Multi-layer container

Claim 1

A multi-layer pressure container comprising in combination: a core in the form of a body of rotation about a longitudinal axis; a plurality of sheet metal plates having longitudinal edges, one of which plates is wrapped directly around the core with the edges of the plate in opposed relation to form a longitudinal seam, which seam is substantially opened by the lack of continuous welding material along the length of the longitudinal seam; the other plates being wrapped about the first plate in superimposed relation with respect to one another with each plate forming a seam between the opposed longitudinal edges thereof; the seams being displaced arcuately with respect to one another whereby the seams are not linearly aligned on the same radius and whereby there is a distribution of seams substantially throughout 360° of rotation; and welds distributed in the longitudinal seams of a plurality of the other plates with the volume of welded material from one plate of said plurality of said other plates to another plate of said plurality of said other plates increasing in the radially outward direction, with the seam of the outermost plate of said container being completely welded along the length thereof and being completely filled with welded material.