DESIGN AND METHOD OF FABRICATION OF COLLAPSIBLE STORAGE TANK
In one embodiment, a collapsible, flexible storage tank is provided that is capable of holding a liquid material. The tank includes a sheet of flexible, moisture impervious side wall material; at least one opening for receiving a fitting to fill and drain the tank; joining seams wherein edges of the sheet are joined, the seams extending about the tank in a spiral orientation; and closing seams wherein the side ends of the pillow tank are sealed. In another aspect, a collapsible, flexible storage tank is capable of holding a liquid. The tank includes a sheet of flexible side wall material; at least one opening for receiving a fitting to fill and drain the tank; and butt seams wherein edges of the flexible sheet are joined together in the same plane in a butt joint configuration using an overlapping piece of flexible, moisture impervious sealed material over the top thereof.
1 . A collapsible, flexible storage tank capable of holding a liquid material, including: a sheet of flexible, moisture impervious side wall material; at least one opening for receiving a fitting to fill and drain the tank; joining seams wherein edges of the sheet of material are joined, the seams extending about the tank in a spiral orientation; and closing seams wherein the side ends of the pillow tank are sealed.
2 . The collapsible, flexible storage tank as set forth in claim 1 , wherein only two or less joining seams encounter a closing seam at each end of the tank.
3 . The collapsible, flexible storage tank as set forth in claim 1 , wherein at least some of the seams are characterized by a butt joint configuration and a length of flexible, moisture impervious material overlapping the butt joint and sealed to the sheet of material.
4 . The collapsible, flexible storage tank as set forth in claim 3 , wherein the length of flexible, moisture impervious material is attached along an outside surface of the storage tank.
5 . The collapsible, flexible storage tank as set forth in claim 4 , further including a sealing tape along and covering the butt joint on an inside surface of the tank.
6 . The collapsible, flexible storage tank as set forth in claim 4 , further including a second length of flexible, moisture impervious material located along and sealed to an inner surface of the storage tank and covering the butt joint.
7 . The collapsible, flexible storage tank as set forth in claim 4 , including a filler material located between edges of the sheet material along and within the butt joint.
8 . A collapsible, flexible storage tank capable of holding a liquid material, including: a sheet of flexible, moisture impervious side wall material; at least one opening for receiving a fitting to fill and drain the tank; and butt seams wherein edges of the flexible sheet of material are joined together in the same plane in a butt joint configuration using an overlapping piece of the flexible, moisture impervious sealed material over the top thereof.
9 . The collapsible, flexible storage tank as set forth in claim 8 , including a piece of sealing tape on the internal side of the butt joint.
10 . The collapsible, flexible storage tank as set forth in claim 8 , further including a second piece of flexible, moisture impervious sealed material located along an inner side of the seam.
11 . The collapsible, flexible storage tank as set forth in claim 8 , further including a flexible, filler material located between edges of the flexible sheet of material in the butt seams.
12 . The collapsible, flexible storage tank as set forth in claim 8 , wherein at least one butt seam extends about the tank in a spiral orientation.
13 . The collapsible, flexible storage tank as set forth in claim 13 , wherein only two or less spiral seams encounter a closing seam at each end of the tank.
14 . A method of fabricating a collapsible, flexible storage tank capable of holding a liquid material, including the steps of: providing an elongated sheet of flexible, moisture impervious side wall material; winding the sheet of material in a spiral orientation to form a side wall of the storage tank; joining edges of the sheet material to form a spiral seam about the tank; cutting ends of the sheet of material to form straight side ends; and making closing seams wherein side ends of the pillow tank are sealed.
15 . The method of fabricating a collapsible, flexible storage tank as set forth in claim 14 , wherein only two or less spiral seams encounter a closing seam.
16 . The method of fabricating a collapsible, flexible storage tank as set forth in claim 14 , further including the step of joining the spiral seam in a butt joint configuration with edges of the sheet of material facing one another.
17 . The method of fabricating a collapsible, flexible storage tank as set forth in claim 16 , further including the steps of: placing a length of the flexible, moisture impervious material over the butt joint; and sealing the length of material to surfaces of the side wall material along the butt joint.
18 . The method of fabricating a collapsible, flexible storage tank as set forth in claim 17 , further including the steps of: sealing a second length of material to the surface of the side wall material on the opposite side of the tank from the first length; and sandwiching the butt joint therebetween.
19 . The method of fabricating a collapsible, flexible storage tank as set forth in claim 17 , further including the step of placing a filler material between edges of the butt joint.
20 . The method of fabricating a collapsible, flexible storage tank as set forth in claim 17 , further including the step of placing a sealing tape along the butt joint on the opposite side of the joint from the length of the sheet of material.