JP2021067633A - Method of measuring gas concentration in packaging bag - Google Patents

Method of measuring gas concentration in packaging bag Download PDF

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JP2021067633A
JP2021067633A JP2019195096A JP2019195096A JP2021067633A JP 2021067633 A JP2021067633 A JP 2021067633A JP 2019195096 A JP2019195096 A JP 2019195096A JP 2019195096 A JP2019195096 A JP 2019195096A JP 2021067633 A JP2021067633 A JP 2021067633A
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laser
packaging bag
gas concentration
gas
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雅志 大島
Masashi Oshima
雅志 大島
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General Packer Co Ltd
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Abstract

To provide a gas concentration measurement method which improves measurement accuracy by increasing the optical path length of a laser beam to a fixed length.SOLUTION: A gas concentration measurement method using a laser-type gas concentration meter is provided, the method comprising letting a laser beam of a specific wavelength pass through a gas-replaced, sealed packaging bag B, and measuring gas concentration of a specific gas remaining in the packaging bag B based on an absorption spectrum of the specific wavelength that changes before and after passing through the packaging bag B, the laser-type gas concentration meter comprising a laser generator 11 for emitting the laser beam and a laser receiver 12 for receiving the laser beam, where the laser beam emitted from the laser generator obliquely passes through the packaging bag B sandwiched between a first guide 30 and a second guide 31 before being incident on the laser receiver.SELECTED DRAWING: Figure 1

Description

本発明は、ガス置換されて密封された包装袋内に残存する特定ガスのガス濃度を測定するガス濃度測定方法に関するものである。 The present invention relates to a gas concentration measuring method for measuring the gas concentration of a specific gas remaining in a package bag that has been gas-replaced and sealed.

従来、包装工程において、被包装物の保存期間又は賞味期間を縮めるおそれのある特定の酸化原因ガスを含んだ包装袋内の空気を除去して、不活性ガス、たとえば窒素、二酸化炭素等にガス置換してから密封するガス置換包装が行われている。これによって、包装袋内部の酸化原因ガスは除去され、被包装物、特に食品は、長期の保存期間、賞味期間を確保することができる。
そして、ガス置換包装後の検査工程において、酸化原因ガス、特に酸素の濃度が既定値以下であるかどうか検査が行われている。
しかしながら、現在主流である酸素濃度の測定方法は、サンプルとして任意に選択した包装袋に注射針を刺し、包装袋内から吸引した少量のガスの組成を検査する抜き取り検査である。当該抜き取り検査では、注射痕が形成された包装袋は廃棄しなければならない。また、検査精度を上げるためにサンプル数を増やすと検査時間が長くなり、増加する廃棄量によって経済的、時間的損失が増大する不都合があった。 Conventionally, in the packaging process, the air in the packaging bag containing a specific oxidation-causing gas that may shorten the storage period or the taste period of the packaged object is removed, and the gas is converted into an inert gas such as nitrogen or carbon dioxide. Gas replacement packaging is performed after replacement and sealing. As a result, the oxidation-causing gas inside the packaging bag is removed, and the packaged object, particularly the food, can secure a long storage period and a shelf life.
Then, in the inspection step after gas replacement packaging, inspection is performed to see if the concentration of the oxidation-causing gas, particularly oxygen, is equal to or less than the predetermined value.
However, the current mainstream method for measuring oxygen concentration is a sampling test in which an injection needle is inserted into a packaging bag arbitrarily selected as a sample and the composition of a small amount of gas sucked from the packaging bag is inspected. In the sampling inspection, the packaging bag on which the injection mark is formed must be discarded. Further, if the number of samples is increased in order to improve the inspection accuracy, the inspection time becomes long, and there is a disadvantage that the economic and time loss increases due to the increased amount of waste.

これに対し、本願出願人は、包装袋を損傷することなく内部の特定ガスの濃度を測定可能なガス濃度測定装置を開発した。
特開２０１０−１０７１９７に開示されている包装袋のガス濃度測定装置１は、図７に示すように、発信器を有するレーザー発生部２と、当該レーザー発生部２に連接し、レーザー光が射出される主ヘッド３、並びに受信器を有するレーザー受光部４と、当該レーザ受光部４に連接し、レーザー光が入射される副ヘッド５とからなる。相対的に接近及び離隔自在に設けられた主ヘッド３と副ヘッド５は、、一対のグリップ６，６に把持された検査対象の包装袋Ｂを挟んで、主ヘッド３に対して副ヘッド５が正対するように配置されている。これによって、主ヘッド３から副ヘッド５へ最短距離でレーザー光が包装袋を透過することができ、包装袋内に残留している酸素等の特定ガスの濃度を測定する際に、包装袋の全数について当該包装袋を一切損傷することなく迅速に測定することができるようになった。 On the other hand, the applicant of the present application has developed a gas concentration measuring device capable of measuring the concentration of a specific gas inside without damaging the packaging bag.
As shown in FIG. 7, the packaging bag gas concentration measuring device 1 disclosed in Japanese Patent Application Laid-Open No. 2010-107197 is connected to a laser generating unit 2 having a transmitter and the laser generating unit 2, and a laser beam is emitted. It is composed of a main head 3 to be generated, a laser light receiving unit 4 having a receiver, and a sub head 5 which is connected to the laser light receiving unit 4 and receives laser light. The main head 3 and the sub-head 5 provided so as to be relatively close to each other and separated from each other sandwich the packaging bag B to be inspected held by the pair of grips 6 and 6, and the sub-head 5 is relative to the main head 3. Are arranged so that they face each other. As a result, the laser beam can pass through the packaging bag from the main head 3 to the sub head 5 at the shortest distance, and when measuring the concentration of a specific gas such as oxygen remaining in the packaging bag, the packaging bag It has become possible to quickly measure all of the packaging bags without damaging the packaging bags.

特開２０１０−１０７１９７号公報JP-A-2010-107197

しかしながら、上記のガス濃度測定装置１は、包装袋Ｂに対してレーザー光を透過させるとき、包装袋Ｂ内に封じられる気体の量が多少変化しても光路長の変化が小さくなるように主ヘッド３と副ヘッド５を正対させて、光路長を一定にしている。これが、測定対象の包装袋Ｂ内の気体の状態を検査するために十分な光路長を確保することの妨げとなり、上記のガス濃度測定装置１は、測定対象である特定ガスのガス濃度について測定誤差が生じやすい状態であった。 However, in the gas concentration measuring device 1 described above, when the laser beam is transmitted through the packaging bag B, the change in the optical path length is mainly reduced even if the amount of gas sealed in the packaging bag B changes slightly. The head 3 and the sub head 5 face each other to keep the optical path length constant. This hinders securing a sufficient optical path length for inspecting the state of the gas in the packaging bag B to be measured, and the gas concentration measuring device 1 described above measures the gas concentration of the specific gas to be measured. It was in a state where errors were likely to occur.

したがって、本発明が解決しようとする課題は、レーザー光の光路長を長く伸ばすと共に当該光路長が一定になるようにして、測定精度を向上させたガス濃度測定方法を提供することである。 Therefore, an object to be solved by the present invention is to provide a gas concentration measuring method in which the optical path length of the laser beam is extended and the optical path length is kept constant to improve the measurement accuracy.

請求項１に記載のガス濃度測定方法は、特定波長のレーザー光を、ガス置換されて密封された包装袋に透過させて、前記包装袋の透過前後で変化する特定波長の吸収スペクトルに基づいて前記包装袋の内部に残留している特定ガスのガス濃度を測定するようにしたレーザー式ガス濃度計を有するガス濃度測定方法であって、
前記レーザー光を発生するレーザー発生部と、
前記レーザー光を受光するレーザー受光部とを有し、
前記レーザー発生部から射出される前記レーザー光が、前記包装袋を斜めに透過して、前記レーザー受光部へ入射するようにしたことを特徴とする。 The gas concentration measuring method according to claim 1 is based on an absorption spectrum of a specific wavelength that changes before and after transmission of the packaging bag by transmitting a laser beam of a specific wavelength through a package bag that has been gas-substituted and sealed. A gas concentration measuring method having a laser gas densitometer for measuring the gas concentration of a specific gas remaining inside the packaging bag.
The laser generating part that generates the laser light and
It has a laser light receiving unit that receives the laser light.
The laser beam emitted from the laser generating portion is obliquely transmitted through the packaging bag and incident on the laser receiving portion.

請求項２に記載のガス濃度測定方法は、請求項１に記載の発明において、前記包装袋を挟んでレーザー発生部を袋の一側に配置するとともにレーザー受光部を包装袋の他側に配置したことを特徴とする。 The gas concentration measuring method according to claim 2 is the invention according to claim 1, wherein the laser generating portion is arranged on one side of the bag and the laser receiving portion is arranged on the other side of the packaging bag with the packaging bag interposed therebetween. It is characterized by having done it.

請求項３に記載のガス濃度測定方法は、前記レーザー発生部の上方又は下方に、前記レーザー受光部を配置したことを特徴とする。 The gas concentration measuring method according to claim 3 is characterized in that the laser receiving unit is arranged above or below the laser generating unit.

請求項４に記載のガス濃度測定方法は、前記レーザー発生部と前記レーザー受光部を同一高さに配置したことを特徴とする。 The gas concentration measuring method according to claim 4 is characterized in that the laser generating portion and the laser receiving portion are arranged at the same height.

請求項５に記載のガス濃度測定方法は、請求項３若しくは請求項４に記載の発明において、前記レーザー発生部と前記レーザー受光部を対角に配置したことを特徴とする。 The gas concentration measuring method according to claim 5 is characterized in that, in the invention according to claim 3 or 4, the laser generating portion and the laser receiving portion are arranged diagonally.

本発明に係るガス濃度測定方法によれば、レーザー発生部から射出されるレーザー光が包装袋を斜めに透過してレーザー受光部に入射するようにした。これによって、レーザー光の光路長を伸ばすことができるので、ガス濃度の測定精度を向上させることができる。
また、レーザー光を包装体に対して斜めに透過させるために、レーザー発生部とレーザー受光部の配置に特徴を有するようにした。具体的には、同一平面上で左右方向に対角に配され、また上下方向に対角に配され、さらにはレーザー発生部とレーザー受光部を頂点に含む直方体を想定したとき、当該直方体の対角線に沿って斜めにレーザー光が射出されるようにした。これによって、包装袋内の光路長を長くすることができ、ガス濃度測定の測定精度を向上させることができる。 According to the gas concentration measuring method according to the present invention, the laser light emitted from the laser generating portion is obliquely transmitted through the packaging bag and incident on the laser receiving portion. As a result, the optical path length of the laser beam can be extended, so that the measurement accuracy of the gas concentration can be improved.
Further, in order to transmit the laser light diagonally to the package, the arrangement of the laser generating portion and the laser receiving portion is characterized. Specifically, assuming a rectangular parallelepiped that is diagonally arranged in the left-right direction on the same plane, diagonally arranged in the vertical direction, and further includes a laser generating part and a laser receiving part at the apex, the rectangular parallelepiped The laser beam is emitted diagonally along the diagonal line. As a result, the optical path length in the packaging bag can be lengthened, and the measurement accuracy of the gas concentration measurement can be improved.

第１実施例に係るガス濃度測定方法に用いるガス濃度測定装置の構成の概略を示す平面図である。It is a top view which shows the outline of the structure of the gas concentration measuring apparatus used in the gas concentration measuring method which concerns on 1st Example. 第１実施例に係るガス濃度測定方法に用いるガス濃度測定装置の構成の概略を示すブロック図である。It is a block diagram which shows the outline of the structure of the gas concentration measuring apparatus used in the gas concentration measuring method which concerns on 1st Example. 第１実施例に係るガス濃度測定方法の原理を示す説明図である。It is explanatory drawing which shows the principle of the gas concentration measurement method which concerns on 1st Example. 第１実施例に係るガス濃度測定方法に用いるガス濃度測定装置の第１透過パターンの構成の概略を示す横断面図である。It is a cross-sectional view which shows the outline of the structure of the 1st transmission pattern of the gas concentration measuring apparatus used in the gas concentration measuring method which concerns on 1st Example. 第１実施例に係るガス濃度測定方法に用いるガス濃度測定装置の第２透過パターンの構成の概略を示す縦断面図である。It is a vertical cross-sectional view which shows the outline of the structure of the 2nd transmission pattern of the gas concentration measuring apparatus used in the gas concentration measuring method which concerns on 1st Example. 第１実施例に係るガス濃度測定方法に用いるガス濃度測定装置の第３透過パターンの構成の概略を示す斜視図である。It is a perspective view which shows the outline of the structure of the 3rd transmission pattern of the gas concentration measuring apparatus used in the gas concentration measuring method which concerns on 1st Example. 従来のガス濃度測定装置の構成の概略を示す平面図である。It is a top view which shows the outline of the structure of the conventional gas concentration measuring apparatus.

本発明に係るガス濃度測定方法の実施例を、添付した図面にしたがって説明する。
図１は本実施例に係るガス濃度測定方法に用いるガス濃度測定装置の構成の概略を示す説明図であって、図２は当該ガス濃度測定装置の構成の概略を示すブロック図である。 Examples of the gas concentration measuring method according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is an explanatory diagram showing an outline of the configuration of a gas concentration measuring device used in the gas concentration measuring method according to the present embodiment, and FIG. 2 is a block diagram showing an outline of the configuration of the gas concentration measuring device.

本実施例に係るガス濃度測定方法に用いるガス濃度測定装置１０は、図１に示すように、包装袋Ｂの内部に残留している特定ガスのガス濃度を測定する装置である。当該ガス濃度測定装置１０は、出荷前に包装袋を検査する検査場で設置されたり、また、包装に係る各種工程を有するロータリー式或いはピロー式等の包装機の検査工程を担うように当該包装機上に配置されている。本実施例においては、それらを踏まえて、ガス濃度測定装置１０について説明する。
残留している特定ガスとは、たとえば、酸素ガス（Ｏ２）である。大気雰囲気下で行われる包装機の包装工程では、被包装物を充填したとき、包装袋Ｂ内部に大気も充填される。大気に含まれている酸素ガスをはじめとした酸化原因ガスは、被包装物、特に食品類を酸化させて劣化させる原因となる。そのため、包装機には、被包装物を包装袋に充填する包装工程の後に、当該包装袋から大気を抜気して、不活性ガス、たとえば、窒素ガス（Ｎ２）、二酸化炭素ガス（ＣＯ２）に置換するガス置換（ガスパージ）工程が設けられている。
その後、ガス置換された包装袋Ｂ内部の酸素ガスの濃度を測定して、当該酸素ガスが基準値以下に収まっているかどうか検査するための装置が、本実施例に係るガス濃度測定装置である。当該ガス濃度検査において、酸素ガスのガス濃度が基準値以下に収まっている場合は、正常にガス置換が行われ、包装袋Ｂ内部は不活性ガスが充満しているので、被包装物の酸化を防止することができ、保存期間や賞味期間を延ばすことができる。一方、酸素ガスのガス濃度が基準値を超えている場合は、不良品と判定され、たとえば、包装機から不良と判定された包装袋Ｂが排出されるように構成されている。 As shown in FIG. 1, the gas concentration measuring device 10 used in the gas concentration measuring method according to the present embodiment is a device for measuring the gas concentration of a specific gas remaining inside the packaging bag B. The gas concentration measuring device 10 is installed at an inspection site for inspecting packaging bags before shipment, and is responsible for the inspection process of a rotary type or pillow type packaging machine having various processes related to packaging. It is located on the plane. In this embodiment, the gas concentration measuring device 10 will be described based on these.
The residual specific gas is, for example, oxygen gas (O 2 ). In the packaging process of the packaging machine performed in an air atmosphere, when the object to be packaged is filled, the inside of the packaging bag B is also filled with the air. Oxidation-causing gases such as oxygen gas contained in the atmosphere cause oxidation and deterioration of the packaged material, especially foods. Therefore, in the packaging machine, after the packaging process of filling the packaging bag with the object to be packaged, the air is evacuated from the packaging bag, and an inert gas such as nitrogen gas (N 2 ) or carbon dioxide gas (CO) is used. A gas replacement (gas purge) step for replacing 2) is provided.
After that, the device for measuring the concentration of the oxygen gas inside the gas-replaced packaging bag B and inspecting whether or not the oxygen gas is within the reference value is the gas concentration measuring device according to the present embodiment. .. In the gas concentration test, if the gas concentration of oxygen gas is below the standard value, gas replacement is performed normally, and the inside of the packaging bag B is filled with an inert gas, so that the packaged object is oxidized. Can be prevented, and the storage period and the best-before date can be extended. On the other hand, when the gas concentration of the oxygen gas exceeds the reference value, it is determined to be a defective product, and for example, the packaging bag B determined to be defective is discharged from the packaging machine.

本実施例に係るガス濃度測定装置１０は、図１に示すように、レーザー光を射出するレーザー発生部１１と、レーザー光を受光するレーザー受光部１２とを備えたレーザー式ガス濃度計と、包装袋Ｂを挟持可能に形成された相対するガイド３０，３１を有している。 As shown in FIG. 1, the gas concentration measuring device 10 according to the present embodiment includes a laser gas concentration meter including a laser generating unit 11 for emitting laser light and a laser receiving unit 12 for receiving laser light. It has opposing guides 30 and 31 formed so that the packaging bag B can be sandwiched.

レーザー式ガス濃度計は、波長可変半導体レーザー吸収分光法によって特定ガスを分析可能に形成されている。
ここで、波長可変半導体レーザー吸収分光法（Ｔｕｎａｂｌｅ Ｄｉｏｄｅ Ｌａｓｅｒ Ａｂｓｏｒｐｔｉｏｎ Ｓｐｅｃｔｒｏｓｃｏｐｙ：ＴＤＬＡＳ）とは、半導体レーザー素子から出力されたレーザー光に係る所定の入射光強度と、測定対象となる特定ガス含んだ気体を封じたセルを透過して、当該特定ガスに吸収された透過後のレーザー光に係る透過光強度とから透過率を求めて、透過率に基づくレーザー光の吸光度からガス濃度を測定する方法である。
特定ガスを含めて気体はそれぞれ固有の吸収波長帯を有し、当該吸収波長帯にはより強く光を吸収する波長に係る吸収線が複数本含まれていることが知られている。ＴＤＬＡＳは、出力するレーザー光の近赤外領域の波長を、測定対象となる特定ガスの複数本の吸収線のうち、一本の吸収線に係る特定波長に合致するように変調し、増幅するように構成されている。そして、セルの透過前後で変化する特定波長の吸収スペクトルに基づいてレーザー光の吸光度を求めてガス濃度を測定している。なお、本実施例において測定対象ガスは酸素ガスであって、当該測定対象ガスを封じるセルは包装袋である。 The laser gas densitometer is formed so that a specific gas can be analyzed by tunable semiconductor laser absorption spectroscopy.
Here, the wavelength variable semiconductor laser absorption spectrometry (TDLAS) is a predetermined incident light intensity related to the laser light output from the semiconductor laser element and a gas containing a specific gas to be measured. This is a method in which the transmittance is obtained from the transmitted light intensity of the transmitted laser light absorbed by the specific gas after passing through the sealed cell, and the gas concentration is measured from the absorbance of the laser light based on the transmittance. ..
It is known that each gas including a specific gas has a unique absorption wavelength band, and the absorption wavelength band includes a plurality of absorption lines related to wavelengths that absorb light more strongly. TDLAS modulates and amplifies the wavelength of the output laser light in the near-infrared region so as to match the specific wavelength of one absorption line among the plurality of absorption lines of the specific gas to be measured. It is configured as follows. Then, the gas concentration is measured by obtaining the absorbance of the laser beam based on the absorption spectrum of a specific wavelength that changes before and after the transmission of the cell. In this embodiment, the gas to be measured is oxygen gas, and the cell that seals the gas to be measured is a packaging bag.

レーザー発生部１１は、図２に示すように、レーザー光源１３と、当該光源から射出するレーザー光の波長を特定の波長に設定し、所定の光強度に調整する制御部１４とを有している。
レーザー光源１３は、波長が可変可能なダイオードからなる半導体レーザー素子を備え、近赤外領域のレーザー光を出力可能に形成されている。
制御部１４は、半導体レーザー素子から出力されるレーザー光の波長を測定対象の特定ガス固有の特定波長に調整して、レーザー光が所定の入射光強度で射出されるように増幅する制御を行うように形成されている。
ここで、本実施例に係るレーザー式ガス濃度計が測定する特定ガスは、酸素ガスである。当該酸素ガス固有の吸収波長帯は７６０ｎｍ帯であり、当該吸収波長帯に含まれる複数の吸収線のうち、一の吸収線に係る特定波長がレーザー光の出力波長として選択される。 As shown in FIG. 2, the laser generation unit 11 includes a laser light source 13 and a control unit 14 that sets the wavelength of the laser light emitted from the light source to a specific wavelength and adjusts the wavelength to a predetermined light intensity. There is.
The laser light source 13 includes a semiconductor laser element made of a diode having a variable wavelength, and is formed so as to be capable of outputting laser light in the near infrared region.
The control unit 14 adjusts the wavelength of the laser light output from the semiconductor laser element to a specific wavelength peculiar to the specific gas to be measured, and controls to amplify the laser light so that it is emitted at a predetermined incident light intensity. It is formed like this.
Here, the specific gas measured by the laser gas densitometer according to the present embodiment is oxygen gas. The absorption wavelength band peculiar to the oxygen gas is the 760 nm band, and among the plurality of absorption lines included in the absorption wavelength band, a specific wavelength related to one absorption line is selected as the output wavelength of the laser beam.

レーザー発生部１１は、第１ハウジング１５に内蔵されている。当該第１ハウジング１５は第１窓部１６を有している。第１窓部１６には、近赤外領域の光を通しやすいサファイヤガラスが嵌め込まれている。そして、レーザー発生部１１は、第１窓部１６を通じて第１ハウジング１５からレーザー光を射出するように形成されている。 The laser generator 11 is built in the first housing 15. The first housing 15 has a first window portion 16. A sapphire glass that easily allows light in the near infrared region to pass through is fitted in the first window portion 16. The laser generating portion 11 is formed so as to emit laser light from the first housing 15 through the first window portion 16.

第１ハウジング１５内は特定ガス、本実施例においては酸素ガスを除去するために、真空化またはガス置換（ガスパージ）をすることができるように形成されている。そのため、第１ハウジング１５内を真空で維持したり、或いは窒素ガス、又は二酸化炭素或いはこれらに類する不活性ガス類で満たすことができる。
これによって、レーザー光源１３から第１窓部１６を通じて射出するまでの間に、第１ハウジング１５内でレーザ光が特定ガスに吸収されることを防止することができるので、ガス濃度測定の精度を向上させることができる。 The inside of the first housing 15 is formed so that vacuuming or gas replacement (gas purging) can be performed in order to remove a specific gas, or oxygen gas in this embodiment. Therefore, the inside of the first housing 15 can be maintained in a vacuum, or can be filled with nitrogen gas, carbon dioxide, or an inert gas similar thereto.
As a result, it is possible to prevent the laser beam from being absorbed by the specific gas in the first housing 15 during the period from the laser light source 13 to the emission through the first window portion 16, so that the accuracy of gas concentration measurement can be improved. Can be improved.

レーザー受光部１２は、図２に示すように、包装袋を透過したレーザー光を受光する受光センサ２０と、当該受光センサ２０からの受光信号に基づいて、ガス濃度を測定する測定部２１とを有している。
受光センサ２０は、包装袋を透過したレーザー光の透過光強度を電気的な透過光信号に変換する素子、たとえば、フォトダイオードからなる。これによって、包装袋を透過したレーザー光の透過光強度を電気的に処理することができる。
測定部２１は、透過光強度に係る透過光信号と、レーザー発生部１１から出力されたレーザー光の入射光強度に係る入射光信号に基づいて透過率を計算し、当該透過率に基づいてレーザー光の特定ガスによる吸光度を求め、当該吸光度に基づいて包装袋内の特定ガスの濃度を測定するように形成されている。 As shown in FIG. 2, the laser light receiving unit 12 includes a light receiving sensor 20 that receives the laser light transmitted through the packaging bag and a measuring unit 21 that measures the gas concentration based on the light receiving signal from the light receiving sensor 20. Have.
The light receiving sensor 20 includes an element that converts the transmitted light intensity of the laser light transmitted through the packaging bag into an electrically transmitted light signal, for example, a photodiode. Thereby, the transmitted light intensity of the laser light transmitted through the packaging bag can be electrically processed.
The measuring unit 21 calculates the transmittance based on the transmitted light signal related to the transmitted light intensity and the incident light signal related to the incident light intensity of the laser light output from the laser generating unit 11, and the laser is based on the transmittance. It is formed so as to determine the absorbance of light by a specific gas and measure the concentration of the specific gas in the packaging bag based on the absorbance.

レーザー受光部１２は、第２ハウジング２２に内蔵されている。第２ハウジング２２は第２窓部２３を有している。第２窓部２３には、第１窓部１６と同様に、近赤外領域の光を通しやすいサファイヤガラスが嵌め込まれている。
これによって、レーザー受光部１２は、第２窓部２３を通じて包装袋を透過したレーザー光を受光するように形成されている。
第２ハウジング２２内もまた、第１ハウジングと同様に、真空化又は、ガス置換可能に形成されている。そのため、第２窓部２３を通じて入射されたレーザー光を受光センサ２０が受光するまでの間に、第２ハウジング２２内でレーザ光が特定ガスに吸収されることを防止することができるので、ガス濃度測定の精度を向上させることができる。 The laser light receiving unit 12 is built in the second housing 22. The second housing 22 has a second window portion 23. Similar to the first window portion 16, the second window portion 23 is fitted with sapphire glass that easily allows light in the near infrared region to pass through.
As a result, the laser light receiving portion 12 is formed so as to receive the laser light transmitted through the packaging bag through the second window portion 23.
The inside of the second housing 22 is also formed so as to be evacuated or gas-replaceable like the first housing. Therefore, it is possible to prevent the laser beam from being absorbed by the specific gas in the second housing 22 until the light receiving sensor 20 receives the laser beam incident through the second window portion 23. The accuracy of concentration measurement can be improved.

このように、レーザー式ガス濃度計は、図１及び図２に示すように、レーザー発生部１１から第１窓部１６を通じてレーザー光を射出し、当該レーザー光を測定対象の包装袋Ｂに透過させて、第２窓部２３を通じてレーザー受光部１２で包装袋Ｂを透過したレーザー光を受光するように構成されている。
そして、当該レーザー式ガス濃度計を有するガス濃度測定装置１０は、第１ガイド３０と第２ガイド３１で挟持して固定した包装袋Ｂを第１窓部１６から射出されたレーザー光が斜めに透過して第２窓部２３へ入射するように構成されている。 As described above, as shown in FIGS. 1 and 2, the laser gas densitometer emits laser light from the laser generating unit 11 through the first window unit 16 and transmits the laser light to the packaging bag B to be measured. The laser light receiving unit 12 is configured to receive the laser light transmitted through the packaging bag B through the second window unit 23.
Then, in the gas concentration measuring device 10 having the laser type gas densitometer, the laser beam emitted from the first window portion 16 obliquely emits the packaging bag B sandwiched and fixed between the first guide 30 and the second guide 31. It is configured to be transmitted and incident on the second window portion 23.

第１ガイド３０は、所定の位置に第１窓部１６が設けられた平板からなり、第２ガイド３１は、所定の位置に第２窓部２３が設けられた平板からなる。第１ガイド３０と第２ガイド３１は、互いに平行に対向するように形成されている。第１ガイド３０と第２ガイド３１は、相対的に接離自在に形成され、第１ガイド３０と第２ガイド３１との間に包装袋Ｂを挟持可能に形成されている。これによって、包装袋Ｂは、第１ガイド３０と第２ガイド３１の間に固定される。
さらに、第１ガイド３０と第２ガイド３１が包装袋Ｂを挟持したとき、当該包装袋Ｂに第１窓部１６と第２窓部２３が密着するように、第１ガイド３０上で第１窓部１６の位置を定め、当該第１窓部１６の位置に対して、包装袋Ｂをレーザー光が斜めに透過するように第２ガイド３１上で第２窓部２３の位置が定められる。
これによって、レーザー光を第１窓部１６から射出して、第２窓部２４へ入射させるとき、大気に含まれている特定ガスの影響を最小限に抑えることができ、より高精度に特定ガスの濃度を測定することができる。 The first guide 30 is composed of a flat plate having a first window portion 16 provided at a predetermined position, and the second guide 31 is composed of a flat plate provided with a second window portion 23 at a predetermined position. The first guide 30 and the second guide 31 are formed so as to face each other in parallel. The first guide 30 and the second guide 31 are formed so as to be relatively detachable, and the packaging bag B can be sandwiched between the first guide 30 and the second guide 31. As a result, the packaging bag B is fixed between the first guide 30 and the second guide 31.
Further, when the first guide 30 and the second guide 31 sandwich the packaging bag B, the first on the first guide 30 so that the first window portion 16 and the second window portion 23 are in close contact with the packaging bag B. The position of the window portion 16 is determined, and the position of the second window portion 23 is determined on the second guide 31 so that the laser beam is obliquely transmitted through the packaging bag B with respect to the position of the first window portion 16.
As a result, when the laser beam is emitted from the first window portion 16 and incident on the second window portion 24, the influence of the specific gas contained in the atmosphere can be minimized, and the laser light can be specified with higher accuracy. The concentration of gas can be measured.

第１窓部１６と第２窓部２３の位置は、第１窓部１６に対して第２窓部２３が正対しないように配置すれば良く、第１窓部１６から射出されるレーザ光が、包装袋Ｂを斜めに透過して第２窓部２３へ入射するように構成されている。
レーザ光が第１窓部１６から射出され、第２窓部２３へ入射するとき、当該レーザー光の第２ガイド３１面に対する入射角度θは、たとえば、図４に示すように、５度から８５度の間で任意に設定することができ、さらに第１反射面３０と第２反射面３１間の距離に基づいて光路長の計算を容易に行うことができる３０度又は６０度、或いは４５度が好ましい。入射角度が５度以下の場合、第１窓部１６と第２窓部２３が正対している従来の場合と光路長の差が大きくならないことから、誤差が生じやすくなるおそれがある。一方、入射角度が８５度以上の場合、包装袋Ｂを透過するレーザー光が特定ガスに吸収されるよりも散乱される割合が大きくなり、ガス濃度の測定で誤差が生じやすくなるおそれがある。 The positions of the first window portion 16 and the second window portion 23 may be arranged so that the second window portion 23 does not face the first window portion 16 and the laser light emitted from the first window portion 16. Is configured to penetrate the packaging bag B diagonally and enter the second window portion 23.
When the laser light is emitted from the first window portion 16 and is incident on the second window portion 23, the incident angle θ of the laser light with respect to the second guide 31 surface is, for example, 5 degrees to 85 as shown in FIG. The degree can be arbitrarily set, and the optical path length can be easily calculated based on the distance between the first reflecting surface 30 and the second reflecting surface 31. 30 degrees, 60 degrees, or 45 degrees. Is preferable. When the incident angle is 5 degrees or less, an error is likely to occur because the difference in the optical path length is not large compared to the conventional case where the first window portion 16 and the second window portion 23 face each other. On the other hand, when the incident angle is 85 degrees or more, the ratio of the laser light transmitted through the packaging bag B being absorbed by the specific gas is larger than that of being absorbed by the specific gas, and there is a possibility that an error is likely to occur in the measurement of the gas concentration.

ここで、波長可変半導体レーザー吸収分光法（ＴＤＬＡＳ）は、ランバート・ベールの法則に基づいてガス濃度を測定するものである。ランバート・ベールの法則とは、図３に示すように、入射光強度をＩ０、包装袋Ｂを透過した透過光強度をＩｔ、入射光に対する透過光の透過率をＴとして、光路長をＬ、ガス濃度をＣとすると，特定波長の吸収スペクトルで射出されたレーザー光の吸光度Ａとの間に、数式１が成立する関係である。ここでεは測定対象となる所定のガスがレーザー光を吸収する固有の吸収係数である。 Here, the tunable semiconductor laser absorption spectroscopy (TDLAS) measures the gas concentration based on Lambert-Beer's law. As shown in FIG. 3, Lambert-Beer's law is that the incident light intensity is I 0 , the transmitted light intensity transmitted through the packaging bag B is It, the transmittance of the transmitted light with respect to the incident light is T, and the optical path length is L. Assuming that the gas concentration is C, the relationship is such that Equation 1 holds with the absorbance A of the laser light emitted in the absorption spectrum of a specific wavelength. Here, ε is a unique absorption coefficient at which a predetermined gas to be measured absorbs laser light.

Figure 2021067633
Figure 2021067633

第１反射面３０と第２反射面３１との間の距離とレーザー光を反射させる反射回数から光路長Ｌを容易に求めることができることから、入射光に対する透過光の透過率Ｔ、または包装袋内で特定ガスに吸収されたレーザー光の特定波長に係る吸収スペクトルの吸光度Ａを得ることが出来れば、ガス濃度Ｃを求めることができる。
ここで、特定ガスは包装袋Ｂに密封されているから、ガス濃度Ｃを定量測定する場合、入射光に対する透過光の透過率Ｔ又は吸収スペクトルの吸光度Ａが大きく変化するように、すなわち、吸光度Ａに比例する光路長Ｌを長くするとガス濃度の検知感度を向上させることができる。このように検知感度を向上させることによって、たとえば数ｐｐｍレベルのガス濃度まで検知できるように検知可能範囲を広げた場合、数％レベルのガス濃度の測定は容易に行うことができ、その測定精度を大きく向上させることができる。
したがって、以下に例示するように、第１ガイド３０上に設ける第１窓部１６と、第２ガイド３１上に設ける第２窓部２３の位置を定めて、第１ガイド３０と第２ガイド３１との間でレーザー光を斜めに射出させることによって、光路長を長くすることができ、測定精度を向上させることができる。 Since the optical path length L can be easily obtained from the distance between the first reflecting surface 30 and the second reflecting surface 31 and the number of reflections that reflect the laser light, the transmittance T of the transmitted light with respect to the incident light or the packaging bag. If the absorbance A of the absorption spectrum related to the specific wavelength of the laser light absorbed by the specific gas can be obtained, the gas concentration C can be obtained.
Here, since the specific gas is sealed in the packaging bag B, when the gas concentration C is quantitatively measured, the transmittance T of the transmitted light with respect to the incident light or the absorbance A of the absorption spectrum changes significantly, that is, the absorbance. By increasing the optical path length L proportional to A, the detection sensitivity of the gas concentration can be improved. By improving the detection sensitivity in this way, for example, when the detectable range is expanded so that gas concentration of several ppm level can be detected, measurement of gas concentration of several% level can be easily performed, and the measurement accuracy thereof. Can be greatly improved.
Therefore, as illustrated below, the positions of the first window portion 16 provided on the first guide 30 and the second window portion 23 provided on the second guide 31 are determined, and the first guide 30 and the second guide 31 are determined. By emitting the laser beam diagonally between the and, the optical path length can be lengthened and the measurement accuracy can be improved.

第１窓部１６の位置と第２窓部２３の位置は、たとえば、図４に示した第１透過パターンから図６に示した第３透過パターンのように配置し、それに伴うレーザー光の光跡もまた次のように例示することができる。
なお、本実施例に係るガス濃度測定装置１０の第１窓部１６と第２窓部２３の配置と反射回数は以下の例示に限定されるものではなく、本実施例に係るガス濃度測定装置１０が測定する包装袋の大きさ、厚み、レーザー光の透過しやすさ等に応じて最適な透過率、吸光度を得るために任意に設定することができる。 The position of the first window portion 16 and the position of the second window portion 23 are arranged, for example, from the first transmission pattern shown in FIG. 4 to the third transmission pattern shown in FIG. Traces can also be illustrated as follows.
The arrangement and the number of reflections of the first window portion 16 and the second window portion 23 of the gas concentration measuring device 10 according to the present embodiment are not limited to the following examples, and the gas concentration measuring device according to the present embodiment. It can be arbitrarily set in order to obtain the optimum transmittance and absorbance according to the size and thickness of the packaging bag measured by 10 and the ease of transmitting laser light.

図４は、ガス濃度測定装置１０の構成の概略を示す横断面図である。第１透過パターンは、第１ガイド３０と第２ガイド３１の横断面図を平面視したとき、レーザー発生部１１とレーザー受光部１２が互いに同じ高さに配置され、レーザー発生部１１に対してレーザー受光部１２が正対せず、横へズレているパターンである。すなわち、図４に示すように、同一平面上でレーザー発生部１１を内蔵する第１ハウジング１５が備える第１窓部１６と、レーザー受光部１２を内蔵する第２ハウジング２２が備える第２窓部２３が包装袋Ｂを挟んで対角に配置されているパターンである。
第１透過パターンは、第１窓部１６から射出されるレーザー光が、包装袋Ｂを透過した後、第２窓部２３を設けた第２ガイド３１面に対して６０度の入射角を成すように第２窓部２３へ入射するように形成されている。ここで、図７に示した従来の主ヘッド３と副ヘッド５が正対している場合の光路長を１０ｃｍ、すなわち本実施例に係る第１ガイド３０と第２ガイド間の距離を１０ｃｍとすると、図４に示した光路長は従来例に対して２倍の２０ｃｍまで延ばすことができる。 FIG. 4 is a cross-sectional view showing an outline of the configuration of the gas concentration measuring device 10. In the first transmission pattern, when the cross-sectional views of the first guide 30 and the second guide 31 are viewed in a plan view, the laser generating unit 11 and the laser receiving unit 12 are arranged at the same height with respect to the laser generating unit 11. This is a pattern in which the laser receiving unit 12 does not face each other and is displaced sideways. That is, as shown in FIG. 4, the first window portion 16 included in the first housing 15 containing the laser generating portion 11 and the second window portion 22 included in the second housing 22 incorporating the laser receiving portion 12 on the same plane. 23 is a pattern arranged diagonally across the packaging bag B.
In the first transmission pattern, the laser light emitted from the first window portion 16 passes through the packaging bag B, and then forms an incident angle of 60 degrees with respect to the 31st surface of the second guide provided with the second window portion 23. It is formed so as to be incident on the second window portion 23. Here, assuming that the optical path length when the conventional main head 3 and the sub head 5 shown in FIG. 7 face each other is 10 cm, that is, the distance between the first guide 30 and the second guide according to the present embodiment is 10 cm. , The optical path length shown in FIG. 4 can be extended to 20 cm, which is twice that of the conventional example.

図５は、ガス濃度測定装置１０の構成の概略を示す縦断面図である。第２透過パターンは、図５に示すように、第１ガイド３０と第２ガイド３１の縦断面を側面視したとき、レーザー発生部１１に対してレーザー受光部１２が下方に配置されているパターンである。すなわち、縦断面の同一面上でレーザー発生部１１を内蔵する第１ハウジング１５が備える第１窓部１６と、レーザー受光部１２を内蔵する第２ハウジング２２が備える第２窓部２３が包装袋Ｂを挟んで対角に配置されているパターンである。
第２透過パターンは、第１窓部１６から射出されるレーザー光が、第２窓部２３を設けた第２ガイド３１面に対して所定の入射角となるように、包装袋Ｂを斜めに透過して第２窓部２３へ入射するように形成されている。ここで、図７に示した従来の主ヘッド３と副ヘッド５が正対している場合の光路長、すなわち第１ガイド３０と第２ガイド３０間の距離を基準とすると、図５に示した光路長は従来の光路長よりも長くすることができる。
なお、図５に示した例に限定されるものではなく、第１窓部１６に対して第２窓部２３を上方に配置しても良い。 FIG. 5 is a vertical cross-sectional view showing an outline of the configuration of the gas concentration measuring device 10. As shown in FIG. 5, the second transmission pattern is a pattern in which the laser light receiving unit 12 is arranged below the laser generating unit 11 when the vertical cross section of the first guide 30 and the second guide 31 is viewed from the side. Is. That is, the first window portion 16 included in the first housing 15 incorporating the laser generating portion 11 and the second window portion 23 provided in the second housing 22 incorporating the laser receiving portion 12 on the same surface of the vertical cross section are packaging bags. It is a pattern arranged diagonally across B.
In the second transmission pattern, the packaging bag B is obliquely arranged so that the laser beam emitted from the first window portion 16 has a predetermined incident angle with respect to the second guide 31 surface provided with the second window portion 23. It is formed so as to pass through and enter the second window portion 23. Here, the optical path length when the conventional main head 3 and the sub head 5 shown in FIG. 7 face each other, that is, the distance between the first guide 30 and the second guide 30 is used as a reference, and is shown in FIG. The optical path length can be longer than the conventional optical path length.
The example is not limited to the example shown in FIG. 5, and the second window portion 23 may be arranged above the first window portion 16.

図６は、ガス濃度測定装置１０の構成の概略を示す斜視図である。第３透過パターンは、レーザー発生部１１に対して、レーザー受光部１２が包装袋Ｂを挟んで対角に配置されているパターンである。すなわち、図６に示すように、第１ガイド３０と第２ガイド３１の距離を奥行き、第１窓部１６と第２窓部２３の上下方向の差を高さ、第１窓部１６と第２窓部２３の左右方向の距離を幅として、頂点に第１窓部１６と第２窓部２３を含む直方体を想定したとき、第１窓部１６から第２窓部２３に対してレーザー光が当該直方体の対角線に沿って射出されるように形成されている。
ここで、図７に示した従来の主ヘッド３と副ヘッド５が正対している場合の光路長を１０ｃｍ、すなわち、図６に示した第１ガイド３０と第２ガイド３１間の距離を１０ｃｍとして、上記のように想定した直方体の奥行きが１０ｃｍ、高さが４０ｃｍ、幅が２０ｃｍとすると、図６に示した光路長は従来例に対しておよそ４．６倍となる４５．８ｃｍまで延ばすことができる。 FIG. 6 is a perspective view showing an outline of the configuration of the gas concentration measuring device 10. The third transmission pattern is a pattern in which the laser light receiving unit 12 is arranged diagonally with respect to the laser generating unit 11 with the packaging bag B interposed therebetween. That is, as shown in FIG. 6, the distance between the first guide 30 and the second guide 31 is the depth, the difference between the first window portion 16 and the second window portion 23 in the vertical direction is the height, and the first window portion 16 and the first window portion 16 and the second. When a rectangular parallelepiped including the first window portion 16 and the second window portion 23 at the apex is assumed with the distance in the left-right direction of the two window portions 23 as the width, laser light is emitted from the first window portion 16 to the second window portion 23. Is formed so as to be ejected along the diagonal line of the rectangular parallelepiped.
Here, the optical path length when the conventional main head 3 and the sub head 5 shown in FIG. 7 face each other is 10 cm, that is, the distance between the first guide 30 and the second guide 31 shown in FIG. 6 is 10 cm. Assuming that the depth of the rectangular parallelepiped assumed above is 10 cm, the height is 40 cm, and the width is 20 cm, the optical path length shown in FIG. 6 is extended to 45.8 cm, which is about 4.6 times that of the conventional example. be able to.

上記の構成を有するガス濃度測定装置を用いて、本実施例に係るガス濃度測定方法が行われる。添付した図面にしたがって説明する。 The gas concentration measuring method according to the present embodiment is performed using the gas concentration measuring device having the above configuration. The explanation will be given according to the attached drawings.

ガス濃度測定方法は、図１に示すように、まずガス濃度測定装置１０の第１ガイド３０と第２ガイド３１の間に、測定対象の包装袋Ｂを配置する。このとき、少なくとも第１窓部１６と第２窓部２３が包装袋Ｂに密着するように、第１ガイド３０と第２ガイド３１によって包装袋Ｂを挟持する。
ここで、第１ガイド３０と第２ガイド３１が包装袋Ｂを挟持するとき、たとえば、包装機に設けた検査工程であれば、図１に示すように、包装袋Ｂの袋口近傍を左右からクリップ６，６で引張しているので、包装袋Ｂ表面のしわを伸ばして、第１窓部１６及び第２窓部２３へより一層密着させることができる。
このように、包装袋Ｂを挟持することによって、第１ガイド３０と第２ガイド３１との距離を一定にして、光路長を一定にすることができる。また、包装袋Ｂを挟持するとき、当該包装袋Ｂを第１ガイド３０と第２ガイド３１が押圧するため、包装袋Ｂに密封した窒素等の不活性ガスが漏れているか否かを検査することができる。さらには、包装袋Ｂを密着させるため、第１窓部１６及び第２窓部２３と包装袋Ｂの境界における大気の影響を除去することができ、測定精度を上げることができる。 In the gas concentration measuring method, as shown in FIG. 1, first, the packaging bag B to be measured is arranged between the first guide 30 and the second guide 31 of the gas concentration measuring device 10. At this time, the packaging bag B is sandwiched between the first guide 30 and the second guide 31 so that at least the first window portion 16 and the second window portion 23 are in close contact with the packaging bag B.
Here, when the first guide 30 and the second guide 31 sandwich the packaging bag B, for example, in the inspection process provided in the packaging machine, as shown in FIG. 1, the vicinity of the bag mouth of the packaging bag B is left and right. Since it is pulled by the clips 6 and 6, the wrinkles on the surface of the packaging bag B can be smoothed out so that the first window portion 16 and the second window portion 23 can be further brought into close contact with each other.
By sandwiching the packaging bag B in this way, the distance between the first guide 30 and the second guide 31 can be made constant, and the optical path length can be made constant. Further, when the packaging bag B is sandwiched, the first guide 30 and the second guide 31 press the packaging bag B, so that it is inspected whether or not an inert gas such as nitrogen sealed in the packaging bag B is leaking. be able to. Further, since the packaging bag B is brought into close contact with each other, the influence of the atmosphere at the boundary between the first window portion 16 and the second window portion 23 and the packaging bag B can be removed, and the measurement accuracy can be improved.

包装袋Ｂが第１ガイド３０と第２ガイド３１に挟持された後、続いてレーザー発生部１１から第１窓部１６を通じてレーザー光が射出される。レーザー光は、たとえば、図４から図６に示したように、第２ガイド３１面に設けた第２窓部２３を指向して所定の入射角度で射出され、包装袋Ｂを斜めに透過して、第２窓部２３を通じてレーザー受光部１２で受光される。 After the packaging bag B is sandwiched between the first guide 30 and the second guide 31, laser light is subsequently emitted from the laser generating portion 11 through the first window portion 16. For example, as shown in FIGS. 4 to 6, the laser beam is directed at the second window portion 23 provided on the second guide 31 surface and emitted at a predetermined incident angle, and is obliquely transmitted through the packaging bag B. Then, the light is received by the laser light receiving unit 12 through the second window unit 23.

そして、レーザー受光部１２の受光センサ２０は、包装袋Ｂを透過したレーザー光を電子的な透過光信号へ変換する。当該透過光信号は、測定部２１へ出力される。
測定部２１では、レーザー光源１３が射出したレーザー光を制御部１４で電子的に変換した入射光信号をレーザー発生部１１から取得し、上記の透過光信号と入射光信号を比較して、レーザー光の包装袋に対する透過率Ｔが測定される。当該入射光に対する透過光の透過率Ｔに基づいて、包装袋Ｂ内の特定ガスに吸収されたレーザー光の特定波長の吸収スペクトルの吸光度Ａが計算され、当該吸光度Ａに基づいて包装袋Ｂ内の特定ガスのガス濃度が測定される。 Then, the light receiving sensor 20 of the laser light receiving unit 12 converts the laser light transmitted through the packaging bag B into an electronic transmitted light signal. The transmitted light signal is output to the measuring unit 21.
The measuring unit 21 acquires an incident light signal obtained by electronically converting the laser light emitted by the laser light source 13 by the control unit 14 from the laser generating unit 11, compares the transmitted light signal with the incident light signal, and makes a laser. The transmittance T of the light to the packaging bag is measured. Based on the transmittance T of the transmitted light with respect to the incident light, the absorbance A of the absorption spectrum of the laser light absorbed by the specific gas in the packaging bag B at a specific wavelength is calculated, and the absorbance A in the packaging bag B is calculated based on the absorbance A. The gas concentration of a specific gas is measured.

なお、本実施例において、レーザー光が射出される第１窓部１６と、レーザー光が入射する第２窓部２３を例示したが、これに限定されるものではない。
たとえば、レーザー発生部１１から射出されるレーザー光を光ファイバーで分光して、第１ガイド３０に設けた二つ以上の窓部から射出し、射出された複数本のレーザー光が互いに触れて干渉しないように複数回反射させてから、第２ガイド３１に設けた二つ以上の窓部に入射させるようにして、多点測定を行っても良い。この場合には、包装袋Ｂ内の複数か所をサンプリングすることができるので、平均を取って補正等を行うことによって、測定精度を向上させることができる。 In this embodiment, the first window portion 16 from which the laser light is emitted and the second window portion 23 into which the laser light is incident have been illustrated, but the present invention is not limited thereto.
For example, the laser light emitted from the laser generating unit 11 is separated by an optical fiber and emitted from two or more windows provided in the first guide 30, and the plurality of emitted laser lights do not touch each other and interfere with each other. After reflecting the light a plurality of times as described above, the multi-point measurement may be performed by making the light incident on two or more windows provided in the second guide 31. In this case, since a plurality of locations in the packaging bag B can be sampled, the measurement accuracy can be improved by taking an average and performing correction or the like.

本実施例に係るガス濃度測定方法によれば、第１ガイド３０と第２ガイド３１で包装袋Ｂを挟持して、少なくとも第１窓部１６と第２窓部２３が包装袋に密着するようにした。
これによって、包装袋Ｂの厚みがバラバラであっても、当該包装袋Ｂを挟持する第１ガイド３０と第２ガイド３１との距離を一定にしたり、また当該距離を測定することで容易に光路長を決定することができる。光路長がわかれば、入射光に対する透過光の透過率Ｔを測定することによって、測定対象の特定ガスに固有の吸収波長帯に含まれた複数の吸収線のうち、一の吸収線に係る特定波長に合致するよう変調したレーザー光の吸収スペクトルの吸光度Ａを求めることができ、当該吸光度Ａに基づいて、包装袋内の特定ガスのガス濃度を容易に求めることができる。
また、第１窓部１６と第２窓部２３が包装袋Ｂに密着するように平板状の第１ガイド３０と第２ガイド３１が当該包装袋を挟持するように構成したことによって、第１窓部１６又は第２窓部２３と包装袋の間の大気を押し出して測定することができるので、大気中に含まれている特定ガスによる誤差を極めて小さくすることができ、測定精度を向上させることができる。 According to the gas concentration measuring method according to the present embodiment, the packaging bag B is sandwiched between the first guide 30 and the second guide 31, so that at least the first window portion 16 and the second window portion 23 are in close contact with the packaging bag. I made it.
As a result, even if the thickness of the packaging bag B is different, the distance between the first guide 30 and the second guide 31 that sandwich the packaging bag B can be kept constant, or the optical path can be easily measured by measuring the distance. The length can be determined. If the optical path length is known, by measuring the transmittance T of the transmitted light with respect to the incident light, the identification of one absorption line among the plurality of absorption lines included in the absorption wavelength band peculiar to the specific gas to be measured can be specified. The absorbance A of the absorption spectrum of the laser light modulated to match the wavelength can be determined, and the gas concentration of the specific gas in the packaging bag can be easily determined based on the absorbance A.
Further, the flat plate-shaped first guide 30 and the second guide 31 are configured to sandwich the packaging bag so that the first window portion 16 and the second window portion 23 are in close contact with the packaging bag B. Since the air between the window 16 or the second window 23 and the packaging bag can be extruded for measurement, the error due to the specific gas contained in the air can be extremely reduced, and the measurement accuracy can be improved. be able to.

１０…ガス濃度測定装置、１１…レーザー発生部、１２…レーザー受光部、
１３…レーザー光源、１４…制御部、１５…第１ハウジング、１６…第１窓部、
２０…受光センサ、２１…測定部、２２…第２ハウジング、２３…第２窓部、
３０…第１ガイド、３１…第２ガイド、
１…従来のガス濃度測定装置、２…従来のレーザー発生部、３…主ヘッド、４…従来のレーザー受光部、５…副ヘッド、６…グリップ、
Ｂ…包装袋。 10 ... Gas concentration measuring device, 11 ... Laser generating unit, 12 ... Laser receiving unit,
13 ... laser light source, 14 ... control unit, 15 ... first housing, 16 ... first window unit,
20 ... light receiving sensor, 21 ... measurement unit, 22 ... second housing, 23 ... second window unit,
30 ... 1st guide, 31 ... 2nd guide,
1 ... Conventional gas concentration measuring device, 2 ... Conventional laser generator, 3 ... Main head, 4 ... Conventional laser receiver, 5 ... Sub head, 6 ... Grip,
B ... Packaging bag.

Claims (5)

特定波長のレーザー光を、ガス置換されて密封された包装袋に透過させて、前記包装袋の透過前後で変化する特定波長の吸収スペクトルに基づいて前記包装袋の内部に残留している特定ガスのガス濃度を測定するようにしたレーザー式ガス濃度計を有するガス濃度測定方法であって、
前記レーザー光を発生するレーザー発生部と、
前記レーザー光を受光するレーザー受光部とを有し、
前記レーザー発生部から射出される前記レーザー光が、前記包装袋を斜めに透過して、前記レーザー受光部へ入射するようにしたことを特徴とするガス濃度測定方法。 A laser beam of a specific wavelength is transmitted through a sealed packaging bag that has been gas-replaced, and the specific gas remaining inside the packaging bag is based on an absorption spectrum of the specific wavelength that changes before and after transmission of the packaging bag. It is a gas concentration measuring method having a laser type gas densitometer for measuring the gas concentration of the above.
The laser generating part that generates the laser light and
It has a laser light receiving unit that receives the laser light.
A method for measuring a gas concentration, characterized in that the laser light emitted from the laser generating portion is obliquely transmitted through the packaging bag and incident on the laser receiving portion. 前記包装袋を挟んでレーザー発生部を袋の一側に配置するとともにレーザー受光部を包装袋の他側に配置したことを特徴とする請求項１に記載のガス濃度測定方法。 The gas concentration measuring method according to claim 1, wherein the laser generating portion is arranged on one side of the bag and the laser receiving portion is arranged on the other side of the packaging bag with the packaging bag interposed therebetween. 前記レーザー発生部の上方又は下方に、前記レーザー受光部を配置したことを特徴とする請求項１に記載のガス濃度測定方法。 The gas concentration measuring method according to claim 1, wherein the laser receiving portion is arranged above or below the laser generating portion. 前記レーザー発生部と前記レーザー受光部を同一高さに配置したことを特徴とする請求項２に記載のガス濃度測定方法。 The gas concentration measuring method according to claim 2, wherein the laser generating portion and the laser receiving portion are arranged at the same height. レーザー発生部とレーザー受光部を対角に配置したことを特徴とする請求項３若しくは請求項４に記載のガス濃度測定方法。 The gas concentration measuring method according to claim 3 or 4, wherein the laser generating portion and the laser receiving portion are arranged diagonally.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009014589A (en) * 2007-07-06 2009-01-22 General Packer Co Ltd Gas concentration measuring method in packaging machine
JP2010521676A (en) * 2007-03-13 2010-06-24 アドヴァンスト リキッド ロジック インコーポレイテッド Droplet actuator apparatus, configuration and method for improved absorbance detection
US20190317014A1 (en) * 2016-11-04 2019-10-17 Wilco Ag Method for measuring a concentration of a gas

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010521676A (en) * 2007-03-13 2010-06-24 アドヴァンスト リキッド ロジック インコーポレイテッド Droplet actuator apparatus, configuration and method for improved absorbance detection
JP2009014589A (en) * 2007-07-06 2009-01-22 General Packer Co Ltd Gas concentration measuring method in packaging machine
US20190317014A1 (en) * 2016-11-04 2019-10-17 Wilco Ag Method for measuring a concentration of a gas

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