Abstract: Disclosed are apparatus and methods for testing for leaks in bottles or containers having at least one flexible portion. The apparatus includes one or more test chambers including a means for applying a direct compressive force to the flexible container portion and also a means for measuring the reaction force exerted by the internal pressure in the container to the applied force after at least two predetermined time intervals following application of the direct force while the force is maintained, and means for generating signals indicative of the reactive forces. In its method aspect, the invention provides methods whereby the reaction force is compared with established reference values obtained by applying the same direct force to an identical container having known leak characteristics and establishing by such comparison if the leak rate for the tested container conforms to the established reference values.

Abstract: An air-impingement film dryer having an automatic self-adjusting vent for controlling the intake air flow in response to the increased demand caused by the presence of film in the drying chamber.