WO2021005507A1

WO2021005507A1 - Air filter intended for i.c. engines and having a safety cartridge

Info

Publication number: WO2021005507A1
Application number: PCT/IB2020/056379
Authority: WO
Inventors: Nazzareno BERTUCCI; Umberto Cornaglia; Mauro GOTELLI; Paolo Vitagliani
Original assignee: Officine Metallurgiche G. Cornaglia S.P.A.
Priority date: 2019-07-08
Filing date: 2020-07-07
Publication date: 2021-01-14
Also published as: IT201900011187A1; BR112022000326A2; EP3997323A1; EP3997323B1; TR201922235A2; EP3997323C0

Abstract

An air filter (11) for I.C. engines, comprising a housing (13), provided with a removable lid (15), in which a compartment (21) is provided, in which a main filter element (17) and a secondary filter element (19) are received, said filter elements (17, 19) being individually replaceable, wherein the secondary filter element (19) defines a corresponding pocket (23) in which the main filter element (17) is received.

Description

AIR FILTER INTENDED FOR I.C. ENGINES AND HAVING A SAFETY CARTRIDGE

The invention relates to an air filter intended for I.C. engines and having a safety cartridge. More particularly, the invention relates to an air filter intended for heavy use, for example in air intake circuits of I.C. engines mounted on agricultural machines, earth-moving machines, industrial vehicles and the like.

In the field of I.C. engines for heavy use, for example for use in the fields of agriculture and earth-moving machinery, air filter having a main filter element and a secondary filter element, or safety element, are known, the secondary filter element being provided downstream of the main filter element in the direction of air flow from the outside environment to the engine. These filter elements must be replaced when clogged and, for this reason, they are also called air filter cartridges. The function of the safety cartridge is to prevent excessively dirty air from entering the part of the intake circuit located downstream of the filter, with the consequent risk of damage to the engine. This circumstance can occur, for example, as a result of the breakage of the filter material of the main cartridge, or during the replacement of the main cartridge, due to the unwanted entry of material into the filter, or even when, by mistake or forgetfulness, the main cartridge is not mounted.

WO03084641 (A2) describes an example of an air filter intended for I.C. engines and having a safety cartridge.

An undesirable effect of the safety cartridge is that the filter has larger overall dimensions. The safety cartridge according to prior art is in fact made up of a pack of filter material generally made in the form of a panel or tray, and, being located downstream of the main cartridge, it determines a consequent increase in the filter size.

Another undesirable effect due to the presence of the safety cartridge is a reduction in the filter flow rate. This undesirable effect is more evident when the service life of the safety cartridge is extended, because the safety cartridge is generally replaced or cleaned less frequently than the main one. An exhausted safety cartridge which is exhausted due to clogging inevitably causes a decrease in the filter flow rate.

A not least drawback of prior art lies in the fact that the safety cartridge, because of its arrangement inside the filter, downstream of the main cartridge, is difficult to extract and reposition. For this reason, users tend to rarely replace the safety cartridge, or even remove it, without replacing it with a new one, for ease of maintenance. Obviously, an air filter deprived of the safety cartridge is exposed to the aforementioned risks of unwanted entry of material into the intake ducts of an I.C. engine associated with the filter.

The main object of the invention is to overcome the drawbacks of prior art, in particular those mentioned above, by providing an improved air filter intended for I.C. engines and having a safety cartridge.

Another object of the invention is to provide an air filter for I.C. engines that is compact and has high flow rate and high filtering capacity.

A further object of the invention is to provide an air filter that is intended for I.C. engines, has a main cartridge and a safety cartridge, and is easy to maintain and therefore allows quick and safe replacement of both cartridges.

Yet another object of the invention is to provide and air filter that has a safety cartridge and discourages the elimination of the safety cartridge by users.

Not the least object of the invention is to provide an air filter of the aforementioned type that can be industrially manufactured in a cost-effective manner.

These and other objects are achieved by the invention as claimed in the appended claims.

The air filter for I.C. engines mainly comprises a housing, a removable lid and a pair of filter elements. The pair of filter elements are housed in a compartment defined within the housing and comprise a main filter element, or main cartridge, and a secondary filter element, or safety cartridge. Within the housing and in the direction of the air flow passing through the filter, the main cartridge is functionally arranged upstream of the safety cartridge so that the air flow passing through the filter first passes through said main cartridge.

The function of the main cartridge is to separate impurities from the flow of dirty air passing through the filter, during operation of the engine with which the filter is associated. The air that comes from the outside environment and has passed through the main cartridge is therefore essentially so-called clean air, i.e. air that can be introduced into the combustion chambers of an I.C. engine. The main cartridge, when its service life is exhausted, can be replaced with a new one by opening the filter lid and removing the exhausted cartridge from the housing compartment in which it is housed. The function of the safety cartridge is to prevent entry of impurities into the intake circuit of the I.C. motor, in particular during replacement of the main filter element, or in case of accidental breakage of the filtering material of said main filter element.

These cartridges are individually removable, i.e. they can be removed individually and replaced independently of each other when necessary.

According to the invention, preferably, the main filter element has a higher filtering capacity than the secondary filter element. Even more preferably, the filtering capacity of the main filter element is at least 50% higher than that of the secondary filter element.

Advantageously, according to the invention, the safety cartridge defines a corresponding bag or pocket, in which the main cartridge is received. According to the invention, therefore, the safety cartridge surrounds, preferably almost entirely, the main cartridge, leaving only one side of the main cartridge free in order to allow air entry.

In a preferred embodiment of the invention, the main cartridge and the safety cartridge have a substantially complementary shape and the inner pocket defined in the safety cartridge is preferably sized in such a way as to minimize the distance between the outer surface of the walls of the main cartridge and the inner surface of the walls of the pocket. Even more preferably, the inner pocket defined in the safety cartridge is sized so that the outer surface of the walls of the main cartridge is in contact with the inner surface of the walls of the pocket by at least 50% of the outer surface of the walls of said main cartridge. Even more preferably, said percentage is at least 70%. Advantageously, thanks to this measure, the main cartridge is housed in the pocket defined in the safety cartridge, without appreciable increase in the overall volume of the pair of filter elements. In the most preferred embodiment providing for contact between the walls of the two cartridges, this increase in volume is essentially determined by the thickness of the walls of the safety cartridge.

Preferably, according to the invention, the safety cartridge comprises a support structure, preferably having a prismatic shape, for example a parallelepiped or cylindrical shape, in which a side wall and a pair of opposite bases are defined. The side wall and a first one of the opposite bases are preferably both provided also with openings for air passage. The support structure is further coated, preferably inside, at least at said openings, with a layer of filter material, made of a synthetic material or a cellulose-based material.

Advantageously, according to the invention, the walls of the support structure are preferably made with a reduced thickness, comprised between 1.5 and 5.0 mm. Even more preferably, the thickness of the walls of the support structure is about 2.5 mm. In addition, the thickness of the walls of the safety cartridge is preferably approximately constant over the entire body of the cartridge. The thickness of the layer of filter material is preferably in the order of millimeters, and even more preferably, it is between 0.3 and 0.9 mm. The second opposite base of the safety cartridge is preferably open, for allowing easy passage of the main cartridge, which, in use, is housed within the secondary cartridge of the filter.

In a preferred embodiment of the invention, the main cartridge and the safety cartridge have a substantially prismatic shape, with opposite bases that are substantially rectangular and parallel to each other and have different areas, whereby the side walls are slightly tapered from the major base towards the minor base.

Advantageously, according to the invention, the provision of the safety cartridge within the filter according to the invention guarantees the presence of a safety filter layer, which retains any impurities and foreign bodies, preventing them from penetrating into the intake circuit of the engine. Advantageously, still according to the invention, the safety cartridge does not lead to an appreciable increase in the size of the filter, since it is substantially configured as a pocket in which the main cartridge is housed.

According to the invention, the support structure is preferably made of plastic, for example a plastic mesh, with large windows for air passage. The support structure therefore confers a certain rigidity to the safety cartridge, which can therefore be advantageously inserted into and removed from the housing with ease and without risk of breakage and consequent unwanted entry of material into the filter.

The support structure of the safety cartridge preferably includes a molded one-piece plastic grid extending along the side walls and one of the bases of the safety cartridge. This grid also defines, preferably, a perimeter portion, radially projecting towards the outside of the safety cartridge, around the open base, and defining a stiffening core for a corresponding sealing gasket of the safety cartridge, for example made of rubber or polyurethane foam. Preferably, in addition, the support structure and the gasket are co-molded, or the gasket can be attached, or applied, in a separate processing step, on the projecting portion of the support structure.

In addition, according to the invention, the gasket of the safety cartridge preferably has a cross-section having substantially the shape of an overturned “U” and capable of cooperating with a first inner perimeter edge provided in the filter housing. This cooperation determines the correct centering of the safety cartridge inside the compartment of the filter housing and an adequate airtight seal between the gasket and said first edge of the housing, thus preventing unwanted entry of air from the outside environment directly into the compartment of the housing, by-passing the main and safety cartridges.

Still according to the invention, the safety cartridge preferably includes a pair of inner side guides cooperating with a pair of outer side projections provided in the main cartridge. The outer side projections are preferably defined at a bottom closing one of the basis of the main cartridge. The guides provided in the safety cartridge are preferably provided at the bottom of the cartridge and by cooperating with the side projections of the main cartridge, they are advantageously adapted to guide the main cartridge within the pocket defined in the safety cartridge, during replacement of the main cartridge. Advantageously, thanks to this measure, the centering of the main cartridge relative to the safety cartridge is optimal and the replacement of the main cartridge can be carried out easily and without removing the safety cartridge. In a preferred embodiment of the invention, the guides are defined by pairs of inclined planes converging towards the bottom of the safety cartridge and defining a frustoconical inlet surface for the projections of the main cartridge. Preferably, the angle of the inclined planes is such as to define an inlet surface with a conicity between 45° and 90° and, even more preferably, about 60°.

The filter according to the invention provides that, preferably, both the main cartridge and the safety cartridge each include a corresponding perimeter sealing gasket. In addition, according to a preferred embodiment of the invention, said gaskets cooperate with each other to define the corresponding hermetic seal when these cartridges are housed in the filter housing and the lid has been closed. According to a particular embodiment of the invention, the safety cartridge includes a perimeter edge surrounding the open base and having a sealing gasket. This sealing gasket advantageously defines a distal abutment surface relative to the safety cartridge, for a corresponding abutment surface provided on the sealing gasket of the main cartridge.

Preferably, when the lid is closed on the housing, the sealing gasket of the safety cartridge is in contact, on one side, with a perimeter edge surrounding the housing and, on the other side, with the sealing gasket of the main cartridge, whereas the sealing gasket of the main cartridge, when the lid is closed on the housing, is in contact with a perimeter edge surrounding the housing and a corresponding perimeter edge surrounding the lid. In this way, the hermetic seal is advantageously guaranteed even without the safety cartridge. In addition, said gaskets are preferably compressed between these perimeter edges when the lid is closed with known means such as screws or hooks.

Advantageously, according to a particular embodiment of the invention, the sealing gasket of the main cartridge preferably comprises at least one centering seat or projection, provided for receiving a corresponding centering projection or seat provided on the lid or on the housing, when the main filter element is within the housing and the housing is closed by the lid.

The housing of the filter according to the invention preferably comprises a side wall and a pair of opposite bases. A first one of said bases is open and can be closed by the filter lid, and a second one of said bases, opposite to the first base, is provided with an outlet opening for clean air.

In addition, the filter lid preferably includes a plurality of separators to separate larger impurities from the air flow passing through the lid.

According to a preferred embodiment of the invention, the main cartridge includes a pair of packs of pleated paper, arranged in a "V"-like configuration, such as to define a central passage for the entry of air flowing out of the center of the main cartridge and towards the periphery through the pleats of the paper. Brief Description of Drawings

Some preferred embodiments of the invention will be described by way of non-limiting examples with reference to the annexed drawings, in which:

Fig. 1

Fig.1 is an exploded view of the filter according to a preferred embodiment of the invention;

Fig. 2

Fig.2 is a perspective view of the housing of the filter of Fig.1;

Fig. 3

Fig.3 is a longitudinal section of the housing of the filter of Fig.1;

Fig. 4

Fig.4 is a longitudinal section of the filter of Fig.1;

Fig. 5

Fig.5 is a perspective view of the safety cartridge of the filter of Fig.1;

Fig. 6

Fig.6 is a lateral plan view of the safety cartridge of Fig.5

Fig. 7

Fig.7 is a longitudinal section taken along the plane VII-VII of the safety cartridge of Fig.5;

Fig. 8

Fig.8 is a perspective view of the main cartridge of the filter of Fig.1;

Fig. 9

Fig.9 is a bottom view of the main cartridge of Fig.8;

Fig. 10

Fig.10 is a longitudinal section of the main cartridge of Fig.8;

Fig. 11

Fig.11 is an enlarged view of a detail of Fig.10.

Description of Some Preferred Embodiments

Referring to Fig.1, an air filter 11 for I.C. engines made in accordance with the invention comprises a housing 13, a removable lid 15 and a pair of

filter elements

17,19 housed within a compartment 21 defined within the housing 13. The pair of

filter elements

17,19 comprise a main filter element, or main cartridge 17, and a secondary filter element, or safety cartridge 19.

The safety cartridge 19 defines a corresponding pocket 23, in which, during use, the main cartridge 17 is received. When the pair of

cartridges

17,19 are installed within the filter 11, the safety cartridge 19 therefore surrounds almost entirely the main cartridge 17, leaving only the inlet face 25 of said main cartridge 17 substantially free in order to allow entry of the air coming from the lid 15.

In the illustrated embodiment, the safety cartridge 19 comprises a support structure 27 in which a side wall 29 and a pair of

opposite bases

31,33 are defined. The side wall 29 and a first one 31 of the

opposite bases

31,33 are provided with openings 35 for the passage of air therethrough. The support structure 27 is also coated inside with a layer of filter material 28, for example a synthetic material or a cellulose-based material. In the illustrated embodiment, the wall of the support structure 27 has a substantially constant thickness of about 2.5 mm. In the illustrated embodiment, the thickness of the filter material 28 is about 0.5 mm. The safety cartridge 19 is further designed so as to be substantially in contact with the outer surface of the main cartridge 17 and therefore, in total, the presence of the safety cartridge 19 determines a minimum increase in the volume of the main cartridge 17.

The second opposite base 33 of the safety cartridge 19 is preferably designed completely open, for allowing easy passage of the main cartridge 17, which, in use, is housed within the safety cartridge 19, within the pocket 23 defined therein.

Referring to Figs.5, 6 and 7, in the illustrated embodiment, the support structure 27 is made of plastics and is provided, on the base 31 and on the larger opposite faces 29a,29b, with large openings 35 for air passage. The smaller opposite lateral faces 29c,29d of the support structure 27, instead, have no openings and comprise a rectilinear axial projection 37. Referring also to Fig.3, said projection 37 advantageously cooperates with a corresponding longitudinal guide 39 provided within the housing 13 of the filter in order to keep the safety cartridge 19 in its correct position within the compartment 21 defined within the filter 11. In the illustrated embodiment, the guide 39 is provided within the housing 13 at the smaller opposite faces of the side wall 69.

In the illustrated embodiment, the base 33 of the safety cartridge 19 defines an opening 41which leaves said base 33 substantially open. The opening 41 provided at the base 33 of the safety cartridge 19 is surrounded by a sealing gasket 43, made, for example, of rubber or polyurethane foam and preferably co-molded with the support structure 27.

The support structure 27 confers a certain rigidity to the safety cartridge 19, which can therefore be advantageously inserted into and removed from the housing 13 with ease and without risk of breakage and consequent unwanted entry of material into the filter.

Referring also to Fig.8, and still with reference to the illustrated embodiment, the support structure 27 comprises a perimeter portion 44 radially projecting towards the outside of the safety cartridge 19, around the opening 41 of the base 33, and defining a stiffening core for a corresponding sealing gasket 43 preferably co-molded with said support structure 27.

Still according to the invention, the safety cartridge 19 comprises a pair of inner side guides 45 arranged along the opposite faces 29c,29d and cooperating with a pair of outer side projections 47 provided in the main cartridge 17. Said side projections 47 are defined at a bottom 49, for example made of rubber or polyurethane foam, which closes the base 51 of the main cartridge 17.

In the preferred embodiment of the invention illustrated herein, the inner side guides 45 are defined by pairs of

inclined planes

45a,45b converging towards the bottom of the safety cartridge 19 and defining a frustoconical inlet surface 45c. In the shown example, the angle between the inclined planes is such as to define an inlet surface 45c having a conicity α of about 60°.

Referring again also to Fig.1, the frustoconical inlet surface 45c advantageously cooperates with a pair of projections 47 provided in the main cartridge 17. The guides 45 provided within the safety cartridge 19 can, by cooperating with said side projections 47, advantageously guide the main cartridge 17 within the pocket 23, defined by the safety cartridge 19, during replacement of the main cartridge 17. Advantageously, thanks to this measure, the centering of the main cartridge 17 relative to the safety cartridge 19 is optimal and the replacement of the main cartridge 17 can be carried out easily and without removing the safety cartridge 19.

Referring to Figgs.10 and 11, the main cartridge 17 includes a pair of packs of pleated paper 50, arranged in a "V"-like configuration, so as to define a central passage 53 for the entry of air flowing out of the center of the main cartridge 17 and towards the periphery through the pleats of the paper (arrows F1). The base 55 of the main cartridge 17 is open for air entry and is surrounded by a gasket 57 made of rubber or polyurethane foam. Preferably, the gasket 57 comprises a stiffening core 59 made of a plastic material.

As can be better appreciated in Fig.4, according to the illustrated embodiment of the invention, the

gaskets

43 and 57 cooperate with each other to define the corresponding hermetic seal when the

cartridges

17 and 19 are received within the housing 13 of the filter and lid 15 is closed.

The sealing gasket 43 of the safety cartridge 19 advantageously defines an abutment surface 61 distal relative to the support structure 27 of the safety cartridge 19, for a corresponding abutment surface 63 provided on the sealing gasket 57 of the main cartridge 17.

In this embodiment of the invention, when the lid 15 is closed on the hosuing 13, the sealing gasket 43 of the safety cartridge 19 is in contact, on one side, with a perimeter edge surrounding the housing 13, and, on the opposite side, with the sealing gasket 57 of the main cartridge 17, whereas the sealing gasket 57 of the main cartridge 17, when the lid 15 is closed on the housing 13, is in contact with a perimeter edge surrounding the housing 13 as well as with a corresponding perimeter edge surrounding the lid 15. In this way, the hermetic seal is advantageously guaranteed even without the safety cartridge 19. In addition, said

gaskets

43, 57 are preferably compressed between said perimeter edges when the lid 15 is closed with known means such as screws or hooks.

As can be better appreciated in Figs.2 and 9, in the illustrated embodiment, the sealing gasket 57 of the main cartridge 17 comprises a plurality of centering seats 65 provided for receiving corresponding centering projections 67 provided on the housing 13, when the main cartridge 17 is within the housing 13 and the housing 13 is closed by the lid 15.

In the illustrated embodiment, the housing 13 of the filter 11 according to the invention comprises a side wall 69 and a pair of

opposite bases

71,73. A first one 71 of said bases is open and can be closed by the lid 15 of the filter, and a second one 73 of said bases, opposite to the first one, is provided with an outlet opening 75 for clean air.

As can be better appreciated in Figs. 1 and 4, the lid 15 of the filter comprises a plurality of cyclone separators or turbulators 77 for separating larger impurities from the air flow that passes through the lid 15, coming from the outside environment, and is directed to the main cartridge 17 at the central passage 53.

Referring again in particular to Fig.1, the function of the main cartridge 17 is to separate impurities from the flow of dirty air passing through the filter 11, during operation of the engine with which the filter is associated. The air that comes from the outside environment and has passed through the main cartridge 17 is therefore essentially so-called clean air, i.e. air that can be introduced into the combustion chambers of an I.C. engine. The main cartridge 17, when its service life is exhausted, can be replaced with a new one by opening the filter lid 15 and removing the exhausted cartridge from the compartment in which it is housed. The function of the safety cartridge 19 is to prevent entry of impurities into the intake circuit of the I.C. motor, in particular during replacement of the main filter element 17, or in case of accidental breakage of the filtering material of said main filter element 17. The

aforesaid cartridges

17,19 are individually removable, i.e. they can be removed individually and replaced independently of each other when necessary.

The invention as described and illustrated is susceptible of numerous changes and modifications falling within the same inventive principle.

Claims

An air filter (11) for I.C. engines, comprising a housing (13), provided with a removable lid (15), in which a compartment (21) is provided, in which a main filter element (17) and a secondary filter element (19) are received, said filter elements (17,19) being individually replaceable, characterized in that the secondary filter element (19) defines a corresponding pocket (23) in which the main filter element (17) is received.
The filter according to claim 1, wherein the secondary filter element (19) comprises a support structure (27), in which a side wall (29) and a pair of opposite bases (31,33) are defined, the side wall (29) and a first one (31) of the opposite bases being provided with openings (35) and being coated, at least at said openings (35), with a layer of filter material (28), and wherein the second opposite base (33) is open for allowing passage of the main filter element (17).
The filter according to claim 1 or 2, wherein the secondary filter element (19) comprises a pair of inner side guides (45) cooperating with a pair of outer side projections (47) provided in the main filter element (17) and adapted to guide the main filter element (17) within the secondary filter element (19).
The filter according to claim 1 or 2 or 3, wherein the main filter element (17) and the secondary filter element (19) comprise a corresponding annular sealing gasket (57,43), and wherein said gaskets cooperate with each other in order to define a corresponding hermetic sealing when said main and secondary filter elements (17,19) are received in the housing (13) and the lid (15) is closed.
The filter according to claim 4, wherein the sealing gasket (43) of the secondary filter element (19) defines an abutment surface (61) for a corresponding abutment surface (63) defined by the sealing gasket (57) of the main filter element (17).
The filter according to any of the preceding claims, wherein the housing (13) comprises a side wall (69) and a pair of opposite bases (71,73), a first base (71) being open and closeable by the lid (15), and a second base (73) being provided with an outlet opening (75) for clean air.
7. The filter according to any of the preceding claims, wherein the main filter element (17) and the secondary filter element (19) have a substantially complementary shape and the inner pocket (23) defined in the secondary filter element (19) is sized so as to minimize the distance between the outer surface of the main filter element (17) and the inner surface of the walls of the pocket (23).
The filter according to claim 7, wherein the inner pocket (23) defined in the secondary filter element (19) is sized so that the outer surface of the walls of the main filter element (17) is in contact with the inner surface of the walls of the pocket (23) by at least 50% of the outer surface of the walls of said main filter element.
The filter according to claim 8, wherein the inner and outer walls of the two filter elements, the main one (17) and the secondary one (19), are in mutual contact by at least 70% of their surface so as to minimize the increase in the volume of the main filter element (17), caused by the presence of the secondary filter element (19).
The filter according to any of the preceding claims, wherein the main filter element (17) comprises a sealing gasket (57) having at least one centering seat (65) for receiving a corresponding centering projection (67) provided on the lid (15) or on the housing (13) when the main filter element (17) is located within the housing and the housing is closed by the lid.