FR2806318A1 - FILTRATION DEVICE FOR FITTING A VENTILATION AND / OR HEATING AND / OR AIR CONDITIONING APPARATUS, PARTICULARLY FOR A MOTOR VEHICLE - Google Patents

Abstract

Filtration device intended to equip a ventilation and / or heating and / or air conditioning apparatus, in particular for a motor vehicle, comprising a frame (12) at least partially surrounding a filtering medium (11): the frame (12) is made of flexible plastic and fixed to the filter medium (11) by overmolding; it comprises two side walls (13, 14) of small thickness, the internal faces of which are provided with thickeners (15) surrounding the longitudinal edges of the filtering medium (11).

Description

"Filtration device intended to equip a ventilation device and / or

  heating and / or air conditioning, in particular for a motor vehicle "The subject of the present invention is a filtration device intended to equip an aeration and / or heating and / or air conditioning apparatus, in particular

for motor vehicle.

  The object of the invention is to provide a filtration device capable of being deformed either temporarily during its insertion or removal into an apparatus, or permanently to take account of a non-planar shape of its sound.

housing in the device.

  According to the invention, a filtration device intended to equip a ventilation and / or heating and / or air conditioning apparatus, in particular for a motor vehicle, comprising a frame at least partially surrounding a filtering medium, is characterized in that the frame is made of flexible plastic and

  attached to the filter media by overmolding.

  Advantageously, the filtering medium comprises a non-woven mat

made of a carded veil.

  Preferably, the card web forms a single ply.

  Advantageously, the filtering medium comprises a grid.

  Advantageously, the filtering medium comprises means for adsorption of

  gases placed between the grid and said nonwoven mat.

  Preferably, the adsorption means comprise a flexible fabric of

activated carbon.

  Advantageously, said adsorption means comprise a bed of

activated charcoal.

  Preferably, a nonwoven mat consisting of a card web is

  disposed on either side of the adsorption means.

  Advantageously, a grid is arranged on either side of the filter medium. Preferably, the nonwoven mat is based on long fibers, the

  length is preferably at least 38 mm.

  Advantageously, said long fibers have an average diameter

equal to or greater than 10 pm.

  Preferably, said long fibers are made of thermoplastic material.

  Advantageously, said long fibers are polypropylene fibers.

  Advantageously, the filter medium is pleated.

  Preferably, the plastic of the frame is a material

flexible thermoplastic.

  Advantageously, the plastic material of the frame is a thermoplastic elastomer. Preferably, the frame comprises two thin side walls, the internal faces of which are provided with extra thicknesses surrounding the

  longitudinal edges of the filter media.

  Advantageously, the side walls are connected at one end by a transverse facade provided, on the inside, with sealing means and, on the side

  outside, gripping means.

  Preferably, the side walls are connected at one end by a

  sealing lip overmolded on the transverse edge of the filter medium.

  Advantageously, the side walls are provided externally with a

guide rail.

  The filtration device according to the invention is thus advantageously in the form of a flexible cassette capable of being temporarily deformed in all directions during its insertion, or removal, in an aeration and / or heating and / or air conditioning, which considerably facilitates the corresponding operations, especially when accessibility to the housing of the filtration device is generally

not easy.

  Thanks to the constitution of the filtration device according to the invention, the assembly of the different parts of it can be carried out without the use of solvent or glue while obtaining an excellent seal between the frame

  and the different active parts of the filtration device.

  The flexibility of the frame advantageously allows a tight assembly to

  the periphery thereof without the need for a seal.

  In addition, the flexibility of the frame helps prevent and absorb vibrations and noises at the level of the filtration device as well as in the duct.

where it is placed.

  Other characteristics and advantages of the invention will appear in the

  description below of an exemplary embodiment, with reference to the drawings

  attached in which: - Figure 1 is a schematic perspective view of a filtration device according to the invention; - Figure 2 is a partial view similar to that of Figure 1, according to the

  arrow Il of FIG. 1, slightly from below with respect to FIG. 1.

  The filtration device 10 comprises a filtering medium 11 forming a particle filter, formed from a nonwoven mat 24, FIG. 2, consisting of a card web

  in a single tablecloth. The filter medium 11 is pleated.

  Said nonwoven mat 24 is based on long fibers the length of which is preferably at least 38 mm. Said long fibers have an average diameter of 10 µm or more. Said fibers are made of material

  thermoplastic and, in practice, polypropylene.

  The nonwoven mat 24 is associated with a grid 25, for example made of polypropylene. This is placed downstream from the direction of

  air circulation in the filtration device 10.

  The filter medium 11 can be associated with two grids, pleated.

  This or these grids are joined or not to the nonwoven mat 24 when they are joined to said mat, this joining, which may be only partial, is obtained for example by ultrasonic welding, by bonding, by

  mechanical consolidation, in particular with a water jet, or other.

  The filtration device 10 can constitute a particulate filter, or a so-called combined filter, that is to say both a particulate filter and a gas arresting filter.

  harmful. In this case, gas adsorption means are added.

  Said gas adsorption means may comprise a bed of activated charcoal, or a flexible carbon fabric pleated in the same way as the medium.

filter 11.

  A flexible frame 12 is provided to support the various constituents of the

filtration device.

  The frame 12 comprises two side walls 13,14 of small thickness, the internal faces of which are provided with extra thicknesses 15 surrounding, by overmolding, the longitudinal edges of the filter medium 12, here the V-shaped ends of the pleats of the pleated filter medium 11; a partial cutaway of the side wall 14, Figure 1, allows to see the overmolding of the ends of the folds by the

extra thickness 15.

  On one side, known as the front side, the side walls 13, 14 are connected, at one of their ends, by a transverse wall called a transverse facade 16 which projects, in height and in width, relative to the side walls 13, 14 and the filter medium 11, so that a peripheral rim 17 is defined which is adapted to cooperate in sealing with the edge of an introduction opening of the device

  10, which includes the device to be packed.

  As transversely, an additional thickness 15, coming from the internal face of the transverse facade 16, surrounds, by overmolding, the transverse edge of the filtering medium 11; here, the transverse edge of the filter medium 11 is that of the narrow partition 18, generally horizontal, which extends the last V-fold towards the transverse facade 16; of course, the additional thickness 15 on the facade side 16 is extended laterally along the internal face of the side walls 13, 14 so as to also concern the longitudinal edges of said narrow partition 18. On its external face, the transverse facade 16 is provided with

  gripping means, such as a tongue 20 for example, FIG. 2.

  Here, on the side opposite to that where the transverse facade 16 is placed, a sealing lip 21 covers by overmolding the transverse edge of a narrow partition 19 which, like the narrow partition 18, is generally horizontal and extends the last V-fold of the filter medium 11; this sealing lip 21 is intended to cooperate in sealing with the bottom of the housing of the device to be filled; of course, it extends laterally along the extra thicknesses 15

  which cover the longitudinal edges of the narrow partition 19.

  In the example shown, the side walls 13, 14 are provided externally with a guide rail 22, 23 facilitating the installation of the filtration device in the housing which internally has grooves adapted to

receive said rails.

  The overmolding of the filtering medium 11 with a flexible thermoplastic material, with properties comparable to those of vulcanized rubber, will allow the deformation of the filtration device 10 which of course

  will depend on the material used and the distribution of the different thicknesses.

  The deformation of the filtration device 10 is allowed by that, natural thanks to the folds, of the filtering medium 11 and by that of the frame 12, in particular of its side walls 13, 14 capable for example of being deformed in their plane by creating waves therein. or undulations which do not disturb the deformation of the

  filter medium 11 in directions perpendicular to that of the folds.

  The overmolding operation, advantageously by injection, allows, as we have seen, the integration of particular functions such as sealing, guiding, gripping; others can be provided such as fixing by

clipping, for example.

  Different materials can be overmolded concomitantly, these

  having different properties depending on the constraints required.

  With regard to materials, good results have been obtained with thermoplastic elastomers such as that sold under the brand MULTIFLEX by the company MULTIBASE, or that sold under the brand

  SANTOPRENE by the company Advanced Elastomer Systems, AES.

  Thanks to the constitution thus described of the filter, it has interesting flexibility characteristics which allow it to be bent momentarily, or even to twist, in order to more easily introduce the filter into a heating and / or ventilation device and / or air conditioning of a motor vehicle, or extracting it. This is particularly advantageous when, as is very often the case, accessibility to the filter housing is difficult.

  The production of the nonwoven mat 24 can be carried out as follows.

  Polypropylene fibers with a fineness of 1.7 dtex (diameter 14pm)

  cut to a length of 40 mm are introduced into a mixer.

  The fiber mixture obtained is then introduced into a demotor and then into a storage silo before being carded by means of a wool type card with double comber equipped with a jumble type of pell-mell in order to obtain

an isotropic carding veil.

  The veil is, at the end of the card, introduced into a condenser to form

a tablecloth.

  The parameters of the card and the condenser are chosen so as to obtain a sheet having a surface mass of approximately 20 to approximately 150 g / m2. The tablecloth is placed on a carpet and then consolidated by an operation of

hydraulic tying.

  The hydraulic tying operation consists of passing very thin jets of water under high pressure through the rotary table.

(40 to 200 bars).

  By bouncing on the drum, the water jets cause knotting of the fibers, giving the tablecloth significant mechanical resistance without

  as much to increase, consequently, the density.

  After passing through a drying tunnel, the sheet is rolled up.

  The ply is then taken up again to undergo a pleating operation.

  With a 0.84 mm thick sheet, we were able to form a filter

  having a surface mass of 66 g / m2 and a density of 0.07.

  To test the efficiency of the filter thus produced, it was placed across a vein of section equal to 100 cm2, traversed by a stream of air

  charged with particles at a speed of 20 cm / s.

  The particles correspond to a powder called "fine SAE powder" which is defined by the standard of the United States of America, reference SAE J 726 / ISO 5011.

  The particle concentration is 100 mg / m3.

  We note, on the one hand, that the pressure drop across the filter is not,

  under these conditions, only 14 Pa and, on the other hand, the efficiency reaches 80%.

Claims (20)

  1. A filtration device intended to equip a ventilation and / or heating and / or air conditioning apparatus, in particular for a motor vehicle, comprising a frame (12) at least partially surrounding a filtering medium (11), characterized by the fact that the frame (12) is made of flexible plastic and fixed to the   filter media (11) by overmolding.   2. A filtration device according to claim 1, characterized in that the filtering medium (11) comprises a nonwoven mat (24) consisting of a card web. 3. A filtration device according to claim 2, characterized in that   the card web (24) forms a single sheet.   4. filtration device according to one of claims 1 to 3, characterized   by the fact that the filtering medium (11) comprises a grid (25).   5. filtration device according to claims 2 and 4 taken   jointly, characterized in that it comprises means for adsorption of   gases placed between the grid (25) and said nonwoven mat (24).   6. A filtration device according to claim 5, characterized in that   the adsorption means comprise a flexible fabric of activated carbon.   7. A filtration device according to claim 5, characterized in that   said adsorption means comprise a bed of activated charcoal.   8. filtration device according to one of claims 5 to 7, characterized   by the fact that a non-woven mat consisting of a card web is arranged   on either side of the adsorption means.   9. filtration device according to one of claims 4 to 8, characterized   by the fact that a grid is arranged on either side of the filter medium (11).   10. A filtration device according to any one of claims 2 to 9,   characterized in that the nonwoven mat (24) is based on long fibers   the length of which is preferably at least 38 mm.   11. A filtration device according to claim 10, characterized in that said long fibers have an average diameter equal to or greater than pm.   12. Filtration device according to one of claims 10 or 11,   characterized by the fact that said long fibers are made of thermoplastic material. 13. A filtration device according to claim 10, characterized in that said long fibers are polypropylene fibers.   14. filtration device according to one of claims 1 to 13,   characterized in that the filter medium (11) is pleated.   15. Filtration device according to one of claims 1 to 14,   characterized in that the plastic material of the frame (12) is a material flexible thermoplastic.   16. A filtration device according to claim 15, characterized in that   that the plastic of the frame (12) is a thermoplastic elastomer.   17. A filtration device according to one of claims 1 to 16,   characterized in that the frame (12) comprises two side walls (13,14) of small thickness, the internal faces of which are provided with thickeners (15)   surrounding the longitudinal edges of the filter medium (11).   18. A filtration device according to claim 17, characterized in that the side walls (13,14) are connected at one end by a transverse facade (16) provided, on the inner side, with sealing means (17) and, side   outside, gripping means (20).   19. A filtration device according to one of claims 17 or 18,   characterized in that the side walls (13,14) are connected at one end by a sealing lip (21) overmolded on the transverse edge of the media filter (11).   20. A filtration device according to one of claims 17 to 19,   characterized in that the side walls (13,14) are provided   externally of a guide rail (22,23).