JPH0648226B2 - Inspection method for sealed containers - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for inspecting a sealed container.

In particular, it is a sealed medical container such as an infusion container (drip container) and an injection solution container (ampoule), and is a few μm so that the contents will not change at all even when stored for many years such as around 5 years. It relates to the inspection of the sealing failure of the sealed container that requires a high degree of sealing property that does not allow the existence of pinholes of the order of several tens of μm. Poor sealing caused by perfection, or pinholes or the like in the container itself that exist regardless of the seal.

Therefore, in this specification, the term "sealing failure part" means a sealing failure part or a pinhole.

Further, in this specification, the term "sealed container" means not only a "hard container" that maintains a certain shape even when liquid is not contained therein, but also a solid container when liquid is not contained inside. It also includes items such as "soft bags" that do not maintain their shape.

<Prior Art> As an inspection method of this type, for example, JP-A-60-90 is used.
118, JP-A-60-204431, JP-A-60-
No. 204431, 59-74030, and 5
9-124246, JP-A-59-124247, JP-A-58-193237, JP-A-58-193238.
JP-A-58-193239, JP-A-58-193
No. 240 or Japanese Patent Application No. 62-215219.

<Problems to be Solved by the Invention> In these conventional techniques, for example, Japanese Patent Application No. 62-21521.
Although the inspection method based on the difference in the degree of vacuum shown in No. 9 is quite accurate, it is difficult to set and maintain a certain degree of vacuum, or the amount of change in the degree of vacuum due to leaking gas, etc. Only pinholes can be detected.

However, the detection of pinholes in the order of 60 μ is still insufficient because it is required to detect those on the order of several μ as described above.

Therefore, the present invention intends to provide an inspection method capable of detecting even smaller pinholes.

<Means for Solving the Problem> Specifically, the present invention is based on a thermal image of a pinhole portion in which the temperature is partially greatly reduced by rapidly vaporizing the leaked liquid, for example, an image captured by infrared rays. It was made based on the discovery of the principle that it is possible to microscopically magnify and inspect by detecting, by first keeping the sealed container in a vacuum chamber whose vacuum degree is below a certain degree for a predetermined time. By leaking the filled liquid from the poorly sealed portion to the outer surface of the sealed container due to the vacuum atmosphere and rapidly vaporizing the leaked liquid in the vacuum atmosphere, the temperature of the outer surface portion of the poorly sealed portion is partially reduced. Then, the sealed container is taken out of the vacuum chamber, and while the temperature of the outer surface portion of the poorly sealed portion is partially lowered, By capturing a thermal image of the outer surface of the sealed container is made so as to detect a sealing defect portion.

<Operation> A feature of this method for inspecting a sealed container is that a defective sealing portion is detected by a thermal image having temperature unevenness due to liquid leaking from the defective sealing portion.
In order to improve the inspection accuracy, that is, in order to make it easier to capture the poorly sealed portion in the thermal image, a vacuum process is performed to promote the leakage of the liquid from the poorly sealed portion and the vaporization of the leaked liquid. Is a major feature.

<Embodiment> An embodiment of the present invention will be described below in order with reference to the drawings.

Item to be inspected The item to be inspected in this embodiment, that is, the sealed container 1, is
They are a medical drip container 1t, an injection solution ampoule 1a and the like as shown in the figure.

The drip container 1t is made of soft plastic and has a mouth 2 on one side.
But a flat "soft bag" with a seal 3 on the other side
And is relatively large, for example, 24 cm × 13 cm.

The injection liquid ampoule 1a is a "hard container" type and has a seal portion 4 at the tip, which is a relatively small cylindrical shape such as 2.5 cm Φ x 7 cm, and is usually a unit of several tens, for example, a carton. Place it in a (ball box) or place it on a tray (sink) for processing.

After the sealing process is completed, these hermetically sealed containers 1 are subjected to an appropriate treatment so that the surface of the hermetically sealed container 1 does not have any adhering moisture, and are supplied to the next vacuum treatment process.

Vacuum treatment The sealed container 1 to be inspected is held in a vacuum chamber 6 having a vacuum degree of a certain level or less for a predetermined time and exposed to a vacuum condition.

As a result, if the hermetically sealed container 1 has a poorly sealed portion, for example, a pinhole, the liquid in the hermetically sealed container 1 is sucked out from the pinhole by being sucked under the condition of vacuum, and leaks out.

Here, the sealed container 1 is inverted during the vacuum processing. That is, since there is a void portion 7 in the sealed container 1, the void portion 7 may hit a portion having a pinhole unless it is inverted, and the liquid may not leak despite the presence of the pinhole.

Then, the leaked liquid is rapidly vaporized in a vacuum atmosphere, and in that case, a large amount of latent heat of vaporization is taken away in accordance with the rapid vaporization, so that the temperature of the outer surface portion of the sealed container 1 is largely reduced.

As can be seen from the above description, one of the purposes of the vacuum processing is to promote the leakage of the liquid from the pinhole. Therefore, the condition of the vacuum processing, that is, the exhaust speed in the vacuum chamber 6 is the inspection accuracy, that is, the inspection target. It depends on the size of the pinhole to be obtained, and is specifically determined according to the required inspection conditions, that is, the inspection accuracy, the inspection speed, and the like.

In addition, the treatment time is related to the inspection accuracy in the range related to the leak amount of the liquid, but at the same time, it is related to the change in the temperature distribution on the outer surface due to the leaked liquid, and if it is too long, the temperature difference is averaged. Therefore, it is decided based on the balance between the two.

This vacuum processing may be slightly different depending on the type of the sealed container 1, and this point will be described below.

In the case of the drip container 1t, since it is relatively large, it is usually processed individually. However, in consideration of the inspection speed, a plurality of vacuum chambers 6 are accommodated and processed simultaneously. Further, since the drip container 1t is soft, by applying external pressure, it is possible to further promote the leakage of the liquid in addition to the vacuum suction, and to obtain higher inspection accuracy.

As a method of external pressurization, for example, a method in which the drip container 1t is mechanically pressed when the vacuum chamber 6 is closed, or a method in which the drip container 1t is pressed by an air bag that expands according to the pressure reduction in the vacuum chuck 6 is used. Can be considered.

In the case of the injection ampoule 1a, as described above, it is placed in a carton or placed on a tray for processing.
For example, when treating in carton units, the leaked liquid adheres to the outer surface of each injection liquid ampoule 1a and simultaneously to the carton, thereby lowering the temperature of the site.

Thermal Image Inspection When the predetermined vacuum processing is completed, the sealed container 1 in which the temperature of the outer surface portion of the pinhole portion is partially lowered is taken out from the vacuum chamber 6 and its thermal image is captured. Specifically, the infrared imager 8 is used to capture a thermal image.

As is well known, the infrared imager 8 captures an image by infrared rays radiated from the outer surface of the object, and represents the temperature distribution state of the outer surface of the object as a thermal image with gradation according to the temperature. It is possible.

Therefore, when the infrared imager 8 captures a thermal image of the sealed container 1 as described above, a pinhole portion having a lower temperature than the surroundings can be captured as an image with a gradation different from that of the surroundings.

Of course, this "capturing as an image" does not have to be an actual visual image, that is, an image by a monitor, but it is also possible to take in as mere data and automatically determine the presence of a pinhole.

To describe the resolution, an example of the currently possible resolution is obtained by combining 256 gradations and a temperature resolution of 0.1 ° C., and specifically, 0.1 × 2.
A difference of 0.1 ° C. can be detected in the range of 56 = 25.6 ° C. That is, when the surface temperature of the sealed container 1 is around X ° C., the observation temperature range of the infrared imaging device 8 is X-12.
By setting the temperature in the range of 8 ° C. to × + 12.8 ° C., it is possible to obtain a portion having a difference of 0.1 ° C. as an image with a gradation corresponding to each of the temperatures falling within this range.

The individual sealed containers will be described below.

In the case of the injection liquid ampoule 1a, as described above, when processing in carton units, a low temperature portion due to the leaked liquid also occurs in the carton, so it is more preferable to take a thermal image of the carton as well.

In addition, depending on the conditions such as the manufacturing method, the thickness of the container, the type of material resin, etc., there is no pinhole in the container itself, because only the defective seal at the seal part needs to be inspected. The inspection purpose can be sufficiently achieved by inspecting only the side having the seal portion. Therefore, if the injection liquid ampoule 1a corresponds to such a case, in this case, it is more preferable to perform the inversion during the vacuum processing and the inversion during the thermal image inspection described above. Inverting is not always necessary if the liquid is allowed to go to.

In the case of the drip container 1t which is a “soft bag”, normally,
Since it is possible that there are pinholes in the container itself, it is necessary to inspect the entire surface at all times, and the inversion as described above is always performed so that thermal images of the front and back are taken.

Selection of good / defectives Depending on the existence of pinholes, they are classified as good / defective. Good products are passed on the line as they are, and subsequent processing is continued, and defective products are eliminated from the line.

This good / bad separation may be performed visually by using a monitor image, but it is more preferable that the thermal image is captured as data and automatically processed by a computer as described above.

The size of the pinholes that could be detected by the above treatment was about 30 μm, whose size could be confirmed. In the case of this 30 μ pinhole, a temperature difference of about 4 to 5 ° C., which is several tens of times the resolution described above, was obtained.

However, this is not because the size of 30μ is not the limit, but it is simply because it is very difficult to artificially form a pinhole having a size smaller than 30μ. From the above-mentioned clarity of the leaked state of the liquid and the thermal image and the indirect experiment conducted in connection therewith, it is possible to sufficiently detect even pinholes of 10 μm or less.

<Effects of the Invention> The method for inspecting the sealed container according to the present invention, as described above, promotes the leakage of the liquid from the poorly sealed portion by the vacuum treatment and rapidly vaporizes the leaked liquid, The temperature of the outer surface of the poorly sealed part is greatly reduced, and the poorly sealed part is detected by capturing a thermal image in this state. Will be detected, for example, several μs required for medical sealed containers
There is an excellent effect that a sealing failure such as the following pinhole can be detected.

[Brief description of drawings]

FIG. 1 is a flow chart showing the flow of the method for inspecting a sealed container according to the present invention. 1 ... Sealed container 6 ... Vacuum chamber 8 ... Infrared imager

Claims (2)

[Claims] 1. First, the sealed container is held in a vacuum chamber having a vacuum degree of a certain level or less for a predetermined time so that the filled liquid leaks to the outer surface of the sealed container from a poorly sealed portion due to a vacuum atmosphere. By rapidly vaporizing the leaked liquid in a vacuum atmosphere, the temperature of the outer surface portion of the poorly sealed portion is partially lowered, and then the sealed container is taken out from the vacuum chamber and the temperature of the outer surface portion of the poorly sealed portion is reduced. A method for inspecting a sealed container, which detects a defective sealing portion by capturing a thermal image of the outer surface of the sealed container while the partially lowered state is maintained. 2. The method for inspecting a sealed container according to claim 1, wherein external pressure is applied to the sealed container in the vacuum chamber.