EP1618824B1

EP1618824B1 - Domestic vacuum cleaner

Info

Publication number: EP1618824B1
Application number: EP20040425538
Authority: EP
Inventors: Silvano Fumagalli
Original assignee: Candy SpA
Current assignee: Candy SpA
Priority date: 2004-07-20
Filing date: 2004-07-20
Publication date: 2007-10-31
Anticipated expiration: 2024-07-20
Also published as: EP1618824A1; DE602004009782D1; DE602004009782T2

Description

The present invention relates to an improved domestic vacuum cleaner.
As is known, vacuum cleaners substantially comprise a box-shaped body and a fan coupled to an electric suction motor connected to an intake duct for air containing dust and and/or dirt. For domestic cleaning, therefore, a vacuum cleaner is used in which the flow of air containing dust, brought about by the motor/suction unit, passes through a filter, for instance a diaphragm filter (normally in the form of a bag) able to retain and separate the solid particles contained in the suctioned flow of air. The dust contained in the suctioned flow of air is therefore separated by the filter so as to enable clean air to be discharged from the vacuum cleaner via slots provided appropriately on the vacuum cleaner body.
However, the diaphragm filter interposed between the intake duct and the motor/suction unit generates a substantial loss of load in the suction circuit and consequently reduces the suction capacity of the vacuum cleaner at the same motor power. In practice, the drawback of this vacuum cleaner lies in the fact that consumption is the greater, the higher the degree of filtration required, as the diaphragm filter is an obstacle to the flow of air and causes substantial losses of load which are the greater, the more dust has accumulated in the filter.
A further drawback of this vacuum cleaner lies in the fact that the diaphragm filter needs to be replaced regularly since, as a result of the dust that accumulates during use, it tends to generate an increasing resistance to the flow of air, entailing the generation of a smaller vacuum at the suction mouth and therefore a deterioration of the performance of the vacuum cleaner.
To resolve these problems, fluid-bath vacuum cleaners have recently been developed and comprise a box-shaped body having a collection tank adapted to contain a fluid, a suction duct for cleaning operations and a motor /suction unit within the body in fluid communication with the tank.
The tank contains a fluid, generally water, to which the air flow containing dust is caused to bubble under pressure so as to obtain an extraction in water of the dust contained in the suctioned air flow.
In comparison with conventional vacuum cleaners, the suction power remains unchanged over time as there are no filters or filter bags with the result that efficiency and running costs are more limited.
Manufacturing costs are, however, high as a high-power motor/suction unit is required and the presence of water means that gaskets, protection devices and the like are needed.
Although vacuum cleaners of the above-mentioned type are satisfactory from a practical point of view, they have the serious drawback that the air purification fluid may flow back into the suction path downstream of the tank and/or be conveyed by the purified air along this path.
Use therefore has to be made of leak-tight electric motors, whose cost has a substantial impact, however, on the final price of the vacuum cleaner.
A vacuum cleaner according to the preamble of claim 1 is disclosed in JP 2001286422 .
In view of the prior art described above, the object of the present invention is to provide a vacuum cleaner having structural and operational features able to obviate the drawbacks described above with reference to vacuum cleaners of the prior art.
A further object of the present invention is to provide a vacuum cleaner in which the tank for the fluid responsible for extracting the dirt is separate from the motor/suction unit and which is therefore easier and more practical for the user to handle.
A further object of the present invention is to provide a vacuum cleaner which is economical and functional, which enables efficient filtration of the suctioned air, separating it from dust and dirt particles and from droplets of fluid prior to its discharge.
This object is achieved, in accordance with the present invention, by a vacuum cleaner as claimed in claim 1.
As a result of the present invention, it is therefore possible to provide a highly efficient domestic vacuum cleaner with a minimum absorbed power, compact dimensions and a high particle accumulation capacity.
The characteristic features and advantages of the present invention are set out in the following detailed description of a practical embodiment thereof, shown by way of non-limiting example in the accompanying drawings, in which:

Fig. 1 is a diagrammatic view, in section, of an embodiment of the vacuum cleaner of the present invention;
Fig. 2 is a view in cross-section along the line II-II of the tank associated with the vacuum cleaner of Fig. 1;
Fig. 3 is a top view of the tank associated with the vacuum cleaner of Fig. 1;
Fig. 4 is a diagrammatic side view of the tank of the vacuum cleaner of Fig. 1;
Fig. 5 is a view, in section, of a detail of the vacuum cleaner;
Fig. 6 is a view, in section, of a further detail of the vacuum cleaner of Fig. 1.

The vacuum cleaner 1 comprises a body 2 with which a tank 3 is associated.
The body 2 of the vacuum cleaner 1 comprises a filtration suction unit 2A comprising a container 4 which may be removed by extraction from the body 2, a motor/suction unit 5, a filter-holder 6 disposed upstream of the motor/suction unit 5 and an air discharge path 7 disposed downstream of the motor/suction unit 5.
In the following description, in order to ensure an improved and constant dust capture efficiency and ability, even of very fine dust, which is very often the cause of allergies, the embodiment provided with an axial cyclone or volute is proposed as the best embodiment of the filtration suction unit 2A.
Alternatively, it is possible to use any other type of known filtration suction unit which is more economic to produce than the axial cyclone or volute.
The container 4 takes the practical form, in a preferred embodiment, such as the embodiment of Fig. 1, of a body with a section of frustoconical type: it is provided laterally with an inlet opening 8 to which dirt and dust collection tools (tubes, brushes, crevice tools, etc.), of known type and not shown in the drawings, are adapted to be connected, comprises a top 9 adapted to divide the container 4 from the motor/suction unit 5 and also comprises, at the bottom, a base 10 adapted to collect the dust residues.
A generically cylindrical duct 11 (which is in practice slightly conical to facilitate moulding operations) which is connected in a known manner with the filter- holder 6 extends coaxially to and within the container 4.
The motor/suction unit 5, of substantially known type, comprises an electric motor adapted to cause the rotation of a fan adapted to generate the vacuum within the container 4 which gives concrete shape to the operation of the vacuum cleaner 1. The motor/suction unit 5 is supported by a base 12 which acts as a dividing wall between this motor/suction unit 5 and the discharge path 7.
The filter-holder 6 internally comprises a filter 6A which, in a preferred embodiment, takes the form of a filtration member of star-shaped type. This filter 6A may be readily removed by extraction from the filter-holder 6 so as to enable periodic cleaning operations.
A person skilled in the art may of course substitute other filters equivalent in structural and/or operational terms for this star-shaped filter 6A.
The air suctioned by the motor/suction unit 5 therefore enters the container 4 in a tangential direction (arrow A) via the inlet opening 8 and descends with a swirling movement (arrow B) into the frustoconical body of the container 4. In this way, the coarser particles contained in the suctioned air are deposited on the base 10 of the container 4 and the partially purified air rises back towards the centre (arrow C) of the frustoconical body in order to flow into the central duct 11.
A volute or cyclone (not shown), which provides the essentially axial flow of air in the duct 11 with a swirling movement, is rigidly housed in the central duct 11 and secured, for instance, by plastic thermowelding, adhesion or simply by pressure.
As a result of this swirling movement, the residual dust contained in the flow of air suctioned by the motor/suction unit 5 is centrifuged outwardly in a peripheral ring.
The separation of the peripheral portion of the flow of air from the central portion takes place within the duct 11, more particularly downstream of the cyclone, this central portion thus being able to flow freely through the star-shaped filter 6A. The dust contained in the peripheral portion of the flow of air gradually accumulates on the walls of the cyclone and tends to collect, under the effect of gravity, towards the bottom of the cyclone, and is deposited on the base 10 of the container 4.
The accumulation of dust in the star-shaped filter 6A is therefore substantially reduced. It will be appreciated that this container 4 has to be emptied periodically by the user.
The flow of air output from the apex of the cyclone 11 and which passes through the filter 6A is thus conveyed (arrows D) towards the motor/suction unit 5.
The air output from the motor/suction unit 5 (arrows E) is then deflected by a deflector 13 contained in the air discharge chamber 7. The purpose of the deflector 13 is to deflect the air discharged from the motor/suction unit 5 downwards. In substance, the deflector 13 conveys the air discharged from the motor/suction unit 5 towards the base 12.
In the embodiment shown in Fig. 1, the deflector 13 is symmetrical with respect to the vertical axis X-X of the motor/suction unit 5 and, in particular, the deflector 13 comprises a first portion 14 which extends externally of the motor/suction unit 5 and a second portion 15 which extends parallel to the vertical axis X-X of the motor/suction unit 5.
The body 2 of the vacuum cleaner 1 further comprises an outlet opening 16 adapted to bring the motor/suction unit 5 into fluid communication with the tank 3 via the discharge path 7. The tank 3 internally contains a container 3A which may be removed by extraction from the tank 3. The container 3A is adapted to collect the residual dust contained in the flow of air discharged by the motor/suction unit 5.
The container 3A is adapted to be filled to a predetermined level L with a fluid 17, for instance water, possibly mixed with deodorant, sanitising or like products.
A sealing gasket 18, for instance of rubber, is advantageously mounted on the peripheral edge of the outlet opening 15 of the body 2 and is adapted to prevent the fluid from gaining access to the motor/suction unit 5 and/or escaping from the container 3A.
The container 3A, which is partially filled with the fluid 17 as described above, is therefore in direct fluid communication with the motor/suction unit 5 by way of means for reducing the speed of the air discharged by the motor/suction unit 5. These means take the form in practice of a diffusing or diverging duct 19 whose free end portion 19A is disposed above the free surface L of the fluid 17.
The duct 19 is therefore in fluid communication with the motor/suction unit 5 via the air discharge path 7 by means of a manifold 19B folded as an elbow.
A second diffusing or diverging duct 22 is partially inserted in the duct 19. Both ducts 19 and 22 have a smaller air inlet portion and a diverging air outlet portion.
In a preferred embodiment, as shown in Fig. 1, the duct 22 is disposed coaxially in the duct 19. In particular, the duct 22 is inserted with its smaller inlet portion through a section Δ within the duct 19 and has a free-portion 22A external to the duct 19. This free portion 22A projects from the duct 19 over a section having a linear dimension smaller than the overall length of the duct 22.
Both the outlet section of the diverging portion of the duct 19 and the diverging outlet section of the duct 22 are therefore in fluid communication with the container 3A.
The ducts 19 and 22 are substantially perpendicular to the free surface L of the fluid 17, so as to cause the air discharged from the motor/suction unit 5 to impact the surface of this fluid.
Advantageously, the particular diverging configuration of the duct 19 means that the air is subject to a first reduction of its speed, and a subsequent speed reduction is obtained at the outlet section of the second duct 22. In practice, a minority portion of the flow of air flowing in the duct 19 flows out laterally to the duct 22 (arrows H) while the remaining portion, i.e. a majority portion of the flow of air flowing in the duct 19, enters the smaller inlet section of the duct 22 (arrow I).
In a further embodiment (not shown), the duct 19 may have the inlet section of the smaller portion in fluid communication with the motor/suction unit 5 and the outlet section of the diverging portion in fluid communication with the smaller inlet portion of the duct 22. The latter has, in turn, its own diverging air outlet portion in fluid communication with the container 3A. In other words, the ducts 19 and 22 are mutually connected one after the other.
The air discharge path 7 comprises valve means 20 adapted to allow the one-way passage of the air discharged by the motor/suction unit 5, as shown in detail in Fig. 5.
Advantageously, the valve means 20 are disposed within the manifold 19B and take the form in practice of a closure flap hinged by a hinge 21 on the duct 19 upstream of the manifold 19B.
The function of these valve means is to enable and/or prevent-the fluid communication between the motor/suction unit 5 and the container 3A depending on the pressure conditions within this duct 19.
In particular, the closure flap is adapted to assume a first operating configuration (open position shown in Fig. 5) in the presence of the flow of air discharged from the motor/suction unit 5 and a second operating configuration (closed position) in the absence of this flow or in the event of inexpert manoeuvres by the user. In practice, following inexpert movements of the vacuum cleaner 1, for instance upturning of the vacuum cleaner, it is necessary to prevent the fluid 17 in the container 3A from flowing along the duct 19 to the motor/suction unit 5 with the obvious and imaginable consequences. In this case, the closure flap would pass, under the thrust of the fluid 17, from the first operating position (open position) to the second operating position (closed position) closing off the outlet opening 16 of the body 2.
The closure flap may also intervene on those occasions when the user has inserted an excessive amount of fluid 17 into the container 3A.
Alternatively, the valve means take the form in practice of a system of pneumatic type provided with instantly expanding hydro-sensitive means whose purpose is instantly to close the air discharge path 7 so as to guarantee the safety of the user and to safeguard the motor/suction unit 5 against an inevitable short-circuit.
A person skilled in the art could obviously substitute other valve means structurally and/or operationally equivalent to those described for the valve means 20.
A filter-holder 24, through which the duct 19 extends from end to end, is inserted in the container 3A in the vicinity of an outlet slot 23.
A filter 25 and a stop device 26 are disposed within the filter-holder 24.
The filter 25 is adapted to retain any solid impurities conveyed in the air mixed with fluid (arrows N) such as hairs, threads, etc. It is formed from an impermeable material, which may be metal, provided with holes having a diameter which is not too small. The fact that the holes of the filter 25 have a diameter which is not too small means that any load losses due to this filter are particularly limited.
Advantageously, this filter 25 may be readily removed from the filter-holder 24 so that any impurities may be cleaned from it by washing.
The stop device 26 is adapted to stop the supply of the motor/suction unit 5 when conditions which may compromise the safety of the user occur.
A sensor 27 of the fluid level is provided in the tank 3 and may be connected to the stop device 26 so as to stop the operation of the motor/suction unit 5 when the level L of the fluid 17 in the container 3A exceeds or drops below a predetermined threshold.
If, therefore, the level L reached by the fluid 17 in the container 3A becomes excessive or drops below a predetermined minimum threshold indispensable for the correct operation of the vacuum cleaner 1, the operation of the motor/suction unit 5 is stopped to enable the user to empty or fill the tank 3 as necessary.
The signal generated by the sensor to indicate an excess or shortage of fluid in the container 3A may also drive appropriate visual and/or acoustic warning means (not shown), for instance warning lights of the state of the vacuum cleaner 1, to enable the user quickly to pinpoint what has caused the vacuum cleaner to stop operating.
Lastly, when the fluid 17 in the container 3A exceeds a predetermined level and the motor/suction unit 5 stops as a result of the signal supplied by the sensor 27, the user may simply extract the container 3A, empty it and insert it again in order to continue to use the vacuum cleaner 1.
In the embodiment shown in Fig. 6, the level sensor 27 takes the form of a sensor able to monitor the level L of the fluid 17 in the container 3A and to detect the degree of turbidity of this fluid, in accordance with techniques well known to a person skilled in the art.
With further reference to Fig. 1, it can be seen that a float 28 guided by guide means 29 is disposed in the container 3A.
The float 28 is substantially constrained to remain in the vicinity of the diverging outlet of the duct 22A by guide means 29. In particular, the guide means 29 take the form of a plurality of walls or rods disposed to form a cage which extend vertically from the base of the container 3A at the location of the diverging outlet of the duct 22.
The float 28 takes the form, for instance, of a sphere formed from plastics material or from a material having like properties. In particular, this float 28 has a diameter such that it is able to close off the duct 22.
This is useful when the user carries out inexpert manoeuvres with the vacuum cleaner 1. When the vacuum cleaner 1 is upturned, for instance, especially when the motor/suction unit 5 is still being supplied, the float 28 is guided by the guide means 29 to enter the diverging outlet section of the duct 22 in order to close it off completely. In practice, once the float 28 has entered the duct 22, it slides until reaching a stop position as a result of which the duct 22 is closed off. The only escape route that the fluid 17 has is the space between the duct 19 and the duct 22 but, once the fluid 17 comes into the vicinity of the opening 16 of the body 2, the fluid itself exerts a pressure on the valve means 20 which move from the open to the closed position, thus preventing the fluid from reaching the motor/suction unit 5. In this way, the safety of the user is guaranteed and the motor/suction unit 5 is protected from an inevitable short-circuit.
It should be noted that to facilitate the necessary operation of filling and/or topping up of the container 3A, a graduated window 30 is provided so as immediately to quantify the level reached by the fluid within the container 3A.
In operation, the user fills the container 3A with fluid 17 up to a desired level which can be checked by means of the appropriate graduated window 30. The container 3A is in turn inserted in the tank 3 and if the sensor 27 so allows, it is possible to start the motor/suction unit 5. This unit 5 suctions air towards the container 4 via the inlet aperture 8. The suctioned flow of air containing dust and/or solid particles passes firstly into the axial cyclone 11 where a first purification stage takes place and then flows through the star-shaped filter 6A where it is subject to a second filtration action, and is then deflected by the deflector 13 and lastly flows through the duct 19 (arrow G) into the container 3A.
As described above, the particular diverging configuration of the duct 19 means that the air is subject to a first reduction of its speed and a subsequent speed reduction is obtained at the outlet section of the possible second duct 22.
The flow of air emerging from the diverging portion of the ducts 19 and 22 (arrows M) impacts, at a speed which is lower than its speed on output from the motor/suction unit 5, against the free surface of the fluid 17, promoting the creation of swirling and turbulent movements of moderate extent but able to give rise to the coalescence of the particles of dust and dirt contained in the flow of air and the fluid which is itself partially atomised.
This brings about, in the container 3A, a fluid saturated environment which facilitates the mixing of the solid particles in the suctioned dust-containing flow with the particles of fluid in suspension in the tank 3.
This therefore provides a filtration of the solid particles using a post-motor filtering design, i.e. the extraction of the dust residues takes place by means of the fluid 17 disposed upstream of the motor/suction unit 5.
It will be appreciated that these solid particles are the particles that have passed unchanged through the star-shaped filter 6A or which have not been trapped therein.
In vacuum cleaners of the prior art, use is normally made of costly filters of the type commonly known as "HEPA" filters in order to filter these residues. These filters are disposed at the outlet of the vacuum cleaner.
Advantageously, the vacuum cleaner 1, in accordance with the present invention, does not require such "HEPA" filters as the residual solid particles discharged by the motor/suction unit 5 are retained by the fluid 17.
After mixing with this fluid 17, the residual particles tend to fall, under the effect of gravity, towards the base of the container 3A into this fluid, while the particles of mass smaller than the former mixed with water are conveyed (arrows N) with the flow of air towards the outlet 23 (arrows P) of the tank 3.
This ensures the discharge of slightly humid air into the environment surrounding the vacuum cleaner 1, this discharged air being more tolerable than a flow of dry air as generated by known vacuum cleaners.
The vacuum cleaner of the present invention is therefore particularly efficient since it does not require the use of filters with pores of an extremely small diameter entailing substantial losses of load in the suction circuit and thereby reducing the suction vacuum in the take-up section of the external duct.
A person skilled in the art could obviously, in order to satisfy contingent and specific requirements, make any modifications and variations to the embodiments described above, without thereby departing from the scope of protection of the invention as set out in the following claims.

Claims

A vacuum cleaner for domestic cleaning of the type comprising:
- a body (2) adapted to comprise suction means (5) in fluid communication with an air intake opening (8);

- filtering means (6A, 11) to filter the particles contained in the suctioned air, these filtering means (6A, 11) being interposed between the intake (8) and the suction means (5);

- an air discharge path for conveying a flow of air suctioned by the suction means (5) to an outlet opening (23);

- a tank (3, 3A) for a fluid (17) associated with the body (2) in order to be interposed in fluid communication between the suction means and the outlet (23);
whereby the flow of air suctioned by the suction means (5) is taken into the tank (3, 3A) in order to impact the free surface (L) of the fluid (17) in the tank (3, 3A) characterised in that the tank comprises means (19, 22) for reducing the speed of the flow of air suctioned by the suction means (5) before this flow impacts on the free surface (L) of the fluid (17) so as to generate, in this tank (3, 3A), a saturated environment of fluid in suspension above the free surface (L) of the fluid (17).
A vacuum cleaner for domestic cleaning as claimed in claim 1, characterised in that the means (19, 22) for reducing the speed of the flow of air discharged by the suction means (5) comprise at least a first duct (19) diverging in the direction of travel of the flow of air, this first diverging duct (19) being disposed above the free surface (L) of the fluid (17) in the tank (3, 3A).
A vacuum cleaner for domestic cleaning as claimed in claim 2, characterised in that the means (19, 22) for reducing the speed of the flow of air discharged by the suction means (5) comprise a second duct (22) diverging in the direction of travel of the flow of air in fluid communication with the first duct (19), this second duct (22) being immediately downstream of the first duct (19).
A vacuum cleaner for domestic cleaning as claimed in claim 3, characterised in that the second duct (22) is inserted over at least a section (Δ) within the first duct (19).
A vacuum cleaner for domestic cleaning as claimed in claim 4, characterised in that the second duct (22) is inserted coaxially within the first duct (19).
A vacuum cleaner for domestic cleaning as claimed in claim 4 or 5, characterised in that the second duct (22) has a portion (22A) projecting from the first duct (19), this projecting portion (22A) having a linear dimension smaller than the section (Δ).
A vacuum cleaner for domestic cleaning as claimed in any one of the preceding claims, characterised in that the tank (3, 3A) comprises a container (3A) that may be removed from the tank (3) by extraction.
A vacuum cleaner for domestic cleaning as claimed in claim 7, characterised in that the tank (3A) comprises means (27) for detecting the level of the free surface (L) of the fluid (17) in the tank (3A), which means (27) may be connected to a stop device (26) for the de-activation of the suction means (5).
A vacuum cleaner for domestic cleaning as claimed in any one of the preceding claims, characterised in that the filter means (6A, 11) for filtering the particles comprise a star-shaped filter member (6A) and-an axial cyclone (11).
A vacuum cleaner for domestic cleaning as claimed in any one of the preceding claims, characterised in that it comprises valve means (20) for shutting off the fluid (17), these valve means (20) being disposed in the air discharge path (7).
A vacuum cleaner for domestic cleaning as claimed in claim 10, characterised in that the valve means (20) are positioned upstream of the first duct (19) and comprise a closure flap which may move between a first and a second operating position in which it enables, and respectively prevents, fluid communication.
A vacuum cleaner for domestic cleaning as claimed in claim 8 and 11, characterised in that the stop device (26) is adapted to cut off the supply to the suction means as a function of the first and second operating position of the valve means (20).
A vacuum cleaner for domestic cleaning as claimed in claim 2, characterised in that the first duct (19) has its diverging outlet section substantially perpendicular to the free surface (L) of the fluid (17).
A vacuum cleaner for domestic cleaning as claimed in claim 3, characterised in that the second duct (22) has its diverging outlet section substantially perpendicular to the free surface (L) of the fluid (17).
A vacuum cleaner for domestic cleaning as claimed in any one of the preceding claims, characterised in that the tank (3, 3A) comprises an impermeable filter member (25) in the vicinity of the outlet opening (23).