により湿度補正係数ｋをｋ＝（ΔＰ_１１−ΔＰ_０１）／ΔＰ_１によって求める湿度補正係数取得手段と、この湿度補正係数取得手段で取得した湿度補正係数ｋを記憶する湿度補正係数記憶器と、検査モードにおいて、上記温度センサにより測定した被検査体とシール治具との間の温度差に対応したドリフト値を上記ドリフト記憶器から読み出すドリフト書込読出手段と、検査モードにおいて、上記計測治具で形成される空間に負圧を印加し、この負圧印加状態で上記空間の内部の圧力変化を計測する湿度補正のための蒸気圧測定手段と、この蒸気圧測定手段で測定した測定値ΔＰ_Ｘに上記湿度補正係数ｋを乗算して湿度補正値Ｍを求める湿度補正値算出手段と、検査モードにおいて、上記被検査体に封じ込めた空気圧の変化量から上記ドリフト書込読出手段が読み出したドリフト値と上記湿度補正値Ｍとを減算し、ドリフト補正と湿度補正を施す減算手段と、この減算手段で減算した結果と設定値とを比較し、被検査体の洩れの有無を判定する判定手段とによって構成した洩れ検査装置を提案する。
この発明では更に洩れ検査装置の何れかにおいて、検査モードで上記温度センサが測定した被検査体とシール治具との間の温度差に対応したドリフト値が上記ドリフト記憶器に存在しない場合は、上記ドリフト記憶器に記憶されている複数のドリフト値から直線近似により該当する温度差に対応するドリフト値を算出する直線近似演算手段を設けた構成とした洩れ検査装置を提案する。
【００２７】
作用
この発明による洩れ検査装置のドリフト値取得方法によれば、被検査体とシール治具との間の温度差をドリフト発生要因として特定し、被検査体とシール治具間の温度差毎にドリフト値を取得し、ドリフト記憶器に記憶したから、ドリフト記憶器に用意したドリフト値と、検査モードで発生するドリフト値とが良く一致し、精度の高いドリフト補正を施すことができる利点が得られる。また、この発明による洩れ検査装置の湿度補正値取得方法を適用することにより、水滴が付着した状態の被検査体であっても予め湿度補正値を取得してあるから検査前又は検査終了時点を除く検査中の何れかにおいて、その検査すべき被検査体の蒸発空気圧を測定すれば、その測定値から湿度補正値を求めることができる。この結果、被検査体とシール治具間の温度差に基づいて発生するドリフトも、水滴の付着によって発生する蒸気圧による誤差も検査結果で得られるドリフト値から除去できるから、水滴がわずかでも付着した被検査体でも正しく検査を行なうことができる。
【００２８】
【発明の実施の形態】
図１にこの発明による洩れ検査装置の一実施例を示す。この洩れ検査装置によればこの発明による洩れ検査用のドリフト値取得方法及び湿度補正係数取得方法を実行することができる。また、このドリフト値取得方法で取得したドリフト値及び湿度補正係数取得方法で取得した湿度補正係数を利用して信頼性の高い洩れ検査を実行することができる。
図中Ｗは被検査体を示す。被検査体Ｗは基台となる第１シール治具１の上に載置され、オーリングのようなシール部材ＣＣで気密を保持される。被検査体Ｗの上部側の開口部には第２シール治具２が搭載され、被検査体Ｗの上部側の開口部を閉塞する。この場合第２シール治具２に装着されたシール部材ＣＣで気密を保持して閉塞する。
【００２９】
被検査体Ｗは例えばエンジンのシリンダブロック或はガス器具の部品等各種の製品が適用される。エンジンのシリンダブロックのように形状が大きい場合は中子１４を挿入し、被検査体Ｗ内の内容積を可及的に小さくするように配慮される。
第２シール治具２には空気の注入口２Ａが設けられ、この注入口２Ａに配管１５が連通される。配管１５には圧力センサ１６と、電磁弁１７と、３方電磁弁１８と、調圧弁１９を通じて空圧源２０が接続される。調圧弁１９を調整して圧力計２１の指示に従って被検査体Ｗに印加する空気圧を設定する。
【００３０】
３方電磁弁１８をａ−ｂ間を開放状態に制御し、電磁弁１７を開くことにより被検査体Ｗに空気圧を印加することができる。被検査体Ｗに空気圧を印加した後で電磁弁１７を閉じることにより、被検査体Ｗに空気圧を封じ込めることができる。この封じ込んだ空気圧を圧力センサ１６で測定することにより所定の時間に渡って一定値を維持すれば洩れ無しと判定することができる。
然し乍ら、一般的には被検査体Ｗと第１シール治具１及び第２シール治具２の温度に対応して空気圧が変動（ドリフト）し、あたかも洩れが有るかの如く挙動する。更に、そのドリフト量は被検査体Ｗが乾燥状態にある場合と、濡れている場合とで異なる値を呈する。
【００３１】
このため、この発明では被検査体Ｗが乾燥状態にあることを想定して施すドリフト補正を実行するドリフト補正手段と、濡れた状態を想定して施す湿度補正を実行する湿度補正手段とを備えた洩れ検査装置を提供するものである。図１に示す洩れ検査装置本体１００は概略ドリフト補正手段３０と湿度補正手段５０と、判定手段７０とを備えた洩れ検査装置本体を示す。この発明による洩れ検査装置本体１００の内部の詳細は図２で説明することにするが、ここでは洩れ検査装置本体１００の概要を説明する。
【００３２】
ドリフト補正手段３０には予め校正モードにおいて取得したドリフト補正値を記憶しているドリフト記憶器３０Ｂが設けられる。このドリフト記憶器３０Ｂに記憶されているドリフト補正値は洩れの無い乾燥状態にある被検査体Ｗを用意する。この洩れの無い被検査体には洩れの有無を検査すべき製品と同一形状で、同一の材質であることが要件として求められる。この被検査体Ｗに空気圧を印加し、空気圧の印加後、所定の安定時間を経て、所定の測定期間（例えば２〜４秒程）を設定し、この測定期間に被検査体Ｗの内部の圧力変化をドリフト値として取得する。このとき、被検査体Ｗと第１シール治具１との間の温度差を測定し、その温度差におけるドリフト値としてドリフト記憶器３０Ｂに記憶する。校正モードでは被検査体Ｗを加熱又は冷却して被検査体Ｗと第１シール治具１との間の温度差を異なる温度差に設定し、各温度差毎にドリフト値を取得し、その取得したドリフト値をドリフト記憶器３０Ｂに記憶する。
【００３３】
被検査体Ｗとシール治具（図１に示す例では第１シール治具１）との間の温度差を測定するために、第１シール治具１に温度センサ３を設けている。この温度センサ３は図３に示すように第１シール治具１の被検査体Ｗと接触する面に穴Ｈを形成し、この穴Ｈの内部にセンサホルダ１３を装着する。センサホルダ１３は軸芯に貫通孔１３Ａを有し、この貫通孔１３Ａの両端に温度センサＳ１、Ｓ２を装着して支持させる。温度センサＳ１、Ｓ２は貫通孔１３Ａの両端面に露出して配置し、温度センサＳ１は第１シール治具１に接触して第１シール治具１の温度を測定する、また、センサＳ２は貫通孔１３Ａの上端面に露出して配置される。これらセンサＳ１とＳ２は貫通孔１３Ａの内部で樹脂剤或は接着剤等でセンサホルダ１３に固定される。
【００３４】
温度センサＳ２は第１シール治具１の表面と面一に配置され、その上に被検査体Ｗを搭載すると、被検査体ＷがセンサＳ２に接触し、被検査体Ｗの温度を測定する。尚、センサＳ２の表面には保護のために銅のような熱伝導率の高い材質の金属板等を配置し、この金属板を介して被検査体Ｗに接触するように構成することもできる。
温度差測定器４はセンサＳ１とＳ２の測定温度の差を求め、被検査体Ｗと第１シール治具１との間の温度差を洩れ検査装置本体１００に入力する。
【００３５】
このようにしてドリフト記憶器３０Ｂには校正モードにおいて予め被検査体Ｗとシール治具１との間の温度差毎に取得したドリフト値が記憶される。
検査モードでは検査に先だって被検査体Ｗとシール治具１との間の温度差を測定し、その温度差に対応したドリフト値をドリフト記憶器３０Ｂから読み出し、このドリフト値を被検査体を検査した場合に発生するドリフト値から減算してドリフト補正を施す。
一方、湿度補正値算出手段５０には湿度補正係数取得手段５０Ｃと、湿度補正係数記憶器５０Ｄと、被検査体Ｗに水滴が付着している度合を測定する蒸気圧測定手段５０Ｅとが設けられている。湿度補正係数取得手段５０Ｃには、予め校正モードにおいて常温乾燥状態にある洩れの無い被検査体と、水滴を付着した濡れた常温被検査体とを用いてそれぞれの被検査体で発生するドリフト値を測定し、そのドリフト値から湿度補正係数ｋを取得し、この湿度補正係数ｋを湿度補正係数記憶器５０Ｄに記憶して用意する。
【００３６】
これと共に検査モードでは蒸気圧測定手段５０Ｅにより各被検査体毎に水滴が存在する場合に発生する蒸気圧を測定し、この蒸気圧と湿度補正係数ｋとにより湿度補正値Ｍを求め、この湿度補正値Ｍを被検査体で発生するドリフト値（詳しくはドリフト補正が施されたドリフト値）から減算し、湿度補正を施す。
判定手段７０はドリフト補正と湿度補正が施されたドリフト値と予め設定した判定値とを比較し、ドリフト値が判定値を超えている場合を洩れ有り、判定値以下の場合を洩れ無しと判定し、その判定結果を表示器２００に表示する。
【００３７】
図２に洩れ検査装置本体１００の内部構成を示す。洩れ検査装置本体１００は一般にコンピュータによって構成される。コンピュータはＣＰＵと呼ばれている中央演算処理装置１０１と、基本プログラムを格納したＲＯＭ１０２と、実動プログラム等を記録し、実行させるＲＡＭ１０３と、入力ポート１０４、出力ポート１０５等により構成される。
図２に示す実施例ではＲＡＭ１０３に外部の例えば磁気ディスク等から実動プログラムを読み込んで、これらの各実動プログラムをＲＡＭ１０３上で実行させる構成とした場合を示す。尚、実動プログラムをＲＯＭ１０２に焼き付けＲＯＭ１０２上で実行させる場合もある。
【００３８】
ＲＡＭ１０３にはドリフト補正手段３０を構成する手段としてドリフト値取得手段３０Ａと、ドリフト記憶器３０Ｂと、ドリフト書込読出手段３０Ｃとが設けられる。
更に、湿度補正手段５０を構成する手段としてシール誤差測定手段５０Ａと、シール誤差記憶器５０Ｂと、湿度補正係数取得手段５０Ｃと、湿度補正係数記憶器５０Ｄと、蒸気圧測定手段５０Ｅと、湿度補正値算出手段５０Ｆとが設けられる。また、減算手段６０と、判定手段７０とが設けられる。
【００３９】
入力ポート１０４には圧力センサ１６からの圧力測定値と、温度差測定器４からの被検査体Ｗとシール治具１との間の温度差の値が入力される。また出力ポート１０５には表示器２００が接続され、判定手段７０の判定結果を表示器２００に表示する。
ドリフト値取得手段３０Ａはプログラムによって構成される。このドリフト値取得手段３０Ａを構成するプログラムは校正モードにおいて選択されて起動される。ドリフト値取得手段３０Ａを構成するプログラムが起動されると、図４に示す手順に従って被検査体Ｗとシール治具１との間の温度差毎のドリフト値を取得する。
【００４０】
図４に示すステップＳ４１では洩れの無い乾燥された被検査体を用意し、シール治具１の上に載置する。
ステップＳ４２では被検査体Ｗに熱を加えて、シール治具１との温度差を所望の温度差に設定する。
ステップＳ４３では第２シール治具２（図１参照）で被検査体Ｗの開口部を閉塞し、電磁弁１７を開いて被検査体Ｗに空気圧を与える。
ステップＳ４４では測定期間Ｔ３（図５参照）で発生する圧力変化値Ｄをドリフト値として測定し、その測定結果をドリフト書込読出手段３０Ｃ（図１）によりドリフト記憶器３０Ｂに記憶する。尚、図５は被検査体Ｗに空気圧を印加するシーケンスを示す。Ｔ１は加圧期間、Ｔ２は平衡期間、Ｔ３は測定期間を示す。各期間は３〜５秒程度に設定される。
【００４１】
ステップＳ４５では所望の温度差の全てに渡ってドリフト値が取得されたか否かを判定する。所望の温度差の一部が未だに未取得である場合はステップＳ４２に戻り、ステップＳ４２〜Ｓ４４を再度実行する。全ての温度差に渡ってドリフト値が取得できた場合は終了する。図６にドリフト記憶器３０Ｂに取得したドリフト値の一例を示す。図６に横軸に示すように各記憶アドレスに温度差が割当られ、各温度差毎にドリフト値が記憶される。
次に湿度補正係数取得方法について説明する。湿度補正係数取得も校正モードで実行される。図７に湿度補正係数取得方法の手順を示す。
【００４２】
ステップＳ７１で洩れの無い常温乾燥被検査体を用意し、シール治具１の上に載置する。被検査体の温度が常温であることのよりシール治具１との温度差は０である。
ステップＳ７２では大気圧の環境下において第２シール治具２で被検査体の開口部を閉塞し、被検査体Ｗの内部に大気圧を封じ込める。
ステップＳ７３では所定の時間（例えば数秒程度）経過する間の被検査体の内部の圧力変化値ΔＰ_０を計測する。この圧力変化値は乾燥時の蒸気圧変化に該当し、これはシール治具２のシール誤差値（シール治具の形状変形等によって発生する誤差）にも該当する。以下ΔＰ_０をシール誤差値と称することにする。
【００４３】
ステップＳ７４では常温乾燥被検査体に空気圧を与え、乾燥状態におけるドリフト値ΔＰ_０１を計測する。
ステップＳ７５では同じ被検査体に対し、被検査体の内面に水滴を付着させて濡れ被検査体に変換し、この状態で被検査体の開口部を閉塞し、被検査体に大気圧を封じ込め、所定時間経過する間の蒸気圧変化値ΔＰ_１を計測する。
ステップＳ７６では被検査体に空気圧を印加し、測定期間Ｔ３（図５参照）で発生する圧力変化値ΔＰ_１１を計測する。
【００４４】
ステップＳ７７では湿度補正係数ｋを
ｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）
で算出し終了する。
尚、ステップＳ７７で演算したΔＰ_１−ΔＰ_０は濡れた被検査体の蒸気圧変化から、シール誤差値ΔＰ_０を差し引いた蒸気圧変化である。また、ΔＰ_１１−ΔＰ_０１は濡れた被検査体のドリフト値ΔＰ_１１から乾燥した被検査体のドリフト値ΔＰ_０１を差し引いた蒸気圧によるドリフト値である。
【００４５】
湿度補正係数ｋが算出されると、この湿度補正係数ｋは図２に示した湿度補正係数記憶器５０Ｄに記憶される。
以上により校正モードを終了することができる。上述した校正モードは被検査体（検査対象となる製品）が変更されない限りにおいてはしばしば行なう必要がなく、被検査体の品種が変換される毎に行なえばよい。但し、各製品毎に予め校正を行なって必要なデータを記憶してある場合は必ずしもその必要はない。
次に、検査モードについて説明する。検査モードでは第１シール治具１の上に被検査体Ｗを載置し、この被検査体Ｗの開口部も第２シール治具２で閉塞する。この閉塞状態で被検査体Ｗに大気圧を封じ込める。この閉塞状態で図２に示した蒸気圧測定手段５０Ｅにより測定する。任意の被検査体Ｗで測定された蒸気圧変化値がΔＰ_Ｘであるとき、湿度補正値算出手段５０Ｆは湿度補正値Ｍを、
Ｍ＝（ΔＰ_Ｘ−ΔＰ_０）ｋ
で算出する。
【００４６】
減算手段６０ではドリフト補正手段３０で各被検査体Ｗ毎に被検査体Ｗの温度とシール治具１との温度差から求めたドリフト値補正値Ｄ_０と湿度補正手段５０で求めた湿度補正値Ｍとを加算（Ｄ_０＋Ｍ）し、この加算結果を各検査毎に測定される圧力変化値Ｅから減算し、ドリフト補正と湿度補正された値Ｆを、
Ｆ＝Ｅ−（Ｄ_０＋Ｍ）
で求める。
判定手段７０はこのドリフト補正された値Ｆと洩れ判定のための判定値Ｙとを比較し、Ｆ＜Ｙであれば洩れ無し、Ｆ＞Ｙであれば洩れ有りと判定する。
【００４７】
図８に検査の様子を示す。ここでは検査に先だって各被検査体毎に蒸気圧変化値ΔＰ_Ｘを測定する蒸気圧変化値測定期間Ｔ０を設けた場合を示す。蒸気圧変化値測定期間Ｔ０で各被検査体毎に蒸気圧変化値ΔＰ_Ｘを測定する。測定後、加圧期間Ｔ１、平衡期間Ｔ２を経て測定期間Ｔ３に至る。測定期間Ｔ３で被検査体Ｗの内部の圧力変化値Ｅ（図８参照）を測定する。これと共に、ドリフト補正手段３０は被検査体Ｗとシール治具１との間の温度差に従ってドリフト記憶器３０Ｂからドリフト補正値Ｄ_０を読み出す。更に、湿度補正手段５０は湿度補正値Ｍを算出する。
【００４８】
減算手段６０は測定した圧力変化値Ｅからドリフト補正値Ｄ_０と湿度補正値Ｍとを加算した値（Ｄ_０＋Ｍ）を減算し、ドリフト補正と湿度補正が施されたドリフト補正された値Ｆを上述したようにＦ＝Ｅ−（Ｄ_０＋Ｍ）で求める。
被検査体Ｗに洩れが無ければＥ≒Ｄ_０＋Ｍとなり、この場合はＦ≒０となるからＦ＜Ｙとなり、洩れ無しと判定される。もし洩れが有る場合はＥ＞Ｄ_０＋Ｍとして測定されるから、Ｙ＜Ｅ−（Ｄ_０＋Ｍ）となる率が高くなり洩れ有りと判定される確率が高まる。
【００４９】
ところで、上述した実施例では図６に示したようにドリフト記憶器３０Ｂの各アドレスの全てに各温度差ごとのドリフト値を記憶した例を説明したが、このドリフト値を取得するには被検査体Ｗの温度を適当な温度に設定し、その温度によりシール治具１との温度差を設定してドリフト値を測定する方法を採るから、ドリフト値を取得するアドレスの数が大きい程その労力は大きい。
このために、ドリフト記憶器３０Ｂには数点のアドレスのみにドリフト値を記憶させ、他のアドレスのドリフト値は直線近似によって求める方法が考えられる。
【００５０】
図９はその実施例を示す。つまりこの実施例ではドリフト補正手段３０に図２に示した構成に加えて直線近似演算手段３０Ｄを設けた構成とした点を特徴とするものである。
この直線近似演算手段３０Ｄを設けたことにより、図１０に示すように例えば温度差として０℃と＋１５℃と＋３０℃の３点程度を設定し、これらの各温度差毎のドリフト値Ｄ１、Ｄ２、Ｄ３を記憶して用意すれば、他の温度のドリフト値は直線近似演算手段３０Ｄで算出することができる。また、算出する温度差として小数点以下も算出することができる構成とすれば、測定した温度差が例えば１３．５℃のように小数点を含む場合もその温度差に対応したドリフト値Ｄ_Ｍを求めることができる。
【００５１】
従って、図９に示した実施例によればドリフト補正のためのドリフト値を取得する労力を大きく低減することができる効果と、測定した温度差に対応したドリフト値を正確に求めることができる利点とが得られる。
図１１はこの発明の更に他の実施例を示す。この実施例では図９に示した洩れ検査装置本体１００にゼロ点変動値記憶器３０Ｅとゼロ点変動書込読出手段３０Ｆを設けた構成を特徴とするものである。このゼロ点変動値記憶器３０Ｅには例えば季節の変化などによりドリフト値Ｄが変動した量ΔＤをゼロ点変動値として記憶させる。このゼロ点変動値ΔＤが発生する理由としては、被検査体Ｗ及びシール治具１の平均温度（環境温度）が季節に応じて変動した場合、被検査体Ｗに封入した空気の温度変化（断熱変動）によるドリフト量が変動することが主因であると考えられている。このドリフト値Ｄが変動した量、ゼロ点変動値ΔＤを取得する方法を説明する。
【００５２】
ゼロ点変動値ΔＤを取得する方法は以下の２つの方法がある。
▲１▼ 洩れの無い被検査体Ｗを用意し、この被検査体Ｗと第１シール治具１との間の温度差をドリフト記憶器３０Ｂに存在する温度差Ｎ℃に設定する。この状態で加圧期間Ｔ１、平行期間Ｔ２を経て測定期間Ｔ３でドリフト値Ｇと、この時点における環境温度（シール治具の温度又は大気温度）を計測する。このドリフト値Ｇとドリフト記憶器１１ＦのＮ℃に対応するアドレスに記憶しているドリフト値Ｄとの偏差ΔＤ＝Ｇ−Ｄを求める。この偏差ΔＤがこの校正を行なった時点の環境温度下におけるゼロ点変動値である。
【００５３】
▲２▼ 被検査体Ｗと第１シール治具１との間の温度差を０℃に設定する。この場合被検査体Ｗは洩れの有無を問わない。洩れが有る被検査体（但しその洩れは大きい洩れではなくわずかな洩れであるものとする）を使ってドリフト値を測定できる理由は後に説明することとするが、ここでは手順のみを図１３を用いて簡素に説明する。加圧期間Ｔ１と、平衡期間Ｔ２を経て測定期間Ｔ３の終了時点で圧力計１６の圧力変化Ｄ１を測定する。その後、充分な時間（ドリフトが終息するまでの時間、数分程度）が経過した時点Ａから、先の測定期間Ｔ３と同じ時間Ｔ３が経過する間に変化する圧力変化値Ｄ２とＤ３を測定し、これらの差ΔＤ２＝Ｄ２−Ｄ３を求める。この差ΔＤ２が洩れによって発生する圧力変化値であるから、初回の測定値Ｄ１から、この差ΔＤ２を差し引くことにより、真のドリフト値Ｇを得ることができる。つまりＧ＝Ｄ１−ΔＤ２となる。このドリフト値Ｇがドリフト記憶器３０Ｂに温度差０℃のアドレスに記憶しているドリフト値Ｄとの間に偏差ΔＤ＝Ｇ−Ｄが存在すれば、その偏差ΔＤがその時点の環境温度下におけるゼロ点変動値である。偏差ΔＤは正か負かの極性を持つ（図１２参照）。
【００５４】
▲１▼、▲２▼の何れの方法でゼロ点変動値ΔＤを求めたとしても、このゼロ点変動値ΔＤをゼロ点変動値記憶器３０Ｅにゼロ点変動書込読出手段３０Ｆにより書き込んで記憶させればよい。検査モードではドリフト記憶器３０Ｂからドリフト書込読出手段３０Ｃにより読み出されるドリフト値Ｄにゼロ点書込読出手段３０Ｆにより読み出されるゼロ点変動値ΔＤを加算し、その加算結果を減算手段６０で検査中の被検査体Ｗで得られた圧力変化値Ｅ（図８）から減算し、その減算結果を判定手段７０に送り込む。また、湿度補正値Ｍも湿度補正手段５０で求められ、この湿度補正値Ｍも減算手段６０に送り込まれ湿度補正が施される。
検査モードでドリフト記憶器３０Ｂから読み出される全てのドリフト値Ｄにゼロ点変動値ΔＤを加算してドリフト補正することにより、図１２に示す本来の曲線Ａは補正曲線Ｂ又はＣに平行移動されて修正される。尚、図９に示した実施例と図１１に示した実施例は併合して実施することができることは容易に理解できよう。
【００５５】
図１４はこの発明の更に他の実施例を示す。この実施例では被検査体Ｗの開口部が１箇所の場合を示す。この場合には第２シール治具２と被検査体Ｗとの間の温度差を温度センサ３で測定し、その温度差を温度差測定器４で求めて洩れ検査装置本体１００に入力すればよい。従って、この場合も温度差測定器４で求めた温度差に従って、ドリフト記憶器３０Ｂからドリフト値Ｄを読み出し、このドリフト値Ｄを図２に示した実施例と同様に検査中の被検査体Ｗで測定した圧力変化値Ｅ（図４参照）から減算してドリフト補正を施す。また、この実施例にも図９及び図１１に示した実施例を併用することができる。また、湿度補正手段５０で湿度補正値Ｍを求め、この湿度補正値Ｍにより湿度補正を施す。
図１５はこの発明の更に他の実施例を示す。この実施例では温度センサ３を接触式の温度センサ３Ａ、３Ｂで構成した場合を示す。接触式の温度センサ３Ａ、３Ｂを用いることにより、被検査体Ｗ及び第２シール治具２に対する接触位置を任意に設定し、変更することができるから、温度差を測定するのに適した位置を自由に選択することができる利点が得られる。尚、被検査体Ｗに関して接触式の温度計で温度を測定できない品種もある。このような場合には非接触式の例えば赤外線放射温度計等を用いて被検査体Ｗの温度を測定することも考えられる。
【００５６】
図１６はこの発明を差圧検出型の洩れ検査装置に適用した場合を示す。差圧検出型洩れ検査装置はよく知られているように被検査体Ｗに対して洩れの無い基準タンクＭＳを設け、これら被検査体Ｗと基準タンクＭＳに電磁弁１７Ａ、１７Ｂを開閉して空気圧を封入する。空気圧の封入状態（電磁弁１７Ａ、１７Ｂを閉じた状態）において、基準タンクＭＳと被検査体Ｗとの間に設けた差圧計１６Ａにより基準タンクＭＳと被検査体Ｗとの間に圧力差が発生するか否かを測定する。差圧が発生した場合は、被検査体Ｗに洩れが有ると判定する型式の洩れ検査装置である。
【００５７】
この差圧検出型の洩れ検査の場合は被検査体Ｗに印加した空気圧と同じ空気圧が基準タンクＭＳに封じ込んでいるから、差圧計１６Ａは本来圧力差ゼロを検出するはずである。然し乍ら、図１及び図２に示した実施例と同様に、被検査体Ｗに封入した空気に圧力変化（ドリフト）が発生し、あたかも洩れが有るかの如き差圧が発生する。
この発明ではまず校正モードにおいて、洩れの無い常温乾燥被検査体Ｗを用意し、この被検査体Ｗに温度を与えて図１６に示す例では第２シール治具２との間に所望の温度差を与えた状態を設定する。この状態で加圧期間Ｔ１と、平衡期間Ｔ２を経て測定期間Ｔ３を実行し、各温度差毎にドリフト値を測定し、このドリフト値をドリフト記憶器３０Ｂの複数のアドレスにドリフト値Ｄを取得する。更に、図７で説明した手順に従って湿度補正係数ｋを求め、校正モードを終了し、その後検査を実施することができる。
【００５８】
検査モードでは図１７に示すように各検査の開始毎に被検査体Ｗ内の蒸気圧変化値ΔＰ_Ｘ（差圧式の洩れ検査装置では被検査体Ｗ内の圧力が上昇する蒸気圧変化は図１７に示すように負極性の差圧として検出される）を測定する。湿度補正手段５０は測定した蒸気圧変化値ΔＰ_Ｘと湿度補正係数ｋとにより湿度補正値Ｍを算出する。
加圧期間Ｔ１を経て検査モードにおいて、平衡期間Ｔ２で急激に差圧値が上昇した場合（図１７に示す直線Ｘ）には検査中の被検査体Ｗに「大きな洩れが有る」と判定する。判定期間Ｔ３の期間の終了時点で検査中の被検査体Ｗと基準タンクＭＳとの間に発生する差圧の値Ｅからドリフト記憶器３０Ｂから読み出したドリフト値Ｄ_０と先に求めた湿度補正値Ｍとの和を差し引いた値ＦをＦ＝Ｅ−（Ｄ_０＋Ｍ）で求める。ここで湿度補正値Ｍは蒸気圧変化値がΔＰ_Ｘで決めるため湿度補正値ＭはＭ＝（ΔＰ_Ｘ−ΔＰ_０）ｋで求める。従ってＦ＝Ｅ−（Ｄ_０＋Ｍ）で表記される。Ｅ−（Ｄ_０＋Ｍ）≒０であればほぼＦ≒０となる。この場合は「洩れ無し」と判定する。Ｆが判定値Ｙより大きい場合は「洩れ有り」と判定する。
【００５９】
図１６に示した実施例にも図９と図１１及び図１５に示した実施例を併用することができることは容易に理解できよう。
図１８はこの発明の更に他の実施例を示す。この実施例は図７に示した実施例の変形例である。つまり、図１１に示した実施例ではゼロ点変動値記憶器３０Ｅを設け、このゼロ点変動値記憶器３０Ｅに各季節毎にゼロ点変動値を記憶させ、このゼロ点変動値によりドリフト記憶器３０Ｂから読み出されるドリフト値を補正し、環境温度の変化に伴うドリフト値の変動を修正する構成を付加した実施例を説明した。この図１１に示した実施例によれば各季節毎にゼロ点変動値を取得するための校正モードを実行しなければならない不都合が生じる。
【００６０】
図１８に示す実施例はこの不都合を解消することができる洩れ検査装置を提案するものである。
このために図１１に示したゼロ点変動値記憶器３０Ｅを複数の環境温度のゼロ点変動値を記憶することができるゼロ点変動値記憶器３０Ｅ´に変更するものとし、更に環境温度測定手段５を設けた構成を特徴とするものである。
図１８に示す環境温度測定手段５は例えば温度センサ３において第１シール治具１の温度を測定した温度測定値を環境温度として流用するように構成することができる。
【００６１】
図１１で説明したゼロ点変動値取得方法▲１▼又は▲２▼の何れかにより、ゼロ点変動値を求め、その時点の環境温度をゼロ点変動値記憶器３０Ｅ´のアドレスに対応させて記憶させる。図１９に環境温度Ｔ_Ｓに対するゼロ点変動値ΔＤの傾向を示す。図１９に環境温度Ｔ_Ｓが上昇するに伴ってゼロ点変動値ΔＤが漸次小さくなる傾向を呈する場合を示す。
洩れ検査装置が製造され、利用者に引き渡された時点ではドリフト記憶器３０Ｂ（図２参照）及びゼロ点変動値記憶器３０Ｅ´にはデータが全く書き込まれていない。ドリフト記憶器３０Ｂにはこの発明で提案したドリフト値取得方法によりドリフト値を取り込む。これと共に、ゼロ点変動値記憶器３０Ｅ´にも、その時点の環境温度のゼロ点変動値を書き込むことができる。従って、運用開始時点ではゼロ点変動値記憶器３０Ｅには１個のゼロ点変動値のみが書き込まれた状態にある。このゼロ点変動値はその季節（環境温度下）では有効に利用することができる。
【００６２】
季節が終わり、環境温度が変わる毎にゼロ点変動値を取得し、ゼロ点変動値記憶器３０Ｅ´に書き込むことを年間を通じて実行することにより、図１９に示すほぼ全体のアドレスにゼロ点変動値を取り込むことができる。ゼロ点変動値を取り込みができないアドレス（環境温度）が存在しても、そのアドレスのゼロ点変動値は直線近似演算手段３０Ｄで直線近似により求めることができる。従って、この実施例では直線近似演算手段３０Ｄはドリフト記憶器３０Ｂから読み出すべきドリフト値が存在しない場合と、ゼロ点変動値記憶器３０Ｅ´から読み出すべきゼロ点変動値が存在しない場合の双方の直線近似を実行する手段として動作する。
【００６３】
年間を通じてゼロ点変動値を測定し、その測定結果をゼロ点変動記憶器３０Ｅ´に書き込むことにより、その後は環境温度に対応したゼロ点変動値をゼロ点変動値記憶器３０Ｅ´から直接又は直線近似演算手段３０Ｄから得ることができる。
従って、このゼロ点変動値を利用してドリフト記憶器３０Ｂから読み出されるドリフト値を修正し、その修正されたドリフト値を検査中の被検査体Ｗで発生する圧力変化値Ｅ（図８及び図１７参照）から差し引くことにより、四季を通じて正しくドリフト値を除去することができる。従って、ゼロ点変動値記憶器３０Ｅ´に複数の環境温度に渡ってゼロ点変動値を取り込むことができた時点からは校正モードを全く実行せずに全自動で洩れ検査を行なうことができる利点が得られる。
【００６４】
図２０は図１８に示した実施例を差圧式の洩れ検査装置に適用した場合を示す。差圧式の洩れ検査装置の場合でも、洩れ検査装置本体１００に各環境温度毎にゼロ点変動値を記憶することができるゼロ点変動値記憶器３０Ｅ´を設ける点と環境温度測定手段５が設けられる。この実施例では、第２シール治具２の温度を環境温度として洩れ検査装置本体１００に取り込む構成とした場合を示す。
差圧式の洩れ検査装置の場合でも、まず洩れの無い被検査体を使ってドリフト記憶器３０Ｂ（図２参照）に被検査体とシール治具間の温度差毎のドリフト値を用意すると共に、図１１及び図１２で説明したゼロ点変動値取得方法▲１▼又は▲２▼によりゼロ点変動値を求め、その時点の環境温度に対応したゼロ点変動記憶器３０Ｅ´のアドレスにその求めたゼロ点変動値を記憶させる。このゼロ点変動値の取得を各環境温度毎に実行して、ゼロ点変動値記憶器３０Ｅ´の複数のアドレスにゼロ点変動値を取り込むと共に、湿度補正値算出手段５０において湿度補正係数ｋを求めておくことにより、その後は全自動で洩れ検査を行なうことができる。
【００６５】
ところで、上述の実施例では湿度補正値Ｍを求めるために被検査体Ｗの内部の蒸気圧変化を測定したが、この方法を採った場合は検査の開始前の時点で被検査体Ｗの内部の蒸気圧変化を測定しなければならない。
このために、検査に要する時間が蒸気圧変化の測定時間Ｔ０（図８又は図１７参照）分だけ長くなる。この時間の延長は被検査体Ｗの個数が多くなる程総計として長くなり、高価な検査装置を長い時間専用することになり、検査コストが高価になる欠点がある。
【００６６】
このため、この発明では更に被検査体Ｗの外部の面を代用して被検査体Ｗの濡れの状態を検出する洩れ検査装置を提案する。
図２１はその実施例を示す。この実施例では被検査体Ｗの外側面（平面）に計測治具８０をシール部材ＣＣを介して接触させ、この計測治具８０の凹部８１によって被検査体Ｗの外側面に密閉された空間８２を形成し、この空間８２の圧力変化と蒸気圧測定用圧力センサ８３で測定して空間８２の蒸気圧変化を計測する構成としたものである。
【００６７】
この構成を採る場合、校正モードでは、
▲１▼ シール誤差は洩れの無い乾燥された常温の被検査体Ｗの外壁に計測治具８０を圧接し、圧接状態が安定した状態（圧接時点から数秒程度経過した時点）で電磁弁８４を開いて空間８２の内部を大気圧にリセットし、再び電磁弁８４を閉じる。電磁弁８４を閉じた時点から更に数秒程度経過した時点の圧力変化を蒸気圧測定用圧力センサ８３で計測し、この計測値をシール誤差ΔＰ_０とする。
▲２▼ 次に、同じ被検査体Ｗに空気圧を印加し、被検査体Ｗ内の圧力変化値を図２１の例では差圧計１６Ａで測定する。その差圧値を乾燥された常温被検査体における被検査体Ｗとシール治具１との間の温度差０℃の状態のドリフト値ΔＰ_０１として取得する。
【００６８】
▲３▼ 同じ被検査体Ｗを用いて、被検査体Ｗの内側と外側に均等に水滴を付着させ、濡れ被検査体に変換する。（ワーク全体を濡らし、しばらく放置させた状態では内外とも均等に塗れた状態になる。）
▲４▼ 水滴が付着した被検査体の外面に計測治具８０を被せ、シール誤差ΔＰ_０の測定時と同様に電磁弁８４を開いて空間８２を大気圧にリセット後、電磁弁８４を閉じて、数秒後の圧力変化値を蒸気圧測定用圧力センサ８３で計測する。この値をΔＰ_１とし、濡れた被検査体の蒸気圧変化値とする。
【００６９】
▲５▼ 同じ被検査体Ｗでシール治具２で開口部を閉塞し、被検査体Ｗの内部に空気圧を印加し、所定の時間が経過する間の圧力変化値をこの例では差圧計１６Ａで計測し、この値を濡れ被検査体のドリフト値ΔＰ_１１として取得する。
▲６▼ これらの測定結果から、湿度補正係数ｋを
ｋ＝（ΔＰ_１１−ΔＰ_０１）／（ΔＰ_１−ΔＰ_０）
で求め、この湿度補正係数ｋとシール誤差値ΔＰ_０を湿度補正手段５０に格納する。
以上により図２１に示した実施例における校正モードが終了する。
【００７０】
検査モードでは
▲１▼ 被検査体Ｗの外壁に計測治具８０を装着し、被検査体Ｗの外壁の濡れによる蒸気圧変化ΔＰ_Ｘを計測する。
▲２▼ この蒸気圧変化ΔＰ_Ｘからシール誤差ΔＰ_０を減算した値に湿度補正係数ｋを乗算し、湿度補正値Ｍを求める。
Ｍ＝（ΔＰ_Ｘ−ΔＰ_０）ｋ
▲３▼ 被検査体Ｗの内部の圧力変化Ｅ（ドリフト値）を計測し、この圧力変化Ｅから被検査体Ｗとシール治具２との間の温度差に従って読み取ったドリフト補正値Ｄ_０（ドリフト補正手段３０に格納されている）と湿度補正値Ｍを減算し、ドリフト補正と湿度補正が施された値Ｆを求める。
Ｆ＝Ｅ−（Ｄ_０＋Ｍ）
▲４▼ Ｆと判定値Ｙとを比較し、Ｙ＞Ｆならば洩れ無し、Ｙ＜Ｆならば洩れ有り、と判定し検査を終了する。
このように、被検査体Ｗの外側で被検査体Ｗの濡れの状態を計測しても、内部と外部とでは濡れの状態に関して相関性を持つと考えられるため、被検査体Ｗの内部を用いて校正した場合と同様に、湿度補正が施された洩れ検査を行なうことができる。
【００７１】
ここで特に検査モードで各被検査体毎に行なう蒸気圧測定は図２２Ａに示すように、被検査体Ｗの内部の圧力変化を計測するための加圧期間Ｔ１と、平衡期間Ｔ２と、測定期間Ｔ３を実行している間の任意の時間に実行すればよく、従来の検査に要した時間と同じ時間で湿度補正を施した洩れ検査を行なうことができる点が大きな特徴である。
ところで、蒸気圧変化を測定する際に計測冶具８０の内部を大気圧で測定した場合、蒸気圧変化を精度よく測定するには測定時間Ｔ_０（図８又は図１７参照）を比較的長く採らなければならない不都合が生じる。これに対し、計測冶具８０の内部を負圧にした状態で蒸気圧変化を測定すると短時間に精度よく蒸気圧変化を測定できることが判明した。その理由としては、計測冶具８０の内部を負圧にすることにより、水分の蒸発が促され、短時間に水分の蒸発による圧力変化が大幅に発生するためと考えられる。
【００７２】
図２３に計測冶具８０の内部を負圧にして蒸気圧を測定し、被検査体Ｗに付着している水分の量を計測する場合の実施例を示す。
この実施例では電磁弁８４の開放端部に負圧発生器（真空ポンプ）８５を接続し、電磁弁８４の一端側に負圧を印加する。蒸気圧を測定する際には、計測冶具８０を被検査体Ｗの外壁に付着させた後、電磁弁８４を開に制御し、蒸気圧測定用圧力センサ８３で所定の負圧に達したことを検出し、その負圧で電磁弁８４を閉じ、その時点から所定の時間が経過する間の計測冶具８０の内部の圧力変化を蒸気圧変化値ΔＰ_１として計測する。
校正モードでこの蒸気圧変化値ΔＰ_１を測定した後の処理は上述と同じであるが、この場合、特にシール誤差ΔＰ_０を測定し、記憶しておく必要がない利点が得られる。つまり、計測冶具８０の内部の空気を負圧に吸引してしまうため、計測冶具８０の内部の圧力がシール部材ＣＣの変形等によって変動する現象が発生しないためである。
従って、校正モードで求める湿度補正係数ｋは
ｋ＝（ΔＰ_１１−ΔＰ_０１）／ΔＰ_１
で求められる。
更に検査モードでは、検査モードで測定した蒸気圧変化値がΔＰ_ｘであるものとすると、検査モードで求める湿度補正値Ｍは、
Ｍ＝ΔＰ_ｘ・ｋ
で求められる。
従って、計測冶具８０の内部を負圧にして蒸気圧を測定して湿度補正を行う場合には、蒸気圧変化を短時間に精度よく測定できる利点に加えてシール誤差ΔＰ_０の測定を行わなくて済む利点が得られる。
【００７３】
【発明の効果】
以上説明したように、この発明によればドリフト補正値は乾燥された被検査体を用いて取得し、湿度補正値Ｍは濡れた被検査体を用いて求めた湿度補正係数ｋにより算出したから、ドリフト補正から湿度の影響を除去することができる。また、湿度補正には乾燥時のドリフト補正の影響を除去することができる。
この結果、乾燥状態のドリフトと、濡れた被検査体で発生する湿度によるドリフトとをほぼ完全に除去することができ、信頼性の高い洩れ検査を行なうことができる。
【００７４】
また、複数の環境温度で発生するゼロ点変動値をそれぞれゼロ点変動値記憶器３０Ｅ´に記憶させる構成とした場合には、複数の環境温度にゼロ点変動値を記憶した時点以後は、どの環境温度に変化しても、その時点の環境温度のゼロ点ドリフト値を得ることができるから、四季を通じて全自動で洩れ検査装置駆動させることができる。この結果、定期的に校正モードを実行しなくてすむから、洩れ検査装置の実動率を向上させることができ、検査コストの低減も期待することができる利点も得られる。
更に、図２１及び図２３に示した実施例によれば湿度補正を施しても検査に要する時間が長くなることがないから、多量の被検査体を検査する場合に好適である。また、図２３に示した実施例によれば、蒸気圧を短時間に精度よく測定できる利点に加えてシール誤差ΔＰ_０を測定し、記憶しなくて済むため、装置を簡素化できる利点も得られる。
【図面の簡単な説明】
【図１】この発明による洩れ検査装置の一実施例を説明するためのブロック図。
【図２】図１に示した洩れ検査装置の要部の構成を説明するためのブロック図。
【図３】図１に示した洩れ検査装置に用いる温度センサの構造の一例を説明するための断面図。
【図４】この発明のドリフト値取得方法の手順を説明するためのフローチャート。
【図５】図１に示した洩れ検査装置の動作を説明するためのグラフ。
【図６】図２に示したドリフト記憶器に記憶したドリフト値の一例を説明するためのグラフ。
【図７】この発明の湿度補正係数取得方法の手順を説明するためのフローチャート。
【図８】図１及び図２に示した洩れ検査装置の検査モードの動作を説明するためのグラフ。
【図９】この発明の変形実施例を説明するためのブロック図。
【図１０】図９に示した変形実施例の動作を説明するためのグラフ。
【図１１】この発明の更に他の変形実施例を説明するためのブロック図。
【図１２】図１１に示した変形実施例の要部の動作を説明するためのグラフ。
【図１３】図１１に示した実施例で用いるゼロ点変動値取得方法を説明するためのグラフ。
【図１４】この発明の更に他の変形実施例を説明するためのブロック図。
【図１５】この発明の更に他の実施例を説明するためのブロック図。
【図１６】この発明の更に他の実施例を説明するためのブロック図。
【図１７】図１６に示した実施例の動作を説明するためのグラフ。
【図１８】図１６に示した実施例の他の実施例を説明するためのブロック図。
【図１９】図１８に示した実施例の動作を説明するためのグラフ。
【図２０】図１６に示した実施例の他の実施例を説明するためのブロック図。
【図２１】この発明の更に他の実施例を説明するためのブロック図。
【図２２】図２１に示した実施例の動作を説明するためのグラフ。
【図２３】図２１に示した実施例の他の実施例を説明するためのブロック図。
【図２４】温度と飽和蒸気圧の関係を説明するための図。
【符号の説明】
１第１シール治具３０Ｆゼロ点変動書込読出手段
２第２シール治具５０湿度補正手段
３温度センサ５０Ａシール誤差測定手段
４温度差測定器５０Ｂシール誤差記憶器
５環境温度測定手段５０Ｃ湿度補正係数取得手段
１４中子５０Ｄ湿度補正係数記憶器
１５配管５０Ｅ蒸気圧測定手段
１６圧力センサ５０Ｆ湿度補正値算出手段
１６Ａ差圧計６０減算手段
１７、１７Ａ、１７Ｂ電磁弁７０判定手段
１８３方電磁弁８０計測冶具
１９調圧弁８５負圧発生器
２０空圧源１００洩れ検査装置本体
３０ドリフト補正手段１０１中央演算処理装置
３０Ａドリフト値取得手段１０２ＲＯＭ
３０Ｂドリフト記憶器１０３ＲＡＭ
３０Ｃドリフト書込読出手段１０４入力ポート
３０Ｄ直線近似演算手段１０５出力ポート
３０Ｅ、３０Ｅ´ ゼロ点変動値記憶器２００表示器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a leak inspection device for inspecting the presence of leaks in various containers, engine cylinder blocks, gas appliances, and other devices that should not have leaks. An object of the present invention is to propose a method and an apparatus for calibrating a leak inspection apparatus capable of determining the presence or absence.
[0002]
[Prior art]
The leak inspection apparatus seals pressurized air in an object to be inspected, and measures a change in the air pressure to inspect for leakage. However, air is affected by the temperature of the test object or the temperature of a jig or the like that comes into contact with the test object, and causes pressure fluctuation (which is referred to as drift) that causes leakage without leakage. And it is difficult to determine the presence or absence of leakage.
For this reason, the present applicant has conventionally made various proposals regarding various leak inspection methods and drift correction of the leak inspection apparatus.
[0003]
The drift correction method proposed in the past considers the cause of drift to be the main cause of the temperature change of the pressurized gas applied to the test object (adiabatic change at the time of pressurization application). A method of deriving a drift correction coefficient from a pressure change has been adopted (for example, Patent Document 1).
According to the drift correction method proposed in Patent Document 1, in the calibration mode, drift correction works properly only within the range of the condition for which the drift correction coefficient is obtained. Is not performed.
[0004]
In order to solve this situation, the present applicant pays attention to the temperature difference between the seal jig that closes the opening of the pair to be inspected and the object to be inspected, identifies the temperature difference as a cause of the drift, and determines this temperature in the calibration mode. A drift correction method for obtaining a drift correction value for each difference and storing it as a table, measuring a temperature difference between the sealing jig and the test object in the inspection mode, reading the drift correction value from the table according to the temperature difference, and correcting the drift correction value ( Patent Documents 2 and 3) have been proposed.
[0005]
[Patent Document 1]
JP 2001-50854 A
[Patent Document 2]
JP 2002-22592 A
[Patent Document 3]
JP 2003-106923 A
[0006]
[Problems to be solved by the invention]
According to various drift correction methods proposed in the past by the present applicant, if the object to be inspected is completely dry, drift correction can be performed almost completely correctly. However, it has been found that when the object to be inspected is in a wet state (a state in which even a small amount of water droplets are attached), a situation occurs in which a judgment is erroneously made.
For example, in the case of an engine block, when processing is completed, cleaning is performed with cleaning water, and the cleaning process is passed to an inspection process. Although a drying process is provided at the end of the cleaning process, it is difficult to perform complete drying in a short time.Therefore, in many cases, a leak test is performed in a situation where slight water droplets adhere to the inner wall of the engine block. Exists.
[0007]
The liquid droplets always evaporate toward the saturated vapor pressure at the temperature of the test object. In other words, if water droplets adhere to the test object, even if the temperature of the test object is room temperature and the opening is closed with a sealing jig, the water droplets evaporate toward the saturated vapor pressure at the test object temperature. Continue. As a result, when water droplets are present, the pressure inside the test object continues to increase, albeit slightly, and the pressure rise due to evaporation causes erroneous determination of "no leakage" despite slight leakage. May fall.
[0008]
FIG. 24 shows the correspondence between the temperature and the saturated vapor pressure (extracted from the scientific chronological table). As is apparent from this figure, there is a difference of about four times in the saturated vapor pressure between the case where the temperature is 10 ° C. and the case where the temperature is 30 ° C. Therefore, the higher the temperature of the test object, the greater the effect of water droplets. I understand.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a drift inspection apparatus capable of correctly performing drift correction even when there is a temperature difference between an inspection object and a sealing jig, and even when water droplets adhere to the inspection object. A method for obtaining a value, a method for obtaining a temperature correction coefficient, a method for obtaining a zero-point variation value, a method for calibrating a leak inspection device, and a leak inspection device calibrated and operated by the calibration method are proposed.
[0009]
[Means for Solving the Problems]
According to the present invention, in the drift value acquisition method proposed in the prior application (Patent Document 3), the specimen to be used for acquiring the drift value in the calibration mode is specified as a dried specimen without leakage, and the specimen is dried. A drift value is acquired for each temperature difference between the seal jig and the test object using a certain test object, and drift correction is performed as before using the drift value in the test mode.
At the same time, in the present invention, in the calibration mode, a water droplet is attached to the test object in a dry state, converted into a wet test object, and the vapor pressure generated from the water droplet is measured using the wet test object, and the vapor pressure is measured. A humidity correction coefficient k is obtained by using the pressure, and in the inspection mode, the vapor pressure is measured for each of the test objects, and the vapor pressure is normalized by the humidity correction coefficient k to obtain a humidity correction value M. It is characterized in that the humidity correction is performed by subtracting M from the drift value that has been previously drift corrected.
[0010]
Therefore, according to the present invention, it is possible to correct both the drift caused by the temperature difference between the sealing jig and the test object and the drift caused by the vapor pressure generated from the water droplet, thereby providing a highly reliable leak. An inspection device can be provided.
The specific solution is as follows.
In the present invention, the opening of the test object is closed by a sealing jig, air pressure is sealed inside the test object in the closed state, and a change in the air pressure is measured. In a leakage inspection device that determines that there is no leakage when the amount of decrease in
In the calibration mode, a room temperature dried test object that has been dried without leakage to the test object is prepared, and a predetermined temperature difference is set between the normal temperature dried test object and the sealing jig. Applying air pressure to the room-temperature dried test object in the state where the temperature difference is given, and measuring the amount of change in the air pressure as a drift value for each of the plurality of temperature differences, and calculating the drift values of the plurality of temperature differences. Is proposed to obtain a drift value of a leakage inspection device in which a drift value is stored in a drift storage device.
[0011]
According to the present invention, the opening of the test object is further closed by a sealing jig, and in this closed state, the air pressure is sealed in the test object and the reference tank, and leaks into the test object depending on whether a pressure difference is generated between the two. In the leak inspection device that determines whether there is
In the calibration mode, a room temperature dried test object that has been dried without leakage to the test object is prepared, and a predetermined temperature difference is set between the normal temperature dried test object and the sealing jig. In a state where the temperature difference is given, the room temperature is dried and the air is sealed between the test object and the reference tank, and the amount of change in the pressure difference is measured as a drift value for each of the plurality of temperature differences. A drift value acquisition method for a leakage inspection device, wherein a drift value is stored in a drift storage device is proposed.
[0012]
According to the present invention, there is further provided a leak inspection apparatus in which a drift value corresponding to a temperature difference between an object to be inspected and a seal jig is stored in a drift storage device by any one of drift acquisition methods of the leak inspection apparatus.
In the calibration mode, prepare a room temperature dried test object that has been dried without leakage, measure the temperature difference between the room temperature dried test object and the sealing jig, and store the drift value corresponding to this temperature difference in the drift The drift value and the environmental temperature are measured by applying air pressure to the room-temperature dried test object, and the deviation between the drift value obtained by this measurement and the drift value derived from the drift storage device is obtained, We propose a method for obtaining a zero-point variation value of a leakage inspection apparatus that stores the deviation value in a zero-point variation storage unit as a zero-point variation value corresponding to the measured environmental temperature.
[0013]
According to the present invention, there is further provided a leak inspection apparatus in which a drift value corresponding to a temperature difference between an object to be inspected and a seal jig is stored in a drift storage device by any of drift value obtaining methods of the leak inspection apparatus.
In the calibration mode, prepare a dried room temperature dried test object whose leakage is unknown or not, and reduce the temperature difference between the dry room temperature dried test object whose leakage is unknown and the sealing jig to zero. In this state, air pressure is applied to the test object to measure the provisional drift value and the environmental temperature, and the pressure change due to leakage alone is measured at a time longer than the drift measurement timing. The true drift value is obtained by subtracting the pressure change from the temporary drift value, and the deviation between the obtained drift value and the drift value stored at the address corresponding to zero temperature difference in the drift storage device is obtained. We propose a method for obtaining a zero-point fluctuation value of a leakage inspection device that stores a value in a zero-point fluctuation memory as a zero-point fluctuation value corresponding to the measured environmental temperature.
[0014]
According to the present invention, in any of the zero point fluctuation value acquisition methods of the leakage inspection device,
Zero point fluctuation value acquisition method that acquires zero point fluctuation values obtained by the zero point fluctuation value acquisition method for each of a plurality of environmental temperatures and stores the zero point fluctuation values acquired for each environmental temperature in a zero point fluctuation value storage Suggest.
In the present invention, the opening of the test object is further closed by a sealing jig, air pressure is applied to the inside of the test object in this closed state, and the amount of change in the air pressure inside the test object after a predetermined time has elapsed is measured. Then, when the amount of decrease in air pressure is large, there is leakage, and when the amount of decrease in air pressure is small, it is determined that there is no leakage.
In the calibration mode, prepare a room-temperature-dried test object without leakage, close the opening of the room-temperature-dried test object with a sealing jig, and change the pressure inside the test object after a predetermined time elapses in the closed state. The value is the seal error value ΔP₀And applying the air pressure to the room temperature dried test object, and calculating the pressure change value during a predetermined time after the application of the air pressure as a drift value ΔP₀₁The process of measuring the temperature of the sample, the process of attaching the water droplets to the inner surface of the room temperature dried test object to convert the room temperature dried test object to the room temperature wet test object, and closing the opening of the room temperature wet test object with a sealing jig. Then, the pressure change value during the elapse of the predetermined time is determined by the evaporative air pressure ΔP₁And applying air pressure to the room temperature wet test object, and calculating a change in air pressure during a predetermined time after the application of the air pressure to the drift value ΔP of the wet test object.₁₁And the humidity correction coefficient k is k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀) And the seal error value ΔP₀And a method of obtaining a humidity correction coefficient of the leak inspection apparatus, which executes the process of storing the humidity correction coefficient k in the storage device.
[0015]
According to the present invention, the opening of the test object is further closed by a sealing jig. In this closed state, air pressure is applied to the test object and the reference tank, and the test object is determined based on whether a pressure difference is generated between the two. In the correction coefficient acquisition method of the wetness inspection device to determine whether there is a leak,
In the calibration mode, prepare a room-temperature-dried test object without leakage, close the opening of the room-temperature-dried test object with a sealing jig, and after a predetermined time elapses in the closed state, the room-temperature-dried test object and the reference tank. The differential pressure value generated between the seal jig and the seal error value ΔP₀And applying the air pressure to the room temperature dried test object and the reference tank, and calculating the differential pressure value generated during a predetermined time after the application of the air pressure as a drift value ΔP₀₁A process of converting the room temperature dried test object into a room temperature wet test object by attaching a water droplet to an inner surface of the room temperature dry test object, and a process of sealing the opening of the room temperature wet test object with the sealing jig. And the change value of the differential pressure during the elapse of a predetermined time is determined by the evaporative air pressure ΔP₁And applying a pneumatic pressure to the room temperature wet test object and the reference tank, and calculating a change value of the differential pressure during a predetermined time after the application of the air pressure, the drift value ΔP of the wet test object.₁₁And the humidity correction coefficient k is k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀) And the seal error value ΔP₀And a method of obtaining a humidity correction coefficient of the leak inspection apparatus, which executes the process of storing the humidity correction coefficient k in the storage device.
[0016]
In the present invention, the sealing error value ΔP₀And the humidity correction method of the leak inspection device storing the humidity correction coefficient k,
In the inspection mode, the opening of the test object is closed with a sealing jig, and in this closed state, the pressure change value inside the test object or the differential pressure value generated between the test object and the reference tank is ΔP_XWhen the humidity correction value M is measured as M = (ΔP_X−ΔP₀) K, the humidity correction value M is removed from the drift value generated at the time of the leak test, and a humidity correction method of a leak test apparatus for correcting the humidity is proposed.
[0017]
According to the present invention, a drift value corresponding to a temperature difference between an object to be inspected and a sealing jig is stored in a drift storage device by a drift value acquiring method of the leak inspection device, and a humidity correction coefficient of the leak inspection device according to claim 6. Depending on the acquisition method, seal error value ΔP₀3. A drift corresponding to a temperature difference between an object to be inspected and a sealing jig in a drift memory by a leak inspection method of a leak inspection device storing a humidity correction coefficient k and a drift value acquisition method of the leak inspection device according to claim 2. And a seal error value ΔP obtained by the method for obtaining a humidity correction coefficient of the leak inspection apparatus according to claim 7.₀In any one of the leak inspection methods of the leak inspection apparatus storing the humidity correction coefficient k and the humidity correction coefficient k,
In the inspection mode, the temperature difference between the test object and the sealing jig is measured, the drift correction value corresponding to the temperature difference is read out from the drift memory, and this drift value is changed by the change in the air pressure sealed in the test object. In addition to removing the drift component generated during the leak test, the opening of the test object is sealed with a sealing jig under an atmospheric pressure environment, and the pressure from the sealed state until a predetermined time has elapsed from the sealed state. Change value ΔP_XAnd the pressure change value ΔP_XFrom the seal error value ΔP₀(ΔP_X−ΔP₀) Is multiplied by a humidity correction coefficient k to obtain a humidity correction value M in the inspection mode as M = (ΔP_X−ΔP₀) K, subtract the humidity correction value M from the amount of change in air pressure from which the drift component has been removed, and compare the subtraction result with a judgment value for judging the presence or absence of leakage.
[0018]
According to the present invention, a seal jig for closing the opening of the test object, a temperature sensor for measuring a temperature difference between the seal jig and the test object, and a change in air pressure inside the test object are measured. Drift value acquisition for acquiring as a drift value the pressure change generated inside the room temperature dried test object for each temperature difference between the pressure sensor to be tested and the room temperature dried test object having no leakage in the calibration mode and the sealing jig. Means, a drift storage device for storing a drift value for each temperature difference obtained by the drift value obtaining means, and a sealing jig for opening an opening of a room-temperature wetted test object having no leakage in a calibration mode under an atmospheric pressure environment. The seal error value ΔP is obtained from the pressure change measured by the pressure sensor in the closed state.₀And a seal error value ΔP measured by the seal error measuring means.₀And a seal error storage device for storing the opening of the room temperature wet test object in the calibration mode without leakage with a seal jig under an atmospheric pressure environment, and a pressure change value measured by a pressure sensor in the closed state. ΔP₁And a pressure change value ΔP inside the room-temperature dried test object generated during a predetermined time period by applying air pressure to the room-temperature dried test object.₀₁And a pressure change value ΔP inside the normal temperature wet inspection object generated during the lapse of a predetermined time by applying air pressure to the normal temperature wet inspection object.₁₁Are measured, and these measurement results and the seal error value ΔP₀And the humidity correction coefficient k is given by k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀), A humidity correction coefficient storage unit that stores the humidity correction coefficient k obtained by the humidity correction coefficient obtaining unit, a test object and a seal jig measured by a temperature sensor in the inspection mode. A drift writing / reading means for reading a drift value corresponding to a temperature difference from the drift storage from the drift storage unit, and in an inspection mode, an opening of the object to be inspected is closed by a sealing jig under an atmospheric pressure environment. Pressure measurement means for measuring the pressure change inside the test object at the time of humidity correction, and the measured value ΔP measured by the steam pressure measurement means_XFrom the seal error value ΔP₀Is subtracted, and the subtracted value (ΔP_X−ΔP₀) Is multiplied by a humidity correction coefficient k to obtain a humidity correction value M, and a drift value and humidity read by the drift writing / reading means from the change in air pressure enclosed in the test object in the inspection mode. A subtraction unit that subtracts the correction value M to perform drift correction and humidity correction, and a determination unit that compares the result subtracted by the subtraction unit with a set value to determine whether or not the inspection object has leaked. We propose a leak inspection device.
[0019]
According to the present invention, a seal jig for closing the opening of the test object, a temperature sensor for measuring a temperature difference between the seal jig and the test object, and a temperature sensor generated between the test object and the reference tank are provided. A differential pressure sensor that measures a change in differential pressure that occurs between the room-temperature-dried test object and the reference tank for each temperature difference between the room-temperature-dried test object and the sealing jig that does not leak in the calibration mode. Drift value acquiring means for acquiring a differential pressure change as a drift value, a drift memory for storing a drift value for each temperature difference acquired by the drift value acquiring means, and a room-temperature dried test object having no leakage in a calibration mode. The opening is closed with a sealing jig under an atmospheric pressure environment, and the sealing error value ΔP is obtained from a change in the differential pressure measured by the differential pressure sensor in the closed state.₀And a seal error value ΔP measured by the seal error measuring means.₀And a seal error memory for storing the opening of the room temperature wet test object in the calibration mode, which is leak-free, is closed with a seal jig under an atmospheric pressure environment, and the differential pressure measured by the differential pressure sensor in the closed state. Change value ΔP₁And an air pressure is applied to the room-temperature dried test object and the reference tank, and a differential pressure change value ΔP between the room-temperature dry test object and the reference tank generated during a predetermined time has elapsed.₀₁The air pressure is applied to the normal temperature wet test object, and the differential pressure change value ΔP between the normal temperature wet test object and the reference tank during a predetermined time elapses.₁₁Are measured, and these measurement results and the seal error value ΔP₀And the humidity correction coefficient k is given by k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀), A humidity correction coefficient storage unit that stores the humidity correction coefficient k obtained by the humidity correction coefficient obtaining unit, a test object and a seal jig measured by a temperature sensor in the inspection mode. A drift writing / reading means for reading a drift value corresponding to a temperature difference from the drift storage from the drift storage unit, and in an inspection mode, an opening of the object to be inspected is closed by a sealing jig under an atmospheric pressure environment. Pressure measurement means for measuring the pressure change inside the test object at the time of humidity correction, and the measured value ΔP measured by the steam pressure measurement means_XFrom the seal error value ΔP₀Is subtracted, and the subtracted value (ΔP_X−ΔP₀) Is multiplied by a humidity correction coefficient k to obtain a humidity correction value M, and a drift value and humidity read by the drift writing / reading means from the change in air pressure enclosed in the test object in the inspection mode. A subtraction unit that subtracts the correction value M to perform drift correction and humidity correction, and a determination unit that compares the result subtracted by the subtraction unit with a set value to determine whether or not the inspection object has leaked. We propose a leak inspection device.
[0020]
In the present invention, the opening of the test object is further closed by a sealing jig, air pressure is applied to the inside of the test object in this closed state, and the amount of change in the air pressure inside the test object after a predetermined time has elapsed. Measure and determine that there is leakage when the amount of decrease in air pressure is large, and that there is no leakage when the amount of decrease in air pressure is small.Close the opening of the leak inspection device or the object to be inspected with a sealing jig. And air pressure is applied to the reference tank, and whether or not there is a pressure difference between the two is used to determine whether or not the test object has a leak. In this mode, a room-temperature-dried test object without leakage is prepared, and a measuring jig for forming a closed space on the outer surface of the room-temperature-dry test object is attached via a sealing jig. Closed space for a predetermined time And, sealing the error value ΔP by sealing jig pressure change value after the lapse of a predetermined time in its closed state₀And the air pressure is applied to the room temperature dried test object, and the pressure change value during a predetermined time after the application of the air pressure is calculated as a drift value ΔP₀₁And a step of uniformly attaching water droplets to the inner surface and the outer surface of the room temperature dried test object facing the space formed by the measurement jig, and converting the room temperature dried test object to a normal temperature wet test object. Then, the wet portion of the specimen to be inspected at normal temperature is covered and closed by the measuring jig, and the pressure change value during the elapse of a predetermined time is determined by the vapor pressure ΔP₁And applying air pressure to the room temperature wet test object, and calculating a change in air pressure during a predetermined time after the application of the air pressure to the drift value ΔP of the wet test object.₁₁And the humidity correction coefficient k is calculated from the above measured values as k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀) And the sealing error value ΔP₀And a method of obtaining a humidity correction coefficient of the leak inspection apparatus, which executes the process of storing the humidity correction coefficient k in the storage device.
[0021]
According to the present invention, the sealing error value ΔP₀And a humidity correction method of the leak test apparatus storing the humidity correction coefficient k, wherein a part of the outer surface of the test object is covered with the measurement jig in the test mode to form a closed space, and the closed space is formed for a predetermined time. The pressure change value in the closed space is ΔP_XWhen the humidity correction value M is measured as M = (ΔP_X−ΔP₀) K, the humidity correction value M is removed from the drift value generated at the time of the leak test, and a humidity correction method of a leak test apparatus for correcting the humidity is proposed.
[0022]
In the present invention, a drift value corresponding to a temperature difference between an object to be inspected and a sealing jig is stored in a drift storage device by a drift value acquiring method of the leakage inspection device, and a humidity correction coefficient of the leakage inspection device according to claim 12. Depending on the acquisition method, seal error value ΔP₀3. A drift corresponding to a temperature difference between an object to be inspected and a sealing jig in a drift memory by a leak inspection method of a leak inspection device storing a humidity correction coefficient k and a drift value acquisition method of the leak inspection device according to claim 2. The seal error value ΔP is stored by the method for obtaining a humidity correction coefficient of the leak inspection apparatus according to claim 12.₀In any one of the leak inspection methods of the leak inspection device that stores the humidity correction coefficient k and the humidity correction coefficient k, in the inspection mode, the temperature difference between the test object and the sealing jig is measured, and the drift correction value corresponding to the temperature difference is measured. Is read from the drift storage unit, and the drift value is subtracted from the amount of change in the air pressure sealed in the test object to remove a drift component generated at the time of the leak test, and to remove a part of the outer surface of the test object from the above. Covered and closed with a measuring jig, sealed in an environment of atmospheric pressure, and the pressure change value ΔP from the sealed state until a predetermined time has elapsed._XAnd the pressure change value ΔP_XFrom the seal error value ΔP₀(ΔP_X−ΔP₀) Is multiplied by the humidity correction coefficient k to obtain a humidity correction value M in the inspection mode as M = (ΔP_X−ΔP₀) K, subtract the humidity correction value M from the amount of change in air pressure from which the drift component has been removed, and compare the subtraction result with a determination value for determining the presence or absence of leakage.
[0023]
According to the present invention, a seal jig for closing the opening of the test object, a temperature sensor for measuring a temperature difference between the seal jig and the test object, and a change in air pressure inside the test object are provided. Alternatively, a pressure sensor for measuring a pressure difference generated between the test object and the reference tank, and the normal temperature dry test object for each temperature difference between the test object and the seal jig which are not leaked in the calibration mode. A drift value acquisition unit that acquires a pressure change generated inside the test object as a drift value, a drift storage unit that stores the drift value for each of the temperature differences acquired by the drift value acquisition unit, A measurement jig which is attached to the outside of the room-temperature dried test object and forms a space closed by the concave portion, and a space formed by the measurement jig is closed, and the pressure sensor for measuring the vapor pressure in the closed state Measure with Seal error value ΔP from pressure changes that₀And a seal error value ΔP measured by the seal error measuring means.₀The seal error storage device that stores the data, and the room-temperature wet test object having no leakage in the calibration mode is closed by the measurement jig under the environment of the atmospheric pressure, and the closed state is measured by the vapor pressure measurement pressure sensor. Pressure change value ΔP₁And a pressure change value ΔP inside the cold-dried test object generated during a predetermined time period by applying air pressure to the cold-dry test object.₀₁And a pressure change value ΔP inside the cold-wet test object generated during a predetermined time period by applying air pressure to the cold-wet test object.₁₁Are measured, and these measurement results and the seal error value ΔP₀And the humidity correction coefficient k is given by k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀), A humidity correction coefficient memory storing the humidity correction coefficient k obtained by the humidity correction coefficient obtaining means, a test object and a sealing jig measured by the temperature sensor in the inspection mode. A drift writing / reading unit for reading a drift value corresponding to a temperature difference between the drift jig and the drift storage unit from the drift storage unit; and in an inspection mode, a space formed by the measurement jig is closed under an atmospheric pressure environment. Vapor pressure measuring means for correcting a pressure change inside the space during the period for humidity correction, and a measured value ΔP measured by the vapor pressure measuring means._XFrom the seal error value ΔP₀Is subtracted, and the subtracted value (ΔP_X−ΔP₀) Multiplied by the humidity correction coefficient k to obtain a humidity correction value M, and a drift read by the drift writing / reading means based on a change in air pressure enclosed in the test object in the inspection mode. A subtraction unit that subtracts the value and the humidity correction value M to perform drift correction and humidity correction, and a determination unit that compares the result of the subtraction with the set value and determines whether or not the inspection object has leaked. A leak inspection device constituted by the above is proposed.
[0024]
In the present invention, the opening of the test object is further closed by a sealing jig, air pressure is applied to the inside of the test object in this closed state, and the amount of change in the air pressure inside the test object after a predetermined time has elapsed. Measure and determine that there is leakage when the amount of decrease in air pressure is large, and that there is no leakage when the amount of decrease in air pressure is small.Close the opening of the leak inspection device or the object to be inspected with a sealing jig. And air pressure is applied to the reference tank, and whether or not there is a pressure difference between the two is used to determine whether or not the test object has a leak. In this mode, a room-temperature dried test object having no leakage is prepared, air pressure is applied to the room-temperature dried test object, and a pressure change value during a predetermined time after the application of the air pressure is applied to a drift value ΔP₀₁And the step of converting the cold-dried test object into a cold-wet test object by uniformly attaching water droplets to the outer surface of the cold-dry test object and the inner surface of the cold-dry test object, A wet part of the test object at normal temperature is covered with a measuring jig to form a closed space, a predetermined negative pressure is applied to the closed space, and the closed space is applied for a predetermined time after the application of the negative pressure. The pressure change value in the inside is determined by the vapor pressure ΔP₁And applying air pressure to the room temperature wet test object, and calculating a change in air pressure during a predetermined time after the application of the air pressure to the drift value ΔP of the wet test object.₁₁And the humidity correction coefficient k is calculated from the above measured values as k = (ΔP₁₁−ΔP₀₁) / ΔP₁) And a step of storing the humidity correction coefficient k in a storage device.
According to the present invention, there is further provided a humidity correction method for a leak test apparatus in which a humidity correction coefficient k is stored by a method for obtaining a humidity correction coefficient for the leak test apparatus, wherein a part of the outer surface of the test object is covered and closed by the measurement jig in the test mode. A space is formed, and a pressure change value in the closed space during the elapse of a predetermined time is ΔP_XIf the humidity correction value M is calculated as M = ΔP_X _・The present invention proposes a humidity correction method for a leak test apparatus that calculates the value of k and removes the humidity correction value M from a drift value generated during a leak test to correct the humidity.
[0025]
In the present invention, the drift value corresponding to the temperature difference between the test object and the sealing jig is stored in the drift storage device by the drift value acquiring method of the leak inspection device, and the humidity correction coefficient of the leak inspection device according to claim 16 is also provided. According to the leakage inspection method of the leakage inspection device in which the humidity correction coefficient k is stored by the acquisition method or the drift value acquisition method of the leakage inspection device according to claim 2, the drift storage device corresponds to the temperature difference between the test object and the sealing jig. In any one of the leak inspection methods of a leak inspection apparatus storing a drift value and storing a humidity correction coefficient k by the method for acquiring a humidity correction coefficient of the leak inspection apparatus according to claim 16, the inspection object and the seal are repaired in the inspection mode. The temperature difference between the sample and the test fixture is measured, and a drift correction value corresponding to the temperature difference is read out from the drift storage unit. Subtract from the change in air pressure, remove the drift component generated at the time of leakage inspection, seal the closed space formed by the test object and the measuring jig under a negative pressure environment, and wait a predetermined time from the sealed state. Pressure change value ΔP in the closed space up to the time when the elapsed time_XAnd the pressure change value ΔP_XIs multiplied by the humidity correction coefficient k to obtain a humidity correction value M in the inspection mode as M = ΔP_XA leak inspection method is proposed in which the humidity correction value M obtained by k is subtracted from the amount of change in air pressure from which the drift component has been removed, and the result of the subtraction is compared with a determination value for determining the presence or absence of leakage.
[0026]
According to the present invention, a seal jig for closing the opening of the test object, a temperature sensor for measuring a temperature difference between the seal jig and the test object, and a change in air pressure inside the test object are provided. Alternatively, a pressure sensor for measuring a pressure difference generated between the test object and the reference tank, and the normal temperature dry test object for each temperature difference between the test object and the seal jig which are not leaked in the calibration mode. A drift value acquisition unit that acquires a pressure change generated inside the test object as a drift value, a drift storage unit that stores the drift value for each of the temperature differences acquired by the drift value acquisition unit, A measurement jig that is attached to the outside of the room-temperature dry test object without any air and forms a space closed by the concave portion, and a part of the outer surface of the room-temperature wet test object that does not leak in the calibration mode and that is a measurement jig. Covered with , The measurement by applying a negative pressure to the closed space formed by the jig, pressure change value ΔP measured by the vapor pressure measurement pressure sensor during the predetermined time elapses in application state of the negative pressure₁And a pressure change value ΔP inside the cold-dried test object generated during a predetermined time period by applying air pressure to the cold-dry test object.₀₁And a pressure change value ΔP inside the cold-wet test object generated during a predetermined time period by applying air pressure to the cold-wet test object.₁₁And the humidity correction coefficient k is calculated as k = (ΔP₁₁−ΔP₀₁) / ΔP₁A humidity correction coefficient obtaining unit that obtains the humidity correction coefficient k obtained by the humidity correction coefficient obtaining unit, a test object and a sealing jig measured by the temperature sensor in the inspection mode. A drift writing / reading means for reading a drift value corresponding to a temperature difference between the drift storage and the drift storage, and applying a negative pressure to a space formed by the measurement jig in an inspection mode; Vapor pressure measuring means for humidity correction for measuring a pressure change inside the space, and a measured value ΔP measured by the vapor pressure measuring means_XA humidity correction value calculating means for multiplying the humidity correction coefficient k by the humidity correction coefficient k, and a drift value read by the drift writing / reading means from an amount of change in air pressure enclosed in the test object in the inspection mode. And a subtraction unit that subtracts the humidity correction value M and the drift correction and the humidity correction, and a determination unit that compares the result of the subtraction with the set value and determines whether or not the inspection object has leaked. We propose a leak inspection device configured with.
According to the present invention, in any of the leak inspection apparatuses, when a drift value corresponding to a temperature difference between the test object and the seal jig measured by the temperature sensor in the inspection mode does not exist in the drift storage device, There is proposed a leak inspection apparatus having a configuration provided with a linear approximation calculating means for calculating a drift value corresponding to a corresponding temperature difference by linear approximation from a plurality of drift values stored in the drift storage unit.
[0027]
Action
According to the drift value acquisition method of the leakage inspection device according to the present invention, the temperature difference between the test object and the seal jig is specified as a cause of the drift, and the drift is calculated for each temperature difference between the test object and the seal jig. Since the values are acquired and stored in the drift storage device, the drift value prepared in the drift storage device matches well with the drift value generated in the inspection mode, and the advantage that a highly accurate drift correction can be performed can be obtained. . Further, by applying the method for obtaining a humidity correction value of the leak inspection apparatus according to the present invention, even if the inspection target has water droplets attached thereto, the humidity correction value is obtained in advance, so that the time before the inspection or the end of the inspection can be determined. If the evaporative air pressure of the test object to be inspected is measured during any of the inspections except for the inspection, a humidity correction value can be obtained from the measured value. As a result, the drift caused by the temperature difference between the test object and the sealing jig and the error caused by the vapor pressure caused by the adhesion of the water droplet can be removed from the drift value obtained from the inspection result. The inspection can be correctly performed even on the inspected object.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an embodiment of a leakage inspection apparatus according to the present invention. According to this leak inspection apparatus, the drift value obtaining method and the humidity correction coefficient obtaining method for leak inspection according to the present invention can be executed. In addition, a highly reliable leak test can be performed using the drift value acquired by the drift value acquiring method and the humidity correction coefficient acquired by the humidity correction coefficient acquiring method.
In the figure, W indicates an object to be inspected. The test object W is placed on the first seal jig 1 serving as a base, and is kept airtight by a seal member CC such as an O-ring. The second seal jig 2 is mounted on the upper opening of the test object W, and closes the upper opening of the test object W. In this case, the sealing member CC mounted on the second sealing jig 2 is closed while maintaining airtightness.
[0029]
As the inspection object W, various products such as a cylinder block of an engine or parts of gas appliances are applied. When the shape is large like the cylinder block of the engine, the core 14 is inserted so that the internal volume in the inspection object W is reduced as much as possible.
The second sealing jig 2 is provided with an air inlet 2A, and a pipe 15 is connected to the inlet 2A. A pneumatic pressure source 20 is connected to the pipe 15 through a pressure sensor 16, a solenoid valve 17, a three-way solenoid valve 18, and a pressure regulating valve 19. The pressure adjusting valve 19 is adjusted to set the air pressure applied to the test object W according to the instruction of the pressure gauge 21.
[0030]
By controlling the three-way solenoid valve 18 to open between a and b and opening the solenoid valve 17, air pressure can be applied to the test object W. By closing the electromagnetic valve 17 after applying air pressure to the inspection object W, the air pressure can be confined in the inspection object W. By measuring the sealed air pressure with the pressure sensor 16, it is possible to determine that there is no leakage if a constant value is maintained for a predetermined time.
However, in general, the air pressure fluctuates (drifts) in accordance with the temperature of the inspection object W and the first seal jig 1 and the second seal jig 2, and the device behaves as if there is a leak. Further, the drift amount has a different value between the case where the test object W is in a dry state and the case where the test object W is wet.
[0031]
For this reason, in the present invention, there is provided a drift correction unit for performing drift correction assuming that the test object W is in a dry state, and a humidity correction unit for performing humidity correction to be performed assuming a wet state. A leak inspection device is provided. A leakage inspection apparatus main body 100 shown in FIG. 1 is a leakage inspection apparatus main body including a schematic drift correction unit 30, a humidity correction unit 50, and a determination unit 70. Although details of the inside of the leakage inspection apparatus main body 100 according to the present invention will be described with reference to FIG. 2, here, an outline of the leakage inspection apparatus main body 100 will be described.
[0032]
The drift correction unit 30 is provided with a drift storage unit 30B that stores a drift correction value obtained in advance in the calibration mode. The drift correction value stored in the drift storage unit 30B prepares the inspection object W in a dry state without leakage. It is required that the test object having no leakage has the same shape and the same material as the product to be inspected for the presence or absence of leakage. An air pressure is applied to the test object W, and after a predetermined stabilization time has passed after the application of the air pressure, a predetermined measurement period (for example, about 2 to 4 seconds) is set. Obtain the pressure change as a drift value. At this time, the temperature difference between the test object W and the first seal jig 1 is measured and stored in the drift storage device 30B as a drift value at the temperature difference. In the calibration mode, the test object W is heated or cooled to set the temperature difference between the test object W and the first seal jig 1 to a different temperature difference, and a drift value is obtained for each temperature difference. The acquired drift value is stored in the drift storage 30B.
[0033]
A temperature sensor 3 is provided on the first seal jig 1 to measure a temperature difference between the test object W and the seal jig (the first seal jig 1 in the example shown in FIG. 1). As shown in FIG. 3, the temperature sensor 3 has a hole H formed on the surface of the first seal jig 1 that contacts the inspection object W, and a sensor holder 13 is mounted inside the hole H. The sensor holder 13 has a through hole 13A in the axis thereof, and temperature sensors S1 and S2 are mounted and supported on both ends of the through hole 13A. The temperature sensors S1 and S2 are disposed so as to be exposed at both end surfaces of the through hole 13A. The temperature sensor S1 comes into contact with the first seal jig 1 to measure the temperature of the first seal jig 1. It is arranged to be exposed at the upper end surface of the through hole 13A. These sensors S1 and S2 are fixed to the sensor holder 13 with a resin or an adhesive inside the through hole 13A.
[0034]
The temperature sensor S2 is arranged flush with the surface of the first seal jig 1. When the test object W is mounted thereon, the test object W contacts the sensor S2 and measures the temperature of the test object W. . Note that a metal plate or the like made of a material having high thermal conductivity such as copper may be disposed on the surface of the sensor S2 for protection, and the sensor S2 may be configured to be in contact with the inspection object W via the metal plate. .
The temperature difference measuring device 4 obtains the difference between the measured temperatures of the sensors S1 and S2, and inputs the temperature difference between the inspection object W and the first sealing jig 1 to the leak inspection device main body 100.
[0035]
In this manner, the drift value acquired in advance for each temperature difference between the test object W and the sealing jig 1 in the calibration mode is stored in the drift storage device 30B.
In the inspection mode, prior to the inspection, a temperature difference between the inspection object W and the sealing jig 1 is measured, a drift value corresponding to the temperature difference is read from the drift storage unit 30B, and the drift value is inspected for the inspection object. Drift correction is performed by subtracting the value from the drift value generated in the case of the above.
On the other hand, the humidity correction value calculation means 50 is provided with a humidity correction coefficient acquisition means 50C, a humidity correction coefficient storage unit 50D, and a vapor pressure measurement means 50E for measuring the degree of attachment of water droplets to the test object W. ing. The humidity correction coefficient acquisition means 50C includes a drift value generated in each of the test objects using a leak-free test object that is dry in a normal temperature state in a calibration mode and a wet normal temperature test object to which water droplets are attached. Is measured, a humidity correction coefficient k is obtained from the drift value, and the humidity correction coefficient k is stored and prepared in the humidity correction coefficient storage unit 50D.
[0036]
At the same time, in the inspection mode, the vapor pressure generated when water drops are present for each test object is measured by the vapor pressure measuring means 50E, and a humidity correction value M is obtained from the vapor pressure and the humidity correction coefficient k. The correction value M is subtracted from a drift value generated in the test object (specifically, a drift value subjected to drift correction) to perform humidity correction.
The determination unit 70 compares the drift value subjected to the drift correction and the humidity correction with a predetermined determination value, and determines that there is leakage when the drift value exceeds the determination value, and that there is no leakage when the drift value is equal to or less than the determination value. Then, the determination result is displayed on the display 200.
[0037]
FIG. 2 shows the internal configuration of the leakage inspection apparatus main body 100. The leak inspection device main body 100 is generally configured by a computer. The computer includes a central processing unit 101 called a CPU, a ROM 102 storing a basic program, a RAM 103 for recording and executing a production program and the like, an input port 104, an output port 105, and the like.
The embodiment shown in FIG. 2 shows a case in which a real program is read into the RAM 103 from, for example, an external magnetic disk or the like, and each of the real programs is executed on the RAM 103. The production program may be burned into the ROM 102 and executed on the ROM 102 in some cases.
[0038]
The RAM 103 is provided with a drift value acquiring unit 30A, a drift storage unit 30B, and a drift writing / reading unit 30C as units constituting the drift correcting unit 30.
Further, as means constituting the humidity correction means 50, a seal error measurement means 50A, a seal error storage 50B, a humidity correction coefficient acquisition means 50C, a humidity correction coefficient storage 50D, a vapor pressure measurement means 50E, a humidity correction Value calculation means 50F is provided. Further, a subtraction unit 60 and a determination unit 70 are provided.
[0039]
A pressure measurement value from the pressure sensor 16 and a temperature difference value between the test object W and the sealing jig 1 from the temperature difference measuring device 4 are input to the input port 104. A display 200 is connected to the output port 105, and the result of the determination by the determination means 70 is displayed on the display 200.
The drift value acquisition means 30A is configured by a program. The program constituting the drift value acquiring means 30A is selected and activated in the calibration mode. When the program constituting the drift value acquiring means 30A is started, the drift value for each temperature difference between the inspection object W and the sealing jig 1 is acquired according to the procedure shown in FIG.
[0040]
In step S41 shown in FIG. 4, a dried test object without leakage is prepared and placed on the sealing jig 1.
In step S42, heat is applied to the test object W to set a temperature difference between the test object W and the sealing jig 1 to a desired temperature difference.
In step S43, the opening of the test object W is closed by the second seal jig 2 (see FIG. 1), and the electromagnetic valve 17 is opened to apply air pressure to the test object W.
In step S44, the pressure change value D generated during the measurement period T3 (see FIG. 5) is measured as a drift value, and the measurement result is stored in the drift storage device 30B by the drift writing / reading means 30C (FIG. 1). FIG. 5 shows a sequence for applying air pressure to the inspection object W. T1 indicates a pressurization period, T2 indicates an equilibrium period, and T3 indicates a measurement period. Each period is set to about 3 to 5 seconds.
[0041]
In step S45, it is determined whether the drift value has been obtained over all of the desired temperature differences. If a part of the desired temperature difference has not been obtained yet, the process returns to step S42, and steps S42 to S44 are executed again. If the drift values have been obtained over all the temperature differences, the process ends. FIG. 6 shows an example of the drift value acquired by the drift storage device 30B. As shown on the horizontal axis in FIG. 6, a temperature difference is assigned to each storage address, and a drift value is stored for each temperature difference.
Next, a method of acquiring a humidity correction coefficient will be described. The acquisition of the humidity correction coefficient is also executed in the calibration mode. FIG. 7 shows a procedure of a humidity correction coefficient acquisition method.
[0042]
In step S71, a room-temperature-dried inspection object having no leakage is prepared and placed on the sealing jig 1. Since the temperature of the test object is room temperature, the temperature difference from the seal jig 1 is zero.
In step S72, the opening of the test object is closed with the second seal jig 2 under the atmospheric pressure environment, and the atmospheric pressure is sealed inside the test object W.
In step S73, the pressure change value ΔP inside the test object during a predetermined time (for example, about several seconds) elapses.₀Is measured. This pressure change value corresponds to a change in steam pressure during drying, and this also corresponds to a seal error value of the seal jig 2 (an error generated due to deformation of the shape of the seal jig or the like). Below ΔP₀Is referred to as a seal error value.
[0043]
In step S74, air pressure is applied to the room-temperature dried test object, and the drift value ΔP in the dry state is applied.₀₁Is measured.
In step S75, the same test object is converted into a wet test object by attaching water droplets to the inner surface of the test object. In this state, the opening of the test object is closed, and the atmospheric pressure is sealed in the test object. , The vapor pressure change value ΔP during the elapse of a predetermined time₁Is measured.
In step S76, air pressure is applied to the test object, and the pressure change value ΔP generated during the measurement period T3 (see FIG. 5)₁₁Is measured.
[0044]
In step S77, the humidity correction coefficient k is calculated.
k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀)
Is calculated and the processing is terminated.
Note that ΔP calculated in step S77₁−ΔP₀Is the seal error value ΔP from the change in the vapor pressure of the wet test object.₀Is the change in the vapor pressure. Also, ΔP₁₁−ΔP₀₁Is the drift value ΔP of the wet test object₁₁Value ΔP of the test object dried from the₀₁Is the drift value due to the vapor pressure after subtracting.
[0045]
When the humidity correction coefficient k is calculated, the humidity correction coefficient k is stored in the humidity correction coefficient storage 50D shown in FIG.
Thus, the calibration mode can be ended. The calibration mode described above does not need to be performed frequently unless the inspection object (product to be inspected) is changed, and may be performed every time the type of the inspection object is changed. However, when calibration is performed in advance for each product and necessary data is stored, it is not always necessary.
Next, the inspection mode will be described. In the inspection mode, the test object W is placed on the first seal jig 1, and the opening of the test object W is also closed by the second seal jig 2. In this closed state, the atmospheric pressure is sealed in the inspection object W. In this closed state, the pressure is measured by the vapor pressure measuring means 50E shown in FIG. The vapor pressure change value measured at an arbitrary test object W is ΔP_X, The humidity correction value calculating means 50F calculates the humidity correction value M as
M = (ΔP_X−ΔP₀) K
Is calculated.
[0046]
In the subtraction means 60, the drift correction means 30 calculates the drift value correction value D obtained from the temperature difference between the test object W and the seal jig 1 for each test object W.₀And the humidity correction value M obtained by the humidity correction means 50 (D₀+ M), and subtract the result of this addition from the pressure change value E measured for each test to obtain a drift-corrected and humidity-corrected value F,
F = E- (D₀+ M)
Ask for.
The determination means 70 compares the drift-corrected value F with a determination value Y for leakage determination, and determines that there is no leakage if F <Y and that there is leakage if F> Y.
[0047]
FIG. 8 shows the state of the inspection. Here, prior to the inspection, the vapor pressure change value ΔP_XShows a case in which a vapor pressure change value measurement period T0 in which is measured is provided. During the vapor pressure change value measurement period T0, the vapor pressure change value ΔP_XIs measured. After the measurement, the measurement period T3 is reached after the pressurizing period T1 and the equilibrium period T2. During the measurement period T3, the pressure change value E (see FIG. 8) inside the test object W is measured. At the same time, the drift correction means 30 reads the drift correction value D from the drift storage 30B according to the temperature difference between the test object W and the sealing jig 1.₀Is read. Further, the humidity correction means 50 calculates a humidity correction value M.
[0048]
The subtraction means 60 calculates a drift correction value D from the measured pressure change value E.₀And the humidity correction value M (D₀+ M) is subtracted, and the drift-corrected value F subjected to the drift correction and the humidity correction is calculated as F = E− (D₀+ M).
E ≒ D if there is no leak in the test object W₀+ M. In this case, F ≒ 0, so that F <Y, and it is determined that there is no leakage. If there is leakage, E> D₀+ M, so that Y <E− (D₀+ M), and the probability of determining that there is leakage is increased.
[0049]
By the way, in the above-described embodiment, the example in which the drift value for each temperature difference is stored in all the addresses of the drift storage device 30B as shown in FIG. 6 has been described. Since the method of setting the temperature of the body W to an appropriate temperature and setting the temperature difference with the sealing jig 1 based on the temperature and measuring the drift value is adopted, the larger the number of addresses for obtaining the drift value, the more the labor becomes. Is big.
For this purpose, a method is conceivable in which the drift values are stored only in several addresses in the drift storage device 30B, and the drift values of other addresses are obtained by linear approximation.
[0050]
FIG. 9 shows the embodiment. That is, this embodiment is characterized in that the drift correction means 30 is provided with a linear approximation calculating means 30D in addition to the structure shown in FIG.
By providing the linear approximation means 30D, as shown in FIG. 10, for example, about three points of 0 ° C., + 15 ° C., and + 30 ° C. are set as the temperature differences, and the drift values D1, D2 for each of these temperature differences are set. , D3 are stored and prepared, the drift values of other temperatures can be calculated by the linear approximation calculating means 30D. Further, if the temperature difference to be calculated can be calculated even after the decimal point, even if the measured temperature difference includes a decimal point, for example, 13.5 ° C., the drift value D corresponding to the temperature difference is obtained._MCan be requested.
[0051]
Therefore, according to the embodiment shown in FIG. 9, the effect of greatly reducing the effort to obtain the drift value for drift correction and the advantage that the drift value corresponding to the measured temperature difference can be accurately obtained. Is obtained.
FIG. 11 shows still another embodiment of the present invention. This embodiment is characterized in that the leakage inspection apparatus main body 100 shown in FIG. 9 is provided with a zero point fluctuation value storage unit 30E and a zero point fluctuation writing / reading means 30F. The zero point fluctuation value storage unit 30E stores, as a zero point fluctuation value, an amount ΔD in which the drift value D fluctuates due to, for example, a seasonal change. The reason why the zero point variation value ΔD occurs is that when the average temperature (environmental temperature) of the test object W and the sealing jig 1 fluctuates according to the season, the temperature change of the air sealed in the test object W ( It is considered that the main cause is that the drift amount due to adiabatic fluctuation) fluctuates. A method of acquiring the amount by which the drift value D fluctuates and the zero point fluctuation value ΔD will be described.
[0052]
There are the following two methods for acquiring the zero point variation value ΔD.
{Circle around (1)} An inspection object W having no leakage is prepared, and the temperature difference between the inspection object W and the first sealing jig 1 is set to the temperature difference N ° C. existing in the drift memory 30B. In this state, the drift value G and the environmental temperature (the temperature of the sealing jig or the atmospheric temperature) at this time are measured in the measurement period T3 after the pressing period T1 and the parallel period T2. A deviation ΔD = GD from the drift value G and the drift value D stored at an address corresponding to N ° C. in the drift storage unit 11F is obtained. This deviation ΔD is the zero point fluctuation value under the environmental temperature at the time of performing this calibration.
[0053]
{Circle around (2)} The temperature difference between the test object W and the first seal jig 1 is set to 0 ° C. In this case, the inspection object W does not matter whether or not there is leakage. The reason why the drift value can be measured using a test object having leakage (however, the leakage is not a large leakage but a small leakage) will be described later. Here, only the procedure is shown in FIG. A simple explanation is given below. At the end of the measurement period T3 after the pressurization period T1 and the equilibrium period T2, the pressure change D1 of the pressure gauge 16 is measured. Thereafter, from time A when a sufficient time (time until the drift ends, about several minutes), pressure change values D2 and D3 that change during the time T3 that is the same as the previous measurement period T3 are measured. , The difference ΔD2 = D2−D3 is obtained. Since the difference ΔD2 is a pressure change value generated by leakage, a true drift value G can be obtained by subtracting the difference ΔD2 from the first measurement value D1. That is, G = D1−ΔD2. If there is a difference ΔD = GD between the drift value G and the drift value D stored in the address of the temperature difference 0 ° C. in the drift storage device 30B, the difference ΔD is determined at the current environmental temperature. This is the zero point fluctuation value. The deviation ΔD has a positive or negative polarity (see FIG. 12).
[0054]
Even if the zero point fluctuation value ΔD is obtained by any of the methods (1) and (2), the zero point fluctuation value ΔD is written and stored in the zero point fluctuation value storage unit 30E by the zero point fluctuation writing / reading means 30F. You can do it. In the inspection mode, the zero point variation value ΔD read by the zero point writing / reading means 30F is added to the drift value D read from the drift storage device 30B by the drift writing / reading means 30C, and the addition result is being inspected by the subtraction means 60. Is subtracted from the pressure change value E (FIG. 8) obtained from the test object W, and the result of the subtraction is sent to the judgment means 70. Further, the humidity correction value M is also obtained by the humidity correction means 50, and this humidity correction value M is also sent to the subtraction means 60 to perform the humidity correction.
By adding the zero point variation value ΔD to all the drift values D read from the drift storage device 30B in the inspection mode and performing drift correction, the original curve A shown in FIG. Will be modified. It can be easily understood that the embodiment shown in FIG. 9 and the embodiment shown in FIG. 11 can be implemented in combination.
[0055]
FIG. 14 shows still another embodiment of the present invention. This embodiment shows a case where the inspection object W has one opening. In this case, the temperature difference between the second seal jig 2 and the test object W is measured by the temperature sensor 3, and the temperature difference is obtained by the temperature difference measuring device 4 and input to the leak inspection device main body 100. Good. Accordingly, also in this case, the drift value D is read from the drift storage device 30B in accordance with the temperature difference obtained by the temperature difference measuring device 4, and the drift value D is read out from the device under test W as in the embodiment shown in FIG. Drift correction is performed by subtracting from the pressure change value E (see FIG. 4) measured in step (1). Further, the embodiment shown in FIGS. 9 and 11 can be used together with this embodiment. Further, a humidity correction value M is obtained by the humidity correction means 50, and humidity correction is performed using the humidity correction value M.
FIG. 15 shows still another embodiment of the present invention. In this embodiment, a case is shown in which the temperature sensor 3 is constituted by contact-type temperature sensors 3A and 3B. By using the contact-type temperature sensors 3A and 3B, the contact position with respect to the inspection object W and the second seal jig 2 can be arbitrarily set and changed, so that a position suitable for measuring a temperature difference is provided. Can be freely selected. It should be noted that there are some types of test object W whose temperature cannot be measured by a contact-type thermometer. In such a case, it is conceivable to measure the temperature of the inspection object W using a non-contact type infrared radiation thermometer, for example.
[0056]
FIG. 16 shows a case where the present invention is applied to a differential pressure detection type leakage inspection device. As is well known, the differential pressure detection type leakage inspection device is provided with a reference tank MS having no leakage with respect to the test object W, and the solenoid valves 17A and 17B are opened and closed between the test object W and the reference tank MS. Enclose air pressure. In an air-filled state (a state in which the solenoid valves 17A and 17B are closed), a pressure difference between the reference tank MS and the test object W is determined by a differential pressure gauge 16A provided between the reference tank MS and the test object W. Measure whether it occurs. This is a type of leakage inspection device that determines that the inspection object W has leakage when a differential pressure is generated.
[0057]
In the case of this differential pressure detection type leak test, since the same air pressure as the air pressure applied to the test object W is sealed in the reference tank MS, the differential pressure gauge 16A should originally detect zero pressure difference. However, similarly to the embodiment shown in FIGS. 1 and 2, a pressure change (drift) occurs in the air sealed in the inspection object W, and a differential pressure occurs as if there is a leak.
In the present invention, first, in the calibration mode, a room-temperature dried inspection object W having no leakage is prepared, and a temperature is applied to the inspection object W, and in the example shown in FIG. Set the state that gave the difference. In this state, the measurement period T3 is executed after the pressurization period T1 and the equilibrium period T2, the drift value is measured for each temperature difference, and the drift value is obtained at a plurality of addresses of the drift storage device 30B. I do. Further, the humidity correction coefficient k is obtained according to the procedure described with reference to FIG. 7, the calibration mode is terminated, and the inspection can be performed thereafter.
[0058]
In the inspection mode, as shown in FIG. 17, each time the inspection starts, the vapor pressure change value ΔP_X(In the differential pressure type leak inspection device, a change in vapor pressure at which the pressure in the inspection object W increases is detected as a negative pressure difference as shown in FIG. 17). The humidity correction means 50 calculates the measured vapor pressure change value ΔP_XThe humidity correction value M is calculated from the humidity correction coefficient k.
In the inspection mode after the pressurization period T1, when the differential pressure value rises sharply in the equilibrium period T2 (the straight line X shown in FIG. 17), it is determined that the inspection object W under inspection has "large leak". . Drift value D read out from drift storage device 30B from differential pressure value E generated between test object W under inspection and reference tank MS at the end of determination period T3.₀A value F obtained by subtracting the sum of the above and the humidity correction value M obtained earlier is given by F = E− (D₀+ M). Here, the humidity correction value M is such that the vapor pressure change value is ΔP_XTherefore, the humidity correction value M is M = (ΔP_X−ΔP₀) Find with k. Therefore, F = E- (D₀+ M). E- (D₀+ M) ≒ 0, then almost F ≒ 0. In this case, it is determined that there is no leakage. If F is larger than the determination value Y, it is determined that "there is leakage".
[0059]
It can be easily understood that the embodiment shown in FIGS. 9, 11 and 15 can be used in combination with the embodiment shown in FIG.
FIG. 18 shows still another embodiment of the present invention. This embodiment is a modification of the embodiment shown in FIG. That is, in the embodiment shown in FIG. 11, a zero-point fluctuation value storage unit 30E is provided, and the zero-point fluctuation value storage unit 30E stores the zero-point fluctuation value for each season. The embodiment has been described in which a configuration for correcting the drift value read from the 30B and correcting the fluctuation of the drift value due to the change in the environmental temperature is added. According to the embodiment shown in FIG. 11, there is an inconvenience that the calibration mode for acquiring the zero point fluctuation value for each season must be executed.
[0060]
The embodiment shown in FIG. 18 proposes a leak inspection apparatus which can solve this inconvenience.
For this purpose, the zero point fluctuation value storage unit 30E shown in FIG. 11 is changed to a zero point fluctuation value storage unit 30E 'capable of storing zero point fluctuation values of a plurality of environmental temperatures. 5 is provided.
The environmental temperature measuring means 5 shown in FIG. 18 can be configured so that, for example, a temperature measurement value obtained by measuring the temperature of the first seal jig 1 with the temperature sensor 3 is used as the environmental temperature.
[0061]
The zero point fluctuation value is obtained by either the zero point fluctuation value acquisition method (1) or (2) described with reference to FIG. 11, and the environmental temperature at that time is made to correspond to the address of the zero point fluctuation value storage 30E '. Remember. FIG. 19 shows the ambient temperature T._SShows the tendency of the zero point variation value ΔD with respect to FIG. 19 shows the ambient temperature T._SShows a case where the zero point variation value ΔD tends to gradually decrease as the value increases.
At the time when the leak inspection device is manufactured and handed over to the user, no data is written in the drift storage device 30B (see FIG. 2) and the zero point variation value storage device 30E '. The drift memory 30B stores the drift value by the drift value acquisition method proposed in the present invention. At the same time, the zero-point fluctuation value of the environmental temperature at that time can be written in the zero-point fluctuation value storage unit 30E '. Therefore, at the start of operation, only one zero-point fluctuation value is written in the zero-point fluctuation value storage unit 30E. This zero point fluctuation value can be used effectively in that season (under environmental temperature).
[0062]
Every time the season ends and the environmental temperature changes, the zero-point fluctuation value is obtained and written to the zero-point fluctuation value storage 30E 'throughout the year, so that the zero-point fluctuation value is stored in almost the entire address shown in FIG. Can be captured. Even if there is an address (environmental temperature) at which the zero point fluctuation value cannot be captured, the zero point fluctuation value of that address can be obtained by linear approximation by the linear approximation calculating means 30D. Therefore, in this embodiment, the straight-line approximation means 30D calculates both straight lines when there is no drift value to be read from the drift storage device 30B and when there is no zero-point variation value to be read from the zero-point variation value storage device 30E '. Act as a means to perform approximation.
[0063]
The zero point fluctuation value is measured throughout the year, and the measurement result is written to the zero point fluctuation storage device 30E '. Thereafter, the zero point fluctuation value corresponding to the environmental temperature is directly or linearly stored from the zero point fluctuation value storage device 30E'. It can be obtained from the approximate calculation means 30D.
Therefore, the drift value read from the drift storage unit 30B is corrected using the zero point variation value, and the corrected drift value is changed to the pressure change value E generated in the inspection object W under inspection (see FIGS. 8 and 9). 17), the drift value can be correctly removed throughout the four seasons. Therefore, from the time when the zero-point fluctuation value can be stored in the zero-point fluctuation value storage device 30E 'over a plurality of environmental temperatures, it is possible to perform the leak inspection fully automatically without executing the calibration mode at all. Is obtained.
[0064]
FIG. 20 shows a case where the embodiment shown in FIG. 18 is applied to a differential pressure type leak inspection apparatus. Even in the case of a differential pressure type leak inspection device, the leak inspection device main body 100 is provided with a zero point variation value storage device 30E 'capable of storing a zero point variation value for each environmental temperature, and the environmental temperature measuring means 5 is provided. Can be In this embodiment, a case is shown in which the temperature of the second seal jig 2 is taken into the leak inspection apparatus main body 100 as the environmental temperature.
Even in the case of the differential pressure type leakage inspection device, first, a drift value for each temperature difference between the inspection object and the sealing jig is prepared in the drift storage device 30B (see FIG. 2) using the inspection object without leakage. The zero point fluctuation value is obtained by the zero point fluctuation value obtaining method (1) or (2) described with reference to FIGS. 11 and 12, and the zero point fluctuation value is obtained at the address of the zero point fluctuation memory 30E 'corresponding to the environmental temperature at that time. The zero point fluctuation value is stored. The acquisition of the zero-point fluctuation value is performed for each environmental temperature, the zero-point fluctuation value is fetched into a plurality of addresses of the zero-point fluctuation value storage unit 30E ′, and the humidity correction coefficient k is calculated by the humidity correction value calculation unit 50. By obtaining this, the leak inspection can be performed fully automatically thereafter.
[0065]
By the way, in the above-described embodiment, the vapor pressure change inside the test object W is measured in order to obtain the humidity correction value M. However, when this method is adopted, the inside of the test object W The vapor pressure change of the must be measured.
For this reason, the time required for the inspection becomes longer by the measurement time T0 (see FIG. 8 or FIG. 17) of the change in vapor pressure. This extension of the time becomes longer in total as the number of the inspected objects W increases, so that an expensive inspection apparatus is dedicated for a long time, and there is a disadvantage that the inspection cost becomes expensive.
[0066]
For this reason, the present invention further proposes a leak inspection apparatus for detecting the wet state of the test object W using the external surface of the test object W as a substitute.
FIG. 21 shows the embodiment. In this embodiment, the measuring jig 80 is brought into contact with the outer surface (flat surface) of the test object W via the sealing member CC, and the space sealed on the outer surface of the test object W by the concave portion 81 of the measuring jig 80. 82 is formed, and a change in the vapor pressure in the space 82 is measured by measuring the change in pressure in the space 82 and the pressure sensor 83 for measuring the vapor pressure.
[0067]
In this configuration, in the calibration mode,
{Circle around (1)} The sealing error is caused by pressing the measuring jig 80 against the outer wall of the dry and non-leak test object W at room temperature without any leakage. It is opened to reset the inside of the space 82 to the atmospheric pressure, and the solenoid valve 84 is closed again. A pressure change at a point several seconds after the closing of the solenoid valve 84 is measured by the vapor pressure measuring pressure sensor 83, and the measured value is used as a seal error ΔP₀And
(2) Next, air pressure is applied to the same test object W, and a pressure change value in the test object W is measured by the differential pressure gauge 16A in the example of FIG. The differential pressure value is the drift value ΔP in the state where the temperature difference between the test object W and the sealing jig 1 in the dried normal temperature test object is 0 ° C.₀₁Get as
[0068]
{Circle around (3)} Using the same test object W, water droplets are evenly attached to the inside and outside of the test object W to convert it into a wet test object. (If the whole work is wet and left for a while, it will be evenly painted both inside and outside.)
{Circle around (4)} Put the measuring jig 80 on the outer surface of the test object to which the water droplets adhere,₀After the electromagnetic valve 84 is opened and the space 82 is reset to the atmospheric pressure, the electromagnetic valve 84 is closed, and the pressure change value several seconds later is measured by the pressure sensor 83 for measuring the vapor pressure. This value is ΔP₁And the vapor pressure change value of the wet test object.
[0069]
{Circle around (5)} The opening is closed with the same inspection object W with the sealing jig 2, air pressure is applied to the inside of the inspection object W, and the pressure change value during the elapse of a predetermined time is measured by the differential pressure gauge 16 A in this example. And this value is calculated as the drift value ΔP of the wet test object.₁₁Get as
(6) From these measurement results, the humidity correction coefficient k
k = (ΔP₁₁−ΔP₀₁) / (ΔP₁−ΔP₀)
The humidity correction coefficient k and the seal error value ΔP₀Is stored in the humidity correction means 50.
Thus, the calibration mode in the embodiment shown in FIG. 21 ends.
[0070]
In inspection mode
{Circle around (1)} The measuring jig 80 is attached to the outer wall of the inspection object W, and the vapor pressure change ΔP due to the wetting of the outer wall of the inspection object W_XIs measured.
(2) This vapor pressure change ΔP_XFrom seal error ΔP₀Is multiplied by a humidity correction coefficient k to obtain a humidity correction value M.
M = (ΔP_X−ΔP₀) K
{Circle around (3)} A pressure change E (drift value) inside the test object W is measured, and a drift correction value D read from the pressure change E according to a temperature difference between the test object W and the sealing jig 2.₀A value F subjected to the drift correction and the humidity correction is obtained by subtracting the humidity correction value M (stored in the drift correction means 30) and the humidity correction value M.
F = E- (D₀+ M)
{Circle around (4)} F is compared with the determination value Y. If Y> F, there is no leakage, and if Y <F, there is leakage, and the inspection is terminated.
Thus, even if the wet state of the test object W is measured outside the test object W, it is considered that there is a correlation between the inside and the outside of the test object W. As in the case of using and calibrating, it is possible to perform a leak test with humidity correction.
[0071]
Here, in particular, in the test mode, the vapor pressure measurement performed for each test object in the test mode, as shown in FIG. 22A, a pressurizing period T1 for measuring a pressure change inside the test object W, an equilibrium period T2, and a measurement period. It may be performed at any time during the execution of the period T3, which is a great feature in that a leak test with humidity correction can be performed in the same time as the time required for the conventional test.
By the way, when the inside of the measuring jig 80 is measured at the atmospheric pressure when measuring the change in the vapor pressure, the measurement time T is required to accurately measure the change in the vapor pressure.₀(See FIG. 8 or FIG. 17). On the other hand, it has been found that when the change in the vapor pressure is measured while the inside of the measuring jig 80 is at a negative pressure, the change in the vapor pressure can be accurately measured in a short time. It is considered that the reason for this is that, by setting the inside of the measuring jig 80 to a negative pressure, the evaporation of water is promoted, and the pressure change due to the evaporation of water is greatly generated in a short time.
[0072]
FIG. 23 shows an embodiment in which the inside of the measuring jig 80 is set to a negative pressure, the vapor pressure is measured, and the amount of moisture adhering to the inspection object W is measured.
In this embodiment, a negative pressure generator (vacuum pump) 85 is connected to the open end of the solenoid valve 84, and a negative pressure is applied to one end of the solenoid valve 84. When measuring the vapor pressure, after the measurement jig 80 is attached to the outer wall of the test object W, the electromagnetic valve 84 is controlled to be opened, and the vapor pressure measurement pressure sensor 83 reaches a predetermined negative pressure. Is detected, the electromagnetic valve 84 is closed with the negative pressure, and the change in the pressure inside the measuring jig 80 during a predetermined time from that point is determined by the steam pressure change value ΔP₁Measured as
In the calibration mode, this vapor pressure change value ΔP₁Is the same as above, but in this case, in particular, the sealing error ΔP₀Has the advantage that it is not necessary to measure and store That is, since the air inside the measuring jig 80 is sucked to a negative pressure, a phenomenon in which the pressure inside the measuring jig 80 fluctuates due to deformation of the sealing member CC or the like does not occur.
Therefore, the humidity correction coefficient k obtained in the calibration mode is
k = (ΔP₁₁−ΔP₀₁) / ΔP₁
Is required.
Further, in the inspection mode, the vapor pressure change value measured in the inspection mode is ΔP_xIf the humidity correction value M obtained in the inspection mode is
M = ΔP_x・ K
Is required.
Therefore, when humidity correction is performed by measuring the vapor pressure by setting the inside of the measuring jig 80 to a negative pressure, in addition to the advantage that the vapor pressure change can be accurately measured in a short time, the sealing error ΔP₀The advantage of not having to perform the measurement is obtained.
[0073]
【The invention's effect】
As described above, according to the present invention, the drift correction value is obtained by using the dried test object, and the humidity correction value M is calculated by the humidity correction coefficient k obtained by using the wet test object. In addition, the influence of humidity can be removed from drift correction. In addition, the influence of drift correction during drying can be eliminated in humidity correction.
As a result, the drift in a dry state and the drift due to humidity generated in a wet test object can be almost completely removed, and a highly reliable leak test can be performed.
[0074]
Further, when the zero point fluctuation values generated at a plurality of environmental temperatures are stored in the zero point fluctuation value storage unit 30E ', respectively, Even if it changes to the environmental temperature, the zero point drift value of the environmental temperature at that time can be obtained, so that the leak inspection device can be driven fully automatically throughout the four seasons. As a result, it is not necessary to periodically execute the calibration mode, so that the operating rate of the leak inspection apparatus can be improved, and the advantage that the inspection cost can be expected to be reduced can be obtained.
Further, according to the embodiment shown in FIGS. 21 and 23, even if the humidity correction is performed, the time required for the inspection does not become long, so that the embodiment is suitable for inspecting a large number of inspected objects. According to the embodiment shown in FIG. 23, in addition to the advantage that the vapor pressure can be measured accurately in a short time, the seal error ΔP₀Is not required to be measured and stored, so that the advantage that the apparatus can be simplified is also obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram for explaining an embodiment of a leakage inspection apparatus according to the present invention.
FIG. 2 is a block diagram for explaining a configuration of a main part of the leakage inspection device shown in FIG. 1;
FIG. 3 is a cross-sectional view for explaining an example of a structure of a temperature sensor used in the leakage inspection device shown in FIG.
FIG. 4 is a flowchart for explaining a procedure of a drift value acquisition method according to the present invention.
FIG. 5 is a graph for explaining the operation of the leakage inspection device shown in FIG. 1;
FIG. 6 is a graph for explaining an example of a drift value stored in the drift storage device shown in FIG.
FIG. 7 is a flowchart illustrating a procedure of a humidity correction coefficient acquisition method according to the present invention.
FIG. 8 is a graph for explaining the operation of the leakage inspection device shown in FIGS. 1 and 2 in an inspection mode.
FIG. 9 is a block diagram for explaining a modified embodiment of the present invention.
FIG. 10 is a graph for explaining the operation of the modified example shown in FIG. 9;
FIG. 11 is a block diagram for explaining still another modified embodiment of the present invention.
FIG. 12 is a graph for explaining the operation of the main part of the modified embodiment shown in FIG. 11;
FIG. 13 is a graph for explaining a zero point fluctuation value acquisition method used in the embodiment shown in FIG. 11;
FIG. 14 is a block diagram for explaining still another modified embodiment of the present invention.
FIG. 15 is a block diagram for explaining still another embodiment of the present invention.
FIG. 16 is a block diagram for explaining still another embodiment of the present invention.
FIG. 17 is a graph for explaining the operation of the embodiment shown in FIG. 16;
FIG. 18 is a block diagram for explaining another embodiment of the embodiment shown in FIG. 16;
FIG. 19 is a graph for explaining the operation of the embodiment shown in FIG. 18;
FIG. 20 is a block diagram for explaining another embodiment of the embodiment shown in FIG. 16;
FIG. 21 is a block diagram for explaining still another embodiment of the present invention.
FIG. 22 is a graph for explaining the operation of the embodiment shown in FIG. 21;
FIG. 23 is a block diagram for explaining another embodiment of the embodiment shown in FIG. 21;
FIG. 24 is a diagram for explaining the relationship between temperature and saturated vapor pressure.
[Explanation of symbols]
1 First seal jig 30F Zero point variable writing / reading means
2 Second seal jig 50 Humidity correction means
3 Temperature sensor 50A Seal error measuring means
4 Temperature difference measuring device 50B Seal error memory
5 Environmental temperature measurement means 50C Humidity correction coefficient acquisition means
14 core 50D humidity correction coefficient storage
15 piping 50E vapor pressure measuring means
16 Pressure sensor 50F Humidity correction value calculation means
16A Differential pressure gauge 60 Subtraction means
17, 17A, 17B solenoid valve 70 determination means
18 Three-way solenoid valve 80 Measurement jig
19 Pressure regulator 85 Negative pressure generator
20 Pneumatic pressure source 100 Leakage inspection device main body
Reference Signs List 30 drift correction means 101 central processing unit
30A Drift value acquisition means 102 ROM
30B Drift memory 103 RAM
30C drift write / read means 104 input port
30D linear approximation calculation means 105 output port
30E, 30E 'Zero point fluctuation value storage 200 Display

Claims

The opening of the test object is closed by a sealing jig. In this closed state, the air pressure is sealed inside the test object, and the change in the air pressure is measured. In the leak inspection device that determines that there is no leak when is small,
In the calibration mode, prepare a room temperature dried test object that has been dried without leakage to the test object, and set a predetermined temperature difference between the normal temperature dry test object and the seal jig, Applying air pressure to the room-temperature dried test object in a state where the predetermined temperature difference is given, measuring the amount of change in the air pressure as a drift value for each of the plurality of temperature differences, A drift value acquisition method for a leakage inspection device, wherein the drift value is stored in a drift storage device.

The opening of the object to be inspected is closed by a sealing jig, and in this closed state, air pressure is sealed in the object to be inspected and the reference tank. In a leak inspection device that determines whether
In the calibration mode, prepare a room temperature dried test object that has been dried without leakage to the test object, and set a predetermined temperature difference between the normal temperature dry test object and the seal jig, In a state where the predetermined temperature difference is given, air is sealed in the room temperature dried test object and the reference tank, and the fluctuation amount of the pressure difference is measured as a drift value for each of a plurality of temperature differences, A drift value acquisition method for a leak inspection device, wherein drift values of a plurality of temperature differences are stored in a drift storage device.

3. A leak inspection apparatus according to claim 1, wherein the drift storage device stores a drift value corresponding to a temperature difference between the test object and the seal jig in the drift storage device.
In the calibration mode, a room-temperature-dried test object that has been dried without leakage is prepared, and a temperature difference between the normal-temperature-dry test object and the sealing jig is measured. The drift value is derived from the drift storage device, and the air temperature is applied to the room-temperature dried test object to measure the drift value and the environmental temperature. A method for obtaining a zero point fluctuation value of a leakage inspection device, wherein a deviation is obtained and the deviation value is stored as a zero point fluctuation value corresponding to the measured environmental temperature in a zero point fluctuation storage device.

3. The leak inspection apparatus according to claim 1, wherein the drift storage device stores a drift value corresponding to a temperature difference between the test object and the sealing jig in the drift storage device. ,
In the calibration mode, prepare a dried room-temperature-dried test object whose leakage is unknown or not, and reduce the temperature difference between the dry room-temperature-dried test object whose leakage is unknown and the sealing jig to zero. In this setting state, apply a pneumatic pressure to the test object in this setting state, measure the provisional drift value and the environmental temperature, and measure the pressure change due to only leakage at a time that has elapsed longer than the drift measurement timing. This pressure change is subtracted from the tentative drift value to obtain a true drift value, and a deviation between the obtained drift value and a drift value stored in the drift storage device at an address corresponding to zero temperature difference is obtained. Storing the deviation value as a zero-point fluctuation value corresponding to the measured environmental temperature in a zero-point fluctuation storage device.

The method according to claim 3 or 4, wherein
A zero point fluctuation value obtained by the zero point fluctuation value obtaining method is obtained for each of a plurality of environmental temperatures, and the zero point fluctuation values obtained for each of the environmental temperatures are stored in a zero point fluctuation value storage. How to get zero point fluctuation value.

The opening of the object to be inspected is closed by a sealing jig, air pressure is applied to the inside of the object to be inspected in this closed state, and the amount of change in the air pressure inside the object to be inspected after a predetermined time has elapsed is measured. In the method of obtaining a humidity correction coefficient of the leak inspection device, which determines that there is no leakage when the amount of decrease in air pressure is large and that there is no leakage when the amount of decrease in air pressure is small,
In the calibration mode, prepare a room-temperature-dried test object without leakage, close the opening of the room-temperature-dried test object with a sealing jig, and change the pressure inside the test object after a predetermined time elapses in the closed state. Measuring the value as a seal error value ΔP ₀ by a seal jig;
Applying air pressure to the room-temperature dried test object, and measuring a pressure change value as a drift value ΔP ₀₁ during a predetermined time after the application of the air pressure;
A process of attaching a water drop to the inner surface of the room temperature dried test object and converting the room temperature dried test object to a normal temperature wet test object,
A process of closing the opening of the room-temperature wet test object with the seal jig and measuring a pressure change value during a predetermined time as a vapor pressure ΔP ₁ ;
A process of applying air pressure to the room-temperature wet test object and measuring an air pressure change value during a predetermined time after the application of the air pressure as a drift value ΔP ₁₁ of the wet test object;
A process of obtaining a humidity correction coefficient k from each of the measured values by k = (ΔP ₁₁ −ΔP ₀₁ ) / (ΔP ₁ −ΔP ₀ );
Storing the seal error value ΔP ₀ and the humidity correction coefficient k in a storage device;
And a method for obtaining a humidity correction coefficient of the leak inspection apparatus.

The opening of the object to be inspected is closed by a sealing jig, and air pressure is applied to the object to be inspected and the reference tank in the closed state, and the object to be inspected leaks depending on whether or not a pressure difference occurs between the two. In the method for obtaining a humidity correction coefficient of the leak inspection device for determining whether or not
In the calibration mode, a room-temperature-dried test object having no leakage is prepared, and the opening of the room-temperature-dry test object is closed with a sealing jig. Measuring a differential pressure value generated between the reference tank and a reference tank as a seal error value ΔP ₀ by a seal jig;
A process of applying air pressure to the room-temperature dried test object and the reference tank, and measuring a differential pressure value generated during a predetermined time after the application of the air pressure as a drift value ΔP ₀₁ ;
A process of attaching a water drop to the inner surface of the room temperature dried test object and converting the room temperature dried test object to a normal temperature wet test object,
Closing the opening of the room-temperature wet test object with the seal jig and measuring a change value of the differential pressure as a vapor pressure ΔP ₁ during a predetermined time;
A step of applying air pressure to the room temperature wet test object and the reference tank, and measuring the differential pressure change value as a drift value ΔP ₁₁ of the wet test object during a predetermined time after the application of the air pressure;
A process of obtaining a humidity correction coefficient k from each of the measured values by k = (ΔP ₁₁ −ΔP ₀₁ ) / (ΔP ₁ −ΔP ₀ );
Storing the seal error value ΔP ₀ and the humidity correction coefficient k in a storage device;
And a method for obtaining a humidity correction coefficient of the leak inspection apparatus.

A humidity correction method for a leak inspection device that stores a seal error value ΔP ₀ and a humidity correction coefficient k according to any one of the humidity correction coefficient acquisition methods for a leak inspection device according to claim 6 or 7.
In the inspection mode, the opening of the test object is closed by a sealing jig, and in this closed state, the pressure change value inside the test object or the differential pressure value generated between the test object and the reference tank is ΔP _X , The humidity correction value M is calculated by M = (ΔP _X −ΔP ₀ ) k, and the humidity correction value M is removed from the drift value generated at the time of the leak inspection to perform the humidity correction. Humidity correction method for leak inspection equipment.

A drift value corresponding to a temperature difference between an object to be inspected and a sealing jig is stored in a drift storage device by the drift value acquiring method of the leak inspection device according to claim 1, and the humidity correction of the leak inspection device according to claim 6. 3. The method of claim 1, wherein the seal error value ΔP ₀ and the humidity correction coefficient k are stored by a coefficient obtaining method. A leak test for a leak test apparatus which stores a drift value corresponding to a temperature difference between components and a seal error value ΔP ₀ and a humidity correction coefficient k by the method for obtaining a humidity correction coefficient for a leak test apparatus according to claim 7. In any of the methods,
In the inspection mode, a temperature difference between the test object and the seal jig is measured, a drift correction value corresponding to the temperature difference is read out from the drift storage device, and the drift value is calculated based on the air pressure sealed in the test object. By subtracting from the change amount, removing the drift component generated at the time of leakage inspection, sealing the opening of the inspection object with a sealing jig under an atmosphere of atmospheric pressure, until a predetermined time has elapsed from the sealing state. A pressure change value ΔP _X is measured, and a value (ΔP _X −ΔP ₀ ) obtained by subtracting the seal error value ΔP ₀ from the pressure change value ΔP _X is multiplied by the humidity correction coefficient k to obtain a humidity correction value M in the inspection mode. Is obtained by M = (ΔP _X −ΔP ₀ ) k, the humidity correction value M is subtracted from the variation of the air pressure from which the drift component has been removed, and the subtraction result is compared with a determination value for determining the presence or absence of leakage. thing A leak inspection method characterized by the following.

A. A sealing jig for closing the opening of the test object,
B. A temperature sensor for measuring a temperature difference between the seal jig and the test object,
C. A pressure sensor for measuring a change in air pressure inside the test object,
D. Drift value acquisition means for acquiring, as a drift value, a pressure change generated inside the room temperature dried test object for each temperature difference between the room temperature dried test object having no leakage and the seal jig in the calibration mode,
E. FIG. A drift storage device for storing the drift value for each of the temperature differences acquired by the drift value acquiring means,
F. In the calibration mode, the opening of the room-temperature dried test object without leakage is closed with the sealing jig under the atmospheric pressure environment, and the sealing error value ΔP ₀ is measured from the pressure change measured by the pressure sensor in the closed state. Sealing error measuring means to be
G. FIG. A seal error storage for storing the seal error value ΔP ₀ measured by the seal error measuring means,
H. The opening of the free cold wet test subject of leakage in the calibration mode closed by the sealing jig in an environment of atmospheric pressure, the pressure change value [Delta] P ₁ measured by the pressure sensor in its closed state, the normal temperature dried The air pressure is applied to the test object, the pressure change value ΔP ₀₁ inside the room temperature dried test object generated during a predetermined time elapses, and the air pressure is applied to the normal temperature wet test object with no leakage, The pressure change value ΔP ₁₁ inside the room-temperature wet test object, which is generated during the passage of time, is measured, and the humidity correction coefficient k is k = (k) based on the measurement result and the seal error value ΔP _0. Humidity correction coefficient obtaining means obtained by ΔP ₁₁ −ΔP ₀₁ ) / (ΔP ₁ −ΔP ₀ );
I. A humidity correction coefficient storage for storing the humidity correction coefficient k obtained by the humidity correction coefficient obtaining means;
J. In the inspection mode, drift writing / reading means for reading a drift value corresponding to a temperature difference between the test object and the seal jig measured by the temperature sensor from the drift storage,
K. In the inspection mode, the opening of the object to be inspected is closed by the seal jig under the environment of the atmospheric pressure, and a vapor pressure measuring means for humidity correction for measuring a pressure change inside the object to be inspected during the closing period. ,
L. The humidity for obtaining the humidity correction value M by subtracting the seal error value ΔP ₀ from the measurement value ΔP _X measured by the vapor pressure measuring means and multiplying the subtraction value (ΔP _X −ΔP ₀ ) by the humidity correction coefficient k. Correction value calculating means,
M. In the inspection mode, subtraction means for subtracting the drift value read by the drift writing and reading means and the humidity correction value M from the amount of change in air pressure contained in the inspection object, and performing drift correction and humidity correction,
N. Determining means for comparing the result of the subtraction with the set value with the set value to determine whether or not the test object has leaked;
A leak inspection device characterized by comprising:

A. A sealing jig for closing the opening of the test object,
B. A temperature sensor for measuring a temperature difference between the seal jig and the test object,
C. A differential pressure sensor that measures a change in differential pressure generated between the test object and the reference tank,
D. A drift value for acquiring a change in differential pressure generated between the cold-dried test object and the reference tank as a drift value for each temperature difference between the cold-dried test object and the sealing jig without leakage in the calibration mode. Acquisition means;
E. FIG. A drift storage device for storing the drift value for each of the temperature differences acquired by the drift value acquiring means,
F. In the calibration mode, the opening of the room-temperature dried test object without leakage is closed by the seal jig under the atmospheric pressure environment, and the sealing error value ΔP _{0 is obtained} from the differential pressure change measured by the differential pressure sensor in the closed state. Seal error measuring means for measuring the
G. FIG. A seal error storage for storing the seal error value ΔP ₀ measured by the seal error measuring means,
H. In the calibration mode, the opening of the room-temperature wet inspection object having no leakage is closed with the seal jig under the environment of the atmospheric pressure, and the differential pressure change value ΔP ₁ measured by the differential pressure sensor in the closed state, and the air pressure applied to air drying device under test and the reference tank, the difference between pressure change value [Delta] P ₀₁ between the air drying device under test and the reference tank which occurs during a predetermined time has elapsed, no leakage cold wet An air pressure is applied to the test object, and during a predetermined time, the differential pressure change value ΔP ₁₁ between the room temperature wet test object and the reference tank is measured, and the measurement result and the seal error value ΔP are measured. ₀ and humidity correction coefficient acquisition means for obtaining by the humidity correction factor _{_{k k = (ΔP 11 -ΔP 01}} ) / (ΔP 1 -ΔP 0) by a,
I. A humidity correction coefficient storage for storing the humidity correction coefficient k obtained by the humidity correction coefficient obtaining means;
J. In the inspection mode, drift writing / reading means for reading a drift value corresponding to a temperature difference between the test object and the seal jig measured by the temperature sensor from the drift storage,
K. In the inspection mode, the opening of the object to be inspected is closed by the seal jig under the environment of the atmospheric pressure, and a vapor pressure measuring means for humidity correction for measuring a pressure change inside the object to be inspected during the closing period. ,
L. The humidity for obtaining the humidity correction value M by subtracting the seal error value ΔP ₀ from the measurement value ΔP _X measured by the vapor pressure measuring means and multiplying the subtraction value (ΔP _X −ΔP ₀ ) by the humidity correction coefficient k. Correction value calculating means,
M. In the inspection mode, subtraction means for subtracting the drift value read by the drift writing and reading means and the humidity correction value M from the amount of change in air pressure contained in the inspection object, and performing drift correction and humidity correction,
N. Determining means for comparing the result of the subtraction with the set value with the set value to determine whether or not the test object has leaked;
A leak inspection device characterized by comprising:

The opening of the object to be inspected is closed by a sealing jig, air pressure is applied to the inside of the object to be inspected in this closed state, and the amount of change in the air pressure inside the object to be inspected after a predetermined time has elapsed is measured. It is determined that there is leakage when the amount of decrease in air pressure is large, and that there is no leakage when the amount of decrease in air pressure is small.The opening of the leak inspection device or the object to be inspected is closed by a sealing jig. Applying air pressure, in any of the humidity correction coefficient acquisition method of the leak inspection device to determine whether there is a leak in the test object by whether a pressure difference occurs between the two,
In the calibration mode, a room-temperature-dried test object without leakage is prepared, and a measuring jig for forming a closed space on the outer surface of the room-temperature-dried test object is attached via a seal jig. A step of closing the closed space for a predetermined time, and measuring a pressure change value after a predetermined time has passed in the closed state as a seal error value ΔP ₀ by a sealing jig;
Applying air pressure to the room-temperature dried test object, and measuring a pressure change value as a drift value ΔP ₀₁ during a predetermined time after the application of the air pressure;
A step of uniformly attaching water droplets to the inner surface and the outer surface of the room temperature dried test object facing the space formed by the measurement jig, and converting the room temperature dried test object to a normal temperature wet test object;
Covering the wet part of the room-temperature wet test object with the measuring jig and covering the wet part, and measuring a pressure change value as a vapor pressure ΔP ₁ during a lapse of a predetermined time;
A process of applying air pressure to the room-temperature wet test object and measuring an air pressure change value during a predetermined time after the application of the air pressure as a drift value ΔP ₁₁ of the wet test object;
A process of obtaining a humidity correction coefficient k from each of the measured values by k = (ΔP ₁₁ −ΔP ₀₁ ) / (ΔP ₁ −ΔP ₀ );
Storing the seal error value ΔP ₀ and the humidity correction coefficient k in a storage device;
And a method for obtaining a humidity correction coefficient of the leak inspection apparatus.

A humidity correction method for a leak inspection device, wherein a seal error value ΔP ₀ and a humidity correction coefficient k are stored by the method for obtaining a humidity correction coefficient for a leak inspection device according to claim 12.
In the inspection mode, a part of the outer surface of the object to be inspected is covered with the measurement jig to form a closed space, and when a pressure change value in the closed space during a predetermined time elapses is measured as ΔP _X , the humidity is measured. A humidity correction of a leak inspection apparatus, wherein a correction value M is calculated by M = (ΔP _X −ΔP ₀ ) k, and the humidity correction is performed by removing the humidity correction value M from a drift value generated during a leak inspection. Method.

A drift value corresponding to a temperature difference between an object to be inspected and a sealing jig is stored in a drift storage device by the drift value acquiring method for a leak inspection device according to claim 1, and humidity correction of the leak inspection device according to claim 12. 3. The method of claim 1, wherein the seal error value ΔP ₀ and the humidity correction coefficient k are stored by a coefficient obtaining method. A leak test of a leak test apparatus which stores a drift value corresponding to a temperature difference between components and a seal error value ΔP ₀ and a humidity correction coefficient k by the method of acquiring a humidity correction coefficient of the leak test apparatus according to claim 12. In any of the methods,
In the inspection mode, a temperature difference between the test object and the seal jig is measured, a drift correction value corresponding to the temperature difference is read out from the drift storage device, and the drift value is calculated based on the air pressure sealed in the test object. Subtract from the change amount, remove the drift component generated at the time of leakage inspection, cover part of the outer surface of the object to be inspected with the above measurement jig, close it, seal it under an atmosphere of atmospheric pressure, from the sealed state The pressure change value ΔP _X up to the time when a predetermined time has elapsed is measured, and a value (ΔP _X −ΔP ₀ ) obtained by subtracting the seal error value ΔP ₀ from the pressure change value ΔP _X is multiplied by the humidity correction coefficient k. The humidity correction value M in the inspection mode is obtained by M = (ΔP _X −ΔP ₀ ) k, and the humidity correction value M is subtracted from the change in air pressure from which the drift component has been removed. Judgment A leakage inspection method characterized by comparing with a judgment value to be performed.

A. A sealing jig for closing the opening of the test object,
B. A temperature sensor for measuring a temperature difference between the seal jig and the test object,
C. A pressure sensor that measures a change in air pressure inside the test object or a pressure difference generated between the test object and the reference tank,
D. Drift value acquisition means for acquiring, as a drift value, a pressure change generated inside the room temperature dried test object for each temperature difference between the room temperature dried test object having no leakage and the seal jig in the calibration mode,
E. FIG. A drift storage device for storing the drift value for each of the temperature differences acquired by the drift value acquiring means,
F. A measurement jig that is attached to the outside of the room-temperature dried inspection object without leakage in the calibration mode and forms a space closed by the concave portion,
G. FIG. Sealing error measuring means for closing a space formed by the measuring jig, and measuring a sealing error value ΔP ₀ from a pressure change measured by the vapor pressure measuring pressure sensor in the closed state;
H. A seal error storage for storing the seal error value ΔP ₀ measured by the seal error measuring means,
I. In the calibration mode, the room-temperature wet test object having no leakage is closed by the measurement jig under the environment of the atmospheric pressure, and in the closed state, the pressure change value ΔP ₁ measured by the vapor pressure measurement pressure sensor; Air pressure is applied to the room temperature dried test object, and a pressure change value ΔP ₀₁ inside the room temperature dried test object generated during a predetermined time elapses, and air pressure is applied to the room temperature wet test object, and a predetermined value is applied. The pressure change value ΔP ₁₁ inside the room temperature wet test object, which is generated during the passage of time, is measured, and the humidity correction coefficient k is k = (k) based on the measurement result and the seal error value ΔP _0. Humidity correction coefficient obtaining means obtained by ΔP ₁₁ −ΔP ₀₁ ) / (ΔP ₁ −ΔP ₀ ),
J. A humidity correction coefficient storage for storing the humidity correction coefficient k obtained by the humidity correction coefficient obtaining means;
K. In the inspection mode, drift writing / reading means for reading a drift value corresponding to a temperature difference between the test object and the seal jig measured by the temperature sensor from the drift storage,
L. In the inspection mode, a space formed by the measurement jig is closed under an atmosphere of atmospheric pressure, and a vapor pressure measurement unit for humidity correction for measuring a pressure change inside the space during the closing period,
M. The humidity for obtaining the humidity correction value M by subtracting the seal error value ΔP ₀ from the measurement value ΔP _X measured by the vapor pressure measuring means and multiplying the subtraction value (ΔP _X −ΔP ₀ ) by the humidity correction coefficient k. Correction value calculating means,
N. In the inspection mode, subtraction means for subtracting the drift value read by the drift writing and reading means and the humidity correction value M from the amount of change in air pressure contained in the inspection object, and performing drift correction and humidity correction,
O. Determining means for comparing the result of the subtraction with the set value with the set value to determine whether or not the test object has leaked;
A leak inspection device characterized by comprising:

The opening of the object to be inspected is closed by a sealing jig, air pressure is applied to the inside of the object to be inspected in this closed state, and the amount of change in the air pressure inside the object to be inspected after a predetermined time has elapsed is measured. It is determined that there is leakage when the amount of decrease in air pressure is large, and that there is no leakage when the amount of decrease in air pressure is small.The opening of the leak inspection device or the object to be inspected is closed by a sealing jig. Applying air pressure, in any of the humidity correction coefficient acquisition method of the leak inspection device to determine whether there is a leak in the test object by whether a pressure difference occurs between the two,
Providing a free air drying device under test of leakage in the calibration mode, the normal temperature dried air pressure is applied to the device under test, measured as the drift value [Delta] P ₀₁ the pressure change value during a predetermined time after the application of air pressure has elapsed Process
An outer surface of the room temperature dried test object, and a process of uniformly attaching water droplets to the inner surface of the room temperature dried test object and converting the room temperature dried test object to a room temperature wet test object,
A covered part is formed by covering a wet part of the room-temperature wet test object with a measuring jig, a predetermined negative pressure is applied to the closed space, and the closed part is closed for a predetermined time after the application of the negative pressure. A process of measuring a pressure change value in the space as a vapor pressure ΔP ₁ ;
A process of applying air pressure to the room-temperature wet test object and measuring an air pressure change value during a predetermined time after the application of the air pressure as a drift value ΔP ₁₁ of the wet test object;
A process of obtaining a humidity correction coefficient k from each of the measured values according to k = (ΔP ₁₁ −ΔP ₀₁ ) / ΔP ₁ ,
Storing the humidity correction coefficient k in a storage device;
And a method for obtaining a humidity correction coefficient of the leak inspection apparatus.

A humidity correction method for a leak inspection device in which a humidity correction coefficient k is stored by the humidity correction coefficient acquisition method for a leak inspection device according to claim 16,
If a portion of the outer surface of the object to be inspected is a pressure variation value of the closed space while forming a closed space covered by the measurement jig, the predetermined time elapses as [Delta] P _X in the inspection mode, humidity A humidity correction method for a leak inspection apparatus, wherein a correction value M is calculated by M = ΔP _X · k, and the humidity correction value M is removed from a drift value generated during a leak test to perform humidity correction.

The drift value corresponding to the temperature difference between the test object and the seal jig is stored in the drift storage device by the drift value acquiring method of the leak inspection device according to claim 1, and the humidity correction of the leak inspection device according to claim 16 is performed. According to the leak inspection method of the leak inspection device storing the humidity correction coefficient k by the coefficient acquisition method or the drift value acquisition method of the leakage inspection device according to claim 2, the drift storage device corresponds to the temperature difference between the test object and the sealing jig. In any one of the leak inspection methods of a leak inspection device that stores the corrected drift value and stores a humidity correction coefficient k by the humidity correction coefficient acquisition method of the leak inspection device according to claim 16,
In the inspection mode, a temperature difference between the test object and the seal jig is measured, a drift correction value corresponding to the temperature difference is read out from the drift storage device, and the drift value is calculated based on the air pressure sealed in the test object. Subtract from the amount of change, remove the drift component generated at the time of leakage inspection, seal the closed space formed by the test object and the measuring jig under a negative pressure environment, and when a predetermined time has elapsed from the sealed state The pressure change value ΔP _X in the closed space up to the above is measured, and the pressure change value ΔP _X is multiplied by the humidity correction coefficient k to obtain a humidity correction value M in the inspection mode by M = ΔP _X · k. A leak inspection method, wherein a humidity correction value M is subtracted from an amount of change in air pressure from which the drift component has been removed, and the result of the subtraction is compared with a determination value for determining the presence or absence of a leak.

A. A sealing jig for closing the opening of the test object,
B. A temperature sensor for measuring a temperature difference between the seal jig and the test object,
C. A pressure sensor that measures a change in air pressure inside the test object or a pressure difference generated between the test object and the reference tank,
D. Drift value acquisition means for acquiring, as a drift value, a pressure change generated inside the room temperature dried test object for each temperature difference between the room temperature dried test object having no leakage and the seal jig in the calibration mode,
E. FIG. A drift storage device for storing the drift value for each of the temperature differences acquired by the drift value acquiring means,
F. A measurement jig that is attached to the outside of the room-temperature dried inspection object without leakage in the calibration mode and forms a space closed by the concave portion,
G. FIG. In the calibration mode, a part of the outer surface of the room-temperature wet inspection object having no leakage is covered with the measurement jig, and a negative pressure is applied to the closed space formed by the measurement jig. A pressure change value ΔP ₁ measured by the vapor pressure measuring pressure sensor during a predetermined time and an air pressure applied to the room temperature drying test object, and the room temperature drying generated during a predetermined time elapses. The pressure change value ΔP ₀₁ inside the test object and the pressure change value ΔP ₁₁ inside the normal temperature wet test object generated during the lapse of a predetermined time by applying air pressure to the normal temperature test object are calculated. A humidity correction coefficient acquisition unit that measures each of them and obtains a humidity correction coefficient k from these measurement results by k = (ΔP ₁₁ −ΔP ₀₁ ) / ΔP ₁ ;
H. A humidity correction coefficient storage for storing the humidity correction coefficient k obtained by the humidity correction coefficient obtaining means;
I. In the inspection mode, drift writing / reading means for reading a drift value corresponding to a temperature difference between the test object and the seal jig measured by the temperature sensor from the drift storage,
J. In the inspection mode, a negative pressure is applied to the space formed by the measuring jig, and a vapor pressure measuring unit for humidity correction for measuring a pressure change inside the space in the negative pressure applied state,
K. And humidity correction value calculating means for determining the humidity correction value M to the measured value [Delta] P _X measured by vapor pressure measurement means by multiplying the humidity correction factor k,
L. In the inspection mode, subtraction means for subtracting the drift value read by the drift writing and reading means and the humidity correction value M from the amount of change in air pressure contained in the inspection object, and performing drift correction and humidity correction,
M. Determining means for comparing the result of the subtraction with the set value with the set value to determine whether or not the test object has leaked;
A leak inspection device characterized by comprising:

20. The leak inspection apparatus according to claim 10, wherein a drift value corresponding to a temperature difference between the test object and a seal jig measured by the temperature sensor in an inspection mode is stored in the drift inspection apparatus. In the case where the drift value does not exist, a linear approximation calculating means for calculating a drift value corresponding to a corresponding temperature difference by linear approximation from a plurality of drift values stored in the drift storage device is provided. Leak inspection equipment.