JP2016223924A - Method and device for measuring gas permeation amount - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measuring device applying a principle of the differential pressure method to the gas permeation measurement of a container and having reproducibility of a measurement result.SOLUTION: A gas permeation measurement method for measuring a gas permeation amount of a container to be measured includes the following steps of a to e. (a) a step of making an internal space of a container to be measured and one space of an indoor space surrounded by an internal wall of a measurement chamber and an external wall of the container to be measured to be used as a vacuum partitioned chamber 6 and making the other internal space to be used as a normal pressure partitioned chamber 7 by positioning the container 2 to be measured in the internal part of the measurement chamber 21, (b) a step of filling a granular material 11 into the vacuum partitioned chamber and protecting the container to be measured from a deformation by resisting to a force deforming the wall surface of the container to be measured which is generated from a pressure difference between the inside of the container to be measured and the outside of the container to be measured, (c) a step of positioning a test gas 24 in the normal pressure partitioned chamber 7, (d) a step of reducing the pressure of the vacuum partitioned chamber 6, and (e) after performing the steps of (c) and (d), a step of measuring the test gas reaching the vacuum partitioned chamber from the normal pressure partitioned chamber by permeating the wall surface of the container to be measured.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and apparatus for measuring the gas permeability of a container made of plastic or the like.

  Conventionally, an isobaric method and a differential pressure method are known as methods for testing the gas permeability of films and sheets made of plastic materials (see, for example, Patent Document 1).

  In the gas permeability test method using the film isobaric method, a test piece is placed between two chambers A and B, a test gas is supplied to chamber A, and a carrier gas is flowed to chamber B. The test gas passes through the test piece and moves into the carrier gas in the chamber B, is carried to the sensor by the carrier gas, and is measured by the sensor.

  In the gas permeability test method by the film differential pressure method, a test piece is placed between two chambers A and B, the chamber B is evacuated, and a test gas is introduced into the chamber A. The test gas passes through the test piece and moves to chamber B. The amount of test gas that has permeated through the test piece is known by measuring the amount of test gas in chamber B or measuring the increase in pressure in chamber B.

  Conventionally, gas permeation measurement has been performed on containers of fluids (mayonnaise, ketchup, etc.) and liquid beverages (green tea, juice, etc.). In the measurement method, a container to be measured is arranged in a test gas atmosphere, and a carrier gas is caused to flow in from the inlet / outlet of the container to be measured. In this method, the test gas that has permeated into the container to be measured is guided to the sensor by being put on the flow of the carrier gas, and the test gas is measured by the sensor. Since the test gas and the carrier gas have the same pressure in this measurement method, the measurement method is temporarily referred to as a container isobaric method in this specification.

  In the container isobaric method, the amount of test gas in the carrier gas is measured. The lower limit value of the test gas that can be measured is determined by the flow rate of the carrier gas and the sensitivity of the sensor. The practical minimum value of the carrier gas flow rate is approximately several ml / min, and there is a limit to reduce the measurement lower limit value by reducing the carrier gas flow rate. Increasing the sensitivity of the sensor makes the device expensive.

  On the other hand, as described above, there is a differential pressure method as a method for measuring the gas permeability of films and sheets. When the same detector is used for both the differential pressure method and the isobaric method in the film and the sheet, the differential pressure method can obtain the measured value of the sample with less test gas permeation compared to the isobaric method. That is, the minimum detection capability in gas permeation measurement is improved.

  However, if the principle of the differential pressure method in a film or the like is applied to the measurement of the container, it is indispensable to evacuate the inside of the container. As a result, the container is deformed and gas permeation according to the actual condition of the container is obtained. It is difficult to obtain reproducible measurement results. Especially for containers made of polyethylene, etc., where the contents can be squeezed from the outside of the container, the deformation of the container due to the pressure difference inside and outside the container is severe, and accurate gas permeation measurement and reproduction It is difficult to obtain a reliable measurement result.

Utility Model Registration No. 3096609

  The problem to be solved by the present invention is to measure the gas permeation of a container and apply the principle of a differential pressure method such as a film, so that the actual condition of the container (the thickness of the side wall, bottom surface, inlet / outlet portion is different, etc.) The object is to obtain a gas permeation measuring method and a measuring apparatus that are in accordance with the performance of the whole and have reproducibility of measurement results.

  Other problems of the present invention will become apparent from the description of the present invention.

  Means for solving the problems will be described below. For ease of understanding, description will be made with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited to the embodiments.

A gas permeation measuring method according to one aspect of the present invention is a gas permeation measuring method for measuring a gas permeation amount of a container to be measured, and includes the following steps.
A. By positioning the container to be measured (2) inside the measurement chamber (21), the internal space of the container to be measured and one space of the indoor space surrounded by the inner wall of the measurement chamber and the outer wall of the container to be measured are decompression compartments ( 6) and the other space is the normal pressure compartment (7). This is the process of filling the vacuum chamber with the granular material (11), and the granular material deforms the measured container against the force that deforms the measured container wall surface due to the pressure difference between the measured container and the measured container. That protects from the
C. Positioning the test gas (24) in the atmospheric pressure compartment; Step of reducing the pressure in the decompression compartment e. The step of measuring the test gas that has permeated through the wall of the container to be measured and has reached the decompression compartment after passing through the steps c and d.

  In a preferred embodiment of the present invention, the internal space of the container to be measured may be a decompression compartment.

  In another preferred embodiment of the present invention, the granular material may have a circumscribed sphere diameter of 0.05 mm or more and 10.0 mm or less, and may have a spherical shape. The granular material may be made of metal.

According to another aspect of the present invention, a gas permeation measuring apparatus for a container to be measured is a gas permeation measuring apparatus for measuring a gas permeation amount of a container to be measured.
Consists of measurement chamber (21), granular material (11), vacuum pump (31), test gas (24) and gas detector (32)
The container to be measured (2) is positioned inside the measurement chamber,
One space of the inner space of the container to be measured and the space surrounded by the inner wall of the measurement chamber and the outer wall of the container to be measured is a decompression compartment (6), and the other space is a normal pressure compartment (7),
The decompression compartment is filled with particulate matter, and the particulate matter protects the measured container from deformation against the force that deforms the measured container wall surface caused by the pressure difference between the measured container and outside the measured container.
The vacuum pump is connected to and disconnected from the decompression compartment,
The test gas is positioned in the atmospheric pressure compartment,
The pressure of the decompression compartment is reduced, and the test gas that passes through the wall of the container to be measured from the normal pressure compartment and moves to the decompression compartment is measured with a gas detector.

  In a preferred embodiment of the present invention, the internal space of the container to be measured may be a decompression compartment.

  In another preferred embodiment of the present invention, the granular material may have a circumscribed sphere diameter of 0.05 mm or more and 10.0 mm or less, and may have a spherical shape. The granular material may be made of metal.

  The present invention described above, preferred embodiments of the present invention, and components included in these can be implemented in combination as much as possible.

  Since the gas permeation measurement method according to the present invention includes a step of filling the vacuum compartment with particulate matter in combination with the step of specifying another invention, even if the pressure in the vacuum compartment is reduced after the step. The container under measurement does not deform. For this reason, it is possible to perform a gas permeation measurement that permeates the entire measured container including the bottom surface portion, the side wall portion, the inlet / outlet attachment portion and the inlet / outlet portion of the measured container, and to measure the gas permeation as the entire container. There is an advantage that the value is obtained. Further, since the container to be measured is not deformed, the measured value is a highly reliable gas permeation measuring method with good reproducibility. Furthermore, there is an advantage of a measurement method that makes full use of the detection capability of the detector, as in the case of gas permeation measurement by a differential pressure method such as a film.

  Since the gas permeation measuring device according to the present invention is filled with the particulate matter in the decompression compartment together with the matters specifying other inventions, even if the pressure in the decompression compartment is reduced, the measurement container is not deformed. Does not occur. For this reason, it is possible to perform a gas permeation measurement that permeates the entire measured container including the bottom surface portion, the side wall portion, the inlet / outlet attachment portion and the inlet / outlet portion of the measured container, and to measure the gas permeation as the entire container. There is an advantage that the value is obtained. In addition, since the container to be measured is not deformed, the measured value is a gas permeation measuring device with good reproducibility and a highly reliable measured value. Furthermore, as with a gas permeation measuring device using a differential pressure method such as a film, there is an advantage of a measuring device that fully utilizes the detection capability of the detector.

FIG. 1 is an explanatory diagram of a gas permeation measuring apparatus 1.

  Hereinafter, a gas permeation measuring method for a container and a gas permeation measuring apparatus for a container according to an embodiment of the present invention will be further described with reference to the drawings. In order to facilitate understanding of the present invention, some drawings referred to in this specification are schematically illustrated by exaggerating some components. For this reason, the dimension, ratio, etc. between components may differ from a real thing. Further, the dimensions, materials, shapes, relative positions, etc. of the members and parts described in the embodiments of the present invention are not intended to limit the scope of the present invention to those unless otherwise specified. It is merely an illustrative example.

  FIG. 1 is an explanatory diagram of a gas permeation measuring apparatus 1.

  The container 2 to be measured is positioned inside the measurement chamber 21. A sealing plug 12 is attached to the entrance / exit of the container 2 to be measured. The sealing stopper 12 is a stopper provided with a property that the internal decompression state of the measurement container 2 is maintained even when the measurement container 2 is evacuated. Further, the sealing plug 12 is attached to the measurement container so that the internal decompression state of the measurement container 2 is maintained even when the measurement container 2 is evacuated.

  A long pipe 17 and a short pipe 18 pass through the sealing plug 12. The long pipe 17 is connected to the evacuation pipe 13 via a connector / water inlet 16. An open / close valve 15 is attached to the end of the short pipe 18. During the gas permeation measurement, the on-off valve 15 is closed.

  In the present invention and the present specification, the vacuum means a low pressure state necessary for gas permeability measurement using the measurement principle of the differential pressure method.

  Here, the measurement principle of the differential pressure method is that the test gas positioned in the atmospheric pressure compartment, with one being the atmospheric pressure compartment and the other being the decompression compartment across the object to be measured, Is measured by measuring the transferred test gas. The value of vacuum or reduced pressure is a value that is appropriately determined according to the test gas permeability of the object to be measured. An example of the vacuum or reduced pressure value is 1 Pa (Pascal) to 100 Pa.

  The evacuation pipe 13 is connected to the long pipe 17 and is electrically connected to the internal space 5 of the container 2 to be measured. The long pipe 17 passes through the wall surface of the measurement chamber 21, reaches the outside of the measurement chamber 21, is connected to the vacuum pulling pipe 13, and passes through the first valve 41, the measuring pipe 14, and the second valve 42 to the vacuum pump 31. linked.

  An example of a vacuum pump is an oil diffusion pump.

  The gas permeation measuring apparatus 1 illustrated in FIG. 1 includes a gas chromatograph 32 that is a gas detector. The flow path system related to the gas chromatograph includes a carrier gas cylinder 33, a third valve 43, a second flow path 47 and a fourth valve 44. The third valve 43 is connected to the first valve 41 via the first flow path 46. The fourth valve 44 is connected to the second valve 42 via the third flow path 48.

  By operating the first valve 41, the second valve 42, the third valve 43 and the fourth valve 44, the measuring pipe 14 is connected to the flow path system related to the gas chromatograph and is disconnected.

  Any container can be used for the container 2 to be measured without any particular limitation. Examples of preferred containers to be measured include containers that allow the contents to be squeezed together with the containers, PET bottles designed to easily crush empty containers, PET bottles for liquid beverages, bottles for subdividing liquids and fluids, and the like. Further, a container to be measured having a shape in which the entrance / exit portion is narrowed with respect to the container body is preferable. This is because it is easy to attach the sealing plug 12 and it is easy to design and manufacture the sealing plug itself. Examples of preferable container materials as the container to be measured include polyethylene (PE), polypropylene (PP), nylon, a multilayer structure thereof, and polyethylene terephthalate (PET).

  The granular material 11 is filled in the internal space 5 of the container 12 to be measured. The granular material 11 plays a role of protecting the wall surface of the measurement container from deformation against a force that deforms the wall surface of the measurement container due to a pressure difference between the outside and the inside of the measurement container 12.

  The role of the granular material 11 is specifically illustrated by the illustrated gas permeation device 1. The container 12 to be measured is a PET bottle filled with 500 ml of drinking water and commercially available as a container and drinking water. When the container 12 to be measured is empty and the outside of the container 12 to be measured is maintained at atmospheric pressure, and the internal space of the container 12 to be measured is depressurized, the pressure difference between the outside and the inside of the container 12 to be measured The wall 12 receives a force in the direction from the outside to the inside, and the container 12 to be measured is crushed.

  The inner wall 3 of the container 12 to be measured comes into contact with the granular material 11 at a number of points, and at the same time, the granular material 11 comes into contact with the individual granular materials, and counteracts the force that deforms the wall surface caused by the pressure difference. Therefore, the measured container 12 filled with the granular material is not crushed even if the internal space is decompressed.

  In addition, the granular material 11 contacts the inner wall 3 of the container to be measured at a point or a small area. For this reason, the wall permeation of the test gas to the measurement container is not affected by the presence or absence of the granular material 11. The granular material 11 uses a granular material that does not absorb the test gas. And the granular material 11 shall be rich in rigidity. This is to play a role of protecting the wall of the container to be measured from deformation.

  In the present invention and this specification, the wall surface of the container to be measured means a surface constituting the entire container to be measured including the bottom surface portion, the side wall portion, the entrance / exit attachment portion and the entrance / exit portion of the container to be measured. Moreover, an inner wall means the inner surface of a wall surface.

  The granular material 11 is preferably made of metal or glass. Moreover, the granular material which coat | covered the synthetic resin, wooden, and ceramic granular material with the metal is also preferable. This is because they do not absorb the test gas. The metal may be a metal composed of a single element or an alloy. Examples of the metal composed of a single element include aluminum, nickel, gold, silver, platinum, copper, and iron. Examples of the metal that is an alloy include steel, stainless steel (eg, SUA304, SUS403, SUS430, etc.), brass, and white copper. Examples of the glass include soda glass, borosilicate glass, and sapphire glass.

  The shape of the granular material is a sphere, an elliptic sphere, a regular polygon, a polygon, an indefinite shape, or the like. Of these, spherical shapes are preferred. This is because the inner wall of the container to be measured is in contact with the point.

  The radius of the circumscribed sphere is usually 0.05 mm or more and 10 mm or less, preferably 0.1 mm or more and 5.0 mm or less, more preferably 0.1 mm or more and 1.0 mm or less. Within this size range, it may be determined by trial and error in consideration of the capacity of the container to be measured, the thickness of the wall surface, the material, the dimensions of the entrance / exit.

  For example, in the case of a PET container of beverage liquid (water, soft drink, green tea, black tea, seasoning liquid, etc.) with a capacity of 100 ml to 2000 ml, a circular cross section and a radius of 6 mm to 15 mm, the outer circumference of the granular material The radius of the sphere is preferably from 0.1 mm to 1.0 mm.

  A test gas 24 is filled in the indoor space 23 of the measurement chamber 21. The indoor space 23 is a space surrounded by the measurement indoor wall 22, the measured container outer wall 4, and the outer wall surface of the sealing plug. The measurement chamber 21 has a test gas inlet 25 and a test gas outlet 26. If the test gas 24 continues to flow from the test gas inlet 25 to the indoor space 23 for a certain time, the indoor space 23 is filled with the test gas 24. Alternatively, the internal space 5 of the container 2 to be measured may be depressurized, and the test gas 24 may be continuously supplied from the test gas inflow port during the gas permeation test.

  The test gas 24 is, for example, oxygen gas, water vapor, carbon dioxide gas, or nitrogen gas.

  In the gas permeation measuring apparatus 1 illustrated in FIG. 1, the indoor space 23 is the atmospheric pressure compartment 7 and is filled with the test gas. The normal pressure compartment 7 is maintained at atmospheric pressure.

  On the other hand, by operating the first valve 41 and the second valve 42, the internal space 5, the long pipe 17, the vacuum pipe 13, and the measuring pipe 14 of the container to be measured 2 are connected to the vacuum pump 31, and the internal space 5, long The pipe 17, the vacuum pipe 13, the first valve 41, the measuring pipe 14 and the second valve 42 are evacuated. When the predetermined vacuum value is reached, the second valve 42 is operated to disconnect the system path from the internal space 5 to the measuring pipe 14 and the vacuum pump 31. In the gas permeation measuring apparatus 1, the internal space 5 is a decompression compartment 6.

  The step of positioning the test gas in the normal pressure compartment and the step of reducing the pressure in the decompression compartment may be reversed, or both may be performed in parallel. When the container to be measured permeates a relatively large amount of test gas, the step of positioning the test gas may be performed after the step of depressurization.

  Hold this state for a certain period of time. The test gas permeates the measured container wall and reaches the internal space 5, and the concentration of the test gas becomes constant in the system path from the internal space 5 to the measuring pipe 14. The certain time is, for example, several minutes to several days.

  Next, the first valve 41, the second valve 42, the third valve 43, and the fourth valve 44 are operated to connect the measuring pipe 14 to the gas chromatograph flow path. As a result, the carrier gas passes from the cylinder 33 through the first flow path 46 to the measuring pipe 14 and is introduced into the gas chromatograph 32 through the third flow path 48 together with the test gas existing in the measuring pipe 14. The introduced test gas is quantified by the gas chromatograph 32.

  The gas detector is not limited to a gas chromatograph, and may be an individual gas concentration meter (oxygen gas concentration meter, carbon dioxide gas concentration meter, etc.) corresponding to the test gas. A gas chromatograph is preferred. This is because, in general, the minimum detected concentration is small, it is possible to cope with different test gases, and multi-component gases can be measured simultaneously.

  The internal space volume of the container to be measured (the volume excluding the volume of the granular material) is obtained separately. For example, with the container to be measured filled with particulate matter, fill the internal space with water, weigh the entire container to be measured, and determine the difference from the weight of the container to be measured containing particulate matter without water. Then, the volume may be calculated.

  Specifically, the connector / water inlet 16 is removed, the measured container 2 and the vacuum pipe 13 are disconnected, the open / close valve 15 is opened, and the internal space of the measured container 2 from the connector / water inlet 16 is opened. Fill the container with water and weigh the entire container to be measured.

  The decompression compartment and the normal pressure compartment in the measurement chamber may be reversed. That is, the internal space of the measurement container may be a normal pressure compartment, and the indoor space surrounded by the measurement chamber wall and the measurement container outer wall may be a decompression compartment. The test gas is positioned in the atmospheric pressure chamber, and the decompression chamber is filled with particulate matter and depressurized.

  Although one embodiment of the present invention has been described in detail with reference to the drawings, a specific configuration example is not limited to this one embodiment, and the design can be changed without departing from the gist of the present invention. Are included in the present invention.

1 Gas permeation measuring device
2 Container to be measured
3 inner wall of the container to be measured
4 Container outer wall to be measured
5 Internal space
6 decompression compartment 7 normal pressure compartment 11 granular material 12 sealing plug 13 vacuum pipe 14 metering pipe 15 on-off valve 16 connector / water inlet 17 long pipe 18 short pipe 21 measurement room 22 measurement room wall 23 room space 24 test Gas 25 Test gas inlet 26 Test gas outlet 31 Vacuum pump 32 Gas chromatograph as gas detector 33 Carrier gas cylinder 34 Data processing device 41 First valve 42 Second valve 43 Third valve 44 Fourth valve 46 First flow path 47 Second channel 48 Third channel

Claims (10)

A gas permeation measuring method for measuring a gas permeation amount of a container to be measured, comprising the following steps.
A. By positioning the container to be measured inside the measurement chamber, one space of the inner space of the container to be measured and the indoor space surrounded by the inner wall of the measurement chamber and the outer wall of the container to be measured is a decompression compartment, and the other space is at normal pressure. B. This is a step of filling the decompression compartment with particulate matter, and the particulate matter protects the measurement container from deformation against the force that deforms the measurement container wall surface caused by the pressure difference between the measurement container and the measurement container. Is,
C. Positioning the test gas in the normal pressure chamber; d. Step of reducing the pressure in the decompression compartment e. The step of measuring the test gas that has permeated through the wall of the container to be measured and has reached the decompression compartment after passing through the steps c and d. The gas permeation measuring method according to claim 1, wherein the internal space of the container to be measured is a decompression compartment. The gas permeation measuring method according to claim 1 or 2, wherein the particle has a circumscribed sphere diameter of 0.05 mm or more and 10.0 mm or less. The gas permeation measuring method according to any one of claims 1 to 3, wherein the granular material is spherical. The gas permeation measuring method according to any one of claims 1 to 4, wherein the granular material is made of metal. In the gas permeation measuring device for measuring the gas permeation amount of the container to be measured,
Consists of measurement chamber, granular material, vacuum pump, test gas and gas detector,
The container to be measured is positioned inside the measurement chamber,
One space of the inner space of the container to be measured and the space surrounded by the inner wall of the measurement chamber and the outer wall of the container to be measured is a decompression compartment, and the other space is a normal pressure compartment,
The decompression compartment is filled with particulate matter, and the particulate matter protects the measured container from deformation against the force that deforms the measured container wall surface caused by the pressure difference between the measured container and outside the measured container.
The vacuum pump is connected to and disconnected from the decompression compartment,
The test gas is positioned in the atmospheric pressure compartment,
A gas permeation measuring device for a container to be measured, in which a test gas which is reduced in pressure in the decompression compartment and passes through the wall of the container to be measured from the normal pressure compartment and moves to the decompression compartment is measured by a gas detector. The gas permeation measuring apparatus according to claim 6, wherein the internal space of the container to be measured is a decompression compartment. The gas permeation measuring device according to claim 6 or 7, wherein the particle has a circumscribed sphere diameter of 0.05 mm or more and 10.0 mm or less. The gas permeation measuring apparatus according to any one of claims 6 to 8, wherein the granular material is spherical. The gas permeation measuring apparatus according to any one of claims 6 to 9, wherein the granular material is made of metal.

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