WO2018162081A1

WO2018162081A1 - A method of operating a laundry dryer having a lint filter

Info

Publication number: WO2018162081A1
Application number: PCT/EP2017/055696
Authority: WO
Inventors: Hafize OZKILINC; Onur ERCAN; Erdem Kara; Mert GUNEY; Mustafa CENGIZ
Original assignee: Arcelik AS
Current assignee: Arcelik AS
Priority date: 2017-03-10
Filing date: 2017-03-10
Publication date: 2018-09-13
Anticipated expiration: 2019-09-10
Also published as: TR201802915A2

Abstract

A method of operating a laundry dryer (1) having a laundry treatment chamber (3) wherein the laundry to be dried is placed, an air circulation duct (4) connected to the laundry treatment chamber (3) for recirculating the process air (PA) used to dry the laundry placed in the treatment chamber (3), a cycle fan (5) which is located in the circulation duct (4) and provides the circulation of the process air (PA) and a filter (6) arranged in the air circulation duct (4) to collect lint/fluff carried by the process air (PA), the method comprising a step of rinsing the filter (6) with a washing liquid in order to remove the lint/fluff trapped on it.

Description

A METHOD OF OPERATING A LAUNDRY DRYER HAVING A LINT FILTER

The present invention relates to a method of operating a laundry dryer comprising a filter that holds the lint and fluff particles dragged by the drying air.

Closed cycle laundry dryers generally comprise a laundry treatment chamber wherein the laundry to be dried is placed, for instance in a drum arranged in it, and an air circulation duct connected to the laundry treatment chamber for recirculating and recycling the air used to dry the damp laundry in the treatment chamber removing the moisture from it. More in detail, before being reintroduced in the treatment chamber, the exhaust air exiting the treatment chamber is cooled and the water vapor contained in it is removed by condensation and the dried air is subsequently heated and fed back into the treatment chamber with low relative humidity rate and at high temperature.

To this aim the laundry dryers available in the market generally comprise, arranged on the air circulation duct, a heat exchanger, which typically uses ambient air as coolant, and a heater, or a heat pump, which uses a refrigerant fluid as coolant and which includes an evaporator and a condenser.

During the cycle of the process air, lint particles come off the laundry and should be filtered before reaching the heat exchanger or the evaporator in order to avoid also the risk that such lint particles could catch fire due to the high temperature of the process air exiting the laundry treatment chamber. Therefore, in laundry dryers, a filter is generally disposed on the air circulation duct, upstream of the heat exchanger or the evaporator, in order to trap the lint particles carried by the process air before they can reach the heat exchanger or the evaporator.

However, lint particles gradually accumulate on the filter during operation making the circulation of the air difficult, so that the energy consumption of the dryer increases and the drying efficiency decreases. Consequently, the filter needs to be often cleaned. To this aim the filter can be removable so that the cleaning operation can be carried out manually by the user, generally washing it, or can be self-cleaning so that the cleaning operation is carried out automatically by means of a cleaning device.

Such cleaning device usually comprises one or more nozzles for spraying a washing liquid onto the face of the filter where the lint accumulates.

In the state of the art the European Patent Application No EP3138953 describes a dryer having a lint filter and a cleaning device providing the automatic cleaning of the filter by rinsing it with condensed water collected to this aim in a receptacle.

An important drawback of the methods of operating the laundry dryers which comprise cleaning the filter by rinsing it with a washing liquid resides on the fact that some lint particles, while the filter is being rinsed by the washing liquid, could aggregate and remain stuck on the filter and, by drying in place, could clog part of the filter reducing the drying efficiency of the dryer in the subsequent laundry drying cycles.

Moreover, the washing liquid used to rinse the filter and accumulating on metal components of the dryer can provoke corrosion problems.

The aim of the present invention is to provide a method of operating a laundry dryer having a lint filter which solves the above mentioned drawbacks, ensuring a high efficiency of the dryer also after the cleaning of the filter and avoiding the onset of corrosion problems.

This objective has been achieved by the method as defined in claim 1. Further achievements have been attained by the subject-matters respectively defined in the dependent claims.

The method of operating a laundry dryer according to the invention comprises, beside a step of rinsing the filter with a washing liquid in order to remove the lint/fluff trapped on it, a step of drying the filter following the step of rinsing the filter. During such filter drying step the cycle fan promoting the process air recirculation through the air recirculation duct is operated so that process air is recirculated and the washing liquid residuals are dried by it. In this manner the risk of rust formation or corrosion as well as the formation of permanent lint/fluff residuals on the filter is avoided and the overall efficiency of the dryer is improved.

In an embodiment, during the step of drying the filter, process air is recirculated through the air circulation duct for a period of time of at least 3 minutes and in a further embodiment, it has a temperature of at least 40°C. In this manner the duration and the efficacy of the filter drying step is optimized.

In an embodiment, when the laundry dryer is a heat pump laundry dryer comprising a heat pump having a compressor for compressing a refrigerant fluid, during the step of drying the filter the compressor of the heat pump is operated in order to dry heat the process air recirculating in the air circulation duct and ensure a quick drying of the filter.

In another embodiment, after the step of drying the filter by means of heated process air a ventilation step is envisaged aimed to decrease the temperature of the air inside the laundry treatment chamber below a preset safety value, so that the user can securely open the door and access the treatment chamber without any burn risk.

In a preferred embodiment the step of drying the filter is performed automatically by the laundry dryer at the end of the filter rinsing step.

In a further embodiment, also the filter rinsing step is performed automatically by the laundry dryer, preferably at the end of every drying cycle, so that the risk that the user may forget to clean the filter is avoided. In this manner the filter is maintained cleaned and dried for the future drying cycle, improving the efficiency of the laundry dryer.

In a different embodiment, the step of rinsing the filter is performed manually by the user and, in a version of this embodiment, the step of drying the filter is performed by the laundry dryer upon receiving a pre-set input from the user, for instance through an user interface of the laundry dryer.

A laundry dryer operatable with a method realized in order to attain the aim of the present invention is illustrated in the attached figures, where:

Figure 1 – is the schematic view of a heat pump laundry dryer.

The elements illustrated in the figures are numbered as follows:

Laundry dryer
Body
Laundry treatment chamber
Air circulation duct
Cycle fan
Filter
Evaporator
Condenser
Door
Nozzle
Supply of washing liquid
Pump

The laundry dryer 1 operatable by a method according to the present invention comprises a body 2 and a laundry treatment chamber 3 arranged in the body 2 and wherein the laundry to be dried is placed, for instance in a drum (not illustrated) arranged in it. The laundry dryer 1 further comprises an air circulation duct 4 connected to the laundry treatment chamber 3 for recirculating the process air PA used to dry the laundry placed in the treatment chamber 3, removing the moisture from it, a cycle fan 5 which is located in the air circulation duct 4 and provides the circulation of the process air PA and one or more filters 6 arranged in the air circulation duct 4 to collect lint/fluff carried by the process air PA.

In particular the laundry dryer 1 illustrated in the attached schematic drawing comprises a heat pump, which uses a refrigerant fluid as coolant to promote the condensation of the water vapor contained in the process air PA before the latter is reintroduced in the treatment chamber 3 and it comprises an evaporator 7, a condenser 8 and a compressor (not illustrated) for compressing the refrigerant fluid. In the laundry dryer 1 illustrated in the attached schematic drawing only one filter 6 is provided upstream of the evaporator 7. The laundry dryer 1 operatable with the present method could however comprise a filter arranged in a different position in the air circulation duct 4, as for instance right below the access door 9 to the laundry treatment chamber 3, or could comprise more than one filter without departing from the scope of protection defined by the present application.

The method of operating the laundry dryer 1 comprises a step of rinsing the filter 6 with a washing liquid in order to remove the lint/fluff trapped on it.

According to the present invention, the method further comprises a step of drying the filter 6 following the step of rinsing the filter 6 during which step of drying the filter 6 the cycle fan 5 is operated and process air PA is recirculated through the air circulation duct 4 for drying the washing liquid residuals.

In this manner the residuals of the washing liquid remaining on the filter 6 and on the air circulation duct 4 are removed, thus avoiding the onset of corrosion or rust formation problems on the metal components of the dryer 1 whereon residuals of washing liquid could generally remain after the rinsing of the filter 6.

Moreover, thanks to the drying step of the filter 6, possible lint particles that couldn’t be removed from the filter during the step of rinsing can be blown away instead of dry in place and partially clog the filter or form permanent residuals on it.

By means of the step of drying the filter 6 also the efficiency of the laundry dryer 1 is improved, since for the whole subsequent drying cycle, which could be started also right after the finishing of a step of rinsing the filter 6, the drying function of the process air PA is completely utilized to remove moisture from the laundry and not partially wasted to remove washing liquid residuals from the filter 6 and the other components in the air circulation duct 4.

In an embodiment, during the step of drying the filter 6 process air PA is recirculated through the air circulation duct 4 for a period of time of at least 3 minutes and preferably for 5 minutes or more. It has been verified that the recirculation of process air PA for this period of time is in fact sufficient to ensure a proper removal of the washing liquid residuals.

In another embodiment, during the step of drying the filter 6 process air PA recirculating through the air circulation duct 4 has a temperature of at least 40°C and preferably of at least 44°C. This ensures that the washing liquid residuals can be removed in a relatively short period of time, hence optimizing the energy consumption of the laundry dryer 1.

In an embodiment where the laundry dryer 1 is a heat pump laundry dryer comprising a compressor, as above specified, during the step of drying the filter 6 the compressor of the heat pump is operated. This ensures that the process air PA recirculating is heated and dried, so that the duration of the step of drying the filter 6 can be maintained within a preferred time period.

In another embodiment, the method of the invention further comprises a ventilation step following the step of drying the filter 6 during which the temperature inside the laundry treatment chamber 3 is decreased below a preset safety temperature value. The ventilation step can be for instance performed by operating the cycle fan 5 without activating the heater and/or the compressor of the laundry dryer 1 or it can be performed by operating a dedicated cooling fan (not illustrated).

The ventilation step allows to relatively quickly decrease the temperature of the air inside the laundry treatment chamber 3 below a preset value which is considered secure to avoid health hazard for the user. The ventilation step moreover ensures that the access to the laundry treatment chamber 3 can be safely allowed to the user without the need to wait for an excessive period of time after the step of drying the filter 6. Advantageously the method further comprises a step of unlocking the door 9 to allow the latter to be opened by the user once the ventilation step is over, i.e. once the temperature in the laundry treatment chamber 6 has reached a value below the preset safety temperature value.

In an embodiment, the laundry dryer 1 comprises a control unit which controls the operation of the laundry dryer 1 and the step of drying the filter 6 is performed automatically at the end of the step of rinsing the filter 6 by means of the control unit which operates the cycle fan 5. In particular the step of drying the filter 6 is preferably automatically performed after each step of rinsing the filter 6. In this manner the step of drying the filter 6 does not depend on the user and it is hence performed regularly ensuring a better efficiency and durability of the laundry dryer 1.

According to an embodiment, illustrated in the attached Figure 1, the laundry dryer 1 comprises a cleaning device having at least one nozzle 10 connected to a supply of washing liquid 11 to spray the washing liquid onto the filter 6, and in particular onto the face of it whereon the lint accumulates, and the step of rinsing the filter 6 is performed automatically by means of the control unit. More in detail, in the embodiment illustrated in the attached Figure 1, the supply of washing liquid 11 is a container where the condensed water is collected to be reutilized for instance for cleaning the filter 6. However such supply of washing liquid 11 could be a different source without departing from the present scope of protection. For performing the step of rinsing the filter 6, the control unit commands the supply of washing liquid to the nozzle or nozzles 10, for instance by operating a dedicated pump 12 or by opening a dedicated valve.

In this manner the whole cleaning and drying process of the filter 6 is performed automatically and in a reliable manner, without requiring any intervention from the user.

In a version of this embodiment, the step of rinsing the filter 6 is automatically performed at the end of each drying cycle by means of the control unit, which commands the supply of washing liquid to the nozzle or nozzles 10 as above specified. In this manner optimal functioning conditions for the laundry dryer 1 are ensured at every drying cycle, removing lint/fluff particles from the filter 6 and drying the filter 6 at the end of every drying cycle.

In a different embodiment, the step of rinsing the filter 6 is performed manually by the user. In this case the filter 6 is removably installed in a location of the air circulation duct 4 easily accessible by the user, so that the latter can remove and clean the filter 6, in particular by washing it. During the step of rinsing the filter 6, hence, the user removes the filter 6, washes it and subsequently reinstalls it in its location on the air circulation duct 4.

In a version of this embodiment, the step of drying the filter 6 is performed by means of the control unit which operates the cycle fan 5 upon receiving a pre-set input from the user. To this aim the user, after having reinstalled the filter 6 in its location on the air circulation duct 4 upon washing it, restart the laundry dryer 1, if necessary, and provides a pre-set input in order to command the performing of the step of drying the filter 6. The pre-set input can be provided by the user by means of a command on the user interface of the laundry dryer 1. For instance, the user could, to this aim, press a specific button on the control panel of the laundry dryer or use a rotating knob to select a preset command which allows the step of drying the filter to be started.

Although the method according to the present invention has been described for a simple dryer, it could be applied mutatis mutandis also to a washer/dryer, without departing from the scope of protection defined by the present application.

The method of operating the laundry dryer 1 according to the present invention allows therefore to operate the laundry dryer 1 constantly in its full functioning conditions. Moreover it prevents corrosion and rust formations problem in the metal components of the laundry dryer 1 arranged in the air circulation duct 4 and that could be impinged by the washing liquid used to rinse the filter 6.

Claims

A method of operating a laundry dryer (1) having a laundry treatment chamber (3) wherein the laundry to be dried is placed, an air circulation duct (4) connected to the laundry treatment chamber (3) for recirculating the process air (PA) used to dry the laundry placed in the treatment chamber (3), a cycle fan (5) which is located in the circulation duct (4) and provides the circulation of the process air (PA) and a filter (6) arranged in the air circulation duct (4) to collect lint/fluff carried by the process air (PA), the method comprising a step of rinsing the filter (6) with a washing liquid in order to remove the lint/fluff trapped on it, characterized in that the method further comprises a step of drying the filter (6) following the step of rinsing the filter (6) during which step of drying the filter (6) the cycle fan (5) is operated and process air (PA) is recirculated through the air circulation duct (4) for drying the washing liquid residuals.
A method of operating a laundry dryer (1) as in Claim 1, characterized in that during the step of drying the filter (6) process air (PA) is recirculated through the air circulation duct (4) for a period of time of at least 3 minutes.
A method of operating a laundry dryer (1) as in Claim 1 or 2, characterized in that during the step of drying the filter (6) process air (PA) recirculating through the air circulation duct (4) has a temperature of at least 40°C.
A method of operating a laundry dryer (1) as in any of the preceding Claims, characterized in that the laundry dryer (1) is a heat pump laundry dryer comprising a heat pump having a compressor for compressing a refrigerant fluid and during the step of drying the filter (6) the compressor of the heat pump is operated.
A method of operating a laundry dryer (1) as in any of the preceding Claims, characterized in that it further comprises a ventilation step following the step of drying the filter (6) during which the temperature inside the laundry treatment chamber (3) is decreased below a preset safety temperature value.
A method of operating a laundry dryer (1) as in any of the preceding Claims, characterized in that the laundry dryer (1) comprises a control unit which controls the operation of the laundry dryer (1) and the step of drying the filter (6) is performed automatically at the end of the step of rinsing the filter (6) by means of the control unit which operates the cycle fan (5).
A method of operating a laundry dryer (1) as in any of the preceding Claims, characterized in that the laundry dryer (1) comprises a cleaning device having at least one nozzle (10) connected to a supply of washing liquid (11) to spray the washing liquid onto the filter (6) and the step of rinsing the filter (6) is performed automatically by means of the control unit.
A method of operating a laundry dryer (1) as in Claim 7, characterized in that the step of rinsing the filter (6) is automatically performed at the end of each drying cycle by means of the control unit.
A method of operating a laundry dryer (1) as in any of the Claims 1 to 6, characterized in that the step of rinsing the filter (6) is performed manually by the user.
A method of operating a laundry dryer (1) as in Claim 9, characterized in that the step of drying the filter (6) is performed by means of the control unit which operates the cycle fan (5) upon receiving a pre-set input from the user.