Filtration device and use of said device for separating and collecting brake dust

The filtration device enables the separation and collection of dust and particles produced by the pads of a brake assembly. A first separation unit having an air filtration medium, typically annular, is provided in the housing of the device, in order to define an upstream zone where air is admitted, for example tangentially, and a downstream zone in communication with an outlet of the housing for discharging the purified air. The upstream zone is in communication with a lower stage situated lower down, in which a second separation unit is located in order to separate water from particles that have fallen from the upstream zone. A filtration by the second unit is intended to collect clean water and possibly to discharge this water by gravitational flow. The fallen particles remain trapped inside the device, under the first unit.

FIELD

The present invention relates to devices for separating pollutants generated during braking, typically by the action of pads against a rotor disc rotating about an axis. The field of application of the invention relates in particular to separating dust and water to render a brake assembly non-polluting when a road vehicle (for example an automobile, truck, motorcycle) or railway vehicle (train, tram, subway) is braking.

BACKGROUND

In a manner that is known per se, there is a need to treat the dust and particles resulting from the abrasion of friction brake systems. The dust and particles may first be captured by suction, as described for example in patents DE 42 40 873 C2 or FR 3 046 644, and the flow is then filtered through a filtering wall/membrane.

It is also known, from patent DE 20 2008 009 717 U1, to capture and retain the dust and particles in the filter medium, which for example has a U-shaped cross-section, said filter medium being mounted as close to the caliper bracket as possible.

However, these systems are not particularly effective in the long run. When the filter medium is too close to the braking zone, temperatures can approach 600° C., which limits the choice of filter medium and reduces the performance of pollutant reductions.

In addition, captured dust and particles often form a heterogeneous mixture, particularly when there is water as well. Liquid saturation of the filter membrane facilitates premature clogging, for example.

U.S. Pat. Nos. 3,418,789 and 3,980,457 show devices for a compressed air circuit, which clog extremely quickly if used to treat this kind of heterogeneous mixture.

There is therefore a need for reliable and robust solutions that offer a good compromise between efficiency/adaptation to the complexity of the types of dust and particles to be separated, throughout the lifetime of the separation device.

SUMMARY

The present invention aims to overcome one or more of the abovementioned disadvantages by proposing a filtration device which is more effective for separating pollutants, in a suitable manner, from a mixture collected in the braking zone.

To this end, the invention relates to a device for filtering brake dust and particles, intended to collect dust and particles produced by one or more pads of a brake assembly, the device comprising:a housing having an inlet for the intake of an air flow loaded with brake dust and particles and an outlet for the discharge of purified air, andseparation means for retaining the dust and particles, with the distinctive characteristic that the separation means comprise:a first separation unit, housed in the housing and enabling the separation of dust and particles, the first separation unit comprising a filtering element provided with a filter medium and defining an upstream zone in communication with said inlet and a downstream zone in communication with the outlet, the upstream zone also being in communication with a stage called the lower stage located lower down than the first separation unit, the air preferably circulating centripetally through the filter medium to reach the downstream zone,a second separation unit enabling the separation of water from the dust and particles that have fallen from the upstream zone, the second separation unit being located in the lower stage and suitable for filtering the water by retaining dust and particles, preferably by centripetal filtration.

It is thus possible to collect the water in a lower stage which is offset (lower) relative to the streamlines of the untreated air flow admitted into the internal volume of the housing. The inlet may be designed and arranged to direct and optionally accelerate the admitted air flow, possibly by being supplemented with guide members and/or baffle walls which are mounted inside the housing. The addition, at the air inlet, of parts or contours that create reductions in the cross-sectional area is advantageous for accelerating the velocity of the fluid, as in cyclonic technology.

Typically, the lower stage corresponds to a lower portion of the housing, for example a lower portion of a bowl of the housing.

The first separation unit may be superimposed on the second separation unit, within the internal volume of the housing.

This type of configuration makes it possible to have three concurrent effects that are advantageously combined in the device:circulation, which with air can be fast, which simply needs to reach a downstream zone (typically central) before exiting the housing, which reduces the pressure drop,use of gravity to allow the dust and particles circulating/having circulated upstream to fall naturally into the lower stage, typically at the periphery, of the first separation unit,water collection offset towards the bottom to limit interference with the circulation of air near the first separation unit, which makes it possible to collect water droplets both during the supply phases of the device and the shutoff phases, if necessary by releasing a closure member if water is also located on the downstream side.

The filtration device can be compact, without the need for intermediate pipes between the separation units. The compact height makes it possible to reduce the constraints on the clearance required in order to remove the cover from the housing (for example by unscrewing) and to extract an arrangement of separation means in the form of a cartridge mounted as a unit within the internal volume of the housing. This therefore facilitates maintenance operations with replacement of the cartridge.

According to one feature, the separation means are interconnected by superposing the first separation unit on the second separation unit, so as to form the filter cartridge which is mounted as a unit within the internal volume of the housing.

According to one option, the cartridge also has a retaining cap capping the second separation unit and comprising:at least one first guide element, called the upper guide element, preferably forming a generally annular outer edge of the retaining cap, for guiding radially inward the dust and particles falling from the portion of the upstream zone that surrounds the first separation unit,at least one second guide element (called the lower guide element and positioned lower than the first guide element), preferably forming a downward slope, for guiding radially outward the dust and particles that have been guided by the at least one first guide element.

Preferably, the downstream zone extends under a removable cover comprising the outlet and/or includes the hollow inside space annularly defined by the filter medium of the first separation unit.

The second separation unit defines a partitioning in the lower stage, to allow the accumulation of clean water in a collection compartment separate from the location where the dust and particles (pollutants) accumulate.

According to one feature, a bottom is provided in the housing that allows discharging the clean water and which has a slope facilitating the flow of water droplets from the dirty zone to the clean zone, the collection compartment having a purge port located in a low point of said bottom. Optionally, the bottom is conical or partially conical to form such a downward slope towards a central position corresponding to the collection compartment or an access thereto.

According to one feature, magnetic means are provided in the lower stage for collecting metal dust and particles (loaded with ferrous metal). The magnetic means may comprise one or more arcuate strips, forming a concave inner face facing a filtering wall of the second separation unit. The magnetic means are typically formed by one or more permanent magnets.

More generally, the second separation unit comprises one or more magnetic members which:are adapted to attract dust;form all or part of a wall internally defining a tank for trapping/collecting dust; andoptionally are facing an outer face of a filtering material that is permeable to water, preferably felt or other fibrous material.

According to one feature, the filter medium is annular, extending around a longitudinal axis which may correspond to a vertical axis. Pre-separation by a wall of a pre-separator member is typically provided. This wall is generally tubular and arranged in the upstream zone, around the separation unit.

It is understood that the pre-separator member, tubular or partially tubular about the longitudinal axis, may include a piece that is permeable to the air flow loaded with fine particles/impurities and water, which allows a portion of the air flow to circulate between the inlet and the receiving face (typically the outer face) of the filter medium, without bypassing the pre-separator member via the axial end edges of the pre-separator member. For example, the wall of the pre-separator member is rigid and perforated, which renders the pre-separator member permeable in order to admit the flow of air in centripetal directions (distributed around a circumference of the arcuate wall, this wall (radially) surrounding/covering on the outside typically more than one third of the outer face of the filter medium). The air can therefore flow centripetally, directly from an inner face of the wall of the pre-separator member to the outer face of the filter medium.

Preferably, this wall has openings defining narrow passages and forms an obstacle restricting centripetal circulation, in order to maintain adequate distribution between a centripetal flow (subdivided into discontinuous streamlines, according to the distribution of the narrow passages), and a continuous air flow along tangential streamlines, around the separation unit and along a wall of the housing.

The system can be simple and effective for separating liquid particles (water). The streamlines for gas are strongly curved and converge towards the longitudinal axis in a centripetal circulation of the gas flow only after a detour via the passages of the pre-separator, which differs greatly from the path of the heavy dust/particles and water droplets that are displaced outward under the effect of the incoming velocity of the admitted air and the resulting centrifugal force. This minimizes the pressure drops associated with the filtration by the first separation unit.

The filtering element may optionally be in the form of a cartridge that can be extracted from the housing. The annular filter medium may be of pleated paper to form a larger medium surface, so that the filtration efficiency and service life of the medium can be increased.

As an option, the filter medium includes or consists of an annular air filtration unit made of paper, which may be relatively rigid. This medium may extend between two molded flanges (each plastic, typically without metal) forming end caps.

Preferably, the inlet of the housing may be oriented tangentially, in other words opening in a direction away from the downstream zone and tangential/parallel to a side wall of the housing surrounding the upstream zone. When the inlet includes a pipe segment connected to the side wall of the housing, the general guiding direction of this segment may typically be horizontal or inclined downwards or upwards, for example perpendicularly or at an angle between 70 and 90° with respect to a longitudinal axis of the filter medium. An acceleration effect can be obtained when the incline makes it possible to reduce the cross-sectional area of the passage.

According to one feature, the filter medium of the filtering element is permeable to water.

Where appropriate, water can accumulate in an internal collection zone defined by the filtering element (in stage of the device called the upper stage).

Optionally, a water collection compartment is provided in the lower stage, the filtration device having a path for discharging water from the downstream zone to this collection compartment.

According to one feature, the filtration device comprises a collection compartment for the separated water, located in the lower stage. Preferably, the filtration device also comprises water discharge means suitable for causing the water to flow selectively from the downstream zone to this collection compartment and/or to discharge outside the device the separated water collected in this collection compartment. The collection of clean water in a dedicated compartment is thus enabled. In addition, the discharge means are provided in an area placed behind (downstream of) a filter medium, in other words a clean area. This avoids the risk of such discharge means being obstructed by dust or particle solids.

According to one particular feature, the water discharge means are:suitable for discharging the water downwards, in other words in the direction of gravity, andformed separately from the outlet for discharging purified air.

The water discharge means comprise for example:a purge port for emptying the collection compartment, anda closure member, called the first closure member, movable between a position that closes the purge port and a position that opens the purge port.

According to one option for its function, such a closure member can be moved automatically to a purge position when there is no longer any rotation of the rotor disc of the brake assembly. This movement can correspond to a return to a default position of the closure member, in the absence of suction by a collection device associated with the brake or in the absence of another type of pressure differential allowing air to flow through the first separation unit. This is the case for example at shutdown of the vehicle or engine equipped with the brake assembly.

A negative pressure, typically on the outlet side, may be used to close a closure member or other moving part of the discharge means. Such a closure member (referred to as the second closure member in the option where a first closure member is provided for purging the collection compartment) for example allows isolating from one another:the collection compartment, andthe downstream zone where the filtered air flows towards the outlet.

The water discharge means may thus comprise a second closure member, able to place in communication the downstream zone and the central internal volume surrounded by a filter medium of the second separation unit, in an open configuration of the second closure member.

Advantageously, the flow of water is simply due to gravity when the water discharge means are in an open state.

Each of the materials for filtration can allow water to pass through. It is understood that the separation means of the device may have a configuration with an outlet placed on the top of the filter medium, opposite from the lower stage, and at least one obstructing and/or baffle wall which guides the water downward. With such a wall and with the low position of the collection compartment, the device allows discharging excess water droplets into a zone that is offset from the main flow of circulating air.

A pre-separator may be interposed between a side wall of the housing and the outer face of the annular filter medium, to limit the passage of water into the filter medium of the first separation unit.

According to one feature, such a pre-separator is advantageously combined with a cyclone effect, in other words a rapid rotation of the admitted flow of air loaded with dust and particles. The heavy particles are far from the longitudinal axis passing through the hollow space of the annular filter medium and can fall into the lower stage without the need for filtration.

In the following, heavy dust or particles should be understood to mean dust or particles of relatively large size and thus falling quickly due to gravity. The use of tangential acceleration around a substantially vertical axis makes it possible to exert a centrifugal force which contributes to increasing, by agglomeration, the size of the dust pushed outwards, and to facilitating the falling of this dust due to gravity, even during operation of the filter.

The pre-separator may be in the form of a piece or insert forming a deflector for deflecting large dust particles. Among non-limiting examples of a design for this pre-separator, one can mention:the presence of vanes extending to substantially the same height as the height of the filter medium of the first separation unit (or of course to a greater height), with a solid/air-impermeable portion, for example in the form of a smooth outer surface portion facing the air inlet,the presence of a plurality of vanes distributed among at least two heights,the presence of vanes extending for only a portion of the height of the piece or insert, the upper portion able to be solid and typically smooth,the presence of at least one spiral rib projecting radially outwardly to guide the dust and particles into the bottom of the housing,the presence of perforations in a cylindrical body, for example perforations that are circular, rectangular, oblong, or any other shape restricting the dimensions of the perforation (for example less than 4 or 5 mm for the largest dimension of the opening).

Optionally, the vanes have a different orientation than a tangential orientation but with a change of orientation that is less than 90° so that each outer edge of a vane is offset backwards (in the direction of the tangential circulation) relative to the inner edge of the same vane. With this arrangement of vanes, access from the outside to the passages between two adjacent vanes is oriented in the opposite direction to the direction of the tangential circulation of the air flow entering the housing. The vanes define narrow slots for passage between each other, by means of which the streamlines passing through the pre-separator (between adjacent vanes) are bent to form a pronounced angle, the angle at the bend or equivalent angle being for example between 30 and 90°, preferably between 45 and 85°.

The lower stage can form a dust trap and is for example defined by a part forming a cap, typically having a frustoconical or convex portion, widening radially outwards with axial distancing relative to the first separation unit. The frustoconical portion has one or more openings and extends around a central pipe segment that can serve as a fluid connection that is fluidtight (relative to the upstream zone), between the downstream zone and the collection compartment.

More generally, it is understood that the device makes it possible to discharge an overflow of water droplets downwards and that the lower stage can form both a dust tank, for example for dust trapped by magnetic means, and a collection compartment for water that can be purged.

A dust barrier element may be provided in the lower stage, for example to form a separation between the dust tank and the water collection compartment.

The barrier element may be annular in shape and internally defines a central internal volume of the lower stage.

According to one option, the second water separation unit forms a lower end of the filtration device and comprises the collection compartment, the dust collection tank formed in the lower stage being separated from the collection compartment by a dust barrier element which preferably has a tubular shape. An additional filtering element can supplement the tubular barrier element, for example by being placed at the bottom of the collection compartment where a discharge passage for purging is formed. Such an additional filtering element, optionally based on felt, provides safety: it ensures that it is indeed clean water that is released into the environment.

The closure member of the purge valve is typically movable in order to be able to be in a closed position, particularly when there is negative pressure in the lower stage. Such a closed position prevents interference with the flow towards the outlet, especially in operating conditions without water in the collection compartment.

In various embodiments of the filtration device according to the invention, one or more of the following arrangements may be provided:the filter medium extends between two molded flanges forming end caps,the flanges are typically distinct from the pre-separator member, a flange called the lower flange of the filtering element being able to bear/rest directly (axially) on the upper face of a transverse base of the pre-separator member.the inlet opens internally into a region of the upstream zone located or defined (preferably entirely located) axially between the upper flange and the lower flange.the collection compartment comprises the central internal volume defined by the barrier element of the second separation unit and possibly an underlying volume, in communication with the central internal volume via a passageway formed in a bottom wall of the housing or in an annular support of the barrier element sealingly connected to a lower edge of the barrier element.the filter medium in the first separation unit is suitable for retaining retain light dust, in particular loaded with little or no metal,the first separation unit comprises a pre-separator member, located in the upstream zone and surrounding the filter medium, forming a perforated or openworked annular deflector in order to be permeable to light dust, the outer face of the annular deflector being suitable for guiding towards the lower stage the heavy materials that are less volatile than light dust, in particular heavy dust loaded with metal and liquid droplets.the inlet has a tangential outlet into the internal volume of the housing and the pre-separator member is preferably without any through-openings in a portion adjacent to the inlet.the outer face of the annular deflector is suitable (for example with elongated reliefs along a circumferential direction) for guiding in a tangential direction, and forms bending edges for streamlines transferring air from the upstream zone to the downstream zone.the second separation unit comprises or is surrounded by one or more magnetic members.the one or more magnetic members are suitable for attracting dust and particles in order to retain them below the inlet and, preferably, below the first separation unit.the one or more magnetic members form all or part of a wall internally defining a dust collection tank.the one or more magnetic members are facing an outer face of a filter material, preferably felt, that is water-permeable.the first separation unit comprises an air-filtering filter medium comprising paper.the second separation unit has a water-permeable fibrous filter material, the paper for air filtration preferably being more rigid than the fibrous material.in one option, the first separation unit and the second separation unit share a common filtering element, which extends for example around the water collection compartment and around the downstream zone.the second closure member is mounted in a lower central opening of the first separation unit.the separation means comprise a retaining cap capping the second separation unit and forming an interface between an annular portion of the upstream zone surrounding the first separation unit and the lower stage.the retaining cap has an outer annular edge that is distal to a central axis of the filter medium, the outer annular edge preferably being close to or in engagement with an external side wall of the housing, and a central portion defining an axial opening suitable for attachment to at least one among the first separation unit and the second separation unit.one or more openings are provided between the central portion and the outer annular edge, the retaining cap having an upper face inclined downwardly towards the one or more openings extending from the central portion.the retaining cap has a radial portion, preferably frustoconical, forming the inclined upper face and which extends between the outer annular edge and the central portion.a tank for trapping brake dust and particles is defined (in the lower stage) between the radial portion of the retaining cap and a bottom wall of the housing, this bottom wall preferably being inclined towards a central low point of the lower stage.the one or more magnetic members are adjacent to a bottom wall of the housing and/or contiguous to a side wall of the housing defining an internal volume of the housing in which the separation means are entirely housed.

Also proposed is a brake assembly which is non-polluting in that it essentially eliminates the emission of particles or dust into the atmosphere.

More particularly, the brake assembly, advantageously non-polluting, comprises:the filtration device,a caliper bracket,a rotor disk rotating about an axis,at least two movable pads intended to press on the rotor disc in order to brake it with a clamping force provided by a bracket, the pads comprising friction material capable of releasing particles resulting from abrasion,a collector device at least partly arranged close to the caliper bracket, the collector device comprising:at least one inlet, anda connecting element, connected to an outlet of the collector device and in communication with the inlet of the filtration device.

According to one feature, the collector device has suction means at least partly arranged close to the caliper bracket, so that each inlet of the collector device is defined by a suction zone formed in the vicinity of each pad and delimited by a deflector.

Also proposed according to the invention is a use of the filtration device in a vehicle or rolling stock, wherein the inlet formed by the housing defines a hollow tube on which is fixed a connecting element, preferably a hose, for connection to a brake dust collector device, the housing of the filtration device being attached by attachment means to a leg of a suspension shock absorber.

Also proposed according to the invention is a use of the filtration device in a vehicle or rolling stock, wherein the lower stage of the filtration device serves to keep brake dust and particles around the second separation unit and under a retaining cap inserted into the housing (preferably inserted under the first separation unit).

Also proposed according to the invention is a use of the filtration device in a vehicle or rolling stock generating brake dust and particles, wherein one or more magnetic members are provided in the lower stage in order to attract and retain brake dust and particles in the lower stage.

Magnetic attraction reduces the risk that dust, particularly heavy dust loaded with metal, will rise (for example in case of jolts) to same height as the first separation unit.

DETAILED DESCRIPTION

In the various figures, identical references indicate identical or similar elements.

With reference toFIGS.1and7, the filtration device1is provided in order to separate and collect dust and particles produced by pads72a,72bof a brake assembly7. The device or filter1comprises a housing2which has an upper wall and a lower wall.

As is clearly visible inFIG.7, the housing2is interchangeably connectable to one or possibly multiple channels of a circuit supplying air loaded with brake dust. This circuit is connected to a collector device100that is part of a brake assembly7. Here, the collector device100has suction means at least partly arranged near the caliper bracket71associated with the rotor disk D, so that each inlet of the collector device100is defined by a suction zone formed in the vicinity of each pad72a,72bwhich is engaged against the rotor disk D. The inlet of the collector device100may be defined by a deflector, for example as described in document FR 3,046,644.

An inlet3formed by the housing2may define a hollow tube C3on which is fixed a connecting element13, here a hose, for the connection to the collector device100. The hose optionally splits into two branches13a,13bto allow collecting dust from the friction zones respectively associated with the two pads72a,72b.

The housing2may be made integral to a component installed in the lower part of the vehicle or rolling stock equipped with the brake assembly7. In the illustrated example, the housing2is attached, by means of attachment means92(optionally with screwing/bolting), to a leg91of a suspension shock absorber90.

As illustrated in the longitudinal sectional view ofFIG.1, the housing2comprises an external side wall2bwhich extends from the bottom wall2ato the upper wall of the housing2. The bottom wall2aforms a lower end E1with an opening200which allows purging water by gravity.

The housing2of the filter1may have a substantially tubular shape about a central axis. In the non-limiting example of the figures, the bottom wall2aof the housing2is defined by or is part of a bowl50, typically of metal or plastic. This bowl50may optionally form a stationary portion in the example shown.

The remainder of the housing2is removably fixed with respect to this bowl50in order to seal closed the opening50bof the bowl50. The upper wall is formed here by a cover2c, which is sealingly connected to the bowl50, here by screwing. A male thread may be provided on the cover2cto engage with the female thread2dformed in an upper end of the side wall2b. An upper opening is formed in the cover2cby a hollow tube. More generally, one can see that the housing2has an outlet4which may be located on the end opposite from the bottom wall2a. The example illustrated in FIG.1with a central hollow tube to form this outlet4is only provided as a non-limiting example.

In some embodiments, the cover2cmay have a flattened shape rather than a dome shape. Moreover, the outlet4may correspond to an opening which can directly form an interior passage of a turbine. For example, the bowl50or similar housing component may be closed by an electric turbine.

The housing2may form or be connected to a water separation stage, preferably in the form of a lower stage8. The water separation stage may be offset downward relative to an interior zone of the housing located at the same level as the inlet3. An air filtration stage may be defined in this interior zone which is typically at least in the upper portion of the housing2, at a distance from the bottom wall2a.

With reference toFIGS.1and4, the cover2cmay provide the outlet4, while the inlet3is formed on the bowl50or on a side wall2bof the housing2.FIG.4shows the case of a bowl50made of one piece which includes the bottom wall2a, from which the annular side wall2bextends upward.

The bowl50defines a dust tank R8and further provides a collection compartment CC where water W can accumulate, provided that the opening200is closed off. This collection compartment CC and the tank R8are present in the lower stage8(water separation stage). The height of the bowl50is for example greater than 50 or 60 mm and preferably exceeds the height of the cover2c. The water separation stage may have a height that is at least equal to 25 or 30 mm, and typically integrated in the bowl50.

In this example, the bowl50also defines all or part of a chamber for housing the filtering element5of a first separation unit10, visible inFIGS.1,2, and3. The chamber for the filtering element5is axially distant from the bottom wall2a.

The upper end50aof the bowl50is annular. Such a bowl50can be gripped with one hand, the outer diameter or equivalent dimension of the side wall2btypically being less than 15 cm. Optionally, the cover2cmay extend substantially over the filtering element5.

In this case, the side wall2bof the housing2is formed only by the bowl50. According to another option, it is also possible to provide an intermediate housing component (not shown) which extends around the central axis between open axial ends, respectively upper and lower, this housing component having a generally cylindrical side wall or other suitable shape which defines all or part of the chamber for housing the filtering element5. In this case, the cover2cis attached to the upper end of the intermediate housing component, while the bowl or tank/similar bottom is attached to the lower end of the intermediate component. The intermediate housing component then forms a connection adapter between the bowl and the cover2c.

It is preferred to use a cover2cwhich is fixed in a removable manner, in order to be able to replace at least the filtering element5.

Furthermore, it is intended to place a partitioning element9in the housing2, here able to engage against the top of the side wall2bto form a seal, typically by means of an annular seal J1. A groove G, visible inFIG.4, may be formed in the upper end50a. The zone for screwing by use of the female thread2dcan then extend into this groove G, while the seal J1comes to press radially against an annular projection53defining the inner side of the groove G.

The partitioning element9has a typically flat and annular shape, with a through-opening9a. The through-opening9a, here central/centered on the axis of the housing2and the longitudinal axis X of the filter medium6of the filtering element5, allows communication between the outlet4and a hollow inside space6cof the filtering element5. The partitioning element9is held in position axially between two opposite abutment zones9b,20beach forming a support that is typically annular. A first axial abutment zone9b, of annular shape, is formed by contact against the cover2c, here against a radial section S2close to the threaded portion of the cover2C. This radial section S2is axially facing an internal rim of the side wall2bwhich forms the axial abutment zone20bfor supporting the partitioning element9from below.

The filtering element5(forming a filter insert) has, as can be seen inFIGS.1and3, a filter medium6, a first flange hereinafter referred to as a lower flange51, a second flange hereinafter referred to as an upper flange52, and an internal longitudinal component T extending between the lower flange51and the upper flange52. The longitudinal component T, here in the form of a perforated tube, can stiffen the filtering element5. The filter medium6preferably extends about its longitudinal axis X which can correspond to a central axis for the filtration device1.

The filter medium6, for example of paper or similar material, is suitable for air filtration. This filter medium6may be folded into a star shape to increase the surface area of its outer face6aand facilitate filtration of fine particles.

In the housing2, the filtering element5forms an insert received in the cavity of an annular wall of a pre-separator member40, said annular wall forming a deflector element45. The pre-separator member40is preferably rigid and forms a lateral sleeve-style casing around the outer face6aof the filter medium6. The pre-separator member40and the filtering element5form a first separation unit10housed in the housing2. This first separation unit10is mounted immediately below the partitioning element9in the non-limiting example ofFIG.1.

The filter medium6, which is annular, has an outer face6akept at a distance from the annular wall45and an inner face6bin contact with the elongate structural element T, for example only at external ribs of this element T.

Two opposite openings O1, O2are respectively provided in the upper flange52and in the lower flange51. The hollow inside space6c, defined by the internal face6b, forms a downstream zone Z2relative to the filtration enabled in a centripetal direction. An annular inner edge of the partitioning element9is located near the upper exit of the hollow inside space6c, so that opening O1and opening9aare axially aligned and more or less coincident to allow the air filtered by the filtering element5to flow upwardly and to be discharged from the device1via the outlet4located higher than the partitioning element9. The cross-sectional area of the outlet4may be much smaller than the cross-sectional area of opening O1.

A superposition of the partitioning element9and the upper flange52, with the use of an intermediate annular seal J2and the use of seal J1, makes it possible to separate in a sealed manner the downstream zone Z2from the portion of the upstream zone Z1formed at the periphery of the filter medium6(towards the outer face6a). These seals J1and J2may be compressed radially and/or axially. Of course, other configurations may be used, for example to reduce the number of seals or possibly to integrate a sealing member into the upper flange52against the side wall2band an engagement means in abutment under the cover2c.

The use of a partitioning element9distinct from the upper flange52may be advantageous for mounting and maintaining one or more guide members and/or baffle walls, mounted internally in the housing2at the periphery of the first separation unit10. More generally, there may be added, at an exit3atangential to the inlet3for air loaded with dust F, guide pieces54or reliefs that create reductions in the cross-sectional area. This makes it possible to accelerate the fluid velocity and to form streamlines tangential to the external side wall2b, as in cyclonic technology.

In addition, the tangential exit3ais only illustrated as an option, here to form a suitable exit in the side wall2b. In some variants a substantially radial exit or a different exit may be provided, associated with a deflector to deflect the flow of air against one or more outer walls against which the heaviest solid particles and water droplets can fall more or less gradually. For example, the exit may be opposite a baffle suitable for deflecting the flow at approximately 90°, to allow tangential circulation along an outer wall facing the first separation unit10.

In the non-limiting case ofFIGS.1to3, we can see an arrangement with one or more guide pieces54placed in a protrusion25(protruding outwardly) from the side wall2b.

The protrusion25, visible inFIG.4, is formed in an upper portion of the side wall2b, for example in an angular sector of about 90°, 120°, or 180° relative to the axis of the device1(in other words a quarter, a third, or half of the circumference of the upper portion of the side wall2b). The lower portion of the side wall2bmay be more regular, for example with a circular circumference. The internal exit3aof the inlet3is formed at a first end25aof this protrusion25, here under an annular wall FG forming the bottom of the groove G. The protrusion25makes it possible to form an outwardly offset guide channel56, with a smaller curvature than a passage which extends flush with the pre-separator member40.

A guide piece54may have an external rib55parallel to the longitudinal axis X of the filter medium6. This rib55forms an obstacle in the annular space around the first separation unit, which prevents particles/dust having already made one trip around the upstream zone Z1from continuing to travel around the first separation unit10. Thus, such particles/dust encountering this rib55cannot mix with the flow entering by the inlet exit3a.

With reference to the non-limiting example ofFIG.3, the guide piece or pieces54may define two passages: an external passage P1corresponding to a guide channel56for air coming out of the inlet exit3a, located radially outward of the guide pieces54, and an inner passage P2flush with the outer face of the pre-separator member40, on the inner side and parallel to the outer passage P1. The inner passage P2serves for the tangential circulation of particles that have already made at least one trip around the pre-separator member40of the first separation unit10.

An external radial relief and/or an additional piece, here forming a slightly upward slope3b, allow accelerating the speed of circulation in the channel56. Under this slope3b, an obstructing wall acting as an obstacle similar to the role of the rib55may be provided, in order to cause particles to drop lower down. A guide extension54bmay be formed under a narrower end zone of the guide channel56. This guide extension has for example an inverted L cross-section when the slice is longitudinal and through the central axis of the device1. The top of this guide extension54bforms the free end of the slope3b.

The second end25bis at the same height as the first end25a, under the annular wall FG (here the wall forming the bottom of the groove G). It is understood that the air flow is channeled between three elements: the annular wall FG, the inner face of the side wall2b, and the shoulder EP defining the bottom of the protrusion. The one or more guide pieces54may be arranged in abutment against the shoulder EP and in engagement with the internal edge of the annular wall FG in order to delimit/define, with the three abovementioned elements, the guide channel56, clearly visible inFIG.1. With this guidance in the guide channel56, tangential streamlines are generated around the pre-separator member40which forms the outer face of the first separation unit10.

The tangential admission of air F and the acceleration caused by the reductions in cross-sectional area in the peripheral zone in the first separation unit10, contribute to pushing the dust and particles towards the outside by centrifugal force, against the side wall2bof the housing2. This effect enables the particles located the most peripherally to the tangential flow in the upstream zone Z1to drop, these particles in practice being the heavier particles.

The pre-separator member40may optionally include one or more spiraling ribs57which progressively descend, thus encouraging the descent of the dust and particles to below the height of the protrusion25. More generally, this type of descending guidance (in a progressive descent, which typically requires one trip around the filter medium6) by the outer face of the first separation unit10, can be an advantageous option when the air to be filtered admitted into the housing2is first channeled in a tangential flow channel before being centripetally filtered.

In general, a pre-separator member40may be provided having outwardly protruding reliefs (for example the ribs57) which oppose a direct vertical downward movement of the air flow along the outer face of the pre-separator member40, thereby increasing the path/travel length of streamlines along the perforated regions of the annular wall forming the deflector45.

The pre-separator member40may have a wall portion40awhich is solid near the second end25b, where the guide channel56ends. The longitudinal extension54b, when present, is facing this wall portion40a.

In this embodiment option, the creation of streamlines with a centripetal component is not allowed before a tangential path threshold length is exceeded. Such a threshold length enables significant acceleration of the flow of air circling around the pre-separator member40.

Referring toFIG.2, the pre-separator member40may have many access passages48in the outer face6aof the filter medium6, here outside the wall portion40a. The access passages48are narrow in the direction of flow and may optionally be elongate in the vertical direction or a similar direction parallel to the longitudinal axis X of the filter medium6.

The pre-separator member40defines a receiving space where the filtering element5can be housed coaxially with a lower tube43integrally formed with an annular base B of the pre-separator member40. Here, a single rigid piece forms the pre-separator member40, but a design with multiple assembled parts may be provided. A deflector element45, formed by the annular side wall of this pre-separator member40, extends upwardly from the base B.

As can be seen inFIGS.1and3, the lower flange51of the filtering element5can rest directly on the upper face of the base B. In order to minimize the radial spacing between the outer face6aand the side wall2bof the housing2, the lower and upper flanges51,52may be in radial contact against the inner face of the deflector element45. Here these flanges51,52cover the axially opposite faces of the filter medium6in an adjusted manner. The annular deflector45is openworked or perforated to form the access passages48, so as to be permeable to light dust.

The outer face of the annular deflector45may be adapted to guide, towards a lower stage8, heavy materials that are less volatile than light dust. Here, the spiral ribs57, preferably continuous and formed integrally with the side wall of the pre-separator member40, enable such downward, advantageously progressive, guidance.

Heavy materials include, in particular, heavy dust loaded with metal and liquid droplets. The acceleration in the guide channel56or in a similar entry zone of the air flow F makes it possible to project and maintain these materials (by centrifugal force) against the outer wall defining the upstream zone Z1, in other words the internal face of the side wall2cin the example illustrated inFIG.1.

The filter medium6is suitable for retaining light dust, in particular loaded with little or no metal, such dust being less susceptible to the centrifugal effect. With reference toFIG.2, such light dust can pass between two radial vanes47each having a similarly modified orientation relative to the radial direction.

These vanes47may be flat but oriented at an angle of 5 to 45°, preferably 10 to 40°, relative to a radial direction passing through the axis longitudinal X. This angular offset is positive, in the direction of the peripheral circulation around the first separation unit10, so that the deflection necessary to change from a tangential direction to a direction of entry into the unit10, between two successive vanes47, is not 90° but an angle greater than 90° (between 95 and 135°, preferably between 100 and 130°).

The presence of vanes47extending to substantially the same height as the height of the filter medium6, with a portion40athat is solid/air-impermeable, is a non-limiting example of the design of the pre-separator member40. It is also possible to provide a plurality of vanes47distributed among at least two heights, or extending over only the lower portion of the height (at the base B but without any side passage near the upper edge40b). In this variant (not shown), the annular upper portion of the deflector element45may be solid (typically smooth). In other words, the portion40aforming a solid vertically extending band is replaced by a solid annular band.

Alternatively, other ways of defining narrow access passages48may be provided, for example by perforations distributed annularly over all or part of the circumference of the deflector element45.

Moreover, it is possible to eliminate the spiral rib or ribs57. Optionally, similar reliefs may be formed/added on the internal face of the side wall2cof the cover2.

Referring now toFIGS.1,5, and6, the integration of the second separation unit20and the treatment of the particles and water droplets which fall into the lower stage8, below the first separation unit10, are now described.

The upstream zone Z1, typically annular and formed along the side wall2c, is subdivided into a first portion or sub-zone surrounding the filter medium6of the first separation unit10and a second portion or sub-zone which is lower, located in the lower stage8. While the first sub-zone forms a spiral circulation circuit for the heavier dust and particles, optionally with some zones where they fall faster (for example along the rib55), the second sub-zone may be at least partially sheltered from the circling streamlines, in the tank R8formed under a retaining cap30.

With reference toFIGS.1and6, the retaining cap30may be an intermediate piece placed between the lower tube43forming the lower end of the first separation unit10and the top of a second separation unit20. More generally, a retaining portion or piece is provided under the base B, which limits the vertical ascent (in case of jolting) of dust that has fallen into the lower stage8located towards the bottom wall2aof the housing2.

The second separation unit20comprises a collection compartment CC where water W can either accumulate or be purged. This collection compartment CC may be at least partly internal to the housing2or is sealingly connected to the internal volume V via a pipe leading towards the bottom wall2a.

In the illustrated example, it is the lower stage8, internal to the housing2, which forms the tank R8for trapping the fallen dust and particles. This tank R8preferably extends annularly around the second separation unit20. A dust barrier element21that is part of the second separation unit20separates the tank R8from the collection compartment CC.

When water is present in the admitted flow of air F, the dirty droplets collected in the tank R8fall against the bottom wall2aor other wall defining a bottom of the tank R8. As is clearly visible inFIG.1, the bottom of the tank R8may form a slope. Optionally the bottom is conical/frustoconical or partially conical to form such a downward slope towards a central position corresponding to the collection compartment CC or an access thereto. Here, the slope is shaped like a funnel but preferably with a gentle slope. The incline may continue from the side internal to the barrier element21, and/or a central low point PB of the lower stage8is formed which may be located below the level of a lower end of the barrier element21.

In other words, in the lower stage8, the filtration may be carried out passively, gravity alone causing the water droplets to travel from the peripheral tank R8to the collection compartment CC. The slope facilitates the flow of water droplets from the dirty zone to the clean zone. Typically, the collection compartment CC has a purge port22located in a low point of this bottom. The purge port22may optionally have a plurality of openings24in a lower cap28of the second separation unit20.

There is also a first closure member C1, movable between a position that closes the purge port22and a position that opens the purge port22. This first closure member C1may optionally be closed when the weight of the filtered water W remains below a threshold. The first closure member C1may optionally be controlled by a control unit.

It is understood that the use of valves41,42with a respective flexible closure member C1, C2is a solution that is simple in design. Although the figures show two passive closure members C1, C2, electromagnet controls of active valves of another type can be used. More generally, any type of discharge means41,42can be provided for discharging the water and preventing it from remaining trapped in the housing2.

The barrier element21may comprise or consist of a tubular filtration medium, mounted on a stiffening structure27. The barrier element21here is permeable to water and surrounds or internally defines a central internal volume V2of the lower stage8. This central internal volume V2may form all or part of the collection compartment CC for clean/filtered water W.

The central internal volume V2may optionally be in communication with the hollow inside space6cvia the opening O2in the lower flange51and a passage through the base B which may be defined by the lower tube43. This type of passage can enable water droplets collected in the downstream zone Z2to fall, these droplets for example able to form by coalescence while passing through the filter medium6of the first separation unit10. The passage is preferably obstructed as long as air is actively filtered (via a pressure difference) into the first separation unit. The closure member C2of the valve42for example enables this obstruction, here by closing openings24′ formed in a bottom member located under the hollow inside space6c.

More generally, it is understood that the filtration device1may have a water discharge system suitable for causing the water W to circulate selectively from the downstream zone Z2to the collection compartment CC and/or to discharge the separated water W accumulated in the collection compartment CC to outside the device1.

An additional filtering element26may supplement the tubular barrier element21, for example by being placed at the bottom of the collection compartment CC. Such an additional filtering element26makes it possible to release very clean water. Felt may be used for filtration of the water W, in the barrier element21and/or in the additional filtration element.

A configuration with one or more closure members C1, C2allows discharging the water W downwards in the direction of gravity, without any source of energy. The one or more closure members C1, C2for the flow of water are formed separately from the outlet4for the discharge of purified air, preferably in respective lower ends of the first separation unit10and second separation unit20. These ends are formed by the valves41,42.

In the non-limiting example ofFIG.6, a second closure member C2, placed above the first closure member C1, is kept closed when there is negative pressure in the housing in the downstream zone Z2. When the circuit supplying the device1is shut off, this second closure member C2deforms elastically towards its default shape/configuration to close off the through-passage. The seat of the second closure member C2may be formed by a piece SC2separate from the lower flange51which is mounted internally against an upper face of the lower flange51. The longitudinal component T may extend between the two flanges51,52by abutting axially against a collar of this piece SC2. The openings24′ are formed in this piece SC2, for example around a central passage through which an axial member for anchoring the closure member C2is mounted.

As for the dust and particles, these are retained on the outer side by the barrier element21. In addition, to reduce or eliminate the risk of clogging the barrier element21, it is possible to move the dust radially outward by the use of magnetic members M such as magnets. The barrier element21of the second separation unit20may thus be surrounded by one or more magnetic members M which are suitable for attracting dust and particles. The internal face FM of the magnetic members M, which are concave, may extend for example at a distance (possibly constant) that is more than at least 15 or 20 mm from the outer face of the barrier element21.

Permanent magnets, for example arranged in the form of an outer ring, improve retention under the retaining cap30, at a height that is below the inlet3, and preferably below the first separation unit10.

With reference toFIGS.1and5, the magnetic members M are placed at the bottom of the interior volume V of the housing2, at an axial distance from the retaining cap3. The retaining cap30here covers the second separation unit20and forms an interface between the lower stage8and the annular portion (first sub-zone) of the upstream zone Z1surrounding the first separation unit10.

This retaining cap30may be contiguous to or adjacent to the side wall2b, at an outer annular edge35distal to the central axis X of the filter medium6. The retaining cap30may have an annular portion forming a upper guide element for guiding radially inward the dust and particles falling from the portion of the upstream zone Z1surrounding the first separation unit10. The outer annular edge35may be close to or in engagement with the outer side wall2b.

The retaining cap30also forms a lower guide element (located lower than the first guide element), having a downward slope profile, for guiding radially outward the dust and particles that have been guided by the upper guide element, traveling through an opening or a first series of side openings36close to the side wall2b.

The retaining cap30is for example held in position, above the second separation unit20, by a central portion32defining an axial opening33and suitable for engaging in or around the lower tube43. An annular sealing contact, optionally with the aid of an annular bead, enables sealing the connection between the lower tube43and the central portion32, also of tubular shape.

The retaining cap30optionally has a skirt J3, parallel and concentric to the central portion32, which may be fixed to an annular upper end of the second separation unit20. This skirt J3optionally is externally supported against the barrier element21, by radial annular contact.

The lower guide element may be in the form of a radial portion31, preferably frustoconical, which extends between the central portion32and the outer annular edge35. The radial portion31may optionally be perforated with axial openings37near an annular lower edge39of the piece forming the retaining cap30(openings37distanced from the central piece32). Longitudinal connecting arms34, substantially parallel to one another for example, can connect, from the annular lower edge39, the lower guide element to the upper guide element. The spaces between the connecting arms form said side openings36.

Exemplary arrangements, with at least a replaceable portion or replaceable cartridge, will now be discussed with reference toFIGS.1,4, and6.

The filtration device1shown inFIG.1allows unscrewing the cover2c. According to one option, it is thus possible to extract at least the partitioning element9and the first separation unit10. An operator can thus selectively change the first separation unit10.

In a variant, the lower stage8may optionally be designed as a detachable element, for example by being associated with a bowl component which includes the bottom wall2aand a portion of the side wall2bwhich extends under the protrusion25. In this case, unlike the one-piece bowl illustrated inFIG.4, an operator can selectively unscrew or disassemble the bowl component in any manner in order to separate the lower stage8and replace both the bowl component and the second separation unit20. This system makes it possible to keep a stationary portion forming the upper part of the bowl50and thus to preserve the protrusion and the associated guide pieces54.

In the illustrated option or in similar options, the housing2may be arranged to allow the insertion of all the separation means (10,20,30), as one unit. In this case, it is understood that the first separation unit10, the retaining cap30or similar member, and the second separation unit20are interconnected with each other, typically by superposition, so as to form a filter cartridge60mounted as one unit into the internal volume V of the housing2. Typically, the guide piece or pieces54(possibly reusable) can also be removed with the cartridge60. In this case, a removable design of the portion (FG,53) which supplements the outer housing wall to form the groove G may be provided, possibly by making it integral with the partitioning element9.

With reference toFIG.6, the filter cartridge60may form a distinct unit of an extractable basket or other type of casing to which the magnets or similar magnetic members M are integrally secured. A basket design with magnets removably attached to the basket can allow easy removal of the disposable tank R8(filled with particles/dust) and reuse of the magnets in the new replacement cartridge.

Referring now toFIG.7, it can be seen that the housing2can be attached to a leg91of a suspension shock absorber90. The fastening members92can be distributed in one or more attachment areas. The axis of the filter (and the longitudinal axis X of the filter medium6) are substantially vertical, to take advantage of the gravitational effect. The housing2may be placed entirely above or partly above the axis Y of rotation of the rotor disc D (brake disc). There remains sufficient access, along a spring of the shock absorber90for example, to be able to remove the cover2cand make a replacement when necessary without removing the entire bowl50(without disassembly at the fastening members92). Alternatively, an operator can unmount the entire filter and then replace all or part of the device1before reattaching the filter to its support on the machine/vehicle.

The device, coupled with a suction system, can prevent rapid fouling of the wheel rims by braking residues and renders the brake assembly7non-polluting in comparison to conventional braking systems that have no dust collection and treatment device.

It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. Thus, the bowl50and the substantially bell-shaped cover2cmay be designed and/or assembled together differently. The assembly of these elements may be done using any suitable method of attachment, screwing corresponding to a preferred (but non-limiting) option for making the assembly of the device1particularly simple and robust. In addition, the cover2cmay be formed by a wall that is part of a functional component, for example a turbine or other means for suctioning clean air and forming the outlet4.

Furthermore, it is understood that the options for arranging the respective separation units10,20or other complementary elements are usable independently of the complete structure retained for the device as a whole. Thus, the features and structures described in detail for filtering the water can be considered as simple options to supplement the teachings of filtering the air by allowing the heaviest dust to fall to a lower stage8, just as the features and structures described in detail for guiding and filtering the air centripetally may be considered as a non-limiting option for filtering the air in a filter combining an air filtration medium and a second separation unit in a lower stage8.