Patent Publication Number: US-6338750-B1

Title: Cleaning apparatus

Description:
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The present invention relates to a cleaning apparatus of the type comprising at least one suction device of a fluid, connected to a suction duct, and means for holding back any solid particles present in the sucked fluid. 
     Domestic cleaning apparatus providing for suction of an air-flow containing solid particles, also known by the name “vacuum cleaner”, usually comprises a suction pump connected to an external duct and means for separating and holding back the solid particles contained in the flow of sucked air. The suction pump creates an area of low air pressure in correspondence to the collecting section of the external duct, able to cause an air-flow containing any dust-or solid particles, directed toward the inside of the apparatus. Subsequently, the dust contained in the flow of sucked air is separated, for instance by means of a membrane filter, to allow clean air to be vented from the apparatus. 
     Therefore, in use, the operator directs the collecting section of the external duct, generally equipped with a shaped extremity, to above a specific surface of the object that needs cleaning and, operating, the pump, aspirates any solid particles present on the same surface into the cleaning apparatus. The airflow and sucked dust are induced to flow through a membrane filter, usually pouch-shaped, capable of holding back even very small solid particles. The membrane filter, however, placed between the collecting section and the suction pump, causes a notable loss of pressure in the suction circuit, and accordingly reduces the ability of the same apparatus to aspirate dust, because of the very small pore-dimension in the filtering membrane. 
     Furthermore, such membrane filter must be replaced regularly, because of the dust which accumulates during use and tends to offer increasing resistance to the flow of the air, involving the generation of a lower vacuum in correspondence to the collecting section of the suction duct and therefore degrading the performance of the cleaning apparatus. The operation of removal and substitution of the filter, which generally involves opening the body of the cleaning apparatus, separating the filter from the housing in which it is lodged, recovering the filter from the suction ducts and discharging it, assembling the new filter and closing the body, is not easy and requires the elimination, and consequent replacement of consumable materials. 
     Finally, whenever a liquid is erroneously sucked by the above described apparatus, the membrane filter (usually of paper material) could soften and tear because of the absorption of the same liquid. Such laceration would allow solid particles to flow into the suction circuit and to penetrate the suction pump, jeopardising the operation of the cleaning apparatus. Therefore, suction of liquids must be avoided by such apparatus. 
     On the other hand, cleaning apparatuses are known that, equipped with a steam generator and with means for the delivery of the steam, also comprise devices for the suction of liquids. 
     In such apparatuses, which allow the washing of the surfaces that are to be cleaned, a jet of steam under pressure is delivered that loosens any encrusted dirt and favours the mixing of the particles of dust with the water resulting from the condensation of the same steam. This mixture of water and dust is sucked simultaneously with the delivery of the steam by the cleaning apparatus and, for instance, made to fall by gravity—exploiting the weight of the mixture—into a collection container. In these embodiments, the sucked wet dust accumulates in the collection container and must be emptied regularly by the operator. 
     But, the cleaning apparatuses equipped with a steam generator and with means for the suction of liquids are not able to aspirate dry dust, or dust not mixed with water, because they don&#39;t comprise means for separating the dust from the air-flow, such as for instance a membrane filter. In similar apparatuses, to avoid dust not mixed with water damaging the same suction device, the operation of suction is activated only simultaneously with the delivery of the steam. 
     OBJECTS OF THE INVENTION 
     One purpose of the present invention is to provide a cleaning apparatus that is able to aspirate both dry solid particles and liquids present on a surface and to separate the solid particles and the liquid from the flow of discharged air. 
     A further purpose of the present invention is to provide a cleaning apparatus that is particularly versatile and easy to use. 
     Another purpose of the present invention is to get a cleaning apparatus that allows only the suction of dust from dry surfaces or, alternatively, the delivery of steam and the subsequent suction of dust mixed with water. 
     SUMMARY OF THE INVENTION 
     These and other purposes are achieved by the cleaning apparatus according to the principal claim and the following dependent claims. 
     A cleaning apparatus according to the present invention comprises a suction device of a fluid toward the inside of the apparatus connected to an external suction duct, and means of holding back the solid particles, located between the suction device and the external duct. Such means for holding back the solid particles comprises a mixing chamber partially filled with a liquid and means for causing turbulence in the mixing chamber, in such a way as to create in the latter a saturated environment of liquid in suspension above the free surface of the same liquid. 
     In a preferred form of embodiment, the cleaning apparatus comprises further means for the reduction of the speed of the sucked fluid interposed between the means for causing the turbulence and the suction device. 
     According to a particular aspect of the invention, the means for causing turbulence and the means for the reduction of the speed of the sucked fluid comprise a first Venturi tube in fluid communication with the mixing chamber and with a further collection chamber. The Venturi tube is arranged above the free surface of the liquid contained in the mixing chamber. 
     In a further embodiment of the cleaning apparatus according to the present invention, the said mixing chamber and the collection chamber are in fluid communication with each other, either below or corresponding to the free surface of the liquid initially contained in the mixing chamber. 
     According to a preferential embodiment of the invention, the means for causing the turbulence comprises a further Venturi tube placed downstream of the first Venturi tube. Furthermore, membrane filtering means are present at least partially located in the first Venturi tube. 
     In another particular form of embodiment, the Venturi tube is of the divergent type and presents the reduced portion entry section in fluid communication with the mixing chamber, and the divergent portion exit section in fluid communication with the collection chamber. 
     According to another aspect of the invention, the collection chamber presents a discharging duct connected to the suction device and a sensor of the level of liquid present in the collection chamber; the sensor is connected to means for interrupting the operation of the suction device in the event of the level of the liquid in the mixing chamber reaching or exceeding a pre-set threshold. In a further form of embodiment, the cleaning apparatus according to the invention comprises a reservoir for the water, as well as means for generating and delivering steam and/or water at high temperature connected to this reservoir. 
     Some preferential embodiments of the cleaning apparatus according to the present invention will now be described by way of example and not of limitation, with reference to the attached drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a scheme of a cleaning apparatus according to a particular aspect of the present invention, comprising means for the generation and delivery of steam; 
     FIG. 2 is a side view in section of the mixing and collection chambers of a cleaning apparatus according to the invention; 
     FIG. 3 is a top view in section of the mixing and collection chambers of FIG. 2; 
     FIG. 4 is a schematic profile view, in section, of a particular cleaning apparatus according to the invention; 
     FIG. 5 is a scheme of a further embodiment according to the invention; 
     FIG. 6 is a side view in section of a mixing chamber and of a collection chamber of a cleaning apparatus according to a different form of embodiment of the invention; and 
     FIG. 7 is a top view in section of the mixing chamber and of the collection chamber of FIG. 6; 
     FIG. 8 is a profile view in section of the vent duct of a cleaning apparatus, according to a particular aspect the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a scheme of d particular embodiment of the invention in which the cleaning apparatus comprises means for the generation and delivery of steam. 
     This cleaning apparatus comprises an external suction duct  1  connected to a suction device  3  that creates an area of low air pressure in correspondence of the collecting section of the same duct  1 . Between the duct  1  and the suction device  3  is interposed the means  2  for holding back the solid particles comprising a mixing chamber  4  in fluid connection with a further collection chamber  5 . The mixing chamber  4 , which is partially filled with a liquid  7 , is directly connected with the intake section  8  of the duct  1  and is in connection with the collection chamber  5  by means of a connecting section  30 , located under the free surface of the liquid present in the chambers  4  and  5 , and by means of two Venturi tubes  6  and  31 , set one upstream the other, above the free surface of the liquid  7 . 
     The collection chamber  5  presents a discharging duct  9 , connected to the suction device  3 , and a level sensor  10  of the liquid present in chamber  5  connected to means  12  for interrupting the operation of the suction device  3  whenever the level of the liquid inside chamber  5  reaches or exceeds a pre-set threshold. 
     The low air pressure created by the device  3  in correspondence of the collecting section of the duct  1  is able to cause a flow directed toward the intake section  8  of the same duct  1 , and therefore toward the mixing chamber  4 , of any fluid in the gaseous or liquid state. 
     The fluid sucked toward the inside of the cleaning apparatus, containing dust or solid particles, goes on to the inside of chamber  4 , where the dust mixes with the liquid present in the same chamber  4 ; this is followed by the precipitation of the heavier particles of dust mixed with the liquid. The lighter particles of dust mixed with the liquid are, instead, drawn by the airflow through the two Venturi tubes  6 ,  31  and arrive in the collection chamber  5 , where, as a result of the reduction of speed in the flow of fluid that transports them due to the Venturi tubes  6 ,  31 , they fall down. The sucked air in chamber  5  finally transits into the discharging duct  9  and is expelled from it via the vent  11 , placed downstream of the suction device  3 . The cleaning apparatus illustrated in the scheme of FIG. 1, furthermore comprises a reservoir  20  for the water in the liquid state that feeds, via a pump  19 , a boiler  16  for the generation of steam. The boiler  16 , where pre-set conditions of temperature and pressure are maintained, presents a manifold for collecting the steam  15 . Downstream of the manifold  15 , in fluid connection with it, are set two operator-controlled solenoid valves  14   a  and  14   b  to regulate the flow of steam to a delivery nozzle  13 . The apparatus furthermore comprises a control unit  18 , connected to a sensor  17  present in the boiler  16 , that regulates the level of the liquid and the thermodynamic conditions in the same boiler  16 . 
     This control unit  18  is also able to detect and control the level of the liquid in the reservoir  20 , to prevent the operation of the cleaning apparatus in the case where there is not sufficient liquid available for its correct operation. 
     FIGS. 2 and 3 show two views in section of the mixing and collection chambers,  4  and  5  respectively, of a further form of embodiment of the apparatus according to the present invention. In particular, chambers  4  and  5  are connected, above the free surface of the liquid  7 , by means of two Venturi tubes  6  and  31  in series, and below the free surface of the liquid  7 , by means of a passage  30 . The passage  30 , may be fitted with one-way valve means  42 , allowing the flow of liquid only from chamber  5  to chamber  4  when the suction device is not in operation. 
     The collection chamber  5  is equipped with a baffle  33 , fixed in proximity to the upper extremity of the same chamber  5 , a discharging duct  9  connected to the suction device, as well as a level sensor  10  for the liquid, located in correspondence to the lower portion of the chamber  5 . 
     The baffle  33  comprises a horizontal portion, extending from the vertical wall of the chamber  5  to the front of the Venturi tube  31 , and an oblique portion that is partially superimposed on the exit section of the same Venturi tube  31  and is tilted toward the lower extremity of the same chamber  5 . This baffle  33  has the function of breaking the flow of fluid, particularly air, coming out from the Venturi tube  31  and of preventing dust carried by the sucked fluid from directly reaching the discharging duct  9 . 
     The level sensor  10 , whenever the level of the liquid  7  in the two chambers  4  and  5  climbs above, or falls below a pre-set threshold, generates a signal that is transmitted to suitable means of control (not shown) and causes the interruption of the operation of the suction device. Therefore, if the level reached by the liquid in the chambers  4  and  5  exceeds or is under a threshold that is essential for the correct operation of the apparatus, the operation of the suction device is interrupted to allow the operator to either empty or fill the two chambers. 
     The signals generated by the sensor  10 , respectively to indicate the excess or the lack of liquid in the chambers  4  and  5 , can also pilot suitable means of signalling the “apparatus status”, for instance bright warning lights, (not shown) to allow the operator to quickly identify the cause of the interruption of the operation of the apparatus. 
     Corresponding to the ceiling of chamber  4 , above the Venturi tube  6 , there is furthermore present the intake section  8  of the external collecting duct of the apparatus. The discharging duct  9  and the intake section  8  of the suction duct present two elbow portion, indicated by  34  and  35  respectively, which, although involving light losses of pressure, allow the external dimensions of the cleaning apparatus to be contained. 
     The Venturi tube  6  and the Venturi tube  31 , reciprocally connected one within the other, are of the divergent type, both present a reduced entry portion of the fluid and a divergent exit portion of the same fluid. The Venturi tube  6 , particularly, presents the reduced portion entry section in fluid communication with the mixing chamber  4  and the divergent portion exit section in fluid communication with the reduced entry portion of the Venturi tube  31 . The Venturi tube  31  presents, in turn, its own divergent exit portion in fluid communication with the collection chamber  5 . In proximity to the entry section of the Venturi tube  6  is furthermore located, partially superimposed on the latter, a cup  26  that defines a nonlinear course for the flow of fluid directed toward the Venturi tube  31  and, accordingly, toward the collection chamber  5 . 
     According to a particular aspect of the invention, furthermore, a cylindrical membrane filter  32  can also be present, located partially inside the Venturi tube  6 . The filter  32  comprises an impermeable material, even metal, and is endowed with pores not having an excessively reduced diameter, since they must hold back solid particles of not elevated mass mixed with portions of liquid present in the chambers  4  and  5 . The not excessively reduced diameter of the pores of the membrane makes the losses of pressure, due to the same membrane, particularly contained. Advantageously, such filter  32  is removable from the seat indicated and could easily be cleaned of any impurities, by means of washing. 
     The low air pressure created by the suction device in the collecting duct, causes a flow of fluid directed toward the same suction device which, coming out of the intake section  8  of the collecting duct, is introduced into the chamber  4  partially filled with a liquid  7 . The presence in the chamber  4  of the Venturi tube  6 , which causes a further air pressure fall corresponding to its own entry section, favours the creation of vortexes and turbulent motions that involve both the gaseous phase and the liquid phase present in the same chamber  4 . Consequently, inside chamber  4  there is created a saturated environment of liquid in which turbulence in the fluids present is propagated. 
     The environment thus produced facilitates the mixing of the solid particles present in the sucked fluid with the particles of liquid present in suspension in chamber  4  and the separation of this mixture from the same sucked fluid. After the mixing, the particles of higher mass tend to fall, by gravity, toward the bottom of the chamber  4  into the liquid  7 , while the particles of lower mass are drawn, with the flow of sucked fluid, into the Venturi tube  6  and from there into the Venturi tube  31  to be introduced into the collection chamber  5 . 
     The flow of sucked fluid, containing dust particles of reduced mass, undergoes a first reduction of speed corresponding to the exit section of the first Venturi tube  6  and a further reduction of speed corresponding to the exit section of the second Venturi tube  31 . Because of this reduction in speed of the sucked fluid, which is caused in the collection chamber  5  due to the divergent Venturi tubes  6  and  31 , the particles of inferior mass are no longer supported by the sucked fluid and fall by gravity to the bottom of the same chamber  5 . 
     Finally, when the liquid  7  present in the collection chamber  5 , and in the mixing chamber  4 , exceeds a pre-set level, and provokes the trip-out of the suction device by the sensor  10 , the operator can simply extract the chambers  4  and  5  together, empty them and reinsert them to continue using the apparatus. FIG. 4 illustrates, schematically, a particular form of embodiment of a domestic cleaning apparatus according to the present invention. This apparatus comprises a body  29 , mounted on wheels to give mobility, having a suction duct.  1 , an electrically-driven suction device  3 , as well as a mixing chamber  4  connected by means of two Venturi tubes  6  and  31  in series to a collection chamber  5 . The two chambers  4  and.  5  are further connected by a connecting passage  30  located below the level of the free surface of the liquid. In the fig. a duct  43  for the partial filling of the chamber  4  with a liquid and a vent  11  for the sucked fluid are shown. 
     The presence of the liquid  7  (water, for instance) in the mixing chamber  4 , with the function of mixing the dust present in the sucked fluid, thus allows the apparatus to suck both dry dusts and the wet dust and liquids. So, the operator can, by partially filling the mixing chamber with a suitable quantity of water, clean dry surfaces, or wet surfaces, or aspirate liquid from a container, using the same cleaning apparatus. 
     Furthermore, in particular forms of embodiment of the present invention equipped with means for the generation and delivery of steam and/or water at high temperatures, the operator could employ this apparatus equally either as a traditional vacuum cleaner or as a steam-cleaning apparatus. 
     FIG. 5 shows a scheme of a cleaning apparatus according to another aspect of the present invention. 
     This apparatus comprises a suction duct  1 ′ having an intake section  8 ′ connected to a mixing chamber  4 ′. The mixing chamber  4 ′, partially filled by a liquid  7 ′, for instance water, is in turn connected, by means of a single Venturi tube  6 ′ to a collection chamber  5 ′. The collection chamber  5 ′ is in fluid communication with a discharging duct  9 ′, connected in turn to a suction device  3 ′ and to a vent  11 ′. The employment of a single Venturi tube  6 ′ makes, for parity of dimension, the operation of separation of the dust from the sucked s fluid less effective, but the apparatus is simpler to construct. 
     The mixing chamber  4 ′ and the collection chamber  5 ′, furthermore, are no longer connected below the free surface of the liquid and therefore, the level of the free surface itself of the liquid in the two chambers  4 ′ and  5 ′ is different. This situation, while not influencing the operation of the apparatus, involves the need to employ two different level sensors  21  and  10 ′ for the liquid in the two chambers  4 ′ and  5 ′ and for more rapid filling of the mixing chamber  4 ′. 
     The apparatus comprises a reservoir for the water  24  connected to a pump  23  for the filling of the mixing chamber  4 . The pump  23  is operated by a control unit  22  connected to a sensor  21  for the detection of the level of the liquid present in the chamber  4 ′. When the level of the free surface of the liquid in the chamber  4 ′ is below a pre-set threshold, the control unit  22  operates the pump  23  that feeds the chamber  4 ′ from the liquid present in the reservoir  24  until the optimal level of the liquid inside the same chamber  4 ′ is restored. The employment of the control unit  22 , in partnership with the pump  23  and the reservoir  24 , prevents incorrect use of the cleaning apparatus whenever there is not sufficient liquid in the chamber  4 ′. 
     The collection chamber  5 ′ is, in turn, equipped with a sensor  10 ′ to survey the level of the free surface of the liquid present in the same chamber  5 ′ connected to means for the interruption of the operation of the suction device  3 ′. When the level of the free surface of the liquid present in the collection chamber  5 ′ exceeds a determined level, the sensor  10 ′ generates a signal that, due to the above-mentioned means of interruption, causes the operation of the suction device  3 ′ to be interrupted. 
     The apparatus represented in the scheme of FIG. 5 can furthermore be advantageously joined to means for the generation and delivery of steam and/ or water at high temperature, sharing with these latter the use of only one reservoir for the feeding of water to the boiler  16  (FIG. 1) and to the mixing chamber  4  or  4 ′. FIGS. 6 and 7 show views in section from the side and from the top respectively, of a particular embodiment of the mixing and of collection chambers connected by means for causing turbulence according to another aspect of the invention. 
     In particular, the mixing chamber  4 ′ and the collection chamber  5 ′ are in fluid communication, due to the passage  30 ′, either in correspondence with their lower extremity, or below the free surface of the liquid  7 ′ initially contained in the mixing chamber  4 ′. The mixing chamber  4 ′ in proximity of whose ceiling is present the intake section  8 ′ of a duct of external suction, is in fluid communication with the collection chamber  5 ′ by means of a Venturi tube  6 ′ located above the free surface of the liquid  7 ′ present in the chambers  4 ′ and  5 ′. 
     The collection chamber  5 ′ is, in turn, in fluid connection with the discharging duct  9 ′ that could carry a filtering element (not shown), placed upstream of the same suction device. 
     Furthermore, the collection chamber  5 ′ presents a baffle  33 ,′ extending for all the width of the same chamber  5 ′, located in front of the divergent exit section of the Venturi tube  6 . The baffle  33 ,′ thus located, has the function of breaking the flow of fluid, particularly of air, coming out from the same Venturi tube  6 ′ and preventing the dust drawn from the fluid directly reaching the discharging duct  9 ′. 
     To prevent the free surface of the liquid in the chambers  4 ′ and  5 ′ exceeding such a level as to jeopardise the operation of the cleaning apparatus, the employment of a level sensor  10 ′ of the liquid in the chamber  5 ′ is proposed. Whenever the liquid in the chambers  4 ′ and  5 ′ goes beyond a pre-set level, the means (not shown) for interrupting the operation of the suction device of the fluid come into operation. The sensor  10 ′ can also operate such means for interrupting the operation of the suction device whenever the free surface of the liquid in the chambers  4 ′ and  5 ′ reach or exceed a pre-set level. 
     FIG. 8, finally, shows the terminal section of a vent duct  37  of the sucked fluid, placed downstream of the suction device and partially projecting from the body  40  of the cleaning apparatus. In particular, the terminal section of the vent duct  37  is of circular form and presents a grate  38 , for venting the air toward the external environment, that is equipped with slits  39  tilted upwards, to prevent the jet of venting air going toward zones not yet cleaned and disturbing and raising the dust present there. 
     The vent duct  37  could be endowed with a filtering element  41  placed downstream of the suction device. Corresponding to this filtering element  41  could be placed, in a suitable container permeable to the air, a perfuming substance for the air-flow in exit. The cleaning apparatus according to the present invention is particularly effective and versatile, because it can be used indiscriminately for the cleaning of dry surfaces or of wet surfaces and could be fitted easily with means for the generation and delivery of steam and/or water at high temperatures. 
     The cleaning apparatus according to the present invention, is particularly efficient and doesn&#39;t require the employment of filters with extremely reduced pore diameter that involve considerable loss of pressure in the suction circuit, with consequent reduction in the air pressure of suction in the collecting section of the external duct. 
     Furthermore, this apparatus is easy and economical to use, since it does not need complicated operations for the elimination of the accumulated dust and doesn&#39;t require regular replacement of spare-parts.