AU710621B2 - Dual chamber fluid storage vessel - Google Patents

Description

WO 97/09561 PCT/AU96/00544 DUAL CHAMBER FLUID STORAGE VESSEL The present invention relates to fluid storage vessels such as fuel vessels which, while adapted for automotive use, may be used in other areas, and is particularly concerned with a dual chamber fluid storage vessel. While both chambers of the vessel may be adapted to receive non-pressurised fluid such as petrol or diesel, the dual chamber vessel of the present invention may be such that at least one of the chambers is adapted to receive a pressurized fluid, whether liquid or gas, such as pressurized petrol or other liquid, LPG, CNG, compressed air or other compressed gas and the present invention will be primarily described with this in mind.

Conventional pressurized liquid fuel cylinders for automotive use are constructed in three pieces with two dished ends welded circumferentially to a cylindrical portion which is formed by rolling plate steel and welding the opposed edges together. Such a cylinder is normally provided in addition to an original equipment petrol tank and may occupy a substantial amount of space in the boot of a vehicle or beneath the floor of the vehicle.

In some small cars there is insufficient room to fit such a cylinder of requisite size.

It has been previously proposed to provide an automobile pressurized fuel vessel which is shaped and sized to fit into a well in the floor of the boot of the automobile which would otherwise accommodate a spare wheel for the automobile so as to reduce the volume of space in the boot occupied by the vessel. GB 2095808 discloses a toroidal vessel and NL 7703630 discloses a somewhat squashed substantially toroidal vessel in which the axis of the vessel is sealed off by a sleeve to define a toroidal chamber for the fuel.

An improved pressurized fuel vessel allowing greater internal volume is described in International Patent Application W092/06324 in my name in which there is proposed a pressurized fuel vessel for automotive or other use having opposed axial end walls connected at or adjacent an outer periphery to define an enclosed chamber, the vessel being of greater diametrical dimension than axial dimension, with internal reinforcing WO 97/09561 PCT/AU96/00544 -2extending between the opposed axial end walls, the internal reinforcing comprising at least one reinforcing wall which extends within the chamber at least substantially about an axis of the vessel intermediate the axis and the outer periphery, and the at least one reinforcing wall being adapted to permit pressurized fuel to flow between portions of the chamber respectively disposed radially inwardly and radially outwardly thereof.

A still further improved pressurized fuel vessel is described in WO95/02152 in my name in which there is proposed a pressurized fuel vessel for automotive or other use having opposed axial end walls connected at or adjacent an outer periphery to define an enclosed chamber, the vessel being of greater diametrical dimension than axial dimension, and wherein internal reinforcing extends between the opposed axial end walls, the internal reinforcing comprising a reinforcing wall which extends within the chamber intermediate the axis and the outer periphery and the reinforcing wall being adapted to permit pressurized fuel to flow between portions of the chamber respectively disposed radially inwardly and radially outwardly thereof. The vessel is formed of a preformed enclosure having opposed ends and a peripheral wall defining, respectively, radially inner portions of the opposed axial end walls of the vessel and the reinforcing wall whereby the enclosure forms the radially inwardly disposed portion of the chamber, and an annular portion secured to the enclosure to form the radially outwardly disposed portion of the chamber, the annular portion defining radially outer portions of the opposed axial end walls and the outer periphery of the vessel. The reinforcing wall having at least one opening therethrough to permit the fuel flow between the chambers.

All of the aforementioned pressurized fluid storage vessels provide storage for a single fuel. There is no separate reservoir for a secondary volume of the fuel and a second fuel tank will normally be required for storing a non-pressurized fuel such as petrol or diesel.

According to the present invention there is provided a fluid storage vessel for automotive or other use having opposed end walls connected at or adjacent an outer periphery and an annular internal wall extending between the opposed end walls whereby said vessel comprises a first inner chamber defined by inner portions of the opposed end walls of the WO 97/09561 PCT/AU96/00544 -3vessel and the internal wall and a second annular chamber around the first chamber defined by the internal wall and outer portions of the opposed end walls connected at the outer periphery of the vessel, said internal wall preventing fluid flow between the chambers, and wherein each chamber is provided with a respective fluid flow connection to the exterior.

By the present invention, two separate storage chambers are conveniently provided in the one fluid storage vessel which may be used for the same non-pressurized or pressurized fluid or, respectively, for a non-pressurized fluid and a pressurized fluid. In the first arrangement, one of the chambers may provide storage for a secondary or emergency volume of a fuel stored in the other chamber. In the second arrangement, the fluid storage vessel of the invention may obviate the need for entirely separate storage tanks for pressurized and non-pressurized fuels. In the second arrangement it is preferred that the non-pressurized fuel be stored in the first inner chamber.

In another embodiment, the fluid storage vessel may be used for storing one or more non-fuel fluids. For example, one of the chambers may be used for storing compressed air or other gas while the other chamber is used for storing a different fluid. In a particular embodiment, the different fluid is a fuel for a compressor which compresses the air or other gas supplied to the one chamber. In this embodiment the compressed air or other gas in the one chamber may be used to pressurize the fuel in the other chamber, for example to provide lift to the fuel from the vessel to the compressor. A switching valve device may be used to ensure that the desired pressure is provided in the fuel chamber, usually the inner chamber.

The fluid flow connections provided for each of said two chambers of the vessel may incorporate valves or other fluid inlet and outlet means of any appropriate known type.

Other known devices, such as sensors for determining the volume of fluid remaining in the chambers, may also be provided. The specific fluid flow connections and other devices do not form part of the present invention so will not be described in detail.

WO 97/09561 PCT/AU96/00544 -4- The fluid flow connections may conveniently be provided in the respective portions of the end walls. If the fluid flow connection to the first inner chamber is provided in the internal wall, it may include passage means which exit through, for example, an outer peripheral wall of the vessel.

Where the fluid storage vessel in accordance with the invention is used in an automobile, it may advantageously be sized to fit into a spare wheel well in the boot of the automobile. As is well known, the well may be provided in the floor of the boot or, for example, in a wing of the automobile in which case the vessel would likely only be partially received in the well in an upright manner. Alternatively, the fuel vessel may be supported externally, as is well known in both cars and trucks.

The vessel preferably has a substantially circular cross-section (optionally with a segmental portion removed therefrom to allow the vessel to fit better in a well in a wing of an automobile) and the term "diametrical dimension" used hereinafter should be construed in relation to the smallest circle within which the vessel can be located.

However, the cross-section may be rectangular (preferably with rounded corners) or any other non-circular cross-section, such as irregular, ellipsoidal or other oval shape, if desired. The vessel preferably has at least one diametrical dimension which is greater than the axial dimension, but otherwise may be of any suitable cross-section, including the irregular shapes which are commonly used today for automobile fuel tanks, for example, which fit under the car floor pan beneath the back seat or between the rear wheels. An axis about which the internal wall extends is conveniently the central axis of the aforementioned smallest circle, but not necessarily, depending upon the shape of the annular chamber. Thus, the term "annular chamber" should be construed merely as meaning that that chamber extends about the internal wall. The annular internal wall may itself have any suitable cross-section, but is preferably circular and most preferably at least substantially cylindrical.

Particularly where the fluid storage vessel is to be used to store pressurized fluid such as LPG, the internal wall may act as internal reinforcing means to reduce the minimum WO 97/09561 PCT/AU96/00544 permissible thickness of the opposed end walls of the vessel. Since the pressures in the two chambers of the vessel will usually be different, the pressures applied to the internal wall from each chamber will also be different. The same will also be true for the pressures on either side of the walls defining the exterior surfaces of the outer annular chamber when pressurized fluid is stored in that chamber, but, because of the greater surface area of the walls defining the exterior surfaces of the outer annular chamber compared to the surface area of the internal wall, less force may be applied to those exterior surface walls than to the internal wall. Accordingly, particularly when the inner chamber is to be used to store a non-pressurized or lightly pressurized fluid and the outer chamber is to be used for storing a pressurized fluid, it is advantageous if the internal wall is formed of a material having greater strength than material defining the exterior surfaces of the outer annular chamber. This may be achieved by forming the internal wall of thicker material or, for example, of higher grade material.

The fluid storage vessel may include additional internal reinforcing means to the internal wall, for example another reinforcing wall (through which fluid may flow or may be prevented from flowing) and/or one or more columns extending between the end walls.

These and other optional features which may be adopted with the present invention are described in my earlier patent application WO92/06324 which is incorporated herein by reference.

The outer periphery of the vessel is most preferably defined by a substantially axially extending outer wall which may be strengthened if necessary by, for example, giving it a rippled configuration or by making it externally convex.

The fluid storage vessel is conveniently formed in steel, for example, stainless steel or any other appropriate grade of steel, or in any other suitable material such as aluminium which may be reinforced with, for example, glass, carbon or Kevlar fibre reinforced resin. The inner and/or outer portions of the opposed end walls may be convex or otherwise shaped to increase their strength. Advantageously, the second annular chamber comprises two opposed shell portions defining the outer portions of the end walls and the

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WO 97/09561 PCT/AU96/00544 -6outer periphery, the shell portions preferably being substantially identical and being secured to each other along an axially central diametrical plane of the vessel.

In one embodiment, the fluid storage vessel may comprise a preformed substantially toroidal enclosure which defines the outer portions of the opposed end walls, the outer periphery and the internal wall of the vessel and which forms the annular outer chamber, with the open radially inner volume of the toroidal enclosure being closed by axially spaced end caps sealingly engaged with the enclosure and defining the inner portions of the opposed end walls of the vessel to form the first chamber.

In another embodiment, the fluid storage vessel may comprise a preformed enclosure having opposed ends and a peripheral wall defining, respectively, the inner portions of the opposed end walls of the vessel and the internal wall whereby the enclosure forms the first inner chamber of the vessel, said vessel further comprising an annular portion sealingly engaged with the enclosure to form the second annular chamber. The opposed ends of the preformed enclosure may be convex.

In this embodiment, the annular portion advantageously radially inwardly overlaps the peripheral wall of the preformed enclosure and is secured at each end to the respective opposed end of the preformed enclosure. With the annular portion overlapping the preformed enclosure, it is necessary to form the annular portion in at least two parts which are secured together, preferably by welding, around the preformed enclosure.

Advantageously, two parts are formed as substantially identical shells which are welded together on the outer periphery of the vessel along an axially central diametrical plane of the vessel. However, the two shells need not be substantially identical, and one of the shells may comprise a greater part of the outer periphery than the other, or all of the outer periphery, but preferably the two shells are welded together along a diametrical plane.

The term "preformed" as used in "preformed enclosure" herein should be construed merely to mean the enclosure is formed at some stage before the aforementioned annular WO 97/09561 PCT/AU96/00544 -7portion is or end caps are secured to the enclosure.

The preformed enclosure in either of the above two embodiments may be formed in a variety of ways which will be well understood by those skilled in the art. Particularly in the case of said other embodiment, the preformed enclosure is preferably formed as two shells which are secured together, preferably by welding, most preferably as two substantially identical shells which are secured together along a diametrical plane which intersects the centre of the preformed enclosure. While the two shells need not be substantially identical, most preferably the two shells are welded together along a diametrical plane.

In the case of said one embodiment, the toroidal preformed enclosure is advantageously formed by welding or otherwise securing two shell portions, respectively defining the outer portions of the opposed end walls and together (or one only) defining the outer periphery, to opposite ends of a substantially tubular portion which will at least substantially define the internal wall of the vessel. This substantially tubular portion is preferably formed from seamless tubing which may advantageously be flared at its opposite ends to facilitate joining to the shell portions. Each end cap may be secured to a respective one of the shell portions.

The annular portion or end caps of the vessel are most advantageously welded to the preformed enclosure.

Two embodiments of a fuel vessel in accordance with the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a sectional view of a first embodiment of the vessel taken along the axial plane I-I in Figure 2; Figure 2 is a plan view of the first embodiment of the vessel; Figure 3 is a sectional view of a second embodiment of the vessel taken along the axial plane I-I of Figure 4; WO 97/09561 PCT/AU96/00544 -8- Figure 4 is a plan view of the second embodiment of the vessel; Figures 5 and 6 correspond to Figures 1 and 2 but show a variety of modifications to the first embodiment of fuel vessel; and Figure 7 is a partial sectional view on the line II-II of Figure 6.

Referring to Figures 1 and 2. the vessel 10 is formed of steel and comprises a preformed inner enclosure 12 and an annular outer enclosure 14.

Tile preformed enclosure has a cylindrical peripheral wall 16 and opposed convex end walls 18 and 20. The preformed enclosure is formed in two substantially identical halves which are secured together along a diametrical plane which intersects the centre of the vessel by a joggle-butt weld 22. The preformed enclosure 12 may be formed of thicker material or material of a higher grade than that of outer enclosure 14.

The peripheral wall 16 is continuous so as to prevent fluid flow therethrough between the inner enclosure 12 and outer enclosure 14.

The outer enclosure 14 is formed from two substantially identical annular shells 32 and 34 which are welded together at a joggle-butt joint 36 in the axially extending peripheral wall 38 of the vessel 10. The axial opening 40 (see Figure 2) defined by the shells 32 and 34 has a smaller diameter than the diameter of the inner enclosure 12 so that shells 32 and 34 are welded together after they have been disposed over the respective end walls 18 and 20 of the inner enclosure. The axial end portions 42 and 44 of the annular outer enclosure 14 are also convex when viewed on respective sides of the axis of the vessel, and the radially inner edges thereof defining the opening 40 abut the end walls 18 and of the inner enclosure at approximately right angles, for example between 80 and 1000, adjacent where those end walls 18 and 20 merge with the peripheral wall 16. The annular joins are then welded exteriorly at 46 and 48.

The axial lengths of the inner and outer enclosures 12 and 14 are substantially the same so that the opposed end walls of the vessel defined by the wall portions 18 and 42 and WO 97/09561 PCT/AU96/00544 -9and 44, respectively, extend substantially in respective planes.

A valve 50 is shown generally and schematically in the peripheral wall 38 of the vessel and may be in the form of a known multi-valve assembly for use with LPG or other pressurized fuel such as CNG. Alternatively, plural valve openings may be provided.

A non-pressurized fuel port 52 is shown generally and schematically in the end wall of the inner enclosure, and may be of any suitable type for use with petrol or diesel. The port 52 may be offset as shown or may be provided on the axis of the inner enclosure 12.

Alternatively, the valve 50 and port 52 may be swapped with each other to allow pressurized fuel to be stored in the inner enclosure 12 and non-pressurized fuel in the outer enclosure 14, or the same or similar types of valve or port may be provided in both enclosures if the same type of fuel is to be stored. The respective volumes of the inner and outer enclosures 12 and 14 may be varied in manufacture according to the desired storage volume for each.

The inner enclosure can advantageously be formed on a production line for small pressurized gas vessels such as are used for barbeques although, if the inner enclosure is to be used for storing non-pressurized fluid or lightly pressurized fluid, it may not be necessary for the inner enclosure to have convex ends. A major advantage of the vessel 10 is its simplicity of manufacture since the shells 32 and 34 of the outer enclosure can be automatically centralised on the inner enclosure prior to welding. Since the internal wall is integrally formed with the inner enclosure, it may give improved strength and fatigue or pulsation resistance to the vessel as a whole. Furthermore, it will be noted that the weld lines all extend perpendicularly to the longitudinal axis of the vessel which gives considerably greater strength than longitudinal welds.

It will be appreciated that the joggle-butt welds may be replaced by, for example, butt welds using a backing plate.

As will be appreciated by those skilled in the art, many of the features and alternatives described with reference to the fuel vessel 10 are applicable also to the vessel 60 shown WO 97/09561 PCT/AU96/00544 in Figures 3 and 4, and, for example, the valve 50 and port 52 are numbered similarly in Figures 3 and 4 and will not be described further.

The vessel 60 comprises a preformed toroidal shell 62 which defines an annular outer chamber 64 and, with opposed axial end plates 66 and 68, an axially inner substantially cylindrical chamber The toroidal shell 62 is formed of three parts, axially opposed shell portions 72 and 74 and a substantially cylindrical tubular portion 76, welded together. The tubular portion 76 is advantageously formed from seamless steel tubing cut to the desired length and flared in a press at axially opposite ends 78 to facilitate the formation of joggle butt welds with the respective shell portions 72 and 74. The shell portions 72 and 74 are substantially identical to each other and define respective convex outer ends 80 of the outer chamber 64 and respective halves of the peripheral or outer wall 82. However, the shell portion 72 is flared inwardly at its radially outer end 84 so as to facilitate the formation of a joggle butt weld at the axially central diametrical seam 86 of the two shell portions. The internal wall 76 and peripheral wall 82 are conveniently cylindrical but merge with the axially outer ends 80 of the toroidal shell 62 through rounded corners.

The tubular portion 76 may be formed of thicker material or material of a higher grade than that of the shell portions 72 and 74.

As noted above, the inner chamber 70 is formed by welding planar circular end plates 66 and 68 to the axially outer ends 80 of the toroidal shell 62 to define the radially inner axial end portions of the vessel 60. As shown, the fuel vessel 60 is suitable for receiving LPG or other pressurized fuel in the annular outer chamber 64 and non-pressurized fuel, such as petrol, in the inner chamber 70. If it is desired to carry pressurized fuel in the inner chamber 70, the end caps 66 and 68 may require reinforcing, by for example making them slightly convex. Alternatively, any of the aforementioned reinforcing methods may be applied to the end plates 66 and 68.

If both the outer chamber 64 and inner chamber 70 are to carry the same fuel. such as WO 97/09561 PCT/AU96/00544 -11- LPG, a suitable switching device (not shown) may be provided to switch the supply of fuel from the larger, main outer chamber to the smaller reserve or emergency inner chamber.

Referring now to Figures 5 to 7, there is shown a modified fuel vessel 10' having a variety of modifications over the fuel vessel 10 of Figures 1 and 2. Any of these modifications may be used independently in the fuel vessel 10, or for that matter in the fuel vessel 60 of Figures 3 and 4 with appropriate variation. For convenience, the same reference numerals have been used in Figures 5 to 7 as in Figures 1 and 2. Where the referenced part has been modified, a has been added to the reference numeral. Only modified parts will be described.

The axial end wall 44' of the upper shell 34' of the outer enclosure 14' incorporates two modifications.

Firstly, a valve compartment 90 has been welded into an opening 92 in the axial end wall 44' so that the valve components (not shown) for the pressurized fuel in the outer enclosure 14' are substantially recessed within the contour of the shell 34'. The valve compartment has a cover 94 which is secured to the compartment by threaded fasteners 96. A pipe fitting 98 projects outwardly from the compartment to provide a passage for fuel lines and other leads associated with the valve components. The bottom wall 100 of the valve compartment will have one or more openings therethrough (not shown) associated with the valve components.

Secondly, the axial end wall 44' has been modified to include a radially extending groove 102 to accommodate fuel lines and other leads (not shown) associated with the inner enclosure 12' substantially beneath the overall contour of the upper shell 34'. The groove 102 may be readily formed during a pressing operation for the shell 34'.

The inner enclosure 12' has been modified by including a fuel pump 104, shown schematically for injecting the petrol or diesel in the inner enclosure into the engine. To

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WO 97/09561 PCT/AU96/00544 12enhance the convenience of providing the fuel injector 104 in the enclosure 12', and to facilitate access to it in case of service or repair, the axial end wall 20' of the inner enclosure 12' is modified by including an opening 106 in a flattened central portion 108.

The opening 106 is closed by a cover 110 which is secured to the end wall 20' by threaded fasteners 112. A fuel line 114 from the fuel pump 104 is shown extending through the cover 110. One or more other openings (not shown) through the cover 110 will be provided for a fuel inlet line and other leads.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the invention includes all such variations and modifications which fall within its spirit and scope. In particular it will be understood that the invention extends to the methods of making fuel vessels disclosed herein.

Claims (21)

1. A fluid storage vessel for automotive or other use having opposed end walls connected at or adjacent an outer periphery and an annular internal wall extending between the opposed end walls whereby said vessel comprises a first inner chamber defined by inner portions of the opposed end walls of the vessel and the internal wall and a second annular chamber around the first chamber defined by the internal wall and outer portions of the opposed end walls connected at the outer periphery of the vessel, said internal wall preventing fluid flow between the chambers, and wherein each chamber is provided with a respective fluid flow connection to the exterior.

2. A vessel according to Claim 1 wherein the annular internal wall has a circular cross-section.

3. A vessel according to Claim 1 wherein the outer periphery of the vessel is substantially circular.

4. A vessel according to Claim 1 wherein the outer periphery of the vessel is substantially oval.

A vessel according to Claim 1 wherein the annular internal wall is formed of a material having greater strength than material defining exterior surfaces of the outer annular chamber.

6. A vessel according to Claim 1 wherein the outer periphery is defined by an outer wall which extends substantially parallel to the axis of the internal wall and the radially outer portions of the opposed end walls are convex.

7. A vessel according to Claim 1 which is adapted to carry pressurized fluid in the second annular chamber and non-pressurized fluid in the first inner chamber. P:\OPER\PHH\67812-96.RES 29/7/99 -14-

8. A vessel according to claim 1 wherein the second annular chamber comprises two opposed shell portions defining the outer portions of the end walls and the outer periphery, the shell portions being substantially identical and being secured to each other along an axially central diametrical plane of the vessel.

9. A vessel according to claim 1 which comprises a preformed toroidal enclosure which defines the outer portions of the opposed end walls, the outer periphery and the internal wall of the vessel and which forms the annual outer chamber, with the open radially inner volume of the toroidal enclosure being closed by axially spaced end caps sealingly engaged with the enclosure and defining the inner portions of the opposed end walls of the vessel to form the first chamber.

A vessel according to Claim 9 wherein the toroidal preformed enclosure has been formed by welding two shell portions, defining the outer portions of the opposed end walls o 15 and the outer periphery, to opposite ends of a tubular portion which at least substantially defines the internal wall in the vessel. g

11. A vessel according to Claim 10 wherein the tubular portion is formed from seamless tubing.

A vessel according to Claim 10 wherein the tubular portion is flared at its opposite oo*ends.

13. A vessel according to Claim 10 wherein each end cap is secured to a respective one S 25 of the shell portions. a o•

14. A vessel according to Claim 9 wherein each end cap is substantially planar.

A vessel according to Claim 1 which comprises a preformed enclosure having opposed ends and a peripheral wall defining, respectively, inner portions of the opposed end walls of the vessel and the internal wall whereby the enclosure forms the first inner chamber of the P:\OPER\PHH\67812-96.RES 29/7/99 vessel, said vessel further comprising an annular portion sealingly engaged with the enclosure to form the second annular chamber.

16. A vessel according to Claim 15 wherein the opposed ends of the preformed enclosure are convex.

17. A vessel according to Claim 15 wherein the preformed enclosure comprises two shells which are secured together around the peripheral wall.

18. A vessel according to Claim 17 wherein the two shells are substantially identical and are welded together along an axially central diametrical plane of the preformed enclosure.

19. A vessel according to Claim 15 wherein the annular portion radially inwardly overlaps the peripheral wall of the preformed enclosure and is secured at each end to the respective 15 opposed end of the preformed enclosure.

20. A vessel according to claim 15 wherein the annular portion of the vessel is welded to the preformed enclosure and the outer portions of the opposed end walls of the vessel defined •by the annualar portion meet the preformed enclosure at approximately right angles.

21. A fluid storage vessel substantially as herein described with reference to the accompanying drawings. •oo e• 25 DATED this 29th day of July, 1999 DONALD SCOTT ROBINSON By Its Patent Attorneys DAVIES COLLISON CAVE