Abstract: This invention relates to apparatus and methods for in-line testing for leaks in flexible containers traveling along a production line at high speeds. The apparatus inspects semi-rigid plastic containers at a high capacity by using multiple sensors at fixed displacements along a compression section while analyzing the response of the sensors such that internal pressure decays of leaky containers are readily discernible without interrupting the flow of the production line.

Abstract: A pressure-sensitive switch comprises a base member having a mounting surface formed of electrically-insulating material; two electrodes mounted on the base member and each having an electrically-conductive contact surface, and a flexible diaphragm having its periphery secured in a fluid-tight manner to the mounting surface with its electrically-conductive central portion overlying the contact surfaces of the electrodes. The diaphragm, which is formed with plural corrugations, is exposed to the external pressure. When the switch is exposed to atmospheric pressure, the central portion of the diaphragm does not touch the contact surfaces of said electrodes, but when the switch is exposed to a super-atmospheric pressure, this central portion is forced into contact with both contact surfaces, thus electrically connecting the two electrodes. This pressure-sensitive switch is especially useful for use with hydrophones, as in seismic streamer cables.

Abstract: A sensor structure for use with container inspection systems utilizes a continuous-wave (CW) microwave radar to measure the curvature or the vibration characteristics of a container wall through a thick corrugated cardboard case top or on a single item container processing line. A radar antenna directs RF energy toward cans moving along a conveyor. The antenna emits a beam which, over time, illuminates a narrow region along a line from one outer edge of the can to the opposing outer edge, as the can passes the antenna. During this time, a continuous measurement of the relative change in distance from the antenna to the top of the can is generated and sampled for acquisition by a computer, and an estimate of the profile is made from changes in the distance measurement. The profile is used as a measure of the internal pressure of the can or as an indication of the presence of manufacturing defects.

Abstract: Leak detector for use in detecting defective flange-shaped seals between lid and body portions of a package. A pressure chamber is provided for isolating the external edge of the seal and applying test pressure thereto. Containment of the pressure chamber includes sealing pressure applied mechanically to the flange-shaped package seal during testing, but this sealing pressure does not affect seal testing because it is appropriately limited by a self-compensating biasing of the mechanical seal. Also disclosed is a leak testing method that involves directing gas over a flexible lid at sufficiently high velocity to lift the lid at gross defects in a seal and inject gas through the gross defects. Also disclosed is a package design that employs channels to direct gas into a seal region.

Abstract: Leak detector for use in detecting defective flange-shaped seals between lid and body portions of a package. A pressure chamber is provided for isolating the external edge of the seal and applying test pressure thereto. Containment of the pressure chamber includes sealing pressure applied mechanically to the flange-shaped package seal during testing, but this sealing pressure does not affect seal testing because it is appropriately limited by a self-compensating biasing of the mechanical seal.