Brushing – scrubbing – and general cleaning – Machines – With air blast or suction
Reexamination Certificate
2000-01-14
2001-12-25
Till, Terrence R. (Department: 1744)
Brushing, scrubbing, and general cleaning
Machines
With air blast or suction
C015S327200, C055S456000
Reexamination Certificate
active
06332239
ABSTRACT:
TECHNICAL FIELD
The present invention concerns a device for collecting dirt intended to equip a vacuum cleaner.
PRIOR ART
In a conventional manner, there is provided, in this type of appliance, between the suction opening which will be termed “floor nozzle” in the remainder of this document and the suction motor, a bag for recovering dirt. This bag constituted in part of a material that is permeable to air, called media, performs on its internal surface the filtration of the gaseous fluid while retaining the solid particles that it contains. When it is full and/or plugged, this bag, generally of paper, sometimes of fabric, must be either replaced or emptied and cleaned by the user. The drawbacks connected with this operation, which are less acceptable as they are more frequent, can relate to its cost, but also to the unpleasantness occasioned by the removal, the handling and the reinstallation of the bag in the body of the appliance.
During filling of this bag, this latter becomes less and less permeable to air: pores of the media become blocked little by little with arrival of particles having small dimensions corresponding to the size of the pores creating the plugging which has been mentioned above. This plugging is translated into an increase in the loss of pressure in the passage of the bag, i.e. an increase in the pressure difference which exists to one side and the other of the media. After a prolonged period of use of the vacuum cleaner furnished with the same bag, a plugging appears and is thus amplified. It affects the vacuuming conditions in which there are assured the detachment of the particles in the zone in contact with the floor to be cleaned, that of the floor nozzle, the transport of said particles toward the bag but also the operating speed of the motor: this plugging provokes a drop in the flow rate, consequently degrading the effectiveness of the dust removal, while the speed of the motor increases, diminishing, by this fact, its useful life.
There are also known vacuum cleaners furnished with filtration means called cyclonic, particularly in the industrial field. Such devices permit a reduction in the frequency of intervention on the filters situated downstream of said means, if not being able to always dispense therewith completely. They act as true pre-filters. Naturally, the more effective this pre-filtration, i.e. having the capacity to collect particles of small size, the filters situated downstream thereof must be replaced less frequently. There flow therefrom vacuuming conditions which are more constant over time and thus more favorable at the same time to the useful life of the motor and the effectiveness of the dust removal.
In a first type of vacuum cleaner marketed by the NOTETRY Company, under the tradename DYSON, air loaded with dust is introduced tangentially under the upper cover of a frustoconic body oriented toward the bottom and opening into a lower container. In this body, air thus follows a helical descending path projecting solid particles against the internal face of the conical wall, these particles then falling by gravity along the wall into the container. At the end of the spiral, the air freed of solid particles travels back up along a central column and passes through a vertical tube passing through the center of the cover. The document WO96/21389 describes a more developed vacuum cleaner of this type having two cyclones provoked by two concentric chambers.
The particles which are the finest and thus very often the lightest have a tendency with regard thereto to be entrained by the flow, the centrifugal forces referred to above then only playing, with respect to said particles, a secondary role with respect to the entrainment forces. These particles are only recovered downstream of the device by means for example of pleated filters.
There exists numerous variants of such devices such as those presented in U.S. Pat. No. 3,925,045, utilizing several truncated cones, oriented toward the bottom, nested vertically in one another. More precisely, the small diameter of the lower part of a cone is slightly greater than the large diameter of the upper part of the following lower cone in such a manner as to leave between them a circular passage for dust pinned against the periphery by a cyclonic current induced by a tangential introduction.
The dust container must itself also be emptied regularly. This intervention being able to be found distasteful, is common to give the dust container large dimensions. It is necessary however to note that the fact of retaining a large quantity of dust during long periods promotes bacterial and/or microbial development within this storage zone.
It can also appear judicious to conceive of a system which permits easier and more regular removal with a smaller container of collected dirt. This will have in fact as an advantage to limit the size of the device, size which, in the case of the devices mentioned above, is very detrimental to the general ergonomics of the appliance (weight, maneuverability . . . ).
There will also be found in the prior art devices, such as that described in the patent application EPO 815 788, with a cyclonic centrifuging of the solid particles of which the device for introduction of dust, for example a helical tube, differs substantially from the prior systems. The filtration remains a cyclonic filtration to the extent where the flow is of the same type as that previously described. The originality resides above all in the fact that fine dust is captured due to the accumulation of electric charges, generated upon passage of solid particles into the introduction device, along external walls of this latter which the material forms, for the use, the object of a careful selection. The objective here is to improve the effectiveness of the pre-filtration of the conventional cyclones. This configuration remains however voluminous.
In addition, all of the devices have in addition as an inconvenience that they generate substantial pressure losses.
There is also known, in certain particular military applications, pre-filtration systems different from cyclone systems, called GD Systems in the remainder of the document: air is introduced into a tube which contains a screw positioned, on the axis of the tube, at one extremity of this latter, termed inlet or injection. It is of an exterior diameter substantially smaller than the diameter of the internal wall of the tube (from 20 to 60% smaller). Its role is to place the air in rotation and to centrifuge the solid particles in order to press them on said internal wall. In the extension of the extremity of the screw, on the same axis as that of the tube and of the screw, there is disposed at a certain distance another tube, called evacuation, always contained in the preceding tube, with a diameter equal to or less than the exterior diameter of the screw which assures the delivery of a certain proportion of the introduced dust removal air. In the space separating the external wall of the internal tube from the internal wall of the external tube there is arranged an adjoining exhaust which evacuates the remaining portion of the air, loaded, as regards it, with solid particles. In this type of application the already dirty air delivered by the adjoining exhaust is rejected sometimes directly to the outside.
This configuration is not however adapted to the conditions imposed by a utilization within a vacuum cleaner. In particular, the flow rates, the pressure drop levels, the passage cross sections and thus the sizes, the variety of dirt to be treated (which can be present, in the case of the vacuum cleaner, in the form of dirt which is fibrous, powdery, bread crumbs . . . ) differ greatly from a military to another household application.
The present invention relates to a pre-filtration device applied to the household field which offers the same advantages in terms of results and filtration quality as the devices previously described, while reducing the size, and limiting the pressure losses.
In addition, the structure and arrangement of the consti
Dubos Roland
Fleurier Vincent
Thery Marc
Browdy and Neimark
Seb S.A.
Till Terrence R.
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