SPIRALLY WOUND TUBE WITH VOIDS AND METHOD FOR MANUFACTURING THE SAME

摘要

A spirally wound tube (10) having an intermediate zone (30) defining one or more voids and a method of making such, a tube. The tube is made by spirally winding a plurality of plies and mini-plies together forming an inner zone (20) , intermediate zone (30) , and an outer zone (40) . Each zone has one or more layers (120,130,140) of plies or mini-plies. More specifically, each intermediate layer includes a number of mini-plies spirally wound with gaps between adjacent mini-plies. Furthermore, the intermediate layers are radially aligned with each other such that the gaps of each layer form voids. Each void has a radial height substantially equal to the radial height of the intermediate layers combined or the intermediate zone.