FR2830181A1 - FLOOR CLEANING METHOD AND APPARATUS - Google Patents

Abstract

The invention relates to a floor cleaning device comprising a motor fan (530) having an intake air inlet (530A) and a pressurised air outlet (530B), a container (591) that is used to collect solid or liquid particles and a cleaning head (540) which is provided with a tapered cavity (541) that is opened towards the bottom. An injection nozzle (551) is disposed on a lower part of the tapered cavity and is essentially tangential of the pressurised air. Said nozzle creates a vortex effect and the particles are extracted via a lateral window (561) without communicating with the air flow. An air outlet (571) which is formed through the large base of the tapered cavity (541) is in communication with the air inlet (530A) of the motor fan. The inventive floor cleaning device also comprises a slot (101) which, at the lower base of the tapered cavity (541) of the cleaning head (540), forms a radial projection of pressurised air. A laminar and non-rotational flow forms a screen between the ground and the vortex effect created inside the cavity at least at the periphery of the tapered cavity (541).

Description

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 The present invention relates to a method and an apparatus for cleaning floors.

 The invention relates more particularly to a floor cleaning method according to which air is injected tangentially under pressure into the lower part of a frustoconical cavity open downwards and having its small base oriented downwards, for creating an ascending cyclone by vortex effect within this cavity, particles of the ascending cyclone are extracted by at least one lateral particle extraction window disposed in the upper part of the frustoconical cavity, and the ascending air flow is extracted to reinject it under pressure and apply it tangentially to the lower part of the frustoconical cavity.

 A process of this type and a floor cleaner implementing this process are described in patent document EP 1 068 827 A2.

 In these known embodiments, the rotating movement of the air within a circular cavity increases the cleaning efficiency while facilitating the separation of the particles from the recycled air. The particles are separated from the transfer air by the centrifugal effect due to the cyclone itself, without the addition of an additional device. The circulation of cleaning air in a closed circuit and the trapping of dirt in a closed particle recovery receptacle help prevent particles from returning to the ambient atmosphere.

 Such a cleaning process is well suited for cleaning floors such as carpets or rugs with which the sole of a cleaning head can rest directly on the floor.

 On the other hand, in the case where it is advisable to clean smooth surfaces such as tiles, pavements or parquet floors, with which a cleaning device is preferably mounted on rollers or wheels and has one or more cleaning heads the sole of which is disposed at a low height from the ground, the tangential air flow creating a cyclone can sometimes have the result of chasing laterally larger waste instead of attracting it towards the center of the cyclone to integrate it into the updraft.

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 A floor cleaner with a tapered cleaning head, given its geometry, may also not perfectly clean the corners of the room.

 The present invention aims to remedy the aforementioned drawbacks and to make it possible to carry out an integral and effective floor cleaning capable of ensuring the complete suction of solid or liquid waste or dirt, according to an anti-allergy operation, with a cleaning head which can also rest directly on the floor, in particular for cleaning fibrous surfaces, such as carpets, or be located slightly raised above the ground, in particular for cleaning smooth surfaces such as tiles or parquet floors example.

 The invention also aims to allow the realization of universal cleaning devices, inexpensive, simple and compact design and capable of improving the cleaning capacity regardless of the nature of the floor and the geometry of the walls delimiting the area to be cleaned. .

 These aims are achieved by means of a floor cleaning process according to which pressure air is injected tangentially into the lower part of a frustoconical cavity open downwards and having its small base oriented downwards, to create by vortex effect an ascending cyclone within this cavity, particles of the ascending cyclone are extracted by at least one lateral window for particle extraction arranged in the upper part of the frustoconical cavity, and the ascending air flow is extracted to reinject it under pressure and apply it tangentially to the lower part of the frustoconical cavity, characterized in that part of the extracted air flow is withdrawn under pressure before its tangential reintroduction into the lower part of the frustoconical cavity to form the lower base of the frustoconical cavity a radial projection of pressurized air with a laminar and non-rotational flow forming at least at the periphery Erie of the frustoconical cavity a screen between the ground and the vortex effect created within the cavity.

 The presence of a screen with radial projection of pressurized air located between the ground and the tangential air injection creating the suction cyclone effectively prevents particles of waste located under a cleaning head from being removed. laterally

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 outwards, even if the cleaning head is in a slightly raised position relative to the ground, while retaining the updraft of the cyclone its capacity to entrain particles towards the extraction windows.

 Advantageously, an amount of air corresponding to approximately 20 to 30% of the extracted air flow reinjected under pressure is taken to form the radial projection of air under pressure with a laminar and non-rotational flow.

 The invention also relates to a floor cleaner comprising a support plate for an electric motor fan having a suction air inlet and a pressurized air outlet, a motor fan protection cover, at least one particle recovery receptacle solids or liquids and at least one cleaning head itself comprising a frustoconical cavity open downwards and having its small base oriented downwards, at least one first substantially tangential pressurized air injection nozzle disposed on a part bottom of the frustoconical cavity to create a vortex effect within this cavity and at least one first lateral window for extracting particles disposed in the upper part of the frustoconical cavity and without communication with the flow of air entrained towards the inlet of air intake, the first lateral particle extraction window communicating with the particle recovery receptacle, the first pressurized air injection nozzle communicating with the pressurized air outlet of the fan, and an air outlet formed through the large base of the frustoconical cavity being in communication with the air inlet of the fan , characterized in that it further comprises means for forming at the lower base of the frustoconical cavity of the cleaning head a radial projection of pressurized air with a laminar and non-rotational flow forming at least on the periphery of the frustoconical cavity a screen between the ground and the vortex effect created within the cavity.

 More specifically, the means for creating a radial projection of pressurized air comprises a radial air projection slot formed at the bottom of the cleaning head, under the

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 first injection nozzle, and supplied from the pressurized air outlet of the fan.

 The floor cleaner comprises vertical channels formed in the wall of the cleaning head for supplying from the outlet of pressurized air, on the one hand the first injection nozzle and on the other hand the radial projection slot air.

 According to a particular embodiment, the cleaning head defines a sole having at least one protrusion forming a rounded tip extending outward in the horizontal direction relative to the frustoconical cavity, at the base thereof.

 In this case, the underside of the projection of the cleaning head comprises an elongated groove formed in the central part of the projection and opening into the frustoconical cavity.

 The radial air projection slot made in the lower part of the cleaning head can be formed at the periphery of the sole of the cleaning head by taking on the external shape of this sole.

 According to a particular characteristic, the floor cleaner comprises a circuit for bypassing part of the pressurized air supplying the first injection nozzle and the radial air projection slot to form a horizontal flow of air directed towards the center of the frustoconical cavity in the elongated groove.

 According to a particular embodiment, which makes it possible to reduce the distance between the radial air projection slot and the underside of the sole of a cleaning head, the floor cleaner comprises an annular slot which is interrupted in the area of the frustoconical cavity where the elongated groove opens.

 According to another particular characteristic, the extreme part of the protrusion in the shape of a rounded point comprises a lower part forming the sole and delimiting a groove and extending under the extreme part of the elongated groove opposite the frustoconical cavity to delimit a passage creating by Coanda effect a tangential air flow in the elongated groove.

 The floor cleaner according to the invention may comprise a plurality of essentially tangential air injection nozzles under

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 pressure arranged in the same plane in the lower part of the frustoconical cavity above the means for creating a radial projection of air under pressure.

 The floor cleaner may also include several cleaning heads each equipped with a means for creating a radial projection of pressurized air disposed in the lower part of a frustoconical cavity under at least one first essentially tangential injection nozzle d under pressure.

 Other characteristics and advantages of the invention will emerge from the following description of particular embodiments, given by way of examples, with reference to the appended drawings, in which: - Figure 1 is a sectional view, essentially according to the line 1-1 of FIG. 2, of a floor cleaner according to a first embodiment of the invention; - Figure 2 is a sectional view, essentially along the line II-II of Figure 1; - Figure 3 is a bottom view of a floor cleaner according to a second embodiment of the invention; - Figures 4 and 5 are sectional views respectively along lines IV-IV and V-V of Figure 3; - Figure 6 is a bottom view of a floor cleaner according to a third embodiment of the invention; - Figure 7 is a sectional view along the line VII-VII of Figure 6; FIG. 8 is a view along arrow F of FIGS. 6 and 7, and FIG. 9 is a sectional view similar to that of FIG. 2 but applied to the floor cleaner according to the embodiment of FIGS. 6 to 8 .

 FIG. 1 shows an example of a floor cleaner implementing the invention, which comprises a cleaning head 540 associated with a tank 591 for recovering particles or waste, and with an electric fan 530 mounted on a plate of support 501 surmounting the cleaning head 540.

 The fan 530 is protected by a cover 503, the lower part of which is fixed to the plate 501.

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 Air inlets 535 can be made at the top of the cover 503, for example in the form of slots, to introduce cooling air flowing downward between the engine 530 and the cover 503. The cooling air of the motor is evacuated to the outside through orifices or notches 536 produced in the lower part of the cover 503 in the vicinity of the plate 501. A filter 537 can be disposed between, on the one hand, the air inlets 535 and a fan 531 for cooling the electric motor and, on the other hand, the body of the motor 530 to prevent dirt from accumulating between the motor 530 and the cover 504. Other embodiments of the means for cooling the motor 530 are however possible and the previous embodiment is given only by way of example.

de reposer sur le sol 10, notamment pour le cas où le sol 10 est constitué d'une surface fibreuse, telle qu'une moquette ou un tapis. Les galets G4 et G5 situés à l'arrière du nettoyeur de sol peuvent dans tous les cas reprendre les efforts exercés par le manche 504 articulé sur la partie arrière du nettoyeur de sol. A handle 504 is articulated on the rear part of the floor cleaner. Rollers G4, G5 (FIGS. 1 and 2) disposed at the rear of the floor cleaner make it possible to take up the forces exerted by the handle 504. At the front part of the floor cleaner, a roller G3 suspended by a stirrup 65 can be mounted in two different positions on a support 66 secured to the body of the cleaner or to the container 591 for recovering waste defining closed chambers. In a low position, the roller G3 makes it possible, with the rollers G4 and G5, to maintain the sole 502 of the cleaning head at a low height h with respect to the ground 10, in particular for the case where the ground 10 consists of a hard surface such as a tile. In a high position, the roller G3 is retracted and does not rest on the ground 10, which allows the sole 502 of the cleaning head

to rest on the floor 10, in particular for the case where the floor 10 consists of a fibrous surface, such as a carpet or a carpet. The rollers G4 and G5 located at the rear of the floor cleaner can in any case take up the forces exerted by the handle 504 articulated on the rear part of the floor cleaner.

 In the embodiment of Figures 1 and 2, the floor cleaner comprises a single cleaning head and has a footprint of essentially triangular shape with a rounded front part and of smaller dimensions and a rectilinear rear part to which is fixed the handle 504 and which rests on the ground 10 by the rollers G4 and G5. A steam application ramp 61, or where appropriate water or

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 cleaning product and a brush 507 can be arranged along the rectilinear rear face of the floor cleaner. The floor cleaner according to the invention is not however limited to the geometry of the example shown in FIGS. 1 and 2.

 The operation of the floor cleaner, and in particular the closed cleaning air circuit will now be described with reference to FIGS. 1 and 2.

 The cleaning air drawn in by the central air inlet 530A of the turbine 530C driven by the motor 530 is recycled through orifices 530B in two diametrically opposite transfer channels 531,532 located in the wall of the cleaning head 540. The cleaning air present in the transfer channels 531,532 is injected into the lower part of the frustoconical cavity, open downwards, of the cleaning head 540 by diametrically opposite nozzles 551,552. By the vortex effect, the particles present at ground level 10 are torn off and entrained by centrifugal force towards orifices 561, 562 for extracting particles located at the upper part of the side wall of the cleaning head 540 to penetrate into a or several closed chambers of the dirt collection tank 591, the closed chambers being isolated from the outside and from the main flow of cleaning air.

 A safety grid 582 forming a filter is mounted by fixing elements 586 on a plate 584 and is thus interposed in front of the suction inlet 530A of the turbine 530C to retain residual particles. However, the solid or liquid particles are essentially evacuated towards the extraction orifices 561, 562. The filter 582 can be annular or planar.

 In the case where the sole 502 of the cleaning head 540 does not rest directly on the ground 10, one or more rollers G3 being placed in the low position and cooperating with the rollers G4, G5 to maintain a ground clearance of a height h of the order of a few millimeters, for example from 2 to 5 mm, the present invention makes it possible to prevent the largest particles from being ejected laterally by the cyclone instead of being attracted to the center and being carried away by the current rising air.

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 To do this, part of the pressurized air flow sent downwards through the channels 531.532 is not evacuated by the nozzles 551.552 but is diverted towards an annular groove 101A which is located under the nozzles 551.552 in the wall of the cleaning head 540, the annular groove 101A opening into the frustoconical cavity 541 by an annular slot 101 located in the sole 502 below the nozzles 551, 552 being separated from the latter. The part of the pressurized air flow coming from the outlet 530B of the fan 530 and having circulated in the vertical channels 531,532 which does not escape through the injection nozzles 551,552 but is diverted towards the annular groove 101A can represent l 'around 20 to 30% of the total air flow and preferably around 25% of this total flow.

 The pressurized air 3 which enters the frustoconical cavity 541 through the annular slot 101 is injected radially into this cavity with a laminar and non-rotational flow forming at least on the periphery of the frustoconical cavity a screen between the ground 10 and the vortex effect 2 created within the cavity 541 by the air flow 1 tangentially injected by the injection nozzles 551,552.

 The width of the annular slot 101 can be of the order of a few tenths of a millimeter, for example from 0.4 to 0.8 mm. The annular slot 101 formed in the sole 502 is located as low as possible, for example at a distance between 1 and 2 mm from the underside of the sole 502. The thickness of material in the cleaning head between the annular slot 101 and the injection nozzles 551, 552 can also be between approximately 1 and 2 mm. In this way, the injection nozzles 551, 552, even when the cleaning head is raised a few millimeters from the ground 10, remain at a short distance from the ground 10, for example of the order of 6 to 12 mm, this which guarantees a good efficiency of entrainment of the particles by the vortex 2 created from the air stream 1 injected by the nozzles 551,552, despite the existence of the fluid partition 3 due to the radial projection through the annular slot 101.

 The air screen formed from the air 3 projected through the annular slot 101 contributes to bring towards the center of the frustoconical cavity 541 all the particles present on the ground 10, including the most

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 large and to allow easy suction of these particles by the upward pressure current 2 created by the vortex effect. The vortex 2 thus fully plays a role of suction of the particles upwards while being prevented from propagating downward to the level of the ground 10 by the air screen 3 projected radially by the annular slot 101.

 Various variant embodiments which aim in particular to improve the cleaning capacity in the corners of the rooms will now be described with reference to FIGS. 3 to 9.

 In these various embodiments, the cleaning head 540 comprises a sole 502 having at least one protrusion forming a rounded tip 600 extending outward in the horizontal direction relative to the frustoconical cavity 541, at the base of that -this.

This essentially triangular point 600 extends the sole to the front part of the floor cleaner to allow a better approach in the angles of the surfaces to be cleaned, for example in a corner defined by two walls 11 and 12. The end of the point triangular 600 is rounded to avoid damaging plinths or other vertical surfaces placed in the vicinity of the ground 10. The angle at the top of the triangular tip 600 can be for example between 450 and 900 and is advantageously of the order of 60 .

 The presence of a sharp protrusion 600 at the level of the sole of the floor cleaner does not fundamentally modify the cleaning head proper 540 which retains a vertical frustoconical cavity 541. However, the means for creating a fluid screen 3 are suitable to allow to bring back towards the center of the frustoconical cavity 541 the particles located on the ground under the protrusion 600 of the sole 502.

 More specifically, the underside of the protrusion 600 comprises an elongated groove 610 formed in the central part of the protrusion 600 and opening into the frustoconical cavity 541.

 In the embodiment of Figures 3 to 5, there is shown an elongated groove 610 of triangular shape oriented along the longitudinal axis of the sole 502, the tapered portion of the elongated groove 610 being located a short distance from the rounded tip of the outgrowth 600.

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 In FIGS. 3 to 5, it can be seen that the essentially annular slot 201 situated under the injection nozzles 551, 552 and situated in the wall of the cleaning head 540 to create a radial air jet forming a screen 3, is extended by a groove 210 which follows the shape of the protrusion 600 of the sole 502 and opens into the elongated groove 610, so that a pressurized air distribution slot is created with a laminar and non-rotational flow in an annular slot 201,210 which substantially matches the external shape of the sole 502.

 The slot 201 formed around the frustoconical cavity 541 is thus interrupted at the level of the protrusion 600 to be extended by the groove 210 which also receives pressurized air from the vertical channels 531,532 and is formed in the protrusion 600 of the sole 502 around the elongated groove 610 in order to open into the latter and expel towards the center of the frustoconical cavity 541 the particles located on the ground at the level of the elongated groove 610.

 At the tip of the protrusion 600, the groove 210 opens axially into the elongated groove 610 to allow an air jet 4 passing over the tip 622 of the front end 502A of the sole 502 to be directed horizontally towards the center of the frustoconical cavity 541 by driving the other air jets 3 introduced laterally into the elongated groove 610 from the groove 210.

 In the embodiment of Figures 6 to 8, a substantially annular slot 301 is formed in the wall of the cleaning head 540 all around the frustoconical cavity 541 substantially as in the embodiment of Figures 1 and 2. An essentially groove annular 301A receives the pressurized air flow from the vertical channels 531, 532 and feeds the slot 301 which opens radially into the frustoconical cavity 541 to emit a radial jet 3 forming a screen relative to the vortex 2.

 The elongated groove 610, which may have a simple rectangular shape, is formed along the axis of symmetry of the protrusion 600 in the shape of a rounded point, at the same level as the groove 301A and the slot 301, being separated of these. A channel 620 bypassing part of the pressurized air supplying the nozzles 551,552 and the annular slot 301 connects one of the vertical channels 531,532 or the groove

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 annular 301A to a small chamber 621 which is formed at the front end of the protrusion 600 and opens into the groove 610 to inject into it, by Coanda effect, pressurized air 4 which is directed into the groove 610 towards the center of the frustoconical cavity 541. The passage between the small chamber 621 and the elongated groove 610 is defined by the front end of the groove 610 and the free end 622 of a front part 502A of the sole (FIG. 7).

 The embodiment of FIGS. 6 and 7 is simple to manufacture and ensures sufficient entrainment of the particles located at the level of the protrusion 600 towards the center of the cavity 541.

 The embodiment of FIGS. 6 to 8 makes it possible to reduce the height of the sole of the floor cleaner and to bring the vortex effect 2 closer to the ground while retaining the presence of a fluid screen 3 at the periphery of the frustoconical cavity 541 and also retaining a tangential air current along the axis of the elongated groove 610 of the protrusion 600 in the direction of the center of the frustoconical cavity 541.

 In the embodiment of FIGS. 6 to 8, the annular groove 301A and the annular slot 301 are simply interrupted at the level of the elongated groove 610. In this way, the bottom wall 502A of the elongated groove 610 can be at the same level as the wall of the sole 502 defining the underside of the slot 301, which contributes to bringing the fluid screen 3 coming from the annular slot 301 closer to the ground while retaining the flow 4 returning in the elongated groove 610 towards the center of the cavity 541, the particles located at the level of the protrusion 600.

 Figure 9 is a view similar to that of Figure 2, but relates to the embodiment of Figures 6 to 8 with a protrusion 600 in the shape of a rounded triangular point formed in front of the floor cleaner. Given the presence of the elongated groove 610, the vertical channels 531 and 532 are arranged in angular positions slightly offset from the case of FIGS. 1 and 2. The numbers of vertical channels 531,532, of injection nozzles 551,552 and 561,562 extraction windows can naturally be different from two. In FIG. 9, the front roller G3 has not been shown. This can be achieved in different ways as soon as its position

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 does not interfere with the chamber 621 or the elongated groove 610. The roller G3 can thus for example be placed immediately in front of the chamber 621. It is also possible to implement at the front a pair of rollers arranged on both sides and d other of the elongated groove 610.

 The invention is not limited to a floor cleaner with a single cleaning head, but can also be applied to floor cleaners with several cleaning heads each comprising a frustoconical cavity. In this case, each cleaning head is equipped with a pressure air injection slot located in the lower part of the frustoconical cavity under the tangential pressure air injection nozzle (s). Each air injection slot ensures the radial projection of air so as to form a horizontal convergent laminar fluid screen. The radial air projection slots are formed at the periphery of the frustoconical cavities over most of the periphery thereof, but certain interruptions are possible as described above with reference to the embodiments of FIGS. 3 to 9.

Claims (15)

1. Floor cleaner comprising a plate (501) for supporting an electric fan (530) having a suction air inlet (530A) and an outlet for pressurized air (530B), a protective cover (503) of the fan motor (530), at least one receptacle (591) for recovering solid or liquid particles and at least one cleaning head (540) itself comprising a frustoconical cavity (541) open downwards and having its small oriented base downwards, at least a first essentially tangential injection nozzle (551) of pressurized air disposed on a lower part of the frustoconical cavity to create a vortex effect within this cavity and at least a first lateral window (561 ) of particle extraction disposed in the upper part of the frustoconical cavity (541) and without communication with the flow of air entrained towards the intake of aspirated air (530A), the first side window (561) of extraction of communicating particles with the particle recovery receptacle (591), the first pressurized air injection nozzle (551) communicating with the pressurized air outlet (530B) of the fan, and an air outlet (571) formed through the large base of the frustoconical cavity (541) being in communication with the air inlet (530A) of the fan motor, characterized in that it further comprises means for forming at the lower base of the frustoconical cavity ( 541) of the cleaning head (540) a radial projection of pressurized air with a laminar and non-rotational flow forming at least on the periphery of the frustoconical cavity (541) a screen between the ground and the vortex effect created at within the cavity.  2. Floor cleaner according to claim 1, characterized in that the means for creating a radial projection of pressurized air comprises a slot (101; 201; 301) for radial projection of air formed at the bottom of the cleaning head (540), under the first injection nozzle (551) and supplied from the outlet (530B) of pressurized air from the fan (530).  3. Floor cleaner according to claim 2, characterized in that it comprises vertical channels (531,532) formed in the wall of the <Desc / Clms Page number 14>  cleaning head (540) for supplying, from the outlet (530B) of pressurized air, on the one hand the first injection nozzle (551) and on the other hand the slot (101; 201; 301) radial air projection.  4. Floor cleaner according to any one of claims 1 to 3, characterized in that the cleaning head (540) defines a sole (502) having at least one protrusion forming a rounded point (600) extending towards the exterior in the horizontal direction relative to the frustoconical cavity (541), at the base thereof.  5. Floor cleaner according to claim 4, characterized in that the lower face of the projection (600) of the cleaning head (540) comprises an elongated groove (610) formed in the central part of the projection (600 ) and opening into the frustoconical cavity (541).  6. Floor cleaner according to claim 4 or claim 5, characterized in that the slot (201,210) for radial air projection is formed at the periphery of the sole (502,502A) and conforms to the external shape of the latter. .  7. Floor cleaner according to claim 5, characterized in that it comprises a circuit (620) bypassing part of the pressurized air supplying the first injection nozzle (551) and the slot (101; 301) of radial air projection to form a horizontal flow (4) of air directed towards the center of the frustoconical cavity (541) in said elongated groove (610).  8. Floor cleaner according to claim 7, characterized in that it comprises an annular slot (301) of radial projection of air which is interrupted in the region of the frustoconical cavity (541) where the elongated groove (610) opens. .  9. Floor cleaner according to claim 7 or claim 8, characterized in that the external part of the protrusion (620) in the shape of a rounded point comprises a lower part (502A) forming a sole and defining a groove (621) and extending under the extreme part of the elongated groove (610) opposite the frustoconical cavity (541) to delimit a passage creating by Coandà effect a stream of air (4) tangential in the elongated groove (610).  10. Floor cleaner according to any one of claims 1 to 9, characterized in that the means for creating a radial projection <Desc / CRUD Page number 15>  pressurized air is supplied from the pressurized air outlet (530B) of the fan motor (530) with an amount of air corresponding to approximately 20 to 30% of the pressurized air flow supplied to said outlet ( 530B).  11. Floor cleaner according to any one of claims 1 to 10, characterized in that it comprises rollers or rollers (G3, G4, G5) making it possible to selectively maintain a sole (502,502A) of the head. cleaning (540) at a short distance (h) from the ground without contact with it.  12. Floor cleaner according to any one of claims 1 to 11, characterized in that it comprises a plurality of injection nozzles (551,552) essentially tangential of air under pressure arranged in the same plane in the lower part of the frustoconical cavity (541), above the means (101; 201; 301) for creating a radial projection of air under pressure.  13. Floor cleaner according to any one of claims 1 to 12, characterized in that it comprises several cleaning heads (540) each equipped with means (101; 201; 301) for creating a radial projection pressurized air disposed in the lower part of a frustoconical cavity (541) under at least one first nozzle (551) for essentially tangential injection of pressurized air.  14. Soil cleaning method according to which pressure air is injected tangentially into the lower part of a frustoconical cavity open downwards and having its small base oriented downwards, to create an ascending cyclone by vortex effect within this cavity, particles of the ascending cyclone are extracted by at least one lateral particle extraction window disposed in the upper part of the frustoconical cavity, and the ascending air flow is extracted to reinject it under pressure and apply tangentially to the lower part of the frustoconical cavity, characterized in that part of the extracted air flow is re-injected under pressure before its tangential reintroduction into the lower part of the frustoconical cavity to form the lower base of the cavity frustoconical a radial projection of pressurized air with a laminar and non-rotational flow forming at least on the periphery <Desc / Clms Page number 16>  from the frustoconical cavity a screen between the ground and the vortex effect created within the cavity.  15. The method of claim 14, characterized in that an amount of air is taken corresponding to about 20 to 30% of the extracted air flow reinjected under pressure, to form said radial projection of air under pressure with a laminar, non-rotational flow.