Abstract: The integrity of the dividing partitions walls of a multichamber container can be tested for voids after the filling of the containers. This is particularly useful for multichamber tube containers. These containers can have relatively thin tube divider partitioning walls which can have voids in the partitioning, in the attachment of the partitioning to the container walls, or in the case of a tube container the attachment of the dividing partition wall to the shoulder. The container chambers are filled with the substances which also are electrolytes and at the time of filling or just subsequent to filling, a potential difference is applied to each of chambers. Since the substance in each chamber is an electrolyte the potential difference extends throughout each side of the barrier. If there are one or more voids in dividing partition, there will be decrease in the potential difference.

Abstract: A multichamber container must have certain characteristics in order to uniformly dispense the contents of each chamber from the container. The outer wall of the container and the inner divider web walls must have certain characteristics. The inner divider web walls must be highly flexible while the outer container wall must be less flexible. The Deflective Force for the outer wall must be greater than the Deflective Force for the web walls. In addition, to alleviate the problem of suckback of air into the container chambers, the outer wall should exhibit a specific Retention Index. This is a measure of the outer wall to remain deflected after the removal of the deflecting force. The inner divider web wall will have a lower Retention Index than the outer wall. By the proper selection of outer wall and web walls, there can be uniform dispensing from the dispenser. The Stiffness of the outer wall also should be less than the Stiffness for the inner web divider walls.

Abstract: The web for a dual chamber tubular container can be maintained in an alignment across the container by providing one or more longitudinal modified areas on the web so that the web will yield and fold in the areas of the modified material. The modification will be a thinning or weakening of the web to produce yield points, such as fold points. This thinning or weakening can be produced mechanically or chemically. Mechanically, a pinch or other shaped roll can be used to thin or weaken an area. Thermally, heat can be applied. The result is a web that remains in an alignment across a tubular chamber rather than in close contact with the sidewall.