Fuel-pick-up device

Abstract

A fuel pick-up device comprises a head (11), a float (14) arranged for rising and falling with the level of fuel in a tank and an elongate flexible coiled pick-up duct (13) extending helically between the float (14) and the head (11). An elongate constraint (10) extends downwardly from the head (11) and is arranged to at least partially constrain the float (14) against radial movement. The float (14) comprises an annular body (17) at its lower end which is provided with a fuel inlet (15) connected to a lower end of the duct (13). The float (14) further comprises a buoyant float member (16) at its upper end, the float member having a diameter D1 which is less than the diameter D2 of a void V defined by the helically extending coiled duct (13). In use, when the fuel tank is full, the float member (16) nests inside the void V and enables the fuel inlet (15) to rise closer to the surface of the fuel, reducing the risk of drawing contaminants suspended at lower levels in the tank.

Description

[0001] FUEL-PICK-UP DEVICE

[0002] The present invention relates to a fuel pick-up device for extracting fuel from a tank or similar reservoir, and in particular to a device configured to reduce the ingestion of contaminants.

[0003] In conventional fuel tanks, the fuel is drawn from a point adjacent the bottom of the tank in order to enable the pick-up of fuel even when the level of fuel in the tank is low. However, a disadvantage of this arrangement is that any water and / or contaminants which have accumulated at the bottom of the tank can be drawn up with the fuel and fed to the apparatus which is being supplied with fuel. In most cases, the fuel is supplied to an internal combustion engine, where contaminants can cause engine malfunction or damage.

[0004] WO2010 / 136791 discloses a solution to this problem in the form of a fuel-pick-up device for fitting within a fuel tank. The device comprises an elongate circular-section constraint portion and a float portion. The constraint portion comprises a tubular metal baffle provided with an array of apertures, the float portion being mounted inside constraint for rising and falling with the level of fuel in the tank. A coiled flexible fuel duct extends upwardly from the top of the float portion to a fuel outlet pipe leading from the tank. The float portion comprises a hollow float housing having an upper end which encloses a buoyant float member that is filled with air. The float housing is substantially cylindrical in shape and comprises a perforated wall at its bottom end, which serves as a fuel inlet to the device and which acts to filter fuel to prevent sediment and other matter from being drawn into the device. The float member is substantially cylindrical in cross-section and the float housing comprises a side wall having a plurality of spacer formations which space the outer surface of the float member from the inner surface of the float housing and which act to centralise the float member within the float housing, so that fuel entering the fuel inlet at the bottom of the float housing can flow upwardly inside the housing around the float member and into the coiled flexible fuel pick-up duct. The large cross-sectional area of the flow channel inside the float portion allows high fuel flow rates from the fuel tank which are sufficient to fuel to machinery requiring a large fuel supply, for example.

[0005] In use, the float portion floats keeps the fuel inlet away from the worst of the sediment and contaminants at the bottom of the tank and thus the risk of drawing up sediment or contaminants such as water from the bottom of the tank is avoided. Fuel-pick-up devices of the type disclosed in WO2010 / 136791 have met with considerable commercial success, particularly as a retro-fit to the fuel tanks of vehicles and other machines used in industries where fuel contamination is problematic. This generally involves inserting the elongate tubular constraint of the device through an aperture in the top wall of the fuel tank, such that the constraint extends almost fully towards the bottom of the tank. The device is then secured in-situ by mounting a head portion thereof to the wall of the tank.

[0006] A problem of the fuel-pick-up device disclosed in WO2010 / 136791 is that when a fuel tank is full, the upper end of the float portion abuts the coiled flexible fuel duct at the top of the constraint portion, thereby undesirably holding the fuel inlet to the device substantially below the surface of the fuel in the tank. Accordingly, fuel is not drawn from the surface of the fuel in the tank and thus there is a risk of drawing up contaminants suspended below the surface.

[0007] With the aforementioned problem in mind, we have now devised an improved fuel pickup device.

[0008] In accordance with the present invention, there is provided a fuel pick-up device comprising a head portion, a float portion arranged for rising and falling along an axis with the level of fuel in a tank, an elongate flexible coiled pick-up duct extending helically upwardly from the float towards the head and an elongate constraint portion extending downwardly from the head, the constraint being arranged to at least partially constrain the float against radial movement relative to said axis, wherein the float comprises a lower end portion provided with a fuel inlet connected to a lower end of the coiled pick-up duct and an upper end portion provided with a buoyant float member, the float member having a diameter which is less than the diameter of a void defined by the helically extending coiled pick-up duct, wherein the float member is adapted to project into the void of the helically extending coiled pick-up duct when the tank is at least partially full of fuel.

[0009] In use, when the level of fuel in the tank high, the buoyant float member at the upper end of the float portion nests inside the void defined by the coiled flexible fuel duct at the top of the constraint portion, thereby substantially increasing the distance by which the float portion is able to rise with the level of the fuel in the tank compared with that of the fuel-pick-up device disclosed in WO2010 / 136791. In this manner, the fuel inlet is able to remain adjacent the surface of the fuel in the tank for a larger range of fuel depths, so that fuel is drawn from the surface of the fuel in the tank and thus the risk of drawing up contaminants suspended below the surface is substantially reduced.

[0010] The diameter of the float member is thus configured so that it can nest in the void of the helically extending coiled pick-up duct when the tank is full or partially fully, thereby enabling the fuel inlet to rise closer to the surface of the fuel, reducing the risk of drawing contaminants suspended at lower levels in the tank.

[0011] The lower end portion of the float may have cross-sectional area which is greater than the cross-sectional area of the upper end portion of the float. In this manner, the area of the fuel inlet on the lower end portion can be maximised to allow for high fuel flow rates.

[0012] The lower end portion of the float may comprise an annular body having a bottom wall provided with a plurality of openings which define said inlet.

[0013] In order to maximise the area of the inlet, the annular body may have a diameter greater than the diameter of the turns of the helically extending coiled pick-up duct.

[0014] The float member may be detachable from the float, for example so that a float member of a desired length can be attached or so that a float members having a desired levels of buoyancy can be attached.

[0015] The lower end portion of the float may comprise an abutment formation which depends from a central recess inside the annular body. In use, the abutment formation prevents the inlet from abutting the bottom of the tank when the level of fuel in the tank is low.

[0016] The abutment formation may be extendable, for example by connecting a plurality of abutment members end-to-end.

[0017] The abutment formation may be detachable, for example so that an abutment member of the formation having a desired axial length can be selectively attached to the float. The abutment member may engage a bottom end of the float member through an aperture in a recessed central wall of the annular body, for example by means of a screw thread.

[0018] The axial length of the float member may exceed the minimum axial length of the void defined by the helically extending coiled pick-up duct when the level of fuel in the tank is high, the upper end of the float member being adapted to abut a portion of the head. In this manner the float member acts as an abutment formation to control the uppermost position of the inlet when the level of fuel in the tank is high.

[0019] Embodiments of the present invention will now be described by way of examples only and with reference to the accompanying drawings, in which:

[0020] Figure 1 is a longitudinal sectional view through an embodiment of fuel-pick-up device in accordance with the present invention;

[0021] Figure 2 is a perspective view from one side and above of a float of the fuel-pick-up device of Figure 1 ;

[0022] Figure 3 is an exploded view of the float Figure 2;

[0023] Figure 4 is a longitudinal sectional view through an alternative embodiment of fuel- pick-up device in accordance with the present invention;

[0024] Figure 5 is a perspective view from one side and above of a float of the fuel-pick-up device of Figure 4; and

[0025] Figure 6 is an exploded view of the float Figure 5.

[0026] Referring now to Figures 1 to 3 of the drawings, there is shown an embodiment of fuel- pick-up device in accordance with the present invention, the device comprising an elongate circular-section constraint 10 which is closed at its first end by a flanged head 11. The constraint 10 comprises a tubular side wall provided with a plurality of apertures (not shown) to permit fuel access inside the constraint 10. The head 11 is arranged for securing around its periphery to a circular aperture formed in the top wall of a fuel tank (not shown).

[0027] A feed pipe 12 extends through the head 11 as shown in Figure 1 , the lower end of the pipe 12 being connected to an elongate helical coiled flexible pick-up duct 13 of plastics material.

[0028] A float 14 is arranged for freely rising and falling along an axis A-A with the level of fuel in the tank, the constraint 10 being arranged to at least partially constrain the float 14 against radial movement relative to the axis A-A. The float 14 comprises a lower end portion provided with a fuel inlet 15 connected to a lower end of the coiled pick-up duct 13 and an upper end portion provided with a buoyant float member 16. The float 16 has a diameter D1 which is less than the diameter D2 of a void defined by the helically extending coiled pick-up duct 13.

[0029] The lower end portion of the float 14 comprises an annular body 17 having a bottom wall provided with a plurality of openings which define the inlet 15 of the device. The annular body 17 has a cross-sectional area which is greater than the cross-sectional area of the float member 16. The annular body 17 also has a diameter greater than the diameter of the turns of the helically extending coiled pick-up duct 13. The inlet 15 of the device leads into an annular chamber 18 inside the annular body 17. The lower end of the flexible duct 13 is connected to an upwardly-inclined tubular connector 19 extending tangentially from a top wall of the annular chamber 18.

[0030] The lower end portion of the float 14 comprises a tubular abutment member 20 which depends from a central recess 21 formed inside the annular body 17. An externally screw threaded formation 22 depends from the bottom end of the float member 16 through an aperture 25 formed in a recessed central wall 23 of the annular body 17. The tubular abutment member 20 threadably engages the formation 22, thereby clamping both the float member 16 and tubular abutment member 20 in-situ on the float body 17.

[0031] In use, the device functions in the same manner as the device of WO2010 / 136791. However, when the fuel tank is full of fuel, the buoyant float member 16 at the upper end of the float 14 nests inside a cylindrical void V defined by the coiled flexible fuel duct 13 at the top of the constraint 10, thereby substantially increasing the distance by which the float 14 is able to rise with the level of the fuel in the tank compared with that of the fuel-pick-up device of WO2010 / 136791. In this manner, the fuel inlet 15 remains adjacent the surface of the fuel in the tank for a larger range of fuel depths, so that fuel is drawn from the surface of the fuel in the tank and thus the risk of drawing up contaminants suspended below the surface is substantially reduced.

[0032] When the level of fuel is low, the abutment member 20 prevents the inlet from abutting the bottom of the tank. The abutment member 20 is detachable from the screw threaded formation 22 at the bottom end of the float member 16, so that an abutment member having a desired axial length can be selectively attached to the float 14. In another embodiment, the abutment member 20 may be extendable, for example by connecting a plurality of abutment members end-to-end.

[0033] The axial length of the float member 16 exceeds the minimum axial length of the void V defined by the helically extending coiled pick-up duct 13 when the level of fuel in the tank is high, whereupon the upper end of the float member 16 abuts a depending projection 24 on the head 11. In this manner the float member 16 advantageously acts as an abutment formation to control the uppermost position of the inlet 15 when the level of fuel in the tank is high.

[0034] Referring now to Figures 4 to 6 of the drawings, there is shown an alternative embodiment of fuel-pick-up device which is similar in construction to the fuel-pick-up device of Figures 1 to 3 and like parts are given like reference numerals. The float 14 of the fuel-pick-up device is simpler in construction than that of Figures 1 to 3 and comprises 6 component parts which can moulded relatively easily using conventional techniques.

[0035] The float 14 comprises a moulded upper end portion 26 having a lower tubular body 27 provided with a fuel outlet port 28 on its peripheral top wall. A separately moulded spigot 28 is provided for engaging with the port 28 to facilitate connection to the lower end of the elongate helical coiled flexible pick-up duct 13. A separately moulded O- shaped retainer 30 is provided for engaging with a formation on the peripheral top wall of the body 27, the retainer 30 serving to constrain the lower end of the elongate helical coiled flexible pick-up duct 13 adjacent the inlet 28. In this embodiment, the float member 16 of Figures 1 to 3 is replaced by a hollow float projection 31 which extends upwardly from the centre of the peripheral top wall of the tubular body 27 of the upper end portion. The projection 31 has a closed conical upper end and a lower end which opens inside the body 27 to facilitate moulding. A separate circular disc 32 is provided for ultrasonically welding or otherwise attaching across the open lower end of the hollow float projection 31 , so as to form a primary sealed float chamber 39.

[0036] The float 14 further comprises a moulded lower end portion 33 having a tubular central portion 34. The upper end of the tubular central portion 34 is closed and its lower end is turned radially outwardly to define an annular bottom wall 35 provided with a plurality of openings which define the inlet 15 of the device. A plurality of clips 40 extend upwardly from the outer edge of an annular bottom wall 35 to snap-engage with formations 41 on the lower edge of the tubular body 27. Once the moulded upper and lower end portions 26, 33 are assembled, the inlet 15 of the device leads into an annular chamber 38 inside the float 14, from which fuel is drawn via the tangentially- directed fuel outlet port 28 on the peripheral top wall of the tubular body 27.

[0037] A separate dish-shaped bottom wall member 36 is provided for ultrasonically welding or otherwise attaching across the open lower end of the tubular central portion 34, so as to form a secondary sealed float chamber 37. This secondary float chamber 37 acts to increase the buoyancy of the float 14 to compensate for a reduction in size of the primary float chamber 39 as a result of its moulded construction. It will be appreciated that the degree of buoyancy of the secondary float chamber 37 can be increased by fitting a dish-shaped bottom wall member 36 having a less dished shape and vice- versa. One or more abutment members (not shown) may depend from the central recess formed inside dish-shaped bottom wall member 36. An abutment member may be weighted to serve the purpose of making the float sit lower in the fuel without the need to modify the buoyancy of the float itself. It may also help stabilise the float in certain dynamic applications.

[0038] In use, the device functions in the same manner as the device of Figures 1 to 3. The nesting arrangement of primary float chamber 39 inside the helically extending coiled duct enables the fuel inlet to rise closer to the surface of the fuel, reducing the risk of drawing contaminants suspended at lower levels in the tank.

[0039] A fuel-pick-up device in accordance with the present invention comprises a head, a float arranged for rising and falling with the level of fuel in a tank and an elongate flexible coiled pick-up duct extending helically between the float and the head. An elongate constraint extends downwardly from the head and is arranged to at least partially constrain the float against radial movement. The float comprises an annular body at its lower end which is provided with a fuel inlet connected to a lower end of the duct. The float further comprises a buoyant float member at its upper end, the float member having a diameter which is less than the diameter of a void defined by the helically extending coiled duct. In use, when the fuel tank is full, the float member nests inside the void, thereby substantially increasing the distance by which the float is able to rise with the level of the fuel in the tank compared with that of known devices. The risk of picking up contaminants from the fuel below the surface is thus substantially reduced.

[0040] Another advantage of a fuel-pick-up device in accordance with the present invention is that it comprises a design which can easily be modified for various volumetric fuel flow rates.

[0041] Another advantage of a fuel-pick-up device in accordance with the present invention is that it comprises a design which enables different lengths of float members 16 to be fitted to the float 15 for differing levels of buoyancy.

[0042] Another advantage of a fuel-pick-up device in accordance with the present invention is that it comprises a design which is beneficial for shallow tanks where the overall length of the device is restricted.

[0043] Another advantage of a fuel-pick-up device in accordance with the present invention is that it comprises a design which gives a lower fluid differential pressure drop across the float when compared to fuel-pick-up devices of the type disclosed in WO2010 / 136791.

Claims

CLAIMSA fuel pick-up device comprising a head portion, a float portion arranged for rising and falling along an axis with the level of fuel in a tank, an elongate flexible coiled pick-up duct extending helically upwardly from the float towards the head and an elongate constraint portion extending downwardly from the head, the constraint being arranged to at least partially constrain the float against radial movement relative to said axis, wherein the float comprises a lower end portion provided with a fuel inlet connected to a lower end of the coiled pick-up duct and an upper end portion provided with a buoyant float member, the float member having a diameter which is less than the diameter of a void defined by the helically extending coiled pick-up duct, wherein the float member is adapted to project into the void of the helically extending coiled pick-up duct when the tank is at least partially full of fuel.

1. A fuel pick-up device as claimed in claim 1 , in which the lower end portion of the float has a cross-sectional area which is greater than the cross-sectional area of the upper end portion of the float.

2. A fuel pick-up device as claimed in claim 1 or claim 2, in which the lower end portion of the float comprises an annular body having a bottom wall provided with a plurality of openings which define said inlet.

3. A fuel pick-up device as claimed in claim 3, in which the annular body has a diameter greater than the diameter of the turns of the helically extending coiled pick-up duct.

4. A fuel pick-up device as claimed in claim 3 or claim 4, in which the lower end portion of the float comprises an abutment formation which depends from a central recess inside the annular body and is configured to prevent the fuel inlet from contacting the bottom wall of the tank.

5. A fuel pick-up device as claimed in claim 3, in which the abutment formation is extendable.

6. A fuel pick-up device as claimed in claim 3, in which the abutment formation is detachable.

7. A fuel pick-up device as claimed in claim 7, in which the abutment member engages a bottom end of the float member through an aperture in a recessed central wall of the annular body.

8. A fuel pick-up device as claimed in claim 8, in which the abutment member threadably engages the bottom end of the float member through the aperture.

9. A fuel pick-up device as claimed in any preceding claim, in which the axial length of the float member exceeds the minimum axial length of the void defined by the helically extending coiled pick-up duct when the level of fuel in the tank is high, the upper end of the float member being adapted to abut a portion of the head.

10. A fuel pick-up device as claimed in any preceding claim, in which the float member is detachable from the float.

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