JP2021096099A - Method of measuring gas concentration in sealed packaging container and gas concentration measurement device - 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 a narrow head space empty of a packaged object without damaging the sealed packaging container, and to provide a gas concentration measurement device.SOLUTION: Laser light emitted by a laser generator 11 and transmitted through a measured section 7 of a sealed packaging container 1 is reflected by a reflective surface 14 before being incident on a laser receiver 12.SELECTED DRAWING: Figure 8

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 inside with high accuracy, and a gas concentration measuring device used in the method.

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 step after the 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 currently mainstream method for measuring gas concentration is a sampling test in which an injection needle is inserted into a sealed packaging container arbitrarily selected as a sample 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 packed object is not present is narrow, it is extremely difficult to measure the gas concentration.

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. It is an object of the present invention to provide a measuring method and a gas concentration measuring device used for the measuring method.

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 a container 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 a laser light having a specific wavelength transmitted through the measured portion of the sealed packaging container to the sealed packaging container. A laser-type gas densitometer that measures the gas concentration of a specific gas remaining inside the container, and a reflective surface on which the laser beam can be reflected, which is emitted from the laser generating portion to measure the measured portion of the sealed packaging container. A method for measuring a gas concentration, which comprises reflecting a transmitted laser beam on the reflecting surface and then incidenting the transmitted laser light on the laser receiving portion (claim 1).

The reflecting surface is composed of a first reflecting surface and a second reflecting surface which are arranged so as to face each other in parallel with the measured portion of the sealed packaging container, and the laser light is reflected by the first reflecting surface and the second reflecting surface. It is preferable to reflect the light on the surface a plurality of times (claim 2).

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 a laser light of a specific wavelength are transmitted to the measured part of the sealed packaging container to be inside the sealed packaging container. A laser gas densitometer that measures the gas concentration of the remaining specific gas, and a laser that has a reflecting surface on which the laser light can be reflected, is emitted from the laser generating portion, and is transmitted through the measured portion of the sealed packaging container. The gas concentration measuring device is characterized in that the light is reflected by the reflecting surface and then incident on the laser receiving portion (claim 3).

The gas concentration measuring device has a first housing incorporating the laser light generating portion and a second housing incorporating the laser receiving portion, and the reflecting surface is the measured portion of the sealed packaging container. It has a first reflecting surface and a second reflecting surface which are arranged so as to face each other in parallel with each other, and the first reflecting surface includes a first window portion for emitting the laser beam, and the first reflecting surface or the second reflecting surface. The reflecting surface includes a second window portion on which the laser light is incident, and the laser light emitted from the first window portion is reflected a plurality of times between the first reflecting surface and the second reflecting surface. , It is preferable that it is configured to be incident on the second window portion (claim 4). When the first reflective surface and the second reflective surface are provided so that the relative separation distance can be adjusted, and the first reflective surface and the second reflective surface sandwich the measured portion of the sealed packaging container. It is preferable that the first window portion and the second window portion, and the first reflecting surface and the second reflecting surface are configured to be in close contact with the measured portion of the sealed packaging container (claimed). Item 5).

According to the gas concentration measuring method according to claim 1, the concentration of a specific gas inside can be measured with high accuracy without damaging the sealed packaging container and even when the head space where there is no object to be packaged is narrow. Can be done.
According to the gas concentration measuring method according to claim 2, 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 3, 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 be done.
According to the gas concentration measuring device according to claim 4, 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 apparatus according to claim 5, the effect of claim 3 can be more easily achieved.

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 top view of the gas concentration measuring apparatus shown in FIG. It is a partially enlarged view of the gas concentration measuring apparatus shown in FIG. 7. FIG. 7 is a view taken along the line AA of FIG. FIG. 7B is a view taken along the line BB.

In the present invention, the sealed packaging container is damaged by reflecting the laser light emitted from the laser generating unit 11 and passing through the measured portion 7 of the sealed packaging container 1 on the reflecting surface 14 and then incident on the laser receiving unit 12. We have realized a gas concentration measuring method and a gas concentration measuring device for a sealed packaging container that can measure the concentration of a specific gas inside with high accuracy even when the head space where there is no object to be packaged is narrow.

First, an example of a sealed packaging container used in the gas concentration measuring method of the present invention will be described with reference to one embodiment shown in FIGS. 1 to 5.
The sealed packaging container 1 of this embodiment is a sealed packaging container 1 capable of measuring the concentration of a specific gas inside, and has a main body 3 having an object filling space 2 inside and a head in the main body 3. It has a communication unit 5 that communicates with the space 4 and a unit 7 to be measured that has a space 6 for transmitting laser light. Hereinafter, each configuration will be described in detail in order.

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 of the present invention 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 broadly includes a sealed packaging container in which the gas concentration cannot be measured accurately due to the narrowness, 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. Although a substantially rectangular parallelepiped is formed, the form is not limited to the rectangular parallelepiped, and any form is included in the scope of the present invention.

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.

Next, the method for measuring the gas concentration of the sealed packaging container of the present invention will be described with reference to one embodiment shown in FIGS. 6 to 10.
In the gas concentration measuring method using the sealed packaging container 1 of this embodiment, the concentration of the 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. In the gas concentration measuring method, the sealed packaging container 1 has a main body portion 3 having an object filling space 2 inside, and a communicating portion 5 communicating with the head space 4 in the main body portion 3 and transmitting laser light. The gas concentration measuring device 10 has a unit 7 to be measured provided with a space 6, a laser generating unit 11 that emits laser light of a specific wavelength, a laser receiving unit 12 that receives the laser light, and a specific wavelength. A laser gas densitometer 13 for measuring the gas concentration of a specific gas remaining inside the sealed packaging container 1 by transmitting the laser light through the measured portion 7 of the sealed packaging container 1, and a reflecting surface 14 capable of reflecting the laser light The gas concentration measurement is characterized in that the laser light emitted from the laser generating unit 11 and transmitted through the measured portion 7 of the sealed packaging container 1 is reflected by the reflecting surface 14 and then incident on the laser receiving unit 12. The method. Hereinafter, the description of the sealed packaging container 1 will be described in detail as described above, and the description thereof will be omitted.

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.

In the gas concentration measuring method of this example, it is the residual specific gas 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 air is also filled inside the sealed packaging container.
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. 8, the gas concentration measuring device 10 used in the gas concentration measuring method of this embodiment is a laser including a laser generating unit 11 that emits laser light and a laser receiving unit 12 that receives laser light. It has a formula gas densitometer 13 and a reflecting surface 14 that reflects laser light.

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 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. 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 receives the laser light emitted from the laser emitting window 16 into the laser receiving window 18 at least once on the reflecting surface 14. It is preferably configured to reflect multiple times.

The reflecting surface 14 of this embodiment includes a first reflecting surface 14a having a first window portion 19 provided at a predetermined position and a second reflecting surface 14b provided with a second window portion 20 at a predetermined position. The first reflecting surface 14a and the second reflecting surface 14b are provided so as to face each other in parallel. The first reflecting surface 14a and the second reflecting surface 14b are made of, for example, a mirror-finished or mirror-polished metal, or a mirror-like film body attached to a predetermined base material, and are formed so as to be able to reflect laser light. Has been done.

The relative separation distance of the first reflection surface 14a and the second reflection surface 14b can be adjusted (relatively close or separate) by a reciprocating mechanism (a mechanism including a driving device such as a cylinder or a servomotor) (not shown). In FIG. 8, the measured portion 7 of the sealed packaging container 1 is formed so as to be able to be sandwiched between the first reflecting surface 14a and the second reflecting surface 14b. Therefore, when the measured portion 7 of the sealed packaging container 1 is sandwiched between the first reflecting surface 14a and the second reflecting surface 14b from above and below, the first reflecting surface is placed on the upper and lower surfaces of the measured portion 7 of the sealed packaging container 1, respectively. It is configured so that the 14a and the second reflecting surface 14b can be brought into close contact with each other.

Further, by locating the first window portion 19 and the second window portion 20 with respect to the measured portion 7 of the sealed packaging container 1, the measured portion of the sealed packaging container 1 is formed by the first reflecting surface 14a and the second reflecting surface 14b. When the 7 is sandwiched, the first window portion 19 and the second window portion 20 can also be brought into close contact with the measured portion 7 of the sealed packaging container 1. As a result, when the laser beam is emitted from the first window portion 19, reflected by the second reflecting surface 14b and the first reflecting surface 14ab, and incident on the second window portion 20, the specific gas contained in the atmosphere The influence of the above can be minimized, and the concentration of a specific gas can be measured with higher accuracy.

The positions of the first window portion 19 and the second window portion 20 are such that the first reflecting surface 14a and the second reflecting surface 14b are arranged while the laser beam is emitted from the first window portion 19 and incident on the second window portion 20. The distance between the first window portion 19 and the second window portion 20 and when the laser beam emitted from the first window portion 19 is incident on the second reflecting surface 14b. Depending on the relationship with the incident angle, it is possible to control the laser beam to be reflected a predetermined number of times between the first reflecting surface 14a and the second reflecting surface 14b so as to be incident on the second window portion 20.

When the laser light is emitted from the first window portion 19 and incident on the second reflecting surface 20, the incident angle of the laser light can be arbitrarily set between 5 degrees and 85 degrees, and further, the first reflecting surface 14a The optical path length can be easily calculated based on the distance between the and the second reflecting surface 14b. When the incident angle is 5 degrees or less, the first window portion 19 and the second window portion 20 face each other in the conventional manner. The difference in optical path length does not increase from the case of. On the other hand, when the incident angle is 85 degrees or more, the ratio of the transmitted laser light being scattered is larger than that absorbed by the specific gas, and there is a possibility that an error is likely to occur in the measurement of the gas concentration.

The number of reflections reflected between the first reflecting surface 14a and the second reflecting surface 14b is preferably about 2 to 4 times. If the light is reflected five times or more, the optical path length can be lengthened, but the attenuation rate of the laser light becomes large, so that the laser light receiving unit 12 must be provided with a highly sensitive light receiving sensor. Therefore, the cost may increase.

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 between the first reflecting surface 14a and the second reflecting surface 14b of the gas concentration measuring device 10 in the vicinity of the portion where the gas concentration measuring device 10 is installed, FIG. As shown in the above, the first reflecting surface 14a and the second reflecting surface 14b of the gas concentration measuring device 10 sandwich the measured portion 7 from above and below.

After the measured portion 7 of the sealed packaging container 1 is sandwiched between the first reflecting surface 14a and the second reflecting surface 14b, the laser emitting window portion 16 and the first window portion 19 of the first reflecting surface 14a are sandwiched between the first reflecting surface 14a and the second reflecting surface 14b. The laser beam is emitted from above to the measured portion 7 of the sealed packaging container 1 via the above. The laser light is first reflected by the second reflecting surface 14b, then reflected in the order of the first reflecting surface 14a and then the second reflecting surface 14b, and then the second window portion 19 and the second housing 17 of the first reflecting surface 14a. The laser light is received by the laser light receiving unit 12 via the laser light receiving window 18 of the above.

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.

In this embodiment, the reflecting surface 14 is configured to be composed of two surfaces, a first reflecting surface 14a and a second reflecting surface 14b, but the present invention is not limited to this, and for example, for one reflecting surface. The optical path length can also be extended by reflecting the laser beam.

1 Sealed packaging container 2 Packed object filling space 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 densitometer 14 Reflection Surface 14a First reflecting surface 14b Second reflecting surface 15 First housing 16 Laser emitting window 17 Second housing 18 Laser receiving window 19 First window 20 Second window,
F film w conveyor Y belt S packaged object

Claims (5)

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 portion that emits a laser beam having a specific wavelength, a laser receiving portion that receives the laser beam, and a laser beam having a specific wavelength through the measured portion of the sealed packaging container. It has a laser gas densitometer that measures the gas concentration of a specific gas remaining inside the sealed packaging container, and a reflective surface that can reflect the laser light.
A gas concentration measuring method, characterized in that a laser beam emitted from the laser generating portion and transmitted through the measured portion of the sealed packaging container is reflected by the reflecting surface and then incident on the laser receiving portion. The reflecting surface is composed of a first reflecting surface and a second reflecting surface which are arranged so as to face each other in parallel with the measured portion of the sealed packaging container, and the laser light is reflected by the first reflecting surface and the second reflecting surface. The gas concentration measuring method according to claim 1, wherein the light is reflected from the surface a plurality of times. 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 portion that emits a laser beam having a specific wavelength, a laser receiving portion that receives the laser beam, and a laser beam having a specific wavelength through the measured portion of the sealed packaging container. It has a laser gas densitometer that measures the gas concentration of a specific gas remaining inside the sealed packaging container, and a reflective surface that can reflect the laser light.
A gas characterized in that the laser light emitted from the laser generating portion and transmitted through the measured portion of the sealed packaging container is reflected by the reflecting surface and then incident on the laser receiving portion. Concentration measuring device. The gas concentration measuring device has a first housing containing the laser light generating unit and a second housing containing the laser receiving unit.
The reflective surface has a first reflective surface and a second reflective surface arranged so as to face each other in parallel with the measured portion of the sealed packaging container.
The first reflecting surface includes a first window portion for emitting the laser light, and the first reflecting surface or the second reflecting surface includes a second window portion into which the laser light is incident.
A claim that the laser light emitted from the first window portion is configured to be incident on the second window portion after being reflected a plurality of times between the first reflecting surface and the second reflecting surface. 3. The gas concentration measuring device according to 3. When the first reflective surface and the second reflective surface are provided so that the relative separation distance can be adjusted, and the first reflective surface and the second reflective surface sandwich the measured portion of the sealed packaging container. 4. The fourth aspect of claim 4, wherein the first window portion and the second window portion, and the first reflecting surface and the second reflecting surface are configured to be in close contact with the measured portion of the sealed packaging container. Gas concentration measuring device.

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