Flexible tanks for transporting bulk products

Abstract

The specification discloses a filling/discharging structure ( 10 ) for a flexitank. The structure ( 10 ) comprises a main part ( 12 ) and a nut ( 32 ). The main part comprises an externally threaded spigot ( 20 ) encircled by a disc-like flange ( 22 ). The flange and nut have concentric patterns of ribs and grooves. The grooves are designated 38, 40, 42, 44 and the ribs are on the inner face of the flange ( 22 ) and not visible in the drawing. When the nut ( 32 ) is screwed onto the spigot 20, the ribs enter the grooves ( 38, 40, 42, 44 ) and the wall of the flexitank is gripped between the ribs and grooves. The configuration is such that the radially innermost rib and groove pair grip the tank wall most tightly and the grip on the tank wall by the rib and groove pairs outwards of the innermost rib and groove pair decreases with distance from the innermost rib and groove pair.

1 . A filling/discharging structure for a flexible tank, the structure comprising an externally threaded spigot encircled by a disc-like flange, the flange having concentric ribs or concentric grooves or a mix of concentric ribs and grooves on one face thereof, and a nut which includes a bore having threads therein compatible with the threads of the spigot so that the nut can be screwed onto the spigot, the nut including a disc-like flange having concentric ribs or concentric grooves or a mix of concentric ribs and grooves on one face thereof, the pattern of ribs or grooves or ribs and grooves on the flanges being a mirror image one of the other so that when the nut is screwed onto the spigot, each rib enters a corresponding groove, the spacing between the ribs and grooves being such that sheet material between the two flanges is gripped with most force by the radially innermost rib/groove pair, the force exerted by each other rib/groove pair decreasing progressively to the outer rib/groove pair which grips the sheet material with least force. 
   
   
       2 . A filling and discharging structure as claimed in  claim 1 , wherein each of said flanges is of frustoconical form. 
   
   
       3 . A filling/discharging structure for a flexible tank, the structure having a series of concentric ribs for gripping sheet material between themselves and a backing plate, the configuration of the ribs being such that the pressure that each rib exerts on sheet material that is between itself and the backing plate increases progressively from the radially outer rib to the radially inner rib. 
   
   
       4 . A filling/discharging structure as claimed in  claim 3 , wherein the backing plate has grooves in it for receiving the ribs whereby the sheet material is, in use, deformed by each rib and forced into a respective groove. 
   
   
       5 . A flexible tank having a filling/discharging structure as claimed in  claim 1  secured to the flexible walling thereof, the walling of the tank being gripped by said ribs. 
   
   
       6 . A flexible tank having a filling/discharging structure as claimed in  claim 2  secured to the flexible walling thereof, the walling of the tank being gripped by said ribs. 
   
   
       7 . A flexible tank having a filling/discharging structure as claimed in  claim 3  secured to the flexible walling thereof, the walling of the tank being gripped by said ribs. 
   
   
       8 . A flexible tank having a filling/discharging structure as claimed in  claim 4  secured to the flexible walling thereof, the walling of the tank being gripped by said ribs.