EP2406420B1 - Laundry drying unit having a lint screen arranged within a process air circuit and a method for operating said laundry drying unit - Google Patents

Description

The invention relates to a laundry drying device with a fluff filter and a method for operating such a laundry drying device.

There are known tumble dryers in which a cleaning liquid is flushed over the lint filter to remove lint that has been deposited on a lint filter, which liquid detaches the lint from the filter surface and transports it away from the filter. This cleaning liquid consists of condensate water from moisture extracted from a laundry during a drying process. Since the amount of condensate water that is available for rinsing off the fluff from the fluff filter depends on the respective load and setting of the dryer, there can be very different filling levels in a washing container. Due to the different liquid level, a different amount of cleaning liquid for cleaning the fluff runs out of the fluff filter for the same opening time of a valve arranged in a floor of the washing container due to the different water pressure.

After the lint has been removed from the lint filter, the cleaning fluid is also used to transport the lint away from the lint filter to a depot. In this depot, the fluff and the condensate water are separated again by filtration. During cleaning, the lint volume already deposited from previous cleaning operations and, for a short time, the lint-laden liquid from the cleaning operation that has just been carried out must be accommodated in the depot. A backwater can form in the depot, which can even lead to an overflow of the lint-laden liquid from the depot.

the WO 2008/119611 A1 describes a method and a device for cleaning a component, in particular an evaporator of a condenser device, as well as a washing machine or tumble dryer with such a device. To clean a component arranged within a process air circuit of a washing machine or tumble dryer, in particular an evaporator of a condenser device, Condensate water, which is obtained in the process air circuit from the drying of damp laundry and is collected in a condensate water pan, is routed to a rinsing container provided above the evaporator and released as a gush of water to the relevant component when it suddenly opens on the outlet side. To clean the evaporator, the entire amount of condensate water stored in the rinsing tank is discharged, which is why the condensate water pan either has to be very large or there is a risk of the condensate water pan overflowing.

From the DE 37 38 031 A1 is a laundry drying device with a component to be cleaned, in particular arranged within a process air circuit, in the form of a heat exchanger and with an elevated rinsing container, wherein a cleaning liquid can be dispensed from the rinsing container through a controllable valve to the component to be cleaned.

From the DE 10 2005 014 842 A1 discloses a circulating air tumble dryer with a heat pump, which has two heat exchangers arranged in the circulating air, which are to be flooded with water to ensure rapid temperature and pressure equalization before the heat pump is started up. The water can be condensate that has accumulated in a drying process and has been stored in a collection container. From here it can be routed to the heat exchangers via a device for opening and shutting off the water outlet and a distribution device.

From the priority older post-published EP 2 199 455 A2 discloses a laundry drying device with a component to be cleaned arranged within a process air circuit and with a rinsing container provided above the component to be cleaned, in which cleaning liquid can be released from the rinsing container through a controllable valve to the component to be cleaned. A quantity of rinsing liquid required as a function of a predetermined cleaning program is determined, compared with the quantity of rinsing liquid present in the rinsing container and, if the required amount is not reached, the rinsing container is filled with water up to the required amount.

It is the object of the present invention, in a generic laundry drying appliance, to prevent cleaning liquid from overflowing during a cleaning process of a component of the laundry drying appliance to be cleaned and to improve the ability to absorb particles cleaned from the component. For this purpose, a corresponding laundry drying device and a method for its operation are to be specified.

This object is solved according to the features of the respective independent claims. Preferred embodiments can be found in particular in the dependent claims.

The laundry drying appliance is equipped with a component to be cleaned, which is arranged in particular within a process air circuit, and with a rinsing container provided above the component to be cleaned, with a cleaning liquid being able to be dispensed from the rinsing container through a controllable valve to the component to be cleaned and with the valve being on the The basis of an amount of cleaning liquid in the washing container that can be controlled, in particular can be actuated, is such that only an amount of cleaning liquid that is just sufficient for effective cleaning is released.

By knowing at least approximately the amount of cleaning liquid, the valve can be controlled in such a way that during a cleaning process the desired amount of cleaning liquid can be drained from the rinsing container with great accuracy to the component to be cleaned. In particular, an amount of cleaning liquid that is just sufficient for effective cleaning can be dispensed, which means that a collection container (fluff depot, condensate water pan, etc.) downstream of the component to be cleaned can only be filled with the smallest possible amount cleaning liquid is filled. This applies in particular in the event that, before a cleaning process, the washing container is filled with a larger quantity of cleaning liquid than is just sufficient for a cleaning process. This reduces the risk of the collection container overflowing, which can consequently be designed for a larger amount of fluff with the same volume. This results in the further advantage that the control of the opening behavior of the valve as a function of the quantity of cleaning liquid in the washing container allows the washing volume to be made more uniform.

The valve is for its actuation with a control device, in particular central

Control device connected to the laundry drying device. The control device is equipped with logic for calculating the amount of cleaning liquid in the washing container.

The control device can be functionally connected to at least one sensor, with at least one measured value of the at least one sensor being able to serve as an input variable or variables for the calculation. The at least one sensor can include, for example, at least one load sensor, at least one humidity sensor (e.g. for measuring a temperature of process air discharged from a laundry drum), at least one temperature sensor (e.g. for measuring a temperature or a temperature difference in a heat exchanger), etc.

According to one embodiment, the valve can be controllable as a function of a load in the laundry drying appliance. This exploits the fact that the controller of some tumble dryers is already able to recognize the load or load quantity in a laundry drum of the tumble dryer. The amount of condensate that occurs during a drying cycle can be at least roughly predicted from the loading values. From this, in turn, the amount of condensate water that will be in the rinsing tank for cleaning can be determined. With this solution, the amount of cleaning liquid (amount of condensate water, possibly with metered fresh water supplied) can be estimated with sufficient accuracy using a method known in principle, which enables a particularly inexpensive implementation.

An even more precise determination can advantageously be achieved in the event that the valve can be controlled as a function of a predetermined degree of drying or a specific dry state (e.g. iron dry, cupboard dry, etc.). With knowledge of the degree of drying and thus the residual moisture remaining in the laundry, the expected amount of cleaning liquid in the washing container can be corrected accordingly.

A more precise determination can advantageously also be achieved in the event that the valve can be controlled as a function of a preselected type of textile (wool, cotton, etc.). Because even if you know the type of textile and thus the residual moisture remaining in the laundry due to the textile, the expected amount of cleaning liquid in the rinsing container can be corrected.

A more precise determination can alternatively or additionally be achieved in that the valve is advantageously controlled as a function of a drying time. The drying speed is essentially the same regardless of the load and an initial residual moisture content. The amount of liquid already collected in the washing compartment can therefore be directly inferred from the drying time that has already elapsed.

As an alternative or in addition, the valve can be controllable as a function of a measured filling level of the washing container and/or the collecting container. The filling level in the rinsing tank can be determined, for example, using a magnetic float with a read switch cascade, Hall sensor scanning or magnetoresistive sensor scanning, or by direct level scanning, e.g. using capacitive, optical or acoustic sensors.

According to the invention, the valve can be controlled with regard to an opening duration.

In other words, the amount of cleaning liquid provided for the cleaning can be metered in that the opening duration of the valve can be adjusted accordingly. The advantage here is that an opening process can be carried out very easily and quickly by opening the valve completely.

In addition, the valve can be controllable with regard to a flow cross section. In other words, the amount of cleaning liquid provided for the cleaning can be metered in that the flow cross section released by the valve can be adjusted accordingly.

According to a further embodiment, the laundry drying device can have a collecting tank in the form of a condensate water pan, in which condensate water produced in the process air circuit by drying damp laundry can be collected, this condensate water being able to be fed to the rinsing tank as the cleaning liquid. The feed can be implemented, for example, by means of a pump.

It is yet another embodiment that the condensate water pan can be fluidly connected upstream of a lint depot, wherein the lint depot can have a drain equipped with a lint retaining element. The lint retaining element can have a filter, for example. The fluff depot can prevent the condensate water tray and a pump that may be connected to it from becoming clogged.

In order to achieve a compact design, it can be advantageous for the fluff depot to be integrated into the condensate water tray as an antechamber. Then the fluff depot can be viewed as an antechamber of the condensate water tray.

In order to remove the lint conveniently and also without any problems by an end customer, it can be advantageous for the lint depot to be removable.

1. (a) Ermitteln einer Menge der Reinigungsflüssigkeit in dem Spülbehälter und
2. (b) Steuern des Ventils zum Ablassen der Reinigungsflüssigkeit aus dem Spülbehälter an das zu reinigende Bauteil in Abhängigkeit von der ermittelten Menge der Reinigungsflüssigkeit derart, dass nur eine für eine effektive Abreinigung gerade noch ausreichende Menge der Reinigungsflüssigkeit abgegeben wird.

The object is also achieved by a method for operating the laundry drying device described above, the method having at least the following steps:

1. (a) determining a quantity of the cleaning liquid in the rinsing container and
2. (b) controlling the valve for draining the cleaning liquid from the rinsing container to the component to be cleaned depending on the determined amount of cleaning liquid such that only an amount of cleaning liquid just sufficient for effective cleaning is released.

It can be advantageous if, in step (b), the control of the valve includes opening the valve with an opening duration depending on the determined quantity of cleaning liquid.

It can also be advantageous if, in step (b), the control of the valve includes opening the valve with a flow cross section as a function of the determined quantity of cleaning liquid.

It has been found to be advantageous for the valve to be opened until a maximum quantity of approximately 0.5 l to 1 l of the cleaning liquid has been drained to the component to be cleaned. This results in good cleaning performance with low consumption of cleaning fluid at the same time, and there is no risk of the collection container overflowing.

Fig.1

zeigt eine Prinzipskizze eines Wäschetrocknungsgeräts;

Fig.2

zeigt eine Auftragung einer aus einem Spülwasserbehälter des Wäschetrocknungsgeräts aus Fig.1 abgegebenen Reinigungsflüssigkeitsmenge gegen eine in dem Spülbehälter anfänglich gespeicherte Reinigungsflüssigkeitsmenge für verschiedene Öffnungsdauern eines zugehörigen Ventils.

In the following figures, the invention is described schematically in more detail using an exemplary embodiment/examples. For the sake of clarity, elements that are the same or have the same effect can be provided with the same reference symbols.

Fig.1

shows a schematic diagram of a laundry drying device;

Fig.2

shows a plot of a from a rinsing water tank of the laundry drying device Fig.1 Discharged amount of cleaning liquid against an amount of cleaning liquid initially stored in the rinsing container for different opening durations of an associated valve.

1 shows a laundry drying device W, of which, however, only the parts that are helpful for an understanding of the present explanation are shown here. These parts include, above all, a washing or laundry drum WT containing damp laundry to be dried and a process air flow arrangement connected to it, which will be considered in more detail below, through which in the direction of Fig.1 indicated arrows process air flows. The laundry drum WT and the process air flow arrangement together form a process air circuit.

The process air flow arrangement includes a number of process air ducts LU1, LU2, LU3 and LU4 and devices connected to them, namely a blower GB, a heating device HE and an evaporator EV of a condenser device not shown in detail here. The evaporator EV is connected on the outlet side via a funnel-shaped connection TR1 serving as a transition part to one end of the process air duct LU1, to which cold, dry process air is supplied and which is connected at its other end to an input connection of the blower GB. This blower GB is connected on the output side via the process air duct LU2 to the input side of the heating device HE, which is connected on the output side via the process air duct LU3 to the input side of the washing or laundry drum WT for the supply of now hot, dry process air. On the outlet side, the washing or laundry drum WT is for discharging hot, moist process air, which is discharged from moist laundry to be dried in it, through the process air duct LU4 and an adjoining funnel-shaped connection TR2, which also serves as a transition part, to the inlet side of the evaporator EV connected. In this evaporator EV, the moisture in the hot, moist process air supplied through the process air duct LU4 from the washing or laundry drum WT condenses. The resulting condensate water in the evaporator EV occurs, as in Fig.1 indicated, in the form of water droplets into a collecting container arranged below the evaporator EV in the form of a condensate water pan KW, in which it is collected.

The condensate water collected in the condensate water tray KW must be drained out of it so that it does not overflow there. For this purpose, in the present case, the condensate water pan KW is connected by a connecting channel K1 to the input side of an electric pump P1, which can be an impeller pump, for example. On the output side, the pump P1 is connected through a connecting channel K2 to the input side of a first distributor VE1, which in the present case may be a controllable two-way valve. The first distributor in question or the two-way valve VE1 has two outlet connections, one of which is connected to a connecting channel K3 and the other of which is connected to a connecting channel K4.

The connecting channel K3 is used to discharge condensate water pumped up from the condensate water pan KW by the pump P1 into a separate storage tank SP1 provided in the upper area of the washing machine or tumble dryer containing the device according to the invention. This storage container SP1 can be, for example, a storage container that can be removed manually from the washing machine or tumble dryer in which the device described is contained, through which the condensate water pumped up into it from the condensate water pan KW can be disposed of.

The connecting channel K4 is used on the outlet side to release condensate water fed to it from the first distributor or two-way valve VE1 to a rinsing tank SB1. This rinsing container SB1, which is arranged as far as possible on the upper side of the washing machine or tumble dryer containing the device shown and which can have the same storage capacity as the condensate water pan KW or the storage container SP1, for example for holding 2 liters of condensate water, is to be on the safe side - as shown - provided with an overflow arrangement, through which condensate water that may overflow from the rinsing tank SB1 reaches an overflow tank UB, which is directly connected to the condensate water pan KW through a return channel RK and is able to deliver condensate water that has entered it directly to the condensate water pan KW.

On the other hand, the condensate water collected in the condensate water pan KW can be pumped through a connection channel K5 by means of an electric pump P2, which can also be an impeller pump, for example, into a connection channel K6, which can lead to a waste water disposal arrangement, such as a water drain line .

The rinsing tank SB1 is connected to a downpipe FR by its outlet side via a normally closed first valve VT1, which can be opened by actuation or control. A distributor VE2 is inserted in the downpipe FR, the input side of which is connected to the flushing tank SB1. In the present case, the distributor VE2 is a controllable two-way valve. At the distributor VE2, the downpipe FR starts from a non-branched section FRa divided into a first branch FRb and a second branch FRc. The first branch FRb leads to an inlet area of the evaporator EV, while the second branch FRc leads to the process air duct LU4. More precisely, the second branch FRc leads to an upper edge of an air-permeable fluff filter FS used in the process air duct LU4, which is used to remove fluff and other particles from the moist, warm process air.

In the following, the mode of operation of the downpipe FR for cleaning the evaporator EV is first described, i.e. the non-branched part FRa between the first valve VT1 and the second distributor VE2 and the first branch FRb: In this regard, the downpipe FR, which has a relatively large cross section, preferably has a Drop height of about 500 mm to 600 mm for the condensate water to be discharged in surges from the rinsing tank SB1. The downpipe FR or its first branch FRb is at its in Fig.1 lower end is provided with a stationary flushing nozzle DU, which has an approximately oval-shaped outlet area with a width of approximately 6 mm to 10 mm and extends over the entire width of the evaporator EV, which is at a fixed distance from the longitudinal center of its outlet area, which here is approximately is 10 mm to 50 mm, from which in Fig.1 right-lying entry area of the evaporator EV for hot, moist process air is arranged. This arrangement of downpipe FR or FRa, FRb and rinsing nozzle DU allows condensate water escaping from the rinsing tank SB1 when the first valve VT1 is open to be discharged as a gush of water to an evaporator area that is preferably located only at the defined distance from the entry area of the process air into the evaporator EV. The dimensions of the passage opening of the first valve VT1 and the cross section of the downpipe FR or FRa, FRb and the flushing nozzle DU are preferably selected in such a way that the condensate water collected in the flushing tank SB1 - i.e. around 2 liters of condensate water according to the example assumed above - within a very short period of time of 1 to 2 seconds as a gush of water to the evaporator EV. By dispensing such a gush of water, i.e. at a speed of, for example, up to 0.5 liters to 2 liters in 2 seconds and preferably immediately after the damp laundry has been dried, which is in the washing or laundry drum WT for drying, it is possible in a particularly effective manner from the aforementioned process air entry area of the evaporator EV and via this area to flush away fluff and other contaminants that have been supplied there through the process air duct LU4 and the funnel-shaped connection TR2. In order to achieve a largely uniform delivery quantity of the water gush between the beginning and the end of its delivery to the evaporator EV, it has proven to be expedient if the downpipe FR, FRb has an area that also includes the flushing nozzle DU, which is based on the cross section of the outlet area of the washing container SB1 is narrowed. However, it must be ensured that the previously specified minimum amount of condensate water per unit of time is provided for flushing the evaporator EV. In addition to the above-mentioned gush-type delivery of the condensate water contained in the rinsing tank SB1 to the evaporator EV, normal, pressurized tap water can be delivered to the evaporator for cleaning. For this purpose, a water inlet pipe WA is provided, to which the pressurized tap water in question is fed. With the delivery side of the relevant water supply pipe WA is in accordance Fig.1 a second valve VT2 connected, which can be, for example, a normal shut-off valve. A water discharge pipe ZR is provided on the outlet side of the second valve VT2, which protrudes into the downpipe FR in the lower area thereof, ie according to FIG Fig.1 above the flushing nozzle DU of the relevant downpipe FR or FRb. In this way, the mains water can be released to clean the evaporator EV in addition to the condensate water discharged in a surge from the rinsing container SB1, or it can also be released solely to the evaporator EV for its cleaning. In order to prevent the condensate water pan KW from overflowing, the condensate water collected in the rinsing tank SB1 can be pumped out with the aid of the pumps P1 and P2 mentioned. It is clear here that the pump P1 only has to pump off a portion of the condensate water collected in the condensate water pan KW that corresponds to the capacity of the rinsing tank SB1 and/or the storage tank SP1. The excess amount of condensate water, which is discharged to the condensate water pan KW, is to be pumped out into the aforementioned drain arrangement using pump P2. As a result of this particular additional delivery of tap water for cleaning the evaporator EV, the latter can be cleaned very well. The discharge of tap water in question for cleaning the evaporator EV is of particular importance in particular in the case of a washer-dryer which already has a tap water inlet device and a tap water outlet device.

A combined discharge of pressurized tap water and the condensate water discharged in surges from the rinsing tank SB1 achieves an even more efficient cleaning of the evaporator EV than by the sole discharge of tap water or condensate water to this evaporator EV. In the Fig.1 On the other hand, the device shown can also be used in a tumble dryer, in which only damp laundry is to be dried. In this case, the tumble dryer in question - which normally does not need connections to a water inlet and a water outlet - can be supplied with mains water in the water inlet pipe WA, i.e. it can be connected to a corresponding mains water connection, then the connecting channel K6 must be connected to a waste water discharge arrangement. With regard to the cleaning of the evaporator EV with condensate water from the rinsing tank SB1 and possibly tap water, the same conditions then apply in a tumble dryer as have been explained above in connection with a washer-dryer.

In the embodiment shown, a fluff depot FD is fluidically connected upstream of the condensate water pan KW. The fluff depot FD has a drain (not shown) through which the condensate water introduced into the fluff depot FD can continue to run into the condensate water tray KW. The outlet has a lint retaining element in the form of a lint filter (not shown), through which lint is retained in the lint depot FD. This prevents the pumps P1 and P2 from clogging with the fluff. The fluff depot FD is integrated into the condensate water pan KW and thus serves as an antechamber for the condensate water pan KW as such. The lint depot FD can be removed for easy removal of the lint that has settled in the lint depot FD.

The mode of operation of the downpipe FR for cleaning the fluff filter FS will now be described, i.e. the non-branched part FRa and the second branch FRc: By opening the first valve VT1, condensate water is now in a corresponding position of the distributor VE2 from the flushing tank SB1 through the non-branched one Part FRa and further passed through the second branch FRc to the fluff filter FS. The condensate water then flows from top to bottom over the fluff filter FS and, with the flow, carries away fluff and other particles that have accumulated on the fluff filter FS during a drying process. Then the fluff Condensate water containing runs through a further connection channel K7 to the fluff depot FD and from there to the condensate pan KW. However, the 2 l volume of condensate used to clean the evaporator EV is not required to clean the fluff filter FS. Rather, with large amounts of water (more than 0.5 l) and with a large amount of lint deposited in the lint depot, it can happen that the lint depot FD can no longer absorb the amount of liquid generated during cleaning within a short time. This causes the lint depot FD to overflow and consequently condensate water containing lint to be disadvantageously distributed into the condensate water pan KW. In order to be able to accommodate as much fluff from as many cleaning processes as possible, in particular of the fluff filter, in the depot, the amount of liquid for a cleaning process should not be too large. For this reason, when the fluff filter FS is cleaned, the first valve VT1 is actuated in such a way that only approximately 0.5 l to 1 l of the cleaning liquid is drained. For this purpose, the first valve VT1 can be opened with an opening duration depending on the amount of cleaning liquid in the washing container SB, which allows approximately 0.5 l to 1 l of the cleaning liquid to pass through. The flush volume of 0.5 l makes it possible, for example, to store a quantity of fluff (compacted when wet) for approx. 50 drying cycles in the fluff depot. The amount of cleaning liquid is estimated from a load on the laundry drum WT.

For the assessment, the laundry drying device W is equipped with a load sensor BS on the laundry drum WT, which essentially senses the weight of the laundry in the laundry drum WT, specifically at the beginning of a drying cycle in particular. Optionally, additional information about an initial moisture level of the laundry, a desired degree of drying of the laundry, the duration of the drying process that has already elapsed, measured moisture values of the process air and/or measured temperature values on a heat exchanger can be taken into account for this estimation. Alternatively, at least one filling level sensor could be attached to the rinsing container and/or to the condensate water pan KW.

First, for example by means of a control device ST described in more detail below, the quantity of cleaning liquid in the washing compartment SB taking into account at least one measured value sensed by the loading sensor BE and/or a already past drying time determined. Then the first valve VT1 for draining the cleaning liquid from the rinsing tank to the component to be cleaned is controlled or switched depending on the determined quantity of the cleaning liquid. A relationship between the quantity of cleaning liquid stored in the washing container and an opening behavior of the first valve VT1 (eg an opening duration) can be stored in the control unit ST, for example via a family of characteristics. The family of characteristics can, for example, have a characteristic curve which establishes a relationship between a load and/or a filling level in the washing container SB on the one hand and an opening duration and/or a flow cross section of the first valve VT1 on the other. The flow cross section can be set, for example, via an opening height of the first valve VT1. To clean the fluff filter FS, the control device ST can also switch the distributor VE2 to the fluff filter FS.

To control the in Fig.1 illustrated various devices as have been mentioned above, the control device ST is provided. This control device ST can include, for example, a microcontroller with its own software or a microprocessor controller with a CPU, a ROM memory containing an operating program and a work program, and a working memory RAM, as well as interface circuits, to which actuation signals are supplied on the input side and which on the output side control signals are sent to the various devices in Fig.1 allow the device shown to be released.

The control device ST has according to Fig.1 For example, two input terminals E1 and E2, with which switches S1 and S2 are connected, which are each connected to a voltage terminal U, which may carry a voltage of +5V, for example. On the output side, in the present case the control device ST has, for example, nine output connections A0, A1, A2, A3, A4a, A4b, A5, A6 and A7, as well as an input connection A8 shown as an example.

The output connection A0 is connected to a control input of the pump P2, through the operation of which the condensate water collected in the condensate water pan KW can be pumped through the connecting channels K5 and K6 to a waste water receiving device, such as a drain pipe.

The output connection A1 of the control device ST is connected to a control input of the blower GB, which can be switched on or off by control signals supplied to it at this control input.

The output connection A2 of the control device ST is connected to a corresponding control input of the heating device HE, which can be switched on or off by control signals supplied to this control input.

The output connection A3 of the control device ST is connected to the washing or laundry drum WT via a connection which is only to be understood as an operative connection, and which can be rotated or stopped via control signals emitted via the relevant connection. This means that the relevant control signals are output from the output connection A3 of the control device ST to an electric drive motor connected to the washing or laundry drum WT.

The output port A4a of the control device ST is connected to an actuation input of the second valve VT2, which is either closed or fully opened by control signals supplied to it from the output port A4a of the control device ST. However, it is also possible that the second valve VT2, which, as mentioned above, is preferably an electrically actuated shut-off valve, is normally closed and only activated by a control signal emitted by the output connection A4a of the control device ST (e.g. corresponding to a binary signal "1") can be fully opened.

The output connection A4b of the control device ST is connected to an actuation input of the first valve VT1, which is either closed or fully opened by control signals supplied to it from the output connection A4b of the control device ST. However, it is also possible for the first valve VT1 to be normally closed and only to be fully opened by a control signal (eg corresponding to a binary signal "1") emitted by the output connection A4b of the control device ST.

The output connection A5 of the control device ST is connected to a control or actuation input of the first distributor or two-way valve VE1. Control signals sent via this connection to the first valve or two-way valve VE1 allow the relevant first valve or two-way valve VE1 to deliver condensate water supplied to it from the condensate water pan KW by means of the pump P1 either to the connecting duct K3 or to the connecting duct K4 or such a delivery to block both connecting channels K3 and K4.

The output connection A6 of the control device ST is connected to a control input of the mentioned pump P1, which can either be started for a pumping process or stopped on the basis of control signals fed to it through this connection.

The output connection A7 of the control device ST is connected to a control or actuation input of the second distributor VE2. Control signals sent to the valve VE2 via this connection allow the relevant valve VE2 to deliver cleaning fluid drained from the washing container SB1 either into the first branch FRb or into the second branch FRc of the downpipe FR.

An output connection of a loading sensor BS is connected to an input connection A8 of the control device ST, so that the control device ST can sense measured values of the loading sensor BS for determining an amount of rinsing water in the rinsing water tank.

With regard to the control device ST considered above with its input connections E1 and E2 and output connections A0 to A7, it should also be noted that by closing the switch S1 connected to the input connection E1 of the control device ST, for example, the normal drying operation of in the washing or laundry drum WT located damp laundry is introduced and carried out and that by closing the switch S2 connected to the input connection E2 of the control device ST the delivery of condensate water from the abruptly opened washing container SB1 is controlled as a surge of water to the evaporator EV. The two switches S1 and S2 can only be actuated in such a way that only one of the two Switches S1 and S2 can be actuated. The relevant switches S1 and S2 can, moreover, each be formed by a pushbutton switch.

The provision of the condensate water in the rinsing tank SB1 from the condensate water pan KW can, for example, take place under program control, preferably during a drying operation or after its completion automatically or specifically by manual intervention in the program control of the washing machine or tumble dryer containing the device described. In the case of such a manual intervention in the program control, the control device ST could be connected to the voltage connection U via a further input via a further switch (not shown).

This cleaning process can optionally be repeated once or several times with the relevant condensate water. For this purpose, the condensate water collected again in the condensate water pan KW must then be pumped up into the rinsing tank SB1, from which it is then delivered again in a surge to the evaporator. After completing the cleaning or cleaning process, the condensate water collected in the condensate water tray KW must either be drained into an existing sewage system or pumped into the rinsing tank SB2, which must then be emptied manually.

In addition to the cleaning process considered above, such a cleaning process and thus cleaning of the evaporator EV can be carried out using pressurized tap water, which is fed to the relevant evaporator EV via the water inlet pipe WA, the second valve VT2 and the water outlet pipe ZR. In this case, as an alternative or in addition to the delivery of a control signal that opens the valve VT1, the control device ST delivers a corresponding control signal to the second valve VT2 to open it.

Fig.2 shows a plot of an open valve VT1 from the flushing water tank SB Fig.1 delivered quantity of cleaning fluid (here quantified as a flushing volume Vsp) in ml against a quantity of cleaning fluid stored in the flushing tank SB before a cleaning process (here quantified as a storage volume Vb) in ml for different opening durations t of the valve VT1.

The plot shows that due to the different pressure of the flushing water column with different storage volume Vb, there is a significant dependency of the flushing volume Vsp on the storage volume Vd (e.g. derivable from the fill level). For example, with an opening duration of the valve VT1 of t = 2000 ms (2 s) with a storage volume Vd of 2000 ml (2 l), a flushing volume Vsp of approx. 1350 ml runs off, but with a storage volume Vd of 1000 ml only one Flushing volume Vsp of approx. 750 ml. Flushing volume Vsp can be equalized here to about 550 ml by opening duration tSt=tSt(Vd) of valve VT1 (dashed curve) depending on storage volume Vd. In particular, the opening duration tSt can be shorter the larger the storage volume Vd is.

Of course, the present invention is not limited to the embodiment shown.

That's how it is Fig.1 The arrangement shown is only functionally sketched and does not need to reflect any real dimensions or spatial arrangements, for example. For example, the sections FRa, FRc of the downpipe FR leading from the rinsing container SB1 to the lint filter FS can be arranged so that they fall continuously, i.e. have neither a right angle to one another nor a horizontal section, whereby a sufficient flow rate can be maintained at the lint filter FS. The position of the fluff filter FS is also not limited to a vertical section of the process air duct LU4, or to the process air duct LU4 as such.

Furthermore, a fresh water supply can also be set up for the washing compartment in order to achieve a minimum amount of washing water if the fill level in the washing compartment falls below an amount required for adequate cleaning.

The valve VT1 and the distributor VE2 of the downpipe can also be designed as a single valve, so that the downpipe to the evaporator and the feed line to the fluff filter are fluidically separated.

In general, no other component of the laundry drying device apart from the fluff filter needs to be cleaned by condensate water or the device shown. For example, a laundry drying device can be provided which no longer provides for cleaning of the evaporator, since the fluff is already caught by the fluff filter to an extent sufficient for long-term operation.

Furthermore, instead of the second pump P2, another two-way valve could be arranged behind the pump P1 and in front of the two-way valve VE1, which alternatively directs the condensate water K to the two-way valve VE1 or to a sewage disposal system.

Reference List

A0, A1,A2, A3

output connections

A4a, A4b, A5, A6 BS

load sensor

E1, E2

input connections

EV

Evaporator

FD

lint depot

FR

downpipe

Mrs

Unbranched part of the downpipe

FRb, FRc

Branching part of the downpipe

FS

fluff filter

GB

fan

HE

heating device

K1, K2, K3, K4, K5, K6, K7

connecting channels

week

condensate water pan

LU1, LU2, LU3, LU4

process air ducts

P1, P2

pump

RK

return channel

S1, S2

counter

SB1

flush tank

SO

pestle

SP1

storage tank

ST

control device

T

opening time

TE

locking plate

TR1, TR2

funnel-shaped connections (transition parts)

u

voltage connection

UB

overflow tank

Vd

storage volume

VE1, VE2

distributor

VT1, VT2

Valve

vs

purge volume

WA

water inlet pipe

WT

laundry drum

W

laundry drying machine

ZR

water supply pipe

Claims (14)

1. Laundry-drying appliance (W) having a component (EV; FS) requiring to be cleaned located inside a process-air circuit and having a washing tank (SB) provided above the component (EV; FS) requiring to be cleaned, wherein an amount of cleaning fluid provided for cleaning can be dispensed from the washing tank (SB) through a controllable valve (VT1) onto the component (EV; FS) requiring to be cleaned, wherein the amount of cleaning fluid can be dosed so that the opening duration of the valve can be set, and wherein the opening duration of the valve (VT1) can be controlled as a function of an amount of cleaning fluid located in the washing tank (SB), wherein for its actuation the valve (VT1) is connected to a control device (ST) of the laundry-drying appliance (W), and wherein the control device (ST) is equipped with a logic for calculating an amount of cleaning fluid located in the washing tank (SB).
2. Laundry-drying appliance (W) according to claim 1, wherein the valve (VT1) is controllable as a function of a load of the laundry-drying appliance (W).
3. Laundry-drying appliance (W) according to claim 2, wherein the valve (VT1) is controllable as a function of a set drying level of the laundry-drying appliance (W).
4. Laundry-drying appliance (W) according to one of the preceding claims, wherein the valve (VT1) is controllable as a function of a drying time.
5. Laundry-drying appliance (W) according to one of the preceding claims, wherein the valve (VT1) is controllable as a function of a fill-level height of the washing tank (SB).
6. Laundry-drying appliance (W) according to one of the preceding claims, wherein the valve (VT1) is controllable in terms of a flow cross-section.
7. Laundry-drying appliance (W) according to one of the preceding claims, having a condensate-water tray (KW) in which condensate water arising in the process-air circuit from drying damp laundry can be collected, wherein this condensate water can be ducted to the washing tank (SB) as the cleaning fluid.
8. Laundry-drying appliance according to claim 7, wherein a lint repository (FD) is located fluidically upstream of the condensate-water tray (KW), wherein the lint repository (FD) has a drain fitted with a lint-retaining element.
9. Laundry-drying appliance (W) according to claim 8, wherein the lint repository (FD) is integrated in the condensate-water tray (KW).
10. Laundry-drying appliance according to one of claims 8 or 9, wherein the lint repository (FD) is detachable.
11. Laundry-drying appliance (W) according to one of the preceding claims, wherein the control device (ST) is functionally connected to at least one sensor (BS), wherein it is possible for at least one measured value of the at least one sensor (BS) to serve as an input quantity for performing the calculation of the amount of the cleaning fluid.
12. Method for operating the laundry-drying appliance (W) according to one of the preceding claims, wherein the method has at least the following steps:

    (a) Ascertaining an amount of the cleaning fluid in the washing tank (SB); and

    (b) as a function of the ascertained amount of cleaning fluid, controlling the valve (VT1) for releasing the cleaning fluid from the washing tank (SB) onto the component (EV; FS) requiring to be cleaned, wherein controlling the valve (VT1) includes opening the valve (VT1) for an opening duration that is a function of the ascertained amount of cleaning fluid.
13. Method according to claim 12, wherein at step (b), controlling the valve (VT1) includes opening the valve (VT1) having a flow cross-section as a function of the ascertained amount of cleaning fluid.
14. Method according to one of claims 12 or 13, wherein the valve (VT1) will be kept open until up to approximately 0.5 to 1 l of the cleaning fluid has been released onto the component (EV; FS) requiring to be cleaned.

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