Apparatus and method for testing flexible packages for defects
A method and apparatus for leak detection in flexible packages involves the location of a flexible fluid containing package ( 2 ) in a sealed chamber ( 1 ) and evacuating air from the chamber to a predetermined pressure value. An initial measurement of a reference dimension (h 1 ) of the package is made by a sensor ( 8 ) and after a predetermined period of time a second measurement of the reference dimension (h 1 ) is made by the sensor ( 8 ) to detect any change in that reference dimension as indicative of a leakage of fluid from the package ( 2 ).
1. A method for detection of fluid leaks in flexible packages, said method comprising the steps of:
locating a plurality of flexible fluid containing packages in a sealable common or respective chamber;
bringing into contact with said plurality of packages a flexible membrane to apply a preload of a predetermined value to each of said packages;
reducing the gas pressure within said chamber to a predetermined value;
measuring a reference dimension associated with each said package; and,
after a predetermined period of time, measuring said reference dimension to detect any change in said dimension as indicative of a leakage of fluid for each said package.
2. A method as claimed in claim 1 wherein said preload is determined by the mass of said membrane.
3. A method as claimed in claim 1 wherein said preload is determined by a gas pressure differential between opposite sides of said membrane.
4. A method as claimed in claim 1 wherein said reference dimension is measured against an upper surface of said membrane.
5. A method as claimed in claim 1 wherein said reference dimension is measured from a position within said chamber remote from each said package.
6. A method as claimed in claim 1 wherein said reference dimension is measured relative to a predetermined datum.
7. A method as claimed in claim 6 wherein said predetermined datum is provided by an inner surface of said chamber.
8. A method as claimed in claim 1 wherein said reference dimension is measured by a device selected from an optical, mechanical, electrical, electro-mechanical, sonic, particle emission or particle absorption dimension measuring systems or a combination thereof.
9. A method as claimed in claim 1 wherein said preload of predetermined value is applied to each said package to accelerate fluid leakage from any leakage aperture therein.
10. A method as claimed in claim 1 wherein said preload of predetermined value is applied to each of said packages to smooth out any wrinkles therein.
11. An apparatus for detection of fluid leaks in a plurality of flexible packages, said apparatus comprising:
a sealable chamber having at least one wall defined by a flexible membrane;
a gas evacuation system to reduce gas pressure within said chamber to a predetermined value whereby said flexible membrane is adapted, in use, to contact said packages and apply to each of said packages a preload of predetermined value; and,
a detection device to measure any change in a reference dimension associated with said packages over a predetermined period of time.
12. An apparatus as claimed in claim 11 wherein said apparatus includes a conveyor mechanism to convey said packages into said chamber for leak detection.
13. An apparatus as claimed in claim 11 wherein said apparatus includes a conveyor mechanism to convey said packages from said chamber after leak detection.
14. An apparatus as claimed in claim 11 including a reject mechanism to reject packages identified as having failed at least one predetermined leak test criterion.
15. An apparatus as claimed in claim 11 wherein said apparatus is adapted to detect leakages in single packages.
16. An apparatus as claimed in claim 11 wherein said apparatus is adapted for leak detection in any one of a plurality of packages in a batch process.
17. An apparatus as claimed in claim 11 wherein said apparatus is adapted for leak detection in any one of a plurality of packages in a continuous system.
18. An apparatus as claimed in claim 11 wherein said detection device is selected from any suitable position detecting system including optical, mechanical, electrical, electro-mechanical, sonic, particle emission or particle absorption position detectors or any combination thereof.
19. An apparatus as claimed in claim 11 wherein said detection device is located internally of said chamber.
20. An apparatus as claimed in claim 11 wherein said detection device is located externally of said chamber.
21. An apparatus as claimed in claim 11 wherein said membrane is adapted to apply a preload of predetermined value to each of said packages to accelerate fluid leakage from any leakage aperture in a package.