Fuel tanks

Abstract

A bunded tank is provided which includes inner and outer walls, wherein the inner and outer walls, when the tank is viewed in transverse cross-section, define a substantially rectangular shape, wherein each inner and outer wall has an at least partially convex profile, wherein adjacent sides of the inner and outer walls are connected by rounded corners, and wherein the inner and outer walls are arranged with respect to one another to create an inner tank and an outer tank.

1 . A bunded tank which includes inner and outer walls, comprising:
 the inner and outer walls, when the tank is viewed in transverse cross-section, define a substantially rectangular shape wherein each inner and outer wall has an at least partially convex profile:   adjacent sides of the inner and outer walls are connected by rounded corners;   the inner and outer walls are arranged with respect to one another to create an inner tank and an outer tank; and   the SRS of the outer wall is substantially monocoque.   
     
     
         2 . The bunded tank as claimed in  claim 1 , wherein the outer wall is made by way of one or more sections, including:
 at least one centre section; and   at least two end cap sections.   
     
     
         3 . The bunded tank of  claim 1 , wherein the tank includes one or more plug welds or other joins between the inner and outer walls at one or more locations along the length of the tank. 
     
     
         4 . The bunded tank of  claim 2 , wherein the end cap sections of the tank also include an at least partially convex profile. 
     
     
         5 . The bunded tank of  claim 1 , wherein the tank includes one or more isoblock connectors on a lower side of the tank. 
     
     
         6 . The bunded tank of  claim 5 , wherein the one or more isoblock connectors are located symmetrically on the bottom of the tank. 
     
     
         7 . The bunded tank of  claim 5 , wherein one or more isoblock connectors are located on an upper side of the tank. 
     
     
         8 . The bunded tank of  claim 5 , wherein one or more of the isoblock connectors are located on outer corners of the tank. 
     
     
         9 . The bunded tank of  claim 5 , wherein one or more of the isoblock connectors are located at the ends of the tank. 
     
     
         10 . The bunded tank of  claim 5 , wherein one or more of the isoblock connectors are attached to the tank by way of support struts or the like. 
     
     
         11 . The bunded tank of  claim 1 , wherein the tank includes one or more lower support members. 
     
     
         12 . The bunded tank of  claim 11 , wherein the lower support members are in the form of two parallel supports running substantially the length of the tank. 
     
     
         13 . The bunded tank of  claim 12 , wherein the lower support members comprise a plurality of supports running in either a longitudinal, a transverse direction or a combination of longitudinal and transverse directions. 
     
     
         14 . The bunded tank as claimed in  claim 11 , wherein lower isoblock connectors are integral with the lower support members. 
     
     
         15 . A method of constructing a bunded fuel tank having inner and outer walls, wherein each inner or outer wall has an at least partially convex profile;
 wherein adjacent sides of the inner and/or outer walls are connected by rounded corners; and   wherein the inner and outer walls are arranged with respect to one another to create an inner tank and an outer tank,   the method comprising:   a) pre-forming one or more standard sheets of material into one or more SRS sections for the inner walls;   b) forming one or more standard sheets of material into end caps for the inner wall;   c) pre-forming one or more standard sheets of material into one or more SRS sections for the outer wall;   d) forming one or more standard sheets of material into end caps for the outer wall;   e) joining the one or more SRS sections forming the inner wall together to form a single inner SRS tube;   f) joining the one or more SRS sections forming the outer wall together to form a single outer SRS tube forming an enclosure about at least a portion of the inner SRS tube;   g) joining the end caps for the inner wall to the inner SRS tube;   h) joining the end caps for the outer wall to the outer SRS tube; and   i) joining one or more lower support members to the lower surface of the SRS tank.   
     
     
         16 . The method of  claim 15  further including the step of attaching one or more isoblock connectors to the lower supports of the SRS tank. 
     
     
         17 . The method of  claim 15  further characterised in that the portion of the inner tank that is enclosed by the outer SRS tube in method step f) comprises substantially three sides and both ends of the inner SRS tube. 
     
     
         18 . The method of constructing a fuel tank as claimed in  claim 15 , including:
 j) forming one or more apertures through the portion of the inner SRS tube that is not enclosed by the outer SRS tube.   
     
     
         19 . The method of  claim 15  wherein the sheet material is plate steel. 
     
     
         20 . The method of  claim 19  wherein joining the plate steel sheets includes welding. 
     
     
         21 . A method of constructing a bunded fuel tank having inner and outer walls, comprising:
 forming inner and outer walls which are SRS when viewed in transverse cross section;   each inner and outer wall has an at least partially convex profile;   adjacent sides of the inner and outer walls are connected by rounded corners; and   the inner and outer walls are arranged with respect to one another to create an inner tank and an outer tank.   
     
     
         22 . (canceled) 
     
     
         23 . (canceled)