Testing plastics bottles crates for serviceability - by mechanical or ultrasonic crack test on lifting bars along conveyor

摘要

Method of testing and ensuring the serviceability of plastics containers having handles or lifting bars, for example polyethylene bottle crates or the like, consists of automatically carrying out a mechanical or ultrasonic test on these lifting bars as the crates travel along a production line and, if cracks are detected, ejecting the relevant crate from the line. The ultrasonic method may be by transmission or echo. Pressure is exerted upon the lifting bar (4) of the crate by at least one outwardly pressing sensing head (5) and at least one inwardly pressing sensing head (10), either at different positions and/or at different times. An ultrasonic test head is pressed lightly and elastically against the bar (4), esp. using a water jet to wet the bar and provide acoustic coupling. Useful for crates in bottling factories for beer and similar drinks, where a breakage results in considerable production disturbance, esp. where crates are stacked.