Collapsible Liquid Tank

Abstract

A collapsible liquid storage tank for use in a freight container for selectively carrying solid freight and bulk liquid freight includes a substantially rigid gantry having a plurality of support posts, a first frame, a second frame suspended from the gantry, a substantially inelastic flexible fabric container having sidewalls connected between the first frame and the second frame, a liquid impermeable elastic bladder disposed within the fabric container and having seals along flat surfaces of the elastic bladder, a centrally positioned outlet, and a hoist coupled between the gantry and the second frame for lifting the second frame towards the first frame.

1 . A liquid impermeable elastic bladder for a collapsible storage tank for carrying bulk liquid freight comprising:
 a first and a second end section, each end section having an end wall, two sidewalls, a top wall, a bottom wall, a sealable edge, a diagonal seal extending along each of the two sidewalls from a first and second corner of the end section to the sealable edge, and, two diagonal seals extending along the top wall from a third and forth corner of the end section to the sealable edge; and   a middle portion having sealable edges coupled to the sealable edges of the first and second end sections.   
     
     
         2 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein the diagonal seals are each welded together. 
     
     
         3 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein the sealable edges of the first and second end sections are each welded to one of the sealable edges of the middle portion. 
     
     
         4 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein the diagonal seals further comprise a one inch overlap. 
     
     
         5 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein the middle portion comprises multiple panels of an elastic material welded together. 
     
     
         6 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein the sealable edges of the first and second end sections each form butt joints with one of the sealable edges of the middle portion. 
     
     
         7 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein the sealable edges of the first and second end sections each form lap joints with one of the sealable edges of the middle portion. 
     
     
         8 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein each end section and the middle portion further include a folded over sealed edge forming a compartment for receiving a rope. 
     
     
         9 . The liquid impermeable elastic bladder for a collapsible storage tank of  claim 1 , wherein the first and second end sections each comprise two end panels coupled to a center panel. 
     
     
         10 . A collapsible liquid storage tank for use in a trailer for selectively carrying solid freight and bulk liquid freight comprising:
 a substantially rigid gantry having a first plurality of support posts;   a first frame;   a second frame suspended from the gantry;   a substantially inelastic flexible fabric container having side walls connected between the first frame and the second frame;   a liquid impermeable elastic bladder having two end sections and a middle portion, each end section having a diagonal seal extending from each corner of an end wall of the end section, the elastic bladder disposed within the fabric container; and   a hoist coupled between the gantry and the second frame for lifting the second frame towards the first frame.   
     
     
         11 . The collapsible liquid storage tank of  claim 10  further comprising an outlet port centrally positioned within a floor of the liquid impermeable elastic bladder. 
     
     
         12 . The collapsible liquid storage tank of  claim 11  wherein the outlet port is removeably attached to discharge piping on a floor of the trailer. 
     
     
         13 . The collapsible liquid storage tank of  claim 12  wherein the inelastic flexible fabric container forms a substantially funnel-shaped bottom configuration when the second frame is lifted into an emptying position. 
     
     
         14 . The collapsible liquid storage tank of  claim 10  wherein the elastic bladder is collapsed when the second frame is lifted towards the first frame into a storage position. 
     
     
         15 . A collapsible liquid storage tank for use in a trailer for carrying bulk liquid freight comprising:
 a first frame coupled to the trailer;   a second frame coupled to the first frame;   a substantially inelastic flexible fabric container having side walls connected between the first frame and the second frame;   a liquid impermeable elastic bladder disposed within the fabric container;   an outlet centrally positioned within a floor of the liquid impermeable elastic bladder; and   a hoist coupled to the first and second frames for lifting the second frame towards the first frame and reducing the spacing between the second frame and the first frame.   
     
     
         16 . The collapsible liquid storage tank of  claim 15  wherein the second frame is suspended approximately six inches from a bottom of the trailer towards the first frame into an emptying position. 
     
     
         17 . The collapsible liquid storage tank of  claim 16  wherein the outlet port is temporarily fixed to the bottom of the trailer in the emptying position. 
     
     
         18 . The collapsible liquid storage tank of  claim 16  wherein the inelastic flexible fabric container forms a substantially funnel-shaped bottom configuration in the emptying position. 
     
     
         19 . The collapsible liquid storage tank of  claim 15  wherein the second frame is suspended proximate the first frame in a storage position. 
     
     
         20 . The collapsible liquid storage tank of  claim 15  in which the liquid impermeable elastic bladder has a substantially smooth inner surface when not expanded.