AU2014314258A1

AU2014314258A1 - Laundry appliance having overheating preventing system

Info

Publication number: AU2014314258A1
Application number: AU2014314258A
Authority: AU
Inventors: Andrea Contarini; Massimo Viero
Original assignee: Electrolux Appliances AB
Current assignee: Electrolux Appliances AB
Priority date: 2013-08-30
Filing date: 2014-08-27
Publication date: 2016-03-10
Anticipated expiration: 2034-08-27
Also published as: EP2843119A1; CN105492681A; AU2014314258B2; EP2843119B1; WO2015028500A1; CN105492681B

Abstract

The solution according to one or more embodiments of the invention relates to a laundry appliance (500) comprising a cabinet (505), a laundry chamber (105) enclosed within the cabinet (505) for containing laundry to be dried, and a worktop (505

Description

WO 2015/028500 PCT/EP2014/068152 1 TITLE: LAUNDRY APPLIANCE HAVING OVERHEATING PREVENTING SYSTEM Field of the invention The solution according to embodiments of the invention generally relates to household and/or professional laundry treating appliances configured for performing drying operations (e.g., laundry washing/drying appliances and laundry drying 5 appliances, hereinafter both referred to as laundry appliances for the sake of conciseness). More particularly, such solution relates to laundry appliances provided with heat pump devices. Background of the invention 10 Each household and/or professional laundry appliance (such as laundry washing/drying appliance, or washer/dryer, and laundry drying appliance, or dryer) generally comprises a laundry chamber configured for housing a laundry load (including articles such as clothes and other textiles) and for causing drying air circulating therethrough to remove moisture from the laundry load, e.g. shortly after 15 cleaning/washing thereof. In order to achieve that, a class of laundry appliances 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 20 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 25 exchanger (where the refrigerant absorbs heat) and a second heat exchanger (where the refrigerant releases heat). During drying operation of a usual laundry appliance provided with heat pump device, the air leaving the laundry chamber with decreased temperature and increased humidity (or dump air) with respect to the incoming hot air (i.e., the drying 30 air), is passed through the first heat exchanger, where it is further cooled down and WO 2015/028500 PCT/EP2014/068152 2 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. 5 Summary of the Invention The Applicant has found that the known and practiced solutions are not satisfactory for modern technological requirements. Indeed, the Applicant has found that cooling capacity at cool side is not high enough to efficiently cool down the dump air, which results in overheating of the 10 drying air at hot side. Thus, an undesired overheating of the laundry appliance, and especially of electric/electro-mechanic/electronic components housed therein, is typically experienced, which sets reliability issues. This also lowers attractiveness of laundry appliances based on heat pump devices over laundry appliances based on other de-moisturizing and heating solutions 15 - e.g., those based on air-air heat exchanger/heating resistor assembly, where heating and cooling capacities balancing can be achieved by adjusting electric power provided to the heating resistor. Many current solutions are provided with a motor-driven fan intended to promote forced ventilation of ambient air on the compressor thereby at least partly 20 cooling it down. However, the Applicant has found that overheating of the other appliance components is not avoided (for example, electronic components, whose safe and optimal operation is guaranteed at relatively low operative temperatures). The Applicant has found that such overheating issues get worse in more critical implementations where the heat exchanger assembly is arranged, together 25 with other components, on a top of the laundry appliance (or worktop). Such drawbacks are exacerbated in most of modern laundry dryers, wherein the increased size of the laundry chambers - intended to meet user requirements of high laundry-capacity for the same, or better, drying performance - involves more drying air to be used. 30 The Applicant has faced the problem of devising a satisfactory solution able WO 2015/028500 PCT/EP2014/068152 3 to overcome the above-discussed 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 5 (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 appliance comprising a cabinet, a laundry chamber 10 enclosed within the cabinet for containing laundry to be dried, and a worktop atop the cabinet. The worktop integrates a drying process air circulation system adapted to continuously circulate process air through the laundry chamber. The worktop comprises an air duct for allowing ambient air to enter the process air circulation system and to mix with the process air thereby avoiding overheating thereof. 15 According to an embodiment of the invention, the laundry chamber comprises an opening for allowing an amount of process air within it to leave the air circulation system thereby substantially compensating the ambient air added thereinto. According to an embodiment of the invention, the worktop comprises a further air passage configured to allow un-channeled air within the cabinet to be 20 vented outside the appliance, at least a part of said amount of process air being vented un-channeled outside the appliance through said further air passage. According to an embodiment of the invention, the laundry appliance is a washer/dryer operable in washing and/or drying operation modes and comprising a washing products dispensing arrangement fluidly connected to said opening for 25 dispensing, when operated in washing mode, washing products to the laundry chamber. At least a part of said amount of process air is vented channeled outside the washer/dryer through said washing products dispensing arrangement. According to an embodiment of the invention, the laundry appliance further comprises a washing products loading tray, arranged at a front of the worktop, for 30 allowing loading of washing products, the washing products loading tray being WO 2015/028500 PCT/EP2014/068152 4 fluidly connected to the washing products dispensing arrangement. At least part of said amount of process air is vented outside the appliance through interstices of said loading tray allowing opening/closing movements thereof. According to an embodiment of the invention, the laundry appliance is a 5 washer/dryer operable in washing and/or drying operation modes. The appliance further comprises an overflow-preventing system preventing liquids introduced within the laundry chamber from overflowing out of the washer/dryer. At least a part of said amount of process air flowing into said overflow-preventing system and hence venting inside the washer/dryer. 10 According to an embodiment of the invention, the overflow-preventing system is in fluid communication with said further air passage. According to an embodiment of the invention, said washing products dispensing arrangement comprises a downwards protruding pipe portion configured to be filled, during drying operation mode, with a predefined amount of water, so that 15 when said amount of process air is passed through the washing products dispensing arrangement, fluff is held in the water. According to an embodiment of the invention, the worktop houses, along the process air circulation system, first and second heat exchangers of a heat pump device, said air duct allowing the ambient air to enter the process air circulation 20 system through an input region thereof in correspondence of the second or the first heat exchanger. According to an embodiment of the invention, the worktop houses, along the process air circulation system, first and second heat exchangers of a heat pump device, said air duct allowing the ambient air to enter the process air circulation 25 system through an input region thereof between the first and second heat exchangers. According to an embodiment of the invention, said air duct comprises an enlarged portion acting as a resonant cavity suppressing/dampening acoustic waves within it caused by ambient air flow. According to an embodiment of the invention, said air duct comprises first 30 and second sound suppressing/dampening portions for suppressing/dampening WO 2015/028500 PCT/EP2014/068152 5 acoustic waves caused by ambient air flow, the first and second suppressing/dampening portions being spaced apart from each other so as to define an air gap therebetween for ambient air flow. According to an embodiment of the invention, said air duct comprises an air 5 passage provided at a panel of said cabinet, said ambient air being admitted within the cabinet through said air passage and hence through said air duct. According to an embodiment of the invention, said air passage extends between top and bottom surfaces of a worktop base, and at a rear portion thereof, the first and second sound suppressing/dampening portions being arranged on the top 10 surface of the worktop base such that the ambient air, after entering said air passage, is channeled within said air gap. According to an embodiment of the invention, the worktop base comprises a bottleneck portion fluidly connecting said air gap to the ambient air input region of the air circulation system, said bottleneck portion preventing the process air from 15 diffusing to the surrounding environment through the air gap and the air passage. Thanks to the proposed invention, overheating issues are substantially avoided, or at least drastically reduced. This increases laundry appliance reliability, and attractiveness of heat pump-based laundry appliances. 20 Brief description of the annexed drawings These and other features and advantages of the present 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: 25 Figures 1-4 schematically show an air circulating system according to embodiments of the invention; Figure 5A shows a perspective and partly exploded front view of a laundry appliance according to an embodiment of the invention; Figure 5B shows a perspective rear view of a part of the laundry appliance of 30 Figure 5A according to an embodiment of the invention; WO 2015/028500 PCT/EP2014/068152 6 Figures 5C-5D show top and bottom perspective views with partly removed parts, respectively, of a worktop of the laundry appliance of Figure 5A according to an embodiment of the invention, and Figures 5E-5F show a top view with partly removed parts of the worktop of 5 Figures 5C-5D, and a close-up view thereof, respectively, according to an embodiment of the invention. Detailed description of preferred embodiments of the invention With reference to the drawings, Figures 1-4 conceptually show an air circulating system 100-400 according to embodiments of the invention. 10 The air circulating system 100-400 is adapted to continuously, i.e. cyclically, circulate drying air through a laundry chamber 105 (i.e., a tub and a rotating drum housed therein, not illustrated) containing a laundry load to be dried. Specifically, the air circulating system 100-400 comprises a delivery duct 110 fluidly connected to an input opening IN 105 of the laundry chamber 105 for supplying it with drying air, and 15 a return duct 115 fluidly connected to a main output opening OUT 105 of the laundry chamber 105 for taking moisture-laden 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 HE 1 and second HE 2 heat exchangers (e.g., evaporator and condenser members, respectively) of a heat pump device, as well as a 20 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 HE 1 , where it is further cooled down and de-moisturized (heat pump cool 25 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 30 to heating capacity at hot side, which could result in dangerous overheating WO 2015/028500 PCT/EP2014/068152 7 (especially of electric/electro-mechanic/electronic components, not shown, arranged near or within the air circulation system 100-400), a secondary air duct 130-430 is provided that fluidly connects the air circulation system 100-400 with the appliance surrounding environment - preferably, with the outside of a laundry appliance where 5 the air circulation system 100-400 is intended to be used. Therefore, by means of the secondary air duct 130-430, relatively cool ambient air AAIR is taken from the outside of the laundry appliance and supplied/channeled into the air circulation system 100-400. The ambient air AAIR entering the air circulation system 100-400 mixes with (thereby cooling down) the 10 air circulating therewithin. This avoids overheating issues. As illustrated, Figures 1-3 embodiments differ from one another for the air circulation system 100-300 input region where the ambient air AAIR is allowed to enter - i.e., input region in correspondence of the second heat exchanger HE 2 , input region between the first HE 1 and second HE 2 heat exchangers, or input region in 15 correspondence of the first heat exchanger HE 1 , respectively. The secondary air ducts 130-330 have been illustrated as having same shapes and arrangements, but reciprocally different lengths (depending, in the example at issue, on the air circulation system 100-300 input regions which they are fluidly connected to), it being understood that shape, size and arrangement thereof, not limiting for the 20 invention, may be chosen according to design options of the air circulation system 100-300 (as progressively detailed when introducing design issues thereof) and of the corresponding laundry appliance (as better detailed when discussing a practical implementation thereof). As far as Figure 4 embodiment is concerned, the ambient air AAIR is allowed to enter through the air circulation system 400 input region in 25 correspondence of the second heat exchanger HE 2 (as for Figure 1 embodiment). A secondary output opening OUT 105 ,s of the laundry chamber 105 is provided for allowing an amount of dump air within it to leave the air circulation system 100 400 (and to vent, at least in part, outside the laundry appliance), so as to substantially compensate/balance the ambient air AAIR added thereinto. In order to achieve 30 compensation, the amounts of dump air allowed to leave the air circulation system WO 2015/028500 PCT/EP2014/068152 8 100-400 (hereinafter, compensation air CAIR) and of ambient air AAIR allowed to enter thereinto should be made substantially equal (e.g., by properly shaping and sizing the secondary air duct 130-430 and the secondary output opening OUT 10 5 ,s one another). 5 Venting of the compensation air CAIR may take place by any suitable approach, not limiting for the invention. For example, the compensation air CAIR may be vented un-channeled - as for cooling air typically used for cooling down heat pump compressor, not shown - and/or channeled. Figure 4 illustrates compensation air CAIR venting by channeling, wherein a 10 venting duct 435 is provided that fluidly connects the secondary output opening

OUT

10 5 ,s of the laundry chamber 105 to the environment surrounding the laundry appliance. The venting duct 435 may be a dedicated duct/path/channel, or it may advantageously comprise (as illustrated from Figure 4 on) a washing products 15 dispensing arrangement that, in a laundry appliance performing both washing and drying functions (hereinafter, washer/dryer), allows dispensing washing products from a washing products loading tray 440. In other words, the same dispensing arrangement that, during a washing-mode operation of the washer/dryer, allows feeding the laundry chamber 105 with washing products, is also used, in the example 20 at issue, for venting at least a part of compensation air CAIR outside the washer/dryer during a drying-mode operation thereof. Thus, venting of at least a part of compensation air CAIR outside the washer/dryer can take place from the loading tray 440 (both when, in order to allow washing products loading, it is opened, and when it is closed, as better discussed in 25 the following). Ambient air AAIR and compensation air CAIR flows may originate excessive sound/noise issues, thus sound/noise suppression/dampening may be required. In order to achieve that, the secondary air duct 430 is preferably provided with an enlarged portion 445 that, upon proper sizing, acts as a resonant cavity 30 suppressing/dampening acoustic waves within it at selected frequencies (and/or WO 2015/028500 PCT/EP2014/068152 9 frequencies ranges). Additionally (as illustrated), or alternatively, first 4451 and second 4452 sound suppressing/dampening portions may be provided (e.g., made of aluminum foam or any other suitable sound absorbing or soundproof materials). The first 4451 and second 4452 suppressing/dampening portions are preferably spaced 5 apart from each other so as to define an air gap therebetween for ambient air AAIR flow (with such air gap that, in terms of air path, is part of the secondary air duct 430), for example (as illustrated) arranged at top and bottom recessed walls, respectively, of the cavity 445. A washer/dryer 500 incorporating an air circulation system (e.g., the air 10 circulation system 400) is shown, according to an embodiment of the invention, in the perspective and partly exploded front view of Figure 5A (which will be discussed with joint reference to Figure 4). As above-mentioned, it is understood that the principles of the invention may be applied to any other laundry appliance generally configured for performing laundry drying operations, and that reference to 15 a washer/dryer is made only as a preferred and complete embodiment. Hereinafter, references denoting components of the air circulation system 400 in their schematic representation of Figure 4 will also denote the same components in their practical implementation in the washer/dryer 500. The washer/dryer 500 comprises a substantially parallepiped-shaped cabinet 20 505, having a front panel 505F, two side panels 505s (only one visible in the figure), and a bottom panel. The cabinet 505 encloses an inner compartment housing the laundry chamber 105 and accessible through an access door 510 (shown in closed configuration). A top panel 505T closes the cabinet 505 from above, and defines a ready-to 25 mount worktop incorporating/housing the air circulation system. In this respect, reference will be also made to Figure 5B, showing a perspective rear view of a part of the washer/dryer 500, to Figures 5C-5D, showing top and bottom perspective views with partly removed parts of the worktop 505T, and to Figures 5E-5F, showing a top view and a close-up view, respectively, of the worktop 505T. 30 The worktop 505T comprises, at a front thereof, the washing products loading WO 2015/028500 PCT/EP2014/068152 10 tray 440 (shown in the closed configuration), and a removable filter unit F, preferably arranged on the washing products loading tray 440. The filter unit F is configured to filter the dump air (from fluff and other residual laundry load fabrics) before being passed through the first HE 1 and second HE 2 heat exchangers. 5 The worktop 505T comprises a, e.g. a plastic, base element 515 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 520) for top covering the base element 515 and delimiting air paths therebetween (as discussed below). 10 Preferably, the base element 515 comprises housing sections 515F, 515HE1, 515HE2, for housing the filter unit F, the first heat exchanger HE 1 , and the second heat exchanger HE 2 , respectively. As visible in the figures, such housing sections 515F, 515HE1, 515HE2 take most of a worktop top surface STOP, exception made for (left and right) corner regions of the base element 515 (intended to other purposes, as 15 discussed below). A first covering panel 5201 of the cover assembly 520 (Figure 5A) covers the base element 515 with the exception of the left corner region thereof - the space between the base element 515 (i.e., the housing sections 515HE1, 515HE2) and the first covering panel 5201 delimiting an air path that substantially identifies, together with filter unit F air path, the main duct 430. A second covering panel 5202 20 is instead provided on the first covering panel 5201 for aesthetical issues. The base element 515 comprises, e.g. at a substantially central part of the housing section 515HE2, a base opening 525, which is fluidly connected to the fan 125 (e.g., rigidly fixed to the base element 515, underneath it) and to the delivery duct 110 for allowing the drying air to be supplied into the laundry chamber 105. 25 Preferably, the base opening 525 opens down to a fan 125 input, whereas the delivery duct 110, arranged underneath the base element 515 as well, has a first end connector (not visible) 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 30 between the drum and the access door 510.

WO 2015/028500 PCT/EP2014/068152 11 The base element 515 also comprises, e.g. at the left corner region thereof, a further base opening 530, which allows connection of the return duct 115 (carrying the dump air within it) from the output opening OUT 1 05 of the laundry chamber 105 to the filter unit F. 5 As better discussed in the following, the base opening 530 also allows passage of un-channeled air circulating within the washer/dryer 500 (outside the air circulating system). During drying-mode operation of the washer/dryer 500, the dump air leaving the laundry chamber 105 is first supplied (through the return duct 115) through the 10 filter unit F, and the filtered dump air output therefrom is then passed through the first heat exchanger HE 1 , where it is de-moisturized (with the condensed moisture that is properly collected and drained by a slot grid 535 of the base element 515 on which the first heat exchanger HE 1 rests). The de-moisturized air is then passed through the second heat exchanger HE 2 , where it is heated-up, thereafter the drying 15 air is supplied again (through the base opening 525, the fan 125 and the delivery duct 110) into the laundry chamber 105 (i.e., from a front thereof through the bellow opening). The air duct 430 comprises an air passage 540 for allowing admission/access of ambient air AAIR into the washer/dryer cabinet 505. Such air passage 540 may be 20 provided at any suitable panel 505T,505F,505s of the cabinet 505, and at any proper position thereof. Advantageously, as illustrated, such air passage 540 is provided at the worktop 505T, as the latter integrating the air circulation system within it (however, nothing prevents from providing the air passage 540 at the front 505F or side 505s 25 panels, in which case joint members could be necessary for joining the air passage 540, at the front 505F or side 505s panels, to the input region of the air circulation system 400, at the worktop 505). More preferably, the air passage 540 is provided at the base element 515 of the worktop 505T. In the exemplary illustrated embodiment, the air passage 540 is 30 configured as an air grid vertically extending (with respect to the floor where the WO 2015/028500 PCT/EP2014/068152 12 washer/dryer 500 is intended to rest) between opposite top STOP and bottom SBOTTOM surfaces of the base element 515 (however, any other configuration deemed suitable for the purpose can be conceived). Preferably, as shown in Figure 5B, the air passage 540 is placed at a rear 5 portion (e.g., at the right corner) of the base element 515 that, upon worktop 505T mounting, protrudes with respect to washer/dryer 500 back. This generates a gap between the washer/dryer 500 back and a vertical wall (not shown) which the washer/dryer 500 is intended to lean against, which allows adequate ambient air AAIR intake. Figure 5B also shows, at the left corner of the base element 515, a further air 10 passage 545, similar to the air passage 540, configured to allow un-channeled air within the cabinet 505 to be vented outside the washer/dryer 500 (as indicated by arrows exiting from the worktop 505T air passage 545). Such un-channeled air may comprise (as in many washer/dryers) further ambient air intended to cool down the compressor heat pump, and/or (as discussed above for some contemplated 15 embodiments of the invention) the compensation air CAIR Air passage 540 arrangement should take into account air passage 545 arrangement. Preferably, as illustrated, the air passages 540 and 545 are arranged far enough to substantially avoid, or at least limit, that the air exiting the air passage 545 gets back into the air passage 540 thereby frustrating drying air cooling. 20 As visible in Figures 5A and 5C, the first 4451 and second 4452 sound suppressing/dampening portions are arranged on the top surface STOP of the worktop base 515 such that the ambient air AAIR, after entering the air passage 540, are channeled within the air gap defined by them. As best visible in Figures 5E and 5F, the ambient air AAIR is then channeled 25 into a bottleneck portion 550 of the base element 515 fluidly connecting the air gap to the housing section 515HE2 (or to any other input region of the air circulation system 400, as discussed above), thereafter mixing between ambient air AAIR and drying air takes place. Thus, the air passage 540, the air gap between the first 4451 and second 4452 sound absorbing portions and the bottleneck portion 550 act, as a 30 whole, as the secondary air duct 430.

WO 2015/028500 PCT/EP2014/068152 13 Arrangement of the air passage 540, as well as sizing and shaping of the air gap and of the bottleneck portion 550, are adapted to meet specific design options. For example, a sufficiently narrow and curved bottleneck portion (as the illustrated bottleneck portion 550), is able to prevent the drying air from spreading without 5 control through the secondary air duct 430. Moreover, air passage 540, air gap and/or bottleneck portion 550 reciprocal arrangements, shaping and sizing could meet local pressures differences issues. For example, a pressure at the input region of the air circulation system 100 sufficiently lower than ambient pressure (outside the washer/dryer 500, where the ambient air 10 AAIR is taken from) would allow ambient air AAIR taking/drawing by pressure unbalance, without requiring any additional fans. As discussed above, the drying air/ambient air AAIR mixture is supplied to the laundry chamber 105, thereafter at least a part thereof (compensation air CAIR) is vented outside the washer/dryer 500 through the washing products dispensing 15 arrangement 435 and the loading tray 440 connected thereto (as discussed herebelow). Preferably, assuming a closed configuration of the loading tray during drying operation of the washer/dryer 500, at least part of the compensation air CAIR leaving the laundry chamber 105 and flowing, through the dispensing arrangement 435, up to 20 the loading tray 440 is vented through interstices of the loading tray 440 (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 25 washer/dryer 500, for example through the loading tray 440, 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 555 (part of which visible in Figure 5D), preferably arranged at a side of the loading tray 440 and at predefined height. When, as a result of a fault, the liquids, rising up within the laundry chamber 105, reach the 30 loading tray 440, they reach a limit level (given by said predefined height), and the WO 2015/028500 PCT/EP2014/068152 14 exceeding liquids are drained (through the draining channel 555) to a proper liquid container (not shown) arranged within the washer/dryer 500, 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 500 operation, thereby 5 preventing liquids from overflowing out of the washer/dryer 500 via the loading tray 440 and from causing flooding of the user premises where the washer/dryer 500 is placed. Thus, during normal operation of the washer/dryer 500 the compensation air CAIR (or a part thereof) can flow through the overflow-preventing system, and vent 10 inside the washer/dryer 500. Advantageously, the overflow-preventing system is in fluid communication with the air passage 545, such that, compensation air CAIR (or a part thereof) which has been vented inside the washer/dryer 500, can be exhausted outside the washer/dryer cabinet 505. The fluff-laden compensation air CAIR leaving the laundry chamber 105 and 15 flowing up the washing product dispensing arrangement 435 may cause fluff to accumulate within, thereby dirtying, the loading tray 440. Such fluff may mix to washing products and negatively affect washing operation of the washer/dryer 500. In order to avoid such an event, or at least limit it, the washing products dispensing arrangement 435, preferably in the form of a pipe, is preferably provided 20 with a downwards protruding pipe portion 560 (Figure 5D) adapted to be at least partially filled, during drying operation mode, with a proper amount of water (a water well is thus formed along the compensation air CAIR path). Upon compensation air CAIR flowing into the dispensing arrangement 435, fluff is held by the water well. Thus, the compensation air CAIR is allowed to get out from the loading tray 440 free 25 of fluff. Advantageously, during a same drying operation, several water well filling cycles (so as to compensate water evaporating over time due to compensation air CAIR heat), and/or several water well discharge-and-filling cycles (so as to discharge hot water full of fluff and replace it with a fresh and clean water) may be provided. Naturally, in order to satisfy local and specific requirements, a person skilled 30 in the art may apply to the solution described above many logical and/or physical WO 2015/028500 PCT/EP2014/068152 15 modifications and alterations. More specifically, although the present 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 5 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 10 elements 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 laundry appliance 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, 15 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. 20 Although in the description the air passages have been described as provided at a rear portion of the laundry appliance, this should not be construed limitatively. By way of example only, it is possible to provide implementations wherein the air passages are provided at different cabinet sides, preferably opposite sides, thereof. Finally, although in the present description explicit reference has been made 25 to a laundry appliance whose moisture removal from the process air is carried out by means of a 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).

Claims

1. Laundry appliance (500) comprising a cabinet (505), a laundry chamber (105) enclosed within the cabinet (505) for containing laundry to be dried, and a worktop (505T) atop the cabinet (505), the worktop (505T) integrating a drying 5 process air circulation system (100-400) adapted to continuously circulate process air through the laundry chamber (105), characterized in that the worktop (505T) comprises an air duct (130-430) for allowing ambient air (AAIR) to enter the process air circulation system (100-400) and to mix with the 10 process air thereby avoiding overheating thereof.

2. Laundry appliance (500) according to Claim 1, wherein the laundry chamber (105) comprises an opening (OUT 10 5 ,s) for allowing an amount of process air (CAIR) within it to leave the air circulation system (100-400) thereby substantially 15 compensating the ambient air (AAIR) added thereinto.

3. Laundry appliance (500) according to Claim 2, wherein the worktop (505T) comprises a further air passage (545) configured to allow un-channeled air within the cabinet (505) to be vented outside the appliance, at least a part of said amount of 20 process air (CAIR) being vented un-channeled outside the appliance through said further air passage (545).

4. Laundry appliance (500) according to Claim 2 or 3, wherein the laundry appliance is a washer/dryer (500) operable in washing and/or drying operation 25 modes, the washer/dryer (500) comprising a washing products dispensing arrangement (435) fluidly connected to said opening (OUT 1 05 ,s) for dispensing, when operated in washing mode, washing products to the laundry chamber (105), at least a part of said amount of process air (CAIR) being vented channeled outside the washer/dryer (500) through said washing products dispensing arrangement (435). 30 WO 2015/028500 PCT/EP2014/068152 17

5. Laundry appliance (500) according to Claim 4, further comprising a washing products loading tray (440), arranged at a front of the worktop (505T), for allowing loading of washing products, the washing products loading tray (440) being fluidly connected to the washing products dispensing arrangement (435), 5 wherein at least part of said amount of process air (CAIR) is vented outside the appliance through interstices of said loading tray (440) allowing opening/closing movements thereof.

6. Laundry appliance (500) according to any Claim 2 to 5, wherein the 10 laundry appliance is a washer/dryer (500) operable in washing and/or drying operation modes, the appliance (500) further comprising an overflow-preventing system (555) preventing liquids introduced within the laundry chamber (105) from overflowing out of the washer/dryer (500), at least a part of said amount of process air (CAIR) flowing into said overflow-preventing system (555) and hence venting 15 inside the washer/dryer (500).

7. Laundry appliance (500) according to Claims 6 when depending from Claim 3, wherein the overflow-preventing system (555) is in fluid communication with said further air passage (545). 20

8. Laundry appliance (500) according to any Claim from 4 to 7, wherein said washing products dispensing arrangement (435) comprises a downwards protruding pipe portion (560) configured to be filled, during drying operation mode, with a predefined amount of water, so that when said amount of process air (CAIR) is passed 25 through the washing products dispensing arrangement (435), fluff is held in the water.

9. Laundry appliance (500) according to any of the preceding Claims, wherein the worktop (505T) houses, along the process air circulation system 30 (100;400), first (HE 1 ) and second (HE 2 ) heat exchangers of a heat pump device, said WO 2015/028500 PCT/EP2014/068152 18 air duct (130;430) allowing the ambient air (AAIR) to enter the process air circulation system (100;400) through an input region thereof in correspondence of the second or the first heat exchanger (HE 2 ,HE 1 ). 5

10. Laundry appliance (500) according to any Claim from 1 to 8, wherein the worktop (505T) houses, along the process air circulation system (200), first (HE 1 ) and second (HE 2 ) heat exchangers of a heat pump device, said air duct (230) allowing the ambient air (AAIR) to enter the process air circulation system (200) through an input region thereof between the first (HE 1 ) and second (HE 2 ) heat 10 exchangers.

11. Laundry appliance (500) according to any of the preceding Claims, wherein said air duct (430) comprises an enlarged portion (445) acting as a resonant cavity suppressing/dampening acoustic waves within it caused by ambient air (AAIR) 15 flow.

12. Laundry appliance (500) according to any of the preceding Claims, wherein said air duct (430) comprises first (4451) and second (4452) sound suppressing/dampening portions for suppressing/dampening acoustic waves caused 20 by ambient air (AAIR) flow, the first (4451) and second (4452) suppressing/dampening portions being spaced apart from each other so as to define an air gap therebetween for ambient air (AAIR) flow.

13. Laundry appliance (500) according to any of the preceding Claims, 25 wherein said air duct (430) comprises an air passage (540) provided at a panel (505T,505F,505s) of said cabinet (505), said ambient air (AAIR) being admitted within the cabinet (505) through said air passage (540) and hence through said air duct (430). 30

14. Laundry appliance (500) according to Claim 13 when depending from WO 2015/028500 PCT/EP2014/068152 19 Claim 12, wherein said air passage (540) extends between top (STOP) and bottom (SBOTTOM) surfaces of a worktop base (515), and at a rear portion thereof, the first (4451) and second (4452) sound suppressing/dampening portions being arranged on the top surface (STOP) of the worktop base (515) such that the ambient air (AAIR), 5 after entering said air passage (540), is channeled within said air gap.

15. Laundry appliance (500) according to Claim 14 when depending from Claim 9 or 10, wherein the worktop base (515) comprises a bottleneck portion (550) fluidly connecting said air gap to the ambient air input region of the air circulation 10 system (100-400), said bottleneck portion (550) preventing the process air from diffusing to the surrounding environment through the air gap and the air passage (540).