Patent Publication Number: US-9903065-B2

Title: Laundry washing machine

Description:
Aspects of the present invention concerns the field of laundry washing techniques. 
     In particular, aspects of the present invention refers to a laundry washing machine capable of performing a more efficient washing cycle. 
     BACKGROUND 
     Nowadays the use of laundry washing machines, both “simple” laundry washing machines (i.e. laundry washing machines which can only wash and rinse laundry) and laundry washing-drying machines (i.e. laundry washing machines which can also dry laundry), is widespread. 
     In the present description the term “laundry washing machine” will refer to both simple laundry washing machines and laundry washing-drying machines. 
     Laundry washing machines generally comprise an external casing provided with a washing tub which contains a rotatable perforated drum where the laundry is placed. 
     A loading/unloading door ensures access to the drum. 
     Laundry washing machines typically comprise a water inlet circuit and a products supply unit for the introduction of water and washing/rinsing products (i.e. detergent, softener, etc.) into the tub. 
     Known laundry washing machines are also provided with water draining devices that may operate both during the initial phases of the washing cycle and at the end of the same to drain the dirty water. 
     According to the known technique, a complete washing cycle typically includes different phases during which the laundry to be washed is subjected to adequate treatments. 
     A washing cycle usually comprises a laundry wetting phase with addition of a washing detergent and a main washing phase during which the drum is rotated and the water contained therein is heated to a predetermined temperature based on the washing program selected by the user. During the main washing phase the drum is rotated, so as to apply also a mechanical cleaning action on the laundry. At the end of the main washing phase the drum is typically rotated at high rotational speed, in such a way that dirty washing liquid (i.e. water mixed with detergent and dirty particles) is extracted from the laundry, and this dirty washing liquid is drained by the water draining devices. 
     A successive step of the cycle typically comprises a rinsing phase which usually comprises one or more rinsing cycles. In the rinsing cycle, clean rinse water is first added to the laundry, so as to be absorbed by the laundry and remove from the latter detergent and/or dirty particles not previously removed by washing liquid, and then the drum is rotated to extract water and dirty particles/detergent from the laundry: the dirty water extracted is drained from the tub to the outside by the water draining devices. 
     After the rinsing phase, a final spinning phase allows the extraction of the residual water contained in the wet laundry. 
     The water extracted during the spinning phase is drained towards the outside by means of the water draining devices (during or after the spinning phase). 
     A laundry washing machine performing a washing cycle is disclosed in document CN101696544A. 
     Such laundry washing machine comprises a tub having a cylindrical structure for containing washing water and a rotary drum rotatably installed in the tub. 
     The machine further comprises a recirculating circuit having one recirculating pump which withdraws liquid from the bottom of the tub and re-admits such liquid at the bottom of the tub or into an upper portion of the tub. 
     Therefore, a first liquid circuit recirculates liquid at the bottom of the tub and a second liquid circuit recirculates liquid at the upper portion of the tub. 
     At this purpose, the recirculating pump outlet is connected to a three-way valve, with one inlet and two outlets, which selectively diverts liquid from the bottom of the tub again to the bottom of the tub or to the upper portion of the tub by means of respective pipes connected to the outlets. 
     The liquid is re-circulated at the bottom of the tub in the first liquid circuit when the dissolution of the detergent inside the tub is required. 
     The liquid is re-circulated in the second liquid circuit at the upper portion of the tub in order to increase the absorption of the liquid by the laundry inside the tub. 
     The choice between the first and the second liquid circuit is therefore carried out by properly controlling the three-way valve. 
     SUMMARY 
     It is an object of the invention to improve the washing efficiency of a laundry washing machine of the known type, as above described. 
     It is another object of the invention to provide a laundry washing machine that makes it possible to control efficiently the recirculation of liquid inside the tub. 
     The applicant has found that by providing a laundry washing machine comprising a washing tub external to a rotatable washing drum adapted to receive laundry, a first recirculation circuit suitable for withdrawing liquid from the washing tub and to re-admit such a liquid into a first region of the washing tub, a second recirculation circuit suitable for withdrawing liquid from the washing tub and to re-admit such a liquid into a second region of the washing tub, and by providing a first recirculation pump suitable for forcing liquid inside the first recirculation circuit and a second recirculation pump suitable for forcing liquid inside the second recirculation circuit, it is possible to obtain a laundry washing machine having an increased washing efficiency compared to the machines of known type. 
     Advantageously, it is possible to control independently the two recirculation circuits. 
     Aspects of the present invention relates, therefore, to a laundry washing machine comprising:
         a washing tub external to a rotatable washing drum adapted to receive laundry;   a water supply circuit to supply water into the washing tub;   a washing/rinsing products supplier to supply washing/rinsing products into the washing tub;   a liquid outlet circuit suitable for withdrawing liquid from the washing tub and to convey such a liquid to the outside;   a first recirculation circuit suitable for withdrawing liquid from said washing tub and to re-admit such a liquid into a first region of said washing tub, said first recirculation circuit comprising a first recirculation pump suitable for forcing liquid inside said first recirculation circuit;   a second recirculation circuit suitable for withdrawing liquid from said washing tub and to re-admit such a liquid into a second region of said washing tub;
 
the second recirculation circuit comprises a second recirculation pump suitable for forcing liquid inside the second recirculation circuit.
       

     Preferably, the machine further comprises a filtering device fluidly connected to an outlet of the washing tub, wherein the first recirculation pump is connected to a first outlet of the filtering device and the second recirculation pump is connected to a second outlet of the filtering device. 
     More preferably, the first outlet of the filtering device and the second outlet of the filtering device are arranged at opposite sides with respect a central plane intersecting the filtering device. 
     In a preferred embodiment of the invention, the liquid outlet circuit comprises a draining pump connected downstream of the filtering device. 
     In another preferred embodiment of the invention, the liquid outlet circuit comprises a draining pump, the draining pump being connected downstream of a second filtering device. 
     Preferably, the first region of the washing tub is a higher region with respect to the second region of the washing tub. In other words, the first region is placed, when the laundry machine is its operating position (i.e. installed for example on the floor of a building), at a height higher than the second region. 
     Preferably, the first recirculation circuit is arranged in such a way that the recirculated liquid is conveyed to the laundry, so as to wet the latter. 
     Advantageously, the second recirculation circuit re-admits the liquid into a lower region of the washing tub so as to improve the dissolution of the washing/rinsing product collected therein. 
     In a preferred embodiment of the invention, the second recirculation circuit re-admits the liquid into a lower seat of the washing tub which receives a heater device. 
     Opportunely, the first recirculation pump and the second recirculation pump are mounted on a support body obtained in a single piece construction. 
     Advantageously, the support body comprises a first inlet and a first outlet for the first recirculation pump and comprises a second inlet and a second outlet for the second recirculation pump. 
     In a preferred embodiment of the invention, the machine of the invention is a laundry washing-drying machine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further characteristics and advantages of the present invention will be highlighted in greater detail in the following detailed description of a preferred embodiment of the invention, provided with reference to the enclosed drawings. In said drawings: 
         FIG. 1  shows a perspective view of a laundry washing machine according to a preferred embodiment of the invention; 
         FIG. 2  shows the laundry washing machine of  FIG. 1  with the external casing removed and with some parts removed; 
         FIG. 3  shows the laundry washing machine of  FIG. 2  from another point of view; 
         FIG. 4  shows a partial view of the laundry washing machine of  FIG. 1  with the external casing partially removed and some parts removed; 
         FIG. 5  is a plan view of some components of the laundry washing machine of  FIG. 3  isolated from the rest; 
         FIG. 6  is a schematic view of a detail of the laundry washing machine of the invention; and 
         FIG. 7  shows an isometric view of a detail of the laundry washing machine illustrated in  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the present invention have proved to be particularly advantageous when applied to laundry washing machines, as described below. It should in any case be underlined that the present invention is not limited to laundry washing machines. On the contrary, the present invention can be conveniently applied to laundry washing-drying machines (i.e. laundry washing machines which can also dry laundry). 
     In the present description, therefore, the term “laundry washing machine” will refer to both simple laundry washing machines and laundry washing-drying machines. 
       FIG. 1  shows a laundry washing machine  1  according to a preferred embodiment of the invention. 
     The laundry washing machine  1  comprises an external casing or housing  2 , in which a washing tub  3  is provided that contains a rotatable perforated drum  4 , visible in the schematic view of  FIG. 6 , where the laundry to be treated can be loaded. 
     The tub  3  and the drum  4  both preferably have a substantially cylindrical shape. The housing  2  is provided with a loading/unloading door  8  which allows access to the washing drum  4 . 
     The tub  3  is preferably suspended in a floating manner inside the housing  2 , advantageously by means of a number of coil springs and shock-absorbers  9 . 
     The drum  4  is advantageously rotated by an electric motor, not illustrated, which preferably transmits the rotating motion to the shaft of the drum  4 , advantageously by means of a belt/pulley system. In a different embodiment of the invention, the motor can be directly associated with the shaft of the drum  4 . 
     The tub  3  is preferably connected to the casing  2  by means of an elastic bellows  7 , or gasket. 
     The tub  3  preferably comprises two complementary hemi-shells  13  and  14  structured for being reciprocally coupled to form the tub  3 . 
     The lower portion  3   a  of the tub  3 , or bottom of the tub, preferably comprises a seat  15  suitable for receiving a heater device  10 , as illustrated in  FIG. 4 . 
     The heater device  10  preferably comprises an electrical resistor of serpentine type. The heater device  10  is advantageously horizontally placed in the seat  15  and it preferably extends substantially from the front part up to the rear part of the seat  15 . 
     A water supply circuit  5  is arranged in the upper part of the laundry washing machine  1  and is suited to supply water into the tub  3 . The water supply circuit of a laundry washing machine is well known in the art, and therefore it will not be described in detail. 
     The laundry washing machine  1  advantageously comprises a removable drawer  6  provided with various compartments suited to be filled with washing and/or rinsing products (i.e. detergent, softener, etc.). 
     In a preferred embodiment, the water is supplied into the tub  3  from the water supply circuit  5  by making it flow through the drawer  6 . 
     The water which reaches the tub  3  can, in this case, selectively contain one of the products contained in the compartments of the drawer  6 , or such water can be clean and in this case it may reach the tub  3  directly, bypassing the compartments of the drawer  6 . 
     In an alternative embodiment of the invention, a further separate water supply pipe can be provided, which supplies exclusively clean water into the tub  3 . 
     Laundry washing machine  1  advantageously comprises a water outlet circuit  25  suitable for withdrawing liquid from the lower portion  3   a  of the tub  3 . 
     The water outlet circuit  25  preferably comprises a main pipe  17 , a draining pump  26  and an outlet pipe  28  ending outside the housing. 
     The water outlet circuit  25  preferably further comprise a filtering device  12  arranged between the main pipe  17  and the draining pump  26 . The filtering device  12  is adapted to retain all the undesirable bodies (for example buttons that have come off the laundry, coins erroneously introduced into the laundry washing machine, etc.) present inside the tub  3  during the draining of the washing/rinsing liquid through the water outlet circuit  25 . 
     This filtering device  12  can preferably be removed, and then cleaned, through a gate  40  placed advantageously on the front wall of the housing  2  of the laundry washing machine  1 . 
     The main pipe  17  connects the lower portion  3   a  of the tub  3  to the filtering device  12 . An inlet end  17   a  (see  FIG. 6 ) of the main pipe  17  is advantageously positioned at the lower point of the tub  3 , more preferably at the lower point of the seat  15  (if the seat  15  is provided). 
     An outlet end  17   b  (see  FIG. 6 ) of the main pipe  17  is connected to the filtering device  12 , preferably to a front part  12   a  of the filtering device  12 , as illustrated in  FIG. 5 . 
     In a further embodiment, not illustrated, the filtering device  12  may be provided directly in the tub  3 , preferably obtained in a single piece construction with the latter or more preferably with one of the shells composing the latter or partially with one shell and partially with another shell. In this case the filtering device  12  is fluidly connected to the outlet of the tub  3  in such a way that water and washing liquid drained from the tub  3  enters the filtering device  12 . 
     The draining pump  26  is preferably connected to a rear part  12   b  of the filtering device  12  and conveys the liquid to the outlet pipe  28  through an outlet  29 , the latest better visible in  FIG. 4 , in which the outlet pipe  28  has been removed for more clarity. 
     Activation of the drain pump  26  drains the liquid, i.e. water or water mixed with washing and/or rinsing products, from the tub  3  to the outside. 
     Laundry washing machine  1  advantageously comprises a first recirculation circuit  20  adapted to drain liquid from the lower portion  3   a  of the tub  3  and to re-admit such a liquid into a first region  3   b , advantageously an upper region, of the tub  3 . 
     Laundry washing machine  1  advantageously further comprises a second recirculation circuit  30  adapted to drain liquid from the lower portion  3   a  of the tub  3  and to re-admit such a liquid (recirculated mixing liquid) into a second region  3   c  of the tub  3 , which preferably corresponds substantially to the same lower portion  3   a  of the tub  3 . 
     The first recirculation circuit  20  preferably comprises a first recirculation pump  21 , a first pipe  22  connecting the filtering device  12  to the first recirculation pump  21  and a first recirculation pipe  23 , preferably provided with a terminal nozzle  23   a  arranged preferably at an upper region of the tub  3 . 
     The liquid from the lower portion  3   a  of the tub  3  is conveyed towards the upper region of the tub  3  by activation of the first recirculation pump  21 . 
     The first recirculation circuit  20  is advantageously activated in order to improve wetting of the laundry inside the drum  4 . 
     In general, the first recirculation circuit is properly realized for transferring a portion of a liquid from a region of the tub to another region of the tub in order to enhance absorption of washing liquid by the laundry. 
     In fact, during a washing cycle, one or more initial phases provides for the addition of a quantity of water and washing products inside the tub  3 . The water and the washing products are intended to wet the laundry inside the drum  4 . 
     The second recirculation circuit  30  preferably comprises a second recirculation pump  31 , a second pipe  32  connecting the filtering device  12  to the second recirculation pump  31  and a second recirculation pipe  33  advantageously provided with a terminal portion  34 , better visible in  FIG. 4 . The terminal portion  34  advantageously ends in the lower portion  3   a  of the tub  3 , preferably inside the seat  15 , if the latter is provided. 
     The liquid from the lower portion  3   a  of the tub  3  is conveyed again towards the lower portion  3   a  of the tub  3  by activation of the second recirculation pump  31 . 
     The second recirculation circuit  30  is advantageously activated when a further mixing and/or dissolution of the washing products is needed. 
     In general, the second recirculation circuit is properly realized for transferring a portion of a liquid from a bottom region of the tub to the same bottom region for mixing and/or dissolution of the washing products. 
     During a washing cycle, one or more phases provides for the addition of a quantity of washing products inside the tub  3 , for example a detergent in the initial phases of the washing cycle or a rinsing product in the final phases of the washing cycle. The washing products, or the rinsing products, which are introduced into the washing tub  3  due to their high density move towards the lower part  3   a  of the tub  3 . These products accumulate in the seat  15  which receives the heater device  10 . 
     To achieve the dissolution of the products which accumulate in said seat  15 , the terminal portion  34  of the second recirculation pipe  33  advantageously forces the recirculated mixing liquid along a main direction and collides with the product accumulated in the lower portion  3   a  of the tub  3  or seat  15 , if the latter is provided. 
     Advantageously, the terminal portion  34  of the second recirculation pipe  33  according to the invention avoids accumulation of products at the bottom of the tub  3  and enhances a complete and/or a fast dissolution of the products themselves in the water. 
     The washing performance of the washing cycle and the efficiency of the machine  1  are therefore increased. 
     Furthermore, all the products introduced by the user in the drawer  6  is used in the washing cycle without any losses. 
     Still advantageously, the second recirculation circuit  30  performs a cleaning effect since no products accumulate at the bottom of the tub  3 . 
     This guarantees good hygienic conditions inside the tub  3 , in particular when the laundry washing machine in not used for a long time between two successive washing cycles. 
     According to the invention, activation of the first recirculation circuit  20  and activation of the second recirculation circuit  30  may be advantageously carried out independently one to the other by means of activation of the respective first and second recirculation pumps  21 ,  31 . 
     During the washing cycle, therefore, and in particular during the initial phases of the washing cycle, the wetting of the laundry may be carried out independently from the dissolution of the product/products at the bottom  3   a  of the tub  3 . 
     The washing performance of the washing program and the efficiency of the machine  1  are therefore increased. 
     Another aspect of the invention is disclosed hereinafter with reference to  FIG. 6 , wherein only the first and the second recirculation circuits  20 ,  30  are schematically illustrated. The first and the second recirculation pumps  21 ,  31  communicate with the lower part  3   a  of the tub  3  by means the first and second pipe  22 ,  32  which both withdraw liquid from the lower part  3   a  of the tub  3  via the filtering device  12 . The filtering device  12  in turn communicates with the lower part  3   a  of the tub  3  by means of the main pipe  17 , as already described above. 
     The first pipe  22  is connected to a first outlet  72  of the filtering device  12  and the second pipe  32  is connected to a second outlet  62  of the filtering device  12 . 
     The first and the second recirculation pumps  21 ,  31 , therefore, are arranged downstream the filtering device  12  and, if advantageously provided, the main pipe  17 . 
     It is underlined that the term “downstream” is referred to the flowing direction of the liquid inside the recirculation circuit during the functioning of the pump; for example saying that the recirculation pump  21  is arranged downstream the filtering device  12  means that while the pump is working the liquid firstly passes through the filtering device  12  and then flows into the recirculation pump  21 . 
     In a first advantageous aspect, the filtering device  12  retains all the undesirable bodies (for example buttons that have come off the laundry, coins erroneously introduced into the laundry washing machine, etc.) which may reach the recirculation pumps  21 ,  31 . 
     This advantageously guarantees a good protection of the recirculation pumps  21 ,  31 . 
     In a further advantageous aspect, the arrangement of the filtering device  12  between the recirculation pumps  21 ,  31  and the main pipe  17  guarantees that the two recirculation circuits  20 ,  30  work substantially independently one to the other. More particularly, the interposition of the filtering device  12  avoids that during the activation of one of, or both, the recirculation pumps  21 ,  31  air is sucked inside the activated pump/s, which would cause malfunctioning of the same. 
     For example, if the first recirculation pump  21  is activated in order to re-circulate liquid from the bottom  3   a  of the tub  3  while the second recirculation pump  31  is off, the presence of filtering device  12  guarantees that the liquid is all substantially withdrawn from the first pipe  17  connected to the bottom  3   a  of the tub  3 , while substantially no liquid is sucked from the second pipe  32  of the second recirculation circuit  30 . This substantially avoids that any liquid and/or air is sucked from the second recirculation circuit  30  and reaches the first recirculation pump  21 . 
     The first recirculation circuit  20  may therefore work properly without any interaction with the second recirculation circuit  30  and the first recirculation pump  21  may work properly without risks of air sucking (which could negatively affect the performances of the pumps). 
     Analogously, if the second recirculation pump  31  is activated in order to re-circulate liquid inside the tub  3  while the first recirculation pump  21  is off, the presence of filtering device  12  guarantees that the liquid is all substantially withdrawn from the first pipe  17  connected to the bottom  3   a  of the tub  3 , while substantially no liquid is sucked from the first pipe  22  of the first recirculation circuit  20 . This substantially avoids that any liquid and/or air is sucked from the first recirculation circuit  20  and reaches the second recirculation pump  31 . 
     The second recirculation circuit  30  may therefore work properly without any interaction with the first recirculation circuit  20  and the second recirculation pump  31  may work properly without risks of air sucking. 
     Also, if both the first and the second recirculation pumps  21 ,  31  are activated, the presence of filtering device  12  guarantees that the liquid is all substantially withdrawn from the first pipe  17  connected to the bottom  3   a  of the tub  3 , while substantially no liquid is sucked from the first pipe  22  and the second pipe  32  of the first and second recirculation circuits  20 ,  30 . This substantially avoids that air is sucked from the first recirculation pump  21  or the second recirculation pump  31 . 
     Due to the presence of the filtering device, therefore, the two recirculation circuits  20 ,  30  may work properly without any interaction between them and therefore without risks of air sucking for the two recirculation pumps  21 ,  31 . 
     In fact, during the activation of one or both the first and second recirculation pumps, when the body of the filtering device  12  is full of washing/rinsing liquid, due to the presence of this liquid also in correspondence to the first outlet  62  and second outlet  72 , air can&#39;t pass from the first outlet  62  of the filtering device  12  to the second outlet  72  or viceversa. 
     Preferably, the first outlet  62  of the filtering device  12  and the second outlet  72  of the filtering device  12  are arranged at opposite side of the filtering device  12  with respect to a central plane C intersecting the filtering device  12  itself, as illustrated in  FIG. 6 . This enhances the independent functioning of the two recirculation circuits  20 ,  30 , because this reciprocal positioning of the first and second outlets allows reducing the risk that one of them is not covered by the washing/rinsing liquid while the latter, sucked by the respective pump, is entering the other outlet. 
       FIG. 7  represents a further advantageous aspect of the present invention. The figure shows the support body  50  of the two recirculation pumps  21 ,  31 , also visible in  FIGS. 2 to 5 . 
     The support body  50  preferably comprises two receiving seats  51 ,  52  where the two recirculation pumps  21 ,  31  are mounted. 
     The support body  50  preferably comprises a first inlet  50   a  for the connection of the first pipe  22 , a first outlet  50   b  for the connection of the first recirculation pipe  23 , a second inlet  50   c  for the connection of the second pipe  32  and a second outlet  50   d  for the connection of the second recirculation pipe  33 . 
     Therefore, the support body  50  comprises a first inlet  50   a  and a first outlet  50   b  for the first recirculation pump  21  and comprises a second inlet  50   c  and a second outlet  50   d  for the second recirculation pump  31 . 
     The support body  50  is advantageously obtained in a single piece construction, preferably by injection moulding. 
     The support body  50  therefore define a completed, integral, unitary member. 
     Installation of the two recirculation pumps  21 ,  31  is therefore simplified. 
     Furthermore, the integral, unitary member of the support body  50  reduces risks of failure and increases reliability of the laundry washing machine  1 . 
     In a further embodiment, not illustrated, the first and the second recirculation circuits may be completely separated from the water outlet circuit: in this case a second filtering device may be advantageously separately associated to the water outlet circuit, while a first common filtering device may be advantageously associated to the two recirculation circuits, substantially as described above. 
     It has thus been shown that the present invention allows all the set objects to be achieved. In particular, it makes it possible to obtain a laundry washing machine with improved washing efficiency with respect to the machines of the prior art. While the present invention has been described with reference to the particular embodiments shown in the figures, it should be noted that the present invention is not limited to the specific embodiments illustrated and described herein; on the contrary, further variants of the embodiments described herein fall within the scope of the present invention.