Measuring and testing – With fluid pressure – Leakage
Patent
1998-01-06
1999-06-29
Dougherty, Elizabeth L.
Measuring and testing
With fluid pressure
Leakage
73 52, 73 414, G01M 304
Patent
active
059182709
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a method and a device for testing for tightness deformable containers which regain their original form through their inherent or an external restoring force, particularly plastic containers, whereby a negative pressure is generated in the container and a change in the negative pressure is determined.
2. Scope of the Prior Art
In the case of so-called returnable plastic containers, particularly beverage bottles, and unlike returnable glass bottles, internal pressure tests are necessary prior to a refilling, due to the thinness of their walls and the risk of embrittlement of the material due to ageing. The purpose of the internal pressure test is to detect holes and embrittlement cracks in the container wall.
Hitherto, this has been very elaborately effected by means of a rotary machine with a star wheel, each bottle being transported in a star wheel compartment where it is pressurized with a defined pressure, and pressure changes being measured and evaluated after a definite period of time or a definite distance by means of a differential pressure measuring device. This measuring device must be set on the bottle opening in an extremely precise and impervious manner. This is relatively easily achievable due to the defined guidance of the bottles by means of the star wheel.
A method of the type initially referred to is known from U.S. Pat. No. 3,762,213. In this case, the negative pressure in the container is generated in that a cylinder with a displaceable piston is set on the container opening and the piston is then retracted. Due to the negative pressure, the container is then suspended from the cylinder, and the period of time for which the container is suspended from the cylinder is used as a measure of the tightness of the container.
Known from U.S. Pat. No. 4 862 732 and DE-A-41 21 867 is a method for testing the tightness of containers closed with caps, in which an overpressure is generated in the container by deformation of the container. The bulging of the container cap is used as a measure of the generated overpressure.
SUMMARY OF THE INVENTION
The object on which the invention is based is the development of the internal pressure test of the type initially referred to in such a way that the containers can be subjected to the internal pressure test at any temporal or spatial intervals.
This object is achieved, according to the invention, in that the internal pressure in the container differing from the ambient pressure is generated by deformation of the container.
For the purpose of producing the negative pressure, the container is first deformed and the container opening is then closed, whereupon the deformation force is removed from the container so that the latter resumes its normal shape, due to its elasticity of form, resulting in the generation of the negative pressure in the container. In this working with negative pressure, it is particularly advantageous that the container opening can be closed simply by setting an elastic strip on the container opening. Due to the negative pressure produced following the removal of the deformation force, the elastic strip is sucked on to the container opening, and thereby closes the latter tightly. In so doing, the elastic strip forms a depression within the container opening. The level of the negative pressure can be easily derived from the magnitude of the depression.
In the case of beverage filling installations, there exists the principle of delivery under accumulation pressure and, in contrast to this, the principle of pressureless delivery. Delivery under accumulation pressure means that the containers accumulate and press against one another on the transporters between the individual stations, e.g. washing station, monitoring station and filling station. This is achieved by the fact that the containers are delivered to a station or to a preceding star wheel more rapidly than they can be handled by the station or indexed by the star wheel. The containers thus accumulate
REFERENCES:
patent: 3824840 (1974-07-01), Amberg
patent: 3847014 (1974-11-01), Mistarz
patent: 3879987 (1975-04-01), Yasuhiro et al.
patent: 3930401 (1976-01-01), Filler
patent: 3998091 (1976-12-01), Paquette et al.
patent: 4081991 (1978-04-01), Powers, Jr.
patent: 4188819 (1980-02-01), Egee et al.
patent: 4747298 (1988-05-01), McDaniel
patent: 4747299 (1988-05-01), Fox et al.
patent: 4756184 (1988-07-01), Reishus et al.
patent: 4788850 (1988-12-01), Buschor et al.
patent: 4862732 (1989-09-01), Raymond
patent: 4864848 (1989-09-01), Irvine
patent: 4930345 (1990-06-01), Bausch
patent: 5033287 (1991-07-01), Watanabe et al.
patent: 5497654 (1996-03-01), Lehmann
patent: 5507177 (1996-04-01), Focke
patent: 5571949 (1996-11-01), MacLaughlin
patent: 5767392 (1998-06-01), Belcher et al.
Dougherty Elizabeth L.
Heuft Systemtechnik GmbH
LandOfFree
Process and device for testing deformable containers for tightne does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and device for testing deformable containers for tightne, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and device for testing deformable containers for tightne will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1387432