doors extend convexly into the vessel to facilitate the dissipation of explosion shock waves orificed vent pipes penetrate the vessel walls to controllably release explosion products into one or more exhaust manifolds the vessel is surrounded and enclosed by steel skins supported by spaced octagonal steel support ribs fabricated by welding from interlocking elements the hollows formed between the containment vessel and steel skins are filled with granular shock damping silica sand which is introduced through filler openings at the top of the apparatus to lighten the apparatus for transport the shock damping material may be drained through dump valves beneath the apparatus application_number US 201313833060 A description turning to fig1 this isometric perspective view shows the assembled chamber ready for the introduction of an explosive or explosive covered workpiece in use it would be bolted down and supported by a reinforced concrete footing or foundation not shown in a conventional manner as best shown in the remaining figures the chamber assembly 10 comprises a cylindrical inner containment vessel 11 having an inward swinging charging door 21 and a hemispherical end closure 12 the inner vessel 11 is preferably fabricated of sheet steel using conventional welding techniques the vessel 11 is supported and strengthened by multiple equally spaced parallel octagonal stiffener plates or ribs 13 in the illustrated embodiment the inner containment vessel 11 is 34 feet long and is supported by 25 ribs 13 which are equally spaced at 16 inch intervals the assembled inner vessel 11 and surrounding ribs 13 are enclosed by an external enclosure formed of welded sheet steel skin plates 14 each stiffener plate or rib 13 is preferably fabricated from four symmetrical and mutually interlocking quadrants 15 which are sequentially welded together to surround and support the vessel 11.