JP2021096097A - Method of measuring gas concentration in sealed packaging container and gas concentration measurement device used therefor - Google Patents

Abstract

To provide a method of measuring gas concentration in a sealed packaging container, which allows for highly accurately measuring concentration of a specific gas in a sealed packaging container even in the presence of little head space empty of a packaged object without damaging the sealed packaging container, and to provide a gas concentration measurement device used therefor.SOLUTION: Laser light emitted by a laser generator 11 to be transmitted through a laser light transmission space 6 of a measured section 7 is directed to enter the measured section 7 from one end, transmit through the laser light transmission space 6, and exit the measured section 7 from the other end to enter a laser receiver 12.SELECTED DRAWING: Figure 6

Description

The present invention relates to a gas concentration measuring method for a sealed packaging container capable of measuring the concentration of a specific gas in the sealed packaging container with high accuracy, and a gas concentration measuring device used therefor.

Conventionally, sealed packaging containers such as gas-replaced and sealed retort-molded containers (for example, retort-packed rice packs) have been widely used.
In the packaging process of this type of sealed packaging container, after removing the oxidation-causing gas (for example, oxygen) remaining in the headspace, which may shorten the storage period or the shelf life of the packaged object, nitrogen, carbon dioxide, etc. Gas replacement packaging that replaces gas with an inert gas and seals it is performed (Patent Document 1). As a result, the oxidation-causing gas in the sealed packaging container is removed, and the packaged object, particularly the food, can secure a long storage period and a shelf life.

Then, in the inspection process after gas replacement packaging, inspection is performed to see if the concentration of the gas causing oxidation, especially oxygen, is below the predetermined value, but the currently mainstream method for measuring the gas concentration is arbitrary as a sample. This is a sampling test in which an injection needle is pierced into the sealed packaging container selected in 1 and the composition of a small amount of gas sucked from the sealed packaging container is inspected. In this sampling inspection, sealed packaging containers with injection marks 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. Further, when the head space in which the packaged object does not exist is narrow in the sealed packaging container, it is extremely difficult to measure the gas concentration because the packaged object hinders the measurement.

Japanese Patent No. 3744022

Therefore, the subject of the present invention is the gas concentration of the sealed packaging container, which can measure the concentration of the specific gas inside with high accuracy without damaging the sealed packaging container, even when the head space where the object to be packaged does not exist is narrow. An object of the present invention is to provide a measuring method and a gas concentration measuring device used therein.

The solution to the above problem is a gas concentration measuring method for measuring the concentration of a specific gas in a sealed packaging container filled with an object to be packaged and replaced with a gas by a gas concentration measuring device, and the sealed packaging container is described. Has a main body portion having a space for filling the object to be packaged inside, and a unit to be measured having a communication portion communicating with the head space in the main body portion and a space for transmitting laser light, and measuring the gas concentration. The apparatus includes a laser generating unit that emits a laser beam having a specific wavelength, a laser receiving unit that receives the laser beam, and the laser light having a specific wavelength transmitted through the measured portion of the sealed packaging container to be sealed and packaged. It has a laser type gas densitometer that measures the gas concentration of a specific gas remaining inside the container, and the laser light emitted from the laser generating part and transmitted through the laser light transmitting space of the measured part. A method for measuring the gas concentration of a sealed packaging container, which comprises transmitting light from one end side of the measured portion to the laser light transmitting space and then incidenting the laser light receiving portion from the other end side of the measured portion. There is (claim 1).

The laser emitting portion and the laser receiving portion are arranged on both sides of the measured portion of the sealed packaging container so as to be relatively close to each other and can be separated from each other, and the measured portion of the sealed packaging container is to be measured. After the tip of the laser emitting portion and the tip of the laser receiving portion are brought into contact with both ends of the measured portion of the sealed packaging container, the laser beam is applied to one end of the measured portion. It is preferable that the laser light is transmitted from the side into the laser light transmitting space and further incident on the laser light receiving part from the other end side of the measured portion (claim 2). In the sealed packaging container, the laser light transmitting space of the measured portion is formed in an elongated shape, and the laser emitting portion and the laser receiving portion are relative to both sides of the measured portion in the longitudinal direction. The tip of the laser emitting part and the tip of the laser receiving part are opposed to the measured part of the sealed packaging container so as to be close to and separated from each other. After contacting both ends in the longitudinal direction of the laser beam, the laser beam is transmitted from one end side of the measured portion into the laser light transmitting space, and further, the laser receiving portion is transmitted from the other end side of the measured portion. (Claim 3).

Further, what solves the above-mentioned problem is a gas concentration measuring device for measuring the concentration of a specific gas in a sealed packaging container filled with an object to be packaged and replaced with a gas, and the sealed packaging container is inside. The gas concentration measuring device has a main body portion provided with a space for filling the object to be packaged, and a measured portion having a communication portion communicating with the head space in the main body portion and a space for transmitting laser light. A laser generating part that emits a laser beam of a specific wavelength, a laser receiving part that receives the laser light, and the laser light of a specific wavelength are transmitted through the measured part of the sealed packaging container to be inside the sealed packaging container. It has a laser type gas densitometer that measures the gas concentration of the specific gas remaining in the laser light, and the laser light emitted from the laser generating part and transmitted through the laser light transmitting space of the measured part is measured. It is a gas concentration measuring device characterized in that it is configured to be transmitted from one end side of the portion into the laser light transmitting space and then incident on the laser light receiving portion from the other end side of the measured portion. (Claim 4).

The laser emitting portion and the laser receiving portion are arranged on both sides of the measured portion of the sealed packaging container so as to be relatively close to each other and can be separated from each other, and the measured portion of the sealed packaging container is to be measured. It is preferable that the tip of the laser emitting portion and the tip of the laser receiving portion are in contact with both ends of the measured portion of the sealed packaging container with respect to the portion (claim 5). .. In the sealed packaging container, the laser light transmitting space of the measured portion is formed in an elongated shape, and the laser emitting portion and the laser receiving portion are formed in the longitudinal direction of the measured portion of the sealed packaging container. It is preferable that the two sides are arranged so as to be relatively close to each other and separated from each other (claim 6).

According to the gas concentration measuring method according to claim 1 or 2, the concentration of a specific gas inside is measured with high accuracy without damaging the sealed packaging container, even when the head space where there is no object to be packaged is narrow. can do.
According to the gas concentration measuring method according to claim 3, the optical path length of the laser beam can be made longer, and the concentration of the specific gas inside the sealed packaging container can be measured with higher accuracy.
According to the gas concentration measuring device according to claim 4 or 5, the concentration of a specific gas inside can be measured with high accuracy without damaging the sealed packaging container, even when the head space where there is no object to be packaged is narrow. can do.
According to the gas concentration measuring device according to claim 6, the optical path length of the laser beam can be made longer, and the concentration of the specific gas inside the sealed packaging container can be measured with higher accuracy.

It is explanatory drawing for demonstrating the operation of one Example of the sealed packaging container used in the gas concentration measurement method of this invention. It is a front view of the sealed packaging container shown in FIG. It is a right side view of the sealed packaging container shown in FIG. It is a top view of the sealed packaging container shown in FIG. It is a front view which shows the use state of the sealed packaging container shown in FIG. It is a top view of an Example of the gas concentration measuring apparatus used in the gas concentration measuring method of this invention. It is a right side view of the gas concentration measuring apparatus shown in FIG.

In the present invention, the laser light emitted from the laser generation unit 11 and transmitted through the laser light transmission space 6 of the measurement unit 7 is transmitted from one end side of the measurement unit 7 to the laser light transmission space 6 and then transmitted. By making the laser light receiving part 12 enter the laser receiving part 12 from the other end side of the measured part 7, the concentration of the specific gas inside can be increased without damaging the sealed packaging container even when the head space where the object to be measured does not exist is narrow. We have realized a method for measuring the gas concentration of a sealed packaging container and a gas concentration measuring device that can measure accurately.

An embodiment of the method for measuring the gas concentration of a sealed packaging container of the present invention will be described with reference to one embodiment shown in FIGS. 1 to 7.
The gas concentration measuring method of the sealed packaging container of this embodiment is a gas concentration measurement in which the concentration of a specific gas in the sealed packaging container 1 filled with the object to be packaged S and replaced with gas is measured by the gas concentration measuring device 10. According to the method, the sealed packaging container 1 has a main body portion 3 having an object filling space 2 inside, and a communication portion 5 communicating with a head space 4 in the main body portion 3, and a laser light transmitting space 6 is provided. The gas concentration measuring device 10 includes a laser emitting unit 11 that emits a laser beam having a specific wavelength, a laser receiving unit 12 that receives the laser beam, and the laser beam having a specific wavelength. Has a laser type gas densitometer 13 for measuring the gas concentration of a specific gas remaining inside the sealed packaging container 1 by permeating the measured portion 7 of the sealed packaging container 1, and is ejected from the laser generating unit 11 to be covered. The laser light transmitted through the laser light transmitting space 6 of the measuring unit 7 is transmitted from one end side of the measured unit 7 to the laser light transmitting space 6, and then the laser receiving unit is transmitted from the other end side of the measured unit 7. It is a method for measuring a gas concentration in a sealed packaging container, which comprises making the laser incident on 12. The details will be described below.

The sealed packaging container 1 of this embodiment is a container for retort cooked rice, and the specific gas inside is oxygen. However, the sealed packaging container is not limited to this, and as shown in FIG. 1, the object to be packaged (rice in this embodiment) S is sufficiently filled in the sealed packaging container 1 and the head space 4 is narrow. Therefore, it broadly includes a sealed packaging container whose gas concentration cannot be measured accurately, and also includes a sealed packaging container containing a specific gas other than oxygen.

Inside the main body 3, a packaged filling space 2 for filling the packaged object (rice in this embodiment) S is provided. In this embodiment, the packaged object 3 and the packaged object filling space 2 are provided. Is formed into a substantially rectangular parallelepiped, but the form is not limited to the rectangular parallelepiped, and any form may be used.

The unit 7 to be measured has a space 6 for transmitting laser light inside, and is a portion for transmitting laser light to measure the concentration of a specific gas, and is a communication unit communicating with the head space 4 in the main body 3. It is provided adjacent to the main body portion 3 via 5. However, the measured portion 7 of this embodiment is separately provided adjacent to the main body portion 3, but is not limited to this, and can measure the concentration of a specific gas by transmitting laser light. Any form may be used as long as it is used, and for example, a space for filling the object to be packaged and a space for transmitting laser light are partitioned by a partition plate or the like in the main body, and the like is also included in the scope of the present invention. It is preferable that the unit 7 to be measured has a structure in which only the gas in the head space 4 is transferred via the communication unit 5, but the moisture content and the water content are within a range that does not interfere with the measurement of the concentration of the specific gas by the laser beam. A small amount of the package S may be transferred in a small amount.

The sealed packaging container 1 of this embodiment is integrally molded with a transparent material (for example, polypropylene or the like) in order to allow a laser beam to pass through the part to be measured 7 and measure the concentration of a specific gas. However, the sealed packaging container of the present invention is not limited to this, and only the portion constituting the part to be measured may be formed of a transparent material, and further, the concentration of a specific gas can be measured. The main body and / and the part to be measured may be formed of a material capable of transmitting a laser beam having a specific wavelength. In the present application, the "transparent material" broadly includes a transparent or translucent material regardless of the presence or absence of color. Further, in the present application, the material capable of transmitting the laser light of a specific wavelength is a material capable of transmitting the laser light of a specific wavelength regardless of whether it is transparent or translucent, a material, a pattern, a character or a figure, etc., or colored. Is widely included.

Further, it is preferable that the laser light transmitting space 6 of the measured portion 7 is formed in an elongated shape as in this embodiment. As a result, the optical path length of the laser beam can be secured longer, and the measurement accuracy of the specific gas concentration can be improved. A film F is attached to the upper surface of the sealed packaging container 1 of this embodiment, and the sealed state of the object filling space 2, the communication portion 5, and the laser light transmitting space 6 is maintained.

The gas concentration measuring method of this embodiment is a method of measuring the gas concentration of a specific gas remaining in the sealed packaging container 1, and is performed at an inspection site where the sealed packaging container 1 is inspected before shipment, or is packaged. It is carried out in the inspection process of a rotary type or pillow type packaging machine having various processes related to the above.

Further, in the gas concentration measuring method of this example, the residual specific gas oxygen gas (O ₂ ) is used. In the packaging process of the packaging machine performed in an air atmosphere, when the object to be packaged is filled, the air is also filled inside the sealed packaging container 1.
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 step of filling the sealed packaging container with the object to be packaged, the air is evacuated from the sealed packaging container, and an inert gas such as nitrogen gas (N ₂ ) or carbon dioxide gas is used. A gas replacement (gas purge) step of replacing with (CO _{2) is provided.}

After that, the gas concentration measuring method according to the present embodiment is a method of measuring the gas concentration of oxygen gas in the gas-replaced sealed packaging container 1 and inspecting whether the gas concentration is within the reference value or less. When the gas concentration of oxygen gas is measured, if the gas concentration is below the standard value, the gas replacement is performed normally, and the sealed packaging container 1 is filled with the inert gas. It is possible to prevent the oxidation of the gas, and to extend the storage period and the best-before date. On the other hand, if the gas concentration exceeds the standard value, it is determined to be a defective product, and the product is discharged, for example, in the packaging process of the packaging machine (defective product discharge process).

As shown in FIG. 6 or 7, the gas concentration measuring device 10 used in the gas concentration measuring method of this embodiment includes a laser generating unit 11 that emits laser light and a laser receiving unit 12 that receives laser light. It has a laser type gas densitometer 13 provided.

The laser gas densitometer 13 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 gas containing a predetermined incident light intensity related to the laser light output from the semiconductor laser element and a specific gas to be measured. This is a method of measuring the gas concentration from the absorbance of the laser beam based on the transmittance by obtaining the transmittance from the transmitted light intensity related to the transmitted laser light absorbed by the specific gas after passing through the cell in which the seal is sealed. ..

It is known that each gas, including a specific gas, has its own 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 in the near-infrared region of the output laser light so as to match the specific wavelength of one absorption line among the multiple absorption lines of the specific gas to be measured. It is configured in. 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 the sealed packaging container 1.

The laser generation unit 11 has a laser light source and a control unit that sets the wavelength of the laser light emitted from the laser light source to a specific wavelength and adjusts it to a predetermined light intensity.
The laser light source 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 adjusts the wavelength of the laser light output from the semiconductor laser element to a specific wavelength specific 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. Is formed in.

Here, since the specific gas measured by the laser gas concentration meter 13 according to the present embodiment is oxygen gas, the absorption wavelength band peculiar to the oxygen gas is 760 nm, and a plurality of absorption wavelength bands included in the absorption wavelength band. Of the absorption lines of, the specific wavelength related to one absorption line is selected as the output wavelength of the laser beam.

The laser generating unit 11 is built in the first housing 15, and the first housing 15 has a laser emitting window portion 16. A sapphire glass that easily allows light in the near infrared region to pass through is fitted in the laser injection window portion 16. The laser generating unit 11 is formed so as to emit laser light from the first housing 15 through the laser emitting window portion 16 (the tip end portion of the laser emitting unit 11).

The inside of the first housing 15 is formed so that vacuuming or gas replacement (gas purging) can be performed in order to remove the specific gas, oxygen gas in this embodiment. Therefore, the inside of the first housing 15 can be maintained in a vacuum or filled with nitrogen gas or an inert gas such as carbon dioxide. As a result, it is possible to prevent the laser light from being absorbed by the specific gas in the first housing 15 during the period from the laser light source to the laser emission window 16, and the accuracy of the gas concentration measurement is improved. Can be made to.

The laser light receiving unit 12 has a light receiving sensor that receives the laser light transmitted through the measured unit 7 of the sealed packaging container 1 and a measuring unit that measures the gas concentration based on the light receiving signal from the light receiving sensor.

The light receiving sensor is composed of an element that converts the transmitted light intensity of the laser light transmitted through the measured portion 7 of the sealed packaging container 1 into an electrically transmitted light signal, for example, a photodiode. As a result, the transmitted light intensity of the laser light transmitted through the measured portion 7 of the sealed packaging container 1 can be electrically processed.

The measuring unit 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 light is based on the transmittance. The absorbance of the specific gas is determined, and the concentration of the specific gas in the measured portion 7 of the sealed packaging container 1 is measured based on the absorbance.

The laser light receiving unit 12 is built in the second housing 17. The second housing 17 has a laser receiving window portion 18 (a tip portion of the laser receiving portion 12). Similar to the laser emitting window portion 16, the laser receiving window portion 18 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 measured portion 7 of the sealed packaging container 1 through the laser light receiving window portion 18.

The inside of the second housing 17 is also formed so as to be evacuated or gas-replaceable like the first housing 15. Therefore, it is possible to prevent the laser light from being absorbed by the specific gas in the second housing 17 until the light receiving sensor receives the laser light incident through the laser light receiving window portion 18, and the gas concentration is measured. The accuracy of the can be improved.

In this way, the laser gas densitometer 13 emits laser light from the laser generating unit 11 through the laser emitting window portion 16 and transmits the laser light into the measured portion 7 of the sealed packaging container 1 to be measured. Therefore, the laser light receiving unit 12 is configured to receive the laser light transmitted through the measured portion 7 of the sealed packaging container 1 through the laser light receiving window portion 18.

Then, the gas concentration measuring device 10 having the laser type gas concentration meter 13 emits the laser light emitted from the laser generating unit 11 and transmitted through the laser light transmitting space 6 of the measured unit 7 from one end side of the measured unit 7. After being transmitted through the laser light transmitting space 6, it is configured to be incident on the laser receiving unit 12 from the other end side of the measured unit 7.

Next, a specific operation of the gas concentration measuring method and the gas concentration measuring device of the present invention will be described with reference to an embodiment shown in the drawings.

In the gas concentration measuring method and the gas concentration measuring device 10 of the present invention, as shown in FIG. 6 or 7, the sealed packaging container 1 placed on the belt Y of the conveyor W is sequentially intermittently conveyed. The sealed packaging container 1 is placed on the belt Y so that the sealed packaging container 1 is transported along the longitudinal direction of the measured portion 7 of the sealed packaging container 1 in the transport direction (arrow H direction) in FIG.

Then, when the measured portion 7 of the sealed packaging container 1 reaches the vicinity of the portion where the gas concentration measuring device 10 is installed, as shown in FIG. 6 or 7, the first housing 15 and the second housing 15 and the second of the gas concentration measuring device 10 are installed. The housing 17 is inside (in the direction orthogonal to the transport direction of the conveyor W) by the first reciprocating mechanism (including the first cylinder 21) 19 or the second reciprocating mechanism (including the second cylinder 22) 20, respectively. The tip of the laser emitting portion 11 (the window portion 16 for laser injection) and the tip portion of the laser receiving portion 12 (the window portion 18 for receiving the laser) are moved to the belt Y side from both sides of the sealed packaging container 1. It is configured to be in surface contact with both ends of the device to be measured 7.

After the laser emitting window 16 and the laser receiving window 18 are in surface contact with both end surfaces of the measured portion 7 of the sealed packaging container 1, the laser emitting portion 11 is sealed and packaged via the laser emitting window 16. A laser beam is emitted to one end side of the measured portion 7 of the container 1. The laser light travels in the laser light transmitting space 6 of the measured portion 7, and receives laser light through the laser receiving window portion 18 of the second housing 17 which is in surface contact with the other end side of the measured portion 7. The light is received by the unit 12.

The light receiving sensor of the laser light receiving unit 12 converts the laser light transmitted through the measured unit 7 of the sealed packaging container 1 into an electronic transmitted light signal, and the transmitted light signal is output to the measuring unit. The measuring unit acquires the transmitted light signal and the incident light signal obtained by electronically converting the laser light emitted by the laser generating unit 11, compares the transmitted light signal with the incident light signal, and compares the transmitted light signal with the incident light signal to seal and package the laser light. The transmittance T with respect to the measured portion 7 of 1 is measured. Then, based on the transmittance T, the absorbance of the absorption spectrum of the laser beam absorbed by the specific gas in the measured portion 7 of the sealed packaging container 1 at a specific wavelength is calculated, and the sealed packaging container 1 is calculated based on the absorbance. The gas concentration of the specific gas in the unit 7 to be measured is measured.

1 Sealed packaging container 2 Filled space for objects to be packaged 3 Main body 4 Head space 5 Communication part 6 Laser light transmission space 7 Measured part 10 Gas concentration measuring device 11 Laser generating part 12 Laser receiving part 13 Laser type gas concentration meter 15th 1 Housing 16 Laser injection window 17 Second housing 18 Laser light receiving window 19 First reciprocating mechanism 20 Second reciprocating mechanism 21 First cylinder 22 Second cylinder F Film w Conveyor Y Belt S Packaged object

Claims (6)

It is a gas concentration measuring method in which the concentration of a specific gas in a sealed packaging container filled with an object to be packaged and replaced with gas is measured by a gas concentration measuring device.
The sealed packaging container has a main body portion having a space for filling the object to be packaged inside, and a unit to be measured having a communication portion communicating with the head space in the main body portion and a space for transmitting laser light.
The gas concentration measuring device transmits a laser generating unit that emits a laser beam having a specific wavelength, a laser receiving unit that receives the laser beam, and the laser light having a specific wavelength through the measured unit of the sealed packaging container. It also has a laser gas densitometer that measures the gas concentration of the specific gas remaining inside the sealed packaging container.
The laser light emitted from the laser generating unit and transmitted through the laser light transmitting space of the measured unit is transmitted from one end side of the measured unit to the laser light transmitting space, and then the measured unit. A method for measuring the gas concentration of a sealed packaging container, which comprises incident the laser on the laser receiving portion from the other end side. The laser emitting unit and the laser receiving unit are arranged to face each other on both sides of the measured portion of the sealed packaging container, and are configured to be relatively close to each other and separated from each other.
The tip of the laser emitting portion and the tip of the laser receiving portion are brought into contact with both ends of the measured portion of the sealed packaging container with respect to the measured portion of the sealed packaging container, and then the laser is used. The gas concentration of the sealed packaging container according to claim 1, wherein light is transmitted from one end side of the measured portion into the laser light transmitting space and further incident on the laser receiving portion from the other end side of the measured portion. Measuring method. In the sealed packaging container, the space for transmitting laser light in the part to be measured is formed in an elongated shape.
The laser emitting unit and the laser receiving unit are arranged so as to face each other so as to be relatively close to each other and separated from each other on both sides of the measured portion in the longitudinal direction.
After the tip of the laser emitting portion and the tip of the laser receiving portion are brought into contact with both ends of the sealed packaging container in the longitudinal direction with respect to the measured portion of the sealed packaging container. The sealed packaging container according to claim 2, wherein the laser beam is transmitted from one end side of the measured portion into the laser light transmitting space, and further incident on the laser receiving portion from the other end side of the measured portion. Gas concentration measurement method. A gas concentration measuring device that measures the concentration of a specific gas in a sealed packaging container that is packed with an object to be packaged and replaced with gas.
The sealed packaging container has a main body portion having a space for filling the object to be packaged inside, and a unit to be measured having a communication portion communicating with the head space in the main body portion and a space for transmitting laser light.
The gas concentration measuring device transmits a laser generating unit that emits a laser beam having a specific wavelength, a laser receiving unit that receives the laser beam, and the laser light having a specific wavelength through the measured unit of the sealed packaging container. It also has a laser gas densitometer that measures the gas concentration of the specific gas remaining inside the sealed packaging container.
The laser light emitted from the laser generating unit and transmitted through the laser light transmitting space of the measured unit is transmitted from one end side of the measured unit to the laser light transmitting space, and then the measured unit. A gas concentration measuring device characterized in that it is configured to be incident on the laser receiving portion from the other end side of the above. The laser emitting portion and the laser receiving portion are arranged on both sides of the measured portion of the sealed packaging container so as to be relatively close to each other and can be separated from each other, and the measured portion of the sealed packaging container is to be measured. The gas concentration according to claim 4, wherein the tip of the laser emitting portion and the tip of the laser receiving portion are in contact with both ends of the measured portion of the sealed packaging container. measuring device. In the sealed packaging container, the laser light transmitting space of the measured portion is formed in an elongated shape, and the laser emitting portion and the laser receiving portion are formed in the longitudinal direction of the measured portion of the sealed packaging container. The gas concentration measuring device according to claim 5, wherein the gas concentration measuring devices are arranged so as to be relatively close to each other and separated from each other on both sides.

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