Measuring and testing – With fluid pressure – Leakage
Patent
1995-11-01
1997-05-27
Williams, Hezron E.
Measuring and testing
With fluid pressure
Leakage
73 407, 73 493, 73 52, G01M 304, G01M 320
Patent
active
056334540
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a pinhole inspecting apparatus for inspecting a pinhole of a flexible closed container.
BACKGROUND ART
In plastic bags in which a tablet or powder drug, for example, is to be contained in closed condition, the presence of any pinhole may lead to a very critical situation. In the case of such plastic bags, therefore, it is necessary to inspect the pinhole strictly.
In a conventional known pinhole inspecting method, a substance which is liable to change in color tone under oxygen or humid conditions, for example, is contained in closed condition in a packaging container, then it is judged on the basis of change in the color tone of the substance whether or not the pinhole or the like is present. Furthermore, a pinhole inspecting method in the case of a rigid container is known in which the container is filled with an inspecting gas under pressure and any leakage gas is inspected by a gas detector to find whether or not a pinhole is present. The gas detector converts any inspecting gas leakage into an electric signal corresponding to amount of the leakage per unit time.
In Japanese Patent Application Nos. 5-344297 and 5-339527, there is disclosed a method and an apparatus, developed by the present inventor, for inspecting a pinhole of a flexible container, such as plastic bag etc., by using a gas detector. In this pinhole inspecting method, any possible leakage of inert gas from an inert gas-filled, closed plastic bag is electrically checked. According to the inspecting method, a threshold value corresponding to a change in electrical conditions caused by environmental change is preliminarily determined for each measurement, and it is judged by checking that the measured value has exceeded the threshold value or otherwise whether or not a gas leakage or a pinhole is present.
In the foregoing pinhole inspecting method, since it is judged whether or not the measured value has exceeded the threshold value, even if a pinhole does exist, it is necessary to wait long until the measured value has reached the threshold value. Therefore, such a problem arises that considerable time is required for quality judgement with respect to containers, and this adversely affects the productivity of the whole manufacturing line.
Furthermore, for example, in the case that the same kind of gas as the gas in the container exists in the ambient atmosphere of the container, namely the object for measurement, the gas will be detected even if a pinhole of the container is not present. Therefore, such a problem arises that it becomes difficult to inspect a pinhole accurately and reliably, thus resulting in drop of reliability of inspection.
An object of the present invention is to provide, with a view to eliminating such conventional problems, a pinhole inspecting apparatus which enables accurate and rapid inspection of pinhole of a closed container so as to satisfy recent requirements of strict quality, performance and rapidity.
DISCLOSURE OF THE INVENTION
In order to accomplish the foregoing object, a pinhole inspecting apparatus according to a first embodiment of the present invention comprises a pallet for dischargeably containing a closed container filled with a gas, the pallet having a suction hole, a gas leakage detecting unit adapted to be connected at an inspecting position to the suction hole for communication with the interior of the pallet, such that when a gas of the same kind as said gas is present in that interior, the gas leakage detecting unit generates an analog signal having a voltage corresponding to amount of the leakage of the gas per unit time, an A/D converter for converting the analog signal into a digital signal, and a first arithmetic unit for finding from the digital signal a slope of a regression line representing the relationship between a voltage corresponding to the magnitude of the signal and time, and calculating the difference between the value of the slope and a maximum slope value which has been preliminarily inputted with respect to a regressio
REFERENCES:
patent: 3591944 (1971-07-01), Wilcox
patent: 3744210 (1973-07-01), O'Lenick et al.
patent: 5029463 (1991-07-01), Schvester et al.
Abe Hiroshi
Ishio Kazuhiko
Murakawa Yoshihiro
Yamamoto Akira
Larkin Daniel S.
Otsuka Pharmaceutical Factory Inc.
Williams Hezron E.
LandOfFree
Pinhole inspecting apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pinhole inspecting apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pinhole inspecting apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2330672