EP3135802A1 - Household appliance with cleaning device for heat exchanger - Google Patents

Abstract

A household appliance 1 has a fan 7 for moving air in an air flow channel 3 in a flow direction, a first heat exchanger 4 and a second heat exchanger 6, which are arranged in the air flow channel 3 with respect to the flow direction one behind the other, a cleaning device 5 for cleaning the first Heat exchanger 4 with cleaning liquid W, wherein at operated cleaning device 5 and operated fan 7 at least a portion of the cleaning liquid W is directed to the second heat exchanger 6, and a collecting container 11 for dripping of the second heat exchanger 6 cleaning liquid W, the fan 7 dependent from a level L of the collecting container 11 is operable. A method is used to operate a household appliance 1, wherein the fan 7 is operated depending on a level L of the collecting container 11. The invention is particularly advantageously applicable to laundry drying equipment, in particular to circulating air laundry drying equipment. The invention is particularly advantageous applicable to household appliances with heat pump.

Description

The invention relates to a household appliance, comprising a fan for moving air in an air flow channel in a flow direction, a first heat exchanger and a second heat exchanger, which are arranged in the air flow passage in succession with respect to the flow direction, a cleaning device for cleaning the first heat exchanger with cleaning liquid wherein at operated cleaning device and operated fan at least a portion of the cleaning liquid can be directed to the second heat exchanger, and a collecting container for dripping of the second heat exchanger cleaning liquid. The invention also relates to a method for operating a household appliance with a fan for moving air in an air flow channel in a flow direction, with a first heat exchanger and a second heat exchanger, which are arranged in the air flow channel with respect to the flow direction behind one another, with a cleaning device for Cleaning the first heat exchanger with cleaning liquid, wherein at operated cleaning device and operated fan at least a portion of the cleaning liquid can be directed to the second heat exchanger, and with a collecting container for dripping of the second heat exchanger cleaning liquid. The invention is particularly advantageously applicable to laundry drying equipment, in particular to circulating air laundry drying equipment. The invention is particularly advantageous applicable to household appliances with heat pump.

Fig.1 shows a sketch of a heat pump tumble dryer 1 of the type in question. This has a receiving space for laundry to be dried (o. Fig.), Here, for example, a horizontally rotatable laundry drum 2. In a drying process penetrates dry-warm process air P from a process air duct 3 as the air flow channel in the laundry drum 2 and sweeps over the laundry there. The process air P absorbs moisture. The now moist-warm process air P exits the laundry drum 2 again and is guided through the process air duct 3 to a first heat exchanger 4. The first heat exchanger 4 cools the process air P, which condenses out. A heat exchanger surface of the first heat exchanger 4 located in the process air duct 3 is covered by a moisture film from which drops of condensation water fall off and fall down, for example into a drip tray (not shown). Of the Moisture film but also in the process air P located particles such as lint and hair on the heat exchanger surface, which remain there even after evaporation of the moisture film and can reduce the effectiveness of the first heat exchanger 4. In order to remove the lint, hair, etc. from the first heat exchanger 4, a cleaning device 5 may be used which cleans the heat exchanger surface of the first heat exchanger 4 with water W at high momentum as a cleaning agent. The cleaning device 5 may, for example, have a nozzle in communication with a pump, which is directed onto the first heat exchanger 4. Alternatively, the cleaning device 5 may have a downpipe communicating with a water reservoir that is to be opened in a targeted manner (not shown), so that water W discharged in the downpipe at high speed impinges on the first heat exchanger 4 from above. The downpipe may be formed on the output side with a nozzle system to produce a wider water curtain.

From the first heat exchanger 4, the now drier process air P is led to a second heat exchanger 6, which heats the process air P again. The first heat exchanger 4 and the second heat exchanger 6, so are arranged one behind the other in relation to the flow direction of the process air P.

From the second heat exchanger 6, the now dry-warm process air P is introduced through the process air duct 3 into the laundry drum 2. The process air duct 3 thus forms a closed process air circuit with the laundry drum 2. For circulating the process air P in the process air circuit, a fan or fan 7 may be provided. From the perspective of the process air P, the first heat exchanger 4 acts as a condenser and the second heat exchanger 6 acts as a heater.

The first heat exchanger 4 and the second heat exchanger 6 are formed here as parts of a heat pump, which additionally has a drive in the form of a compressor 8 and an expansion valve 9. These components 4, 6, 8 and 9 are interconnected in the arrangement shown by refrigerant tubes 10 in which working fluid or refrigerant K circulates. The operation of a heat pump is basically well known and need not be further elaborated here. The first heat exchanger 4 serves as an evaporator and the second heat exchanger 6 as a condenser from the perspective of the heat pump.

Although the lint and hair settle predominantly on the moist first heat exchanger 4, but to a small extent also on the second heat exchanger 6. In order to clean the second heat exchanger 6, the cleaning device 5 is operated with the fan 7 running. As a result, water W (eg in the form of a water curtain), which is located in the process air P in the region of the first heat exchanger 4, partially (eg to about 50%) entrained with the process air P and reaches the second heat exchanger 6. This is cleaned in the area of the impinging water W.

The water W coming to the second heat exchanger 6 drips down therefrom into an e.g. upwardly open collecting container 11, which can also be referred to as a "boat". The drainage of the water W from the collecting container 11 through a drain (not shown) can take place very slowly. Therefore, when cleaning the second heat exchanger 6 different error mechanisms occur: a) The amount of water used for rinsing the second heat exchanger 6 ("Spülwassermenge" Vspül) is significantly greater than a volume of the collecting container 1, whereby it exceeds a maximum level Lmax to overflow Water W can come into the process air duct 3. This introduction of water W in the process air duct 3 and thus also in the process air P is not desirable, since a rewetting of the laundry can take place. This, in turn, can lead to uneven drying results, deterioration of equipment performance or contamination on the laundry.

The second heat exchanger 6 may be arranged in a variant at least partially in the collecting container 11. As a result, the second heat exchanger 6 can at least partially be in the water W with increasing fill level L in the collecting container 11 in order to further improve a cleaning performance. In another variant, the second heat exchanger 6 is not in the collecting container 11th

In principle, the second heat exchanger 6 can be cleaned in a process independent of a process for cleaning the first heat exchanger 4. For example, to clean the second heat exchanger 6, the fan 7 can be operated and not operated to clean the first heat exchanger. The cleaning of the second heat exchanger 6 can during a drying process or be carried out in a separate cleaning process. For example, during operation of the fan 7, approximately 50% of the water W directed onto the first heat exchanger 4 can be transferred or forwarded to the second heat exchanger 6.

A position of the fan 7 in the process air duct 3 is basically not limited. Thus, the fan 7 except between the laundry drum 2 and the first heat exchanger 4, for example, between the second heat exchanger 6 and the laundry drum 2 may be arranged.

The operation of the fan 7 and the cleaning device 5 can be controlled by means of a control device 12.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art and in particular to provide an improved possibility for cleaning the second heat exchanger.

This object is achieved according to the features of the independent claims. Preferred embodiments are in particular the dependent claims and the following description and attached drawing removable.

The object is accordingly achieved by a household appliance, comprising a fan for moving air in an air flow channel in a flow direction, a first heat exchanger and a second heat exchanger, which are arranged one behind the other in the air flow channel with respect to the flow direction, a cleaning device for cleaning the first Heat exchanger with cleaning liquid, wherein at operated cleaning device and operated fan at least a portion of the cleaning liquid can be directed to the second heat exchanger, and a collecting container for dripping from the second heat exchanger cleaning liquid, wherein the fan is operable depending on a level of the collecting container.

This household appliance has the advantage that a carryover of cleaning liquid of the collecting container by the process air can thus be avoided in a simple manner and without a constructive redesign of existing household appliances.

It is an embodiment that the heat pump domestic appliance is a laundry drying apparatus and the air flow channel is a process air channel. This allows a particularly effective cleaning. The clothes dryer may be a standalone tumble dryer or a washer dryer. The process air duct can be a closed process air duct ("circulating air dryer") or an open process air duct ("exhaust air dryer").

It is still an embodiment that the household appliance has a heat pump, the first heat exchanger corresponds to an evaporator of the heat pump and the second heat exchanger corresponds to a condenser of the heat pump.

The cleaning device may, for example, have a nozzle that can be pressurized with the cleaning fluid or a downpipe.

The cleaning fluid may be or have water. The cleaning fluid may include or be fresh water and / or condensate. The water may have additives, for example detergents.

The level corresponds to a corresponding volume of the cleaning agent in the collecting container, so that the object is also achieved in that the fan is operable depending on a volume of the cleaning agent present in the collecting container.

It is an embodiment that the fan is sustainable depending on the level of the collecting container. This can be achieved, for example, by a controlled stopping of a motor of the fan (hereinafter referred to as "process air motor" without limiting the generality). As a result, the amount of cleaning fluid reaching the second heat exchanger can be set particularly easily, in particular reduced. This can be done via a simple adaptation of a flushing duration tspül the second heat exchanger, which depends on a corresponding operation of the fan. The associated flushing water quantity Vspül can be calculated in accordance with Vspül = (dV / dt) x tspül, whereby (dV / dt) corresponds to an amount of cleaning liquid dV or a flushing rate arriving at the second heat exchanger per unit time dt. As a result, a flushing time required for achieving the flushing water quantity Vspül can be flushed tspül = Vspül / (dV / dt) can be determined. If an overflow of the collecting container is to be avoided, then the flushing duration tspül should not exceed a maximum collecting volume Vmax of the collecting container, ie tspül <Vmax / (dV / dt) should apply. An outflow rate (dVout / dt) from the catch tank can be taken into account by replacing dV / dt with (dV / dt - dVout / dt). The shutdown of the process air motor can be limited in time.

It is still an embodiment that the fan is stalwart before an end of an operation of the cleaning device. This is particularly advantageous when a downpipe for flushing or cleaning of the first heat exchanger is used, since the operating time is advantageously fixed by opening and closing a valve connected to a high water tank valve. A lower opening time of the valve would possibly be disadvantageously associated with a lower water pressure during cleaning. Also, there is the further advantage that in the period between stopping the fan and the end of the operation of the cleaning device, the first heat exchanger is cleaned.

Alternatively or additionally, the fan can be activated or started after a start of operation of the cleaning device. The fan may be stopped or stopped from, with, or after completion of a dispensing of cleaning fluid from the purifier.

In principle, however, the operating time of the cleaning device can be adjusted to a desired operating period of the fan, in particular when using a cleaning device driven by a pump.

Alternatively or in addition to a duration of operation of the fan, a ventilation performance or speed of the fan for adjusting the amount of flushing water Vspül conducted to the second heat exchanger can be varied, ie, dV / dt can be selectively varied or adjusted.

It is a further embodiment that the fan is sustainable depending on a measured level of the collecting container. Thus, a particularly accurate filling of the collecting container can be achieved. For this purpose, the household appliance may be formed with at least one level sensor, e.g. a float with Hall sensor. In particular, an influence of an altered runoff behavior can be taken into account.

It is yet another embodiment that the fan is sustainable depending on a calculated level of the collection container. This embodiment is particularly inexpensive because it does not require a level sensor. Thereby, e.g. a predetermined purge rate dV / dt is used.

It is also an embodiment that the fan is sustainable upon reaching a shutdown level of the collection container, which shutdown level is lower than a critical level. As a result, the effect can be taken into account that even after a shutdown of the fan residual cleaning liquid can drain from the second heat exchanger and thus further fills the collecting container. The switch-off level can thus be in particular a level which is so far below the critical level that the residual cleaning liquid (for example water) does not reach the critical level or only just reaches it.

It is also an embodiment that the critical level is a maximum level of the collection container. By this choice, overflow of the cleaning liquid in the collecting container into the air flow channel and carryover of the overflowed cleaning liquid by process air which sweeps over the cleaning liquid, can be avoided.

It is also an embodiment that the critical level is a level at which no detergent is pressed from the collecting container into the air flow channel when the fan is operated. By this choice can be avoided that there is a carryover of cleaning liquid with the process air, which sweeps over a surface of the cleaning liquid, which is still in the collecting container. The cleaning liquid does not reach its maximum level to have. Thus, the knowledge is taken into account that even if the amount of the cleaning liquid can be completely absorbed by the collecting container, it can lead to a carryover of cleaning liquid with the process air that sweeps over the surface.

The object is also achieved by a method for operating a domestic appliance with a fan for moving air in an air flow channel in a flow direction, with a first heat exchanger and a second heat exchanger, which are arranged one behind the other in the air flow channel with respect to the flow direction, with a Cleaning device for cleaning the first heat exchanger with cleaning liquid, wherein at operated cleaning device and operated fan at least a portion of the cleaning liquid can be directed to the second heat exchanger, and with a collecting container for dripping from the second heat exchanger cleaning liquid, the fan operated depending on a level of the collecting container becomes. The method can be designed analogously to the household appliance and has the same advantages.

• Fig.1 zeigt eine Skizze eines Wärmepumpen-Wäschetrockners mit einem zweiten Wärmetauscher und
• Fig.2 zeigt verschiedene zu einem Abspülvorgang des zweiten Wärmetauschers zugehörige Zeitdiagramme.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following schematic description of an embodiment which will be described in detail in connection with the figures of the accompanying drawings.

• Fig.1 shows a sketch of a heat pump tumble dryer with a second heat exchanger and
• Fig.2 shows various associated with a rinsing of the second heat exchanger time diagrams.

Fig.2 shows simplified in three diagrams to a rinsing of a second heat exchanger - eg the second heat exchanger 6 of the heat pump tumble dryer 1, to which reference is made in the following - associated time courses.

An upper diagram shows a differential volume of water discharged by the cleaning device 5 over a time t. At a time t = 0, the purifier 5 starts discharging water at a discharge rate dVabr / dt, where Vabr is a volume of the water discharged from the purifier 5. This can be implemented, for example, by opening a valve between a downpipe of the cleaning device 5 and a water tank of the cleaning device 5 arranged above it (not shown). Upon reaching a time t = tend no more water W is discharged from the cleaning device 5. A purge time of the purifier 5 corresponding to tend - (t = 0) = tend may be fixed, e.g. by a volume of the water tank of the cleaning device 5.

A middle diagram shows an operating time of the fan 7 which starts at t = 0 and ends when a stop time t = tstop is reached. Since the water W discharged from the cleaning device 5 reaches the second heat exchanger 6 only during operation of the fan 7, the stopping time tstop corresponds to the flushing duration of the second heat exchanger 6, that is to say that practically flush is valid. For example, a purge rate dV / dt of the second heat exchanger 6 may be at least about dV / dt = 0.5 · dVabr / dt. For times tstop <t <tend, the first heat exchanger 4 is cleaned.

The lower diagram shows a time evolution of the filling level L resulting from the upper diagram and the middle diagram in the collecting container 11. At the time t = 0, the collecting container 11 is empty and fills up by the water W dripping down from the second heat exchanger 6. However, it may also come at a time delay between the beginning of the cleaning at t = 0 and the time at which water first enters the collecting container 11. With dripping of the water W, the collecting container 11 fills, since a filling rate of the water W is greater than its drainage rate.

Upon reaching the rinsing time tspül a shut-off level Lstop has been reached, which is lower than a critical level Lkrit. The shut-off level Lstop corresponds to an associated shut-off volume of the water in the collecting container 11, and the critical level Lkrit a critical volume of the water W. The critical level Lkrit corresponds to a level L, from the water W can be abducted to a considerable extent with the process air P. This can occur at a high level L - in particular the maximum level Lmax.

After reaching the shut-off level Lstop still dripping water W into the collecting container 11 and thereby increases the level L on. However, the critical level Lkrit is not reached. The volume of the trickling water W is limited and can be considered constant.

With filling collecting container 11 and thus with increasing level L, the second heat exchanger 6 can be at least partially in the water W. This is particularly the case when the second heat exchanger 6 is at least partially disposed in the collecting container. This can further improve an effect of the cleaning.

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

Generally, "on", "an", etc. may be taken to mean a singular or a plurality, in particular in the sense of "at least one" or "one or more" etc., unless this is explicitly excluded, e.g. by the expression "exactly one", etc.

Also, a number may include exactly the specified number as well as a usual tolerance range, as long as this is not explicitly excluded.

LIST OF REFERENCE NUMBERS

1

Heat pump dryer

2

washing drum

3

Process air duct

4

First heat exchanger

5

cleaning device

6

Second heat exchanger

7

Fan

8th

compressor

9

expansion valve

10

Refrigerant pipe

11

receptacle

12

control device

dV / dt

Rinsing rate of the second heat exchanger

dVabr / dt

Dispensing rate from the cleaning device

L

level

Lkrit

Critical level

Lmax

Maximlaer level

Lstop

Shutdown level

W

water

tend

Rinsing time of the cleaning device

tspül

Flushing time

t stop

stopping time

Claims (10)

Household appliance (1), comprising a fan (7) for moving air in an air flow channel (3) in a flow direction, a first heat exchanger (4) and a second heat exchanger (6), which are arranged one behind the other in the air flow channel (3) with respect to the flow direction, - A cleaning device (5) for cleaning the first heat exchanger (4) with cleaning liquid (W), wherein at operated cleaning device (5) and operated fan (7) at least a portion of the cleaning liquid (W) on the second heat exchanger (6) can be directed , and - A collecting container (11) for from the second heat exchanger (6) dripping cleaning fluid (W),
in which - The fan (7) depending on a level (L) of the collecting container (11) is operable. Domestic appliance (1) according to claim 1, wherein the fan (7) is sustainable depending on the level (L) of the collecting container (11). Domestic appliance (1) according to claim 2, wherein the fan (7) before an end (tend) of an operating time of the cleaning device (5) is sustainable. Domestic appliance (1) according to one of the preceding claims, wherein the fan (7) depending on a measured level (L) of the collecting container (11) is haltable. Domestic appliance (1) according to one of the preceding claims, wherein the fan (7) is sustainable as a function of a calculated fill level (L) of the collecting container (11). Domestic appliance (1) according to one of claims 2 to 5, wherein the fan (7) upon reaching a shut-off level (Lstop) of the collecting container (11) is sustainable, which shutdown level (Lstop) is lower than a critical level (Lkrit ). Domestic appliance (1) according to claim 6, wherein the critical level (Lkrit) is a maximum level (Lmax) of the collecting container (11). Domestic appliance (1) according to claim 6, wherein the critical level (Lkrit) is a level (L) in which when operated fan (7) no detergent (W) from the collecting container (11) in the air flow channel (3) is pressed. Heat pump household appliance (1) according to any one of the preceding claims, wherein the heat pump household appliance (1) is a clothes drying apparatus, the cleaning agent water (W) and the air flow channel (3) is a process air duct. Method for operating a domestic appliance (1) with a fan (7) for moving air in an air flow channel (3) in a flow direction, with a first heat exchanger (4) and a second heat exchanger (6) which are arranged in the air flow channel (3) with a cleaning device (5) for cleaning the first heat exchanger (4) with cleaning liquid (W), wherein when operated cleaning device (5) and operated fan (7) at least a part of the cleaning liquid (W) to the second heat exchanger (6) can be directed, and with a collecting container (11) for the second heat exchanger (6) dripping cleaning fluid (W), wherein the fan (7) depending on a level (L) of the collecting container (11) operated becomes.

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