EP2019160B1

EP2019160B1 - Washer-drier machine

Info

Publication number: EP2019160B1
Application number: EP07425474A
Authority: EP
Inventors: Silvano Fumagalli
Original assignee: Candy SpA
Current assignee: Candy SpA
Priority date: 2007-07-26
Filing date: 2007-07-26
Publication date: 2010-09-22
Anticipated expiration: 2027-07-26
Also published as: EP2019160A1; DE602007009374D1

Description

The present invention relates to a domestic washer-drier machine which provides for washing and drying the laundry.
Domestic washer-drier machines are known to comprise a support and housing structure, a washing tank being housed therein, which is provided with a front opening that can be closed by means of a porthole door that is hinged in front of the housing. Within the washing tank, a basket is pivotally housed about a horizontal or inclined axis for the laundry to be accommodated therein to be washed and/or dried. The basket also defines a front opening that is located such as to match the opening of the washing tank, in order to load/unload the laundry.
The washing tank is suitable to contain the washing liquid during the laundry washing steps, and to be a portion of the drying circuit during the laundry drying step.
In order to allow loading the tank with mains water and detergent and additive substances, a washing water delivery system is provided to be connected to the water system. This washing water delivery system comprises a plurality of electrovalves which are suitable to selectively adjust the supply to a plurality of flow paths extending downstream of these electrovalves through respective compartments of a detergent tray to the washing tank. On the bottom of the washing tank there is provided a drain duct with a discharge pump being associated thereto, which provides for the removal of the washing liquid from the tank and controls, together with the supply electrovalves, the liquid level within the tank. To heat the washing liquid contained within the tank, an electric resistance is provided, which is arranged within the tank in the gap between the tank wall and the laundry basket.
A drying circuit of prior art washer-drier machines, see e.g. JP 2005 224 621 A , typically comprises a suction unit, a heat exchanger and a heating unit with electric resistances intercommunicating by means of a drying circuit.
In such a closed-loop circuit, the air flow generated by the suction unit is heated by the electric resistances and sent to the basket, where it flows through the wet laundry thereby causing the water contained in the fabric to evaporate. In the heat exchanger, which is generally a container separate from the washing tank and provided with a spray nozzle, the wet air is cooled by a jet of cold water. Due to this cooling, the vapour condensates and is collected and discharged together with the cooling water. The de-humidified air is then sucked again by the suction unit and ricirculated.
The cooling water is usually supplied to the heat exchanger by means of a cooling duct with a dedicated electrovalve which controls the loading of the mains water in the heat exchanger (condenser).
Prior art drying devices, while being satisfactory under many aspects, however, have a much complicated structure which is due to the presence of the condensation chamber and three different circuits:

washing water supply,
cooling water supply to the heat exchanger,
drying air circuit,

The structural complexity of known washer-drier machines and the high consumption of cooling water during the drying step are some of the causes of the high production and running costs that are related to this type of appliance.
The production cost of the washer-drier machines result to be further increased by the difficulty or impossibility of using the large-scale components that are manufactured for washing machines.
US 3,012,333 A , EP 1,500739 A and EP 1,314,809 A disclose washer-drier machines having the features of the pre-ample of claim 1
Therefore, the object of the present invention is to provide a washer-drier machine having such characteristics as to overcome at least some of the problems mentioned with reference to the prior art.
This and other objects are achieved by means of a washer-drier machine according to claim 1. Advantageous embodiments are the object of the dependent claims.
According to the invention, the washer-drier machine comprises:

a laundry basket being supported within a washing tank suitable to contain the washing liquid;
a drying circuit comprising a tubular suction duct,

the suction duct is formed of a wall portion of the washing tank and a lid, which is manufactured separately and then connected to the wall portion.

According to one aspect of the invention, the lid comprises a system of cavities that are suitable to contain the cooling water, namely a cooling coil that can be supplied with mains water such that the lid forms a condensation wall.
As the suction duct is formed by the tank wall and by a lid that is manufactured separately and then connected to the tank wall, the same washing tank (with and without lid, respectively) can be used both for manufacturing washing machines and for manufacturing washer-drier machines.
Furthermore, by providing the lid with a system of cavities to contain the cooling water, the traditional atmospheric condenser separated from the tank can be eliminated and the overall structure of the washer-drier machine can be simplified.
Since the cooling water volume is maintained within the lid coil, a continuous use of a same water volume will be allowed until the latter reaches an upper threshold temperature for condensation purposes. This results in a considerable saving of cooling water during the drying step.
In accordance with a further embodiment of the invention, the system of cavities, i.e. the lid cooling coil, is arranged in the washing water supply path, preferably in series between the supply electrovalve and a detergent tray and can be supplied by means of the same washing water supply circuit.
This allows the elimination of a dedicated supply circuit for supplying the condenser as well as a simplification of the control programs driving the supply electrovalves.
In order to better understand the invention and appreciate the advantages thereof, several embodiments thereof will be described below by way of non-limiting examples, with reference to the annexed drawings, in which:

Fig. 1 is a side sectional view of a washer-drier machine ;
Fig. 2 is a front sectional view of the washer-drier machine in Fig. 1;
Fig. 3 is a side sectional view of washer-drier machine according to an embodiment of the invention;
Fig. 4 is a front sectional view of the washer-drier machine in Fig. 3;
Fig. 5 is a partially sectional top view of the washer-drier machine in Fig. 3;

With reference to the figures, a washer-drier machine 1 comprises a support and housing structure 2, a washing tank 3 being housed therein, which is provided with a front opening that can be closed by means of a porthole door 4 being hinged in the front of the housing 2. Within the washing tank 3, a basket 5 is pivotally housed about a horizontal or inclined axis, for the laundry to be accommodated therein to be washed and/or dried. The basket 5 also defines a front opening that is located such as to match the opening of the washing tank 3, in order to load/unload the laundry.
The washing tank 3 is suitable to contain the washing liquid during the laundry washing steps, and to be a portion of the drying circuit during the laundry drying step.
In order to allow loading the tank 3 with mains water and detergent and additive substances, a washing water delivery system is provided to be connected to the water system. This washing water delivery system comprises a plurality of washing flow paths extending from, for example, two supply electrovalves 6, 7, through corresponding compartments 8, 9, 10 of a detergent tray 12, to the washing tank 3.
On the bottom 13 of the washing tank 3, there is provided a drain duct 14 with a discharge pump 15 being associated thereto, which provides for the removal of the washing liquid from the tank 3 and controls, together with the supply electrovalves 6, 7 the level of liquid within the tank 3.
To heat the washing liquid contained within the tank 3, a coiled electric resistance 11 is provided, which is arranged within the tank 3, particularly on the bottom 13 of the latter, in the gap between the tank wall 3 and the laundry basket 5.
The washer-drier machine 1 further comprises a closed-loop drying circuit with a suction unit, for example an fan impeller 17 driven by an electric motor 18, a heat exchanger as well as a heating unit with electric resistance 21, which communicate with each other by means of a drying circuit 16.
In such a closed-loop circuit, the air flow 22 generated by the suction unit 17, 18 is heated by the electric resistance 21 and sent to the basket 5, where it flows through the wet laundry thereby causing the water contained in the fabric to evaporate. The heat exchanger is arranged downstream of the laundry basket 5 (with reference to the direction of the drying air flow 22) and cools the wet air flowing from the basket 5.
Due to this cooling, the vapour condensates and is collected and discharged, for example together with a volume of cooling water. The de-humidified air is then sucked again by the suction unit 17, 18 and ricirculated.
According to one aspect of the invention, the drying circuit 16 comprises a tubular suction duct 26 formed of a wall portion 27 of the washing tank 3 and of a lid 28 that is manufactured separately and then connected to the wall portion 27.
The lid 28 comprises a system of cavities that are suitable to contain the cooling water, namely a cooling coil 29 that can be supplied with mains water such that the lid 28 forms a condensation wall.
Thereby, the atmospheric condenser separated from the tank can be eliminated and the overall structure of the washer-drier machine can be simplified. Furthermore, since a cooling water volume is maintained within the coil 29 of the lid 28, a continuous use of a same water volume will be allowed until the latter reaches an upper threshold temperature for condensation purposes. This results in a considerable saving of cooling water during the drying step.
In accordance with an embodiment, this suction duct 26 extends within the washing tank 3 from a lower area thereof to an opening 30 in the upper area thereof and is defined by a portion of the inner surface of the tank 3 and by the lid 28.
Thereby, the same washing tank 3 can be advantageously used both with washing machines without drying function (without the inner lid 28), and with drier-washer machines (with the inner lid 28). Furthermore, as the lid 28 forms a condensation wall, two condensation surfaces are obtained, i.e. the inner surface 31 and the outer surface 32 of the lid 28, which are both arranged within the washing tank 3 and blown by the drying air 22.
In accordance with an embodiment, the cooling coil 29 can be supplied with mains water and arranged in the washing water supply path, between the supply electrovalve 6, 7 and the washing tank 3, preferably upstream of the detergent tray 12.
Thereby, the cooling coil 29 is supplied by means of the same washing water supply circuit. This allows the elimination of a dedicated supply circuit for supplying the cooling coil 29 as well as a simplification of the control programs driving the supply electrovalves.
According to an advantageous embodiment, the lid 28 is made from plastics and the cooling coil 29 is formed by means of blow moulding at or in the lid 28. The lid 28 made of plastics can be used both with a metal washing tank (e.g. stainless steel) and with a washing tank made of plastics by means of moulding.
In accordance with an embodiment providing for a direct hydraulic connection with one of the supply valves 6, 7, the cooling coil 29 cannot be emptied. By opening the supply valve 6, 7, the water contained within the cooling coil 30 can be only replaced with fresh mains water.
Advantageously, the lid 28 is removably connected to the washing tank 3, such as to allow the same to be replaced in the event of damage, for example limestone clogging.
According to a further embodiment, the washing tank 3 defines therein and upstream of the suction duct 26 (with reference to the direction of the drying air flow 22) a condensation space 19 that is suitable to contain a volume of cooling water 20 that forms a surface of free water and spaced away from the basket 5 such as to be capable of cooling the drying air flow 22 downstream of the basket 5 and upstream of the suction duct 26 within the washing tank 3.
As the lid 28 comprises the cooling coil 29, the free water surface is an additional condensation surface to those provided by the lid 28.
According to an embodiment, the condensation space 19 is formed at the tank bottom 13, approximatively below the basket 5.
This further condensation surface also does not require any dedicated supply circuit, because the water volume 20 (condensation surface) on the bottom of the washing tank 3 can be easily supplied with the mains water that is loaded by means of the washing water loading circuit.
Furthermore, the volume of cooling water 20 on the tank bottom 13 also allows a continuous use of a same water volume until the latter is heated past a threshold temperature allowed for condensation purposes. This results in a considerable saving of cooling water during the drying step.
The washer-drier machine 1 comprises a control unit (not shown in the drawings) that is configured such as to cause the discharge pump 15 and supply electrovalves 6, 7 to drain and/or replace the cooling water within the coil 29 of the lid 28 and/or the cooling water volume 20 on the tank bottom as a function of the temperature of the cooling water and/or as a function of the level of the mixture of cooling water 20 and condensate on the tank bottom 13. To the purpose, the control unit interacts with suitable pressure or level sensors 24 that are arranged at the tank bottom 13 and one or more temperature sensors 25 that are arranged in direct or indirect thermal contact with the cooling water within the lid 28 and/or on the tank bottom 13.
Alternatively, the control unit is configured such as to cause the discharge pump 15 and supply electrovalves 6, 7 to drain and/or replace the cooling water within the coil 29 of the lid 28 and/or the cooling water volume 20 on the tank bottom at predetermined time intervals, such that:

during the drying step, the temperature of the cooling water does not exceed an upper threshold temperature to the purposes of condensation and/or
during the drying step, the water level on the tank bottom 13 does not exceed an upper threshold level which will be set such that the basket 5 does not come in contact with the cooling water.

With reference to the embodiments providing a second heat exchanger, in addition to the cooling coil 29 being formed in the lid 28 (first heat exchanger), which consists of the cooling water volume 20 on the bottom of the washing tank 3, the control unit is preferably configured such as to allow selecting a drying program, in which, during an early drying step, only the first heat exchanger will be operated, whereas the condensation space 19 on the tank bottom 13 will be not provided with cooling water 20.
Thereby, during the early drying step, a drier environment is obtained within the tank, which is thus even more favourable to the extraction and condensation of the initial high amount of humidity contained in the laundry.
The washer-drier machine according to the invention has a number of advantages.
The suction duct being formed by the wall portion of the washing tank 3, and the lid 28 being manufactured separately and then connected to the wall portion, the same tank structure can be used both for washing machines and washer-drier machines.
The supply of the cooling water being carried out through the same ducts that are provided for carrying the washing water during the washing and rinse steps, a dedicated duct for supplying the heat exchanger is eliminated. This results in the elimination of at least one dedicated electrovalve for the heat exchanger and the spray nozzles and cooling ducts thereof.
By integrating the cooling coil in the lid 28, the space within the washer-drier machine can be better exploited, and both the structure and washing/drying programs are considerably simplified and unified.
Obviously, to the washer-drier machine according to the present invention, those skilled in the art, aiming at meeting contingent and specific requirements, may carry out a number of modifications and variations, all being however contemplated within the scope of protection of the invention, namely as defined in the annexed claims.

Claims

A washer-drier machine (1) for washing and drying the laundry comprising:
- a washing tank (3) suitable to contain the washing liquid;

- a basket (5) suitable to accommodate the laundry and pivotally supported within the washing tank (3);

- a drying circuit (16) with a suction unit (17, 18), a heat exchanger (19, 20) and a heating unit (21) which communicate with each other by means of a drying duct, said drying duct being suitable for delivering a drying air flow (22) through said basket (5),
wherein said drying circuit (16) comprises
a tubular suction duct (26) formed of a wall portion (27) of
the washing tank (3) and of a lid (28) that is manufactured separately and then connected to said wall portion, characterized in that the lid (28) comprises a cooling coil (29) that can be supplied with mains water, such that the lid (28) provides a condensation wall.
The washer-drier machine (1) according to claim 1, wherein said suction duct (26) extends within the washing tank (3) from a lower area thereof to an opening (30) in the upper area thereof and is defined by a portion of the inner surface of the tank (3) and by said lid (28).
The washer-drier machine (1) according to claim 1, wherein said condensation wall of said lid (28) provides two condensation surfaces (31, 32), which are both arranged within the washing tank (3) to be capable of being blown by the drying air (22).
The washer-drier machine (1) according to one of claims 1 or 3, wherein said cooling coil (29) of the lid (28) is arranged in the washing water supply path, between a supply electrovalve (6, 7) and the washing tank (3) and can be supplied by means of the same washing water supply circuit.
The washer-drier machine (1) according to the preceding claim, wherein said cooling coil (29) of the lid (28) is arranged upstream of a detergent tray (12).
The washer-drier machine (1) according to any preceding claim, wherein the lid (28) is made of plastics and the cooling coil (29) is formed by means of blow moulding at or in the lid (28).
The washer-drier machine (1) according to any preceding claim, wherein the lid (28) is removably connected to the washing tank (3), such as to allow being replaced.
The washer-drier machine (1) according to any preceding claim, wherein the washing tank (3) defines therein and upstream of the suction duct (26) with reference to the direction of the drying air flow (22) a condensation space (19) which is suitable to contain a volume of cooling water (20) that forms a free water surface spaced away from the basket (5) such as to be capable of cooling the drying air flow (22) downstream of the basket (5) and upstream of the suction duct (26) within the washing tank (3).
The washer-drier machine (1) according to any preceding claim, comprising a control unit that is configured such as to cause a discharge pump (15) and supply electrovalves (6, 7) to replace the cooling water within the coil (29) of the lid (28) as a function of the temperature of the cooling water.
The washer-drier machine (1) according to the preceding claim, wherein the control unit is configured such as to cause the discharge pump (15) and supply electrovalves (6, 7) to drain the cooling water volume (20) on the tank bottom (13) as a function of the temperature and level of the mixture of cooling water (20) and condensate on the tank bottom (13).
The washer-drier machine (1) according to claim 9 or 10, wherein the control unit interacts with a pressure sensor (24) that is arranged proximate to the tank bottom (13) and one or more temperature sensors (25) that are arranged in thermal contact, either directly or indirectly, with the cooling water in the lid (28) and/or on the tank bottom (13).
The washer-drier machine (1) according to claim 9 or 10, wherein the control unit is configured such as to cause the discharge pump (15) and supply electrovalves (6, 7) to drain and/or replace the cooling water at predetermined time intervals, such that:
- during the drying step, the temperature of the cooling water does not exceed an upper threshold temperature to the purposes of condensation and/or

- during the drying step, the water level on the tank bottom (13) does not exceed an upper threshold level set below the basket (5).