FUEL FILTER

Technical Field

The invention relates in general to a filter group for fuel which is destined to be associated to internal combustion engines of the diesel type. It is known that diesel fuel contains particles of water which must be separated from the fuel before it is supplied to the engine. Background Art

To this end filter groups have been developed, one of which is described in European patent no. EP 1229984, which comprise an external cylindrical container, provided with an inlet conduit and an outlet conduit for the fuel, the internal volume of which is separated by a water separating means into two chambers, lower and upper, which are inter-communicating. A filter wall is housed in the upper chamber, while the lower chamber is destined to collect the water which separates from the fuel thanks to the action of the separating means, which generally consists in a perforated platelet which by coalescence causes the separation of the water from the fuel. The water collected in the lower chamber is evacuated thanks to a special tap.

The solution described in the above-mentioned patent carries out its functions well, but exhibits some drawbacks.

The main drawback is that the size of the lower chamber is necessarily limited by the size of the filter group, which in turn must be commensurate with the size of the engine compartment, an often cramped space. This means that the chamber has to evacuated very frequently of the water collected therein. Disclosure of Invention The aim of the present invention is to obviate the drawbacks in the prior art with a simple and rational solution which involves an especially contained outlay in terms of costs.

The invention attains the above-cited aim thanks to a filter group exhibiting the technical characteristics recited in independent claim 1.

The dependent claims define details and advantageous embodiments of the invention.

Brief description of the Drawings

The characteristics and constructional advantages of the invention will emerge from the detailed description that follows, made with reference to the accompanying figures of the drawings, which illustrate, by way of non-limiting example, a particular and preferred embodiment of the invention. Figure 1 is a plan view of the filter group of the invention. Figure 2 is section N-Il of figure 1. Best Mode for Carrying Out the Invention

The figures illustrate the filter group 1 , which comprises a container 2, external and tray-conformed, a mouth of which is closed by a cover 3. The bottom 20 of the container 2 has a narrow and elongate shape and exhibits two sides 21 which are parallel to one another, the ends of which are joined by two curved portions 22.

A shaped element 4 is housed inside the container, which shaped element 4 comprises a horizontal plate 40, from which a first portion 41 rises vertically and is joined to the internal surface of the container 2, against which the first portion 41 rests, and a second portion 42, also known as a wall, which derives from an end of the first portion 41 and is arranged perpendicular thereto in order to define a vertical wall. The wall divides the internal volume of the container 2 into a first and a second chamber 5 and 6 which communicate with one another thanks to a vertical slot 7 afforded in the portion 42 defining the wall. As can be seen from the figures of the drawings, the two chambers 5 and 6 flank one another and develop in the direction of the height of the container.

A fuel inlet conduit 8 enters the chamber 5, entering above the cover 3; while an outlet conduit 9 exits the chamber 6, emerging therefrom below the bottom 20 of the container 2. A filter wall 10 is housed internally of the chamber 5, which filter wall 10 filters the fuel introduced into the fuel filter group through the inlet conduit 8.

In the illustrated embodiment, the filter wall 10 is toroid, but it could, in other embodiments of the invention, be of a different shape, for example flat. The shaped body 4 further comprises a horizontal upper plate 43 which is located below the cover 3 and has the function of preventing axial translations of the filter wall 10.

The fuel crossing the filter wall 10 passes into the second chamber 6, in which a separating means 11 is housed, which separating means 11 has the function of collecting the drops of water dispersed in the diesel fuel by coalescence, such as to separate the water from the diesel. Water has a higher specific gravity than diesel fuel, which causes the drops of water to tend to collect at the bottom of the chamber 6.

It is stressed that the phenomenon of coalescence of the drops of water is facilitated by the relatively slow speed of the fuel moving in the chamber 6. The fuel, in crossing the slot, is subjected to a sharp change in velocity, i.e. it speeds up as it crosses the slot 7, then slowing down internally of the chamber 6.

In the illustrated example the separating means 1 1 comprises a panel 12 which is supported by the shaped element 4 and is provided with a plurality of openings 120 which are closed by a usual hydrophobic net 121. In particular, a side of the hydrophobic net 121 rests on a step 410 afforded at the end of the portion 41 of the element 4, while the opposite side of the net 121 rests on a step 420 of the wall 42.

The water which collects on the bottom of the second chamber 6 is expelled through a usual means for evacuating 13, for example a usual tap valve located on the bottom of the chamber 6 itself. The fuel separated from the water exits from the second chamber through the outlet conduit 9. From the above description it can be seen that the filter group of the present invention advantageously provides a large water collection chamber which is able to collect a considerably greater quantity of water than known filter groups. In this way maintenance of the group can be less frequent, i.e. interventions to remove the water from the chamber are less frequently required.