Patent ID: 6347886
Filing Date: 2002-02-19
Classification: B29C,B29L,B65D

Abstract:
In a thermoplastic film tank liner which when disposed within a generally cylindrical tank and containing a liquid has a generally cylindrical configuration, said tank liner having an opened top, side walls and a closed base, the improvement wherein the closed base comprises:(1) a first flap and a second flap extending from lower portions of a first side wall and having, respectively, a first angular edge and second angular edge; (2) a third flap and a fourth flap extending from lower portions of an opposite side wall and having, respectively, a third angular edge and a fourth angular edge; (3) a first intermediate flap and a second intermediate flap extending, respectively, from the lower portions of the first side wall and the opposite side wall and positioned, respectively, between the first flap and second flap and the third flap and fourth flap, wherein each intermediate flap has transverse portions joined together and, respectively, first left angular edge and first right angular edge and opposite left angular edge and opposite right angular edge; and (4) a seam between: (a) the first angular edge and the first left angular edge; (b) the second angular edge and the first right angular edge; (c) the third angular edge and the opposite left angular edge; and (d) the fourth angular edge and the opposite right angular edge; wherein all of said angular edges have angles such that the base presents a substantially flat surface of approximately a circular configuration when the liner is disposed in said tank and contains a liquid, wherein the first side wall and the opposite side wall have a seam extending from an outermost portion of the seam between the first angular edge and the third angular edge to at least near the opened top of the liner, and wherein the first side wall and the opposite side wall have a seam extending from an outermost portion of the seam between the second angular edge and the fourth angular edge to at least near the opened top of the liner.