DE102010029892A1 - Condensation dryer with integrated heat exchanger cleaning and process for its operation - Google Patents

Abstract

The invention relates to a condensation dryer 1 with a drying chamber 3 for objects to be dried, a process air duct 2, in which there is a heater 4 for heating the process air, a heat exchanger 5, 39 for cooling the process air after passage through the drying chamber 3 and a blower 6 for the transport of the process air, a cleaning device 7 working with an aqueous liquid 26, which generates at least one liquid jet, and a control device 8, the cleaning device 7 changing the direction and / or intensity of the at least one liquid jet during its operation. The invention also relates to a preferred method for operating this condensation dryer.

Description

The invention relates to a condensation dryer with integrated heat exchanger cleaning and a preferred method for its operation.

A condensation dryer, the operation of which is based on the condensation of the evaporated by means of warm process air moisture from the laundry, does not require exhaust hose and is very popular because it can be used in an internal bathroom or a laundry room of a larger residential complex. In a condensation dryer (hereinafter also abbreviated to "dryer"), air (so-called process air) is passed through a fan via a heater into a drum containing wet laundry as a drying chamber. In the drum are moist, to be dried items of laundry. The hot air absorbs moisture from the laundry to be dried. After passing through the drum, the now moist process air is directed into a heat exchanger, which is usually preceded by a lint filter. In this heat exchanger (eg air-to-air heat exchanger or heat sink of a heat pump), the moist process air is cooled so that the water contained in the moist process air condenses. The condensed water (condensate) is then usually collected in a suitable container and the cooled and dried air again fed to the heater and then the drum.

From the process air lint contained in the laundry items to be dried, which are small floatable tissue particles are entrained in the passage through the drying chamber. Larger lint are retained in a lint filter. However, some of the finely divided fluff passes through the lint filter and deposits behind it in the process air duct. The deposit of fluff is particularly pronounced in the heat exchanger, where, due to the cooling of the moist, warm process air, condensate is present and the lint is moistened, so that it sticks down. The flakes deposited on the heat exchanger constitute a hindrance to the process air flowing through the heat exchanger and impair the heat exchange, so that the efficiency of the condensation dryer decreases and its susceptibility to interference can increase.

Frequently, the heat exchangers are removable, in particular air-to-air heat exchanger, so that they can be removed from the condensation dryer for cleaning and after removal of adhering lint, for example by rinsing with a rinsing fluid such as water, can be re-used in the dryer. However, this is not necessarily possible if a heat sink of a heat pump is used as the heat exchanger. The components of a heat pump are usually firmly connected to each other and not reversible removed from the condensation dryer. This applies, for example, to the components of a compressor heat pump, since these are combined in a completely closed and not readily separable circuit for a refrigerant. It also applies to the components of a thermoelectric heat pump, which forms a compact and hardly separable unit, including the Peltier elements, in which the Peltier effect, which causes the pumping of heat. It may also apply to other heat pumps, such as adsorption heat pumps and heat pumps, which use a regenerative gas cycle.

For a heat exchanger of a condensation dryer thus determining a need for cleaning and cleaning are associated with a considerable effort for the user. Failure to clean the heat exchanger in a timely manner may degrade the performance of the condensation dryer or even interfere with failure of the condensation dryer, requiring repair. There are therefore measures for an internal cleaning of a dryer, in particular an internal cleaning of a heat exchanger known, wherein the cleaning condensate used in the condensate is often used for cleaning.

The DE 10 2006 006 080 A1 describes a cleaning device for a disposed within a process air circuit of a household laundry dryer component, in particular for a heat exchanger, with a channel region of the process air circuit to flood the component via an inlet with a cleaning liquid to flood after completion of the cleaning process via a Discharge blocking member, wherein the channel region is associated with an exciter device with which the cleaning liquid is to be set in motion.

The DE 199 43 125 A1 describes a method for cleaning a portion of a guide of a process air stream in a domestic laundry dryer, in which outside of a drying phase, in which generated by means of a blower, the process air flow and brought into a drying room in contact with the laundry to be dried, in a cleaning phase with the fan off Section of the process air guide is at least partially flooded for a certain period of time with a liquid which is removed at the end of the cleaning phase of the flooded portion of the process air duct. Preferably, in the cleaning phase for flooding condensate from a process air flow direction behind the drying room lying heat exchanger used to condense the moisture in the process air.

The DE 37 38 031 C2 describes a method and apparatus for removing lint from a condensate separator formed as a heat exchanger. At least one process air channel is hermetically sealed against the coolant and arranged for discharging the condensate, which is collected in a disposed below the heat exchanger collecting container until emptying. In the method, at least a part of the collected condensate is flushed during a time-limited program section at least one inner surface of the process air duct. In the apparatus, the heat exchanger is provided with a flushing device which has at least one nozzle directed onto at least one inner surface of the process air duct.

The WO 2008/077708 A1 describes a domestic appliance and a method for removing lint from a heat exchanger of this domestic appliance. Here, especially during a drying process, condensate generated in the domestic appliance is deflected as a rinsing liquid during a cleaning phase depending on the strength of an air flow and flows depending on the deflection through different areas of the heat exchanger. However, an efficient cleaning of the heat exchanger can only be achieved with a sufficiently large volume and / or with sufficiently fast flowing rinsing liquid. How to achieve this is left open.

The WO 2008/119611 A1 describes a method and an apparatus for cleaning a arranged within a process air cycle of a washer or dryer component, in particular an evaporator of a condenser device, by means of condensate, which is recovered in the process air cycle from the wet laundry and collected in a condensate pan, from which it above the evaporator provided rinse tank is passed. From the outlet side of the condensate is discharged by sudden opening of the respective washing container to said component.

The DE 42 12 965 A1 describes a condensation dryer with a drum and a lying in the course of a process air flow condensation water tank having a temperature-controlled cooling circuit with pump and a water inlet and a water outlet. The water tank contains at least one condensation filter element which is arranged above the water level in the course of the process air and in the area of action of spray nozzles of the cooling air circuit. In the embodiment of 1 During the drying process, the cooling water in the water tank is pumped continuously over the pump and a three-way valve, wherein spray nozzles ensure a uniform film of water on the condensation filter elements with simultaneous flushing or linting of lint.

The DE 10 2006 018 469 A1 describes a dryer for laundry, in which the dehumidification of the air conveyed in recirculation mode takes place by condensation on a cooler which is part of a heat pump, wherein the dryer has a device for flooding, spraying, flowing through and / or overflow of the evaporator and / or compressor wherein a filter filters the water used for flooding, spraying, flowing and / or overflowing.

The DE 37 38 033 A1 describes a device for monitoring the degree of flow. When cleaning a heat exchanger in a dryer, it may be due to the process that due to a low load of laundry items to be dried and / or low humidity in the laundry for sufficient rinsing of the heat exchanger is too little condensate. A further disadvantage of repeated flushing with condensate during a drying cycle is that the impurities with lint, etc., which are found with the rinsing of the heat exchangers in the water of the condensate tray, must be filtered out and disposed of before the next flushing of the heat exchangers. Although this can be solved by rinsing instead of condensate with tap water. Ie. the dryer is provided with a water connection. The problem then is that the amount of water necessary to achieve optimal cleaning results mostly due to the low water pressure, which prevails in many countries, can not be adjusted.

Against this background, the object of the present invention was to provide a condensation dryer in which a component arranged in the process air duct, in particular a heat exchanger, can be cleaned efficiently in an improved manner.

The solution of this object is achieved according to this invention by a dryer with the features of the corresponding independent claim and the method of the corresponding independent claim. Preferred embodiments of the dryer according to the invention are listed in corresponding dependent claims. Preferred embodiments of the dryer according to the invention correspond to preferred embodiments of the method according to the invention and vice versa, although this is not explicitly stated herein.

The invention thus relates to a condensation dryer with a drying chamber for objects to be dried, a process air duct in which there is a heater for heating the process air, a heat exchanger for cooling the process air after passing through the drying chamber and a blower for the transport of the process air cleaning device operating with an aqueous liquid, which generates at least one liquid jet, and a control device, wherein the cleaning device changes the direction and / or intensity of the at least one liquid jet during its operation.

In a preferred embodiment of the condensation dryer, the cleaning device comprises a liquid-carrying channel with a channel exit in which there is an electrically or hydraulically movable body, which changes its position during operation of the cleaning device to a varying part of the cross section of the channel exit for the Flow of the aqueous liquid (hereinafter abbreviated to "liquid") release. In this case, the released cross section of the channel outlet preferably varies in time with respect to its position and size.

The electrically or hydraulically movable body according to the invention is not limited, as long as it can cause a temporal variation of the cross section of the channel exit for the flow of the aqueous liquid. The movable body may be a plate or a ball, for example.

The movable body will usually cover during operation of the cleaning device different areas of the cross section of the channel exit and thus direct the liquid jet in different directions. Due to the reduced for the passage of the liquid cross-section of the channel outlet of the flow of the liquid is carried out at an increased flow rate. The liquid jet therefore generally meets at an increased speed to be cleaned components of the dryer and can thus develop an improved cleaning effect.

The cleaning device thus preferably has at least one electrically or hydraulically movable body, which allows the change of direction and / or intensity (flow velocity and / or cross section) of the at least one liquid jet. In this case, the movable body is preferably moved hydraulically by means of the aqueous liquid.

However, a temporal variation of the cross section of the channel exit can also be achieved, for example, by rotating a disc provided with a recess about a longitudinal axis of the channel in the channel, for example via an electric drive.

In the event that the movable body is moved hydraulically by means of the aqueous liquid, the movement of the movable body can also be influenced by selecting a material of specific density and thus a certain buoyancy.

The cleaning device preferably has a channel with a channel outlet, which is adjoined by a nozzle. Due to the shape of the nozzle, the at least one liquid jet can be directed specifically to be cleaned components of the dryer. It is preferred that the cleaning device subsequently to a channel for guiding the aqueous liquid has a nozzle whose cross-section increases with increasing distance from the channel.

Preferably, the movable body is at rest, the channel at the channel exit from the nozzle separate. If the liquid then enters the channel during operation of the cleaning device, the body is moved due to the action of the liquid depending on the densities of body and liquid and the flow conditions in the channel, that it leaves its position at rest and forms part of the cross section of the Channel output releases.

In a particularly preferred embodiment of the dryer, a bypass input and a bypass outlet are located in the channel, so that a part of the aqueous liquid flowing in a bypass between the bypass input and bypass outlet generates a turbulent flow in the aqueous liquid surrounding the movable body and thus the movable body can move.

One or more bypasses can be used. In addition, the position of bypass input and bypass output, as well as the angle that the bypass forms with the channel, especially at the bypass output, can be set to provide optimum flow for the movement of the moving body. In addition, devices may be provided in the channel and / or bypass which provide flow fluctuations and thus contribute to a turbulent flow around the movable body.

It is also preferred that the channel directly before the channel exit a bulge which can at least partially receive the movable body, so that the released cross section of the channel outlet varies during the operation of the cleaning device. Herein, "shared cross section" means that part of the cross section of the channel exit that is available for the flow of liquid. "Directly in front of the channel exit" means a spatial proximity that is sufficient for a movement of the movable body to bring about a variation of the cross section of the channel exit available for the passage of the aqueous liquid.

In the dryer according to the invention, the cleaning device operates with an aqueous liquid. This can be provided in various ways. For this purpose, the cleaning device is preferably connected to a rinsing container, a water supply and / or a condensate tray.

Under water supply is generally understood herein a water supply available in household tap water, which is usually with a tap water pressure of at least 3 bar, but sometimes with a higher pressure, such. B. with 6 bar, is provided.

The connection with a water supply allows the cleaning with fresh water, which contains no impurities. The connection with a condensate tray allows the use of condensate in the dryer. Since the condensate in the condensate tray generally contains lint, filtration of the condensate and / or admixture of fresh water from a water supply is performed prior to using the condensate in the purifier.

The water supply and / or the condensate tray may be connected directly to the cleaning device, possibly with inter-folding of a pump and / or a filter. However, the fresh water from the water supply and / or the condensate can also initially reach a rinsing tank, which in turn is connected to the cleaning device.

The rinsing container generally contains an aqueous rinsing liquid provided for the purpose of cleaning a component in the process air duct (hereinafter also abbreviated to "rinsing liquid"). The rinsing liquid generally comprises condensate and / or tap water from the water supply. To improve the cleaning effect, additives such as other solvents (for example alcohols) or surface-active agents may be added to the rinsing liquid. The rinsing container can also be part of a larger collecting container for aqueous liquid, in which case the portion of the collecting container containing the rinsing liquid can also be referred to as rinsing chamber. If in the following of washing containers is mentioned, both possibilities should be covered. The rinse tank can be fixed or removable installed in the condensation dryer.

The rinsing container for the aqueous rinsing liquid optionally used in the dryer according to the invention preferably comprises a lower container opening and a connecting line is arranged between a heat exchanger and the rinsing container.

The cleaning device is preferably carried out immediately or shortly after completion of a drying operation of wet laundry to be dried, since at this time adhering to the component or heat exchanger impurities, especially lint, are still wet or dissolved and are relatively easily removed by the dispensed rinse liquid. In addition, at this time condensate tray or rinse tanks are usually filled with condensate, which is used to clean the component, eg. B. a heat exchanger can be used. Furthermore, generally after each drying process, a longer time passes until the next drying process, so that there is enough time to remove the rinsing liquid.

The cleaning device can be used for cleaning of various components of the dryer, preferably those components are cleaned, the inner surfaces of which come into contact with process air, in particular with lint laden process air. The components to be cleaned are therefore preferably the process air duct after the drum and arranged in the process air duct heat exchanger.

In a particularly preferred embodiment of the condensation dryer, therefore, the at least one liquid jet is directed onto the heat exchanger. The heat exchanger is preferably an air-to-air heat exchanger or a heat sink of a heat pump.

The cleaning device can be manually put into operation by a user of the dryer or automatically. In both cases, the condensation dryer preferably has a means for detecting a need for cleaning the heat exchanger.

In a preferred embodiment, the condensation dryer on means for detecting a cleaning requirement for the heat exchanger, which for determining the cleaning requirement for the heat exchanger, a Usage metric U determine, compare them with a predetermined value U _lim and determine when reaching U _lim , ie under the condition U _lim = U, the need for cleaning.

In a preferred embodiment, a counter is provided as the means for detecting the need for cleaning, which determines the number n of drying processes already carried out and compares them with a predetermined limit number n _lim . This counter can preferably be reset when cleaning the heat exchanger is performed.

In a further preferred embodiment, a clock is present as a means for detecting the cleaning requirement, which determines a total duration t _sum of previously performed drying processes and compares with a predetermined limit duration t _lim . This clock can preferably be reset when cleaning the heat exchanger.

Optionally, the condensation dryer according to the invention comprises in a further preferred embodiment as a means for detecting the cleaning requirement, an evaluation unit which determines a total amount M of previously dried laundry items and compared with a predetermined limit total amount M _lim . The value for the total amount M may be preferably reset when cleaning of the heat exchanger is performed.

In addition, the condensation dryer can preferably have a sensor for measuring the volume flow as a means for detecting the need for cleaning in the process air duct. The evaluation unit, which determines a total volume flow V and compares it with a limit volume flow V _lim , can then set the cleaning device in motion. The value V is then preferably reset.

Finally, by the evaluation unit in a further preferred embodiment, a temperature gradient .DELTA.T can be determined via a temperature sensor arranged behind the heater, as viewed in the direction of the process air flow. This temperature gradient is compared with a limiting temperature gradient ΔT _lim . When the limit temperature gradient is exceeded, the cleaning process is triggered.

It is inventively preferred that the condensation dryer has an acoustic and / or visual display means for displaying the cleaning requirement and / or for displaying the operation of the cleaning device.

After determining the cleaning requirement for the heat exchanger, a cleaning of the heat exchanger is preferably carried out with the cleaning device. The cleaning using the aqueous liquid may be performed automatically or controllably by a user of the condensation dryer. Preferably, this can be set on the condensation dryer, whether automatic or manual cleaning should be performed.

The condensation dryer according to the invention can be designed as a pure dryer, but also as a washer-dryer. A washer-dryer is here understood to mean a combination appliance which has a washing function for washing laundry and a drying function for drying wet laundry. A washer-dryer has the advantage that it is already connected as such to a water supply.

The invention also relates to a method for operating a condensation dryer with a drying chamber for objects to be dried, a process air duct, in which a heater for heating the process air, a heat exchanger for cooling the process air after passing through the drying chamber and a blower for the transport of the Process air are located, a working with an aqueous liquid cleaning device which generates at least one liquid jet, and a control device, wherein the cleaning device changes the direction and / or intensity of the at least one liquid jet during operation and applied to be cleaned components of the condensation dryer with the at least one liquid jet become.

The components to be cleaned, in particular the heat exchanger, can be cleaned with a predetermined amount of the aqueous liquid, wherein the amount used can be adjusted depending on the extent of a determined cleaning requirement.

The inventive method for operating a condensation dryer preferably uses a condensation dryer with means for detecting a need for cleaning the heat exchanger, said means for determining the cleaning requirement for the heat exchanger preferably determine a degree of use U, comparing them with a predetermined value U _lim and upon reaching U _lim , ie under the condition U _lim = U, determine the need for cleaning.

The type and size of the usage measure U and the predetermined value U _lim depend on the type of funds used. Is that a means? Counter, the usage metric U will usually be a natural number, which is incremented by one with each drying program performed. Accordingly, the predetermined value U _lim when using a counter is usually also a natural number. For the case U = U _lim , a need for cleaning is determined and in general the process according to the invention is initiated.

Accordingly, the measured value U and the predetermined value U _lim when using a clock are each a period .DELTA.t and when using a certain total amount M of previously dried laundry each weight.

In the method according to the invention, it is preferred that the cleaning requirement for the heat exchanger, which is preferably to be cleaned, be indicated acoustically and / or optically. Since this makes it possible for a user of the condensation dryer to recognize the need for cleaning, an acoustic and / or optical display of the cleaning requirement, in addition to automatic cleaning, also allows control of the cleaning by the user.

In the process according to the invention, the aqueous liquid preferably comprises condensate. In this case, it is again preferred that the aqueous liquid from the rinsing container, into which the heat exchanger is passed, is subsequently collected after use in a condensate tray and pumped back into the rinsing container. In the method, it may be specified that such a cycle is run more than once.

The controller may perform automatic cleaning even at night time if the user does not use the dryer anyway. In any case, the dryer may indicate an imminent cleaning phase and may alert the user that a condensate tank used as a flush tank should not be emptied so that enough condensate is available for cleaning with the cleaner.

In a preferred embodiment of the method according to the invention, in which the cleaning is carried out by a user of the condensation dryer, the rinsing container is filled, for example, by adding tap water from the water supply up to a certain amount of water (eg 3 l). The added amount of water will depend on whether the rinse tank is used to store condensate and may already contain condensate. Then, for example, a cleaning program is selected by the user on the condensation dryer. One or more cleaning steps are then initiated via the control device. The start and end of the cleaning steps are preferably displayed audibly and / or visually to the user. After completion of the cleaning steps and, if necessary, pumping back the used rinsing liquid, the user can manually dispose of the rinsing liquid by removing and emptying, depending on the contamination of the used rinsing liquid in the case of a removable rinsing container. Alternatively, the rinsing liquid can be automatically disposed of via a drain hose from the condensation dryer.

The invention has the advantage that in the case of a condensation dryer, cleaning with aqueous liquid having an increased effect is carried out. All areas of a component to be cleaned in the dryer in the process air duct can be cleaned with a sufficiently large amount of water, which moreover can be used at an elevated pressure. Thus, automatically or by influencing a user, the heat exchanger of a condensation dryer can be cleaned efficiently. In embodiments of the invention, a cleaning requirement of a heat exchanger can also be determined without the need for opening the condensation dryer. The invention is particularly advantageous when using a heat pump, since the heat sink of a heat pump usually can not be removed from the condensation dryer for cleaning. The heat exchanger of the condensation dryer can be easily and conveniently cleaned without mechanical intervention in the device. No brushes, filters or brushes are needed for cleaning. Since the invention allows a regular, customized to the needs cleaning of the heat exchanger, a dryer with improved efficiency and a significantly reduced susceptibility is possible.

Further details of the invention will become apparent from the following description of non-limiting embodiments of the condensation dryer according to the invention and the inventive method for operating this condensation dryer. It is related to the 1 to 4 taken.

1 shows a vertical section through a condensation dryer according to a first embodiment of the invention, wherein the condensation dryer is designed as a vented dryer.

2 shows a vertical section through a condensation dryer according to a second embodiment, which is designed as a circulating air dryer.

3 shows a section through a cleaning device, the four liquid jets and can be used in a third embodiment of a condensation dryer according to the invention.

4 shows an enlarged section through the cleaning device of 3 wherein the generation of a liquid jet is shown in detail.

In the 1 to 4 filled arrows indicate the flow direction of the process air and open arrows indicate the flow direction of an aqueous liquid.

The in 1 illustrated dryer 1 has a drum rotatable about a horizontal axis as a drying chamber 3 on, within which carriers 25 are attached to the movement of laundry items, not shown here during a drum rotation. Supply air is in the process air duct 2 by means of a blower 6 from the Zulufteingang 23 via an air-to-air heat exchanger 5 and an electric heater 4 through the drum 3 guided. It is by the electric heater 4 heated air from the one door 22 opposite side of the drum 3 through their perforated bottom into the drum 3 directed.

After leaving the drum 3 the process air laden with moisture is in the process air duct 2 over the air-air heat exchanger 5 to an exhaust air outlet 24 directed. In this case, the process air initially flows through the filling opening of the drum 3 to a lint filter 38 within the door closing the filling opening 22 and then gets in the door 22 deflected downwards and on to the air-to-air heat exchanger 5 directed. As a result of cooling, the moisture absorbed by the process air from the items of laundry condenses there and is stored in a condensate tray 17 collected.

The condensate tray 17 is via a condensate channel 18 in which there is a pump 28 located, with a rinse tank 19 connected, in which an aqueous liquid 26 located. The washing container 19 is also about a connection 33 and a two-way valve 29 for controlling the water supply to a water supply 27 connected. From the washing container 19 can the aqueous liquid 26 via a lower container opening 21 and a connection line 20 in a cleaning device 7 reach. The cleaning device 7 includes a channel in the embodiment shown here 9 that's over the connection line 20 with the washing container 19 connected is. There is a bypass in the canal 16 as well as a bulge 11 in which there is a movable body 10 which is designed here as a ball. The movable ball 10 disconnects at rest of the cleaning device 7 the channel 9 from a nozzle 13 , If aqueous fluid gets through the channel 9 and the bypass 16 , so in the the movable ball 10 surrounding aqueous liquid 26 creates a turbulent flow, so that the ball 10 in the bulge 11 moved back and forth and so exposes different parts of the cross section of a channel output not shown here in detail. As a result, the flow rate and direction of one of the nozzles change temporally 13 passing liquid jet. The nozzle is designed so that its cross section increases with increasing distance from the channel outlet. The jet of liquid from the nozzle 13 is in the embodiment shown here on the inner surface of the air-to-air heat exchanger 5 directed. Due to the varying orientation of the liquid jet, different parts of the inner surface of the air-to-air heat exchanger can 5 be efficiently cleaned of adhering lint.

The in the cleaning device 7 used aqueous liquid 26 is in this embodiment a serving as a storage rinse tank 19 taken. The washing container 19 can with fresh water from the water supply 27 and / or with condensate from the condensate tray 17 , from which the condensate via a condensate channel 18 by means of the pump 28 can be pumped. For cleaning, the lower container opening 21 opened and the aqueous liquid 26 through the connection line 20 in the cleaning device 7 passed it as a liquid jet, which changes its direction and intensity, for cleaning in the air-to-air heat exchanger 5 directed.

The aqueous liquid used in the cleaning device 26 can after cleaning the heat exchanger 5 as shown here, for example, in the condensate tray 17 collected and reused in the washing 19 be pumped or disposed of in a manner not shown here.

In the 1 shown water supply 27 is in particular a water pipe system of a building.

The dryer of the embodiment shown here enables automatic or manual starting of the cleaning device 7 and thus the inventive method.

For automatic starting or as information for a user of the dryer in the case of manual starting, in the first embodiment shown here, a need for cleaning can be determined.

In the process air duct 2 is located in this embodiment behind the heater 4 one sensor 34 for volume flow measurement. This is done by an evaluation unit 37 the determination of a total volume flow V of the process air and its comparison with a limiting volume flow V _lim . Assuming that at a pollution of the heat exchanger 5 the flow rate of the process air drops, is determined by the evaluation unit 37 the cleaning process is triggered when the total volume flow V _falls below the limit volume flow V _lim . The placement of the as feeler 34 for volume flow measurement trained sensor 34 in the process air circuit is largely uncritical, but is preferably behind the heater 4 because there the process air flow is largely free of lint and the like possibly impairing loads and thus long-term reliable measurement can be expected.

As an alternative to the feeler 34 for a volume flow is also a placed at the designated location sensor for temperature measurement into consideration, by means of which the evaluation unit 37 a temperature gradient .DELTA.T of the process air is determined and compared with a limit temperature gradient .DELTA.T _lim . Assuming that at a pollution of the heat exchanger 5 with decreasing volume flow of the process air, its temperature behind the heater 4 rises, is through the evaluation unit 37 the cleaning process is triggered when the temperature gradient ΔT exceeds the limit temperature gradient ΔT _lim .

At the in 1 shown embodiment are additionally as a means for determining a cleaning requirement of the air-to-air heat exchanger 5 in addition a counter 33 for the number of drying processes carried out, one o'clock 34 as well as a correspondingly programmed evaluation unit 37 available. These are either part of the control device 8th of the condensation dryer 1 or her assigned.

When determined cleaning needs by the control device 8th or the evaluation unit 37 at the in 1 shown embodiment triggered a cleaning process in which the air-air heat exchanger 5 by means of the cleaning device 7 as described above. This process can be repeated if necessary.

The drum 3 will be in the in 1 shown embodiment at the rear bottom by means of a pivot bearing and front mounted by means of a bearing plate, wherein the drum 3 with a brim on a sliding strip 31 on the bearing plate 32 rests and is held at the front end. The control of the dryer via a control device 8th by the user via a control unit 36 can be regulated.

At the in 1 In the embodiment shown, the blower 6 and the drum 3 through the engine 30 driven.

2 shows a vertical section through a condensation dryer 1 according to a second embodiment of the invention, wherein the dryer is designed as a circulating air dryer. In this embodiment, therefore, a Zuluftzugang and an exhaust duct are missing. In contrast to the embodiment of 1 the cooling of the warm, moisture-laden process air takes place from the drum 3 in the evaporator 39 a heat pump, which also has a condenser 40 , a compressor 41 and a throttle valve 42 contains.

The in 2 illustrated dryer 1 has a drum rotatable about a horizontal axis as a drying chamber 3 on, within which carriers 25 are attached to the movement of laundry during a drum rotation. In the closed process air duct 2 is process air with the help of a blower 6 via an electric heater 4 directed. The heated process air then enters the drum 3 where moisture is removed from damp laundry items, not shown here. It will be the electric heater 4 heated process air from the rear, ie from a door 22 opposite side of the drum 3 through whose perforated bottom into the drum 3 directed. The moist, warm process air leaves the drum 3 over a lattice 38 and flows in the process air duct 2 to the evaporator 39 the heat pump. The moist, warm process air is in the evaporator 39 cooled and the vaporized refrigerant of the heat pump via a compressor 41 to the liquefier 40 directed. In the liquefier 40 The refrigerant liquefies with release of heat to the cooled and dehumidified process air flowing in the process air duct. The then present in liquid refrigerant is via the throttle valve 42 turn to the evaporator 39 passed, whereby the refrigerant circuit is closed.

That in the evaporator 39 accumulating condensate is in a condensate tray 17 collected and with the help of a condensate pump 28 in a condensate channel 18 to a cleaning device 7 pumped. In the cleaning device 7 This condensate and / or fresh water can come from a water supply 27 to the cleaning of the evaporator provided in this embodiment 39 be used.

The cleaning device 7 includes here a channel 9 that with the condensate pan 17 and the water supply 27 connected is. In the channel 9 there is a bypass 16 as well as a bulge 11 in which a movable body formed as a ball 10 located. The movable ball 10 disconnects at rest of the cleaning device 7 the channel 9 from a nozzle 13 , If aqueous fluid gets through the channel 9 and the bypass 16 , so in the the movable ball 10 surrounding aqueous fluid creates a turbulent flow, causing the ball 10 in the bulge 11 moved back and forth and so exposes different parts of the cross section of a channel output not shown here in detail. The ball 10 is thus moved hydraulically through the aqueous liquid. As a result, the flow rate, cross section and direction of one of the nozzles change with time 13 passing liquid jet. The nozzle 13 is here designed so that their cross section increases with increasing distance from the channel exit. The jet of liquid from the nozzle 13 is in the embodiment shown here on the inner surface of the evaporator 39 directed. Due to the varying orientation of the liquid jet, different parts of the interior surface of the evaporator may be used 39 be efficiently cleaned of adhering lint.

That in the cleaning device 7 possibly used condensate previously in the evaporator 39 was incurred here by means of a pump 28 from the condensate tray 17 via a condensate channel 18 to the cleaning device 7 pumped. After cleaning, the used aqueous liquid in the condensate tray 17 collected and back to the cleaning device 7 be pumped. This cycle can be repeated if necessary. In the condensate channel 18 a filter, not shown here, may be present for separating lint from the condensate.

In addition, for cleaning in the cleaning device 7 the second embodiment also directly fresh water from the water supply 27 be used.

The aqueous liquid used for the purification may be as for 1 mentioned re-used or disposed of.

At the in 2 shown second embodiment of a dryer according to the invention no means for determining a cleaning requirement are provided. Therefore, the controller is 8th designed so that each after one or more drying process automatically cleaning with the cleaning device 7 is carried out.

Otherwise, the meaning of the further reference numerals to the 1 referenced, in which they have the same function.

3 shows a section through a cleaning device 7 , which is used in a third embodiment of a condensation dryer according to the invention. The cleaning device 7 includes in the section shown here from a third embodiment of the dryer, a liquid distributor 43 , the water from a not shown here supply of fresh water and / or condensate on the four spray heads shown here 44 to 47 distributed. With the cleaning device shown here 7 Four liquid jets can be generated. The liquid jets can be generated independently or independently of each other. To the cleaning device used in the dryer according to the invention 7 to explain in detail, are the four spray heads 44 to 47 in different operating states, recognizable by the differently strong and differently oriented liquid jets. The operating state of spray head 47 (Hibernation), however, can only be realized when in the liquid distributor 43 no aqueous liquid is located or the liquid distributor 43 by a mechanism not shown here by the spray head 47 is disconnected.

Each of the spray heads 44 to 47 has a channel 9 on, in between a bypass entrance 14 and a bypass output 15 a bypass 16 as well as a bulge 11 are located. In the bulge 11 There is a movable body formed here as a sphere 10 , which at rest (see the operating state of spray head 47 ) of the cleaning device 7 the channel 9 from a nozzle 13 separates. If aqueous fluid gets through the channel 9 and the bypass 16 , so in the the movable ball 10 surrounding aqueous fluid creates a turbulent flow, causing the ball 10 in the bulge 11 moved back and forth and so different parts of the cross section of a channel exit 12 exposes. The ball 10 is thus moved hydraulically through the aqueous liquid. As a result, the flow rate, cross section and direction of one of the nozzles change with time 13 passing liquid jet. The nozzle 13 is here designed so that their cross section increases with increasing distance from the channel exit.

In the operating state of the spray head shown here 44 is the ball 10 right from the middle of the canal 9 near the bypass exit 15 , As a result, the available for the liquid passage cross section of the bypass outlet 15 reduced. The pressure through the aqueous fluid in the bypass increases, causing the ball 11 is pushed to the left again. In particular, the ball 10 over the middle of canal 9 pressed to the left. The operating state then present is determined by the operating state of the spray head 45 illustrated. Then the ball moves 10 back to the middle of the canal 9 , In this case by means of spray head 46 illustrated operating state becomes the ball 10 from the watery Liquid flows around and gives the channel exit 12 free for the exit of the aqueous liquid, wherein the aqueous liquid here as a bundled central liquid jet from the nozzle 13 occurs.

4 shows an enlarged section through the cleaning device 7 from 3 , wherein the generation of a liquid jet in the spray head 46 according to 3 is more clearly recognizable.

LIST OF REFERENCE NUMBERS

1

condensation dryer

2

Process air duct

3

Drying chamber, laundry drum

4

(electric heating

5

Air-air heat exchanger

6

fan

7

cleaning device

8th

control device

9

Channel for guiding the aqueous liquid

10

Movable body

11

bulge

12

channel output

13

jet

14

bypass input

15

bypass output

16

bypass

17

Drain pan

18

condensate channel

19

rinse tank

20

connecting line

21

Lower container opening

22

door

23

inlet air

24

exhaust air outlet

25

takeaway

26

Aqueous liquid

27

water supply

28

pump

29

Two-way valve

30

drive motor

31

lubricating strip

32

end shield

33

Clock

34

sensor

35

counter

36

operating unit

37

evaluation

38

lint

39

Evaporator

40

Liquefy

41

compressor

42

throttle valve

43

liquid distributor

44-47

spray heads

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102006006080 A1 [0006]
• DE 19943125 A1 [0007]
• DE 3738031 C2 [0008]
• WO 2008/077708 A1 [0009]
• WO 2008/119611 A1 [0010]
• DE 4212965 A1 [0011]
• DE 102006018469 A1 [0012]
• DE 3738033 A1 [0013]

Claims (15)

Condensation dryer ( 1 ) with a drying chamber ( 3 ) for objects to be dried, a process air duct ( 2 ), in which a heating ( 4 ) for heating the process air, a heat exchanger ( 5 . 39 ) for cooling the process air after passing through the drying chamber ( 3 ) and a blower ( 6 ) for the transport of the process air, one with an aqueous liquid ( 26 ) working cleaning device ( 7 ), which generates at least one liquid jet, and a control device ( 8th ), characterized in that the cleaning device ( 7 ) changes the direction and / or intensity of the at least one liquid jet during its operation. Condensation dryer ( 1 ) according to claim 1, characterized in that the cleaning device ( 7 ) one the aqueous liquid ( 26 ) leading channel ( 9 ) with a channel output ( 12 ), in which an electrically or hydraulically movable body ( 10 ), which during operation of the cleaning device ( 7 ) changes its position to a varying part of the cross section of the channel exit ( 12 ) for the flow of the aqueous liquid ( 26 ). Condensation dryer ( 1 ) according to claim 2, characterized in that the released cross-section of the channel exit ( 12 ) varies in time with respect to its position and size. Condensation dryer ( 1 ) according to one of claims 1 to 3, characterized in that the cleaning device ( 7 ) at least one electrically or hydraulically movable body ( 10 ), which allows the change of direction and / or intensity of the at least one liquid jet. Condensation dryer ( 1 ) according to claim 4, characterized in that the movable body ( 10 ) hydraulically by means of the aqueous liquid ( 26 ) is moved. Condensation dryer ( 1 ) according to one of claims 1 to 5, characterized in that the cleaning device ( 7 ) a channel ( 9 ) with a channel output ( 12 ), to which a nozzle ( 13 ), has. Condensation dryer ( 1 ) according to claim 6, characterized in that the movable body ( 10 ) in the idle state the channel ( 9 ) at the channel output ( 12 ) from the nozzle ( 13 ) separates. Condensation dryer ( 1 ) according to claim 6 or 7, characterized in that in the channel ( 9 ) a bypass input ( 14 ) and a bypass output ( 15 ) so that one in a bypass ( 16 ) between bypass input ( 14 ) and bypass output ( 15 ) flowing part of the aqueous liquid ( 26 ) in the movable body ( 10 ) surrounding aqueous liquid ( 26 ) generate a turbulent flow and thus the movable body ( 10 ) can move. Condensation dryer ( 1 ) according to one of claims 6 to 8, characterized in that the channel directly in front of the channel exit ( 12 ) a bulge ( 11 ) comprising the movable body ( 10 ) can at least partially accommodate, so that the released cross-section of the channel exit ( 12 ) during operation of the cleaning device ( 7 ) varies. Condensation dryer ( 1 ) according to one of claims 1 to 9, characterized in that the cleaning device ( 7 ) next to a channel ( 9 ) for the guidance of the aqueous liquid ( 26 ) a nozzle ( 13 ) whose cross section increases with increasing distance from the channel ( 9 ). Condensation dryer ( 1 ) according to one of claims 1 to 10, characterized in that the cleaning device ( 7 ) with a rinsing container ( 19 ), a water supply ( 27 ) and / or a condensate tray ( 17 ) connected is. Condensation dryer ( 1 ) according to any one of claims 1 to 11, characterized in that the at least one liquid jet onto the heat exchanger ( 5 . 39 ). Condensation dryer ( 1 ) according to one of claims 1 to 12, characterized in that the heat exchanger is an air-to-air heat exchanger ( 5 ) or a heat sink ( 39 ) a heat pump ( 39 . 40 . 41 . 42 ). Condensation dryer ( 1 ) according to one of claims 1 to 13, characterized in that it comprises a means ( 33 . 34 . 35 . 37 ) for detecting a cleaning requirement for the heat exchanger ( 5 . 39 ) having. Method for operating a condensation dryer ( 1 ) with a drying chamber ( 3 ) for objects to be dried, a process air duct ( 2 ), in which a heating ( 4 ) for heating the process air, a heat exchanger ( 5 . 39 ) for cooling the process air after passing through the drying chamber ( 3 ) and a blower ( 6 ) for the transport of the process air, one with an aqueous liquid ( 26 ) working cleaning device ( 7 ), which generates at least one liquid jet, and a control device ( 8th ), characterized in that the cleaning device ( 7 ) during their operation the direction and / or intensity of the at least one liquid jet changes and to be cleaned components of the condensation dryer ( 1 ) are acted upon with the at least one liquid jet.

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