JPH0247474Y2 - - Google Patents

Description

[Detailed description of the invention] ≪Industrial application field≫ The present invention is applicable to a package in which food, etc. is wrapped in a package made of, for example, a synthetic resin film.
In order to suppress discoloration and spoilage of the food, etc., if carbon dioxide gas or a mixed gas containing oxygen, nitrogen, alcohol vapor, etc. is added to this packaging material,
The present invention relates to a device for inspecting whether the sealed gas is leaking from pinholes, cracks, or seal failures in the packaging material.

≪Conventional technology≫ Recently, in order to prevent food from spoiling, enclosing a mixed gas of CO ₂ and N ₂ or alcohol vapor has been frequently used, and in order to preserve the red color of raw meat, CO ₂
In addition to N ₂ and N 2 , O ₂ is also added as a filler gas, and in any case, CO ₂ in particular is being used extensively.

By the way, in the case of such food packaging containing gas, if the gas is leaked through pinholes in the packaging material, outside air will flow into the package, defeating the purpose of gas filling. If the food cannot be delivered quickly and is sent to the market as is, the food in question may become contaminated with airborne bacteria, leading to unexpected accidents.

Therefore, means for detecting the presence or absence of defects in the film used as the packaging material for packages have already been devised, but the conventional means is to sweep a metal brush, which serves as an electrode, over the surface of the package. Therefore, when there is a pinhole or the like, it is known to electrically detect the defect by making the electrode conductive through the contents of the package.

However, when using the above method, it cannot be detected unless the contents are in a conductive liquid or gel state and the packaging material is filled with it. is extremely difficult to detect.

Furthermore, as a conventional means, it has been proposed to apply a voltage between both ends of the package and detect the presence or absence of a discharge current at this time.

However, when using this method, the packaging material of the package must have high insulation properties, be clean, and be free of conductive printing, etc., and as a result, the inspection target material is considerably damaged. In addition to limitations, there are also deficiencies such as the need to dry the package as a pretreatment for inspection.

≪Problems that the invention aims to solve≫ This invention examines the defects of the conventional inspection means mentioned above, and forcibly leaks the sealed gas such as CO ₂ to the outside from defective points such as pinholes in the package. By measuring this leaked gas with a test gas concentration meter, the presence or absence of a defective part can be known reliably and quickly. The goal is to be able to detect even small defects with high reliability without any restrictions, and to eliminate the need for pretreatment such as drying.

≪Means for solving the problem≫ In order to achieve the above-mentioned object, the present invention provides a vacuum container with an opening/closing lid in which a package can be freely taken in and out, and a vacuum container with a lid closed by the operation of a suction pump. An intake air test piping system that allows air to be freely discharged from the test gas concentration meter to the outside air, and an intake pump operates to release outside air into the vacuum container with the lid open, and the test gas It is an object of the present invention to provide an apparatus for inspecting leakage of sealed gas in a package, which is equipped with a purge piping system that also branches the flow from the densitometer to the outside air.

<<Operation>> After the package to be inspected is placed in the vacuum container and the lid is closed, the intake air inspection piping system is opened and opened by manually or automatically opening and closing the first to fifth switches. No, if the suction pump is operated, the gas in the vacuum container will be discharged to the outside air via the gas concentration meter to be tested.

This reduces the pressure inside the vacuum container, so the pressure of the sealed gas inside the package becomes higher. Therefore, if there is a pinhole in the package, the sealed gas such as CO ₂ will leak out, and this will cause the above-mentioned When the gas passes through a gas concentration meter, the concentration of the CO ₂ , etc. is displayed, and from this it is possible to know if there is a leakage of the sealed gas.

Next, by manually or automatically opening and closing the first to fifth switches, the intake air inspection piping system is closed and the purge piping system is opened. Therefore, the outside air sucked into this can be released into the vacuum container with the lid open, thereby discharging and dissipating gas such as CO ₂ remaining in the container, and also releasing it from the gas concentration meter under test. Since the outside air is discharged into the outside air, all the gas enclosed in the purge piping system can be removed, thereby ensuring operation without showing erroneous test results.

<<Example>> The present invention will be described in detail with reference to the illustrated embodiment. In FIG. 1, 1 is a vacuum container with an opening/closing lid 1a, and a package A is covered with food or the like. Packaging B
A package D containing a sealed gas can be stored so as to be able to be taken in and out at will. In the figure, 1b indicates a sealing material between the opening/closing lid 1a and the vacuum container 1.

Here, for the vacuum container 1, its opening/closing lid 1
FIG. 2 shows one configuration for opening and closing a by power.

That is, the opening/closing lid 1a, which is made of metal or synthetic resin like the vacuum container 1, is connected to the base 1c.
The vertical guide rods 1d, 1d are fitted in such a way that they can be raised and lowered freely, and a drive screw 1e is installed from the center of the lid 1a, while a screw rod 1e for driving is installed in the upper end of the vertical guide rods 1d, 1d. A geared motor 1g and a drive gear 1h that meshes with the gear 1g' to rotate at a low speed are installed on the mounting top plate 1f, which is installed astride the mounting top plate 1f. The upper end screw portion 1e' of 1e is screwed together in a penetrating state.

Therefore, by driving and rotating the geared motor 1g in forward and reverse directions, the driving gear 1h rotates, which causes the driving screw 1e to move up and down, so that the opening/closing lid 1a guides the guide vertical rods 1d, 1d. As shown in the dashed line, the lid moves upward to be in an open state, or as shown in a solid line, it is in a closed state.

Next, in the present invention, as illustrated in FIG. 1, two systems, an intake air inspection piping system 2 and a purge piping system 3, are connected to the vacuum vessel 1.

First, to explain an embodiment of the intake air inspection piping system 2, the intake piping end 2a is connected to the vacuum vessel 1.
A first opening/closing lid 2b, an intake pump 2c, and a flow rate adjustment valve 2 are opened inward and are sequentially operated by a solenoid valve or an electric valve.
d, a flow meter 2e, and a gas concentration meter 2f for gas to be detected, such as CO ₂ , which is open to the outside air, are interposed in series.

Furthermore, in the illustrated example, a vacuum gauge 2e is connected between the first on-off valve 2b and the intake pump 2c, and 2g' indicates an electric contact that operates depending on the degree of vacuum as will be explained later. Also, between the intake pump 2c and the flow rate adjustment valve 2d, there is a branch discharge pipe 2i which can be freely opened to the outside air by a fourth on-off valve 2h.
is branched.

Next, to explain the purge piping system 3 shown in FIG.
Not only are the flow rate adjustment valve 2d, the flow meter 2e, and the gas concentration meter 2f to be tested interposed as common members with the piping system 2, but also the fourth opening/closing lid 2h and the flow rate adjustment valve 2d are interposed. A purge pipe 3d equipped with a third on-off valve 3c is branched from between, and the purge pipe 3d is opened into the vacuum container 1. Furthermore, in the illustrated example, when opening the opening/closing lid 1a, the vacuum container 1
An outside air communication pipe 4a equipped with a fifth opening/closing lid 4 is provided so that the inside can communicate with outside air, and the first to fifth opening/closing valves 2b, 3b, 3c, 2
h, 4 can be opened and closed automatically and appropriately by a separately prepared electric controller 5, but of course, all operations may be performed manually.

Further, the controller 5 controls the intake air inspection piping system 2 by the electric contact 2g' which is activated when the degree of vacuum of the vacuum gauge 2g reaches a predetermined value.
The operating state of the purge piping system 3 is automatically switched from the operating state of the purge piping system 3 to the operating state of the purge piping system 3.

Therefore, in order to inspect the sealed gas leakage of the package D using the above-mentioned apparatus, two steps, an intake process and a purge process, are repeated as follows.

That is, by operating the geared motor 1g using the controller 5, the opening/closing lid 1 is operated.
A is moved up and opened, but this upward movement is detected by a limit switch or the like (not shown) and automatically stopped, and a desired number of packages D are stored in the vacuum container 1 whose lid is kept open.

Simultaneously with the lid opening operation, the intake pump 2c and the gas concentration meter 2f to be tested are started by supplying power, the first on-off valve 2b is closed, and the second and third on-off valves 3
b and 3c are opened, and the fourth on-off valve 2h is closed, so that the purge piping system 3 is opened.

As a result, the intake pump 2c takes in outside air from the outside air introduction end port 3a, and releases the intake air to the outside air through the following path.

That is, 3b → 2c → | | | | →3c → 3d → 1 → outside air 2d → 2e → 2f → outside air Therefore, the sample gas concentration meter 2f and the sealed gas remaining in the piping are reduced by the sucked outside air. However, at the same time as being purged, most of the suction air flows into the vacuum container 1, and the gas sealed in the container can also be dissipated into the atmosphere.

The purge step as described above lasts for a required time set in advance by the controller 5, but the time may be determined by the capacity of the suction pump 2c and the vacuum container 1, and the purge step By completing the process, the inside of the piping system and the vacuum vessel 1
The gas inside is replaced, resulting in an initial state in which there is no sealed gas.

Next, the suction step begins, in which the opening/closing lid 1a is lowered and closed, and the first opening/closing valve 2b is closed.
is open, the second on-off valve 3b is closed, and the third on-off valve 3c is closed.
By closing the fourth on-off valve 2h and opening the fourth on-off valve 2h, the intake air inspection piping system 2 is opened, and the gas flow is as follows.

1 → 2a → 2b → 2c → ｜ ｜ ｜ → 2h → 2i → outside air 2d → 2e → 2f → outside air Therefore, since the inside of vacuum container 1 is depressurized, the amount of sealed gas C in packaging material A of packaging body D is The pressure becomes relatively higher than the outside, and as a result, if there is a pinhole or seal failure in the packaging material A, the sealed gas C will be forcibly drawn out from there.
Air mixed with CO ₂ and the like passes through the test gas concentration meter 2f by the intake pump 2c. Here, it is desirable that the suction pump 2c be large. For example, if the packaging is to be inspected one by one, the displacement will be about several minutes to 10 minutes. Since the appropriate flow rate for the flow rate is generally as small as about 1/min, the air is discharged from the branch discharge pipe 2i via the first on-off valve 2b, and the flow rate adjustment valve 2d is adjusted to allow only an appropriate amount of the flow to be tested. It is arranged to flow into the gas concentration meter 2f.

Also, the _CO2 concentration in the air is usually 0.03VOL%
(300ppm), whereas the sealed gas is, for example, to maintain the red color of raw meat, the mixed gas CO ₂ is 20ppm.
Since the concentration is extremely high at around 40%, even a small leak would cause a rapid rise in CO ₂ concentration.

Therefore, for example, a full case may contain several thousand ppm.
By using a CO ₂ concentration meter, it is possible to clearly detect the increase in the concentration of CO ₂ , but if you set the zero point of the CO ₂ concentration meter to the air and only indicate the increase, you can increase its sensitivity. It can be improved by several tens of ppm or more.
When approximately 100 ppm is detected, it is desirable to issue an alarm by closing an alarm contact (not shown).

Here, Figure 3 shows the results of measuring the concentration of CO ₂ by punching a needle hole in the packaging material and performing the above procedure for a package with a sealed gas containing 20% CO ₂ and 80% O ₂ . As is clear from the chart, the maximum value of 2000 ppm is reached in about 80 seconds.

Therefore, in this case, even if the alarm contact is closed at 200 ppm, a defect in the package can be detected within 10 seconds.

In addition, when the above-mentioned alarm device is attached, the device is connected to the controller 5 so that when the controller 5 receives a signal from the alarm device, it automatically moves to the next purge step. It is better to

When no alarm is issued, that is, when there is no defect in the package D, it is preferable that automatic transition to the purge step be performed by the following means.

That is, for example, when the scale of the vacuum gauge 2g indicates about -1000 mmAg, the contact 2g' is activated, and the controller 5 receiving the output signal from this causes the transition to be started, or the transition is started in advance. The timer is activated as the required time set in the controller 5 elapses.

In this way, the suction process begins; in this process, the opening/closing lid 1a first descends to the closed lid state;
As mentioned above, by the operation of the first to fifth on-off valves,
The intake air inspection piping system 2 is opened, and the intake pump 2c
As a result of this operation, the pressure inside the vacuum container 1 is reduced, and the two steps are thus repeated.

Here, if the end signal of the suction process is given to the controller 5 as described above, the process will move to the purge process again, but at this time, the fifth on-off valve 4 is closed as shown in the illustrated example. When the outside air communication pipe 4a is opened, the opening/closing lid 1 of the vacuum container 1 is opened.
The operation of opening a becomes easier.

In addition, as an inspection method, it is better to inspect a large number of packages as one block, and if a defective block is detected, to inspect each of these packages one by one, rather than inspecting each package one by one. This is a good idea as the rate is relatively low.

<<Effects of the invention>> Since the present invention is constructed as described above, by placing the package in a reduced pressure environment, it not only becomes possible to detect leaks of the sealed gas with high reliability, but also eliminates the purge step. This also completely eliminates malfunctions caused by residual gas, and also eliminates the need for the contents of the package to be a good electrical conductor or for the packaging material to have insulation properties. The scope of application is also greatly expanded compared to conventional means, and it can be adopted for various types of packaging.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the entire piping of the sealed gas leak testing device according to the present invention, Fig. 2 is a partially cutaway front view of the vacuum container shown in Fig. 1, illustrating the opening/closing means for its opening/closing lid, and Fig. 3 is a partially cutaway front view of the vacuum container shown in Fig. It is a chart showing changes in the indicated concentration of CO ₂ over time for packages inspected by the same device. 1... Vacuum container, 1a... Opening/closing lid, 2... Intake inspection piping system path, 2a... Intake piping end port, 2b...
First on-off valve, 2c...Intake pump, 2d...Flow rate adjustment valve, 2e...Flow meter, 2f...Test gas concentration meter, 2g...Vacuum gauge, 2h...Fourth on-off valve, 2i
...Diversion discharge pipe, 3...Purge piping system line, 3a...
...Outside air introduction port, 3b...Second on-off valve, 3c...
Third on-off valve, 3d... purge pipe, 4... fifth on-off valve, 4a... outside air communication pipe, 5... controller,
D...Packaging body.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A vacuum container with an opening/closing lid that allows the package to be taken in and out freely, and the intake air from the vacuum container with the lid closed by the operation of the suction pump is transferred to the test gas concentration meter. An intake air test piping system that allows air to be freely discharged from the air to the outside air, and a purge system that releases outside air into the vacuum container with the lid open by operating an air intake pump, and also diverts air from the gas concentration meter to the outside air. A sealed gas leak testing device for a package comprising a piping system. (2) The intake inspection piping system includes an intake piping end opening into the vacuum container, and a first opening/closing valve interposed in sequence;
Consists of an intake pump, a flow rate control valve, a flow meter, a test gas concentration meter that opens to the atmosphere, and a branch discharge pipe that can be opened to the outside air by a fourth opening/closing valve branched from between the intake pump and the flow rate control valve. A device for inspecting a sealed gas leak in a package as claimed in claim 1 of the Utility Model Registration Claim. (3) The purge piping system is equipped with an outside air introduction end, a second opening/closing valve, an intake pump, a flow rate control valve, a flow meter, and a gas concentration meter to be tested that is open to the atmosphere, and the intake air A sealed gas leak testing device for a package according to claim 1, wherein a purge pipe that can be freely opened into the vacuum container is branched from between a pump and a flow control valve by a third on-off valve. . (4) Enclosure of the package according to claim 1 of the utility model registration claim, in which the vacuum container is equipped with an outside air communication pipe that can be freely opened to the outside air by a fifth on-off valve in order to open the opening/closing lid of the vacuum container. Gas leak inspection device. (5) The opening/closing operations of the first to fifth on-off valves are controlled by the electric controller, and whether the detected concentration of the gas concentration meter to be tested reaches a predetermined value or the first on-off valve and the intake When the degree of vacuum of the vacuum gauge branched from the pump reaches a predetermined value, the controller can freely switch from opening the intake inspection piping line to opening the purge piping line by controlling the switch. A sealed gas leakage testing device for a package according to claim 1 of the patent registration claim.