ITRE20090086A1 - FILTER FOR ENDOTHERMIC ENGINES - Google Patents

Description

DESCRIPTION

"FILTER FOR ENDOTHERMIC ENGINES"

The present invention relates to a filter for internal combustion engines, especially for internal combustion engines which are mounted on board vehicles.

The features of the invention are mainly applied to an air filter adapted to be connected to the intake of an internal combustion engine, but can also be applied to filters for different fluids, for example to an exhaust gas filter or to a fuel filter. .

As is known, air filters generally comprise a rigid outer casing, normally called a filter box, which is equipped with an inlet for the air to be filtered and an outlet for the filtered air.

On board a vehicle, the filter box is normally placed inside the engine compartment, where it is associated with a first duct suitable for connecting the inlet with an air intake in the bonnet or in the front part of the vehicle, and to a second conduit adapted to connect the outlet with the intake manifold of the engine.

The filter box houses a filter cartridge designed to filter the air flowing from the inlet to the outlet.

The filter cartridge must have good filtering efficiency, without causing excessive pressure drops, and must have a sufficiently high accumulation capacity, so as not to be replaced too frequently.

The filtering cartridge can be of various construction types, on which the geometric and dimensional characteristics of the filter box often also depend.

In particular, filter cartridges are known which include filtering septa shaped as rectangular sheets or as toroidal bodies, possibly pleated to increase the filtering surface and accumulation capacity.

These filter cartridges have quite large dimensions and therefore have the drawback of having to be housed inside bulky filter boxes, which take up a lot of space inside the engine compartment.

Filter cartridges are also known which include a slightly conical, tubular-shaped filter septum, which is suitable for being inserted directly into the engine intake duct.

In this case, the filter box is actually made up of a section of the intake duct.

These tubular-shaped filter septa can be made from a non-woven felt or a more traditional pleated septum.

The tubular-shaped filtering septa have the drawback of increasing the pressure drops, due to the small space between the septum and the duct in which it is contained, and of having an accumulation capacity (and therefore a useful life). limited, due to the small filtering surface offered.

Finally, so-called multi-septa filter cartridges are known, which comprise a plurality of tubular-shaped filter septa which are arranged aligned in parallel rows, so as to form a bundle.

Said tubular filtering septa are closed at one end by a continuous wall support flange, while they are supported at the opposite end by a perforated support flange, which is provided with a plurality of openings which are individually aligned with the cavity. of a respective filter media.

The multi-septa filter cartridges are housed inside a filter box, where the tubular filter septa are generally crossed in parallel by the air to be filtered.

According to the embodiment, the air to be filtered can pass through the tubular filtering septa from the inside to the outside or from the outside to the inside.

Multiset filter cartridges have the advantage of guaranteeing rather low pressure drops.

A drawback of the multi-septa filter cartridges is represented by the early clogging of the tubular filtering septa, caused by rather coarse particles that are sometimes carried by the air flow.

An object of the present invention is to solve the aforementioned drawback of the multi-septic filter cartridges of the known art.

A further purpose of the invention is to achieve this goal in the context of a simple, rational and low-cost solution.

These purposes are achieved by the characteristics of the invention reported in independent claim 1. The dependent claims outline preferred and / or particularly advantageous aspects of the invention.

The invention makes available a filter for endothermic engines, which generically comprises an external casing provided with at least one inlet for a fluid to be filtered and an outlet for the filtered fluid, and a filter cartridge placed inside said casing.

Said filter cartridge includes a plurality of tubular-shaped filtering septa, which are able to be crossed by the fluid flowing from the inlet to the outlet of the external casing.

Said tubular filtering septa can be made from a non-woven fabric of polymeric fibers, for example of polypropylene, which can be obtained through any known process, preferably by melt-blown.

According to the invention, the filter cartridge comprises a further tubular pre-filtration septum, which externally wraps the plurality of tubular filtering septa, so as to be crossed by the fluid upstream of said tubular filtering septa.

In this way, the pre-filtration tubular septum is able to retain the coarser particles transported by the fluid, which otherwise could rapidly clog the downstream tubular filtering septums.

The pre-filtration tubular septum can be made from a non-woven fabric of polymeric fibers, for example of polypropylene or polyester, which can be obtained through any known process.

The pre-filtration tubular septum generally has a higher porosity than that of the tubular filter septums.

The pre-filtration tubular septum can be made in such a way as to have both ends open.

In this case, each end is preferably fixed to a respective support flange, to delimit the space in which the tubular filtering septa are contained.

A preferred embodiment, however, provides that the tubular pre-filtration septum is made in such a way as to have an open end and an opposite closed end, so as to substantially assume the shape of a bag or a cup suitable for accommodating the filtering septa tubular inside.

This closure can be obtained by flattening and joining the side wall of the tubular pre-filtration septum, at said end.

Similarly, the tubular filtering septa can be made in such a way as to have both ends open.

In this case, a first end of each tubular filtering septum is preferably fixed to a support flange, which is provided with at least one through hole aligned with the internal cavity of said tubular filtering septum; while the opposite end of each tubular filter partition is closed by a second continuous wall support flange.

A preferred embodiment, however, provides that each tubular filtering septum is made in such a way as to have an open end and the opposite closed end, so as to substantially assume the shape of an elongated cap.

This closure can be obtained by flattening and joining the side wall of the tubular filtering septum, at said end.

Also in this case, the open end of each tubular filtering septum is preferably fixed to a support flange having at least one through hole aligned with the internal cavity of the tubular filtering septum; but the opposite closed end can be left free.

Further features and advantages of the invention will become evident from reading the following description provided by way of non-limiting example, with the aid of the figures illustrated in the attached tables.

Figure 1 is a plan view of an air filter according to the invention.

Figure 2 is the orthogonal projection of the view of Figure 1.

Figure 3 is the section III-III of Figure 2.

Figure 4 is the section IV-IV of Figure 3.

Figure 5 is the V-V section of Figure 3 rotated and shown on an enlarged scale.

Figure 6 is Figure 2 shown during the insertion / extraction of the filter cartridge.

Figure 7 is the section of Figure 3 relating to an air filter according to an alternative embodiment.

Figure 8 is the section VIII-VIII of figure 7.

The air filter 1 illustrated in Figures 1 and 2 comprises a rigid outer casing 2, which will be referred to simply as the filter box hereinafter.

The filter box 2 can be made of bent sheet metal or plastic material.

The filter box 2 includes a central body 20 which communicates with an inlet 21 for the air to be filtered and with an outlet 22 for the filtered air.

The inlet 21 and the outlet 22 are aligned along a longitudinal axis X of the filter box 2.

The central body 20 comprises an openable cover 23, for the insertion and extraction of a removable filter cartridge 3 (see for example Fig. 6), which is adapted to be inside the filter box 2 to filter the air flowing from inlet 21 to outlet 22.

As shown in Figure 3, the filter cartridge 3 comprises a plurality of filtering septa 30 of tubular shape arranged parallel to each other, which are able to be crossed by the air to be filtered, to retain any impurities present therein. The filter cartridge 3 is inserted inside the central body 20 of the filter box 2, so that said tubular filter septa 30 are parallel to the longitudinal axis X.

The tubular filter septa 30 can be made from a non-woven fabric of polymeric fibers, for example of polypropylene, which can be obtained through any known process, preferably by melt-blown.

The tubular filtering septa 30 are generally rather rigid, and are therefore able to normally maintain their tubular shape and their rectilinear development.

In the illustrated examples, the tubular filter septa 30 have all the same dimensions.

Each tubular filtering septum 30 can be coupled to a respective support candle, consisting for example of a perforated plastic or metal tube, which is coaxially inserted inside or outside the relative tubular filtering septum 30. The filter box 2 is intended to be housed inside the engine compartment of a vehicle (not shown), with the inlet 21 connected to an air intake that can be obtained on the bonnet or in the front part of the engine compartment, and the outlet 22 connected with the intake manifold of the vehicle's internal combustion engine.

As shown in Figure 5, the central body 20 of the filter box 2 is shaped in such a way as to make available a pocket whose cross section, carried out according to a plane orthogonal to the axis of the tubular filter septa 30, is rather wide and relatively thin.

The tubular filter septa 30 of the filter cartridge 3 are inserted in the filter box 2 side by side, so that the pocket is occupied by a single row of tubular filter septa 30.

Alternatively, the pocket could have a much wider cross-section, so as to accommodate a filter cartridge 3 equipped with tubular filter septa 30 arranged for several superimposed rows to form a bundle.

In the example shown in Figures 1 to 5, the filtering septa 30 are made so as to have both ends open.

The ends of the tubular filtering septa 30 are fixed to a respective support flange 31 and 32.

Said support flanges 31 and 32 are individually adapted to connect the tubular filtering septa 30 to each other, to make the filtering cartridge 3 a single body.

The tubular filter septa 30 can be individually fixed to each support flange 31 and 32 by gluing, by means of an interlocking coupling and disengagement system, or by any other suitable system.

The support flanges 31 and 32 can be made of plastic or metal material.

The support flange 31 comprises a plurality of through holes 33, equal in number to the number of tubular filtering septa 30, each of which is aligned with the cavity of a respective tubular filtering septum 30.

The support flange 32, on the other hand, has a continuous wall, to close the opposite end of each tubular filter partition 30.

As shown in Figure 5, the filtering cartridge 3 further comprises a filtering membrane 35 shaped like a tubular sleeve, which externally and coaxially wraps all the tubular filtering septa 30 of the cartridge 3.

The filter membrane 35 is made in such a way as to have both ends open.

The ends of the filter membrane 35 are closed by the support flanges 31 and 32, so as to delimit an internal space in which all the tubular filter septa 30 are contained.

The filter membrane 35 can be fixed to the support flanges 31 and 32 by gluing, by means of an interlocking coupling and disengagement system, or by any other suitable system.

The filter membrane 35 can be made from a non-woven fabric of polymeric fibers, for example of polypropylene or polyester, which can be obtained through any known process.

The filter membrane 35 generally has a higher porosity than that of the tubular filter septa 30.

The filter cartridge 3 is placed inside the filter box 2 with the support flange 31 facing the outlet 22 and the support flange 32 facing the inlet 21.

As illustrated in Figures 3 and 4, the support flange 31 is able to occupy entirely the cross section of the filter box 2, so as to divide its internal volume into two distinct chambers, of which a first chamber 25 communicating with the inlet 21 , and a second chamber 26 communicating with exit 22.

The support flange 32, on the other hand, has recesses (see Figs. 4 and 5), which define lateral passages 34 inside the filter box 2, which are external to the cavity of the tubular filter septa 30.

Thanks to this solution, the air to be filtered that arrives in the first chamber 25 cannot axially enter the tubular filter septa 30 which are closed by the support flange 32, and is therefore forced to flow through the side passages 34.

Since the support flange 31 completely occupies the passage section of the filter box 2, the air to be filtered is forced to radially cross the filter membrane 35 from the outside to the inside.

Once inside the filter membrane 35, the air is then forced to radially cross the tubular filtering septa 30, also from the outside to the inside.

The filtered air finally flows axially along the tubular filter septa 30 and passes through the through holes 33 of the support flange 31, to reach the second chamber 26 and the outlet 22.

In practice, the tubular filter septa 30 are globally crossed in parallel by the air to be filtered, but in series with respect to the filter membrane 35, which is placed upstream with respect to the direction of the air flow.

The filtering membrane 35, which is crossed first, is therefore suitable for carrying out the pre-filtration of the air, while the tubular filtering septa 30, which are crossed for seconds, are able to perform the final filtration.

Pre-filtration is useful for retaining the coarser particles upstream, and to prevent the tubular filtering septa 30 from becoming clogged too quickly, thereby increasing the useful life of the filter cartridge 3.

Figures 7 and 8 illustrate an air filter 1 which differs from the previous one in that the filter cartridge 3 comprises tubular filter septa 30 ', each of which is made in such a way as to have an open end and an opposite closed end , which essentially gives it the shape of a narrow, elongated hood.

Said closure is preferably obtained by squeezing the side wall of each tubular filtering septum 30 'at said end, so as to flatten it until two opposite portions of the side wall are brought into mutual contact, to close the passage.

The portions in contact are then joined together, preferably by heat sealing, ie by at least partial melting of the septum material, pressure and subsequent solidification.

Alternatively, the portions in contact can be joined by gluing or by other known systems.

If possible, each 30 'tubular filter septum could be made directly in the form of a container closed at the bottom.

The open ends of the 30 'tubular filter media are fixed to a single support flange 31, which is suitable for connecting all the 30' tubular filter media to each other.

The closed ends of the 30 'tubular filter media are instead left free.

The tubular filter media 30 'can be individually fixed to the support flange 31 by gluing, by means of an interlocking coupling and disengagement system, or by any other suitable system.

The support flange 31 can be made of plastic or metal material.

The support flange 31 comprises a plurality of through holes 33, equal in number to the number of tubular filter septa 30 ', each of which is aligned with the cavity of a respective tubular filter element 30'.

The filter cartridge 3 also includes a filter membrane 35 'shaped like a bag or a glass, whose mouth is closed by the support flange 31, so as to delimit an internal space in which all the tubular filtering septa 30' are contained.

The filter membrane 35 'can be fixed to the support flange 31 by gluing, by means of an interlocking coupling and disengagement system, or by any other suitable system.

The filter membrane 35 'can be made from a non-woven fabric of polymeric fibers, for example of polypropylene or polyester, which can be obtained through any known process.

The 35 'filter membrane generally has a higher porosity than that of the 30' tubular filter media.

In practice, the 35 'filter membrane is made as a tubular body designed to externally wrap the entire plurality of 30' tubular filter septa.

Said tubular body has an open end and an opposite closed end, which gives it the aforementioned shape of a bag or glass.

This closure is preferably obtained by squeezing the side wall of the tubular filter membrane 35 'at said end, so as to flatten it until two opposite portions of the side wall itself are in mutual contact, to close the passage.

The portions in contact are then joined together, preferably by heat sealing, i.e. by at least partial melting of the septum material, pressure and subsequent solidification.

Alternatively, the portions in contact can be joined by gluing or by other known systems.

If possible, the 35 'filter membrane can be directly made in the form of a container closed at the bottom, such as a bag or a glass.

The filter cartridge 3 is inserted in the filter box with the support flange 31 facing the outlet 22.

As shown in figure 8, the support flange 31 is shaped to completely occupy the passage section of the filter box, dividing the internal volume into the chambers 25 and 26 communicating respectively with the inlet 21 and the outlet 22.

In this way, the air to be filtered that reaches the first chamber 25 is forced to cross the filter membrane 35 'from the outside to the inside.

Once inside the 35 'filter membrane, the air is then forced to pass through the 30' tubular filter media, also from the outside to the inside.

The filtered air finally flows axially along the tubular filtering septa 30 'and passes through the through holes 33 of the support flange 31, to reach the outlet 22.

In practice, the 30 'tubular filter septa are crossed in parallel, but in series with respect to the 35' filter membrane, which is placed upstream with respect to the direction of the air flow, in order to carry out the pre-filtration.

Obviously, to the air filter 1 described above, a technician in the field will be able to make numerous modifications of a technical application nature, without thereby departing from the scope of the invention as claimed below.

Claims (14)

CLAIMS 1. Filter for endothermic engines, comprising an external casing (2) provided with at least one inlet (21) for a fluid to be filtered and an outlet (22) for the filtered fluid, and a filter cartridge (3) placed inside of said casing (2), which comprises a plurality of tubular filtering septa (30, 30 ') able to be crossed by the fluid flowing from the inlet (21) to the outlet (22) of the external casing (2) , characterized in that said filter cartridge (3) comprises a further tubular pre-filtration septum (35, 35 '), which externally wraps the plurality of tubular filtering septa (30, 30'), so as to be traversed by the fluid a upstream of said tubular filtering septa (30, 30 '). 2. Filter according to claim 1, characterized by the fact that said further pre-filtration tubular septum (35, 35 ') is made in such a way as to have at least one open end. 3. Filter according to claim 2, characterized in that said open end of the pre-filtration tubular septum (35, 35 ') is fixed to a support flange (31), which is adapted to delimit a volume containing the tubular filter media (30, 30 '). 4. Filter according to claim 3, characterized in that said further pre-filtration tubular septum (35) is made so that the opposite end is also open, said opposite end being closed by a second support flange (32), the which is suitable for delimiting the volume in which the tubular filtering septa (30) are contained. 5. Filter according to claim 2, characterized by the fact that said further pre-filtration tubular septum (35 ') is made so that the opposite end is closed. 6. Filter according to claim 5, characterized by the fact that said closed end is obtained by flattening and joining the side wall of the tubular pre-filtration septum (35 '). 7. Filter according to claim 1, characterized by the fact that each tubular filtering septum (30, 30 ') is made in such a way as to have at least one open end. 8. Filter according to claim 7, characterized in that said open end of each tubular filtering septum (30, 30 ') is fixed to a support flange (31), which is adapted to connect the tubular filtering septa ( 30, 30 '), and is provided with at least one through hole (33) aligned with the cavity of said tubular filtering septum (30, 30'). 9. Filter according to claim 8, characterized in that each tubular filter septum (30) is made so that the opposite end is also open, said opposite end being closed by a second support flange (32), which is adapted to connect the tubular filtering septa (30) to each other. 10. Filter according to claim 7, characterized in that each tubular filtering septum (30 ') is made so that the opposite end is closed. 11. Filter according to claim 10, characterized by the fact that said closed end is obtained by flattening and joining the side wall of the tubular filtering septum (30 '). 12. Filter according to claim 1, characterized by the fact that the filter cartridge (3) is arranged so that the tubular filtering septa (30, 30 ') are able to be crossed in parallel by the fluid. 13. Filter according to claim 1, characterized in that the filter cartridge (3) is arranged in such a way that the pre-filtration tubular septum (35, 35 ') and each tubular filter septum (30, 30') are able to be crossed from outside to inside. 14. Filter according to any of the preceding claims, characterized by the fact that the septa (30, 30 ', 35, 35') of the filter cartridge (3) are made of non-woven fabric of polymeric fibers.