Method for refreshing laundry without additional hardware

Abstract

The present invention relates to a method for refreshing laundry (200) inside a drum (110) of a household appliance (100), wherein at least one heat source (11) for heating process air is heated to a defined temperature, wherein water is applied to the at least one heated heat source (11) directly or indirectly in order to at least increase humidity of process air inside a process air channel (120), and wherein the process air is moved inside the process air channel (120) from the heat source (11) to the drum (110) by controlling a process air fan (13). Furthermore, the invention relates to a household appliance.

Description

[0001] The present invention relates to a method for refreshing laundry inside a drum of a household appliance and to a household appliance.

[0002] Refreshing of laundry in a tumble dryer usually takes place by introducing moisture to laundry inside the drum and then drying the laundry. After such treatment, previously worn cloths regain freshness, since possible body odours may be partially removed. Moreover, by performing such refreshing procedure the aromatic scents from laundry detergents used in washing process are also easier traceable. An additional feature is partial removal of creasing of laundry items during such a procedure.

[0003] Regularly, the moisture is introduced in form of a hot steam by a separate steam generator or in form of a spray of cold water. Such solutions require additional hardware installed in the tumble dryer in order to fulfil functionality of first collecting water from a container, transforming it into steam or spray and delivering it to the laundry inside the drum. Additional hardware is more expensive to implement such that the overall dryer manufacturing costs are usually increased. Furthermore, the complexity of the appliance is increased by additional hardware which requires separate controls.

[0004] It is therefore an object of the present invention to provide a method and a household appliance which may enable a low-cost technical solution for a cloth refreshing functionality.

[0005] This problem is solved by a method according to claim 1 and by a household appliance according to the features of claim 10. Advantageous embodiments are set out in the dependent claims.

[0006] According to one aspect of the present invention, a method for refreshing laundry inside a drum of a household appliance is provided. In a method step at least one heat source for heating process air is heated to a defined temperature. Such defined temperature may be set in advance in order to evaporate water or in order to vaporize the water. The temperature of the heat source may be set for example to 70°C.

[0007] In a further method step water is applied to the at least one heated heat source directly or indirectly in order to at least increase humidity of process air inside a process air channel. Based on the appliance, the water can be applied to the heat source before reaching the defined temperature level and / or after reaching the defined temperature level.

[0008] The process air is moved inside the process air channel from the heat source to the drum by controlling a process air fan. Thus, a controller may activate and / or regulate the process air fan in order to move the humidity enriched process air into the drum and to the laundry inside the drum. The process air fan may be active the entire time or after at least some of the water evaporated into the process air channel.

[0009] Normally in a household appliance e.g. formed as a tumble dryer, the heat source is formed as a condenser and is used to reheat the dry air before it is directed to the drum. During this operation, the temperature on fins of the heat source reaches for example 70°C. The time until this temperature level is reached may be reduced if airflow in the process air channel of the appliance is not generated at least during some time period.

[0010] Depending on the application, the process air fan can run with a low RPM and by activating the process air fan, the RPM can be set to a higher level in order to provide a movement of the process air with higher velocity.

[0011] Based in a further aspect of the invention, a household appliance is provided. The inventive appliance is configured to perform the inventive method. The household appliance may in particular be a laundry-care appliance, in particular a tumble dryer or a washer-drier, i.e. a combined washing machine and tumble dryer. The appliance may comprise a drum for incorporating laundry and a process air channel. The process air channel connects at least a heat source with the drum and forms a circuit. At least one process air fan may be utilized in order to move the process air inside the process air channel.

[0012] Depending on the appliance, in movement direction of the process air, prior to the heat source a cold source may be arranged in order to condensate moisture, which is drawn from the laundry. Then, the cooled process air can be provided to the heat source in order to heat the process air and to guide the heated process air into the drum. Such heat source can be formed as a heat exchanger of a condenser of a heat pump. The cold source may be formed as an evaporator of the heat pump.

[0013] The condenser is configured to condense a coolant fluid in order to produce heat which may be utilized for heating process air and for evaporating water for the refreshing the laundry.

[0014] The evaporator may be utilized to evaporate the coolant of the heat pump thus extracting heat from the process air.

[0015] By providing the method additional hardware may be omitted, since the existing heat source of the appliance may be utilized for generating high humidity process air for refreshing the laundry. Thus, costs and complexity of the appliance, especially in form of a tumble dryer or in form of a washer dryer, may be reduced.

[0016] According to an embodiment, the water is applied to the at least one heated heat source by an integrated device for cleaning the heat source and / or the water is applied to at least one cold source of the appliance by an integrated device for cleaning the cold source. If the appliance is equipped with a condenser flushing functionality, the inventive method for refreshing laundry can be performed with minimized costs and reduced modification effort. Thus, the self-cleaning system of a condenser and / or evaporator as heat source and cold source may be utilized in order to apply water for increasing the humidity of the process air.

[0017] Based on a further embodiment, the heat source is formed as a condenser. The water may be spilled or sprayed on the frontal surface and / or on the inside of the as condenser formed heat source. Same procedure may also be applied to the at least one cold source. Moreover, in a further embodiment, the cold source is formed as an evaporator, wherein the condenser is positioned in direction of a flow of the process air behind the evaporator inside the process air channel, wherein the water is applied directly or indirectly to the condenser and to the evaporator. Thus, a heat pump configuration of a household appliance may be used for refreshing the laundry positioned inside the drum.

[0018] In a further embodiment, the water is applied to the process air prior to arriving at the heat source such that the water is applied indirectly to the heat source and / or cold source. Thus, the airflow inside the process air channel may carry the water spray or mist into the heat source. This measure enables the arrangement of a nozzle or of a diffusor spaced apart from the heat source providing higher degree of design freedom. Moreover, the amount of water carried to the heat source by airflow can be controlled by changing value of airflow, e.g. by controlling rotational velocity of process air fan. Thus, the humidity level inside the process air channel may be configured precisely, too.

[0019] Based on a further embodiment, the water is applied to the heat source and / or cold source by at least one spray nozzle or at least one diffusor. This measure allows a precise distribution of water along a surface area of the heat source and / or cold source.

[0020] In a further embodiment, the water is applied to the heat source and / or cold source by guiding water into the process air channel such that the heat source and / or cold are at least partially immersed in water. Thus, the heat source and / or cold may directly provide heat transfer with the water and increase the humidity of the process air by evaporation or vaporization. Such measure may be realized in a technically simplified manner.

[0021] In a further embodiment, an amount of water applied to the heat source and / or cold source is controlled by controlling a speed of a pump of the appliance and / or by controlling an aperture of at least one valve of the appliance. This measure allows a precise control of the applied water amount. Thus, the humidity level inside the process air channel may be configured precisely, too.

[0022] Based on a further embodiment, the water is drawn from a water tank of the appliance or from a water source connected to the appliance. Thus, flexible water management for refreshing laundry can be provided. After a refreshing of the laundry, which may be performed as a program of the appliance, the laundry is dried again. The water may be condensed in such a case and collected inside the water tank or drained from the appliance. This embodiment is especially important in a washer-drier.

[0023] In a further embodiment, the water is applied to one of multiple heat sources and / or cold sources at a time; or wherein the water is applied to all of multiple heat sources and / or cold sources simultaneously. Thus, even with a limited amount of water and / or with reduced energy consumption, the refreshing of laundry can be efficiently performed. Moreover, since the application of water reduces the surface temperature of a heat source, the application of water to different heat sources may be applied in an alternating manner. Thus, after applying water to one first heat source for a short period of time, the water may be applied to at least one further heat source allowing the temperature of the first heat source rise again. Thus, the efficiency and / or the speed of laundry refreshing may be increased.

[0024] The advantages and features explained above in connection with the method also apply analogously to the household appliance and vice versa. Individual features or aspects of the present invention can be combined with each other and have the advantages explained in this context.

[0025] In the following, the invention is explained in detail by means of advantageous embodiments with reference to the attached figure. Fig. 1a schematic view of a household appliance illustrating a method for refreshing laundry according to one embodiment.

[0026] In the figure, identical or corresponding elements are labelled with the same reference signs. Values and characteristics such as numerical values, shapes, components, positions of components and the way in which the components are connected to each other are merely illustrative and not restrictive. For reasons of clarity and to improve recognisability, different scales are sometimes used in the drawings.

[0027] Fig. 1 shows a schematic view of a household appliance 100 illustrating a method for refreshing laundry 200 according to one embodiment. The appliance 100 is formed as a tumble dryer in the shown example and is configured to perform the method for refreshing laundry 200 inside a drum 110 of the appliance 100.

[0028] The appliance 100 comprises a process air channel 120 beside the drum 110. The process air channel 120 connects at least one heat source 11 with the drum 110 and forms a circuit. In the shown example, the process air channel 120 also connects a cold source 12 with the drum 110 and the heat source 11.

[0029] At least one process air fan 13 may be utilized in order to move the process air inside the process air channel 120.

[0030] In movement direction of the process air inside the air channel 120, which is indicated by the arrows, the heat source 11 is arranged after the cold source 12. In order to perform drying of the laundry 200 inside the drum 110, the heat source 11 is heated. Thus, the process air is also heated and transferred via the process air channel 120 into the drum 110. The heated process air may incorporate moisture from the laundry 200. By running the process air fan 13 the humid process air is transported out of the drum 110 to the cold source 12 which cools the humid process air resulting in condensation of the humidity and in drying of the process air. After drying the process air it is heated by the heat source 11 again and fed into the drum 110.

[0031] In the shown example, the heat source 11 is formed as a heat exchanger of a condenser of a heat pump. The cold source 12 is formed as an evaporator of the heat pump of the appliance 100.

[0032] The condenser 11 is configured to condense a coolant fluid in order to produce heat which may be utilized for heating process air and for evaporating water for the refreshing the laundry 200.

[0033] The evaporator 12 is configured to evaporate the coolant of the heat pump, thus extracting heat from the process air.

[0034] The appliance 100 comprises a self-cleaning system of the condenser 11 and / or evaporator 12. Such system comprises at least one water outlet 21, 22 in order to apply water to the condenser 11 and / or evaporator 12. This feature allows removing lint and other contamination from the surfaces of the heat exchangers of the condenser 11 and / or evaporator 12.

[0035] The appliance 100 comprises a water tank 130 arranged in a base module of the appliance 100 which can be filled automatically or manually in order to perform the self-cleaning procedure. Inside the water tank 130 a water pump 140 is positioned. The water pump 140 is configured to pump water out of the water tank 130 to the water outlets 21, 22.

[0036] In the shown example, the water outlets 21, 22 are positioned above the heat exchangers of the condenser 11 and evaporator 12. This self-cleaning system is utilized by the inventive method for performing a laundry 200 refreshing procedure. The water outlets 21, 22 are formed as diffusors in order to provide a uniform coverage of the condenser 11 and evaporator 12 with water.

[0037] The amount of sprayed water can be configured by controlling the water pump 140. The water pump 140 can be designed as a BLDC Pump with the possibility to adjust the RPM precisely.

[0038] In order to use the self-cleaning system for refreshing the laundry 200, the following steps are performed: In a method step the heat source 12 for heating process air is heated to a defined temperature. The heat source 12 may be heated to an exemplary temperature of 70°C.

[0039] In a further method step the water is applied to the at least one heated heat source 11 directly or indirectly in order to at least increase humidity of process air inside a process air channel 120. The cold source 12 can also be provided with water in order to increase the overall humidity level inside the process air channel 120. The water is applied via the water outlets 21, 22 described above. The water is applied to the heat source 11 and cold source 12 after reaching the defined temperature level.

[0040] Whilst the condenser 11 is kept hot, the evaporator 12 gets cold. If the water was rinsed on the condenser 11 in order to increase humidity, the humid air would pass through laundry 200 only once before the humidity would be condensed on the evaporator 12. In order to prevent this from happening and keep the humidity in the process air also after passing through the evaporator 12, the evaporator 12 is at least occasionally rinsed with water during the process.

[0041] The process air is moved inside the process air channel 120 from the heat source 11 and the cold source 12 to the drum 110 by controlling the process air fan 13. Thus, a not shown controller may activate and / or regulate the process air fan 13 in order to move the humidity enriched process air into the drum 110 and to the laundry 200 inside the drum 110.

[0042] The contact of the warm humid process air with laundry 200 results in refreshing the laundry 200. At the end of the refreshing procedure the moisture is condensed and the laundry 200 is re-dried.List of reference signs

[0043] 100 -appliance 110 -drum 120 -process air channel 130 -water tank 140 -water pump 11 -heat source / condenser 12 -cold source / evaporator 13 -process air fan 21 -water outlet of condenser 22 -water outlet of evaporator

Claims

1. Method for refreshing laundry (200) inside a drum (110) of a household appliance (100), wherein at least one heat source (11) for heating process air is heated to a defined temperature, wherein water is applied to the at least one heated heat source (11) directly or indirectly in order to at least increase humidity of process air inside a process air channel (120), and wherein the process air is moved inside the process air channel (120) from the heat source (11) to the drum (110) by controlling a process air fan (13).

2. Method of claim 1, wherein the water is applied to the at least one heated heat source (11) by an integrated device for cleaning the heat source (11) and / or the water is applied to at least one cold source (12) of the appliance (100) by an integrated device for cleaning the cold source (12).

3. Method of claim 1 or 2, wherein the heat source (11) is formed as a condenser, and wherein the cold source (12) is formed as an evaporator, wherein the condenser is positioned in direction of a flow of the process air behind the evaporator inside the process air channel (120), wherein the water is applied directly or indirectly to the condenser and to the evaporator.

4. Method of any one of the claims 1 to 3, wherein the water is applied to the process air prior to arriving at the heat source (11) such that the water is applied indirectly to the heat source (11) and / or cold source (12).

5. Method of any one of the claims 1 to 4, wherein the water is applied to the heat source (11) and / or cold source (12) by at least one water outlet (21, 22) formed as a spray nozzle or as a diffusor.

6. Method of any one of the claims 1 to 5, wherein the water is applied to the heat source (11) and / or cold source (12) by guiding water into the process air channel (120) such that the heat source (11) and / or cold source (12) are at least partially immersed in water.

7. Method of any one of the claims 1 to 6, wherein an amount of water applied to the heat source (11) and / or cold source (12) is controlled by controlling a speed of a pump (140) of the appliance and / or by controlling an aperture of at least one valve of the appliance (100).

8. Method of any one of the claims 1 to 7, wherein the water is drawn from a water tank (130) of the appliance (100) or from a water source connected to the appliance (100).

9. Method of any one of the claims 1 to 8, wherein the water is applied to one of multiple heat sources (11) and / or to one of multiple cold sources (12) at a time; or wherein the water is applied to all of multiple heat sources (11) and / or cold sources (12) simultaneously.

10. Household appliance (100), configured to perform a method of any one of the claims 1 to 9.

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