Multilayer tube formed of profiled strip

摘要

A tube made of profiled strip has an inner edge, an outer edge parallel to the inner edge and projecting away from the inner edge, a double-thickness outwardly directed inner lip forming between the edges an outwardly open inner slot, and a double-thickness inwardly directed outer lip forming between the inner slot and the outer edge an inwardly open outer slot. The strip is formed into turns centered on an axis with the inner slot of each turn axially slidably receiving the outer lip of the adjacent turn on an inner side and the outer slot of each turn axially slidably receiving the inner lip of the adjacent turn on an outer side.