Patent ID: 6330823
Filing Date: 2001-12-18
Classification: G01M

Abstract:
A process for testing the fluid tightness of a plastic container, the plastic container comprising a container body at least partially filled with a fluid and having a flexible base, and walls defining an aperture in the container body, the plastic container further comprising a flexible lid secured to the container body so as to substantially close the aperture therein, the flexible lid being spaced opposite from the flexible base of the container body, the process comprising the steps of:(a) providing a support member having a support surface and at least one aperture extending from an entrance on said support surface through said support member, and providing a sealing member surrounding said entrance;(b) providing pressure varying means for varying the pressure in said aperture between substantially atmospheric pressure and a sub-atmospheric pressure;(c) while the pressure within said aperture is at substantially atmospheric pressure, placing the container on the support member so that a peripheral portion of the flexible base of the container engages the sealing member to form a chamber defined by a predetermined portion of the base of said container and said sealing member, said chamber being in communication with said aperture, but so that the flexible lid is free to move in response to pressure changes within the container;(d) while the pressure within said aperture and said chamber is still at substantially atmospheric pressure, monitoring a characteristic of a sampling area of the flexible lid with an area detector, said sampling area having finite dimensions such that the signal from said area detector represents the behavior of said flexible lid integrated over said sampling area;(e) thereafter causing said pressure varying means to change the pressure in said aperture and said chamber to said sub-atmospheric pressure without changing the pressure applied to the outer surface of the flexible lid, thereby causing a deformation of the flexible base and thus a reduction in the pressure within the plastic container; and(f) repeating said monitoring of said characteristic of said sampling area of the flexible lid at at least one time later than that at which step (e) is carried out.