AU2012202401A1

AU2012202401A1 - A Bunded Fuel Tank

Info

Publication number: AU2012202401A1
Application number: AU2012202401A
Authority: AU
Inventors: Damian Mccabe
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-04-26
Filing date: 2012-04-26
Publication date: 2013-03-28
Also published as: AU2012202401A2; GB201307751D0; GB2502198A; GB2502198B

Abstract

A bunded fuel tank for providing fuel for a range of products. The bunded fuel tank has an inner tank for storing fuel and an outer tank for containing spills preventing leakage of the fuel in the event of the integrity of the inner tank being compromised. The inner tank has a 5 lid with a primary fittings plate removably mounted on a inner tank primary hatchway on the inner tank. The primary fittings plate has a plurality of replaceable fittings for providing all of the control functionality associated with fuel disposable in the inner tank. 0, '-4 "4 =4 I-. cc 'C v-h _____ 'a _______ - 04 _____ I ______ "4

Description

AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION A BUNDED FUEL TANK The following statement is a description of the invention: 1 A BUNDED FUEL TANK The present invention relates to a bunded fuel tank and in particular a bunded fuel tank with improved functionality. 5 Fuel tanks for the transport and storage of fuel for use in remote sites are required by law to be bunded to significantly reduce the risk of spillage of harmful chemicals into the environment. Tanks of this nature are often designed for use with generators using the fuel to drive an engine for turning the alternator of an electrical power generator. The use of the fuel allows the provision of a main source of power where no mains is available or 10 provides back up power in the event of a mains power outage. Fuel tanks of this nature are complex requiring a range of fittings for delivering the fuel into the tank, dispensing the fuel under pressure to the diesel generator and controlling pressures and volumes of the volatile fuel as it is accessed and used in a wide range of operating conditions. These fittings are traditionally built into the lid of the internal tank which is welded to the sides of 15 the internal tank during manufacturing. A major problem with tanks of this type is replacement of fittings when there is a problem with the function of the relevant fitting. The existing tanks on the marketplace require the entire lid of the tank to be replaced in the event of a malfunctioning fitting. This means that the inner tank must be lifted out of the outer tank where possible and loaded 20 onto a trailer and brought to a metal works where the lid can be removed and the relevant fitting replaced or repaired if possible. Heavy welding equipment is required which is rarely available at the site where the fuel tanks are operating. Further problems arise with obtaining the spare fittings where it is not possible to repair the relevant fitting. The tank must also be drained as welding equipment cannot be safely used be used where a 25 volume of highly flammable fluid remains in the inner tank. It is an object of the present invention to obviate or mitigate the problem of complex expensive repair procedures for internal tanks of bunded fuel tanks.

2 Accordingly, the present invention provides a bunded fuel tank for providing fuel for a range of products, the bunded fuel tank having an inner tank for storing fuel and an outer tank for containing spills preventing leakage of the fuel in the event of the integrity of the inner tank being compromised, the inner tank having a lid with a primary fittings plate 5 removably mounted on a inner tank primary hatchway on the inner tank, the primary fittings plate having a plurality of replaceable fittings for providing all of the control functionality associated with fuel disposable in the inner tank. Advantageously, the replaceable fittings plate on the inner tank means that the fittings plate can be removed on site and replaced with spare parts using a number of 10 basic tools available at the location of the bunded fuel tank. Furthermore, the primary fitting plate covers the inner tank primary hatchway so that a single volume of space on the inner tank provides the primary fittings plate and the inner tank primary hatchway. The prior art devices provide a separate fitting plate and hatchway on different positions of the inner tank. 15 Preferably, the outer tank and the inner tank have a generally parallelepiped shape. Ideally, a secondary fittings plate is removably mounted on an inner tank secondary hatchway on the lid of the inner tank having a plurality of replacement fittings. Preferably, the primary and secondary fittings plates are pivotally coupled or bolted 20 to the lid of the inner tank. Advantageously, the replacement fittings on the secondary fittings plate allow a person immediate access to spare parts for a malfunctioning fitting on the primary fittings plate. Furthermore, where the specific situation calls for it, the secondary fittings hatch is fitted with a vent / fuelling secondary appliance. 25 Preferably, the primary fittings plate of the inner tank is removably mounted to the lid of the inner tank. Advantageously, where problems occur with the majority of the fittings on the primary fittings plate or where it would be easier to work on the primary 3 fittings plate of the inner tank in isolation from the bunded tank, the entire primary fittings plate can be decoupled from the lid and repaired or replaced locally or remotely. Preferably, the secondary fittings plate of the inner tank has a similar number and type of fittings as the primary fittings plate of the inner tank. 5 Ideally, the secondary fittings plate of the inner tank has the same number and type of fittings as the primary fittings plate of the inner tank. Advantageously, the primary fittings plate of the inner tank can be replaced with the secondary fittings plate of the inner tank where problems occur with the majority of the fittings on the primary fittings plate. 10 Preferably, the secondary fittings plate of the inner tank is removably mounted to the lid of the inner tank. Advantageously, where problems occur with the majority of the fittings on the primary fittings plate or where it would be easier to work on the primary fittings plate of the inner tank in isolation from the tank, the entire primary fittings plate and secondary fittings plate can be decoupled from the lid and repaired locally or remotely. 15 This would be useful, where welding equipment may be required which equipment could not be used proximal to a tank of highly explosive fuel for example. Preferably, the secondary fittings plate is pivotally mounted to the lid of the inner tank. Alternatively, the secondary fittings plate is bolted to the lid of the inner tank. 20 Preferably, the lid of the outer tank has a primary access hatch located for alignment with the primary fittings plate and primary hatchway of the inner tank. Advantageously, all of the repairs and/or replacement of the primary fittings plate on the inner tank can be carried out by opening the outer tank primary access hatch in alignment with the primary fittings plate and primary hatchway of the inner tank. 25 Ideally, the lid of the outer tank has a primary access hatch and a secondary access hatch for alignment with the primary and secondary fittings plates and hatchways of the inner tank.

4 Preferably, the primary access hatch is pivotally coupled to the lid of the outer tank. Ideally, the the primary access hatch is hinged to the lid of the outer tank. Preferably, the primary access hatch has a damping means for retarding the rate 5 of closure of the primary access hatch. Ideally, the damping means is mechanically coupled between the primary access hatch and the lid of the outer tank. Preferably, the damping means is a gas strut, preferably soft close. Ideally, an inner cavity of the inner tank has at least one baffle plate spanning 10 between two mutually opposing side walls. Preferably, the baffle plate has an aperture formed therein. Ideally, the inner cavity of the inner tank has a pair of spaced apart baffle plates spanning between two mutually opposing side walls. Preferably, the baffle plates have offset apertures formed therein. Advantageously, 15 the offset apertures control the flow of fluid through the inner tank as the inner tank is filled and emptied. This prevents the fuel sloshing and/or surging around the tank in an uncontrolled manner. Preferably, the baffle plates have chamfered/radiussed peripheral edges. Ideally, this provides gaps between the baffle plates and internal walls of the inner 20 tank allowing the flow of gas/vapour/liquid in the inner tank. Preferably, the offset apertures of the baffle plates have chamfered/radiussed internal corners. Advantageously, this prevents injury to operatives passing through the apertures during routine maintenance and servicing of tanks. Preferably, the inner tank has four lifting members mounted proximal to the top of 25 the inner tank, the lifting members having a first component part containing the engagement means for coupling to lifting ropes or chains, the first component part of the lifting members being angled towards the centre of the inner tank. Advantageously, the angular orientation of the first component part of the lifting members away from the 5 periphery of the inner tank towards the centre of the inner tank means that the four lifting chains or ropes of the lifting apparatus exert less force on the welded section between the lid and the side walls of the inner tank. Furthermore, this design of lifting members produce less stress on the lifting gear because the lifting members are orientated in the 5 same direction as the pulling force of the lifting equipment. Furthermore, because the lifting forces occur closer to the centre of gravity of the inner tank, there is less strain on the lifting gear. Ideally, a second component part of the lifting member extends at an obtuse angle from the first component part of the lifting member substantially in alignment with the edge 10 of the lid of the inner tank. Preferably, the inner tank has a means for collecting spilled fuel around one or more fittings hatchways. Advantageously, this allows the collection of any fuel dripping from a filling nozzle before or after filling or any other fuel inadvertently spilled in this area to be collected. 15 Ideally, the means for collecting spilled fuel is provided by a spill tray around the one or more fittings hatchways. Preferably, the lid of the outer tank has self locking means upon assembly. Ideally, the self locking means is activatable during assembly by lowering the lid into position on the upper lip of the outer tank. 20 Preferably, the self locking means of the lid comprises a plurality of adjustable locking means. Ideally, the plurality of adjustable locking means are provided by spring loaded locking pins formed for engagement with the upper lip of the outer tank. Preferably, one end of the spring loaded locking pins is tapered for causing lateral 25 displacement of the pin upon engagement with the upper lip of the outer tank. Ideally, the upper lip of the outer tank have a plurality of correspondingly located recesses formed thereon for receiving one end of the spring loaded locking pins.

6 Advantageously, as the tapered end of the spring loaded locking pins engage the upper lip of the outer tank, the pin is urged back against the biasing spring allowing that end of the locking pin to move past the upper lip of the outer tank. As the lid drops down onto the upper lip of the tank the tapered end of the spring loaded locking pins align with 5 the recesses of the upper lip and the spring urges the locking pins into the recesses locking the lid of outer tank into position. Advantageously, the lid of the outer tank can only be removed from inside which means that the lid can only be removed by someone with the ability/authority to open locking means on one of the access hatches of the lid of the outer tank. Furthermore, the 10 design of the outer tank is enhanced because all of the fixing means for attaching the lid to the outer tank are invisible during normal use of the tank. This feature is also likely to deter potential fuel thieves as it will be difficult for them to understand the exact mechanism used to couple the lid to the tank from outside the tank as these parts are hidden from view during normal use of the tank. 15 Preferably, the plurality of adjustable locking means are spaced out around the perimeter of the outer lid. Ideally, four adjustable locking means are provided proximal to the four corners of the outer lid. Preferably, the adjustable locking means are reachable from the access hatches. 20 Ideally, the spring loaded locking pins are slidably mounted on a bracket mechanically coupled to the underside of the lid of the outer tank. Preferably, the spring loaded locking pins are mounted in a protective sleeve welded to the underside of the lid of the outer tank. Preferably, at least part of the length of the vertical corners of the main body of the 25 outer tank are chamfered. Ideally, the major portion of the length of the vertical corners of the main body of the outer tank are chamfered.

7 Preferably, the chamfered vertical corners of the main body of the outer tank comprise an elongate vertical strip formed along the lateral edges of the two end wall panels of the main body of the outer tank, the elongate vertical strips forming the chamfered section. 5 Ideally, the free lateral edges of the elongate vertical strips have an elongate jointing strip formed for overlapping the outside vertical end portion of the adjoining side wall panel of the outer tank. Preferably, the upper and lower edges of the elongate jointing strip each have a panel extending there from. 10 Ideally, the panels of the elongate jointing strip extend out of the main plane of the elongate jointing strip towards the centre of the outer tank. Preferably, a first external weld joint is formed between the free end of the elongate jointing strip and the exposed vertical end portion of the adjoining side wall panel of the outer tank. 15 Ideally, a second internal weld joint is formed between the end of the elongate jointing strip attached to the elongate vertical strip and the vertical edge portion of the adjoining side wall panel of the outer tank. Ideally, the upper and lower edges of the end wall panels have an elongate folding strip. 20 Preferably, the upper and lower edges of the side wall panels have an elongate folding strip. Ideally, the upper and lower elongate folding strips of the end wall panels and the upper and lower elongate folding strips of the side wall panels extend out of the main plane of the end wall panels and side wall panels respectively towards the centre of the 25 outer tank. Preferably, the upper and lower elongate folding strips of the end wall panels and the upper and lower folding strips of the side wall panels extending out of the main plane of the end wall panels and side wall panels respectively towards the centre of the outer 8 tank in combination with the upper and lower panels of the elongate jointing strip extending out of the main plane of the elongate jointing strip towards the centre of the outer tank define a hexagonal arrangement on the upper and lower ends of the chamfered corners of the outer tank. 5 Ideally, the upper and lower edges of the elongate vertical strip defining the chamfered section of the corner have no panels extending there from defining a triangular gap between the upper and lower elongate folding strips of the end wall panels and the upper and lower panels of the elongate jointing strip. Preferably, the hexagonal arrangement on the upper and lower ends of the 10 chamfered corners of the outer tank is completed by welding a triangular portion into this gap. Advantageously, the hexagonal arrangement on the upper and lower ends of the chamfered corners of the outer tank provides better leak protection with more folding while retaining some welded joints. 15 Ideally, both end sections of the lid of the outer tank has a folded flap protruding downwardly out of the main plane of the lid. Preferably, both lateral sections of the lid of the outer tank have wing sections. Advantageously, the wing sections allow the central part of the one piece lid to be recessed relative to the wings so that the access hatches can be located in the recess 20 without interfering with another bunded fuel tank stacked above. Ideally, a stiffening panel is welded to the profile defined by the folded flap on the end sections of the lid and the end section of the wing at each of the four corners of the lid of the outer tank. Advantageously, the folded flap reduces the amount of welding required to form an 25 end section on the lid. Ideally, the access hatches on the outer lid have handle means on the opening ends of the hatches.

9 Preferably, the free end of the handles extend away from the main plane of the lid in the closed position. Advantageously, this mitigates against an operator nipping or trapping their hand between the handle and the lid when closing the access hatch. Preferably, the primary opening in the lid of the outer tank covered by the primary 5 access hatch extends as close to the of the edge of the lid of the tank as possible. Ideally, the fittings on the primary access hatch of the inner tank comprise at least one filler conduit and cap. Preferably, the fittings comprise a plurality of suction conduits and caps. Ideally, the fittings comprise a plurality of vents and a plurality of return conduits 10 and caps. Preferably, the fittings comprise a fuel gauge. Ideally, the fittings on the secondary access hatch of the inner tank can comprise the same or similar fittings. Preferably, the outer tank has one or more apertures for receiving fuel pipe or 15 conduits. Advantageously, this allows the access hatches to be closed and locked while fuel is delivered or removed to or from the inner tank. Ideally, the inner tank is removably mountable within the outer tank. This had major technical advantages for servicing and repair. The invention will now be described with reference to the accompanying drawings 20 which shows by way of example only one embodiment of an apparatus in accordance with the invention. In the drawings: Figure 1 is a perspective view of a bunded tank; Figure 2 is an end view of the bunded tank; Figure 3 is a side elevation view of the bunded tank; 25 Figure 4 is a second end view of the bunded tank; Figure 5 is a section view taken along A-A of Figure 3; Figure 6 is a top plan view of the bunded tank; Figure 7 is a section view taken along B-B of Figure 6; 10 Figure 8 is a perspective view of an inner tank; Figure 9 is an end view of the inner tank; Figure 10 is a side elevation view of the inner tank; Figure 11 is a second end view of the inner tank; 5 Figure 12 is a section view taken along A-A of Figure 10; Figure 13 is a top plan view of the inner tank; Figure 14 is a section view taken along B-B of Figure 13; Figure 15 is a perspective view of the lid of the outer tank; Figure 16 is a detail A of a spring bolt arrangement shown in figure 15; 10 Figure 17 is a second perspective view of the lid of the outer tank; Figure 18 is a top plan view of the lid of the outer tank; Figure 19 is an end view of the lid of the outer tank; Figure 20 is a perspective view of the outer tank; Figure 21 is a detail C of a corner section of the outer tank shown in figure 20; 15 Figure 22 is a detail B of a bottom corner section of the outer tank shown in figure 20; Figure 23 is a detail A of a top corner section of the outer tank shown in figure 20; Figure 24 is a perspective view of the lid of the outer tank; Figure 25 is a perspective view of the lid of the outer tank with the corner end 20 panels removed; Figure 26 is a top plan view of the lid of the outer tank; Figure 27 is a section view taken along A-A of Figure 26; Figure 28 is a top plan view of the primary access hatch; Figure 29 is a side view of the primary access hatch; 25 Figure 30 is a perspective view of the primary access hatch; In the drawing, there is shown a bunded fuel tank indicated generally by the reference numeral 1 for providing fuel for a range of products. The bunded fuel tank 11 having an inner tank 2 see Figures 8 to 14 for storing fuel and an outer tank 3 see especially Figures 1 to 7 for containing spills preventing leakage of the fuel in the event of the integrity of the inner tank 2 being compromised. The inner tank 2 has a lid 4 with a primary fittings plate 5 removably mounted on a primary hatchway allowing an operator 5 control of the delivery, removal or maintenance of fuel in or from an inner cavity 32 see Figure 12 of the inner tank 2. The primary fittings plate 5 has eleven replaceable fittings 6 to 16 shown as exemplary only, see Figures 13 and 8 for providing all of the control functionality associated with the fuel in the inner tank 2. Advantageously, the replaceable primary fittings plate 5 of the inner tank 2 means 10 that the fittings 6 to 16 can be removed on site and replaced with spare parts using a number of basic tools available at the location of the bunded fuel tank 1. A secondary fittings plate 21 removably mounted on a secondary hatchway is provided on the lid 4 of the inner tank 2 which has four replacement fittings 22 to 25. The replacement fittings 22 to 25 on the secondary fittings plate 21 allow a person immediate access to spare parts 15 for a malfunctioning fitting 6 to 16 on the primary fittings plate 5. Furthermore, where the specific situation calls for it, the secondary fittings plate 21 is fitted with a vent / fuelling secondary appliance. The front cover of the outer tank 3 has two apertures 301 for receiving pipes or conduits. Advantageously, this allows the access hatches 44, 45 to be closed and locked while fuel is delivered or removed to or from the fittings plates 5, 21 of 20 the inner tank 4 through the apertures 301. The outer tank 3 and the inner tank 2 of the bunded fuel tank 1 have a generally parallelepiped shape. The outer tank 3 has four heavy duty bi-directional fork lifting pockets 26 see Figs 1 to 5 and four galvanized lifting lugs 27 with four stacking brackets 28 on the upper corners of the lid 31 of the outer tank 3. 25 The lid 31 of the outer tank 3 has a primary access hatch 44 located for alignment with the primary fittings plate 5 and primary hatchway of the inner tank 2. Advantageously, all of the repairs and/or replacement of the primary fittings plate 5 of the inner tank 2 can be carried out by opening the primary access hatch 44 in alignment with the primary 12 fittings plate 5 and primary hatchway of the inner tank 2. The lid 31 of the outer tank 3 has a secondary access hatch 45 for alignment with the secondary fittings plate 21 of the inner tank 2. The primary fittings plate 5 of the inner tank 2 is removably mounted to the lid 4 of the inner tank 2. Advantageously, where problems occur with the majority of the fittings 6 5 to 16 on the primary fittings plate 5 or where it would be easier to work on the primary fittings plate 5 of the inner tank 2 in isolation from the bunded tank 1, the entire primary fittings plate 5 can be decoupled from the lid 4 and repaired or replaced locally or remotely. The primary fittings plate 5 is pivotally coupled or bolted to the lid 4. Advantageously, the primary fittings plate 5 of the inner tank 2 can be replaced 10 with the secondary fittings plate 21 of the inner tank 2 where problems occur with the majority of the fittings on the primary fittings plate 5 and vice versa. The secondary fittings plate 21 of the inner tank 2 is removably mounted to the lid 4 of the inner tank 2. Advantageously, where problems occur with the majority of the fittings 6 to 16 on the primary fittings plate 5 or where it would be easier to work on the primary fittings plate 5 of 15 the inner tank 2 in isolation from the bunded tank 1, the entire primary fittings plate 5 and secondary fittings plate 21 can be decoupled from the lid 4 and repaired locally or remotely. This would be useful, where welding equipment may be required which equipment could not be used proximal to a tank 1 of highly explosive fuel for example. The secondary fittings plate 21 is also pivotally mounted to the lid 4 of the inner tank 2. 20 Alternatively, the secondary fittings plate 21 is bolted to the lid 4 of the inner tank 2. The secondary fittings plate 21 of the inner tank 2 can have a similar number and type of fittings as the primary fittings plate 5 of the inner tank 2 although the secondary fittings plate 21 shown in the drawings only has four of the most crucial replacement fittings 22 to 25. 25 The primary access hatch 44 of the outer tank 3 is pivotally coupled to the lid 31 of the outer tank 3. The primary access hatch 44 has a damping member 46 see fig 16 for retarding the rate of closure of the primary access hatch 44. The damping member 46 is 13 mechanically coupled between the primary access hatch 44 and the lid 31 of the outer tank 3. The damping member 46 is a gas strut 46, preferably soft close. The inner cavity 32 see figure 5 and 12 of the inner tank 2 has a pair of spaced apart baffle plates 33 spanning between two mutually opposing side walls 34. The baffle 5 plates 33 have offset apertures 35 formed therein. Advantageously, the offset apertures 35 control the flow of fluid through the inner tank 2 as the inner tank 2 is filled and emptied. This prevents the fuel sloshing and/or surging around the tank 2 in an uncontrolled manner. The baffle plates 35 have chamfered/radiussed peripheral edges 36. This provides gaps 37 between the baffle plates 35 and internal walls of the inner tank 2 10 allowing the flow of gas/vapour/liquid in the inner tank 2. The offset apertures 35 of the baffle plates 33 have chamfered/radiussed internal corners 41. Advantageously, this prevents injury to operatives passing through the apertures 35 during routine maintenance and servicing of tanks 1. The inner tank 2 has four lifting members 51 see figs 8 to 12 mounted proximal the 15 top of the inner tank 2. The lifting members 51 having a first component part 52 containing the engagement hole 53 for coupling to lifting ropes or chains. The first component part 52 of the lifting members 51 being angled towards the centre of the inner tank 2. Advantageously, the angular orientation of the first component part 52 of the lifting members 51 away from the periphery of the inner tank 2 towards the centre of the inner 20 tank 2 means that the four lifting chains or ropes of the lifting apparatus (not shown) exert less force on the welded section between the lid 4 and the side walls of the inner tank 2. Furthermore, this design of lifting members 51 produce less stress on the lifting gear because the lifting members 51 are orientated in the same direction as the pulling force of the lifting equipment. Furthermore, because the lifting forces occur closer to the centre of 25 gravity of the inner tank 2, there is less strain on the lifting gear. A second component part 54 of the lifting member 51 extends at an obtuse angle from the first component part 52 of the lifting member 51 substantially in alignment with the edge of the lid 4 of the inner tank 2. The inner tank 2 has an arrangement 55 see Fig 14 8 for collecting spilled fuel around the primary and secondary fittings plates 5 and 21. Advantageously, this allows the collection of any fuel dripping from a filling nozzle before or after filling or any other fuel inadvertently spilled in this area to be collected. The arrangement for collecting spilled fuel is provided by a spill tray 55 around the fittings 5 plates 5, 21 and hatchways. The lid 31 of the outer tank 3 has a self locking arrangement upon assembly indicated generally by the reference numeral 61, see especially Figures 15 to 19. The self locking arrangement 61 is activatable during assembly by lowering the lid 31 into position onto the upper lip 63 of the outer tank 3, see Fig 20. The self locking arrangement 61 of 10 the lid has four adjustable locking members 64. The adjustable locking members 64 are provided by spring loaded locking pins 65 formed for engagement with the upper lip 63 of the outer tank 3. One end 67 of the spring loaded locking pins 65 is tapered for causing lateral displacement of the pin 65 upon engagement with the upper lip 63 of the outer tank 3. The upper lip 63 of the outer tank 3 has four correspondingly located recesses 66 see 15 Figure 20 formed thereon for receiving the tapered end 67 of the spring loaded locking pins 65. Advantageously, as the tapered end 67 of the spring loaded locking pins 65 engage the upper lip 63 of the outer tank 3, the pin 65 is urged back against a biasing spring 68 allowing the tapered end 67 of the locking pin 65 to move past the upper lip 63 20 of the outer tank 3. As the lid 31 drops down onto the upper lip 63 of the outer tank 3 the tapered end 67 of the spring loaded locking pins 65 align with the recesses 66 of the upper lip 63 and the spring 68 urges the locking pins 65 into the recesses 66 locking the lid 31 of outer tank 3 into position. Advantageously, the lid 31 of the outer tank 3 can only be removed from inside 25 which means that the lid 31 can only be removed by someone with the authority to open one of the access hatches 44, 45 of the lid 31 of the outer tank 3. Furthermore, the design of the outer tank 3 is enhanced because all of the fixing members 61 for attaching the lid 31 to the outer tank 3 are invisible during normal use of the tank 1. This feature is also 15 likely to deter potential fuel thieves as it will be difficult for them to understand the exact mechanism used to couple the lid 31 to the tank 1 from outside the tank 1 as these parts are hidden from view during normal use of the tank 1. The plurality of adjustable locking members 64 are spaced out around the perimeter of the outer lid 31. The four adjustable 5 locking members 64 are provided proximal to the four corners of the outer lid 31. The spring loaded locking pins 65 are slidably mounted on a u-shaped bracket 69 mechanically coupled to the underside of the lid 31 of the outer tank 3. Referring to the drawings and now to Figures 20 to 23, at least part of the length of the vertical corners 71 of the main body of the outer tank 3 are chamfered. The major 10 portion of the length of the vertical corners 71 of the main body of the outer tank 3 are chamfered. The chamfered vertical corners 71 of the main body of the outer tank 3 have an elongate vertical strip 72 formed along the lateral edges 73 of the two end wall panels 74 of the main body of the outer tank 3 and these elongate vertical strips 72 form the chamfered section. The free lateral edges 75 of the elongate vertical strips 72 have an 15 elongate jointing strip 76 formed for overlapping the outside vertical end portion 77 of the adjoining side wall panel 78 of the outer tank 3. The upper 81 and lower edges 82 of the elongate jointing strip 76 each have a panel 83 extending there from. The panels 83 of the elongate jointing strip 76 extend out of the main plane of the elongate jointing strip 76 towards the centre of the outer tank 3. 20 A first external weld joint 85 is formed between the free end of the elongate jointing strip 76 and the exposed vertical end portion 77 of the adjoining side wall panel 78 of the outer tank 3. A second internal weld joint is formed between the end of the elongate jointing strip 76 attached to the elongate vertical strip 72 and the vertical edge of the adjoining side wall panel 78 of the outer tank 3. The upper and lower edges 91, 92 of the 25 end wall panels 74 have an elongate folding strip 93, 94. The upper and lower edges 95, 96 of the side wall panels 78 have an elongate folding strip 97, 98. The upper and lower elongate folding strips 93, 94 of the end wall panels 74 and the upper and lower elongate folding strips 97, 98 of the side wall panels 78 extend out of the main plane of the end wall 16 panels 74 and side wall panels 78 respectively towards the centre of the outer tank 3. The upper and lower elongate folding strips 93, 94 of the end wall panels 74 and the upper and lower folding strips 97, 98 of the side wall panels 78 extending out of the main plane of the end wall panels 74 and side wall panels 78 respectively towards the centre of 5 the outer tank 3 in combination with the upper and lower panels 83 of the elongate jointing strip 76 extending out of the main plane of the elongate jointing strip 76 towards the centre of the outer tank 3 define a hexagonal arrangement on the upper and lower ends of the chamfered corners 71 of the outer tank 3. The upper and lower edges of the elongate vertical strip 72 defining the chamfered 10 section of the corner 71 have no panels extending there from defining a triangular gap 101 between the upper and lower elongate folding strips 93, 94 of the end wall panels 74 and the upper and lower panels 83 of the elongate jointing strip 76. The hexagonal arrangement on the upper and lower ends of the chamfered corners 71 of the outer tank 3 is completed by welding a triangular portion 102 into this gap 101. 15 Advantageously, the hexagonal arrangement on the upper and lower ends of the chamfered corners 71 of the outer tank 3 provides better leak protection with more folding while retaining some welded joints. Referring to the drawings and now to Figures 24 to 27, both end sections 111 of the lid 31 of the outer tank 3 has a folded flap 112 protruding downwardly out of the main 20 plane of the lid 31. Both lateral sections 113 of the lid 31 of the outer tank 3 have wing sections 114 forming a one piece lid 31 together forming a one piece lid 31. A stiffening panel 115 is welded to the profile defined by the folded flap 112 on the end sections 111 of the lid 31 and the end section 116 of the wing section 114 at each of the four corners of the lid 31 of the outer tank 3. Advantageously, the folded flap 112 reduces the amount of 25 welding required to form an end section on the lid 31. Referring to the drawings and now to Figures 28 to 30, the access hatch 44 on the outer lid 3 have a handle 121 on the opening ends 122 of the hatch 44. The free end of the handle 121 extends away from the main plane of the lid 31 in the closed position.

17 Advantageously, this mitigates against an operator nipping or trapping their hand between the handle 121 and the lid 31 when closing the access hatch 44, 45. The primary opening 124 in the lid 31 of the outer tank 3, see figure 24 covered by the primary access hatch 44 extends as close to the edge 111 of the lid 31 of the tank 3 as possible. Advantageously, 5 this provides the greatest amount of clearance between the inner tank 2 and the primary opening 124 of the lid 31 of the outer tank 3 as a person climbs down into the space defined between the inner tank 2 and the opening 124 in the lid 31 of the outer tank 3. The fittings 6 to 16 on the primary fittings plate 5 see Figure 8 are a filler conduit and cap 6, 3 suction conduits and caps 7 to 9, two vents 10, 11, three return conduits and 10 caps 12, 13, 14, a fuel gauge 15 and a spare fitting 16. Similar functional fittings are provided on the secondary fittings plate 21. In relation to the detailed description of the different embodiments of the invention, it will be understood that one or more technical features of one embodiment can be used in combination with one or more technical features of any other embodiment where the 15 transferred use of the one or more technical features would be immediately apparent to a person of ordinary skill in the art to carry out a similar function in a similar way on the other embodiment. In the preceding discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a 20 parameter, coupled with an indication that one of the said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value. 25 The features disclosed in the foregoing description or the following drawings, expressed in their specific forms or in terms of a means for performing a disclosed function, or a method or a process of attaining the disclosed result, as appropriate, may 18 separately, or in any combination of such features be utilised for realising the invention in diverse forms thereof as defined in the appended claims.

Claims

1. A bunded fuel tank for providing fuel for a range of products, the bunded fuel tank having an inner tank for storing fuel and an outer tank for containing spills 5 preventing leakage of the fuel in the event of the integrity of the inner tank being compromised, the inner tank having a lid with a primary fittings plate removably mounted on an inner tank primary hatchway on the inner tank, the primary fittings plate having a plurality of replaceable fittings for providing all of the control functionality associated with fuel disposable in the inner tank. 10

2. A bunded fuel tank as claimed in claim 1, wherein a secondary fittings plate is removably mounted on an inner tank secondary hatchway on the lid of the inner tank having a plurality of replacement fittings.

3. A bunded fuel tank as claimed in claim 1 and 2, wherein the primary and secondary fittings plates are pivotally coupled or bolted to the lid of the inner tank. 15

4. A bunded fuel tank as claimed in any one of the preceding claims, wherein a lid of the outer tank has a primary access hatch located for alignment with the primary fittings plate and primary hatchway of the inner tank.

5. A bunded fuel tank as claimed in claim 4 when dependent on claim 2 or 3, wherein the lid of the outer tank has a primary access hatch and a secondary access hatch 20 for alignment with the primary and secondary fittings plates and hatchways of the inner tank.

6. A bunded fuel tank as claimed in claim 4 or 5, wherein the primary access hatch has a damping means for retarding the rate of closure of the primary access hatch.

7. A bunded fuel tank as claimed in any one of the preceding claims, wherein an 25 inner cavity of the inner tank has at least one baffle plate spanning between two mutually opposing side walls.

8. A bunded fuel tank as claimed in claim 7, wherein the baffle plate has an aperture formed therein. 20

9. A bunded fuel tank as claimed in claim 7 or 8, wherein the inner cavity of the inner tank has a pair of spaced apart baffle plates spanning between two mutually opposing side walls

10. A bunded fuel tank as claimed in claim 9, wherein the baffle plates have offset 5 apertures formed therein.

11. A bunded fuel tank as claimed in any one of the preceding claims, wherein the inner tank has four lifting members mounted proximal to the top of the inner tank, the lifting members having a first component part containing the engagement means for coupling to lifting ropes or chains, the first component part of the lifting 10 members being angled towards the centre of the inner tank.

12. A bunded fuel tank as claimed in claim 11, wherein a second component part of the lifting member extends at an obtuse angle from the first component part of the lifting member substantially in alignment with the edge of the lid of the inner tank.

13. A bunded fuel tank as claimed in any one of the preceding claims, wherein the 15 inner tank has a means for collecting spilled fuel around one or more fittings hatchways.

14. A bunded fuel tank as claimed in any one of the preceding claims, wherein a lid of the outer tank has self locking means upon assembly.

15. A bunded fuel tank as claimed in any one of the preceding claims, wherein at least 20 part of the length of vertical corners of the main body of the outer tank are chamfered.

16. A bunded fuel tank as claimed in claim 15, wherein the major portion of the length of the vertical corners of the main body of the outer tank are chamfered.

17. A bunded fuel tank as claimed in claim 15 or 16, wherein the chamfered vertical 25 corners of the main body of the outer tank comprise an elongate vertical strip formed along the lateral edges of the two end wall panels of the main body of the outer tank, the elongate vertical strips forming the chamfered section. 21

18. A bunded fuel tank as claimed in claim 17, wherein the free lateral edges of the elongate vertical strips have an elongate jointing strip formed for overlapping the outside vertical end portion of the adjoining side wall panel of the outer tank.

19. A bunded fuel tank as claimed in claim 14 and claims 15 to 18 when dependent on 5 claim 14, wherein both end sections of the lid of the outer tank has a folded flap protruding downwardly out of the main plane of the lid.

20. A bunded fuel tank as claimed in claim 19, wherein both lateral sections of the lid of the outer tank have wing sections.

21. A bunded fuel tank as claimed in claim 19 and 20, wherein a stiffening panel is 10 welded to the profile defined by the folded flap on the end sections of the lid and the end section of the wing at each of the four corners of the lid of the outer tank.

22. A bunded fuel tank as claimed in claim 5, wherein the access hatches on the outer lid have handle means on the opening ends of the hatches, the free end of the handles extend away from the main plane of the lid in the closed position. 15

23. A bunded fuel tank as claimed in any one of the preceding claims, wherein the outer tank has one or more apertures for receiving fuel pipe or conduits.

24. A bunded fuel tank as claimed in any one of the preceding claims, wherein the inner tank is removably mountable within the outer tank. 20