TECHNICAL FIELD

The present invention relates to a filter group for fuel or lubricating oil in motoring applications, for example for automobiles, trucks, commercial vehicles and work machines, in hydraulic applications.

Filter groups generally comprise a casing constituted by a container, beaker- shaped, internally of which a filter cartridge is housed, and which is superiorly closed by a removable cover.

PRIOR ART

As is known, the filter cartridge must be periodically replaced after the vehicle has done a determined amount of travelling so as to guarantee a correct filtering of the impurities contained in the fluid (fuel or oil).

To avoid installing a non-compatible cartridge with the casing of the filter group and in order to facilitate the mounting of the filter cartridge internally of the casing, filter groups are known which are provided with inserting and orientating systems internally of the casing of the group.

One of these systems, such as the one described in document EP135571 1 , includes a pin associated to the cover of the casing and destined to be inserted internally of a housing comprised on the filter cartridge. In particular, in the solution described in the above document, the housing of the pin is fashioned internally of the cylindrical body of the cartridge. This solution, while effectively fulfilling its intention of preventing mounting errors of the cartridge, exhibits the drawback of reducing the useful filtering surface and reduces the general performance of the filter group.

Document US 20130062270 describes a slightly different solution which includes a pin branching inferiorly from the filter cartridge and is able to insert and occlude a housing (conduit) present on the bottom of the container of the casing, and at least a ribbing able to insert in a conjoined housing of the casing. While enabling a rapid and correct insertion of the cartridge in the casing, this solution makes the filter group not very compact and limits the possibility of use thereof. The aim of the present invention is to provide a filter group provided with an inserting and orientating system of the filter cartridge which does not reduce the general performance of the filter group and is at the same time compact. A further aim of the present invention is to attain the above-mentioned objective, with a solution that is simple, rational and relatively economical. These aims are attained by the characteristics of the invention as recited in the independent claim. The dependent claims delineate preferred and/or particularly advantageous aspects of the invention.

DISCLOSURE OF THE INVENTION

In particular, the invention provides a filter group comprising:

- an external casing internally of which a filter cartridge is housed, which filter cartridge is provided with a filter wall having a tubular shape defining an internal volume, a support plate (for example a lower support plate) being fixed to an end of the external casing, which lower plate exhibits a hole that is central with respect to a longitudinal axis of the cartridge,

- an inserting and orientating system of the filter cartridge internally of the external casing comprising a plug associated to the casing which exhibits a longitudinal axis parallel to the longitudinal axis of the cartridge and is able to insert in a complementary hole (100) present in the support plate, wherein the complementary hole crosses the thickness of the support plate and is offset with respect to the longitudinal axis of the cartridge and located radially on the plate at the internal volume of the filter wall.

With this solution, the inserting of the cartridge internally of the casing is made easy and prevents errors caused by inserting filter cartridges not compatible with the casing.

Further, the inserting and orientating system of the filter cartridge internally of the casing is practical and economical and enables obtaining a filter group which is compact without reducing the performance of the filter cartridge, the plug and the relative complementary hole being located at the internal volume of the filter wall.

In an aspect of the invention, a seal element is associated to the central hole and the offset complementary hole. This solution guarantees the separation between the dirty side and the clean side of the filter.

In a further aspect of the invention, the seal element is made in a single body which comprises a first gasket insertable in the central hole and a second gasket insertable in the offset complementary hole.

This solution is particularly advantageous as it enables making the mounting of the gasket on the filter cartridge more rapid.

In a different embodiment of the invention a filter cartridge is provided which comprises a filter wall having a substantially tubular shape, to an end of which a support plate is fixed, which support plate is provided with a central hole and an offset complementary hole, characterised in that a seal element is associated to the holes, which seal element is made in a single body which comprises a first gasket that can be inserted in the central hole and a second gasket that can be inserted in the complementary hole.

This solution is particularly advantageous as it enables making the mounting of the gasket on the filter cartridge easier and more rapid.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will emerge from a reading of the description that follows, provided by way of non-limiting example, with the aid of the figures of the accompanying tables.

Figure 1 is a view of a longitudinal section of a filter in an embodiment of the present invention.

Figure 2 is a section view of a portion of figure 1 .

Figure 3 is a view of a longitudinal section of the filter cartridge according to a first embodiment of the invention.

Figure 4 is a perspective cutaway view of a portion of the casing of the filter group.

Figure 5 is a perspective cutaway view of a first embodiment of the filter cartridge of the invention.

Figure 6 is a larger-scale view of a longitudinal section of a portion of the filter group of figure 1.

Figure 7 is a larger-scale view of a longitudinal section of a portion of the filter cartridge in a further embodiment of the invention. Figure 8 is a seal element used by the invention.

PREFERRED EMBODIMENT OF THE INVENTION

The filter group 10 shown in figure 1 is a filter group for fuel, in particular diesel oil, destined to be applied in internal combustion engines, in particular Diesel engines.

The filter 10 comprises an external casing, denoted in its entirety by 20, which is formed by a beaker body 21 and by an upper cover 22, that can be associated to the beaker body 21 for closing the casing 20.

The cover 22 comprises an inlet conduit 23 for the diesel to be filtered and an outlet conduit 24 for the filtered diesel, while the beaker body 21 exhibits a discharge hole 25, closed by a cap 26, for the water which can accumulate on the bottom of the beaker body 21.

A single-body component 30 is housed internally of the casing 20, which single-body component 30 comprises a broadened upper portion 30, which is housed in a corresponding seating fashioned in the cover 22, and a lower stem portion 32 which is welded to the broadened portion 31 and which develops axially in a downwards direction internally and in the centre of the beaker body 21 .

A sleeve 40 is coaxially inserted on the stem portion 32, an upper end of which sleeve 40 exhibits a substantially flat flange 41 solidly constrained to the broadened portion 31 of the single-body component 30.

The sleeve 40 is dimensioned so as to define, with the stem portion 32, a gap

43 in communication with the inlet conduit 23 of the diesel to be filtered through a connecting channel (not visible in the figures) which is fashioned in the broadened portion 31 of the single-body component 30.

The broadened portion 31 incorporates an electric heater (not visible) able to heat the diesel which flows into the connecting channel, which is electrically supplied by means of an electric socket 33 projecting externally of the cover

22.

A disc-shaped plate 50 is inserted, with the interposing of a seal ring, on the sleeve 40. The plate 50 comprises a central hole 51 for coupling with the sleeve 40 and slightly-raised perimeter edge to which an annular gasket 52 is strictly coupled, able to sealingly act against an internal lateral surface of the cover 22.

The plate 50 substantially sub-divides the internal volume of the casing into a first upper chamber 200 and a first lower chamber 201 , which are in communication with one another due to at least a passage opening 53 (figures 1 , 3 and 6) present in the plate 50.

A filter cartridge, denoted in its entirety by 60, is housed internally of the beaker body 21 , and in particular in the lower chamber 201 , which filter cartridge 60 comprises an upper support plate 61 and a lower support plate 62, which are fixed to the opposite ends of a tubular filter wall 63.

The filter wall 63 defines and delimits a substantially-cylindrical internal volume 64 in communication with the inlet conduit 23 of the fuel, and an external volume 65, delimited by the beaker body 21 and the plate 50, in communication with the outlet conduit of the fuel through the passage openings 53.

In the illustrated embodiment the filter wall 63 comprises a polymer depth wall. Other embodiments of the invention can, otherwise, have a star-conformed filter wall.

With reference to figure 3, the upper support plate 61 and the lower support plate 62 exhibit a respective central hole, denoted respectively with reference numerals 610 and 620, which are aligned to one another and centre on a longitudinal axis A of the filter cartridge 60, of the filter wall 63 and of the filter group 10.

The central hole 610 of the upper support plate 61 is inserted on the sleeve 40 (figure 1 , figure 6), with an interposing of a seal ring, so that the star-shaped portion 32 of the single-body component 30 axially crosses the whole internal volume 64 of the filter cartridge 60 up to inserting in the central hole 620 of the lower support plate 62 (figure 1 ).

The free end of the star-shaped portion 32 projects beyond the lower support plate 62, where it bears a level sensor 34 able to detect the water level which accumulates on the bottom of the beaker body 21 during the diesel fuel filtration.

The level sensor 34 is associated to electrical connecting means which are incorporated in the single-body component 30 and which reach the electric socket 33, by means of which the level sensor 34 is connected to an electronic control board (not illustrated) of the vehicle.

The lower plate 62 bears on a top thereof one or more ribs, for example three ribs 70, 71 , 72, angularly spaced from one another, which rise from a bottom end of the beaker body 22. The angular distance separating the ribs is preferably not constant, i.e. the angle separating the ribs 70, 71 can be different from the angle separating the ribs 71 and 72, which can be different from the angle which separates the ribs 72 and 70.

In particular, an annular shank 80 branches inferiorly from the lower plate 62, which annular shank 80 exhibits one or more lower openings, in the example three lower openings 81 , which are slit-shaped and develop up to the lower edge of the annular shank 80 and which are angularly spaced from one another by angles equal to the angles separating the ribs 70, 71 and 72, so that each of the ribs 70, 71 and 72 is inserted in a corresponding opening 81 . In the present embodiment of the invention each opening 81 comprises two lateral walls 82 (figure 5) parallel to one another and facing towards the inside of the annular shank 80.

Further, the annular shank 80 also exhibits a plurality of windows 83 for the passage of liquid arranged perimetrally on the lateral surface thereof.

The filter group of the invention comprises an inserting and positioning system of the filter cartridge 60 internally of the casing 20. In detail, in the illustrated embodiment, the inserting and positioning system of the filter cartridge 60 comprises a plug 90 associated to the casing 20.

In particular, the plug 90 rises from the rib 70 and exhibits a longitudinal axis B parallel to the longitudinal axis A of the filter cartridge 60 and is able to insert in a complementary hole 100 present in the lower support plate 62. The height of the plug 90, i.e. the axial dimension thereof with respect to the top of the rib 70, is preferably lower than the height of the annular shank 80 of the cartridge 60, i.e. the axial dimension thereof with respect to the bottom of the lower plate 62.

In this way, during the mounting of the cartridge 60, the lower edge of the annular shank 80 rests first on the ribs 70, 71 and 72, without the plug 90 interfering with the lower plate 62. At this point, the cartridge 60 can easily be rotated internally of the beaker body 21 , up to aligning the openings 81 with the respective ribs 70, 71 and 72. The reaching of this alignment is easily observed since in this configuration the cartridge 60 is free to slide axially towards the bottom of the beaker body 21 . As the angular distance between the ribs 70, 71 and 72 is not constant, the above-described alignment is obtained only by a precise angular position of the cartridge 60, which corresponds to the position in which the plug 90 is aligned with the complementary hole 100. From this position, simply by pushing the cartridge 60 towards the bottom of the beaker body 21 , it is therefore possible to obtain insertion of the ribs 70, 71 and 72 in the openings 81 , as well as the insertion of the plug 90 in the complementary hole 100, in this way completing the assembly.

As can be seen in figures 1 , 2, 4 and 5, the complementary hole 100 crosses the thickness of the lower support plate 62 and is offset with respect to the longitudinal axis A. In particular the complementary hole 100 is radially located on the plate at the internal volume 64 of the filter wall 63. The complementary hole 200 can therefore be a through-hole and can be separate with respect to the central hole 620.

The fact that the complementary hole 100 is located radially on the plate at the internal volume 64 of the filter wall 63 is particularly advantageous since it enables obtaining a filter group having smaller radial dimensions than those of the prior art, without reducing the filtering power of the filter wall.

A seal element 1 10 is associated to the central hole 620 and the offset complementary hole 100, which seal element is in particular illustrated in figure 8. In the illustrated embodiment the seal element 1 10 is realized in a single body 1 1 1 which comprises a first gasket 1 12 that can be inserted in the central hole 620 and a second gasket 13 able to be inserted in the complementary hole 100.

This solution is particularly advantageous as it simplifies and accelerates the mounting operations of the seal element during the production of the cartridge. The seal element 1 10 can be made for example of FVMQ (fluorosilicone) or alternatively of HNBR (Halogenated Acryonitrile Butadiene).

Alternatively, the lower support plate 62 might be entirely made of an elastomer material, for example fluorosilicone or hydrogenated butadiene acrylonitrile or polurethane, so that the two holes 620 and 100 fashioned therein are in themselves able to create a seal respectively on the stem portion 32 and on the plugs 90, without the need to predispose and mount further seals.

In other embodiments, the lower support plate 62 might be made of a rigid material as in the first embodiment, but for example comprise a single central opening, having larger dimensions with respect to the central hole 620, which can be closed by a single seal element (for example disc-shaped) in which both the central hole 620 and the complementary hole 100 are fashioned, as in the second embodiment. In this case too, the seal element might be made of an elastomer material, for example fluorosilicone or hydrogenated butadiene fluorisilicone or polyurethane, and might be applied to the lower support plate 62 by means of co-moulding, gluing or any other known system.

In an embodiment, the lower plate might comprise a reticular structure made of a rigid material able to support the axial end of the filter wall. The reticular structure is at least partly covered by a layer of an elastomer material, for example fluorosilicone or hydrogenated butadiene acrylonitrile or polurethane, so that the two holes 620 and 100 fashioned therein are in themselves able to create a seal respectively on the stem portion 32 and on the plugs 90, without the need to predispose and mount further seals.

In particular, the annular shank 80 might be branched inferiorly from the lower plate 62, which annular shank 80 exhibits one or more lower openings, in the example three lower openings 81 , which are slit-shaped and develop up to the lower edge of the annular shank 80 and which are angularly spaced from one another by angles equal to the angles separating the ribs 70, 71 and 72, so that each of the ribs 70, 71 and 72 is inserted in a corresponding opening 81. In the embodiment illustrated in the figures, the upper support plate 61 of the filter cartridge 60 comprises an upper shank 68 that can be hooked by hook means of the plate 50. The hook means comprise a plurality of teeth 57, L-shaped and projecting inferiorly from the plate 50.

The teeth 57 are elastically yielding and the end portion thereof is conformed so as to insert in corresponding recesses 69 of the upper shank 68, giving rise to a constraint by means of a radial snap-coupling such as to removably constrain together the plate 50 and the upper support plate 61.

With the above-described configuration, the filter cartridge 60 sub-divides the internal volume of the beaker body 21 into a first chamber, coinciding with the internal volume of the filter wall 63, which communicates with the inlet conduit 23 of the diesel fuel to be filtered, and a second chamber 65, defined externally of the filter wall 63, which communicates with the outlet conduit 24 via the plurality of passage openings 53 which are afforded in the plate 50.

In the present embodiment of the invention, illustrated in figures from 1 to 6, the passage openings 53 of the plate 50 are intercepted by a flat filter wall 55 (figures 5, 6) which is fixed to the lower surface of the plate 50 where it lies in a perpendicular plane to the axis A of the filter wall 63.

Alternatively, the flat secondary wall 55 might be fixed to the upper surface of the plate 50.

The flat filter wall 55 is preferably a hydrophobic wall, which exhibits a substantially disc shape with an external diameter that is not greater than the diameter of the plate 50.

Further, the filter wall 55 generally exhibits a greater porosity than the filter wall 63 of the filter cartridge 60.

It is specified that in other embodiments of the invention, such as for example the embodiment illustrated in figure 7, no flat secondary filter wall is associated to the openings 53.

In the light of what is described above, the functioning of the filter 10 is the following.

The diesel fuel to be filtered enters the inlet conduit 23 and, via the connecting channel (not illustrated) afforded in the single-piece component 30 flows into the internal volume 64 of the filter wall 63.

During this passage, the diesel fuel can be heated by the heater which is incorporated in the broadened portion 31 of the single-body component 30. The diesel fuel is forced to flow from the internal volume 64 radially through the filter wall 63, from inside towards outside, and to flow into the second chamber 65.

In this way the filter wall 63 retains the impurities which might be present in the diesel fuel.

In the embodiment of the invention illustrated in figures from 1 to 7, the diesel fuel flowing from the chamber 65 crosses the flat filter wall 55 which, having a greater porosity than the filter wall 63, mainly has the function of separating, by coalescence, the water which can be contained in the diesel fuel.

The water separated from the diesel fuel collects on the bottom of the beaker body 21 and, when the accumulated water level reaches the sensor 34, the sensor 34 sends a signal to the vehicle control board following which the accumulated water is discharged from the filter 10 through the profiled pipe 56 and the discharge conduit 25.

After having crossed the flat filter wall 55, the diesel fuel finally reaches the outlet conduit 24.

Differently, in an embodiment of the invention illustrated in figure 7, the diesel fuel flows from the second chamber 65 directly towards the outlet conduit 24 through the openings 53, no hydrophobic wall being included associated to the above-mentioned openings 23.

Lastly it is specified that some embodiments of the invention do not include use of a heater which comprises a stem 32. In these cases however a tubular element is included (not illustrated, able to cross the internal volume 64 of the cartridge and inserted in the holes 610 and 620 thereof, identical seal elements being interposed to the seal elements described for maintaining the clean side and the dirty side of the filter group separate. The tubular element can be used with different functions according to the applications and/or the configuration for which the filter group is destined, for example it can be one of the components used for the inlet or outlet of the fluid from the filter group or, for example, it can constitute a housing for sensor used for monitoring the correct functioning of the filter. It is further specified that the invention includes some embodiments in which the central hole 620 and the complementary hole 0 are made on the upper plate of the cartridge and interact equivalently with the stem of a sensor group (or with a tubular element integrated in the housing) and a plug 90 branching from the upper portion of the external casing 20 of the filter group in the internal volume of the filter group.

Obviously a technical expert in the sector might make numerous modifications of a technical-applicational nature to the filter 10 as described in the foregoing, without forsaking the scope of protection of the invention as claimed in the following.