Collapsible storage tank

A flexible and collapsible storage tank for holding large volumes of material comprising in combination:

• a substantially homogeneous rectangular tank body comprised of integrally vulcanized inner and outer envelope structures of rubberized square-woven fabric, the inner envelope structure formed by a plurality of long lengths of fabric having overlapping adjacent edges and oriented longitudinally while the outer envelope structure is formed by a plurality of edge plies of fabric folded about the peripheral edges of inner envelope structure and a plurality of lengths of fabric having overlapping adjacent edges and oriented orthogonally on either side of the inner envelope structure;
• a vent valve mounted in the top of the tank body to communicate air into and out of the interior thereof when filling and emptying the tank body;
• and
• closure means mounted at one end and across a corner exposure of the tank body to seal the corner exposure and provide a connection for communication into the tank body.