"FILTER CARTRIDGE FOR A FUEL FILTER GROUP"

Field of application

[0001] The present invention relates to a filter cartridge of a filter group of a fuel, preferably of the diesel type. The present invention also relates to said filter group comprising the filter cartridge.

[0002] The present invention finds its preferred application in the automotive sector. Specifically, in fact, the context in which the filter cartridge lies, is that specific to the filtration from diesel fuel of unwanted elements of both the solid and liquid type. In fact, the present filter cartridge is suitable to filter from the fuel unwanted solid particles, and at the same time is suitable to filter from the fuel water particles dissolved in it.

[0003] Solutions of filter cartridges suitable for performing such operations are known in the automotive context .

[0004] The typical problem of such known filter cartridges is that of presenting complex shapes and geometries, especially with reference to those portions necessary for the sealed engagement of the filter body.

Solution according to the invention

[0005] The purpose of the present invention is therefore to provide a filter cartridge that solves the aforesaid problem, presenting in a simple and functional form all the characteristics necessary for an effective filtration of the fuel and at the same time all the specific portions for the sealed engagement with the filter body.

[0006] This is achieved by the filter cartridge claimed in claim 1 and by the filter group claimed in claim 13. The dependent claims show preferred embodiments involving further advantageous aspects.

Description of the drawings

[0007] Further characteristics and advantages of the invention will, in any case, be evident from the description given below of its preferred embodiments, made by way of a non-limiting example with reference to the appended drawings, wherein:

[0008] - fig. 1 shows a schematic cross-section view of the filter group according to the present invention, according to a preferred embodiment;

[0009] - fig. 2 shows a cross-section view of a filter cartridge according to the present invention, according to a preferred embodiment, as shown by way of example in figure 1;

[0010] fig. 3 shows a perspective view from the bottom of the filter cartridge in figure 2;

[0011] - fig. 4 shows a schematic cross-section view of the filter group according to the present invention, according to a further preferred embodiment;

[0012] fig. 5 shows a perspective view from the bottom of the filter group according to the present invention, according to a further preferred embodiment, as shown by way of example in figure 4;

[0013] - fig. 6 shows a schematic cross-section view of the filter group according to the present invention, according to yet a further preferred embodiment;

[0014] - fig. 7 shows a cross-section view of a filter cartridge according to the present invention, according to a further preferred embodiment, as shown by way of example in figure 6;

[0015] fig. 8 shows a perspective view from the bottom of the filter cartridge in figure 7;

[0016] - fig. 9 shows a schematic cross-section view of the filter group according to the present invention, according to yet a further preferred embodiment;

[0017] - fig. 10 shows a cross-section view of a filter cartridge according to the present invention, according to a further preferred embodiment, as shown by way of example in figure 9;

[0018] - fig. 11 shows a perspective view in separate parts of the filter cartridge of the present invention.

[0019] Detailed description [0020] In the appended drawings, reference numeral 1 globally denotes a filter cartridge for filtering fuel, preferably of the diesel type. Reference numeral 900 denotes a filter group comprising the filter cartridge 1 and a filter body 500 housing said filter cartridge 1.

[0021] According to the present invention, the filter cartridge 1 for filtering fuel is suitable to perform a filtering action on the suspended particles and a separation action of water particles from said fuel. In other words, the filter cartridge 1 performs both a solid filtration and a separation between liquids. The filter cartridge 1 is suitable to be intercepted by dirty fuel (containing impurities and suspended particles and a quantity of water particles) and as a result of its actions to return clean fuel (first filtered of the suspended particles, and secondly separated of the water, collected separately in the filter body) .

[0022] According to the present invention, the filter body 500 comprised in the filter group 900, in turn object of the present invention, in addition to being suitable to be fluidly connected to the vehicle's fuel circulation system, is specially shaped to house said filter cartridge 1.

[0023] In particular, the filter body 500 is shaped to engage with the filter cartridge 1 in a raised position relative to a bottom wall 501 so as to identify a water collection chamber 550.

[0024] Preferably, in fact, the filter body 500 comprises support elements 505 that extend in height from the bottom wall 501 to be engaged or vice versa to engage the filter cartridge 1. In one embodiment, the support elements 505 extend laterally from the side walls of the filter body 500.

[0025] In a preferred embodiment, the support elements 505 define a planar support wall 506, substantially parallel to the bottom wall 501, which is sealingly engageable axially by the lower seal 6 so as to seal the water collection chamber 550 and keep the dirty side of the filter separate from the clean side communicating above with the output opening 500b and below with the water collection chamber 550.

[0026] According to a preferred embodiment, the planar support wall 506 comprises a through opening 508 delimited by a continuous annular edge 507.

[0027] The filter group 900 of the present invention, and, therefore, both the filter body 500 and the filter cartridge 1 are specifically suitable for working vertically, as shown by way of example in Figures 1, 4, 6 and 9, where fuel and water flows are also schematised.

[0028] According to the present invention, the filter body 500 comprises an input opening 500a for the input of the fuel to be filtered, coming from the tank, and a central output opening 500b for the filtered fuel, to be fed to the internal combustion engine.

[0029] According to the present invention, the filter cartridge 1 extends along a main axis X-X. Preferably, the filter body 500 also extends along an axis: preferably, also for the filter body 500 and the filter group 900 the main axis X-X is identified as the extension axis.

[0030] According to the present invention, the fuel to be filtered is fed through the input opening 500a on the outer side of the filter cartridge 1.

[0031] The filter cartridge 1 comprises an annular-shaped filter medium 3, suitable for filtering the fuel passing through it from the outside to the inside, defining with an inner wall 31 a central cavity 30 along the main axis

X-X.

[0032] Preferably, the filter medium 3 is crossed by the fuel in the radial direction.

[0033] Preferably, the filter medium 3 is of the pleated type in the form of a star or is a depth septum made in the form of a tubular septum.

[0034] Said filter medium 3 is sandwiched between an upper end plate 2 and a lower end plate 4. [0035] The upper end plate 2 is positioned on the upper end of the filter medium 3 and has an upper opening 20 at the main axis X-X. Said upper opening 20 is suitable to be fluidly connected to the central output opening 500b.

[0036] The lower end plate 4 is positioned on the lower end of the filter medium 3 and has a lower opening 40 at the main axis X-X. In other words, the upper opening 20, central cavity 30 and lower opening 40 are mutually aligned. Said lower opening 40 is suitable to be fluidly connected to the water collection chamber 550.

[0037] As shown in the appended drawings, the upper opening 20 and lower opening 40 are smaller than the central cavity 30.

[0038] According to a preferred embodiment, said end plates are integrally connected to the filter medium 3, preferably by welding or bonding. According to a preferred embodiment, the end plates are made of plastic such as, for example, nylon-based and/or polyester-based materials .

[0039] In addition, the filter cartridge 1 of the present invention comprises a water separator group 5 that extends around the main axis X-X located in the central cavity 30. Preferably, the water separator group 5 is positioned between the upper end plate 3 and the lower end plate 4. Preferably, the water separator group 5 is engaged to the upper end plate 3 and/or the lower end plate 4.

[0040] According to the present invention, the water separator group 5 comprises a hydrophobic septum 52, radially spaced from the inner wall 31 delimiting an annular duct 100, in which the water stopped by said hydrophobic septum 52 flows.

[0041] Preferably, moreover, the water separator group 5 and the lower end plate 4 delimit in the lower opening 40 at least one through opening 45 fluidly connected with said annular duct 100. Through said through opening 45, water flows towards the water collection chamber 550.

[0042] According to a preferred embodiment, the water separator group 5 comprises a support structure 51 suitable to rest with certain specific portions on an inner wall 31 of the filter medium 3. Preferably, said support structure 51 comprises a plurality of radial through openings 515 through which fuel flows towards the output .

[0043] In addition, said hydrophobic septum 52 is supported by the support structure 51. In particular, the hydrophobic septum 52 is positioned at said radial through openings 515. Preferably, the hydrophobic septum

52 is housed on the inner tubular structure.

[0044] In other words, the hydrophobic septum is located downstream of the filter medium 3 so that the two elements are crossed in series by the flow of fuel, preferably in the radial direction.

[0045] According to a preferred embodiment, the hydrophobic septum 52 comprises a fibre mesh with a hydrophobic surface. The term "hydrophobic surface" is understood to mean a material which in contact with water droplets forms an average contact angle of equilibrium equal to or greater than 90° (sexagesimal degrees) .

[0046] Preferably, the hydrophobic septum 52 is made of polyester, preferably polyethylene terephthalate (PET) , coated in hydrophobic material for example silicone or fluorinated material.

[0047] In yet other words, the hydrophobic septum 52 is supported by the support structure 51 having a substantially cylindrical shape such that between the hydrophobic septum 52 and the inner wall 31 an annular duct 100 is created through which drops of water created on the wall of the hydrophobic septum 52 radially crossed by the fuel, flow.

[0048] According to a preferred embodiment, the support structure 51 comprises multiple portions. The support structure 51 comprises an outer portion suitable to support the filter medium 3 and an inner portion suitable to support the hydrophobic separator 52. [0049] For example, according to a preferred embodiment, the support structure 51 comprises an inner tubular structure and an outer tubular structure respectively one concentric to the other, respectively radially separated from each other, wherein both structures comprise a plurality of radial through openings 515.

[0050] According to a preferred embodiment, the support structure 51 comprises chute portions 510 extending along circumferential portions relative to the main axis X-X.

[0051] Preferably, said chute portions 510 are placed between the outer surface of the hydrophobic septum 52 and the inner wall 31 of the filter medium 3.

[0052] Preferably, said chute portions 510 have an inclination such as to favour the flow of water around the outer surface of the hydrophobic septum 52 towards the through opening 45. In other words, the water, intercepted by the hydrophobic septum 52, upon gravitational action flows towards the bottom of the filter body 500, i.e. into the water collection chamber 550.

[0053] According to a preferred embodiment, the through opening 45 has an annular shape.

[0054] According to a preferred embodiment, the support structure 51 extends, between the upper end plate 3 and the lower end plate 4. Preferably, the support structure is firmly engaged between the upper end plate 3 and the lower end plate 4.

[0055] According to the present invention, moreover, the filter cartridge 1 comprises a lower seal 6 having an annular extension positioned on the lower end plate 4 to sealingly engage the filter body 500 in the axial direction .

[0056] Preferably, the lower seal 6 sealingly engages the filter body 500 on the planar support wall 506.

[0057] According to a preferred embodiment, the lower end plate 4 comprises an annular groove 46 suitable to house at least partially the lower seal 6.

[0058] Preferably, said annular groove 46 comprises a first annular abutment wall 46' extending in height parallel to the main axis X-X. Preferably said first annular abutment wall 46' is distal to the X-X axis.

[0059] Preferably, said annular groove 46 comprises a second annular abutment wall 46" extending in height parallel to the main axis X-X. Preferably said second annular abutment wall 46" is proximal to the X-X axis.

[0060] According to a preferred embodiment, the lower seal 6 comprises a head portion 61 engaged to the lower end plate 4 and a sealing portion 62 axially spaced apart therefrom, suitable to engage the filter body 500.

[0061] According to an embodiment variant, said head portion 61 is suitable to engage the first annular abutment wall 46' . According to a preferred embodiment, the first annular abutment wall 46' is inserted inside the head portion 61.

[0062] According to a preferred embodiment, the head portion 61 is housed in the annular groove 46.

[0063] According to one embodiment, the lower seal 6 has a toroidal shape having a diameter substantially equal to the width of the annular groove 46.

[0064] Preferably, the lower seal 6 has a substantially rectangular cross-section having a width substantially equal to the width of the annular groove 46.

[0065] Preferably, the lower seal 6 is integrally positioned in the groove 46 fixed, e.g., glued, to the lower end plate 4.

[0066] According to a preferred embodiment, the sealing portion 62 has at least two sealing lips 62', 62" positioned at different radial distances relative to the main axis X-X so as to have two annular sealing portions which engage the filter body 5. In other words, two sealing rings 506' , 506" are created on the planar support wall 506" in contact with the two sealing lips 62’, 62".

[0067] That is to say, radially on the planar support wall 506 two sealing rings are created, radially spaced apart from each other.

[0068] According to a preferred embodiment, the lower seal 6 has a substantially "X" or "U" shaped cross-section.

[0069] According to a further preferred embodiment, the lower seal 6 is of the lip type, with a substantially "C" shaped cross-section.

[0070] According to a preferred embodiment, the lower seal 6 comprises a recess 600 suitable for accommodating in the space defined therein the deformation of the lower seal 6.

[0071] Preferably, said recess 600 is facing upwards. In other embodiments, said recess is facing downwards. In other embodiments, said recess is radially oriented outwards toward the dirty side of the filter cartridge 1. In other embodiments, said recess is oriented inwards toward the clean side of the filter cartridge. In further embodiments, the lower seal 6 comprises more than one recess. In further embodiments, the lower seal 6 comprises a combination of the recesses described above.

[0072] According to a preferred embodiment, the filter cartridge 1 comprises a plurality of locking teeth 48 suitable to engage the filter body 500, in particular its planar wall 506.

[0073] Preferably, the engagement of the locking teeth 48 to the filter body 500 axially preloads the lower seal 6. In other words, the engagement of the locking teeth 48 to the filter body 500 flattens the lower seal 6.

[0074] According to a preferred embodiment the locking teeth 48 are comprised, preferably integrally, in the lower end plate 4.

[0075] According to a preferred embodiment the locking teeth 48 are comprised, preferably integrally, in the water separation group 5, in particular with its support structure 51.

[0076] According to a preferred embodiment, the locking teeth 48 are angularly spaced relative to the main axis

X-X.

[0077] According to a preferred embodiment, the locking teeth 48 are positioned at the edges of the lower opening 40. According to a preferred embodiment, the locking teeth 48 extend axially.

[0078] According to a preferred embodiment the locking teeth 48 are two in number; positioned diametrically opposite the X-X axis of the lower opening 40.

[0079] According to a preferred embodiment the locking teeth 48 are four in number placed 90° apart from each other relative to the X-X axis at the edges of the lower opening 40.

[0080] According to a preferred embodiment, the locking teeth 48 are suitable to snap-engage the planar wall 506. In particular, in fact, the locking teeth 48 are suitable to engage the continuous annular edge 507 of the planar wall 506.

[0081] According to a preferred embodiment, the locking teeth 48 comprise a hooking portion facing radially outwards to engage the continuous annular edge 507 of the through opening 508 of the planar wall 506, preferably on the edge facing towards the inside of the water collection chamber 550.

[0082] According to a preferred embodiment, said locking teeth 48 are elastically yielding and comprise a hooking surface 481, such that the locking teeth 48 snap-engage the filter body 500.

[0083] Preferably, the locking teeth 48 extend axially parallel to the X-X axis and the hooking surfaces 481 extend outwardly, for example radially relative to the X- X axis. In other words, each locking tooth 48 comprises a stem extending parallel to the X-X axis and a hooking surface 481 extending orthogonally from the stem.

[0084] According to a preferred embodiment, the locking teeth 48 engage the filter body 500 allowing the rotation of the filter cartridge 1 around the X-X axis.

[0085] According to a preferred embodiment, thanks to the locking teeth 48 the filter cartridge 1 is locked to the filter body 500 exclusively in the axial direction, being, in fact, rotationally free: the locking between the filter cartridge 1 and the filter body 500 allows the rotation of the filter cartridge 1 around the X-X axis.

[0086] According to a preferred embodiment, the filter body 500 consists of two half-shells 500' , 500" which are screwable to each other; the screwing of the two half shells 500', 500" allows the tightening of the filter body 500, the axial tightening of the filter cartridge 1 and involves a further axial flattening action of the seal 6.

[0087] According to a preferred embodiment, said screwing is allowed and assisted by the fact that the filter cartridge 1 is hooked to the filter body coaxially to the X-X axis; according to a preferred embodiment, the filter cartridge 1 is free to move in rotation with respect to the X-X axis, i.e., for example, it is free to move in rotation during the screwing action of the two half shells 500', 500"; in other words, the filter cartridge 1 avoids opposing the relative rotary motion of the two half-shells 500', 500".

[0088] According to a preferred embodiment, the annular groove 46 is radially spaced from the main axis X-X, being radially distant from the edge 41 defining the lower opening 40. Preferably, the lower seal 6 is positioned approximately in a position proximal to the outer perimeter edge 42 of the lower end plate 4.

[0089] According to one embodiment variant, the annular groove 46 is radially proximal to the edge 41 defining the lower opening 40. Preferably, the lower seal 6 is positioned approximately in a position proximal to the axial locking teeth 48. Preferably, the lower seal 6 is positioned approximately proximally to the lower opening 40.

[0090] According to a preferred embodiment, the groove 46 is bounded on the inner side by a second annular abutment wall 46". According to a preferred embodiment such second annular abutment wall 46" is formed by the locking teeth 48. According to a preferred embodiment the groove 46 is delimited on the inner side by the second annular abutment wall 46" having a circular extension and from said second annular abutment wall 46" the locking teeth 48 extend.

[0091] According to such preferred embodiments the second annular abutment wall 46" is such as to provide an abutment also in the radial direction, towards the X-X axis at the lower seal 6.

[0092] According to a further embodiment, the annular groove 46 is radially approximately at the centre of the space between the edge 41 defining the lower opening 40 and the outer perimeter edge 42. [0093] According to the present invention, it may be noted how each of the features described above and shown in the drawings relative to a specific embodiment are integrable in another embodiment. For example, with reference to the attached drawings, different embodiments of the lower seal 6 are integrable into the filter cartridge 1 provided with axial teeth 48.

[0094] Innovatively, the filter cartridge and the filter group comprising the cartridge fully satisfy the purpose of the present invention overcoming the drawbacks typical of the prior art.

[0095] Advantageously, in fact, the lower sealing is guaranteed by the lower seal by a simple axial action.

[0096] Advantageously, the geometry of the filter cartridge is extremely simplified compared to state-of-the-art solutions .

[0097] Advantageously, the geometry of the seal is suitable to promote an optimal sealing action with the planar support wall.

[0098] Advantageously, the seal has a profile with sealing lips and/or compensating portions and/or suitably shaped recesses to facilitate the tightening of the seal and ensure it is kept in the working position minimizing unwanted leakage.

[0099] Advantageously, the locking teeth promote the axial sealing action.

[00100] Advantageously, the locking teeth allow the filter cartridge to be fixed to the filter body, and in particular to the portion thereof on which the sealing surface is provided; advantageously, thanks to the locking teeth, a pre-loading of the seal is obtained avoiding unwanted displacements of the cartridge during the assembly phases of the filter body and handling of the group during the maintenance phases.

[00101] Advantageously, the locking teeth positioned concentrically to the axis of the seal make it possible to guide the thrust action of the filter body on the filter cartridge and on the seal and consequently ensure the complete and uniform tightening of the seal.

[00102] Advantageously, the locking teeth maintain the alignment between the lower opening and the through opening ensuring that the through cross-section of the through opening is maintained.

[00103] Advantageously, clamping forces are effectively transferred from the upper shell to the lower seal via the locking teeth.

[00104] Advantageously, thanks to the locking teeth, the seal between the filter cartridge and the filter body is maintained even in embodiments in which the filter body has inside it inclined, concave and/or convex surfaces, in which such surfaces cooperate with the filter cartridge to facilitate in turn the seal between the components.

[00105] Advantageously, the locking teeth make it possible to keep the filter cartridge in place even when the filter cartridge needs to be replaced, allowing its extraction only with the opening of the filter group and greatly improving the cleanliness of the replacement operation .

[00106] Advantageously, the locking teeth allow the relative rotation between the two half-shells without opposing it.

[00107] It is clear that a person skilled in the art may make modifications to the filter cartridge and/or to the filter group described above so as to satisfy contingent requirements, all contained within the scope of protection as defined by the following claims.

[00108] List of reference numbers:

1 filter cartridge

2 upper end plate

20 upper opening

3 filter medium

30 central cavity

4 lower end plate

40 lower opening 41 central edge

42 perimetral edge

45 through opening

46 groove

46' first annular abutment wall

46" second annular abutment wall 48 locking teeth

5 separation and support group

51 support structure

510 chute portions

515 radial through openings

52 water separation wall

500 filter body

501 bottom wall

505 support elements

506 planar support wall

506' 506 sealing rings

507 continuous annular edge

508 through opening

550 water collection chamber

500a input opening

500b central output opening 500' 500" half-shells

6 bottom seal

61 head portion 62 sealing portion 62', 62" sealing lips

600 recess

900 filter group X-X main axis