JP4070738B2 - Inspection method for liquid containers - Google Patents

Description

The present invention relates to the inspection how the liquid container. The liquid container referred to here is a flat bag shape made by adhering a flexible sheet, and has a part of which has a vent hole. Such a liquid container is used for medical purposes, for example, as a container for temporarily storing bodily fluids discharged from the human body, particularly as a waste liquid bag for collecting urine of a patient who cannot move after surgery.

  The waste liquid bag is made of a flexible synthetic resin sheet, and is bonded to form a bag-like structure as shown in FIG. In FIG. 1, a dotted line 1 is an adhesive portion formed by adhering two sheets to form a bag, 2 is an inlet provided at the top of the bag, and 3 is provided at the bottom of the bag. In addition, soft tubes 4 and 5 are attached to the inlet 2 and the outlet 3, respectively.

  A vent hole 6 is provided above the bag inlet 2. The vent 6 is for facilitating the flow of liquid such as urine into the bag. For example, as shown in FIG. 2, the air holes 6 are formed by forming four small holes 7 having a diameter of, for example, about 3 mm in a sheet L constituting the bag, placing a nonwoven fabric 8 on the holes 7, and forming a peripheral edge 9 of the nonwoven fabric 8. Is adhered to the sheet L. The fine holes present in the nonwoven fabric 8 serve to pass gas but not liquid, so that the air holes 6 allow air to pass but not liquid.

  The waste liquid bag is formed by laminating two sheets and bonding the entire periphery thereof, but when the liquid is put therein, the liquid bag must not leak from the bonded portion. The bonded portion 1 made by bonding is usually pressed firmly against the sheet and has a considerable width, so that it does not easily peel off or cause fluid leakage. However, if the sheet happens to be a fold or a foreign object is interposed between the sheets at the contact portion, an adhesion failure will rarely occur. Therefore, the waste bag rarely causes liquid leakage. Therefore, all the waste liquid bags are inspected for liquid leakage from the bonded portion.

  In general, the inspection of whether or not a bag leaks liquid is performed by blowing air into the interior instead of putting liquid inside. However, since the waste bag is provided with the vent hole 6 as described above, it cannot be inspected by simply blowing pressurized air into it. Therefore, until now, there is an inspection method in which a waste liquid bag is submerged in water, pressurized air is sent to the waste liquid bag in water, and whether there is air leakage from the adhesive portion 1 other than the vent hole 6 is visually observed. Adopted.

  However, the above-described inspection method has a problem in that there is an error in the results depending on the practitioner, and it takes time to carry out the operation and requires cumbersome work. This is because relying solely on the operator's observation for the presence or absence of air leakage has a large error due to oversight and subjectivity of the observer, and in order to discharge pressurized air from a bag submerged in water, This is because a large amount of air needs to be sent to the tank, and therefore inspection takes time. Furthermore, after the inspection is finished, it is necessary to wipe off the water adhering to the bag and dry the bag, which is cumbersome and takes time. Therefore, it has been necessary to devise a method that can inspect whether or not there is liquid leakage from the bonded portion in a shorter time.

On the other hand, Japanese Patent Laid-Open No. 6-288856 describes a method for measuring the presence or absence of air leakage in a hollow molded product. In this method, in addition to a hollow molded product that requires inspection, a hollow molded product that is the same size and the same size as this hollow molded product and has no air leakage is prepared, and both molded products are pressed under the same conditions. Alternatively, after a certain time has elapsed after the pressure is reduced, the pressure difference indicated by both hollow molded articles is measured to determine the degree of air leakage.
JP-A-6-288856

  According to the description of the publication, the hollow molded article targeted by this publication is assumed to include all those having hollow parts such as pipes and tanks, and the material includes all materials such as plastic, glass, metal, It is explained. However, considering that this publication includes as a means for inspecting the pressure reduction of the hollow molded article, it is considered that the hollow molded article is not intended for a flexible bag. This is because it is unlikely that an air leak can be measured by decompression in a flat and flexible bag.

  Therefore, Japanese Patent Application Laid-Open No. 6-288856 is intended only for a molded product having a constant internal volume, such as a bag, and only teaches a method for measuring air leakage with respect to such a molded product. It does not teach how to measure air leaks in flexible and flat bags such as bags. In particular, since the waste liquid bag has a vent hole, the method of the above publication cannot be applied immediately.

  The present invention relates to a liquid container such as a waste liquid bag, that is, a flat bag-like product made by adhering a flexible sheet and having a vent hole in a part thereof from an adhesive part. It is an object of the present invention to provide a method and an apparatus capable of easily and reliably inspecting whether there is a liquid leak in a short time.

  The present invention provides a standard container that is confirmed to be the same type of specimen as the specimen and free from air leakage, while temporarily closing the vent hole of the liquid container to be examined. Focusing on the fact that it is flexible and can be inflated in any way, prepare an expansion restriction frame, put the sample and standard container in the same type of expansion restriction frame, and press-fit air into each container under the same conditions Thus, it is essential to leave both containers in a state where the expansion is limited by the above-mentioned frame for a while, and then measure the air pressure in each container and determine the presence or absence of liquid leakage from the difference in air pressure. .

  In this invention, an impermeable film is stuck to temporarily close the vent hole. A pressure sensitive adhesive is used as an adhesive for pasting. The pressure-sensitive adhesive is generally applied in advance to a substrate and used as a layer formed on the substrate, and is usually used as an adhesive for an adhesive tape. A pressure-sensitive pressure-sensitive adhesive easily adheres to another material when the pressure-sensitive adhesive is pressed against the other material, but its adhesive strength is much weaker than that to the substrate. Therefore, if an adhesive made by applying a pressure-sensitive adhesive to an impermeable film as a base material is adhered to the vent hole, the vent hole can be blocked, and if the impermeable film is peeled off, The pores can be reinstated.

  In the present invention, a container of the same kind as the liquid container to be inspected, which is confirmed to have no air leakage at all, is prepared and used as a standard container. In this invention, a standard container and the above-mentioned specimen are arranged, air is injected into these two containers under the same conditions, the air pressure in each container is measured after a certain period of time, and air leakage is determined from the difference in air pressure. To do.

  In the present invention, when air is pressed into two containers, a frame that restricts the expansion of the containers is used. The expansion restriction frame serves to suppress the expansion of the container within a range of 10 to 90% of the maximum expansion volume.

  This invention consists of a flat bag made by adhering a flexible sheet, and inspects the presence or absence of liquid leakage from the adhering portion of a liquid container having a vent hole in the upper part. In addition to the liquid container, prepare a standard container that is the same type as the container and does not leak air, and apply an impermeable film pre-applied with a pressure-sensitive adhesive to the vent of the liquid container. The sample with the closed pores is used as a specimen, and the specimen and the standard container are placed in an expansion restriction frame of the same shape and size, respectively. Air is injected into both containers under the same conditions, and both containers are inflated by the above frame. A method for inspecting a liquid container, characterized in that the liquid container is maintained in a suppressed state, and thereafter the air pressure in each container is measured, and it is determined that there is no liquid leakage when the air pressure difference is within an allowable range. Is to provide.

  The present invention also relates to an apparatus for inspecting the presence or absence of fluid leakage from an adhesive portion in a flat bag-like liquid container made by adhering a flexible sheet, the liquid container and the container And a pressurized air supply device for supplying pressurized air to a standard container that has been confirmed to have no fluid leakage, and an expansion for containing the container and limiting the expansion of the container The present invention provides a liquid container inspection device comprising a restriction frame and a pressure gauge for measuring the air pressure in the container.

  According to this invention, an impermeable film pre-applied with a pressure-sensitive adhesive is applied to the vent of a liquid container having a vent, and the sample with the vent closed is used as a sample. The air pressure in the container can be measured by press-fitting, and thereby air leakage can be measured. Also, since a pressure-sensitive adhesive is used to attach the impervious film, if the impervious film is peeled off after the measurement, the pressure-sensitive adhesive will not leave any vents on the side. Can be used for inspection without damage.

  Further, according to the present invention, in addition to the liquid container to be inspected for liquid leakage, a standard container that is the same type of container and has been confirmed to have no air leakage is used. By comparing the above, it is possible to easily and reliably know the degree of liquid leakage of the entire liquid container, including not only air leakage from the bonded portion but also air leakage due to pinholes in the sheet.

  Furthermore, according to the present invention, the container expansion restriction frame is used, and the container is placed therein and the air is press-fitted into the container. Therefore, the air pressure in the container can be increased without expanding the container to the maximum expandable volume. Therefore, air leakage can be measured with a reduced amount of air injection. Therefore, the time required for the inspection can be shortened and the inspection efficiency can be increased. The present invention provides such benefits.

  In this invention, a flexible sheet is used as a material for forming the liquid container. However, it is preferable to use a flexible sheet made of resin. As the resin, it is preferable to use a soft vinyl chloride resin or a low crystalline polyolefin resin based on propylene, which is generally called a CAP resin.

  In order to bond the two sheets, an adhesive having a strong adhesive force may be prepared for the sheets and bonded with the adhesive. However, it is preferable that the sheet itself is melted and bonded by heat without using an adhesive. In particular, when the sheet is made of a vinyl chloride resin, it is preferable to apply a high frequency voltage to the sheet to melt and bond the resin. When the sheet is made of polyolefin, it is preferable to apply a heated blade to melt the sheet and bond it.

  A flat bag-like container obtained by adhering a flexible sheet in this way is generally strong and does not easily peel off from the bonded portion. In addition, this container usually does not cause liquid leakage from the bonded portion. However, since the adhesion failure occurs due to the unexpected cause as described above, and liquid leakage may occur in rare cases, 100% inspection is performed.

  In the present invention, an impermeable film is used to close the vent hole. As an impermeable film, most films other than a nonwoven fabric and a perforated film can be used. For example, an ordinary synthetic resin film, specifically, a soft vinyl chloride resin film, a polyolefin film, a polyester resin film, or the like can be used. In addition, cellophane paper can also be used. Therefore, in the liquid container used in the present invention, the cellophane adhesive tape can be attached to the vent hole to close it. The liquid container with the vent hole closed in this way is used as a specimen.

  Among liquid containers, the waste liquid bag used for medical purposes is made by stacking two sheets of 200-400mm on each side and adhering the entire periphery, so the inner volume is approximately 2,000-20,000cc belongs to.

  In this invention, a standard container is used. This standard container is required to be the same type as the liquid container to be measured, and to be confirmed as having no air leakage. Therefore, as the standard container, a liquid container to be inspected, which is confirmed to be free from air leakage by closing its vent hole, can be used. In addition, a liquid container having no air holes made by bonding two sheets of the same size and the same size as the sheets constituting the liquid container, which has been confirmed to have no air leakage, is used as a standard container. be able to.

  The expansion restriction frame used in the present invention is composed of a lower plate for placing a liquid container to be inspected and an upper plate for contacting the container and suppressing its expansion when the container is inflated by air. It is preferable that the upper plate and the lower plate face each other in parallel and the distance between them can be changed.

  The lower plate and the upper plate must be made of a strong and rigid material. The shape may be a flat plate without holes, or small holes may be formed in some places. In an extreme case, it may be a wire net with a small mesh. In addition, the upper plate and the lower plate may constitute a curved surface along the shape when the liquid container swells.

  In order to change the distance between the upper plate and the lower plate, it is preferable to connect the four corners of the upper plate and the lower plate with bolts and nuts. The space between the container is when the stencil sheet with the inlet of the liquid container attached is placed on top of the other stencil sheet on the lower plate, and the container is swelled to the maximum by injecting air into the container. It is necessary to make it 10 to 90% of the height. In this, it is preferable to set it as 40 to 70%.

  In this invention, the specimen and the standard container are placed in a frame that restricts expansion to the same ratio, and air is injected into both containers under the same conditions. If the press-fitting air pressure is low, it takes time to inflate the container. On the other hand, if it is high, press-fitting can be done in a short time, but the container may be damaged. A suitable pressure is in the range of 5-100 Kpa. Of these, the range of 15 to 35 Kpa is preferred. When air is injected with such a pressure, a container about the size of a waste liquid bag expands to the maximum volume limited by the frame in a few seconds to a few seconds.

  After the container reaches the maximum volume, the supply of pressurized air is stopped, the air inlet to each container is closed, and each container is isolated and maintains the internal pressure for several seconds to several seconds. put. If there is a hole in the specimen that allows liquid to leak, the specimen will reduce pressure during this time.

  Therefore, the air pressure that each container holds after being left is measured. If the difference in air pressure is within the allowable range for each container, the container is determined not to leak liquid. If the pressure difference is 50 pa or less in the waste liquid bag, it is determined that liquid leakage does not occur.

  An example of the implementation of the method of the present invention will be described with reference to the drawings as follows. FIG. 3 is a model diagram of an expansion restriction frame that can be used in the present invention, and FIG. 4 is an explanatory diagram of an inspection method according to the present invention.

Example 1
A soft vinyl chloride sheet having a thickness of 0.3 mm was cut into a right-angled quadrilateral having a length of 260 mm and a width of 320 mm. As shown in FIG. 1, the cut sheet was provided with an injection port 2 at the top, a discharge port 3 at the bottom, and a vent 6 above the injection port to form a sheet L. Another similar sheet that was cut out was designated as sheet M without any inlet, outlet, or vent. The sheet L was overlaid on the sheet M, the periphery of the sheet was heated and melted, and the adhesive portion 1 having a width of about 3 mm was formed over the entire circumference, thereby producing a waste liquid bag R having a structure as shown in FIG.

  In this case, as shown in FIG. 2, the vent hole 6 has four holes having a diameter of 3 mm in the sheet L, and a non-woven fabric having a side of 20 mm on one side covering these holes is placed on the non-woven fabric. The periphery was formed by adhering to the sheet L. This sheet had a maximum volume of 3600 cc when pressurized air of 25 Kpa was pressed into it.

  Apart from the above-mentioned waste liquid bag, a standard container Y was prepared which was a waste liquid bag of the same shape and the same size and was not provided with the vent hole 6 and was confirmed to have no air leakage.

  An expansion restriction frame was prepared. As shown in FIG. 3, as the expansion restriction frame, two iron plates having a length of 500 mm, a width of 500 mm, and a thickness of 10 mm, ie, an upper plate A and a lower plate B, are placed in parallel at intervals, and bolts are placed at the four corners of each iron plate. It was connected through C and fixed with a nut D so that the distance between the upper plate A and the lower plate B could be adjusted. Two such expansion restriction frames are arranged, and P and Q are respectively designated.

  Regarding the waste liquid bag R whose liquid leakage should be measured, first, the vent hole 6 attached thereto was closed. For this purpose, an adhesive film made by applying a pressure-sensitive adhesive to one surface of a soft vinyl chloride film was attached to the entire surface of the vent hole. The waste liquid bag that closed the vent hole 6 in this manner was used as the specimen X. The specimen X was placed in an expansion restriction frame P in which the distance between the upper plate and the lower plate was adjusted to 50 mm. The interval of 50 mm is a size that suppresses the specimen X to an expansion ratio of approximately 50% of the maximum expansion volume.

  In addition, the standard container Y described above was placed in an expansion restriction frame Q in which the distance between the upper plate and the lower plate was adjusted to 50 mm as in the expansion restriction frame P. Next, in both the specimen X and the standard container Y, the exhaust port is closed, the respective inlets are connected to the air pipe Z from the air pressurizer, and 25 Kpa of pressurized air is injected into each container. The injection was stopped when the internal pressure reached 25 Kpa. The press-fitting took 9 seconds.

  After each container showed an internal pressure of 25 Kpa, the supply of pressurized air was immediately stopped, the air supply port to each container was closed, and each container was left in an isolated state for 12 seconds. After that, the internal pressure of each container was measured, and the difference between the internal pressures was calculated. If the difference was 50 pa or less, no liquid leakage occurred.

  Thereafter, the air in the container was discharged, the specimen and the standard container were taken out of the expansion restriction frame, the impermeable film attached to close the vent hole was peeled off, and the specimen was flattened to obtain a product.

  In this way, even if it takes time and labor to put a specimen and a standard container into and out of the expansion restriction frame, and to apply and peel an impermeable film, it is necessary to inspect the leakage of the liquid container. The effort was minimal, and the time was compensated by shortening the air pressure entry time. As a whole, the inspection could be completed in about 21 seconds.

Comparative Example 1
Pressurize the air into the above-mentioned liquid container to inflate the container, submerge the inflated container in water and measure the air leakage from the adhesive part, take out the container from the water and scatter the adhering water with an air gun, and roughly It took about 25 seconds to remove. However, it was necessary to further dry the container before it was made into a product, and it took about 30 minutes to dry.

  In addition, when observing air leakage after being submerged in water, the entire required time hardly changed even when the vent hole of the liquid container was closed with an adhesive tape.

Comparative Example 2
Although this comparative example is not a known method, it was carried out just in case. This comparative example was different from the method of Example 1 only in that no expansion restriction frame was used. Then, it was necessary to press-fit the pressurized air for about 25 seconds until the air pressure in the specimen and the standard container reached 25 Kpa. The swelling width of the liquid container at this time was 135 mm. Therefore, in Comparative Example 2, the air press-in time is 16 seconds longer than in Example 1, and the same extra time is required for air discharge. Took more time.

The top view of the liquid container used by this invention. FIG. 2 is an enlarged view of a vent hole of the liquid container shown in FIG. 1. The model figure which shows the state which put the liquid container in the expansion | extension restriction | limiting frame used by this invention. Explanatory drawing of the apparatus used with the inspection method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Adhesive part 2 Inlet 3 Outlet 4 5 Tube 6 Ventilation hole 7 Hole 8 Nonwoven fabric 9 Non-woven fabric 8 peripheral edge A Upper plate B Lower plate C Bolt D Nut L, M Sheet P, Q Expansion restriction frame R Waste liquid bag X Sample Y Standard container Z Air pipe

Claims (1)

  In addition to liquid containers that should be inspected for liquid containers that have a flat bag shape made by adhering a flexible sheet and that have vents in the upper part, for inspection of liquid leakage from the bonded parts In addition, a standard container of the same type as that container that does not leak air is prepared, and an air-permeable film pre-applied with a pressure-sensitive adhesive is pasted on the air hole of the liquid container to close the air hole. The sample and the standard container are placed in an expansion restriction frame that restricts the same bulge, and air is pressed into both containers under the same conditions, and both containers are kept in a state where expansion is suppressed by the frame. A method for inspecting a liquid container, comprising: maintaining and then measuring the air pressure in each container and determining that there is no liquid leakage when the air pressure difference is within an allowable range.

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