The solution according to embodiments of the invention generally relates to household and/or professional laundry washing/drying appliances (hereinafter, washer/dryers for the sake of conciseness) operable to perform both washing and drying processes. More particularly, such solution relates to washer/dryers provided with heat pump devices.

Background of the invention

Each washer/dryer generally comprises a laundry chamber configured for housing a laundry load (including articles such as clothes and other textiles), and a (closed) air circulation system adapted, during a drying process, to circulate drying air through the laundry chamber (so as to allow removal of moisture from the laundry load).

In order to achieve that, a class of washer/dryers are provided with heat pump devices.

Broadly speaking, each heat pump device substantially makes use of a refrigerant circuit for effectively transferring thermal energy from a first side at a lower temperature (also referred to as cool side), to a second side at a higher temperature (also referred to as hot side). A common type of heat pump device exploits physical properties of a refrigerant fluid (or refrigerant), which is made to flow in the refrigerant circuit, and comprises a compressor, a pressure-lowering device (e.g. , an expansion valve), and a heat exchanger assembly - i.e. a first heat exchanger (where the refrigerant absorbs heat) and a second heat exchanger (where the refrigerant releases heat), both of them arranged within the air circulation system.

During a drying process performed by a usual washer/dryer provided with heat pump device, the drying air leaving the laundry chamber with decreased temperature and increased humidity (or dump air) with respect to the incoming hot drying air, is passed through the first heat exchanger, where it is further cooled down and dehydrated, and then through the second heat exchanger where, upon reheating, it forms the hot drying air, thereafter the drying air is fed again inside the laundry chamber for evaporating moisture from the laundry load.

However, heat pump-based washer/dryers have being experiencing a certain attractiveness decrease, mainly due to heat pump drawbacks. Indeed, cooling capacity at cool side of the heat pump device could be, or become over time, not high enough to efficiently cool down the dump air, which could result in overheating of the drying air at hot side of the heat pump device. Thus, an undesired overheating of the washer/dryer, and especially of electric/electro-mechanic/electronic components housed therein, is typically experienced, which sets reliability issues. For these reasons, washer/dryers based on other de-moisturizing and heating solutions - e.g. , those based on air-air heat exchanger/heating resistor assembly, are often preferred, wherein heating and cooling capacities balancing can be achieved by adjusting electric power provided to the heating resistor.

In order to substantially avoid (or at least limit) overheating issues afflicting heat pump-based washer/dryers, the Applicant has recently devised an expedient by which relatively fresh ambient air is allowed to enter the washer/dryer (and the air circulation system) and to mix with the drying air (which allows cooling down thereof), and a certain amount of compensation air is allowed to exit the air circulation system (and to vent outside the washer/dryer) for compensating the ambient air added thereto. Said compensation air is not re-circulated through the laundry chamber but, in fact, exhausted outside the washer/dryer.

According to Applicant expedient, compensation air is channeled through a washing products dispensing conduit (that, during a washing process in standard washer/dryers, typically allows dispensing washing products into the laundry chamber from a washing products loading tray), and is vented outside the washer/dryer through the loading tray. This allows avoiding excessive amount of space (and costs) than other possible compensation air venting approaches (e.g. , provision of a dedicated venting arrangement).

Summary of the Invention

The Applicant has found that, although providing optimal results against washer/dryer overheating, while avoiding any increases of space amounts and/or costs, such expedient could prove not fully satisfactory.

Indeed, the Applicant has noticed that the compensation air leaving the laundry chamber, after having dried laundry, and flowing up to the washing product dispensing conduit carries, with it, fluff (such as lint and other residual laundry load fabrics).

Thus, fluff may be dispersed partly within the washer/dryer and partly outside the washer/dryer, and/or it may accumulate within the loading tray, and mix to the washing products upon loading thereof into the loading tray. This could impair washing process.

The Applicant has faced the problem of devising a satisfactory solution able to overcome such drawbacks.

In particular, one or more aspects of the solution according to specific embodiments of the invention are set out in the independent claims, with advantageous features of the same solution that are indicated in the dependent claims (with any advantageous feature provided with reference to a specific aspect of the solution according to an embodiment of the invention that applies mutatis mutandis to any other aspect thereof).

An aspect of the solution according to one or more embodiments of the invention relates to a laundry washing/drying appliance. The laundry washing/drying appliance comprises a laundry chamber for containing laundry to be washed/dried, an air circulation system adapted to cyclically circulate drying air through the laundry chamber during a drying process, and a washing products dispensing conduit adapted to dispense washing products into the laundry chamber during a washing process. An amount of drying air within the laundry chamber is allowed to leave the air circulation system during the drying process. Said washing products dispensing conduit comprises, along at least part thereof, a water well for holding fluff carried with said amount of drying air down.

According to an embodiment of the invention, the washing products dispensing conduit comprises a bulged conduit portion adapted to be at least partially filled with a predefined amount of water so as to form said water well.

According to an embodiment of the invention, the laundry washing/drying appliance further comprises a control unit configured to cause said predefined amount of water to at least partially fill said bulged conduit portion before starting the drying process.

According to an embodiment of the invention, said control unit is further configured to cause restoring of said predefined amount of water within the water well at predefined time intervals during the drying process.

According to an embodiment of the invention, said predefined time intervals depend on at least one between temperature of said amount of drying air and duration of the drying process.

According to an embodiment of the invention, after the drying process, said control unit is further configured to completely replace said predefined amount of water within the bulged conduit portion so as to allow removal of fluff accumulated therewithin.

According to an embodiment of the invention, the laundry washing/drying appliance further comprises a washing products loading tray fluid ly connected to the washing products dispensing conduit, said amount of drying air flowing, free from fluff, at least partly into said loading tray and hence venting outside the appliance.

According to an embodiment of the invention, the laundry washing/drying appliance further comprises an overflow-preventing system fluidly connected to the laundry chamber for preventing washing products from overflowing out of the appliance, said amount of drying air flowing, free from fluff, at least partly into said overflow-preventing system and hence venting inside the appliance.

According to an embodiment of the invention, the laundry washing/drying appliance further comprises an air duct for allowing ambient air to enter the air circulation system and to mix with the drying air thereby avoiding overheating thereof, said amount of drying air leaving the air circulation system substantially compensating the ambient air added thereinto.

According to an embodiment of the invention, the laundry washing/drying appliance further comprises first and second heat exchangers of a heat pump device arranged within the air circulation system. Thanks to this arrangement, the drying air leaving the laundry chamber with decreased temperature and increased humidity with respect to the incoming drying air is first passed through the first heat exchanger, where it is cooled down and de-moisturized, and then through the second heat exchanger, where it is heated-up and fed again into the laundry chamber.

Another aspect of the solution according to one or more embodiments of the invention relates to a method for operating a laundry washing/drying appliance. The laundry washing/drying appliance comprises a laundry chamber for containing laundry to be washed/dried, an air circulation system adapted to cyclically circulate drying air through the laundry chamber during a drying process, a washing products dispensing conduit adapted to dispense washing products into the laundry chamber during a washing process, an amount of drying air within the laundry chamber being allowed to leave the air circulation system during the drying process. The method comprises forming, along at least part of said washing products dispensing conduit, a water well for holding fluff carried with said amount of drying air down.

According to an embodiment of the invention, the washing products dispensing conduit comprises a bulged conduit portion, and said forming a water well comprises at least partially filling the bulged conduit portion with a predefined amount of water.

According to an embodiment of the invention, said at least partially filling the bulged conduit portion takes place before starting the drying process.

According to an embodiment of the invention, the method further comprises restoring said predefined amount of water within the water well at predefined time intervals during the drying process.

According to an embodiment of the invention, said predefined time intervals depend on at least one between temperature of said amount of drying air and duration of the drying process.

According to an embodiment of the invention, the method further comprises, after the drying process, completely replacing said predefined amount of water within the bulged conduit portion so as to allow removal of fluff accumulated therewithin.

Thanks to the proposed invention, fluff dispersion inside and/or outside the washer/dryer and/or fluff accumulation within the loading tray is substantially avoided, or at least drastically reduced. Thus, mixing between fluff and washing products is prevented, and optimal washing processes can take place.

Brief description of the annexed drawin2S

These and other features and advantages of the invention will be made apparent by the following description of some exemplary and non limitative embodiments thereof; for its better intelligibility, the following description should be read making reference to the attached drawings, wherein:

Figure 1 conceptually shows a cross-sectional view of a washer/dryer according to an embodiment of the invention;

Figure 2A shows a perspective and partly exploded front view of a practical implementation of the washer/dryer of Figure 1 according to an embodiment of the invention;

Figures 2B-2C show top and bottom perspective views with partly removed parts, respectively, of a worktop of the washer/dryer of Figure 2A according to an embodiment of the invention, and

Figure 2D shows a perspective and enlarged view of a part of a washing products dispensing conduit visible in Figure 2C.

Detailed description of preferred embodiments of the invention

With reference to the drawings, Figure 1 conceptually shows a cross- sectional view of a washer/dryer 100 according to an embodiment of the invention.

The washer/dryer 100 comprises a laundry chamber 105 (i.e., a tub and a rotating drum housed therein, not illustrated) adapted to contain a laundry load to be washed/dried, and an air circulating system adapted to cyclically circulate drying air through the laundry chamber 105 (during a drying process). The air circulating system comprises a delivery duct 110 fluidly connected to an input opening INios of the laundry chamber 105 for feeding it with drying air, and a return duct 115 fluidly connected to a main output opening OUT 105 of the laundry chamber 105 for taking moisture-laden drying air deriving from drying process (dump air).

Between (and connecting) the delivery 110 and return 115 ducts, a main duct 120 is provided, which houses first HEi and second HE ₂ heat exchangers (e.g. , evaporator and condenser members, respectively) of a heat pump device, as well as a motor-driven fan 125, e.g. arranged downstream the second heat exchanger HE ₂ . As usual, under fan 125 action, the dump air leaving the laundry chamber 105 with decreased temperature and increased humidity with respect to the incoming hot drying air, is first passed (through the return duct 115) through the first heat exchanger HEi, where it is further cooled down and de-moisturized (heat pump cool side). The de-moisturized air is then passed through the second heat exchanger HE ₂ (heat pump hot side), where it is heated-up, thereafter the corresponding hot, de- moisturized air (i.e. , the drying air), is fed again (through the delivery duct 110) into the laundry chamber 105.

In order to compensate insufficient cooling capacity at cool side with respect to heating capacity at hot side, which could result in dangerous overheating - especially of electric/electro-mechanic/electronic components (such as the control unit CU that is typically configured to manage washer/dryer 100 operation) arranged near or within the air circulation system - a secondary air duct 130 is provided that fluidly connects the air circulation system with the surrounding environment - preferably, as illustrated, with the outside of the washer/dryer 100.

Therefore, by means of the secondary air duct 130, relatively cool ambient air

AAIR is taken from the outside of the washer/dryer 100 and fed/channeled into the air circulation system. In order to achieve that, the secondary air duct 130 fluidly connects the outside of the washer/dryer 100 with the main duct 120, at a proper input region thereof - preferably, at (e.g. , after, as illustrated) the second heat exchanger HE ₂ , so that no ambient air AAIR treatment is required by the heat pump device, thus resulting in low power consumption thereof. Anyway, different main duct 120 input region arrangements are possible, for example between the first HEi and second HE ₂ heat exchangers, or at (e.g. , before) the first heat exchanger HEi.

The ambient air AAIR entering the air circulation system mixes with (thereby cooling down) the (drying) air circulating therewithin. This avoids overheating issues.

A secondary output opening OUTios,s of the laundry chamber 105 is provided for allowing a predefined amount of the dump air within it to leave the air circulation system (and to vent outside and/or inside the washer/dryer 100), so as to substantially compensate/balance the ambient air AAIR added thereinto. In order to achieve compensation, the amounts of drying air allowed to leave the air circulation system (hereinafter, compensation air CAIR) and the amount of ambient air AAIR allowed to enter thereinto should be made substantially equal (e.g. , by properly shaping and sizing the secondary air duct 130 and the secondary output opening OUTi ₀ s,s one another).

In the example at issue, venting of the compensation air CAIR takes place by channeling, wherein a venting duct 135 is provided that fluidly connects the secondary output opening OUTi ₀ s,s of the laundry chamber 105 to the surrounding environment.

The venting duct 135 may be a dedicated duct/path/channel, or it may advantageously comprise (as herein illustrated) a washing products dispensing conduit that, in conventional washer/dryers, allows dispensing washing products from a washing products loading tray 140. In other words, the same washing products dispensing conduit that, during a washing process, allows feeding the laundry chamber 105 with the washing products, is also used, in the example at issue, to allow the compensation air CAIR to leave the air circulation system (and preferably, to be vented outside the washer/dryer 100) during a drying process. As should be promptly apparent, flowing of the compensation air CAIR up to the washing products dispensing conduit 135 is allowed by proper fan 125 arrangement along the air circulation system (as herein illustrated) - on the contrary, in the known solutions, fan arrangement is instead intended to generate air depressions at the main output opening OUT ₁₀₅ causing the dump air to be blown mainly (theoretically, only) into the return duct 115.

Venting of the compensation air C _AIR outside the washer/dryer can take place through the loading tray 140, both when, in order to allow washing products loading, it is opened, and when it is closed (as better discussed in the following). In both case, the fluff-laden compensation air C _AIR leaving the laundry chamber 105 and flowing up to the washing products dispensing conduit 135 may cause fluff to accumulate within, thereby dirtying, the loading tray 140. Such fluff may mix to washing products and negatively affect washing process. In addition, fluff dispersed outside the washer/dryer can dirt the ambient where the washer/dryer is placed. In order to avoid such events, or at least limit them, the washing products dispensing conduit 135 comprises, along at least part thereof, a water well 145 for holding fluff carried with the compensation air C _AIR down (as will be better discussed in the following).

A practical implementation of the washer/dryer 100 is shown, according to an embodiment of the invention, in the perspective and partly exploded front view of Figure 2 A (which will be discussed with joint reference to Figure 1). Hereinafter, references denoting components of the washer/dryer 100 in their conceptual representation of Figure 1 will also denote the same components in their practical implementation represented from Figure 2A on.

The washer/dryer 100 comprises a substantially parallepiped-shaped cabinet 205, having a front panel 205p, two side panels 205s (only one visible in the figure), and a bottom panel. The cabinet 205 encloses an inner compartment (not visible) housing the laundry chamber 105 and accessible through an access door 210 (shown in closed configuration).

A top panel 205χ closes the cabinet 205 from above, and defines a ready-to- mount worktop incorporating/housing the air circulation system. In this respect, reference will be also made to Figures 2B-2C, the latter showing, according to an embodiment of the invention, top and bottom perspective views with partly removed parts, respectively, of the worktop 205χ. The worktop 205χ comprises, at a front thereof, the washing products loading tray 140 (shown in the closed configuration), and a removable filter unit F, preferably arranged on the washing products loading tray 140. The filter unit F is configured to filter the dump air from fluff before being passed through the first HEi and second HE ₂ heat exchangers.

The worktop 205χ comprises a, e.g. a plastic, base element 215 shaped and sized so as to define a number of housing sections adapted to house corresponding components of the air circulation system, and a cover assembly (globally denoted by number reference 220) for top covering the base element 215 and delimiting air paths therebetween (as discussed below).

Preferably, the base element 215 comprises housing sections 215|., 215HEI, 215IIK ₂ , for housing the filter unit F, the first heat exchanger HEi, and the second heat exchanger HE ₂ , respectively. As visible in the figures, such housing sections 215 _F , 215||i:i. 215JJE ₂ take most of a worktop top surface STOP, exception made for (left and right) corner regions of the base element 215 (intended to other purposes, as discussed below). A first covering panel 220i of cover the assembly 220 (Figure 2A) covers the base element 215 with the exception of the left corner region thereof - the space between the base element 215 (i.e. , the housing sections 215JJEI, 215 _H E ₂ ) and the first covering panel 220i delimiting an air path that substantially identifies, together with the air path through the filter unit F, the main duct 120. A second covering panel 220 ₂ is instead provided on the first covering panel 220i for aesthetical issues.

The base element 215 comprises, e.g. at a substantially central part of the housing section 215HE ₂ , a base opening 225, which is fluidly connected to the fan 125 (e.g. , rigidly fixed to the base element 215, underneath it) and to the delivery duct 110 for allowing the drying air to be fed into the laundry chamber 105. Preferably, the base opening 225 opens down to a fan 125 input, whereas the delivery duct 110, arranged underneath the base element 215 as well, has a first end connector for connection with a fan 125 output, and a second end connector (for example, an elongated-shaped connector, as illustrated) for connection with an opening of a bellow (not shown) that, as usual in washer/dryers, seals gap between the drum and the access door 210.

The base element 215 also comprises, e.g. at the left corner region thereof, a further base opening 230, which allows connection of the return duct 115 (carrying the dump air within it) from the output opening OUT1 ₀ 5 of the laundry chamber 105 to the filter unit F.

As better discussed in the following, the base opening 230 also allows passage of un-channeled air circulating within the washer/dryer 100 (outside the air circulating system).

During a drying process, the dump air leaving the laundry chamber 105 is first fed (through the return duct 115) through the filter unit F, and the filtered dump air output therefrom is then passed through the first heat exchanger HEi, where it is de-moisturized (with the condensed moisture that is properly collected and drained by a slot grid 235 of the base element 215 on which the first heat exchanger ΗΕχ rests). The de-moisturized air is then passed through the second heat exchanger HE ₂ , where it is heated-up, thereafter such drying air is fed again (through the base opening 225, the fan 125 and the delivery duct 110) into the laundry chamber 105 (i.e. , from a front thereof through the bellow opening).

The base element 215 comprises (e.g. , at the right corner thereof) an air passage 240 (preferably, an air grid vertically extending between opposite top STOP and bottom SBOTTOM surfaces of the base element 215) for allowing input of the ambient air AAIR, and (e.g. , at the left corner thereof) a further air passage 245, similar to the air passage 240, for allowing un-channeled air within the cabinet 205 (such as further ambient air intended to cool down the compressor heat pump) to be vented outside the washer/dryer 100.

As best visible in Figure 2B, the base element 215 further comprises a (preferably, bottleneck) portion 250 fluidly connecting the housing section 215HE ₂ (or any other main duct 120 input region, as discussed above) to the air passage 240, so as to allow the ambient air AAIR to be channeled into the air circulation system and to mix with the drying air. Thus, the air passage, 240, the bottleneck portion 250 and the space between the base element 215 (i.e. , the right corner region thereof) and the first covering panel 220i identify, as a whole, the secondary air duct 130.

As discussed above, the drying air/ambient air AAIR mixture is fed to the laundry chamber 105, thereafter a predefined amount thereof (compensation air CAIR) is allowed to flow into the loading tray 140 (free from fluff, thanks to the water well 145 provided along the washing products dispensing conduit 135) and hence vented outside the washer/dryer 100 (as discussed herebelow).

Preferably, assuming a closed configuration of the loading tray 140 during the drying process, at least part of the compensation air CAIR leaving the laundry chamber 105 and flowing, through the washing products dispensing conduit 135, up to the loading tray 140 is vented through interstices of the loading tray 140 (not distinguishable) allowing opening/closing movements thereof.

Preferably, compensation air CAIR venting is further achieved by means of an overflow-preventing system typically provided in washer/dryers for preventing liquids (e.g. , washing products and/or water) from overflowing out of the washer/dryer 100, for example through the loading tray 140, upon a fault occurrence (e.g. , water pump closure fail). The overflow-preventing system, per se well known in the art, comprises a draining channel 155 (part of which visible in Figure 2C), preferably arranged at a side of the loading tray 140 and at predefined height. When, as a result of a fault, the liquids, rising up within the laundry chamber 105, reach the loading tray 140, they reach a limit level (given by said predefined height), and the exceeding liquids are drained (through the draining channel 155) to a proper liquid vessel (not shown) arranged within the washer/dryer 100, where a liquid detection system (also not shown) is provided. Upon detection of a predefined liquids amount, the liquid detection system completely stops washer/dryer 100 operation, thereby preventing liquids from overflowing out of the washer/dryer 100 via the loading tray 140 and from causing flooding of the user premises where the washer/dryer 100 is placed.

Thus, during normal operation of the washer/dryer 100 the compensation air CAIR (or a part thereof) can flow (free from fluff, thanks to the water well 145) through the overflow-preventing system 155, and vent inside the washer/dryerlOO.

As visible in Figure 2C, the washing products dispensing conduit 135 preferably comprises a bulged conduit portion 260 adapted to be at least partially filled with a predefined amount of water so as to form said water well 145 (in this respect, see also Figure 2D, the latter showing a perspective, enlarged view of a part of the washing products dispensing conduit 135).

The washing products dispensing conduit 135 comprises a first end opening 135i with associated a first manifold adapted to be connected to the secondary output opening OUTios,s of the laundry chamber 105, and a second end opening 135 ₂ with associated a second manifold adapted to be coupled to the washing products loading tray 140 (e.g. , by means of a straight conduit portion, visible in Figure 2C).

Preferably, as illustrated, the washing products dispensing conduit 135 is shaped such as the first 135χ second 135 ₂ end openings are sufficiently above a water well maximum level ML (substantially given by bulged conduit portion 260 specific geometry) to avoid water overflowing from the water well 145 during the drying process.

Upon compensation air CAIR flowing into the washing products dispensing conduit 135 (specifically, upon compensation air CAIR flowing through the free space of the washing products dispensing conduit 135 above the water well 145 and upon compensation air CAIR skimming over water well 145 surface), fluff is held by the water well 145. Thus, the compensation air CAIR is allowed to get out from the loading tray 140 free from fluff.

Advantageously, the control unit CU of the washer/dryer 100 is configured to manage water well 145 as well.

Preferably, the control unit CU is configured to cause a predefined amount of water to fill (until the water well maximum level), or at least partially fill, said bulged conduit portion 260 before starting the drying process.

Moreover, in order to compensate water well 145 evaporation over time due to compensation air CAIR heat, the control unit CU may be also configured to cause periodic restoring of (the predefined amount of water of) the water well 145 during the drying process, preferably at predefined time intervals. Such predefined time intervals may be pre-set (e.g. , by the washer/dryer 100 manufacturer) or dynamically set (for example, by a suitable logic of the control unit CU) according to expected and/or detected compensation air CAIR temperature and/or drying process duration - indeed, compensation air CAIR temperature and/or drying process duration determine evaporation speed of the water well 145.

Finally, after the drying process, the control unit CU may also be configured to completely replace said predefined amount of water within the bulged conduit portion 260, so that removal of fluff accumulated therewithin is allowed. By way of example only, replacing of the predefined amount of water can be achieved by means of controlled water injections into the washing products dispensing conduit 135 - just as for common washing processes.

Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply to the solution described above many logical and/or physical modifications and alterations. More specifically, although the invention has been described with a certain degree of particularity with reference to preferred embodiments thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible. In particular, different embodiments of the invention may even be practiced without the specific details (such as the numeric examples) set forth in the preceding description for providing a more thorough understanding thereof; on the contrary, well known features may have been omitted or simplified in order not to obscure the description with unnecessary particulars. Moreover, it is expressly intended that specific elements and/or method steps described in connection with any disclosed embodiment of the invention may be incorporated in any other embodiment as a matter of general design choice.

Moreover, analogous considerations apply if the washer/dryer has a different structure or comprises equivalent components, or it has other operating features. In any case, any component thereof may be separated into several elements, or two or more components may be combined into a single element; in addition, each- component may be replicated for supporting the execution of the corresponding operations in parallel. It should also be noted that any interaction between different components generally does not need to be continuous (unless otherwise indicated), and it may be both direct and indirect through one or more intermediaries.

Although in the description explicit reference has been made to a worktop integrating the air circulation system, this should not be construed limitatively. Indeed, the principles of the invention may also be applied to conventional washer/dryers wherein the air circulation system is "distributed" within the inner compartment.

Moreover, although in the present description explicit reference has been made to a washer/dryer whose moisture removal from the dump air is carried out by means of an heat pump device, the principles of the present invention also apply to any other moisture condensing unit suitable for the purpose (e.g. , an air-air heat exchanger).

Finally, the solution according to an embodiment of the invention lends itself to be implemented through an equivalent method (by using similar steps, removing some non-essential steps, or adding additional optional steps); moreover, the steps may be performed in a different order, in parallel or overlapped (at least in part).