EP3024969A1

EP3024969A1 - Laundry treatment apparatus with component cleaning arrangement

Info

Publication number: EP3024969A1
Application number: EP13740286.3A
Authority: EP
Inventors: Alberto Bison; Nicola Reid; Giuseppe Rossi
Original assignee: Electrolux Appliances AB
Current assignee: Electrolux Appliances AB
Priority date: 2013-07-24
Filing date: 2013-07-24
Publication date: 2016-06-01
Anticipated expiration: 2033-07-24
Also published as: WO2015010731A1; EP3024969B1

Abstract

The invention relates to a laundry treatment apparatus adapted for laundry drying, in particular condenser-type laundry dryer, exhaust-type laundry dryer, heat pump dryer or washing machine having drying function, the laundry treatment apparatus comprising: an apparatus body (3), a laundry storing compartment (18) for receiving laundry to be dried by passing process air through the laundry storing compartment, a downstream channel (20d) for guiding the process air exhausted from the laundry storing compartment outside the storing compartment and within the apparatus body, an apparatus component arranged at and/or within the downstream channel, wherein the apparatus component is exposed to fluff conveyed in the downstream channel (20d), a cleaning arrangement adapted to clean the apparatus component from fluff by applying liquid in a cleaning cycle, a collector tank (26) adapted to collect the liquid used for cleaning the apparatus component, a liquid level detector (72a-b) adapted to detect the liquid level in the collector tank, and a control unit (9) receiving the signal from the liquid level detector, wherein the control unit (9) is adapted to monitor and process the signal from the liquid level detector (72a-b) for determining the flow rate and/or the amount of liquid supplied during the cleaning cycle to the apparatus component to be cleaned.

Description

5 LAUNDRY TREATMENT APPARATUS

WITH COMPONENT CLEANING ARRANGEMENT

o The invention relates to a laundry treatment apparatus adapted for laundry drying which comprises means for cleaning a component of the dryer.

WO 2009/106926 Al discloses a method for operating a clothes dryer. A pressure sensor is provided in a sump of the dryer for collecting condensate. The pressure sensor is adapted5 to detect a (continuous) water level or a negative air pressure. A negative air pressure

indicates that a fluff filter arranged in a process air channel of the dryer is clogged.

It is an object of the invention to provide an improved laundry treatment apparatus. o The invention is defined in claim 1. Particular embodiments are set out in the dependent claims.

According to claim 1, a laundry treatment apparatus is provided which is adapted for laundry drying, e.g. a condenser-type laundry dryer, an exhaust-type laundry dryer, a heat 5 pump dryer or a washing machine having drying function. The laundry treatment apparatus comprises an apparatus body or casing. A laundry storing compartment for receiving laundry to be dried by passing process air through the laundry storing compartment is arranged in the apparatus body. A downstream channel is provided for guiding the process air which is exhausted from the laundry storing compartment outside the storing

0 compartment and within the apparatus body. An apparatus component is arranged at the downstream channel and/or within the downstream channel. When drying laundry, fluff is generated and conveyed through the process air channel, wherein the apparatus component is exposed to fluff conveyed in the downstream channel. For example an apparatus component may be an (air) filter element arranged in the process air channel such that fluff5 is filtered from process air passing (through) the filter element. Another example for an apparatus component is an (air/air) heat exchanger of a condenser-type dryer or a heat exchanger (evaporator) of a heat pump dryer which are arranged in the process air channel. During a drying operation of the treatment apparatus fluff is continuously collected on the apparatus component which deteriorates its performance. For example the fluff may block an air filter element or the heat exchange performance of a heat exchanger is decreased due to the additional thermal resistance of the accumulated fluff on the heat exchanger surface.

5

To remove accumulated fluff from the apparatus component, the treatment apparatus comprises a cleaning arrangement. The cleaning arrangement is adapted to clean the apparatus component from fluff by applying liquid in a cleaning cycle. A collector tank is adapted to collect the liquid that was used for cleaning the apparatus component. A liquid o level detector is adapted to detect the liquid level in the collector tank. For example a

liquid level detector may comprise one or more of a REED sensor, a floater sensor, a capacitive sensor, an optical sensor, or a conductivity sensor. The (one or more) sensor(s) may be adapted to provide a signal to a control unit of the treatment apparatus when a predetermined liquid level is reached or exceeded. E.g. the liquid detector may comprise a5 single sensor which is adapted to indicate when one (predetermined) liquid level is

reached, e.g. a maximum liquid level and/or a minimum liquid level. Alternatively the detector may comprise a sensor which is adapted to resolve more than one liquid level, e.g. a minimum and maximum liquid level or a continuous (analog) detection of the liquid level. Another example would be a detector comprising (at least) two liquid level sensors, o wherein each sensor is adapted to provide a signal to the control unit when a

(predetermined) level is reached/exceeded. For example a liquid sensor may be arranged in the collector tank or in a cavity hydraulically connected to the tank, such that the level sensor is physically arranged at or in fluid communication with the collector tank. 5 The control unit, which is adapted to receive a signal from the sensor(s), may be the

control unit which also controls the operation of the treatment apparatus. Alternatively the control unit may include a processing logic provided at or assigned specifically to the liquid level detector. The control unit is adapted to monitor and process the signal(s) from the liquid level detector for determining the flow rate and additionally or alternatively the 0 amount of liquid supplied during the cleaning cycle to the apparatus component to be

cleaned. In particular the processing logic in the control unit and/or the level detector is adapted to process the sensor signal and retrieve the flow rate and/or liquid amount by processing the sensor signal. In general the flow rate and/or liquid amount may relate to a value or signal that is indicative of the flow rate and/or liquid amount, respectively. For 5 example a voltage strength, a current strength and/or a digital number is indicative for the flow rate and/or liquid amount. After determining the flow rate and/or liquid amount supplied during a cleaning cycle or flush as described above, at least one of the following information may be derived from the determined flow rate/ liquid amount:

i) liquid amount => the amount of water which was available for the flush, for example to determine whether more flushes are possible/useful,

ii) low flow rate or small liquid amount => presence of some obstacle slowing the water release, e.g. when there is a water filter along the flushing line this could be an indication of the filter clogging degree, and

iii) no liquid flow or water level does not raise => flush failure.

Generally the terms 'liquid amount' and/or 'flow rate' may mean absolute values or relative values of the liquid amount and the flow rate, respectively. And/or these mean minimum values for the liquid amount and the flow rate. For example instead of actually measuring an absolute value of the liquid amount or flow rate, a minimum value thereof can be determined. If the control unit or the logic assigned to the liquid level detector detects the minimum liquid amount or flow rate during the cleaning cycle, it is determined that there is sufficient liquid amount or flow rate, respectively. A decision, whether a failure or lack of efficiency in the cleaning cycle happens, the minimum values of the liquid amount and/or flow rate can be evaluated instead of the absolute values. Further, the flow rate can be detected or determined as a time-dependent value - preferably the 'flow rate' is determined as an average value based on a detected (e.g. minimum) liquid amount divided by the time period in which the detected liquid amount has accumulated.

Thus a plurality of information concerning the executed cleaning operation and condition of the cleaning arrangement may be obtained. In particular, with the above described treatment apparatus an effective release of liquid during a cleaning phase can be evaluated. For example, if an ineffective cleaning phase or a malfunction is determined, this can be indicated to a user immediately, such that the user may take appropriate measures to correct the malfunction. Summarizing the treatment apparatus performance is improved, in particular as the effectiveness of each single cleaning phase can be evaluated.

For example when a low flow rate is detected, e.g. indicating that a liquid filter element along the cleaning path is blocked, a user may be informed to clean the filter. For example a visual or acoustic signal may be provided. Thus a user does not have to check before each treatment apparatus operation whether the filter element needs cleaning, but the user can rely on the treatment apparatus indicating that filter cleaning is necessary. I.e.

convenience of the above described treatment apparatus is improved. Preferably the treatment apparatus comprises a liquid reservoir for storing liquid to be supplied to the cleaning arrangement for cleaning. For example the collector tank is formed by a sump of the treatment apparatus, which is adapted to collect the condensate formed at a heat exchanger. The liquid reservoir may be fluidly connected to the sump (collector tank), such that condensate collected in the sump may be conveyed to the reservoir to be used for a cleaning operation. For example after filling the reservoir with (a predetermined) amount of liquid/condensate, the remaining excess condensate in the sump may be discharged from the treatment apparatus.

The cleaning arrangement may further comprise a valve or a pump operating under the control of the control unit for starting and stopping or dosing the liquid supply to the cleaning arrangement. Preferably the valve or pump is arranged in a supply line between a liquid reservoir and the cleaning arrangement. Thus a cleaning operation can be precisely controlled.

Preferably the control unit is adapted to i) activate or 'start' component cleaning by activating the cleaning arrangement, and ii) in response thereto to monitor the signal status of the liquid level detector. Thus the liquid level monitoring is triggered by starting the cleaning arrangement or starting a cleaning operation. For example an activation may be the opening of a valve to supply liquid or may be the start of operation of a pump pumping liquid to the apparatus component.

The treatment apparatus may further comprise a drain pump, which is associated with the collector tank and adapted to pump liquid collected in the collector tank to one or more of the following: i) a or the liquid reservoir for supplying liquid to the cleaning arrangement, ii) a removable condensate reservoir, and/or iii) an external drain line for draining the pumped liquid to the outside of the apparatus body. For example a removable condensate reservoir may be a removable drawer for user removal of excess condensate and/or contaminated liquid from component cleaning. For example the removable condensate reservoir may be extracted from and inserted into the apparatus body, in particular extracted from and inserted into a reservoir compartment. The control unit may be adapted to operate the drain pump such that the liquid within the collector tank has a reproducible or predefined starting level before the cleaning arrangement is activated. Thus, in connection with time counting (after starting a cleaning operation) a predefined starting condition is created, whereby the precision of amount detection or flow rate detection is increased. Preferably the control unit is adapted to determine the flow rate and/or liquid amount by monitoring and processing the liquid level variations over time and/or the time intervals of liquid level variations. For example the liquid level detector is adapted to detect at least two different liquid levels or is adapted to detect a range of different liquid levels in the collector tank, such that more than one liquid level may be resolved. Thus, in connection with time counting after starting a cleaning operation, a flow rate of the supplied liquid may be determined.

According to an embodiment the control unit is further adapted to monitor the signal of the liquid level detector, and in dependency of the signal of the liquid level detector to activate a or the drain pump associated with the collector tank adapted to drain liquid out of the collector tank. For example liquid may be drained i) to the liquid reservoir for supplying liquid to the cleaning arrangement, ii) to a removable condensate reservoir, and/or iii) to an external drain line for draining the pumped liquid to the outside of the apparatus body. In particular the removable reservoir does not form part of the cleaning path. For example the drain pump is activated when the signal of the level detector indicates that a maximum liquid level of the collector tank is reached or exceeded. Thus the level detector has a double function. On the one hand it is a means for determining the liquid flow rate/ liquid amount during a cleaning operation and on the other hand it is adapted to initiate a draining operation, such that the collector tank does not overflow.

For example the apparatus component to be cleaned is one or more of the following:

a heat exchanger for dehumidifying the process air after passing the laundry storing compartment by condensing humidity from the process air,

a process air filter for filtering process air from fluff,

a heat exchanging surface,

a process air channel surface, or

a condensate collector bottom portion.

Preferably the condensate generated in a condenser type (air/air) heat exchanger or heat pump (evaporator) is collected in the collector tank, such that the condensate is used for cleaning the apparatus component.

Preferably the control unit comprises a time counter, wherein the time counter counts a time from activating the cleaning arrangement or a predefined time after activating the cleaning arrangement and a time point when the level sensor outputs a predefined sensor signal or changes its sensor signal. For example a time counter may be implemented in the processing logic and/or control unit. By measuring (elapsed) time, it can be determined when a predetermined amount of liquid has been supplied or when a predetermined liquid level (according to the predetermined signal of the level sensor) is reached. Either the flow rate may be calculated or it may be determined that minimum liquid amount was flowing (absolutely or within a predetermined time) out of the collector tank. Preferably the collector tank draining pump is deactivated during measuring period (counting period), such that during a measuring period no liquid is drained from the collector tank.

Suppressing activation of the draining pump may be continued after the counting period and/or after reaching the draining level (for example when the collector tank can store more liquid amount than the amount achieved at the draining level), however and preferably the draining pump is activated when the draining level is reached during the cleaning cycle.

Here and in the following, of course, it can only be detected whether a predefined or predefined minimum liquid amount has been achieved - independent of counting the time required from start to achieving the predefined (minimum) liquid amount. If however, the time is additionally observed, it can be detected whether the time to achieving the

(minimum) liquid amount exceeds a threshold time which indicates that the component to be cleaned (e.g. filter) is clogged and has to be serviced.

According to an embodiment, the control unit comprises a time counter and the level detector comprises a first level sensor and a second level sensor. The first and second level sensors are arranged at the collector tank or the reservoir, e.g. the level sensors are physically arranged at the collector tank or are in fluid communication with the collector tank. The time counter counts a time between a time point when the first level sensor outputs a predefined sensor signal or changes its sensor signal and a time point when the second level sensor outputs a predefined sensor signal or changes its sensor signal. From the known amount of liquid between the liquid levels of the first sensor and second sensor a predefined liquid amount can be determined/detected and the time difference can be used for calculating the flow rate. For example the first and second level sensor may be provided by a single sensor that is adapted to resolve two different levels of the liquid.

Preferably the level detector comprises a multi-level sensor or an continuous-level sensor and the control unit comprises a time counter, wherein the control unit is adapted to determine the flow rate and/or the liquid amount using the temporal development of the multiple ones of the level signals or of the changing continuous level signal. For example the flow rate is determined as the increase (gradient) of supplied liquid over time. E.g. if during a cleaning operation a gradient level is detected which is below a predetermined threshold value, i.e. the flow rate is too low, then this may indicate that a filter downstream the collector tank or reservoir is blocked. If the detected gradient is above the

predetermined threshold value, then the cleaning operation has been executed correctly.

5

Preferably the detector device or the laundry treatment apparatus has no level sensor that is assigned to or arranged at or arranged in a fluff filter or is in fluid communication with the filter such as to detect the liquid level within the filter. As described throughout the description, the detector device is adapted to detect a liquid level in a liquid storing tank or o reservoir that are dedicated for at least temporarily storing liquid.

According to a preferred embodiment the control unit is further adapted to process the signal of the level detector for detecting flushing failures, flushing inefficacy or filter clogging and/or to monitor the cleaning arrangement during execution of the cleaning5 cycle, wherein in dependency of the monitoring, a second or more cleaning cycles may be initiated. Preferably the processing of the at least one signal indicates that the flow rate and/or the liquid amount is below a predefined threshold. For example, when it is determined that the liquid amount in the liquid reservoir is low or the liquid amount is below a predefined threshold, and/or the flow rate is below a predefined threshold, the o cleaning cycle is repeated. Thereby it is provided that the component is thoroughly

cleaned. Alternatively or additionally the control unit is further adapted to provide a user signal in dependency of the processing of the at least one signal. A user signal may be indicative of requirement for maintenance, in particular in case of failures and/or when flow rate is too low and indicates clogging of filter and/or other component to be cleaned. 5 E.g. a user signal may indicate that a filter has to be cleaned for example by means of a display and/or optical indicator and/or an acoustic signal, e.g. at user control panel.

Preferably, if - before the end of the cleaning cycle - it is detected that the liquid amount does not further increase or the increase of liquid amount is below a predefined threshold, 0 and/or the flow rate is below a predefined threshold, it is determined that the amount of liquid in the liquid reservoir is low. In response thereto the liquid reservoir may be refilled via the collector tank or alternatively a user signal may be provided to indicate that a or the (extractable) reservoir has to be filled manually. 5 According to an embodiment, if - after a predetermined time after stopping an individual cleaning cycle - a flow rate exceeds a predetermined flow rate threshold, and/or the detected liquid amount increases or exceeds a predetermined threshold of liquid amount or follow-up liquid amount, it is determined that the cleaning arrangement and/or the component to be cleaned are defective or clogged by fluff. In this case for example the component to be cleaned is clogged and cleaning liquid continues to flow to the collector tank a time period well after finishing the cleaning cycle. Thus if after a predetermined time it is detected by the control unit or the logic assigned to the level detection unit that there is still a predetermined flow rate and/or a predetermined liquid amount, clogging by fluff can be concluded. Preferably the detection of the liquid amount and/or flow rate 'after' the predetermined time is combined with the detection of the liquid amount and/or flow rate up to the end of the cleaning cycle (possibly including the detection period

corresponding to the predetermined time) such to further improve fault detection. E.g. if a predetermined liquid amount and/or flow rate are neither detected during the cleaning cycle nor the time well after the cleaning cycle (e.g. a predefined time period after the cleaning cycle) it is concluded that cleaning liquid was missing or is not enough. If the predetermined liquid amount and/or flow rate is detected only in the time well after the cleaning cycle, it can be concluded that there is enough cleaning liquid, but the component is clogged.

Reference is made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying figures, which show:

Fig. 1 a schematic view of a laundry dryer having a heat pump system,

Fig. 2 a schematic block diagram of components of the laundry dryer of Fig. 1,

Fig 3 a schematic view of a cleaning system of the laundry dryer according to

Fig. 1,

Fig 4a-d flow charts and a diagram schematically illustrative embodiments of how to evaluate a cleaning cycle,

Fig 5 a front view of a laundry dryer,

Figs. 6a-b perspective rear views of the dryer of Fig. 3 with partially removed

casing,

Figs. 7a-c a side view and sectional side views of the dryer of Fig. 3, a top view of the dryer of Fig. 3, a rear view of the dryer of Fig. 3, a perspective top view of a reservoir compartment with inserted reservoir of the dryer of Fig. 3, sectional top views of a section of the condensate reservoir and reservoir compartment of Fig. 9, sectional side views of a section of the condensate reservoir and reservoir compartment of Fig. 9, a side view and a sectional side view of the reservoir and reservoir compartment of Fig. 9, a rear view of the reservoir compartment of Fig. 9, a rear view of the condensate reservoir, a sectional front view of the reservoir compartment, a sectional side view and detail of the reservoir and reservoir

compartment of Fig. 9 showing a drain outlet of the compartment, a side view, a perspective view and a rear view of the dryer of Fig. 3 illustrating the arrangement of a drain pipe of the reservoir compartment, a perspective rear view and detail of a dryer according to a further embodiment, and perspective views and sectional side views of an alternative coupling arrangement for a condensate reservoir. Fig. 1 depicts in a schematic representation a laundry dryer 2 which in this embodiment is a heat pump tumble dryer. The tumble dryer 2 comprises a heat pump system 4, including in a closed refrigerant loop 6 in this order of refrigerant flow B: a first heat exchanger 10 acting as evaporator for evaporating the refrigerant R and cooling process air A, a compressor 14, a second heat exchanger 12 acting as condenser for cooling the refrigerant R and heating the process air, and an expansion device 16 from where the refrigerant R is returned to the first heat exchanger 10. Together with the refrigerant pipes connecting the components of the heat pump system 4 in series, the heat pump system 4 forms a refrigerant loop 6 through which the refrigerant R is circulated by the compressor 14 as indicated by arrow B. If the refrigerant R in the heat pump system 4 is operated in the transcritical or totally supercritical state, the first and second heat exchanger 10, 12 can act as gas heater and gas cooler, respectively.

The expansion device 16 is a controllable valve that operates under the control of a control unit 9 (Fig. 2) of the dryer to adapt the flow resistance for the refrigerant R in dependency of operating states of the heat pump system 4. Alternatively the expansion device may be a fixed cross-section valve or capillary tube. Alternatively or additionally the compressor may be a variable- speed compressor by which the conveyance rate for refrigerant pumping can be varied.

The process air flow A within the treatment apparatus 2 is guided through a compartment 18 of the treatment apparatus 2, i.e. through a compartment 18 for receiving articles to be treated, e.g. a drum 18, which may be rotated by means of a drum motor 17. The articles to be treated are textiles, laundry 19, clothes, shoes or the like. In the embodiments described here these are preferably textiles, laundry or clothes. The process air flow is indicated by arrows A in Fig. 1 and is driven by a process air blower 8 or fan. The process air channel 20 guides the process air flow A outside the drum 18 and includes different sections, including the section forming the battery channel 20a in which the first and second heat exchangers 10, 12 are arranged. The process air exiting the second heat exchanger 12 flows into a rear channel 20b in which the process air blower 8 is arranged. The air conveyed by blower 8 is guided upward in a rising channel 20c to the backside of the drum 18. The air exiting the drum 18 through the drum outlet (which is the loading opening of the drum) is filtered by a fluff filter 22 arranged close to the drum outlet in or at the channel 20. Fluff filter 22 may be omitted when for example filter elements 40 or 70e are used which can be cleaned by liquid flushing described below in connection with Figs. 4a-4d. When the heat pump system 4 is operating, the first heat exchanger 10 transfers heat from process air A to the refrigerant R. By cooling the process air to lower temperatures, humidity from the process air condenses at the first heat exchanger 10, is collected there and drained to a condensate collector 26, which is preferably arranged below the heat 5 exchangers 10, 12. The process air which is cooled and dehumidified after passing the first heat exchanger 10 passes subsequently through the second heat exchanger 12 where heat is transferred from the refrigerant R to the process air. The process air is sucked from exchanger 12 by the blower 8 and is driven into the drum 18 where it heats up the laundry 19 and receives the humidity therefrom. The process air exits the drum 18 and is guided in o front channel 20d back to the first heat exchanger 10. The main components of the heat pump system 4 are arranged in a base section 5 or basement of the dryer 2.

A cooling air blower 24 or fan unit controlled by the control unit 9 of the dryer 2 may be arranged close to the compressor 14 to remove heat from the compressor 14, i.e. from the5 heat pump system 4, during a drying operation. The cooling air flow, which is an ambient air flow in the embodiments, is actively driven by the cooling air blower 24 and is taking heat from (the surface of) the compressor 14. By transferring heat from the compressor 14, during a normal operation mode of the heat pump system 4 (following to its warm-up phase), thermodynamic balance is achieved between the closed loops of the process air o loop and refrigerant loop 6.

As schematically shown in Fig. 1 and in more detail in Fig. 3, during dryer operation condensate is collected in the condensate collector 26 or basement tank below the heat exchangers 10, 12. By means of a drain pump 42 and drain pipe 41 collected condensate is 5 pumped to a condensate reservoir 28, which is arranged drawer- like in a reservoir

compartment 30 at an upper portion of the dryer casing 3. A front 27 or front panel of the reservoir drawer 28 is shown in Fig. 4 having a handle for user inserting and pulling-out operation. The reservoir 28 comprises an outlet 29 which is fluidly connected to a supply line 32 or inlet of the supply line 32 when the reservoir 28 is inserted into the reservoir 0 compartment 30. In particular the reservoir comprises a closing element 48 or valve, which is adapted to be opened by an actuating element 54 of the reservoir compartment 30 when the reservoir 28 is inserted into the compartment 30. When the reservoir 28 is inserted in its operating position within the compartment 30, the reservoir outlet 29 is permanently open. Additionally or alternatively the actuating element or part thereof may be provided at5 the reservoir 28. In Fig. 3 the outlet 29 and closing element 48 are exemplary depicted at a bottom or base of the reservoir 28. Alternatively the outlet 29 may be arranged at a rear portion of the reservoir 28. As schematically shown in Fig. 3, a rinsing or flushing pump 44 which is controlled by the control unit 9 is adapted to pump condensate via the supply line 32 from the the reservoir 28 to the first heat exchanger 10 or optionally to a filter element 40 (Fig. 1) upstream the 5 first heat exchanger 10 to rinse or wash the respective component. By means of the

supplied liquid collected fluff is washed off a (front) surface of the heat exchanger 10 or the filter element 40.

The rinsed off fluff and rinsing liquid is collected in the condensate collector 26 arranged o below the heat exchangers 10, 12. Controlled by the control unit 9 a drain pump 42 pumps the collected liquid via a drain pipe 41 back to the reservoir 28. A liquid level sensor 72a is provided which is adapted to provide a signal to the control unit when a threshold value of a liquid level in the collector 26 is reached, then the control unit 9 may activate the drain pump 42. The function of the liquid level sensor is described in more detail below (Figs.5 4a-d).

To remove fluff from the liquid, one or more fluff filter(s) 70a-e or filter elements may be provided (Fig. 3). For example a fluff filter 70a may be arranged at an inlet of the reservoir 28, such that only filtered liquid enters the reservoir 28. Additionally or alternatively a fluff o filter 70b may be arranged at the reservoir outlet 29, such that fluff is filtered from the liquid before the liquid passes the flushing pump 44. A fluff filter 70c may be arranged at any portion of the supply line 32, wherein it is advantageous to place the fluff filter 70c such that it is conveniently accessible from a front or top portion of the dryer casing 3 for cleaning. Further, a fluff filter 70d may be arranged upstream the drain pump 42, e.g. in the 5 collector 26, such that liquid is filtered before it enters the drain pump 42, which improves the performance of the pump 42.

Additionally a process air (fluff) filter 70e may be arranged in the process air channel 20d upstream the heat exchanger 10 to remove fluff from the process air before the process air 0 reaches the heat exchangers 10, 12. In this embodiment the flushing duct 58 or supply line outlet 57 is arranged such that the air filter 70e is washed or cleaned in a cleaning cycle or cleaning operation. The supplied liquid and the washed-off fluff may be collected in the condensate collector 26, e.g. to be discharged from the dryer 2 and/or to be supplied to the reservoir 28. In this embodiment fluff is removed from the process air before it passes the5 heat exchanger 10, such that the heat exchanger 10 surface remains free of fluff at all

times. Thereby the heat exchanger performance is at a high level throughout a drying operation of the dryer 2. As schematically depicted in Fig. 3, the supply line 32 comprises a siphon formed by a rising portion 34, a communicating portion 36 and a descending portion 38. In the following an exemplary rinsing or cleaning operation is described.

When the dryer 2 starts operating condensate is generated at the first heat exchanger 10 as described above. The condensed liquid is collected in the condensate collector 26 and subsequently pumped by means of drain pump 42 and drain pipe 41 into the reservoir 28. For example the drain pump 42 may be operated in dependency of the signal of the liquid level sensor 72a arranged in the condensate collector 26 as described above. E.g. the drain pump 42 may be repeatedly switched on and off in dependency of the water level in the collector 26.

Figs. 4a-c show exemplary schematic flow charts to illustrate how a cleaning operation of an apparatus component is evaluated, i.e. to determine whether the cleaning operation has been effective.

The flow rate and/or the amount of liquid supplied during a cleaning operation or cycle is determined using the level sensor 72a (alternatively or additionally by using sensor 72b). The sensor 72a (and sensor 72b) may be selected from a REED sensor or any other level sensor which is adapted to provide a signal to the control unit 9 when a predetermined water level in the tank 26 (or the reservoir 28) is reached or exceeded.

The preferred embodiments described now and as shown in Figs. 4a-c are directed to a treatment apparatus using (only one) level sensor 72a in tank 26 for determining cleaning efficiency and/or faults. The sensor 72a is adapted to provide a signal to the control unit 9 when liquid in the tank 26 reaches or exceeds a maximum level l_max.

As shown in Fig. 4a, a cleaning cycle is initiated after a drying cycle has been finished. Here the cleaning cycle is starting after the drying cycle which preferably is executed after every drying cycle or after a predetermined number of drying cycles or upon request by the control unit (e.g. process air flow resistance is high). In other embodiments the cleaning cycle may be performed during the running drying cycle, e.g. as an independently executed subroutine.

In the process of Fig. 4a, next the drain pump 42 is activated such that liquid collected in the tank 26 is pumped into the reservoir 28. Preferably drain pump 42 is operated a predetermined pumping time which ensures under normal operating conditions that the reservoir is completely emptied (up to a remaining condensate amount that can not be pumped away and/or flows back when pump is stopped). Thus a predefined starting level, namely the minimum level l_min is the starting condition for the following liquid flushing. Alternatively the level detector 72a is adapted such as to detect at least two water levels, namely the maximum water level l_max and the minimum water level l_min. Then, when the liquid level in the tank 26 reaches the predetermined minimum level l_min, the drain pump 42 is stopped. Also in this embodiment a predetermined start condition or water level is provided in the tank 26.

Subsequently the flushing pump 44 is operated and/or the valve 48 is opened. The cleaning operation or flushing operation is started by supplying the liquid to the component to be cleaned (here filter 70e). At the same time and triggered by the start of the cleaning operation (start of pump 44/ opening of valve 48) a time counter is activated and starts to count the duration of liquid supply to the component to be cleaned.

During the cleaning operation liquid is supplied from the reservoir 28 through the flushing duct 58 and nozzle 57 to the filter element 70e (alternatively to the heat exchanger 10). The supplied liquid flows downwards into the tank 26, where it is collected. When the liquid level in the tank 26 reaches the maximum level l_max, the level sensor 72a provides a signal to the control unit 9. In response to the sensor signal the counter is stopped and the elapsed time At is stored in the control unit 9. Based on the determined value of At and the known amount of liquid (volume between l_min and l_max) the flow rate during the cleaning operation is calculated and also stored in the control unit.

Additionally (not depicted) the flushing pump 44 may be stopped when stopping the counter. Then the amount of liquid supplied to the component to be cleaned is determined by detecting the maximum level l_max. Preferably the pump 44 and/or valve 48 are activated a predetermined time. Under normal operation conditions the flow rate of liquid is known when the pump and/or valve are activated and/or the amount of liquid available for flushing (see above in connection with chambers 62/64) is restricted. Then the amount of flushing liquid used in one flushing cycle is determined by the activation time or by the restricted available amount. Preferably this amount is more than the amount which is received by the collector tank 26 between the minimum and maximum levels l_min to l_max to allow the detector 72a to provide the maximum signal at l_max. When in the above step the calculated flow rate is below a predetermined minimum value, this may indicate that a filter element along the flushing duct 58 is (at least) partially clogged. This may be indicated to a user via an acoustic or visual signal, such that the user is alerted to clean the respective filter element or component to be cleaned.

5

When the calculated flow rate is above the predetermined minimum value, the cleaning operation has been effective and the apparatus component may be flushed once more. For repeating the flushing of the component, the above described cleaning cycle is run through (a least) once more. For example the component to be cleaned is flushed a predetermined o number of times which is controlled by the control unit 9. For example depending on the detected value of the flow rate the number of flushes (one flush = one run through cleaning cycle of Fig. 4a) may be set. Note that by first starting pump 42, reservoir 28 stores again liquid sufficient for the next flushing. 5 The flow diagram of Fig. 4a may provide the embodiment that, if it is detected that the flow rate was too low, instead or before alerting the user, at least one further time the cleaning cycle may be executed for repeating the flushing of the component to be cleaned - eventually to thereby remove a clogged state of the component to be cleaned. In this embodiment the cleaning cycle may be repeated a predefined number of times and if it was o repeatedly unsuccessful (flow rate too low), then the user may be alerted for cleaning the filter.

Fig. 4b and 4c show flow charts based on the flow chart shown in Fig. 4a. Unless otherwise mentioned the illustrated steps of Fig. 4a which are (partially) shown in Figs. 4b- 5 c correspond to each other.

In Figs. 4b-c the counted or elapsed time t until the liquid level in tank 26 reaches the maximum level l_max is (additionally) continuously evaluated. It may occur that the elapsed time t exceeds a predetermined threshold value t_crit when the level in tank 26 does not 0 reach its maximum level (i.e. the sensor 72a does not provide a signal) after a

predetermined time (t_crit).

As shown in Fig. 4b, exceeding t_crit may indicate that i) a filter is clogged, ii) the amount of liquid in reservoir 28 was too small, or iii) the flushing arrangement is defect (pump 445 (valve), conduit 58, nozzle 57). In response to exceeding t_crit the flushing pump 44 is stopped and a user is alerted via an acoustical or visual signal that i) a filter element 70a/b/c/d has to be cleaned, ii) water has to be filled in the reservoir 28 and additionally or alternatively iii) a support service should be called.

As described above, exceeding t_crit may indicate that the amount of liquid in the reservoir 28 used for the cleaning operation (flush) was so small, that the liquid level in tank 26 does not reach its maximum level l_max. Fig. 4c shows an alternative solution for this case, in comparison to the option of alerting a user to fill water in the reservoir 28 as shown in Fig. 4b. As shown in Fig. 4c, after exceeding t_crit, the drain pump 42 is started again (and the flushing pump 44 stopped / valve 48 closed), such that the (small) amount of liquid in the tank 26 is pumped back into the reservoir 28 to be used for a further flushing of the apparatus component. I.e. the apparatus component to be cleaned is flushed, but with a smaller amount of liquid. For example in this case the control unit 9 could be adapted to provide a predetermined number of flushes with the small amount of liquid.

In particular the embodiments depicted in Figs. 4b and 4c could be combined. For example, if after the predetermined number of flushes as shown in Fig. 4c, the maximum level l_max in tank 26 is still not reached, the control unit 9 may be adapted to switch from the control according to Fig. 4c to the control according to Fig. 4b. I.e. if after a

predetermined number of flushes (e.g. 4 times) t_crit is still exceeded, a user is alerted i) to clean filter element(s), ii) fill water in the reservoir 28 and/or iii) call a support service.

The diagram of Fig. 4d schematically shows the rising liquid level in the tank 26 over time during a cleaning operation. The start of the flushing operation (activation of pump 44/ opening valve 48) is indicated at time point t₀, which also indicates the starting point of the time counter counting the elapsed time after starting the cleaning operation.

Fig. 4d shows three cases indicated with roman numerals I, II, III. Case I exemplary illustrates an effective cleaning operation, i.e. the "flush" had a flow rate which is sufficient to effectively clean the filter element 70e (or any other apparatus component). The maximum liquid level l_max in the tank 26 is reached at time point t_\.

Case II shows that the maximum liquid level l_max is reached at a later time point t₂. This indicates a reduced flow rate. For example the filter element 70b or 70c along the flushing duct 58 is (partially) clogged. When the control unit 9 detects such a low flow rate, i.e. a flow rate below a predetermined threshold value (min flow rate) a signal may be provided to inform a user that a filter element 70b/c/d has to be cleaned (Figs. 4a-c).

Case III shows that the maximum liquid level l_max is reached at an even later time point t₃. 5 This may indicate that a filter element 70b/c/d is completely blocked. In this case the

cleaning operation or cycle may be completely stopped and a user may be alerted that i) a filter element 70a/b/c/d has to be cleaned, ii) water has to be filled in the reservoir 28 and additionally or alternatively iii) a support service should be called as described above. The dash-dotted level curve III shows a delay in liquid arrival in the collector tank 26 which is o indicative of a temporal damming or retaining of the liquid on its path from reservoir 28 to collector tank 26 - e.g. a temporal retaining in the filter 70e.

According to an alternative embodiment a level detector (in reservoir 28 or tank 26) is adapted to resolve more than one liquid level. For example a sensor 72b is adapted to5 detect the liquid level in the reservoir 28 continuously. I.e. the amount of liquid stored in the reservoir 28 can be precisely monitored at all times. Also in this case the flow rate of a cleaning operation can be easily determined from the known amount of liquid in the reservoir 28 (used for one cleaning operation) and the elapsed time At since starting a flushing operation which is counted by a counter as described above. Correspondingly to o the above embodiments the calculated flow rate can be evaluated to determine whether the cleaning operation has been effective. Also the flow rate can be calculated in higher temporal resolution (using short time periods and the level at the start and end of the respective time period) such that a more detailed analysis of the temporal flow rate can be used for determining the reason for a poor flushing result or a fault in the flushing

5 arrangement. As an example from dotted level curve IV it can be determined that the flow rate is low (filter cleaning required) and that the available amount of liquid is too low for effective flushing (e.g. the user can be requested to fill some water into reservoir 28).

According to an embodiment the reservoir 28 comprises a first compartment 62 (rinsing or 0 flushing volume) and a second compartment 64 (retaining volume) which are divided by a separation wall 66 comprising small liquid passages 68a-c (Fig. 13c). The liquid from the collector 26 is supplied to the first compartment 62. The reservoir inlet or the outlet of the drain pipe 41 is arranged such that liquid is fed into the first compartment 62. When not operated the flushing pump 44 allows liquid to freely flow through the pump 44 in a

5 forward or in a reverse conveying direction when the pump is switched-off. As the

reservoir outlet 29 is permanently open, the supply line 32 is filled up until the liquid level in the supply line 32 (comprising the rising portion 34) corresponds to the liquid level in the first compartment 62. I.e. the supply line 32 and reservoir 28 form communicating 'pipes' in this way. As the supply line 32, in particular the communicating portion 36 thereof, is arranged higher than the maximum liquid level of the reservoir 28, the siphon structure of the supply line 32 prevents that the reservoir 28 is unintentionally emptied, i.e. 5 it is prevented that a rinsing operation starts unintentionally when the pump is not

operated.

When the liquid level in the first compartment 62 exceeds the height of the separation wall 66, liquid flows over the separation wall 66 and fills the second compartment 64.

o Additionally liquid flows via liquid passages 68a-c from the first compartment 62 to the second compartment 64 with a lower flow rate as compared to an overflow rate over the separation wall and/or the conveyance flow rate of pump 44.

In another embodiment (not shown), the separation wall 66, which is aligned vertically in5 the above embodiment, may be replaced by a separation wall that is oriented horizontally, is oriented inclined or is oriented partially vertical, inclined and/or horizontal. Note: All orientation relate to the operational positioning of the laundry dryer. Thus the first and second compartments may not necessarily be arranged side by side but can be arranged above each other or partially side by side and partially above each other. In any case the o one or more liquid passages 68a-c are provided at a lower part of the separation wall such that a controlled low flow rate of liquid can flow from the second to the first compartment in case of liquid level difference. An overflow between the first and second compartment may also be provided. If the condensate flowing into the condensate reservoir is first supplied to the second compartment, it can flow to the first compartment through the liquid 5 passage(s) (and possibly via the overflow therebetween). The above and below

respectively applies to such another embodiment.

Generally, to start a rinsing or cleaning operation, e.g. after a predetermined operation time of a drying program has elapsed or after the end of a drying cycle, the flushing pump 44 is 0 activated via the control unit 9. As described in connection with the embodiments

illustrated in Figs. 4a-d a predetermined starting condition has to be met before starting a cleaning operation. The flushing pump 44 pumps liquid from the reservoir 28 via the supply line 32 to an outlet of the supply line, in particular to the flushing duct 58 which comprises nozzle 57 arranged such that e.g. the heat exchanger 10 front surface is rinsed5 by the supplied liquid (in this embodiment no air filter 70e is provided). The supply line 32 may be attached to the duct 58 and nozzle 57 such that the supply line 32 is fluidly connected to the duct 58 and nozzle. Alternatively the outlet of the supply line may be arranged such that supplied liquid is directly supplied to the component of the dryer 2 to be cleaned, e.g. to the air filter 70e.

When the first compartment 62 is empty, i.e. all liquid stored therein has been supplied to the component to be cleaned, and the flushing pump 44 continues to operate, the pump 44 starts to pump air from the empty compartment 62 into the supply line 32 until the air reaches the communicating portion 36, whereby the siphon-effect is eliminated. Depending on pump operation conditions and when pump 44 is stopped, liquid draining in the descending portion 38 results in air entering through nozzle 57 or outlet which rises to the communicating portion 36 thereby also interrupting the siphon effect. The supply line 32 or the liquid supply system is again in its initial state, where liquid can be supplied into the first compartment (from the condensate collector 26 or the second compartment 64) while the communicating portion 36 arranged above the highest reservoir liquid level prevents an unintentional emptying of the reservoir 28.

The rinsing liquid with the washed off fluff is collected in the condensate collector 26 after the rinsing operation. For removing the (dirty) liquid from the dryer 2, the collected liquid may be pumped via drain pump 42 back into the first compartment, basically as described above. The user may extract the reservoir 28 from the reservoir compartment 30 to empty the reservoir 28.

When a user extracts or pulls out the reservoir 28, the reservoir outlet 29 is closed by the closing element 48 or valve, such that the collected liquid is retained in the reservoir 28. Alternatively an additional drain outlet (not depicted) is fluidly connected via a valve to the drain pipe 41, whereby the collected dirty rinsing liquid may be directly drained from the dryer 2 by means of the drain pump 42.

The reservoir compartment 30 comprises an outlet 31 such that when liquid spills during removal of the reservoir 20 or when the reservoir 28 is overflowing, liquid enters the reservoir compartment 30 and is drained through outlet 31. The outlet 31 is connected via a drain pipe 46 to the condensate collector 26. The outlet 31 is permanently open and spilled liquid is immediately discharged to the condensate collector 26.

As described above, liquid from the second compartment 64 may flow to the first compartment 62 via the liquid passage 68a-c. The liquid passage 68a-c is arranged close to a base or bottom of the reservoir 28. When the liquid level of the second compartment 64 is low, it is provided that liquid flows with a low flow rate towards the (empty) first compartment 62 until the liquid levels in first and second compartment 62, 64 are leveled out. The cross-section of the liquid passage 68a-c is small, such that during emptying the first compartment 62 by means of the flushing pump 44 little or almost no liquid flows from the second compartment 64 to the first compartment 62. However, after a pause period following to a first pump/flushing operation, for example a second rinsing operation may be executed, wherein the liquid slowly flown from the second compartment 64 to the first compartment 62 may be used as rinsing liquid as described above.

In the following different embodiments of a laundry dryer are described. Elements and features corresponding to the above schematically depicted dryer 2 of Figs. 1 to 3 are marked with corresponding reference signs. Unless otherwise mentioned, the elements, features and functions of the below described embodiments correspond to the above described elements, features and functions. Fig. 5 shows a front view of a dryer 2 comprising an input panel 7 for user input and an outer casing 3 or housing having a loading door 15 for loading laundry to be dried into the drum 18 arranged in the casing 3. Figs. 6a-b show perspective rear views of the dryer of Fig. 3, wherein the top and side portions of the casing 3 are removed to show the arrangement of dryer components.

The reservoir compartment 30 is arranged at a top portion of the dryer 2, wherein the extractable reservoir 28 is inserted into the compartment 30. At the rear of the

compartment 30 the supply line 32 can be seen which runs from the reservoir 28 or compartment 30 down to the flushing pump 44. From the flushing pump 44 the rising portion 34 of the supply line is guided back up. The communicating portion 36 of the supply line is arranged above a highest liquid level of the reservoir 28 as described above and is formed in a space-saving manner as a flat pipe. The descending portion 38 of the supply line 32 is guided downwards towards the flushing duct 58 which is arranged on top of the battery channel 20a which houses the first and second heat exchanger 10, 12.

The drain pump 42 is arranged at a bottom rear portion of the base section 5 of the dryer. The drain pump 42 pumps liquid from the condensate collector 26 (Figs. 7b-c) to the reservoir 28 as described above. Figs. 7a-c show a side view and sectional side views of the dryer of Fig. 3. Fig. 7a shows a side view of the dryer 2, wherein the side cover or casing 3 is removed. Figs. 7b and 6c show sectional side views of the dryer 2. Fig. 7b shows a sectional side view in the plane of the reservoir outlet 29 and Fig. 7c a sectional side view in a plane of the descending portion 38 of the supply line 32.

When the reservoir 28 is inserted, the reservoir outlet 29 (i.e. the closing element 48) is permanently opened as described above. In particular the coupling arrangement 54 comprises an actuating element in form of a protruding bolt or pin which opens the closing element 48 by pushing it open when inserting the reservoir 28 into the reservoir

compartment 30. As shown in Fig. 7c, the descending portion 38 of the supply line 32 opens into the flushing duct 58 which is arranged on top of the battery channel 20a. The duct 58 comprises a nozzle 57, i.e. the supply line outlet, which is arranged above a front surface of the first heat exchanger 10. I.e. when liquid is supplied through the supply line 32, the front surface of the heat exchanger 10 is rinsed or washed as described above.

The condensate collector 26 is arranged below the heat exchangers 10, 12 and extends to the back or rear of the dryer 2 where the drain pump 42 is arranged, which pumps the collected liquid back into the reservoir 28 as described above. Fig. 8 shows a top view and Fig. 9 a rear view of the dryer 2 of Fig. 3. In Fig. 9 the flow direction of the conveyed liquids during a rinsing operation are indicated by arrows. As shown in Fig. 8, the collector drain pipe 41 opens into the reservoir inlet which is arranged on top of the reservoir 28. The portion of the collector drain pipe 41 running across the rear of the dryer 2 has been omitted for clarity.

Fig. 10 shows a perspective top view of the reservoir and reservoir compartment 30 of the dryer 2 of Fig. 3. In this embodiment portions of the supply line 32 are arranged at the rear of the compartment 30 in a space-saving manner. In particular the communication portion 36 is formed in one piece with a portion of the rising and descending portions 34, 38, wherein each end comprises a connecting socket or pipe socket for attaching thereto a

(flexible) hose which forms the remaining part of the supply line 32.

Fig. 11a shows a sectional top view of a portion of the condensate reservoir 28 and Fig. 1 lb shows a sectional top view of a portion of the reservoir 28 inserted into the reservoir compartment 30. In Fig. 1 la the closing element 48 is closed as the reservoir 28 is removed from the compartment 30, i.e. the closing element 48 provides that collected liquid in the reservoir 28 is safely retained. The closing element 48 comprises a spring- biased lever 50 which pushes the closing element 48 against the inner wall of the reservoir 28.

Fig. 1 lb shows the reservoir 28 when completely inserted in the reservoir compartment 30, i.e. the reservoir 28 is in its operating position. The coupling arrangement 54, here the protruding pin pushes the closing element 48 into the reservoir 28 such that the reservoir outlet 29 is opened and the reservoir 28 is fluidly connected to the supply line 32.

Corresponding to Figs. 1 la-b, Figs. 12a-b show sectional side views of the removable condensate reservoir 28 (Fig. 12a) and of the reservoir 28 inserted into the reservoir compartment 30 (Fig. 12b). In Fig. 12a an elastic sealing element 52 of the closing element 48 can be seen which abuts at a sealing surface of the reservoir 28 to provide a leak-proof seal when the reservoir 28 is pulled out of the compartment 30. In Figs. 12a-b an elastic sealing element 53 is present which is provided to prevent leakage of water when the removable reservoir is in communication with the supply line housing 32.

Figs. 13a-b show a side view and a sectional side view of the reservoir compartment 30 with inserted condensate reservoir 28. In Fig. 13b the first and second compartments 62, 64 are shown with the separating wall 66 between them. The separating wall 66 comprises the liquid passage 68a-c in form of several pinholes (Fig. 14c) close to the bottom of the reservoir 28. Further a filter element 70a is arranged at the inlet of the reservoir 28, i.e. at the outlet of the collector drain pipe 41. Thus liquid is filtered before being collected in the reservoir 28. The filter element 70a which is associated to the reservoir 28 can be easily cleaned when the reservoir 28 is extracted from or pulled out of the compartment 30.

Figs. 14a-c show a rear view and sectional views of the reservoir 28 and reservoir compartment 30. Fig. 14a shows a rear view of the compartment with the supply line 32 arrangement attached thereto. In Fig. 14b the supply line 32 arrangement is omitted, such that the position of the inserted reservoir 28 can be seen. Fig. 14c is a sectional front view which shows the separating wall 66 and the pinholes forming the liquid passage 68a-c between the first and second compartment 62, 64 as described above.

Figs. 15a-b show a sectional side view and detail of the reservoir 28 and reservoir compartment 30 in the plane of the outlet 31 of the compartment 30. It can be seen that the outlet 31 is formed as a pipe socket at the lowest portion of the compartment 30 which is permanently open. I.e. it is provided that any spilled liquid is immediately drained from the compartment 30 via outlet 31 and drain pipe 46 into the condensate collector 26 as described above.

Figs. 16a-c show a side view, a perspective view and a rear view of the dryer 2 of Fig. 3, 5 wherein the supply line 32 is omitted to illustrate the arrangement of the drain pipe 46 connecting the compartment 30 to the condensate collector 26. The compartment drain pipe 46 is connecting the reservoir compartment outlet 31 (Fig. 15b) to the condensate collector 26, wherein the drain pipe 46 is guided vertically or essentially vertically downwards from the outlet 31 towards the condensate collector 26. I.e. liquid is guided by o means of gravity in the shortest (and fastest) possible way into the collector 26, wherein due to the vertically arranged drain pipe 46 and therefore high flow rates the risk of clogging the drain pipe 46 is reduced.

Figs. 17a-b show a perspective rear view and a detail of a dryer 2' according to a further5 embodiment. Unless otherwise mentioned, elements, features and functions of the dryer 2' correspond the elements, features and functions of the dryer 2 described above.

In contrast to the above described dryer 2, the dryer 2' of Fig. 17 comprises a flushing pump 44' which is arranged behind the backside or rear of the compartment 30. In

o particular the outlet 29 of the reservoir 30 is directly connected to the flushing pump 44' with a minimum of supply line 32 or pipe inbetween. In this embodiment the supply line 32 is considerably shorter than in the embodiment above. Due to shorter supply line 32 or pipes the pressure drop during the operation of the flushing pump 44' is reduced. Further, less liquid remains in the dryer after a drying cycle, as the rising portion 34' of the supply 5 line 32 is much shorter than in the above embodiment. The flushing pump 44'is supported by a supporting structure 74 which is arranged here at the rear side wall or region of the reservoir compartment 30.

Figs. 18a-d show perspective views and sectional side views of an alternative coupling 0 arrangement 54' for a condensate reservoir 28'. The condensate reservoir 28' and its

coupling to the supply line 32 as described in the following may be implemented in any of above described embodiments of dryers 2, 2'. In Figs. 18a-d the reservoir compartment for housing the reservoir 28' is not depicted. Unless otherwise mentioned the elements, features and components of the above described reservoir 28 and compartment 30 may be5 implemented in the below described embodiment of the reservoir 28'. For example the reservoir inlet or compartment outlet 31 may be implemented in the below described reservoir 28' and corresponding compartment. Fig. 18a shows a perspective view of a detail of the reservoir 28' with a closing element or valve 48' in a closed state and Fig. 18b shows a sectional view of the detail. The valve 48' comprises a (stationary) valve body 82 which is connected or fixed to the reservoir 28' or main body of the reservoir 28', wherein locking hooks 98a-b are provided which are formed integrally with the valve body 82. Within the valve body 82, in particular in a body pipe section 94 of the valve body 82, a moveable valve element 80 is guided. The valve element 80 comprises an element pipe section 96 which is guided by the valve body 82, i.e. the body pipe section 94 of the valve body 82. An outer surface of the element pipe section 96 is guided on or slides along an inner surface of the body pipe section 94, e.g. when the valve element 80 is pushed into the valve body 82 when inserting the reservoir 28' into the compartment 30. The valve element 80 comprises a hollow profile portion, in particular a hollow profile end portion which faces into the reservoir 28'. The hollow profile portion comprises four passages 92a-c (only three visible in Fig. 18b) through which the reservoir 28' is filled and emptied, i.e. through which the condensate flows when the reservoir 28' is inserted in the dryer 2, 2' and the condensate is discharged after extracting the reservoir 28' from the dryer 2, 2'.

The valve 48' comprises several gaskets 90a-c in form of O-rings. Gasket 90c is arranged on the moveable valve element 80 and provides a tight sealing between a first sealing surface 84 (Fig. 18d) of the the valve body 82 and a second sealing surface 86 of the valve element 80. A spring element 88 (Fig. 18c) provides that the valve element 80 and the valve body 82, i.e. the respective sealing surfaces 84, 86, are pressed tightly together when the reservoir 28' is extracted from the dryer 2, 2' or reservoir compartment, such that the valve is in the closed state and stored condensate cannot be spilled accidentally.

Fig. 18c shows a cross-sectional side view of the reservoir 28' before coupling the reservoir 28' to a coupling arrangement 54' attached to the supply line 32 or supply line inlet 56. The spring element 88 pushes the valve element 80, i.e. the second sealing surface 86, against the first sealing surface 84 of the valve body 82, such that the valve 48' is in the closed state. The (open) end of the moveable valve element 80 facing the outside of the reservoir 28' has a maximum outlet diameter d. When actuating the valve 48', the valve element 80 is pushed along the valve axis into the (stationary) part of the valve 48', i.e. the valve body 82. An actuation length of the valve element 80, i.e. the length the valve element 80 that has to be moved from the closed valve state to the (completely) open valve state, is in the range of 5 mm to 15 mm. In particular the valve 48' is (completely) open when the complete cross-section of all passages 92a-c is exposed to the inner volume of the reservoir 28'.

Fig. 18d shows a cross-sectional side view of the reservoir 28' after coupling the reservoir 5 28' to the coupling arrangement 54' arranged at the supply line inlet 56, i.e. after fully

inserting the reservoir 28' in its compartment. The valve 48' is actuated, i.e. the valve element 80 is pushed into the valve body 82 such that the passages 92a-c are exposed to the interior of the reservoir 28', i.e. the valve is in the open state. In particular the actuation length of the valve element 80 is selected such that at the end of the actuation movement o the passages 92a-c are fully exposed.

In particular the sum of the cross-sections of all passages 92a-c is equal to or

approximately equal to the cross-section of the maximum axial opening of the valve element 80. Thus a free flow of water through the valve 48' during discharging the

5 reservoir 28' is provided. The water flow through the valve 48' is not or is essentially not constricted. For manually draining the reservoir 28', the reservoir 28' is extracted from its compartment, whereby the valve 48' is closed. Then the valve 48' may be opened by pushing it by hand or by pushing it against a surface, such that the collected liquid may be drained through the opened valve 48'. By providing several passages 92a-c through the o valve element profile section the counter-flow of air during discharging the reservoir 28' is facilitated, whereby the discharging time for the reservoir 28' is reduced.

Reference Numeral List

2, 2' heat pump tumble dryer 41 drain pipe (condensate collector)

3 casing/ housing 42 drain pump

4 heat pump system 40 44, 44' rinsing/ flushing pump

5 5 base section 46 drain pipe (reservoir compartment)

6 refrigerant loop 48, 48' closing element/ valve

7 input panel 50 spring lever

8 blower 52 elastic sealing element

9 control unit 45 53 elastic sealing element on

1 0 10 first heat exchanger (evaporator) removable reservoir

12 second heat exchanger (condenser) 54, 54' coupling arrangement/ actuating

14 compressor element

15 loading door 56 supply line inlet/ stub

16 expansion device 50 57 supply line outlet/ nozzle

15 17 drum motor 58 flushing duct

18 drum (laundry compartment) 60 rear wall/ rear frame

19 laundry 62 first compartment

20 process air channel 64 second compartment

20a battery channel 55 66 separation wall

2 o 20b rear channel 68a-c liquid passage/ pin hole

20c rising channel 70a-e filter element

20d front channel 72a-b liquid level detector/ sensor

22 fluff filter 74 supporting structure (flushing

24 cooling air blower unit 60 pump)

25 26 condensate collector/ basement 80 movable valve element

tank 82 valve body

27 condensate reservoir front 84 first sealing surface

28, 28' condensate reservoir/ drawer 86 second sealing surface

29 reservoir outlet 65 88 spring element

3 0 30 reservoir compartment 90a-c gasket

31 reservoir compartment outlet/ pipe 92a-c passage

socket 94 body pipe section

32, 32' supply line 96 element pipe section

34, 34' rising portion 70 98a-b locking hook

35 36 communicating portion A process air flow

38 descending portion B refrigerant flow

40 filter element R refrigerant

Claims

Claims:

1. Laundry treatment apparatus adapted for laundry drying, in particular condenser- type laundry dryer, exhaust-type laundry dryer, heat pump dryer or washing machine having drying function, the laundry treatment apparatus comprising:

an apparatus body (3),

a laundry storing compartment (18) for receiving laundry to be dried by passing process air through the laundry storing compartment,

a downstream channel (20d) for guiding the process air exhausted from the laundry storing compartment outside the storing compartment and within the apparatus body,

an apparatus component arranged at and/or within the downstream channel, wherein the apparatus component is exposed to fluff conveyed in the downstream channel (20d),

a cleaning arrangement adapted to clean the apparatus component from fluff by applying liquid in a cleaning cycle,

a collector tank (26) adapted to collect the liquid used for cleaning the apparatus component,

a liquid level detector (72a-b) adapted to detect the liquid level in the collector tank, and

a control unit (9) receiving the signal from the liquid level detector,

characterized in that

the control unit (9) is adapted to monitor and process the signal from the liquid level detector (72a-b) for determining the flow rate and/or the amount of liquid supplied during the cleaning cycle to the apparatus component to be cleaned.

2. Laundry treatment apparatus according to claim 1, further comprising a liquid reservoir (28) for storing liquid to be supplied to the cleaning arrangement for cleaning.

3. Laundry treatment apparatus according to claim 1 or 2, wherein the cleaning arrangement further comprises a valve (48) or a pump (44) operating under the control of the control unit (9) for starting and stopping or dosing the liquid supply to the cleaning arrangement.

4. Laundry treatment apparatus according to claim 1, 2 or 3, wherein the control unit 5 (9) is adapted to

activate component cleaning by activating the cleaning arrangement, and in response thereto to monitor the signal status of the liquid level detector (72a-b).

5. Laundry treatment apparatus according to any of the previous claims, further o comprising a draining pump (42) associated with the collector tank (26) adapted to pump liquid collected in the collector tank (26) to one or more of the following:

a or the liquid reservoir (28) for supplying liquid to the cleaning arrangement, a removable condensate reservoir, and

an external drain line for draining the pumped liquid to the outside of the apparatus5 body, and

wherein the control unit (9) is adapted to operate the draining pump (42) such that the liquid within the collector tank (26) has a reproducible or predefined starting level before activating the cleaning arrangement. 0

6. Laundry treatment apparatus according to any of the previous claims, wherein the liquid level detector (72a-b) is adapted to detect at least two different liquid levels or is adapted to detect a range of different liquid levels in the collector tank.

7. Laundry treatment apparatus according to any of the previous claims, wherein the 5 control unit (9) is further adapted

to monitor the signal of the liquid level detector (72a), and

in dependency of the signal of the liquid level detector (72a) to activate a or the draining pump (42, 44) associated with the collector tank adapted to drain liquid out of the collector tank.

0

8. Laundry treatment apparatus according to any of the previous claims, wherein the control unit (9) is adapted to determine the flow rate and/or liquid amount by monitoring and processing the liquid level variations over time and/or the time intervals of liquid level variations.

5

9. Laundry treatment apparatus according to any of the previous claims, wherein the apparatus component to be cleaned is one or more of: a heat exchanger (10) for dehumidifying the process air after passing the laundry storing compartment by condensing humidity from the process air,

a process air filter (70e) for filtering process air from fluff,

a heat exchanging surface,

5 a process air channel surface, or

a condensate collector bottom portion.

10. Laundry treatment apparatus according to any of the previous claims, wherein the control unit (9) comprises a time counter, wherein the time counter counts a time from o activating the cleaning arrangement or a predefined time after activating the cleaning

arrangement and a time point when the level sensor (72a-b) outputs a predefined sensor signal or changes its sensor signal.

11. Laundry treatment apparatus according to any of the previous claims, wherein the5 control unit (9) comprises a time counter and the level detector comprises a first level sensor and a second level sensor, wherein the first and second level sensors are arranged at a or the collector tank and wherein the time counter counts a time between a time point when the first level sensor outputs a predefined sensor signal (l_max) or changes its sensor signal and a time point when the second level sensor outputs a predefined sensor signal 0 (lmin) or changes its sensor signal.

12. Laundry treatment apparatus according to any of claims 1 to 10, wherein the level detector comprises a multi-level sensor or an continuous-level sensor and the control unit (9) comprises a time counter, wherein the control unit (9) is adapted to determine the flow 5 rate and/or the liquid amount using the temporal development of the multiple ones of the level signals or of the changing continuous level signal.

13. Laundry treatment apparatus according to any of the previous claims, wherein the level detector (72a-b) comprises one or more REED sensors, floater sensors, capacitive 0 sensors, optical sensors, or conductivity sensors.

14. Laundry treatment apparatus according to any of the previous claims, wherein the collector tank (26) is a condensate sump adapted to collect the condensate formed at the or a heat exchanger (10) and adapted to collect the washing liquid that was supplied to the5 apparatus component in the component cleaning cycle.

15. Laundry treatment apparatus according to any of the previous claims, wherein the detector device (72a-b) or the laundry treatment apparatus has no a level sensor that is assigned to or arranged at or arranged in a fluff filter (70a-d) or is in fluid communication with the filter such as to detect the liquid level within the filter.

16. Laundry treatment apparatus according to any of the previous claims, wherein the control unit (9) is further adapted to process the signal of the level detector (72a-b)

for detecting flushing failures, flushing inefficacy or filter clogging,

to monitor the cleaning arrangement during execution of the cleaning cycle and, in dependency of the monitoring, to initiate a second or more cleaning cycles, or

wherein, in dependency of the processing of the at least one signal, the control unit is further adapted to provide a user signal.

17. Laundry treatment apparatus according to any of the previous claims, wherein the processing of the at least one signal indicates that the flow rate and/or the liquid amount is below a predefined threshold.