EP2412861A1

EP2412861A1 - Laundry washing and drying machine

Info

Publication number: EP2412861A1
Application number: EP10171465A
Authority: EP
Inventors: Giorgio Coletto; Roberto Mazzocco
Original assignee: Electrolux Home Products Corp NV
Current assignee: Electrolux Home Products Corp NV
Priority date: 2010-07-30
Filing date: 2010-07-30
Publication date: 2012-02-01
Anticipated expiration: 2030-07-30
Also published as: EP2412861B1; RU2011132191A; CN102409507A

Abstract

Laundry washing and drying machine (1) comprising an outer casing (2); a washing tub (3) arranged inside the casing (2); wherein at least the rear wall (3b) of the washing tub (3) is made of plastic material, and it is provided with a seat or recess (18) which extends on the outer face of the rear wall (3b), and with a plurality of reinforcing ribs (19) which are distributed on the outer face of the rear wall (3b) of the washing tub (3), except for the area where the seat or recess (18) is located; the condenser (17) comprises an internal main conduit (21) delimited by the seat or recess (18) and by a lid or cover (20), the internal main conduit is structured so to use the freshwater of the water mains or similar water source as refrigerant for cooling down and dehumidifying the air that the air circulating means (15) draws from the washing tub (3).

Description

The present invention relates to a laundry washing and drying machine.
More specifically, the present invention relates to a front-loading home laundry washing and drying machine, to which the following description refers purely by way of example without implying any loss of generality.
As is known, today's front-loading home laundry washing and drying machines generally comprise:

a substantially parallelepiped-shaped outer boxlike cabinet or casing structured for resting on the floor;
a substantially bell-shaped washing tub which is suspended in floating manner inside the casing via a number of coil springs and shock-absorbers, with the mouth directly facing a laundry loading/unloading through opening realized in the front wall of the casing; and
a porthole door which is hinged to the front wall of the casing to rotate to and from a closing position in which the door rests on the front face of the casing to close the laundry loading/unloading on the front wall and watertight seal the washing tub.

More specifically, the washing tub is suspended substantially horizontally inside the casing with its mouth directly faced to the laundry loading/unloading opening realized on the front wall of the casing, and the laundry washing and drying machine is generally provided with a cylindrical elastically-deformable bellows which connects in watertight manner the mouth of the bell-shaped washing tub to the laundry loading/unloading opening on the front wall of the casing.
In addition to the above, front-loading home laundry washing and drying machines also comprise, inside the boxlike casing:

a substantially bell-shaped cylindrical revolving drum which is structured for housing the laundry to be washed and/or dried, and is housed in axially rotating manner inside the washing tub for rotating about its longitudinal axis;
an electric motor assembly which is located immediately outside of the washing tub, and is structured for driving into rotation, on command, the revolving drum about its longitudinal axis inside the washing tub; and
a closed-circuit, hot-air generator which is structured to circulate inside the washing tub a stream of hot air having a low moisture content, and which flows through the revolving drum and over the laundry inside the drum to rapidly dry the laundry.

More specifically, the closed-circuit, hot-air generator is structured for gradually drawing air from the washing tub; cooling down the air arriving from the washing tub so to extract and retain the surplus moisture in the air; heating the dehumidified air to a predetermined temperature, normally higher than the temperature of the air arriving from the washing tub; and feeding the heated, dehumidified air back into the washing tub, where it flows over the laundry stored inside the revolving drum to rapidly dry said laundry.
As is known, in many currently-marketed models of front-loading home laundry washing and drying machine, the cooling down and dehumidification of the air drawn from the washing tub is performed inside an cold-water condenser which uses the cold freshwater of the water mains as refrigerant.
In the front-loading home laundry washing and drying machine disclosed in EP-2149635 , the cold-water condenser is attached to the rear wall of the washing tub, so that the inlet of the condenser casing directly communicates with the inside of the washing tub, close to the bottom of the latter, and so that the outlet of the condenser casing directly communicates with an electric centrifugal fan which is rigidly fixed on the top of the washing tub. The delivery of the centrifugal fan, in turn, communicates with the mouth of the bell-shaped washing tub via a connecting manifold which houses a resistor dimensioned for rapidly heating up the air flowing therein towards the washing tub.
Despite allowing a considerable reduction of the length of the pipes connecting the injected cold-water condenser to the washing tub with the production costs savings concerned, attaching the cold-water condenser to the rear wall of the washing tub has significantly increased the dimensions of the washing group suspended inside the casing with all problems concerned.
In this type of laundry washing and drying machine, in fact, the appliance casing must be resized in depth so as to house a deeper floatingly-suspended washing group, and therefore it has no more standard dimensions.
Aim of the present invention is to reduce the overall depth of this particular type of washing group, so as to permit said washing group to be housed in a boxlike casing having standard dimensions, possibly also reducing the appliance overall production costs.
In compliance with the above aims, according to the present invention there is provided a laundry washing and drying machine comprising an outer casing structured for resting on the floor and, inside the casing:

a washing tub arranged inside the casing;
a rotatable drum housed in axially rotating manner inside the washing tub and structured for housing the laundry to be washed and/or dried; and
a closed-circuit structured to circulate inside the washing tub a stream of hot air which flows through the rotatable drum and over the laundry stored inside the drum to rapidly dry said laundry;

Furthermore and preferably, though not necessarily, the seat or recess on the outer face of the rear wall of the washing tub has its lower end in direct communication with the inside of the washing tub via a first through opening located close to the bottom of the washing tub, and its upper end in communication with the suction of the air circulating means via a second through opening.
Furthermore and preferably, though not necessarily, the seat or recess on the outer face of the rear wall of the washing tub is a substantially C-shaped seat or recess which extends close to the periphery of said rear wall; and the lid or cover is a substantially flat, C-shaped lid or cover which is dimensioned so to cover said C-shaped seat or recess on the rear wall of the washing tub, and is welded to the rear wall of washing tub so to hermetically close said C-shaped seat or recess for forming, together with the C-shaped seat or recess, a substantially C-shaped, internal main conduit which, in turn, extends inside the rear wall of the washing tub close to the periphery of the latter.
Furthermore and preferably, though not necessarily, the internal main conduit of the condenser is fluidly connected to a delivering pipe adapted to supply both the detergents and/or softeners and the freshwater to be used in the washing cycle and to be channeled into the washing tub through the condenser, the delivering pipe is adapted to supply the freshwater to be used in the drying cycle for cooling down and dehumidifying the air flowing through internal main conduit.
Furthermore and preferably, though not necessarily, the condenser is also provided with an inwards-projecting water slide which protrudes from the inner surface of the internal main conduit immediately upstream of a section of the main conduit which fluidly communicates with a delivering pipe, and is shaped so as to oblige the water arriving from the delivering pipe to form a waterfall which is located approximately in the centerline of said main conduit in order to prevent the cooling water channeled into internal conduit from lapping/licking against the inner surface of conduit while the water flows through the condenser, thereby maximizing the heat exchange between the cooling water and the moisture laden hot air.
Furthermore and preferably, though not necessarily, the lid or cover does not protrude above the crest lines of the reinforcing ribs on the rear wall of the washing tub.
Furthermore and preferably, though not necessarily, the condenser is also provided with an inwards-projecting spoiler which protrudes from the inner surface of the internal main conduit immediately downstream of an inlet of the latter, and is shaped so as to generate strong turbulences in the air flowing between the inlet of the condenser and a section of the main conduit fluidly communicating with the delivering pipe.
Furthermore and preferably, though not necessarily, the condenser is also provided with one or more low-profiled inwards-projecting transversal ribs which are located downstream of a section of the main conduit fluidly communicating with the delivering pipe and protrude from the inner surface of the internal main conduit so as to prevent the water droplets condensed on the inner surface of said main conduit from flowing upwards pushed by the airflow directed towards the suction of the air circulating means.
Furthermore and preferably, though not necessarily, the outer face of the lid or cover is additionally provided with a plurality of reinforcing ribs which are arranged so as to cooperate with the reinforcing ribs on the rear wall of the washing tub to stiffen the rear portion of the washing tub.
Furthermore and preferably, though not necessarily, the inwards-projecting water slide comprises two mutually faced and reciprocally inclined main winglets which protrude from, respectively, the bottom surface of the seat or recess in the rear wall of the washing tub and the inner face of the lid or cover, and which extend one towards the other so as to put the respective distal side edges in abutment one against the other for forming a substantially V-shaped channel which extends inside the internal main conduit approximately up to the center of the local section of the main conduit.
Furthermore and preferably, though not necessarily, the distal side edges of the two main winglets are mutually welded during the welding process that fixes the lid or cover to the rear wall of the washing tub.
Furthermore and preferably, though not necessarily, the inwards-projecting water slide additionally comprises an auxiliary transversal winglet which cantileverly protrudes from the surface of the seat or recess realized on the outer face of the rear wall of the washing tub, immediately above the two main winglets, so as to cover in penthouse-like manner a transversal slit formed between the lateral edge of one of the two main winglets and the surface of the seat or recess on the rear wall of the washing tub.
Furthermore and preferably, though not necessarily, the inwards-projecting spoiler comprises at least a first winglet which protrudes from the bottom of the seat or recess realized in the rear wall of the washing tub, and extends towards the overhanging lid or cover so as to put its distal side edge in substantial abutment against the inner face of said lid or cover, or against the distal side edge of a substantially coplanar second winglet which protrudes from the inner face of said lid or cover.
Furthermore and preferably, though not necessarily, the reinforcing ribs are arranged on the outer face of the rear wall of the washing tub according to a substantially radially-oriented layout roughly centered to the longitudinal axis of the washing tub.
Furthermore and preferably, though not necessarily, the laundry washing and drying machine is provided with a detergent dispenser comprising a container or receptacle which is located inside the casing and is structured for housing an extractable drawer which, in turn, is provided with one or more compartments dimensioned for storing a given amount of detergent and/or softener to be used in the washing cycle; the bottom of said container or receptacle communicating with the inside of the washing tub via said delivering pipe.
Furthermore and preferably, though not necessarily, the washing tub has the mouth directly faced to a laundry loading/unloading opening realized in the front wall of the casing; and in that the laundry washing and drying machine is also provided with a bellows which connects in watertight manner the mouth of the washing tub to the laundry loading/unloading opening on the front wall of the casing.
Furthermore and preferably, though not necessarily, the closed-circuit, hot-air generator additionally comprises: an air duct which connects the delivery of the air circulating means to the washing tub, or to the bellows which connects the mouth of the washing tub to the laundry loading/unloading opening realized in the front wall of the casing; and an electrically-powered air heater which is located inside the air duct, and is structured for rapidly heating up the airflow directed towards the washing tub along said air duct.
Furthermore and preferably, though not necessarily, the air circulating means (15) are fixed approximately on the top of the washing tub (3).
A non-limiting embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 shows an axonometric view, with parts in section and parts removed for clarity, of a front-loading home laundry washing and drying machine realized in accordance with the teachings of the present invention;
Figures 2, 3 and 11 show respective axonometric views of the rear portion of the washing group of the Figure 1 washing and drying machine with parts removed for clarity;
Figure 4 shows an enlarged axonometric view of the rear portion of the Figure 2 washing group with parts in section and parts removed for clarity;
Figures 5 and 6 show, respectively, the front view and the rear view of the cover forming part of the rear portion of the washing group already shown in Figure 2;
Figures 7 and 8 show, in enlarged scale and from different points of view, two details of rear portion of the washing group already shown in Figures 3 and 4, with parts removed for clarity; and
Figures 9, 10, 12 and 13 show the rear view and the later view of the washing group already shown in Figure 2, with parts in section and parts removed for clarity.

With reference to Figures 1, 2, 3 and 4, number 1 indicates as a whole a preferably, though not necessarily, household, front-loading laundry washing and drying machine which comprises:

a preferably, though not necessarily, substantially parallelepiped-shaped outer boxlike cabinet or casing 2 structured for resting on the floor;
a substantially cylindrical, bell-shaped washing tub 3 which is suspended in floating manner inside the casing in known manner via a number of coil springs 4 and shock-absorbers 5, with the bell mouth directly facing a laundry loading/unloading through opening realized in the front wall 2a of casing 2; and
a porthole door 6 which is hinged to the front wall 2a of casing 2 to rotate about a preferably, though not necessarily, vertical reference axis to and from a closing position in which door 6 rests on the front face of casing 2 to close the laundry loading/unloading on front wall 2a and watertight seal the mouth of washing tub 3.

In the example shown the washing tub 3 preferably, though not necessarily, extends inside the casing 2 coaxial to a substantially horizontally-oriented longitudinal reference axis L, and has the mouth directly faced to the laundry loading/unloading opening realized on front wall 2a; and the laundry washing and drying machine 1 is provided with a substantially cylindrical elastically-deformable bellows which connects in watertight manner the mouth of washing tub 3 to the laundry loading/unloading opening on front wall 2a of casing 2.
In addition to the above, the laundry washing and drying machine 1 also comprises, inside casing 2:

a substantially bell-shaped, cylindrical revolving drum (not shown) which is structured for housing the laundry to be washed and/or dried, and is housed in axially rotating manner inside the washing tub 3 for rotating about its longitudinal axis preferably, though not necessarily, coinciding with the longitudinal reference axis L of washing tub 3;
an electric motor assembly 7 which is preferably, though not necessarily, attached to the washing tub 3, outside the latter, and is structured for driving into rotation, on command, the revolving drum about its longitudinal axis, inside the washing tub 3; as alternative a direct drive motor fixed to the outer face of the rear wall 3b of the washing tub 3 can be envisaged.

a freshwater supply circuit 8 which is connected to the water mains or similar, and is structured for channeling into the washing tub 3, on command, the fresh water to be used in the washing cycle;
a washing-water recirculating and/or draining circuit 9 which is structured for sucking, on command, the washing water from the bottom of the washing tub 3 and feeding said water back inside the revolving drum, or alternatively draining the water accumulated on the bottom of washing tub 3 directly into a waste-water exhaust duct (non shown) located outside casing 2; and
an electrically-powered water heater 10, for example a resistor, which is located on the bottom of washing tub 3, preferably, thought not necessarily, into an outwards-projecting basin-shaped bulge formed on the lateral wall of washing tub 3, and is structured for rapidly heating the washing water accumulated on the bottom of washing tub 3.

With reference to Figures 1 and 2, laundry washing and drying machine 1 finally comprises a detergent dispenser 11 which is structured for supplying into washing tub 3 the detergents and/or softeners to be used in the washing cycle.
In the example shown detergent dispenser 11 preferably, though not necessarily, comprises a substantially parallelepiped-shaped container or receptacle 12 which is associated to the front wall 2a of casing 2, immediately above washing tub 3, so as to be directly accessible from an opening realized on front wall 2a, and is structured for housing in manually-extractable manner a detergent drawer (not shown) which, in turn, is provided with one or more compartments dimensioned for storing a given amount of detergent and/or softener to be used in the washing cycle.
The freshwater supply circuit 8 is structured for spilling, on command, the fresh/tap water of the water mains directly into the detergent drawer fitted into the container or receptacle 12, so as to flush on the bottom of the drawer container or receptacle 12 the detergents and/or softeners previously left into the detergent drawer; and the bottom of the drawer container or receptacle 12 communicates with the inside of washing tub 3 via a large delivering pipe 13 dimensioned to channel by gravity any kind of liquid into washing tub 3.
In other words, the delivering pipe 13 is structured for channeling into washing tub 3 the detergents and/or softeners to be used in the washing cycle together with all the fresh/tap water that the freshwater supply circuit 8 draws from the water mains and spills into the drawer container or receptacle 12 to perform the washing cycle.
The detergent dispenser 11, the freshwater supply circuit 8, and the washing-water recirculating and/or draining circuit 9 are commonly known parts in the laundry washing machines technical field, and therefore wont be described in further details.
Likewise most of currently-marketed laundry washing and drying machines, laundry washing and drying machine 1 is also provided with a closed-circuit, hot-air generator 14 which is structured to circulate inside washing tub 3, on command, a stream of hot air having a low moisture content, and which flows through the revolving drum and over the laundry stored inside the drum to rapidly dry the laundry.
The hot-air generator 14 is structured for gradually drawing air from the bottom of the washing tub 3; cooling down the air arriving from washing tub 3 so to extract and retain the surplus moisture in the air; heating the dehumidified air to a predetermined temperature, normally higher than the temperature of the air arriving from washing tub 3; and finally feeding the heated, dehumidified air back into washing tub 3, where it flows over the laundry located inside the revolving drum to rapidly dry said laundry.
With reference to Figures 1, 2 and 3, the hot-air generator 14 is, preferably, attached directly to the washing tub 3 and comprises:

an electrically-powered centrifugal fan 15 or other type of air circulating pump, which is, preferably, rigidly attached to the outer surface of washing tub 3, approximately on the top of the tub;
an air duct 16 which connects the delivery of the centrifugal fan 15 to the elastically-deformable bellows which connects the mouth of washing tub 3 to the laundry loading/unloading opening realized in front wall 2a, so as to channel the air arriving from centrifugal fan 15 back into washing tub 3 through the mouth of the latter;
an electrically-powered air heater (not shown), for example a resistor, which is located inside the air duct 16, and is structured for rapidly heating up the airflow directed towards washing tub 3 along air duct 16; and
a water cooled condenser (also indicated in the following as cold-water condenser) 17 which is located on the rear wall 3b of washing tub 3 with the inlet of the condenser in direct communication with the inside of washing tub 3, and the outlet of the condenser in direct communication with the suction of the centrifugal fan 15 so to oblige the centrifugal fan 15 to suck air from the washing tub 3 solely through the condenser 17, and which is structured so to use the freshwater of the water mains (cooling water) to which the freshwater supply circuit 8 is connected, for cooling down and dehumidifying the air that centrifugal fan 15 draws from the inside of washing tub 3.

Differently from today's laundry washing and drying machines, however the cold-water condenser 17 of the hot-air generator 14 is completely integrated in the rear wall 3b of washing tub 3, so as to form a one piece with the latter, and it is specifically structured so as to use the freshwater that the delivering pipe 13 channels into washing tub 3 as refrigerant for cooling down and dehumidifying the air that centrifugal fan 15 draws from washing tub 3.
With reference to Figures 2-6, the rear wall 3b of washing tub 3 is made of plastic material via a per-se known injection molding process, so as to have, on the outer face, a substantially C-shaped seat or recess 18 which extends close to the periphery of rear wall 3b, along an annulus sector preferably, though not necessarily, less than 120° wide; and a plenty of outwards-projecting reinforcing ribs 19 which are evenly distributed on the whole outer face of rear wall 3b, except for the annulus sector on the periphery of rear wall 3b where the C-shaped seat or recess 18 is located.
The lower end of the seat or recess 18 is in direct communication with the inside of washing tub 3 via a first through opening 18a located close to the bottom of washing tub 3; whereas the upper end of the seat or recess 18 is in communication with the suction of the centrifugal fan 15 via a second through opening 18b located approximately on the top of washing tub 3. Through openings 18a and 18b define, respectively, the inlet and the outlet of cold-water condenser 17.
In turn, the outwards-projecting reinforcing ribs 19 are preferably, though not necessarily, arranged on the outer face of rear wall 3b according to a substantially radially-oriented layout roughly centered to the longitudinal axis L of washing tub 3.
With reference to Figures 2-6, in addition to the above, washing tub 3 further comprises a substantially flat, C-shaped lid or cover 20 which is made of plastic material; is dimensioned so to completely cover the C-shaped seat or recess 18 on rear wall 3b; and is welded to the rear wall 3b of washing tub 3 via a vibration welding process, so to hermetically close the C-shaped seat or recess 18 and to form, together with the C-shaped seat or recess 18, a substantially C-shaped, huge internal main conduit 21 which extends inside the rear wall 3b of washing tub 3, close to the periphery of the latter, along an annulus sector preferably, though not necessarily, less than 120° wide. The C-shaped internal conduit 21 connects the suction of centrifugal fan 15 to the inside of washing tub 3.
Preferably, the lower end of internal conduit 21 is in direct communication with the inside of washing tub 3, close to the bottom of the latter; whereas the upper end of internal conduit 21 directly communicates with the suction of centrifugal fan 15, so that the stream of air directed towards the centrifugal fan 15 is obliged to flow along conduit 21, from the lower to the upper end of the latter.
In addition to the above, with reference to Figures 2-9, a midway section of internal conduit 21 is structured so as to be in direct communication with the delivering pipe 13 arriving from the drawer receptacle 12 of detergent dispenser 11, so that all tap water drawn from the water mains by the freshwater supply circuit 8 is channeled directly into the internal conduit 21 and it is obliged to flow by gravity towards the bottom of washing tub 3 through the lower length of internal conduit 21, counter-current to the airflow directed towards the suction of centrifugal fan 15.
When flowing along the lower length of internal conduit 21, the cold tap water arriving from delivering pipe 13 is allowed to cool down the airflow directed towards the outlet of internal conduit 21 where the centrifugal fun 15 is located, and to retain the condensed surplus moisture in said airflow.
In the example shown, in particular, in a midway section of the seat or recess 18 of rear wall 3b there is a third through opening 18c which communicates with the outside of washing tub 3, and the delivering pipe 13 is connected to the washing tub 3 so as to channel into said third through opening 18c all the tap water that the freshwater supply circuit 8 feeds into the drawer receptacle 12 of detergent dispenser 11.
With reference to Figures 2 and 5, the outer face of the lid or cover 20 is additionally provided with a plenty of outwards-projecting reinforcing ribs 20a which are arranged according to a substantially radially-oriented layout complementary to that of the outwards-projecting reinforcing ribs 19 on rear wall 3b, so as to cooperate, when cover 20 is rigidly welded to rear wall 3b, with the outwards-projecting reinforcing ribs 19 to stiffen the rear portion of washing tub 3.
With reference to Figures 2 and 4, moreover, the lid or cover 20 and, if present, its reinforcing ribs 20a do not protrude above the crest lines of the reinforcing ribs 19 on rear wall 3b. The applicant has found that positioning the lid or cover 20 below the crest lines of the reinforcing ribs 19 significantly increases the rigidity the rear wall 3b of washing tub 3.
In the example shown, the crest lines of the reinforcing ribs 20a on the outer face of the lid or cover 20 are preferably, though not necessarily, locally substantially aligned, i.e. coplanar, to the crest lines of the reinforcing ribs 19 on rear wall 3b of washing tub 3.
With reference to Figures 3-9, the cold-water condenser 17 is preferably, though not necessarily, also provided with an inwards-projecting spoiler 22 which protrudes from the inner surface of internal conduit 21 immediately downstream of the inlet of the latter, i.e. immediately above the through opening 18a, and is shaped so as to generate strong turbulences in the air flowing along the lower length of internal conduit 21 towards the upper outlet of internal conduit 21; and with an inwards-projecting water slide 23 which protrudes from the inner surface of internal conduit 21 immediately upstream of the midway section of internal conduit 21 communicating with the delivering pipe 13, i.e. immediately below the intermediate through opening 18c, and is shaped so as to force all the tap water arriving from delivering pipe 13 to form a waterfall which is located approximately in the centerline of internal conduit 21.
The water slide 23 is shaped so as to collect cooling water arriving from delivering pipe 13 and to channel said water roughly in the local center of the internal conduit 21, where cooling water is allowed to fall down the lower length of the internal conduit 21 while remaining approximately in the centerline of internal conduit 21 so to cross the maximum air-turbulence zone of the conduit.
The water slide 23 is shaped so as to prevent the cooling water channeled into internal conduit 21 from lapping/licking against the inner surface of conduit 21 while the water flows through the condenser 17 and to direct the water approximately in the centerline of internal conduit 21 so to cross the maximum air-turbulence zone of the conduit, thereby maximizing the heat exchange between the cooling water and the moisture laden hot air.
In other words, the water slide 23 is shaped so as to prevent the cooling water from contacting/flowing along the inner surface of conduit 21 and to convey the cooling water to a central portion of internal conduit 21, thus maximizing the heat exchange between the cooling water falling down along the internal conduit 21, and the hot air directed towards the outlet of internal conduit 21 where the centrifugal fun 15 is located.
Obviously, the condensed surplus moisture of the hot air flowing along the lower length of the internal conduit 21 is swept away by the tap water directed into the washing tub 3.
In the example shown, in particular, the inwards-projecting spoiler 22 is formed by two mutually faced and substantially coplanar winglets 22 protruding one from the bottom of the seat or recess 18 realized in the rear wall 3b of washing tub 3, and the other from the inner face of the lid or cover 20, and which extend one towards the other preferably, though not necessarily, so as to put the respective distal side edges in substantial abutment one against the other.
As an alternative, the inwards-projecting spoiler 22 may also consist in a single winglet which protrudes from the bottom of the seat or recess 18 realized in the rear wall 3b of washing tub 3, and extends towards the overhanging lid or cover 20 so as to put its distal side edge in substantial abutment against the inner face of the lid or cover 20.
With particular reference to Figures 4 and 6-9, the inwards-projecting water slide 23, in turn, is formed by two mutually faced and reciprocally inclined main winglets 24 and 25 which cantileverly protrude from, respectively, the bottom surface of the seat or recess 18 realized in the rear wall 3b of washing tub 3 and from the inner face of the lid or cover 20, and which extend one towards the other so as to put the respective distal side edges in abutment one against the other to form a substantially V-shaped channel which extends inside the internal conduit 21 approximately up to center of the local section of the internal conduit 21. The V-shaped channel therefore fills up the whole depth of the internal conduit 21.
In the example shown the inwards-projecting water slide 23 extends inside internal conduit 21 in a substantially radially-oriented direction, towards longitudinal axis L, and ends approximately at the center of the local section of internal conduit 21.
In addition to the above, the distal side edges of winglets 24 and 25 are mutually welded during the vibration welding process which hermetically welds the lid or cover 20 to the rear wall 3b of washing tub 3, so as to prevent the tap water arriving from delivering pipe 13 from leaking into the joint line between winglets 24 and 25.
Preferably, with reference to Figures 7, 8 and 9, for allowing the lid or cover 20 to freely vibrate on the rear wall 3b of washing tub 3 during the vibration welding process, in the example shown the end portion of winglet 25 extends inside the volume of seat or recess 18 of rear wall 3b, towards the distal side edge of winglet 24, remaining slightly spaced apart from the lateral surface of the seat or recess 18; and the water slide 23 additionally comprises an auxiliary transversal winglet 26 which cantileverly protrudes from the lateral surface of the seat or recess 18 of rear wall 3b, immediately above winglets 24 and 25, so as to cover like a penthouse the transversal slit 27 formed between the lateral edge of winglet 25 and the surface of the seat or recess 18 on rear wall 3b.
With reference to Figures 6, 7, 8 and 9, finally the cold-water condenser 17 is preferably, though not necessarily, provided with one or more low-profiled inwards-projecting transversal ribs 28 which are located in the upper length of the internal conduit 21, and protrude from the inner surface of internal conduit 21 - i.e. from the inner surface of the seat or recess 18 of rear wall 3b, or from the rear face of the lid or cover 20 -, so as to prevent the water droplets condensed on the inner surface of internal conduit 21 from flowing upwards upon the inner surface pushed by the airflow directed towards the suction of centrifugal fun 15, up to reach the upper outlet of the internal conduit 21.
General operation of the front-loading home laundry washing and drying machine 1 is clearly inferable from the above description, with no further explanation required.
The advantages connected to the particular location and structure of the cold-water condenser 17 are large in number. First of all, the complete integration of the cold-water condenser 17 of hot-air generator 14 into the rear wall 3b of washing tub 3 considerably reduces the total weight and the overall depth of the washing group floatingly suspended inside casing 2, thus allowing the use of a boxlike casing 2 having standard dimensions.
Furthermore, the cold-water condenser 17 now also serves as additional stiffening member of the rear wall 3b of washing tub 3, thus allowing a slightly reduction of the plastic material to be used in the injection molding process for realizing the substantially cup-shaped rear half-shell of washing tub 3, without any reduction in the washing-tub local structural stiffness.
Clearly, changes may be made to the laundry washing and drying machine 1 as described herein without, however, departing from the scope of the present invention.
For example, the air duct 16 may connect the delivery of centrifugal fan 15 directly to the washing tub 3, very close to the mouth of the revolving drum, so as to channel and direct the airflow arriving from the centrifugal fan 15 directly into the mouth of the revolving drum.

Claims

Laundry washing and drying machine (1) comprising an outer casing (2) structured for resting on the floor and, inside the casing (2):
- a washing tub (3) arranged inside the casing (2);

- a rotatable drum housed in axially rotating manner inside the washing tub (3) and structured for housing the laundry to be washed and/or dried; and

- a closed-circuit structured to circulate inside the washing tub (3) a stream of hot air, which flows through the rotatable drum and over the laundry stored inside the drum to dry said laundry;
the closed-circuit being provided with air circulating means (15) and with a water cooled condenser (17) fluidly communicating with the inside of the washing tub (3) and with the suction of the air circulating means (15); the laundry washing and drying machine (1) being characterized in that at least the rear wall (3b) of the washing tub (3) is made of plastic material, and it is provided with a seat or recess (18) which extends on the outer face of the rear wall (3b), and with a plurality of reinforcing ribs (19) which are distributed on the outer face of the rear wall (3b) of the washing tub (3), except for the area where the seat or recess (18) is located; the condenser (17) comprises an internal main conduit (21) delimited by the seat or recess (18) and by a lid or cover (20), the internal main conduit is structured so to use the freshwater of the water mains or similar water source as refrigerant for cooling down and dehumidifying the air that the air circulating means (15) draws from the washing tub (3).
Laundry washing and drying machine according to Claim 1, characterized in that the seat or recess (18) on the outer face of the rear wall (3b) of the washing tub (3) is a substantially C-shaped seat or recess (18) which extends close to the periphery of said rear wall (3b); and that the lid or cover (20) is a substantially flat, C-shaped lid or cover (20) which is dimensioned so to cover said C-shaped seat or recess (18) on the rear wall (3b) of the washing tub (3), and is coupled to the rear wall (3b) of washing tub (3) so to hermetically close said C-shaped seat or recess (18) for forming, together with the C-shaped seat or recess (18), a substantially C-shaped, internal main conduit (21) which, in turn, extends inside the rear wall (3b) of the washing tub (3) close to the periphery of the latter.
Laundry washing and drying machine according to Claims 1 or 2, characterized in that the internal main conduit (21) of the condenser (17) is fluidly connected to a delivering pipe (13) adapted to supply both the detergents and/or softeners and the freshwater to be used in the washing cycle and to be channeled into the washing tub (3) through the condenser (17), the delivering pipe (13) is adapted to supply the freshwater to be used in the drying cycle for cooling down and dehumidifying the air flowing through internal main conduit (21).
Laundry washing and drying machine according to any one of the foregoing claims, characterized in that the condenser (17) is also provided with an inwards-projecting water slide (23) which protrudes from the inner surface of the internal main conduit (21) immediately upstream of a section of the main conduit (21) which fluidly communicates with a delivering pipe (13), and is shaped so as to oblige the water arriving from the delivering pipe (13) to form a waterfall which is located approximately in the centerline of said main conduit (21).
Laundry washing and drying machine according to any one of the foregoing claims, characterized in that the lid or cover (20) does not protrude above the crest lines of the reinforcing ribs (19) on the rear wall (3b) of the washing tub (3).
Laundry washing and drying machine according to any one of the foregoing Claims, characterized in that the condenser (17) is also provided with an inwards-projecting spoiler (22) which protrudes from the inner surface of the internal main conduit (21) immediately downstream of an inlet (18a) of the latter, and is shaped so as to generate strong turbulences in the air flowing between the inlet of the condenser (17) and a section of the main conduit (21) fluidly communication with the delivering pipe (13).
Laundry washing and drying machine according to any one of the foregoing Claims, characterized in that the condenser (17) is also provided with one or more low-profiled inwards-projecting transversal ribs (28) which are located downstream of a section of the main conduit (21) fluidly communicating with the delivering pipe (13) and protrude from the inner surface of the internal main conduit (21) so as to prevent the water droplets condensed on the inner surface of said main conduit (21) from flowing upwards pushed by the airflow directed towards the suction of the air circulating means (15).
Laundry washing and drying machine according to any one of the foregoing Claims, characterized in that the outer face of the lid or cover (20) is additionally provided with a plurality of reinforcing ribs (20a) which are arranged so as to cooperate with the reinforcing ribs (19) on the rear wall (3b) of the washing tub (3) to stiffen the rear portion of the washing tub (3).
Laundry washing and drying machine according to Claim 4, characterized in that the inwards-projecting water slide (23) comprises two mutually faced and reciprocally inclined main winglets (24, 25) which protrude from, respectively, the bottom surface of the seat or recess (18) in the rear wall (3b) of the washing tub (3) and the inner face of the lid or cover (20), and which extend one towards the other so as to put the respective distal side edges in abutment one against the other for forming a substantially V-shaped channel which extends inside the internal main conduit (21) approximately up to the center of the local section of the main conduit (21).
Laundry washing and drying machine according to Claim 9, characterized in that the distal side edges of the two main winglets (24, 25) are mutually welded during the welding process that fixes the lid or cover (20) to the rear wall (3b) of the washing tub (3).
Laundry washing and drying machine according to Claim 10, characterized in that the inwards-projecting water slide (23) additionally comprises an auxiliary transversal winglet (26) which cantileverly protrudes from the surface of the seat or recess (18) realized on the outer face of the rear wall (3b) of the washing tub (3), immediately above the two main winglets (24, 25), so as to cover in penthouse-like manner a transversal slit (27) formed between the lateral edge of one (25) of the two main winglets (24, 25) and the surface of the seat or recess (18) on the rear wall (3b) of the washing tub (3).
Laundry washing and drying machine according to Claim 6, characterized in that said inwards-projecting spoiler (22) comprises at least a first winglet (22) which protrudes from the bottom of the seat or recess (18) realized in the rear wall (3b) of the washing tub (3), and extends towards the overhanging lid or cover (20) so as to put its distal side edge in substantial abutment against the inner face of said lid or cover (20), or against the distal side edge of a substantially coplanar second winglet (22) which protrudes from the inner face of said lid or cover (20).
Laundry washing and drying machine according to any one of the foregoing Claims, characterized in that the reinforcing ribs (19) are arranged on the outer face of the rear wall (3b) of the washing tub (3) according to a substantially radially-oriented layout roughly centered to the longitudinal axis (L) of the washing tub (3).
Laundry washing and drying machine according to Claim 3, characterized in that the laundry washing and drying machine (1) is provided with a detergent dispenser (11) comprising a container or receptacle (12) which is located inside the casing (2) and is structured for housing an extractable drawer which, in turn, is provided with one or more compartments dimensioned for storing a given amount of detergent and/or softener to be used in the washing cycle; the bottom of said container or receptacle (12) communicating with the inside of the washing tub (3) via said delivering pipe (13).
Laundry washing and drying machine according to any one of the foregoing claims, characterized in that the washing tub (3) has the mouth directly faced to a laundry loading/unloading opening realized in the front wall (2a) of the casing (2); and in that the laundry washing and drying machine (1) is also provided with a bellows which connects in watertight manner the mouth of the washing tub (3) to the laundry loading/unloading opening on the front wall (2a) of the casing (2).