JPH02138845A - Inspection of leak through sealed container or the like - Google Patents

Abstract

PURPOSE:To enable inspection of leak in gaseous phase and solid phase unable to observe with naked eyes by making an internal pressure higher than a pressure of an atmosphere. CONSTITUTION:An internal pressure of a sealed container or the like is made higher than a pressure of an atmosphere of a fluid to give the sealed container leak conditions and a difference in refractive index between a leak substance from the container and a atmospheric liquid is visualized to monitor. This enables inspection of a leak through the container.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of testing for leakage from a sealed container or package.

Problems with the Prior Art Sealed containers have been used for storing articles for a long time. In addition, hermetically sealed packaging bodies for storing articles while insulating them from the outside world have also been known for a long time. In a sealed container or sealed package,
In the past, glass and metal were the mainstream materials for packaging materials (referred to as sealed containers, etc.). Currently, materials such as plastic, thin metal plates, metal foil, or laminated materials such as plastic, metal foil, and paper are being used. In addition to ampoules of injectables, sealed glass containers etc. are used to enclose injectables, drugs, reagents, microorganisms, food, drinking water, cosmetics, etc., and are sealed with rubber or plastic stoppers. There are bottles etc.

Examples of sealed metal containers include canned containers, gas cylinders, spray containers for paints, chemicals, cosmetics, etc., and separate containers for drinking water and the like. Plastic sealed containers etc. include drugs (ampoules, infusion bottles, infusion bags, sachets, etc.);
There are foods (instant coffee, instant ramen, shaved bonito flakes, seaweed, etc.), drinking water, cosmetics, and cylinders (lighters, etc.). Sealed containers made of laminated materials made by laminating plastic with metal foil and/or paper include food (retort foods such as curry sekihan, bags for seasonings, furikake, etc.), boxes for drinking water, etc. There is.

Furthermore, as a sealed package using laminated material of metal foil and plastic sheet, PTP with tablets encapsulated is used.
There are packaging etc.

There are various contents that are sealed and packaged, but they are in the gas phase,
It is a liquid phase, a solid phase, or a mixture thereof.

Some substances in the gas phase are easily soluble in liquids, while others are difficult to dissolve. Also, gas phase substances may be liquefied. Some liquid phase substances are easily vaporized, while others are difficult to vaporize. There are also cases where the liquid phase is a solution of a substance that is easily crystallized. Some solid-phase substances sublimate easily, while others do not sublimate. Also, some solid phase substances are easily soluble in liquids, while others are not.

Furthermore, the solid phase substance may be uniform in size or non-uniform in size. Additionally, some of the contents may be heat stable while others may be unstable.

Also, some substances chemically react easily with other substances, while others do not react easily. Furthermore, some things are easily fermented and putrefied by microorganisms, while others are not fermented or putrefied.

In order to enclose these contents in a sealed container, treatments such as filling with various gases, pressurization, depressurization, vacuum, heating, sterilization, sterilization, drying, and various other processing are performed.

Therefore, even if there is an extremely small capillary pinhole in a sealed container, the contents will not only evaporate, sublimate, disappear, dissolve, change in quality, and be contaminated, but also impair commercial value.
In the case of sealed containers for chemicals and combustible materials, problems of fire and environmental pollution may occur, and in the case of sealed containers for food and medical products, serious problems may arise that could threaten the lives of consumers and patients. .

Therefore, these products are inspected and controlled very strictly from production to shipment. In addition, detection of capillary pinholes created during distribution and storage is also possible.
Various methods were used, but none of them were perfect.

For example, as a leakage testing method on the side of ampoule producers, a method is known in which capillary pinholes are detected by arranging a pair of electrodes close to the ampoule and applying a voltage between them. This method can be incorporated into a production line to perform 100% inspection, and has achieved excellent results, but as it is an electrical detection method, it is an absolute prerequisite.
The packaging container must be made of electrically insulating material and the contents must be electrically conductive, which limits the items to be inspected. Furthermore, since a high voltage is used, if the packaging container has a weak withstand voltage strength, dielectric breakdown will occur, and if the voltage is lowered, the detection range will become narrower. Furthermore, if the contents are flammable, there is a risk of fire, so they cannot be used.

Additionally, if the sealed container does not have self-shape retention, it is extremely difficult to prepare electrodes that are compatible with all deformed shapes, resulting in undetectable areas and making it impossible to inspect the entire circumference of the container. There are many things that cannot be done.

Another method of testing ampoules is to store them in a storage room for a certain period of time after production. If there are capillaries or pinholes, dried, solidified, or crystallized substances will be observed in those areas. Although this method is effective in finding extremely fine capillaries, it is time-consuming and cannot be incorporated into a production line. In addition, this method does not cause solid phase precipitation.
It cannot be applied to contents that are difficult to form.

In addition, as an inspection method for plastic containers, the 11th
In the Japanese Pharmacopoeia, [Place seven pieces of paper around the container,
Pressure the container (20℃, 0.7kg/am2.10 minutes)
and inspect the contents for leakage. ” is stipulated. However, such a method is not perfect and is not efficient. Moreover, it cannot be incorporated into the production line.

Another inspection method applicable to ampoules and PTP packages (hereinafter referred to as ampoules, etc.) is a dyeing method using a methylene blue solution. This method involves submerging a sealed container, etc. in methylene blue solution, allowing the methylene blue solution to enter through capillaries, pinholes, etc., and visually inspecting the coloring. There are two methods: vacuum dyeing method and pressure dyeing method. . Although this method allows for a full-circumference inspection, if a product contaminated with methylene blue is missed, there is a risk of injecting the patient with an injection solution contaminated with methylene blue solution. Furthermore, it cannot be applied to sealed packages with complicated structures in the sealing part, such as infusion containers (glass bottles, plastic bottles, plastic bags, etc.) and vials containing freeze-dried injections. This is because methylene blue solution adheres between the rubber stopper and the metal and plastic caps that cover it, making it difficult to clean completely and contaminating those parts.
This is because there is a risk of secondary contamination occurring when using the injection needle. Furthermore, this method is also not suitable for integration into a production line.

Infusion containers are changing from glass containers to plastic bottles that have relatively high shape retention, and are also beginning to change to flexible plastic bags that have low self-shape retention. When using glass or plastic containers, the rate of injection of the infusion decreases due to the decrease in the internal pressure of the container when administering the infusion.
Alternatively, it is necessary to introduce air into the container to prevent infusion, which may cause contamination of the infusion. Plastic bags solve this problem because they allow infusions to be injected without introducing air into the container. However, there has been no perfect method for inspecting capillaries and pinholes in such containers. The reasons for this are that many products have high electrical resistance, such as glucose or distilled water, and their detection reliability is low; the film of the plastic bag is thin, and dielectric breakdown occurs when high voltage is applied; Even if the shape is the same, the self-shape retention force is small, there are undetectable areas, and it is difficult to inspect the entire circumference. Therefore, it was necessary to rely on the above-mentioned method of testing exudation by applying pressure. This method takes time to inspect and is not practical for inspection to be incorporated into a production line.

The present inventors have proposed a leakage testing method that is applicable to all sealed containers, etc., regardless of the material of the packaging material of the sealed container, etc., and the nature of their contents, and that As a result of intensive research on inspection methods that have almost no oxidation, we have developed methods for visualizing refractive index differences, such as the Schlieren method and optical interferometry (Matsuhatsu Ender, Michelson, 1-Weimann interferometry, etc.), using sealed containers. I came up with the idea of using it for leak inspection. That is, the current manufacturing technology for sealed containers, etc. is extremely advanced, and therefore defects that occur in sealed containers, etc. are extremely fine capillaries or pinholes. Therefore, it was predicted that if leakage conditions were given to a defective sealed container, the leakage of contents could be visualized as a flow of leaked substances using these methods.

Schlieren method and optical interferometry itself have been known as means for visualizing fluid flow and differences in refractive index, but as far as the inventors know, this method cannot be used for leakage inspection of sealed containers, etc. was not carried out.

As a result of repeated experiments based on this idea, the inventors have completed the present invention.

Means for Solving the Problems In the present invention, when inspecting for leakage from a sealed container etc. in a gaseous or liquid phase fluid atmosphere, the internal pressure of the sealed container etc. is determined relative to the pressure of the fluid atmosphere. 1. Apply leakage conditions to the sealed container, etc., and monitor leakage from capillaries and pinholes in the sealed container, etc. in the fluid atmosphere using Schlieren method, optical interference measurement, etc. . Leakage of colorless, transparent gas, liquid, and solid phases that are difficult or impossible to observe with the naked eye can be visualized as visible images.

In order to monitor leakage from a sealed container or the like using the Schlieren method, optical interferometry, etc., it is necessary to allow the leakage phenomenon to continue for a sufficient period of time to detect the leakage. Factors that sustain the leakage phenomenon include the shape and dimensions of the capillary and pin pole, the volume of leaked substances that can pass through them, viscosity, leakage pressure (differential pressure between the internal pressure of a sealed container, etc. and the external pressure of the surrounding fluid atmosphere), etc. It is. Therefore, it is best to ensure these factors appropriately.

To be more specific, methods for relatively increasing the internal pressure of a sealed container or the like compared to the fluid atmosphere pressure include the following methods.

1) Press the sealed container etc.

This method is the simplest when the sealed container or the like is deformable. However, the detection of leakage from the surface area of the container on which the compression means is acting may be impeded. In that case, change the area to apply pressure and
It is better to inspect in more than one process. Also, if there is a need,
It is also possible to perform multiple tests by changing the posture of the sealed container, etc., and changing the compression area.

Containers suitable for this method include plastic injection containers (plastic bottles and plastic bags, etc.), containers made of plastic or laminate materials such as metal foil paper (curry, red rice, etc.).
There are food items, shavings, seaweed, bags for seasonings, and beverage containers for milk, drinking water, etc.

However, this method is not applicable if the container is not deformable.

2) Heat the sealed container etc. from the outside.

3) Internally heat the contents in the container by electrical heating (resistance heating, dielectric heating, induction heating), etc.

4) The contents of the container are internally heated by irradiating light beams (infrared light, visible light, ultraviolet light) with a wavelength suitable for the contents of the container.

5> Apply ultrasound to internally heat the contents of the container.

Methods 2 to 5 above all expand the contents by heating the contents, thereby increasing the internal pressure. It is also possible to heat only selected substances within the contents.

Although these methods are relatively simple, they cannot be applied when the contents are unstable to heat, electromagnetic waves, light, ultrasound, etc. Furthermore, after heating the container in advance, the container may be positioned in the optical path in the schlieren method, optical interference measurement method, etc.; however, if necessary, it is possible to heat the container on the spot after setting the container in the optical path. can. If the atmospheric fluid is disturbed by the heat from the heating source or heated container during heating, use a glass container or chamber that is free of striae, bubbles, and distortion in the optical path of the Schlieren method, optical interferometry, etc. Disturbance of the atmospheric fluid can also be prevented by placing the atmospheric fluid in the chamber and raising the temperature of the atmospheric fluid.

The sealed container cannot be deformed, and the contents cannot be exposed to heat, electromagnetic waves,
If the atmospheric fluid is unstable to light, ultrasound, etc., 6) Reduce the pressure of the atmospheric fluid to a pressure lower than the internal pressure of the sealed container, etc.

In method 6 above as well, a glass vessel without striae, bubbles, or distortion is required.

It is best to reduce the pressure relatively quickly. These methods are difficult to apply, at least immediately after production, when the pressure inside the sealed container is reduced.

7) The sealed container is left in a relatively high pressure pressurized chamber for a certain period of time, and then returned to a relatively low pressure fluid atmosphere.

In this method, the sealed container cannot be deformed and the contents can be exposed to heat.
It can be applied to cases where electromagnetic waves, light, ultrasonic waves, etc. are unstable.

Thus, if there are capillaries or pinholes in the container, the contents will leak from those locations, and the flow of the contents in the fluid atmosphere can be monitored using the Schlieren method, optical interferometry, etc. .

Generally, when a liquid phase, a solid phase, or a mixed phase thereof is enclosed in a sealed container, it is difficult to seal the container without leaving any voids inside the container. Therefore, a gas phase generally exists within the sealed container, and therefore, it is only necessary to detect the leaking gas phase. However, for example, retort food, freeze-dried drugs, etc.
Depending on the contents, there may be almost no voids, and even if there are voids, those voids may be under reduced pressure.

In these cases, no or only a small amount of gas phase leaks, and there may be cases where substantially liquid phase, solid phase, or a mixture thereof leaks. Therefore, it is necessary to consider the relationship between the phase of the leaked substance and the phase of the atmospheric fluid.

Gas or liquid is used as the atmospheric fluid. A gas can be used as the atmospheric fluid if the leaking substance is a gas or is accompanied by a detectable amount of gas (ie, a liquid phase, a solid phase, a gas phase with a mixture thereof). It is advantageous to select the ambient fluid such that the difference in refractive index between the leakage fluid and the ambient fluid for the detection light is large. If the leaked gas is accompanied by a relatively large amount of liquid or solid, it may be possible to monitor the liquid or solid with the naked eye without using the Schlieren method or optical interferometry; The state can be visualized more clearly by the Schlieren method, optical interferometry, etc. (e.g.
colorless, clear liquid, solid).

To increase the refractive index difference between the leaking gas and the atmospheric gas,
For example, if the leaking substance is air, nitrogen gas, etc., it is better to use helium gas, carbon dioxide gas, etc. However, helium gas is expensive, and when carbon dioxide gas is used continuously in large quantities, environmental pollution must be considered. It will be obvious to those skilled in the art that other gases may be used, and the appropriate gas may be selected as the ambient fluid depending on the leakage gas.

Even if the leaking substance and the atmospheric fluid are the same gas,
If the density difference is large enough, it may be detectable.

Note that even when the leaking substance is a liquid that easily vaporizes or a solid that easily sublimes, a gas can be used as the atmospheric fluid. It is also possible to reduce the pressure of the atmosphere to provide a condition that facilitates vaporization. In this case, the leaked liquid may be detected with the naked eye as a jet, mist droplets, or liquid droplets in the atmospheric gas, but a slight seepage is difficult to detect with the naked eye. Jets of them.

The state in which vaporized gas diffuses from mist droplets, liquid droplets, and the wet surface of a container can be clearly detected by the Schlieren method, optical interferometry, or the like. Jets, mist droplets, droplets, and liquid droplets can be observed with the naked eye, but these are also imaged at the same time.

For example, when the contents are a solution and a gas, solids precipitated from the solution may clog the capillary or pinhole. In places where there is such fear,
It is best to inspect the crystals before they crystallize, or to wash the sealed container with water, hot water, or other suitable solvent beforehand.

Furthermore, if the contents are a mixture of gas and solid (for example, nitrogen gas and shavings), the capillary or pinhole may be blocked by the solid. In such a case, of course, it is generally better to apply the leakage condition in a shocking manner, and it is also effective to apply it intermittently or in stages. Abrupt changes and intermittent changes facilitate detection.

If the leaked substance is a liquid (not accompanied by sufficient gas for detection)
In this case, it is preferable to use a liquid as the atmospheric liquid.

Even when the leaked substance and the atmospheric fluid are both liquids, it is advantageous to select the atmospheric liquid so that the difference in refractive index between the leaked liquid and the atmospheric fluid with respect to the detection light is large. Water is preferably used as the atmospheric liquid unless the content is water.

Furthermore, it is advantageous to use a liquid in which the leaked liquid reacts with the ambient liquid to produce turbidity or color development.

However, even if the leaking substance and the atmospheric fluid are the same liquid, if the density difference and temperature difference are large enough,
Detectable.

Furthermore, even when the contents are in the form of a slurry (a mixture of liquid and solid) such as potage, a liquid can be used as the atmospheric fluid.

When the leaking substance is a solid particle, it is accompanied by a gas phase or a liquid phase in most cases, but in the case where the leaking substance is substantially a solid particle (in the case where there is no sufficient gas or liquid phase for detection). Either a gas may be used as the atmospheric fluid, or a liquid may be used to slow down the speed of dispersion, sinking, and floating of solid particles, making detection easier. Of course, the refractive index difference is not detected in the case of leaks of colored liquids or opaque solids, but it is advantageous to be able to detect these leaks with the same means.

The outline of the present invention has been described above, and the present invention will be explained in more detail below through examples of the present invention.

Example The following items were prepared as sealed containers for the experiment.

1) A plastic infusion container whose leakage was detected by conventional methods; 2) Leakage detected by conventional electrical methods; leakage detected by crystallization of glucose at one site of the capillary by storage in a storage chamber; 3) Vial bottle in which leakage was detected by conventional method 4) Soy sauce sealed in a bag made of aluminum foil and plastic laminate material, 1-7 tokecap 5> Soy sauce sealed in a plastic bag We prepared the following equipment for experimenting with vinegar for sushi.

1) Schlieren method device (manufactured by Mizojiri Optical Co., Ltd., model 5LC-100) 2) CRT display device 3) A chamber made of a transparent plastic plate that airtightly covers the above schlieren device (a gas introduction hole is provided at the bottom of the chamber) , a lid was provided above, and the gas inlet hole was connected to the carbon dioxide gas cylinder) 4) A tightening rod was operated from the outside of the chamber to sandwich and support a sealed container, etc., and the container, etc. could be further compressed. 5) Glass container without striae, bubbles, or distortion 6) Infrared lamp and condenser lens (for heating) [Example 1] An infusion container filled with carbon dioxide gas without introducing carbon dioxide gas. Inside the diember, the above-mentioned pressing device was placed in the optical path of the sample station in the Schlieren method apparatus, and the infusion container was pressed while the CRT was not observed with the naked eye. A jet of carbon dioxide gas was observed as a dark image from the pinhole in the infusion container.

From this example, when the leaking gas is carbon dioxide gas (e.g. from a carbon dioxide gas cylinder, carbonated beverage, etc.), not only can air be used as the atmospheric fluid, but it is also possible to generally reduce the refractive index difference between the leaking gas and the atmospheric gas. It will be appreciated that by increasing the size, leak detection is possible.

[Example 2] An infusion container filled with alcohol and air was placed in the optical path of a sample station in a schlieren method device using the above-mentioned pressing device in a chamber into which carbon dioxide gas was not introduced, and the CRT was observed with the naked eye. While doing so, I put pressure on the infusion container. A jet of mixed gas of air and vaporized alcohol was observed as a dark image from the pinhole part of the infusion container.

It will be appreciated from this example that leakage of volatile and sublimable substances can be detected using air as the atmospheric fluid.

[Example 3] The air in the chamber was sufficiently replaced with carbon dioxide gas. When an infusion container filled with water and air was placed in the optical path of a sample station in a Schlieren method device and the pressure device was used to press the infusion container, a thin jet of air was seen as a bright image on the CRT.

From this example, it will be understood that leakage of air and a gas having approximately the same refractive index as air (for example, nitrogen gas) can be detected using carbon dioxide gas as the atmospheric fluid.

[Example 4] A glass container free from striae, bubbles, and distortion was filled with water, and a commercially available soy sauce pack for sashimi, which had been opened in a bottle using a needle, was gently placed therein. This glassware was placed in the optical path of the sample station entering the Schlieren apparatus, and the puck was pushed with a glass rod. A jet of soy sauce was observed as a dark image on the CRT.

[Example 5] A pinhole was made with a needle in a commercially available tomato ketchup pack enclosed in a laminate container made of aluminum and plastic. Water was poured into the glass vessel used in Example 4, and the above pack was gently placed therein. This glassware was placed in the optical path of the sample station in the Schlieren method apparatus, and the puck was compressed with a glass rod. A dark image of the tomato ketchup being pushed out and spreading was observed on the CRT.

[Example 6] The same operation as in Example 4 was performed, except that a plastic bag filled with vinegar for sushi with a pinhole punched with a needle was used. A state in which vinegar was gushing out and spreading was observed on the CRT.

[Example 7] Water and air were sealed in a plastic infusion container, the container was boiled in hot water for about 2 minutes, heated to about 40°C, and placed in a sample station of a Schlieren method device in a chamber into which carbon dioxide gas was introduced. placed in the optical path. A hazy airflow of warm carbon dioxide gas was generated around the container, and a bright image of the jet of air was observed from the pinhole.

[Example 8] Water and air were sealed in a glass vial, and the vial was capped with a thin rubber stopper with a pinhole.

Boil this glass container in hot water for about 2 minutes to warm it to about 50℃,
It was placed in the optical path of a sample station in a schlieren method device in a chamber into which carbon dioxide gas was introduced. A strong airflow of heated carbon dioxide gas was observed around the vial, and no air ejection was clearly observed.

When a test similar to the above was conducted, except that the temperature inside the chamber was heated to about 50° C. with a heater, the flow of carbon dioxide gas around the glass container was reduced, and a jet of air was clearly observed.

It will be understood from Examples 7 and 8 that leakage conditions can be provided by heating the sealed container or the like from the outside.

In addition, those skilled in the art will be aware of various other heating methods 9, such as resistance heating.

Electrical heating such as dielectric heating and induction heating, light beams (infrared visible,
It will be understood that ultraviolet) irradiation, ultrasonic heating, etc. can also be applied.

[Example 9] Although no leakage was detected by the electrical detection method, an ampoule of glucose solution in which leakage was discovered due to precipitation of crystals in the storage room was washed with warm water to dissolve and remove the glucose crystals. This ampoule is placed in the optical path of the sample station in the Schlieren method apparatus, and the bottom of the ampoule is intermittently irradiated with light from an infrared lamp, which is focused using a condenser lens. In a carbon dioxide atmosphere, air was pulsatingly ejected from the ampoule on the CRT.

[Example 10] Warm water at 45° C. was poured into the glass vessel used in Example 4. Turn the glucose ampoule used in the example upside down (
The ampule was placed in the optical path of the sample station in the Schlieren apparatus. Glucose solution was observed on the CRT spewing out from the lower end of the ampoule.

[Example 11] An experiment similar to Example 1o was conducted except that the core ampoule was placed in the opposite position (the fused portion of the ampoule was directed upward). The state in which fine air bubbles emerge from the upper end of the ampoule is C.
Observed on RT.

[Example 12] An infusion container filled with water and air was placed in a pressurized chamber at about 2 atmospheres (
It was kept under pressurized air for 48 hours.

The above-mentioned infusion container was placed in the optical path of the sample station in the schlieren method apparatus in a chamber into which carbon dioxide gas was introduced. A jet of air was observed as a bright image on the CRT from a pinhole in the infusion container.

From this example, it is possible to detect the leakage of air or a gas having an equivalent refractive index from an undeformable sealed container containing a substance unstable to heat, electromagnetic waves, light, ultrasonic waves, etc. be understood. It is clear that by appropriately selecting the mechanical strength of the sealed container etc., the applied pressure can be increased and thereby the pressurization time can be shortened.

In the above embodiment, the CRT screen was observed with the naked eye, but instead of observing optical information from the Schlieren method on the CRT, for example, the contrast between the brightness of the background and the leaked image can be converted into an electrical signal. You can also convert and monitor it. In this case, the accuracy and efficiency of the inspection can be improved by limiting the scanning area to inspect only a limited area around the sealed container or the like.

Such signal processing techniques are well known in electronics technology and will not be described in detail. In this way, monitoring can be performed unmanned. Furthermore, although a Schlieren method device was used in the above embodiments as a means for detecting the refractive index difference of the fluid, it is known in the art that an optical interference measurement device such as a Matsuhatsu Enda, Michelson, or Twyman interference measurement device can be used. It will be obvious to those who are familiar with it. Schlieren method equipment is a simple method for visualizing refractive index differences.
Optical interference measuring devices must use monochromatic light, are expensive, and are sensitive to external environments such as vibrations.
Preferably, a Schlieren apparatus is used.

In addition, in the above examples, leakage conditions are given to the sealed container, etc., but the sealed container, etc. itself may contain pressurized gas (for example, gas cylinders, gas lighters, paints, chemicals, cosmetics, etc.). (e.g. spray carbonated drinks, etc.), and when inspecting these, without giving leakage conditions,
Leakage can be detected simply by selecting the appropriate atmospheric fluid.

From the above experiments, it is clear that the method of the present invention can be used for leak testing of a wide variety of sealed containers.

Although the method of the present invention has been explained above through some examples, the present invention is not limited to these examples, and various modifications can be made without departing from the technical idea of the present invention. be.

Effect of the invention The main effects of the present invention are as follows.

1> It is not limited to the material, size, shape, or type of contents of the sealed container, and can be applied to leakage inspections of almost all sealed containers.

2) The entire circumference of sealed containers, etc. can be inspected instantly as a two-dimensional image.

3) Conventionally, many inspections that could only be done by sampling inspections due to problems such as detection accuracy and processing capacity, can now be incorporated into the production line as non-destructive, 100% inspections, which will improve the quality of products from producers. The receiver can be used for inspection.

4) Since the flow of sealed containers, etc. and leaked substances is monitored as a visible image, there are no oversights, and the locations of capillaries and pinholes can be confirmed. Therefore, this information can be used for repair and production methods in the production line of sealed containers, etc. You can provide feedback as information for improvement.

Visible images of leakage can be recorded, and the records can be used for production management.

Claims (1)

[Scope of Claims] [1] A method for inspecting leakage from a sealed container, etc. in a gaseous or liquid phase fluid atmosphere, comprising: a) comparing the internal pressure of the sealed container, etc. to the pressure of the fluid atmosphere; and (b) monitoring the difference in refractive index between the substance leaking from the sealed container etc. and the atmospheric fluid by visual imaging means. A method of testing for leakage from sealed containers, etc. [2] In the method according to claim 1, the leakage conditions include pressing the sealed container etc. from the outside, heating the sealed container etc. from the outside, and heating the sealed container etc. from the outside. resistance heating, dielectric heating,
Internally heating the contents of a sealed container, etc. by electric heating such as induction heating, heating the contents internally by irradiating the contents of the sealed container, etc. with light of a selected wavelength, and applying ultrasonic waves to the sealed container, etc. placing the sealed container in a fluid atmosphere whose pressure is lower than its internal pressure; placing the sealed container in a relatively high-pressure first fluid atmosphere; for a predetermined period of time and then placed in a second fluid atmosphere at a relatively low pressure, or by a combination of two or more thereof; A method for inspecting leakage from a sealed container, etc., characterized by: [3] In the method according to claim 1 or 2, the substance leaking from the sealed container etc. is substantially a gas, and the difference in refractive index between the leaking gas and the atmospheric fluid with respect to detection light is provided. A method for inspecting leakage from a sealed container, etc., characterized by: selecting and using the above-mentioned atmospheric fluid such that the [4] In the method according to claim 1 or 2, the substance leaking from the sealed container etc. is substantially liquid, and the refractive index of the leaking liquid and the atmospheric fluid with respect to the detection light is A method for inspecting leakage from a sealed container, etc., characterized by: selecting and using the above-mentioned atmospheric fluid so that the difference is large. [5] The method according to claim 1 or 2, wherein the substance leaking from the sealed container is substantially solid, and the atmospheric fluid is liquid. How to test for leaks from etc.