GB2424870A

GB2424870A - Anti siphoning fuel tank inlet assembly

Info

Publication number: GB2424870A
Application number: GB0506854A
Authority: GB
Inventors: Richard Nigel Fowler
Original assignee: TruckProtect Ltd
Current assignee: TruckProtect Ltd
Priority date: 2005-04-04
Filing date: 2005-04-04
Publication date: 2006-10-11
Also published as: US20080308182A1; ZA200709134B; GB0506854D0; CA2648497A1; CN101155708A; CN101155708B

Abstract

A fuel tank inlet assembly (1) for fitting to an inlet aperture of a fuel tank, the inlet assembly comprising: an inlet (2) for receipt of fuel and an outlet (3) for egress of fuel into the fuel tank, a valve (4) provided at the outlet that, in use, allows egress of fuel into the fuel tank but resists ingress of fuel from the fuel tank, and a barrier assembly (7) provided between the inlet and the outlet arranged so that there is no straight line path from the inlet to the valve in the presence of the barrier assembly, wherein the inlet and outlet are arranged so that, in the absence of the barrier assembly therebetween, there is at least one straight line path between the inlet and the valve. The barrier assembly may form a tortuous path, an s-shaped or serpentine path between the inlet and the valve. The barrier assembly may include a series of bars or plates 7a-7d or hollow, perforated spherical bodies (27a-27c, fig. 2). In an alternative embodiment the barrier assembly may include a helical member (17, fig. 3). The barrier assembly prevents siphoning or skimming.

Description

Fuel tank inlet assembly The present invention relates to fuel tank inlet

assemblies, particularly but not exclusively those that may be used to inhibit the unauthorised removal of liquid fuel (such as gasoline and diesel) from the fuel tanks of vehicles, such as lorries and cars-.

Such fuel tank inlet assemblies often take the form of a tube that is inserted into the filling neck of a tank. The tube may be perforated, for example, in order to allow passage of fuel therethrough, the perforations being of such a size so as to inhibit the introduction of a siphoning tube into the main body of the fuel tank (for example, see FR2820372, GB739386, US5025946) . Alternatively or additionally, the tube may be provided with an aperture (typically at or near one end) that is provided with a liquid-permeable barrier (such as a gauze) that inhibits passage of a siphoning tube into the main body of the fuel tank (for example, see FR2820372, w02005/002897) . This does not prevent a fuel thief from inserting a siphoning tube into the tube of the fuel tank inlet assembly and removing as much fuel from the tank as this will allow. Such removal of fuel is known as "skimming" and can result in a substantial loss of fuel that cannot be readily detected by the owner or user of the vehicle.

This problem has been addressed by the fuel tank inlet assemblies of GB2406333 which is provided with a float valve so that when the level of fuel is above that of the float valve, the valve floats and engages with a valve seat, preventing fuel flow back into the device. This arrangement therefore only allows the thief to remove the volume of fuel that is in the cavity formed by the inlet assemblies.

GB2406333 also describes the use of a liquid-permeable grill positioned slightly above the valve seat to prevent a siphon tube being used to force the valve from its valve seat. Such an arrangement is however vulnerable to attack and it is possible to penetrate the grill with a straight, relatively rigid implement such as a knitting needle, or to insert a rigid implement through the holes in the grill, thereby moving the valve away from the valve seat and allowing large amounts of fuel to be removed from the fuel tank.

Furthermore, the inlet assembly of GB2406333 also suffers from the problem that when the level of fuel is above the float then entry of fuel into the fuel tank is undesirably inhibited.

The device of the present invention addresses one or more of the problems described above.

In accordance with a first aspect of the present invention there is provided a fuel tank inlet assembly for fitting to an inlet aperture of a fuel tank, the inlet assembly comprising: an inlet for receipt of fuel and an outlet for egress of fuel into the fuel tank, a valve provided at the outlet that, in use, allows egress of fuel into the fuel tank but resists ingress of fuel from the fuel tank, and a barrier assembly provided between the inlet and the outlet arranged so that there is no straight line path from the inlet to the valve in the presence of the barrier assembly, wherein the inlet and outlet are arranged so that, in the absence of the barrier assembly therebetween, there is at least one straight line path between the inlet and the valve.

This provides an improved fuel tank inlet assembly that provides greater resistance against unwanted tampering.

The barrier assembly may form a tortuous path between the inlet and the valve. Such a path shape makes it more difficult to tamper with the valve.

The barrier assembly may form an S-shaped or serpentine path between the inlet and the valve. Such a path shape makes it more difficult to tamper with the valve.

It is preferred that the inlet assembly comprises a conduit, the barrier assembly being located within the conduit. It is further preferred that the inlet and outlet are provided near or at opposite ends of the conduit. It is further preferred that the conduit is substantially straight. Such a conduit is easy to manufacture.

The barrier assembly may comprise two fuel-permeable plates, mutually spaced in a direction defined from the inlet to the outlet, each plate projecting fully across the conduit. More than two fuel-permeable plates may be arranged in this way.

Additionally or alternatively, the barrier assembly may comprise two plates, mutually spaced in a direction defined from the inlet to the outlet, each plate projecting partway across the conduit. It is preferred that at least one of the plates projects at least halfway across the conduit. At least one of the plates may be provided with apertures for fuel of flow therethrough. It is further preferred that the plane of at least one of the plates is non-orthogonal to the longitudinal axis of the portion of the conduit in the region of the plate. This potentially reduces backflow.

Additionally or alternatively, the barrier assembly may comprise a helical member. Such a helical member may be mounted in the conduit (if present), the longitudinal axis of the helical member being co-axial with the longitudinal axis of the conduit in the region of the helical member.

This allows fuel to flow around the helix from the inlet to the outlet, but inhibits unwanted access to the valve from the inlet.

Additionally or alternatively, the barrier assembly may comprise a plurality of perforated hollow bodies. Such bodies would be permeable to fuel, but would inhibit access to the valve from the inlet. The hollow bodies may be balls which are preferably substantially spherical. The inlet assembly may comprise comprising containment means for inhibiting movement of the hollow bodies within the assembly. The containment means may comprise an apertured chamber. This may be provided by projections above and below the perforated bodies that provide apertures that are smaller than the smallest external overall dimensions of the perforated bodies so that the bodies cannot pass through the apertures.

Additionally or alternatively, the barrier assembly may comprise a plurality of bars. It is preferred that the bars are used in conjunction with other barrier assembly components (such as plates) and are located so as to *inhibit access from the inlet to the other barrier assembly components.

The assembly may comprise a fuel vent comprising a vent door and a vent seat, the vent door being movable from a closed position in which the vent seat and vent door co-operate to resist ingress of fuel into the assembly to an open position under the influence of fuel being delivered via the inlet into the inlet assembly. This allows more fuel to flow into the fuel tank than if the vent was absent, thereby reducing the chance of backflow occurring. It is preferred that the vent door is biased into the closed position (for example, by a spring) The assembly may be provided with means for resisting withdrawal of the inlet tank assembly once mounted in the inlet aperture of a fuel tank. This helps prevent unwanted removal of fuel from the tank. The means for resisting withdrawal may comprise a plurality of barbs. These may be provided on an external surface of the assembly, in particular an external surface of a conduit (if present) The valve may be a non-return valve.

The valve may be a float valve comprising a valve portion movable with respect to a valve seat from a first position in which, in use, fuel is permitted to flow out of the inlet assembly, and a second position in which the valve portion engages with the valve seat to inhibit flow into the inlet assembly. Float valves provide a cheap and reliable valve mechanism.

The valve portion may comprise a float. The float may be trapped in an apertured float chamber. This prevents loss of the float. Instead of being located in a float chamber the float may be tethered. This is an alternative way of inhibiting loss of the float.

The valve portion (i.e. that feature which engages with the valve seat to inhibit return flow into the inlet assembly) may comprise a flap, wherein the flap is associated with a float. The flap and float may be integrated with one another. This may be achieved by incorporating the float into (or bonding the float onto) one face of the flap.

Alternatively, the float may be attached to the flap by a linking member, such as a chain or cord. This presents a simple but effective valve mechanism.

The valve may alternatively be operated by an actuator. The actuator may operate the valve in response to a measured parameter or in accordance with an algorithm.

In accordance with a second aspect of the present invention there is provided a fuel tank inlet assembly for fitting to an inlet aperture of a fuel tank, the inlet assembly comprising: an inlet for receipt of fuel and an outlet for egress of fuel into the fuel tank, a valve provided at the outlet that, in use, allows egress of fuel into the fuel tank but resists ingress of fuel from the fuel tank, and a barrier assembly provided between the inlet and the outlet arranged so that there is a tortuous path between the inlet and the valve, wherein the inlet and outlet are arranged so that, in the absence of the barrier assembly therebetween, S there is at least one straight line path between the inlet and the valve.

The fuel tank inlet assembly in accordance with the second aspect of the present invention may comprise any of those features described above with respect to the fuel tank inlet assembly of the first aspect of the present invention.

In accordance with a third aspect of the present invention there is provided a fuel tank inlet assembly for fitting to an inlet aperture of a fuel tank, the inlet assembly comprising: a substantially cylindrical conduit disposed between an inlet for receipt of fuel and an outlet for egress of fuel into the fuel tank, a valve provided at the outlet that, in use, allows egress of fuel into the fuel tank but resists ingress of fuel from the fuel tank, and a barrier assembly disposed within the conduit and arranged so that there is no straight line path from the inlet to the valve in the presence of the barrier assembly, wherein the inlet and outlet are arranged so that, in the absence of the barrier assembly, there is at least one straight line path between the inlet and the valve.

The present invention will be described by way of example only with reference to the following figures of which: Figure 1 is a cross-section through a first embodiment of an inlet assembly in accordance with the present invention, the barrier assembly resisting access to the float valve comprising a plurality of mutually-spaced sheets, Figure la is a perspective view of the barrier assembly used in the inlet assembly of Figure 1 Figure 2 is a cross-section through a portion of a second embodiment of an inlet assembly in accordance with the present invention, the barrier assembly resisting access to the float valve comprising a plurality of perforated hollow spheres, Figure 3 is a perspective, exploded view of a portion of a third embodiment of an inlet assembly in accordance with the present invention, the barrier assembly resisting access to the float valve comprising a helical barrier, Figure 4 is a cross-section through a portion of a fourth embodiment of an inlet assembly in accordance with the present invention, the barrier assembly resisting access to the float valve comprising a mutually-spaced slotted plate and perforated plate, Figure 5 is a plan view of the slotted plate used in the inlet assembly of the fourth embodiment of the present invention, and Figure 6 is a plan view of the slotted plate used in the inlet assembly of the fourth embodiment of the present invention.

Figure 1 shows a cross-section through a first embodiment of a fuel tank inlet assembly in accordance with the present invention. Briefly, the inlet assembly shown generally by reference numeral 1 comprises an inlet 2 for the receipt of fluid and an outlet 3 for egress of fluid into the fuel tank, a valve 4 provided at the outlet 3 that, in use, allows egress of fluid into the fuel tank but resists ingress of fluid from the fuel tank, and a barrier assembly shown generally by reference numeral 7 provided between the inlet 2 and the outlet 3 arranged so that there is no straight line path from the inlet 2 to the valve 4 in the presence of the barrier assembly 7, wherein the inlet 2 and outlet 3 are arranged so that, in the absence of the barrier assembly 7 therebetween, there is at least one straight line path between the inlet 2 and the valve 4. The assembly 1 comprises a collar portion 9 that is arranged to receive a filler cap 13. The collar portion 9 is provided with female portion of a bayonet fitting (not shown) to engage with the corresponding male portions 14 of a bayonet fitting of the filler cap 13 so that the filler cap 13 can provide an effective seal to the assembly 1 when mounted in a fuel tank. The filler cap 13 may be provided with a lock (not shown) to resist unauthorised removal. The collar portion 9 is attached by means of welding and bolts to a generally cylindrical conduit 15 in the form of a steel tube. The collar portion 9 is manufactured by machining a metal block to the desired shape.

In use, the assembly 1 is mounted onto the filler neck of a fuel tank, typically a fuel tank of a motor vehicle such as a lorry. The end of the cylindrical filler neck (not shown) is received in the annular groove 10 formed in collar portion 9 and the conduit 15 extends into the filler neck.

The assembly 1 is secured using known methods such as adhesives between the collar portion 9 and the filler neck or by screws or bolts that either extend through the collar portion 9 into the filler neck or through the filler neck and into the collar portion 9. Such bolts or screws are typically circumferentially arranged around the collar portion 9.

The valve 4 is a float valve that comprises a float 4b adhered to a flap 4a, the flap being attached by a hinge 5 to conduit 15.

The barrier assembly 7 comprises four plates 7a, 7b, 7c, 7d each having an arcuate edge that is attached to the interior of the cylindrical conduit 15. Each plate projects more than half way across the conduit as shown in Figure la. This provides a flow path for fuel from the inlet 2 to the outlet 3 but inhibits unauthorised tampering with the assembly because there is no straight line path between the inlet 2 and the valve 4 located at the outlet 3. Such a straight line path would more easily allow insertion of a narrow, relatively rigid rod or like instrument to access the valve 4 from the inlet 2 and allow the valve 4 to be damaged or over-ridden. The plates 7a-7d are each angled downwards in order to reduce backflow. The plates may be provided with apertures therethrough to assist in fluid flow and reduce backflow, although such apertures would be arranged so that there is no straight line path between the inlet 2 and the valve 4. The plates 7a-7d are cut from metal sheet, for example, using laser cutting techniques.

The operation of the mounted assembly 1 during the fuelling process is now described with reference to Figure 1. The filler cap 13 is depressed in relation to collar portion 9 and rotated relative to the collar portion 9 in order to remove the filler cap 13. A fuel nozzle of a fuel hose (not shown) is inserted into inlet 2 and fuel is dispensed into the fuel tank via assembly 1. The fuel travels through the portion of the conduit 15 associated with the plates 7a-7d, the fuel travelling through the tortuous path formed by the plates. The fuel pressure causes valve 4 at the outlet 3 to open, the flap 4a hinging open to allow fuel into the fuel tank. Stay 6 ensures that the flap cannot rotate about the hinge 5 by more than 90 degrees. A rotation of more than 90 degrees could lead to the valve 4 not being able to close when fuelling stops. Once fuelling stops, assuming that the level of fuel is above the valve 4, then the float 4b urges the flap 4a into sealing engagement with the valve seat (not shown) . The seal resists ingress of fuel into the assembly from the fuel tank. The float 4b is made of plastic but may be made of any buoyant material.

The assembly 1 is further provided with a fuel vent 12 comprising a comprising a vent door 12a and a vent seat (the vent seat being formed around the periphery of aperture 12b), the vent door l2a being movable from a closed position in which the vent seat and vent door l2a co-operate to resist ingress of fuel into the assembly 1 to an open position under the influence of fuel being delivered via the inlet 2 into the inlet assembly 1. The vent door l2a is biased into the closed position using a spring 12c so that when fuelling is not taking place the door 12 is in the closed position. Such an arrangement reduces backflow by the door opening during fuelling, while resisting unwanted ingress of fuel into the assembly 1.

The assembly is further provided with vapour vents (one of which is labelled 11) . Vapour is pushed out of the apertures 11 when filling the tank so as to prevent a pressure build- up that may inhibit filling of the tank with fuel.

The assembly is further provided with rubber barbs 8a and 8b that help resist unwanted removal of the assembly once it has been fitted to a fuel tank. The barbs in the fitted assembly will be generally pointing upwards from their points of attachment with the conduit 15 and will deform as shown schematically by the dotted lines in Figure 1, thus resisting removal of the device. The barbs 8a, 8b may be sprung metal instead of rubber.

The valve 4 may be replaced with an alternative arrangement.

For example, the float 4b may not be integrated with the flap 4a, but rather connected to the flap 4a by a cord or chain. The float 4b may then, in use, be located external to,or within the conduit 15.

The barrier assembly 7 may further comprise a series or bars (not shown) positioned above the plates 7a-7d, the bars being arranged in a row and extending across the inside of the conduit so as to inhibit access to the plates 7a-7d from inlet 2. Such an arrangement inhibits someone from trying to damage the plates 7a-7d with an implement such as a metal bar.

The collar portion 9 and the conduit 15 (and possibly other components) may be made by injection moulding, rather than being made from metal.

Figures 2, 3 and 4 show alternative barrier assemblies that may be used in the fuel tank inlet assembly of the present invention. Those slcilled in the art will realise that such barrier assemblies are not mutually exclusive and may be used together in one fuel tank inlet assembly.

Figure 2 shows a portion of a fuel tank inlet assembly shown generally by the numeral 41 in accordance with the present invention wherein the barrier assembly 27 comprises several hollow, perforated spherical bodies 27a, 27b, 27c located within a conduit 15, the bodies being contained within an apertured chamber 31 formed by annular projections 28a, 28b, the apertures 29, 30 being of such a size as to prevent the bodies from leaving the chamber. All other features indicated by numeral are as described with reference to figure 1. The perforations in the hollow bodies allow fuel to pass from the inlet 2 to the outlet 3, while there is no straight line path from the inlet 2 to the valve 4.

Figure 3 shows a portion of a fuel tank inlet assembly shown generally by the numeral 51 in accordance with the present invention wherein the barrier assembly comprises a helical member 17 located within a conduit 15. All other features indicated by reference numerals are as described with reference to figure 1. The helical member is mounted snugly within the conduit so that there is no significant free space between the outer edge 17a of the helix and the inner wall of the conduit 15. The helical member 17 allows fuel to pass from the inlet 2 to the outlet 3, while there is no straight line path *from the inlet 2 to the valve 4.

Figure 4 shows a portion of a fuel tank inlet assembly shown generally by the numeral 61 in accordance with the present invention wherein the barrier assembly 37 comprises a first baffle 37a and a second baffle 37b spaced along the length of the conduit 15. All other features indicated by reference numerals are as described with reference to figure 1. Each baffle 37a, 37b is circular in cross-section, having a circular edge that engages with the cylindrical inner surface of the conduit 15. Baffle 37a is shown in Figure 6 and comprises a series of cylindrical apertures therethrough (exemplified by the reference numeral 38) to allow passage of fuel. Baffle 37b is shown in Figure 5 and comprises a series of elongated slots therethrough (exemplified by the reference numeral 39) to allow passage of fuel. This arrangement of baffles 37a, 37b allows fuel to pass from the inlet 2 to the outlet 3, while there is no straight line path from the inlet 2 to the valve 4.

Claims

Claims 1. A fuel tank inlet assembly for fitting to an inlet aperture of a

fuel tank, the inlet assembly comprising: an inlet for receipt of fuel and an outlet for egress of fuel into the fuel tank, a valve provided at the outlet that, in use, allows egress of fuel into the fuel tank but resists ingress of fuel from the fuel tank, and a barrier assembly provided between the inlet and the outlet arranged so that there is no straight line path from the inlet to the valve in the presence of the barrier assembly, wherein the inlet and outlet are arranged so that, in the absence of the barrier assembly therebetween, there is at least one straight line path between the inlet and the valve.
2. A fuel tank inlet assembly according to claim 1 wherein the barrier assembly forms a tortuous path between the inlet and the valve.
3. A fuel tank inlet assembly according to claim 1 or claim 2 wherein the barrier assembly forms an S-shaped or serpentine path between the inlet and the valve.
4. A fuel tank inlet assembly according to any preceding claim comprising a conduit, the barrier assembly being located within the conduit.
5. A fuel tank inlet assembly according to claim 4 wherein the inlet and outlet are provided near or at opposite ends of the conduit.
6. A fuel tank inlet according to claim 4 or 6 wherein the conduit is substantially straight.
7. A fuel tank inlet assembly according to any one of claims 4 to 6 wherein the barrier assembly comprises two plates, mutually spaced in a direction defined from the inlet to the outlet, each plate projecting fully across the conduit.
8. A fuel tank inlet assembly according to any one of claims 4 to 6 wherein the barrier assembly comprises two plates, mutually spaced in a direction defined from the inlet to the outlet, each plate projecting partway across the conduit.
9. A fuel tank inlet assembly according to claim 7 wherein at least one of the plates projects at least halfway across the conduit.
10. A fuel tank inlet assembly according to any one of claims 7 to 9 wherein at least one of the plates is provided with apertures for fuel to flow therethrough.
11. A fuel tank inlet assembly according to any one of claims 7 to 10 wherein at the plane of at least one of the plates is non-orthogonal to the longitudinal axis of the portion of the conduit in the region of the plate.
12. A fuel tank inlet assembly according to any preceding claim wherein the barrier assembly comprises a helical member.
13. A fuel tank inlet assembly according to any preceding claim wherein the barrier assembly comprises a plurality of perforated hollow bodies.
14. A fuel tank inlet assembly according to claim 13 wherein the hollow bodies are substantially spherical.
15. A fuel tank inlet assembly according to claim 13 or 14 further comprising containment means for inhibiting movement of the hollow bodies within the assembly.
16. A fuel tank inlet assembly according to any one preceding claim further comprising a fuel vent comprising a vent door and a vent seat, the vent door being movable from a closed position in which the vent seat and vent door co- operate to resist ingress of fuel into the assembly to an open position under the influence of fuel being delivered via the inlet into the inlet assembly.
17. A fuel tank inlet assembly according to claim 16 wherein the vent door is biased into the closed position.
18. A fuel tank inlet assembly according to any one preceding claim further provided with means for resisting withdrawal of the inlet tank assembly once mounted in the inlet aperture of a fuel tank.
19. A fuel tank inlet assembly according to claim 18 wherein the means for resisting withdrawal comprises a plurality of barbs.
20. A fuel tank assembly according to any preceding claim wherein the valve comprises a valve portion movable with respect to a valve seat from a first position in which, in use, fuel is permitted to flow out of the inlet assembly, and a second position in which the valve portion engages with the valve seat to inhibit flow into the inlet assembly.
21. A fuel tank inlet assembly according to claim 20 wherein the valve portion comprises a float.
22. A fuel tank inlet assembly according to claim 21 wherein the float is trapped in an apertured float chamber.
23. A fuel tank inlet assembly according to claim 21 wherein the float is tethered.
24. A fuel tank inlet assembly according to any one of claim wherein the valve portion comprises a flap wherein the flap is associated with a float.
25. A fuel tank inlet assembly according to claim 24 wherein the flap and float are integrated with one another.
26. A fuel tank inlet assembly according to claim 24 wherein the float is attached to the flap by a linking member.
27. A fuel tank inlet assembly according to any preceding claim wherein the barrier assembly comprises a plurality of bars.
28. A fuel tank inlet assembly according to claim 27 further comprising other barrier assembly components, the bars being located so as to inhibit access from the inlet to the other barrier assembly components.