EP3129151B1 - Filtering device - Google Patents

Description

The present invention relates to a device for purifying a gaseous medium loaded with particles of all kinds, such as dust particles, organic particles in suspension in the exhaust gases of all kinds and in particular from diesel engines. ..

It is more particularly intended for use in an industrial installation, an establishment (hospital, restaurant, etc.) or even a building for residential use (house, apartment), in particular in the form of a mobile device.

The applicant has already proposed this type of device for treating a gaseous medium laden with particles, but intended more particularly for the exhaust gases of an internal combustion engine (cf. in particular the patent application WO 01/19525 ).

This treatment device comprises a corona-effect electrofilter comprising a longitudinal casing of cylindrical shape in which extends a longitudinal passage for the gases to be treated, an emissive structure extending longitudinally in the center of the passage and a collecting structure extending longitudinally between the passage and the envelope and comprising a plurality of cavities forming housings for trapping the particles contained in the gaseous medium, the emissive structure comprising a plurality of serrated plates arranged transversely to the longitudinal direction and forming points directed towards the collecting structure . These serrated plates are all carried by a rod connected to a circuit providing a stabilized high voltage. Another device for purifying a gaseous medium loaded with particles is described in JP S58 119355 A .

The present invention aims to provide a device of this type, better suited to the uses mentioned above, while remaining effective, and also leading to other advantages.

It proposes, for this purpose, a device for purifying a gaseous medium laden with particles as defined in claim 1.

Thanks to these provisions, the present invention proposes a purification device optimized in terms of efficiency as well as the aforementioned uses.

It is indeed in particular possible to orient each of the emissive structures or electrodes as desired, in particular to obtain for example effects of ozone production or not, to play with the flow of the gaseous medium in the filtration chamber , or even bringing each of the electrodes individually to a different voltage.

More generally, these arrangements also make it possible to produce a device that is easy to manufacture and also to maintain which, moreover, can be produced, as needed, in the form of a compact structure.

• l'une au moins des structures émissives est montée orientable dans la chambre de filtration électrostatique ;
• chaque plaque se présente sous la forme d'une lame pouvant être vrillée ;
• chaque plaque présente, de part et d'autre d'une surface centrale de déflexion, des échancrures formant entre elles lesdites pointes ;
• lequel les pointes sont disposées en quinconce le long de deux bords opposés de chaque plaque ;
• les bords des plaques pourvus des pointes s'étendent jusqu'au voisinage des structures collectrices, en ne laissant subsister qu'un espace évitant la formation d'arcs, dans une position dans laquelle les plaques s'étendent perpendiculairement aux structures collectrices, parallèles entre elles ;
• chaque plaque comporte une tige en saillie sur chacun de deux bords de montage opposés, pour le montage de la plaque sur un support ;
• le support se présente sous la forme d'un cadre pourvu, pour la réception de chaque tige, d'une ouverture de passage de celle-ci ;
• chaque structure émissive est portée à haute tension, de préférence à une tension de l'ordre de 10 kV ;
• chaque structure collectrice est portée à haute tension, de préférence à une tension de l'ordre de 5 kV ;
• les structures émissives sont alignées, suivant un alignement parallèle aux structures collectrices ;
• chaque structure collectrice a une forme de parallépipède rectangle ;
• chaque structure collectrice comporte une plaque collectrice montée sur un cadre et ayant au moins un élément de raccordement à un circuit fournissant une haute tension, isolé électriquement du cadre.

According to specific provisions, which can, if necessary, be combined with each other:

• at least one of the emissive structures is orientably mounted in the electrostatic filtration chamber;
• each plate is in the form of a blade which can be twisted;
• each plate has, on either side of a central deflection surface, notches forming said points between them;
• wherein the spikes are staggered along two opposite edges of each plate;
• the edges of the plates provided with the points extend to the vicinity of the collector structures, leaving only a space to avoid the formation of arcs, in a position in which the plates extend perpendicular to the collector structures, parallel between they ;
• each plate has a rod projecting from each of two opposite mounting edges, for mounting the plate on a support;
• the support is in the form of a frame provided, for receiving each rod, with an opening for passage thereof;
• each emissive structure is brought to high voltage, preferably to a voltage of the order of 10 kV;
• each collector structure is brought to high voltage, preferably to a voltage of the order of 5 kV;
• the emissive structures are aligned, following an alignment parallel to the collecting structures;
• each collector structure has the shape of a rectangular parallelepiped;
• each collector structure comprises a collector plate mounted on a frame and having at least one element for connection to a circuit supplying a high voltage, electrically insulated from the frame.

• la figure 1 est une vue schématique en perspective d'un dispositif de purification d'un milieu gazeux chargé de particules, conforme à la présente invention ;
• la figure 2 est une vue éclatée, à échelle différente, des principaux éléments du dispositif de la figure 1 ;
• la figure 3 est une vue en plan, schématique et à échelle différente, d'une structure émissive de ce dispositif ;
• la figure 4 est une vue schématique en perspective d'un support de structures émissives selon un autre mode de réalisation de la présente invention ; et
• la figure 5 est une vue en plan, schématique, d'une structure émissive selon un autre mode de réalisation de l'invention.

Other objects, characteristics and advantages of the present invention emerge from the following description, made with reference to the appended drawings, in which:

• the figure 1 is a schematic perspective view of a device for purifying a gaseous medium laden with particles, in accordance with the present invention;
• the figure 2 is an exploded view, on a different scale, of the main elements of the device of the figure 1 ;
• the picture 3 is a plan view, schematic and on a different scale, of an emissive structure of this device;
• the figure 4 is a schematic perspective view of a support for emissive structures according to another embodiment of the present invention; and
• the figure 5 is a schematic plan view of an emissive structure according to another embodiment of the invention.

The device 10 for purifying a gaseous medium laden with particles forming the subject of the embodiment of the figures 1 to 3 is a free-standing device, which can be mounted on wheels. It has an overall rectangular parallelepiped configuration.

For the sake of highlighting its characteristic elements, this purification device has been shown very schematically in these figures.

The assembly of its various component parts has in particular not been shown in detail, as it is well known per se to those skilled in the art.

This purification device 10 generally comprises an electrostatic filtration chamber 11 and suction means 12 downstream of this electrostatic filtration chamber, to extract from the chamber the gaseous medium stripped of its particles.

In practice, this electrostatic filtration chamber 11 is, here, interposed between an inlet compartment 13 through which the gaseous medium laden with particles enters the device and more particularly into the electrostatic filtration chamber 11 and an outlet compartment 14, thanks to which the suction means 12 are housed and by which the gaseous medium stripped of its particles is discharged into the surrounding environment.

According to the rectangular parallelepiped configuration of the purification device 10, the inlet compartment 13 comprises a frame 15 carried by a bottom 16 and formed of four walls assembled at right angles, one of which, 17, is perforated to allow the gaseous medium to enter the device, here from below the electrostatic filtration chamber 11.

In the case of the present embodiment, the gaseous medium laden with particles thus enters the purification device 10, in a direction substantially perpendicular to that of flow in the filtration chamber 11.

Before entering this electrostatic filtration chamber, it passes through, here, a pre-filter 18 intended to retain large particles. This is, for example, a metal knit or stretched metal filter.

At the opposite end of the purification device 10, the outlet compartment 14 for the gaseous medium stripped of its particles comprises a box 19 in the shape of a rectangular parallelepiped, the upper wall 20 of which is perforated to allow this gaseous medium stripped of its particles to pass. .

The suction means 12, which are here in the form of a fan, are mounted in this box 19, at the level of the face of the latter opposite the perforated wall 20.

The gaseous medium thus flows horizontally in the inlet box 15 then vertically to the outlet of the purification device 10.

As can be seen on the figure 1 and 2 , the suction means 12 are arranged directly at the outlet of the electrostatic filtration chamber 11 and are in fluid communication therewith to suck in the gaseous medium.

This electrostatic filtration chamber 11 comprises, here, two supports 21 of emissive structures arranged in the passage formed by the electrostatic filtration chamber 11 between an inlet therein (after the prefilter 18) and an outlet thereof (just before the suction means 12).

On either side of these supports 21 of emissive structures are arranged collecting structures 22 designed to trap the particles contained in the gaseous medium charged with particles.

Each support 21 of emissive structures comprises, more precisely, a plurality of emissive structures 23 arranged in the passage, one after the other, between the inlet and the outlet of the electrostatic filtration chamber 11.

Each emissive structure 23 is in the form of a plate, preferably a blade, here five in number per support 21, designed to force the gaseous medium laden with particles to flow in the vicinity of the collecting structures 22.

Each blade 23 also comprises, at its periphery, points 26 directed towards the collecting structures 22.

It is, more precisely, as can be seen better on the picture 3 , of a blade 23 having, on either side of a central deflection surface 24, indentations 25 forming said points 26 between them.

This is, here, rounded indentations cut in a stainless steel plate so that the points of the two opposite edges of the blade 23 provided with these points 26 are staggered.

Each support 21 comprises two U-sections 27 assembled, parallel to each other and back to back, by four spacers 28 each welded to a corner of the U-section 27. It should be noted in this respect that the fourth spacer 28 is not visible in the figures.

Each blade 23 comprises, for its mounting on this support 21, a rod 29 welded to each of two opposite mounting edges 30 which extend generally perpendicular to the edges of the blades 23 provided with the points 26.

The U-sections 27 are provided, for receiving the rods 29, with passage openings 31 for these rods.

The maintenance in position on the support 21 of each of the blades is obtained, in the case of the present embodiment, by means of the interposition of a nested insulator 32, by complementarity of shapes (of square section), in an opening 31 and receiving, itself, a rod 29 of the blade 23.

Each rod 29 is, to do this, threaded and engaged in a central cylindrical hole of the insulator 32 and fixed by a nut (not visible in the figures and housed in a passage hole 36 of square section preceding this cylindrical hole in the insulator and ending before this last hole with a bearing surface for the nut), so that each blade is mounted with possibility of angular orientation in the electrostatic filtration chamber 11.

It will be noted here that in other embodiments, the insulator can also be protected by means of a bell and a counter-bell or deflectors, in the manner of what is described in the application for patent cited above ( WO 01/19525 ). This makes it possible in particular to avoid electrical bridges.

Each blade 23 forming an emissive structure is, here, brought to a cathodic voltage of the order of 10 kV by a circuit supplying a high voltage 33, housed in a control box 34 mounted, within the framework of this embodiment, in box 19.

For the trapping of the particles, each collector structure 22 comprises, in the context of the present embodiment, a metal knit in the form of a plate brought, here, to an anode voltage of the order of 5 kV, being connected to a circuit 35 providing a high voltage, which is also housed in the control box 34.

For their high voltage supply, the collector plates 22 can be mounted in a frame by means of rods passing through openings made in this frame and the interposition of insulators, in a manner similar to that provided for the blades 23 on their support 21. Therefore, this has not been shown in the figures, for the sake of simplification.

It will nevertheless be noted that the connection to the circuit 35 can be obtained, for example, with a leaf spring integral with the upper box 19 and in contact with a rod of the plate 22. The implementation of one or more of these blades can also allow to maintain the plate in position within the device and its placement and removal therefrom.

In the case of the central collector plates 22, they are held in place by their arrangement between the two supports 21 (their installation and removal is obtained by simple sliding).

Such provisions are not represented, for the sake of simplicity, on the figures 1 to 3 , but can easily be implemented by those skilled in the art based on the aforementioned explanations.

The purification device in accordance with the present invention, as described in particular with reference to the figures 1 to 3 , thus proves to be particularly flexible, in particular thanks to the mounting of the blades 23 on the supports 21, one independently of the other (and electrically isolated from each other on their support). This makes it possible in particular to orient each of the blades as desired, in particular to produce ozone having a germicidal effect on microorganisms of the virus and bacteria type. This production of ozone can be obtained by orienting the blades 23 perpendicular to the collector plates 22, while an orientation different from the perpendicular (the tips of the collector structures 22 are moved away) will stop or reduce this production of ozone.

Of course, the blades 23 are always oriented so as to form a non-zero angle with the plane of the collector plates 22 which extend parallel to one another, the blades 23 being themselves aligned according to a parallel alignment to these same planes.

It will also be noted that the edges of the blades 23 provided with the points 26, extend to the vicinity of the collector plates 22, leaving only a space remaining avoiding the formation of arcs in a position in which the blades 23 are extend perpendicularly to these collector plates 22 or, in practice, a space of the order of one millimeter for 1000V of voltage applied to the blade 23 corresponding.

In addition, negative ions produced by the ionization taking place in the electrostatic filtration chamber are also of interest in terms of the therapeutic effects that they can generate.

It will also be noted that the possibility of orienting the blades 23 makes it possible to play with the speed of the gas flow flowing in the electrostatic filtration chamber 11.

A door 37 is, moreover, provided to isolate the side collector plates 22 from the surrounding environment, while being able to access them to remove them from the purification device 10 with a view to cleaning them.

This device also proves to be easy to manufacture, for example from cutting and, where appropriate, bending of stainless steel plates.

Furthermore, such a device can also be easily implemented in already existing systems.

According to an inverse configuration (it would suffice to turn over the fan and move the pre-filter 18), the air to be treated could be sucked in from the top and be expelled from the bottom of the device. Such a configuration would advantageously find application in ventilation ducts.

It can be added that the device can operate vertically, as seen on the figures 1 to 3 , or horizontally.

Alternatively (see figure 4 ), it may be envisaged to implement, for example, two rows of emissive structures 23′, here plates, extending side by side, preferably parallel to one another, in the passage, with an arrangement in staggered from one row to the other. A single support 21′ is moreover provided in the context of this embodiment to carry these emissive structures 23′.

According to yet another embodiment of the emissive structures 23", shown in the figure 5 , the spikes 26" do not protrude from the periphery of each of the plates, but are formed inside the corresponding plate, by means of a longitudinal cut made therein in the vicinity of each of its longitudinal edges.

It is more precisely, on each side of the plate, a cutout forming two rows of rounded notches 25", facing each other and forming between them the points 26" directed towards the collecting structures. Each cutout is further formed so that the 26" tips of the two rows are staggered.

Of course, the present invention is in no way limited to the embodiments chosen and represented, but encompasses any variant within the reach of those skilled in the art.

In particular, the device according to the invention could comprise a UV radiation lamp arranged upstream of the entrance to the electrostatic filtration chamber 11 (for example in the box 15) to attract and kill insects, such as mosquitoes .

At the opposite end, a finishing filter, for example based on activated carbon, in metal knit or stretched metal, can also be implemented between the electrostatic filtration chamber 11 and the suction means 12.

Each collector structure can also comprise one or a succession of stretched metal plates instead of the metal knit or even be made from an alternation of metal knit and stretched metal plates.

Other voltages can also be considered for the emitting and collecting structures. In particular, it can be envisaged to bring, in a succession of stretched metal plates forming a collector structure, one plate out of two to a voltage of the order of 5 kV and to ground the following one. Generally, the voltages are chosen to be between 10 and 50 kV.

Depending on the voltage that it is decided to apply to the emitting and collecting structures, the circuit supplying a high voltage will of course supply a positive or negative high voltage.

Another possibility could be to bring one out of two emissive structures to a positive high voltage and the other to a negative high voltage, while the collecting structures would be grounded or a positive high voltage.

It will be noted, moreover, that a frame, made from sections, such as angle irons, can complete the device, for example for its mounting on wheels or the positioning of the central collecting plates on rails in the form of U to facilitate their sliding.

Many more than two emissive structure supports can also be envisaged.

In addition, each blade may, to increase the turbulence at the level of the aspirated flow, be twisted.

Claims (12)

1. Device (10) for purifying a particle-laden gaseous medium, including an electrostatic filtering chamber (11) having a passage for the particle-laden gaseous medium which extends between an inlet of this medium into the chamber (11) and an outlet thereof; a plurality of emitting structures (23) arranged in the passage, one after another between the inlet and the outlet of the chamber (11); on either side of these emitting structures (23), collecting structures (22) in the form of plates for collecting the particles; each emitting structure (23) being in the form of a plate including at the periphery thereof, tips (26) directed towards the collecting structures (22); characterised in that each plate of the emitting structures (23) is designed to force the particle-laden gaseous medium to flow in the vicinity of said collecting structures (23); each collecting structure (22) includes, for trapping the particles contained in the particle-laden gaseous medium, a metallic fabric and/or a series of drawn metal plates; and the device (10) includes suction means (12) fluidically connected to the outlet of the chamber (11) for extracting the gaseous medium cleared of the particles thereof from the chamber.
2. Device (10) according to claim 1, wherein at least one of the emitting structures (23) is orientably mounted in the electrostatic filtering chamber (11).
3. Device (10) according to claim 1 or 2, wherein each plate of the emitting structures (23) is in the form of a strip capable of being twisted.
4. Device (10) according to any one of claims 1 to 3, wherein each plate of the emitting structures (23) has, on either side of a central deflection surface (24), notches (25) forming said tips (26) therebetween.
5. Device (10) according to claim 4, wherein the tips (26) are disposed in staggered rows along two opposite edges of each plate of the emitting structures (23).
6. Device (10) according to claim 4 or 5, wherein the edges of the plates of the emitting structures (23) provided with the tips (26) extend up to in the vicinity of the collecting structures (22), only allowing a space preventing arc formation to remain, in a position wherein the plates of the emitting structures (23) extend perpendicularly to the collecting structures (22), parallel with one another.
7. Device (10) according to any one of claims 1 to 6, wherein each plate of the emitting structures (23) includes a rod (29) projecting onto each of two opposite mounting edges, for mounting the plate of the emitting structures (23) on a support (21).
8. Device according to claim 7, wherein the support (21) is in the form of a frame provided, for receiving each rod (29), an opening for the passage thereof.
9. Device (10) according to any one of claims 1 to 8, wherein each emitting structure (23) is carried to a high voltage, preferably to a voltage of the order of 10 kV.
10. Device (10) according to any one of claims 1 to 9, wherein each collecting structure (22) is carried to a high voltage, preferably to a voltage of the order of 5 kV.
11. Device (10) according to any one of claims 1 to 10, wherein the emitting structures (23) are aligned, according to an alignment parallel with the collecting structures (22).
12. Device (10) according to any one of claims 1 to 11, wherein each collecting structure (22) has a rectangular parallelepiped shape.

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