Patent Description:
In conventional fuel tanks, the fuel in the tank is drawn from a pick-up point adjacent the bottom of the tank, so as 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 or other denser contaminant matter which has accumulated at the bottom of the tank can be drawn up with the fuel from the tank. In order to overcome this problem, the pick-up point is always some distance above the bottom the tank so that water and other contaminant matter is not drawn out from the tank. Over time, the level of the matter in the bottom of the tank will build up and thus it is necessary to regularly clean fuel tanks to alleviate the risk that the level of the matter will extend above the pick-up point. It will be appreciated that it is difficult and dangerous to clean fuel tanks. Furthermore, the fuel tank will have to be decommissioned during cleaning and this is both costly and inconvenient.

It is well known to filter fuel but a disadvantage of this is that the filter can become clogged with matter over time. Furthermore, filters are unable to remove water from the fuel.

Devices for separating water from fuel are well known. <CIT> discloses one such device having an inlet for connecting to a fuel line extending from a fuel tank. The device comprises a cyclonic separator which creates a cyclonic flow of the fuel entering its separation chamber, whereby the fuel spirals downwardly around the chamber towards its lower end. As the fuel swirls inside the chamber, any denser water in the rotating airflow moves radially outward against the outside wall of the chamber, moving then to the bottom of the chamber where it is collected. The separated fuel then leaves the chamber free of water.

<CIT> discloses a method and apparatus for filtration of fuel for use by a vehicle. The apparatus comprises a cyclone chamber that processes fuel passing in through an inlet. The apparatus further comprises a receptacle that receives particulate material that is filtered out of the fuel.

It is required that the fuel leaving the tank should be clean so that contaminants do not build up and block the fuel line upstream of the separation device. Furthermore, there is a risk that additional fuel take-off lines may inadvertently be added upstream of the device. It is recognised that there may not always be space to house the separation device, for example on the forecourt of a fuel station where space is limited or on a portable tank.

With the foregoing in mind, in accordance with the present invention, there is provided a fuel pick-up device mountable to a fuel tank, the device having a head fittable to a wall of the tank, an elongate body which, in use, is configured to extend from the head into the tank and a separator disposed in the elongate body, the separator comprising an axially extending separation chamber, means for creating a helical flow of fuel through the device between an inlet and an outlet and within the separation chamber, wherein the inlet is disposed at a distal end of the separation chamber and the outlet is disposed at a proximal end of the separation chamber and centrally of the separation chamber, about the rotational axis of the helical flow of fuel, and wherein the outlet has a width which is substantially less than the width of the separation chamber, wherein any denser contaminants in the fuel entering the separation chamber through said inlet move radially outwardly in the helical flow away from the outlet, the outlet being arranged such that fuel drawn from the chamber is substantially free of any denser contaminants, means being provided in the elongate body for collecting any denser contaminants separated from the fuel, characterised in that the means for creating a helical flow of fuel comprises at least one helical guide vane disposed in the separation chamber, the at least one helical guide vane extending longitudinally of the separation chamber, wherein the separation chamber comprises an inner tubular sidewall which constrains the helical flow of fuel and the elongate body comprises an outer sidewall, the outlet extending axially inside the inner tubular sidewall from the proximal end thereof, the inner tubular sidewall comprising apertures through which the separated water can pass into a collection chamber disposed between the inner tubular sidewall of the separation chamber and the outer sidewall of the elongate body.

The device is mounted to a fuel tank such that the elongate body extends towards the bottom of the tank. In use, fuel is drawn through the device before it leaves the tank, so that the fuel leaving the tank is substantially free of water or other denser contaminants. In this manner the risk of contaminants building up and blocking the fuel line from the tank is avoided. Furthermore, the any additional fuel take-off lines added downstream of the device will always draw uncontaminated fuel.

The separation device is extremely effective at removing contaminants from the fuel and fuel can be drawn from a pick-up point which is close to the bottom of the tank. In this manner, less cleaning of the tank is required.

The separator is conveniently provided in a fuel pick-up device that extends into the tank without the need for any bulky external separation device.

The outlet is positioned centrally of the chamber about the rotational axis of the helical flow so that fuel is drawn from the radially innermost part of the helical flow.

The outlet has a width which is substantially less than the width of the separation chamber so that it is disposed radially inwardly of any separated water or other denser contaminants in the helical flow.

The means for creating a helical flow of fuel in the separation chamber may further comprise an inlet which is orientated to direct fuel tangentially of the rotational axis of the helical flow.

The axial distance between adjacent turns of the helical guide vane may decrease between the inlet and outlet, so that the rotational speed of the helical fuel flow increases towards the outlet.

The chamber comprises an inner tubular sidewall which constrains the helical flow of fuel and an outer sidewall, the outlet extending axially inside the inner tubular sidewall from the proximal end thereof, the proximal end of the sidewall being open to allow the separated water to flow into a collection chamber disposed between the inner and outer sidewalls.

In an embodiment which does not form part of the claimed invention, the chamber may comprise a tubular sidewall having a diameter which increases abruptly, such that any water in the helical flow is released into the wider portion of the chamber where it can collect.

The water collection means may be arranged to store water for removal from the device.

A duct may extend into the water collection means from the head to allow the water to be removed.

The outlet may open into an outlet chamber having a greater cross-sectional area than the outlet, such that the flow of fuel reduces and any water remaining in the flow reduces momentum and falls under the influence of gravity to a floor of the outlet chamber for collection.

A plurality of outlet chambers may be connected in series.

Also, in accordance with the present invention, there is provided an assembly comprising a fuel tank and a device as hereinbefore defined fitted to the tank.

Also, in accordance with the present invention, there is provided a method of fitting a device as hereinbefore defined to a fuel tank, the method comprising inserting the elongate body through an aperture in the tank such that the elongate body extends towards the bottom of the tank.

The method may comprise securing the head of the device to a wall of the tank.

Embodiments of a fuel pick-up device will now be described by way of examples only and with reference to the accompanying drawings, in which:.

Referring to <FIG> of the drawings, there is shown an embodiment of fuel pick-up device <NUM> having a flanged head <NUM>, which is secured around its periphery to the edges of an aperture <NUM> formed in the upper sidewall of a fuel tank <NUM>. The device <NUM> comprises an elongate tubular body <NUM> which extends into the tank <NUM> through the aperture <NUM> towards the bottom thereof. The body <NUM> defines a separator for <NUM> separating any water from fuel leaving the tank through the device <NUM>.

The tubular body <NUM> of the device <NUM> comprises a tubular sidewall <NUM>, which is closed at its distal end by a bottom end wall <NUM> provided with an inlet <NUM> through which fuel is drawn into the device <NUM>. The length of the tubular body <NUM> of the device <NUM> is selected so that the fuel inlet <NUM> is positioned adjacent the bottom wall of the tank <NUM>. In an alternative embodiment a float device of the kind disclosed in <CIT> or <CIT> may be positioned below the inlet <NUM>.

The inlet <NUM> opens into an elongate separation chamber <NUM> disposed inside the tubular body <NUM> of the device <NUM>. The separation chamber <NUM> comprises a tubular sidewall <NUM> having apertures <NUM>. A helical guide vane <NUM> extends longitudinally of the chamber <NUM> around an elongate axial support shaft <NUM>. The proximal end of the tubular sidewall <NUM> of the separation chamber <NUM> comprises an outlet <NUM> aligned with the proximal end of the shaft <NUM>.

A water drain duct <NUM> extends from the head <NUM> into a water collection chamber <NUM> disposed between the tubular sidewall <NUM> of the separation chamber <NUM> and the outer sidewall <NUM> of the body <NUM>. The outlet <NUM> opens into an upper outlet chamber <NUM> having a greater cross-sectional area than the outlet <NUM>. The bottom wall <NUM> of the outlet chamber <NUM> is provided with apertures <NUM> which open into the water collection chamber <NUM>. An outlet port <NUM> on the flanged head <NUM> extends into the outlet chamber <NUM>. The outlet port <NUM> is connected to an internal combustion engine or other device (not shown) which draws fuel from the tank <NUM> via the device <NUM>.

Fuel drawn into the device <NUM> from the tank enters through the inlet <NUM>, whereupon the helical guide vane <NUM> causes a helical flow of fuel inside the separation chamber <NUM> as the fuel flows towards the outlet duct <NUM>. The tubular sidewall <NUM> of the chamber <NUM> constrains the helical flow of fuel and any (heavier) water in the helical flow moves radially outwardly and passes into the collection chamber <NUM> through the apertures <NUM> in the tubular sidewall <NUM> of the chamber <NUM>. The (lighter) fuel in the helical flow is drawn radially inwardly into the apertured outlet duct <NUM> and onto the outlet <NUM>.

The fuel flowing out of the outlet <NUM> loses momentum as it flows into the wider outlet chamber <NUM>, such that any water remaining in the flow falls under the influence of gravity through the apertures <NUM> in the bottom wall <NUM> of the outlet chamber <NUM> into the water collection chamber <NUM>. Water W collected in the collection chamber <NUM> can be drained from the device via the water drain duct <NUM>.

Referring to <FIG> of the drawings, there is shown an alternative embodiment of fuel pick-up device <NUM> which does not form part of the presently claimed invention. It has a flanged head <NUM>, which is secured around its periphery to the edges of a circular aperture <NUM> formed in the upper sidewall of a fuel tank <NUM>. The device <NUM> comprises an elongate tubular body <NUM> which extends into the tank <NUM> through the aperture <NUM> towards the bottom thereof. The body <NUM> defines a separator for separating any water from fuel leaving the tank through the device <NUM>.

The tubular body <NUM> of the device <NUM> comprises an outer tubular sidewall <NUM>, which is closed at its distal end by a bottom end wall <NUM>. The tubular body <NUM> comprises an inner tubular sidewall <NUM> having a distal end which extends out of the bottom end wall <NUM> and defines an inlet <NUM>' through which fuel is drawn into the device <NUM>. The length of the tubular body <NUM> of the device <NUM> is selected so that the fuel inlet <NUM>' is positioned adjacent the bottom wall of the tank <NUM>. In an alternative embodiment a float device of the kind disclosed in <CIT> or <CIT> may be positioned below the inlet <NUM>'.

The inner tubular sidewall <NUM> defines an elongate separation chamber <NUM>. A helical guide vane <NUM> extends longitudinally of the chamber <NUM>. The axial distance between adjacent turns of the helical guide vane <NUM> decreases away from the inlet <NUM>', so that the rotational speed of the helical fuel flow increases towards an outlet duct <NUM>. The outlet duct <NUM> extends axially inside the inner tubular sidewall <NUM> from the proximal end thereof, the proximal end of the inner sidewall <NUM> being open. A water collection chamber <NUM> is disposed between the inner and outer sidewalls117, <NUM>. The outlet duct <NUM> is connected to an outlet port <NUM> on the flanged head <NUM>. The outlet port <NUM> is connected to an internal combustion engine or other device (not shown) which draws fuel from the tank <NUM> via the device <NUM>.

Fuel drawn into the device <NUM> from the tank <NUM> enters through the inlet <NUM>', whereupon the helical guide vane <NUM> causes a helical flow of fuel inside the <NUM> separation chamber <NUM> as the fuel flows towards the outlet duct <NUM>. The tubular inner sidewall <NUM> of the chamber <NUM> constrains the helical flow of fuel and any (heavier) water in the helical flow moves radially outwardly against the inner sidewall <NUM> and is carried upwardly in a laminar flow, whereupon it flows radially outwardly and downwardly into the collection chamber <NUM> through the open proximal end of the inner sidewall <NUM>. The outlet duct <NUM> is positioned centrally of the chamber <NUM> about the rotational axis of the helical flow, so that fuel free of water is drawn from the radially innermost part of the helical flow.

Referring to <FIG> of the drawings, there is shown an alternative embodiment of fuel pick-up device <NUM> which does not form part of the presently claimed invention. It has a flanged head <NUM>, which is secured around its periphery to the edges of a circular aperture formed in the upper sidewall of a fuel tank (not shown). The device <NUM> comprises an elongate tubular body <NUM> which extends into the tank through the aperture towards the bottom thereof. The body <NUM> defines a separator for separating any water from fuel leaving the tank through the device <NUM>.

The tubular body <NUM> of the device <NUM> comprises an outer tubular sidewall which is stepped in diameter and comprises an upper portion <NUM> which is of a greater diameter than a lower portion <NUM>. The distal end of the lower portion <NUM> defines an inlet <NUM>' through which fuel is drawn into the device <NUM>. The length of the tubular body <NUM> of the device <NUM> is selected so that the fuel inlet <NUM>' is positioned adjacent the bottom wall of the tank. In an alternative embodiment a float device of the kind disclosed in <CIT> or <CIT> may be positioned below the inlet <NUM>'.

The tubular sidewall of the device <NUM> defines an elongate separation chamber <NUM>. A helical guide vane <NUM> extends longitudinally of the chamber <NUM>. The diameter of the turns of the helical guide vane <NUM> increases away from the inlet <NUM>' towards an outlet duct <NUM>. The outlet duct <NUM> forms an outlet port on the flanged head 211which is connected to an internal combustion engine or other device (not shown) which draws fuel from the tank via the device <NUM>.

Fuel drawn into the device <NUM> from the tank enters through the inlet <NUM>', whereupon the helical guide vane <NUM> causes a helical flow of fuel inside the separation chamber <NUM> as the fuel flows towards the outlet duct <NUM>. The lower portion <NUM> of the tubular sidewall of the device constrains the helical flow of fuel and any (heavier) water in the helical flow moves radially outwardly against the inner sidewall and is carried upwardly in a laminar flow towards the upper portion <NUM>, whereupon it flows radially outwardly into a radial region <NUM> where it can be collected and drained. The outlet duct <NUM> is positioned centrally of the chamber <NUM> about the rotational axis of the helical flow, so that fuel free of water is drawn from the radially innermost part of the helical flow.

Claim 1:
A fuel pick-up device (<NUM>), mountable to a fuel tank (<NUM>), the device (<NUM>) having a head (<NUM>) fittable to a wall of the tank (<NUM>), an elongate body (<NUM>) which, in use, is configured to extend from the head (<NUM>) into the tank (<NUM>) and a separator disposed in the elongate body (<NUM>), the separator comprising an axially extending separation chamber (<NUM>), means for creating a helical flow of fuel through the device (<NUM>) between an inlet (<NUM>) and an outlet (<NUM>) and within the separation chamber (<NUM>), wherein the inlet (<NUM>) is disposed at a distal end of the separation chamber (<NUM>) and the outlet (<NUM>) is disposed at a proximal end of the separation chamber (<NUM>) and centrally of the separation chamber (<NUM>), about the rotational axis of the helical flow of fuel, and wherein the outlet (<NUM>) has a width which is substantially less than the width of the separation chamber (<NUM>), wherein any denser contaminants in the fuel entering the separation chamber (<NUM>) through said inlet (<NUM>) move radially outwardly in the helical flow away from the outlet (<NUM>), the outlet (<NUM>) being arranged such that fuel drawn from the separation chamber (<NUM>) is substantially free of any denser contaminants, means being provided in the elongate body (<NUM>) for collecting any denser contaminants separated from the fuel, characterised in that the means for creating a helical flow of fuel comprises at least one helical guide vane (<NUM>) disposed in the separation chamber (<NUM>), the at least one helical guide vane (<NUM>) extending longitudinally of the separation chamber (<NUM>), wherein the separation chamber (<NUM>) comprises an inner tubular sidewall (<NUM>) which constrains the helical flow of fuel and the elongate body (<NUM>) comprises an outer sidewall (<NUM>), the outlet (<NUM>) extending axially inside the inner tubular sidewall (<NUM>) from the proximal end thereof, the inner tubular sidewall (<NUM>) comprising apertures (<NUM>) through which the separated water can pass into a collection chamber (<NUM>) disposed between the inner tubular sidewall (<NUM>) of the separation chamber (<NUM>) and the outer sidewall (<NUM>) of the elongate body (<NUM>).