Patent ID: 8672583
Filing Date: 2014-03-18
Classification: E02B,E03F

Abstract:
1. A chamber, comprising: opposing side bases running generally parallel to a chamber length for supporting the chamber; a chamber top; sidewalls running from the opposing side bases to the chamber top, wherein the sidewalls and top form an arch-curve; a plurality of alternating crest corrugations and valley corrugations running transverse to the length of the chamber along the arch-curve of the chamber, wherein the crest corrugations decrease in width with elevation from the opposing side bases, and the valley corrugations increase in width with elevation from the opposing side bases, as width is measured in a direction parallel to the chamber length axis; and a plurality of crest sub-corrugations, each crest sub-corrugation running upwardly from an opposing side base and along a portion of the arch-curve of a crest corrugation, each crest sub-corrugation having a height less than a local height of the crest corrugation with which the crest sub-corrugation is associated, each crest sub-corrugation terminating at an elevation lower than the top of the chamber, wherein the height of each crest sub-corrugation diminishes with increasing elevation.