DE102012209826A1 - Condensation dryer with a pump and method 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 a heater 4 for heating the process air, a heat exchanger 5, 15 for cooling the process air after passing through the drying chamber 3 and a fan 6 for the conveying of the process air, a control device 10, a condensate tray 7 and a pump 9 driven by an electric motor 8 for conveying an aqueous liquid 33 originating from the condensate tray 7, the electric motor 8 used to operate the pump 9 being a BLDC motor. The invention also relates to a method of operating this condensation dryer.

Description

The invention relates to a condensation dryer and a method for its operation. The invention relates in particular to a condensation dryer with a drying chamber for laundry items 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, a control device , a condensate tray and a pump driven by an electric motor for conveying an aqueous liquid originating from the condensate tray, and a preferred method for its operation.

A condensation dryer is a tumble dryer whose operation is based on the condensation of moisture from wet laundry items evaporated by means of warm air (so-called "process air"). For this purpose, the process air is passed through a fan via a heater in a wet laundry containing drum as a drying chamber. The hot air absorbs moisture from the laundry to be dried. After passage through the drum, the then moist process air is passed into a heat exchanger, which is usually preceded by a lint filter. In the heat exchanger (for example air-to-air heat exchanger, heat sink of a heat pump), the moist process air is cooled, so that the water contained in the moist process air is condensed and initially collected in a condensate tray. The condensed water is then usually collected in a suitable condensate tank and the cooled and dried air in general ("circulating air dryer") again fed to the heater and then the drum.

A condensation dryer (hereinafter also abbreviated to "dryer") thus does not emit exhaust air laden with moisture, which should not be discharged into the interior of a building like a classic exhaust air dryer, and does not require an exhaust hose for discharging this exhaust air from a building. It can therefore be used in an internal bathroom or a laundry room of a larger residential complex. However, there are also known exhaust air dryer with a separation of condensate in a heat exchanger.

The process air entrains lint contained in the laundry items to be dried when passing through the drying chamber. Larger lint can be retained in the lint filter. However, a large part of the finely divided fluff passes through the lint filter and settles in the process air duct. The deposit of fluff is particularly pronounced in the heat exchanger, where condensate is due to the cooling of the moist, warm process air. The separated lint hinder the process air flowing through the heat exchanger and also affect the heat exchange. This can decrease the efficiency of the condensation dryer and increase its susceptibility to failure.

Often, the heat exchanger is removable, especially if it is designed as an air-to-air heat exchanger. The heat exchanger can then be removed from the condensation dryer for cleaning and, after a removal of adhering lint, for example by rinsing with water, be reinserted into the dryer. However, this is not possible if a heat sink of a heat pump is used as a heat exchanger, since the components of a heat pump in the condensation dryer are usually firmly connected to each other.

Therefore, condensation dryers have been developed with an internal cleaning capability for the heat exchanger. In order to achieve a sufficient cleaning effect, it is known to direct the collected condensate gushing through the heat exchanger to clean it.

The DE 199 43 125 A1 discloses a method for cleaning a portion of a guide of a process air stream in a domestic laundry dryer, wherein outside a drying phase in which produced by a blower, the process air flow and brought into the 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 with a liquid for a certain period of time. A measure of the degree of contamination of a portion of the process air duct, for example a temperature difference between the incoming and outgoing process air or between the incoming and outgoing cooling air, can be detected and automatically initiated a cleaning phase when a threshold is exceeded.

The DE 37 38 033 A1 describes a device for monitoring the degree of flow of a trained as a heat exchanger condensate separator in a domestic tumble dryer. For this purpose, a respective temperature sensor for the cooling medium are arranged at the entrance of the cooling channels in the heat exchanger and at the exit from the heat exchanger and connected in a comparison circuit in which the difference of the electrical values equivalent to the measured temperatures is comparable as a difference signal with an electrical reference signal ,

The DE 37 38 031 A1 relates to a method and apparatus for removing lint from a condensate separator formed as a heat exchanger of a clothes dryer. For controlling the lint, a display device having a threshold circuit for the heat exchanger may be used, which functions when a degree of flow is exceeded and the efficiency of the heat exchanger decreases.

The EP 0 709 516 B1 describes an announcement device for the request for cleaning a condenser in a tumble dryer, the at least one mechanical memory, a non-volatile electronic memory, means for incrementing the non-volatile memory and reporting means, wherein the increment means the content of the non-volatile memory increment each drying cycle as long as the mechanical accumulator has not stored a pull-out and reinsertion of the condenser in the tumble dryer. The non-volatile memory is reset to zero each time the capacitor is inserted. The notification means request to clean the capacitor as soon as the content of the non-volatile memory reaches a given value N.

The DE 10 2008 006 347 A1 describes a condensation dryer with a drying chamber for objects to be dried, a process air duct in which a heating 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 is a controller and first means to detect a need for cleaning the heat exchanger. As such a first means, in particular, a clock is present, which determines a total duration t _sum of previously performed drying processes and compares with a predetermined limit duration t _lim , and / or the condensation dryer comprises an evaluation unit that determines a total amount M of previously dried laundry items and with a predetermined limit total amount M _lim compares.

The WO 2009/095316 A1 and the DE 10 2008 006 349 A1 describe a condensation dryer with a process air duct, a heat exchanger and a condensate pan, wherein in the condensate pan in contact with the process air in the process air duct, a level sensor is arranged.

The cleaning of a heat exchanger of a condensation dryer and also a previously determined determination of a cleaning requirement are thus associated with a great effort. However, if a timely cleaning of the heat exchanger is omitted, it may lead to a deterioration of the efficiency of the condensation dryer or even to failure up to a failure of the condensation dryer and repair may be required.

For efficient cleaning of a heat exchanger, a cleaning method adaptable to the degree of soiling would be desirable, in particular one in which flushing with an aqueous liquid would be improved.

Against this background, the object of the present invention was to provide a condensation dryer in which cleaning of components of the condensation dryer with an aqueous liquid can be carried out more flexibly and efficiently. In particular, the invention is intended to allow lint-contaminated components of the condensation dryer, e.g. a heat exchanger can be cleaned in an improved manner using condensate from a condensate tray of the condensation dryer.

The solution of this object is achieved according to this invention by a condensation dryer (herein also abbreviated to "dryer") with the features of the corresponding independent claim and the method of the corresponding independent claim. Preferred embodiments of the condensation dryer according to the invention and of the method according to the invention are listed in corresponding dependent claims. Preferred embodiments of the method according to the invention correspond to preferred embodiments of the dryer 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 laundry items 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 A controller, a condensate pan, and a pump driven by an electric motor for conveying an aqueous liquid originating from the condensate pan, wherein the electric motor used to operate the pump is a BLDC motor.

A condensate tray is understood herein to mean, in particular, a three-dimensional body that is located below the heat exchanger and that can collect condensate that accumulates during the heat exchange with the moist, warm process air in the process air channel. Under a condensate tank used in embodiments of the invention is in Generally understood a vessel into which the condensate initially collected in the condensate pan for collection, especially for temporary storage before re-use for cleaning, is promoted.

In a preferred embodiment of the condensation dryer, the pump is arranged in a condensate channel between the condensate tray and a component of the condensation dryer to be cleaned. If the condensate is collected in a condensate tank, the pump is preferably arranged between the condensate tank and the component to be cleaned. It may be advantageous that between the condensate tray and the condensate tank, a further pump for conveying condensate from the condensate tray is arranged.

Hereinafter, for the condensate or a "condensate pan-derived aqueous liquid", which may also be a mixture of condensate with tap water, the term "flushing liquid" is also used.

"Carriage of an aqueous liquid from the condensate tray" herein means, in particular, transport of the aqueous liquid originating from the condensate tray to a component to be cleaned, which is generally followed by contacting and purifying the component to be cleaned.

If present in the condensation dryer, the condensate tank may be fixed or removable in the condensation dryer. If the condensate container is removable, a user of the condensation dryer can easily use the consumed, i. with a large amount of lint etc. contaminated, dispose of rinse liquid. Otherwise, an excessively dirty rinse liquid should be pumped out of the condensation dryer by a suitable device. This can be done for example by means of the pump directly or via the condensate tray.

When referring herein to a component to be cleaned, it is meant in particular the heat exchanger and / or a lattice grate. According to the invention, the component to be cleaned can be cleaned with an aqueous liquid originating from the condensate tray. Here, as a rinsing liquid, condensate per se or a mixture of condensate with a condensation dryer from outside the condensation dryer, e.g. be used by an external water supply, supplied aqueous liquid, in particular tap water. In this case, the condensate originate directly from the condensate tray or initially stored in a condensate tank. Accordingly, for example tap water can be mixed as an aqueous liquid directly with the condensate and the mixture can be used as a rinsing liquid for cleaning. Alternatively, a mixture of condensate and tap water can be produced or temporarily stored in the condensate tank before it is used as flushing liquid in one embodiment of the process according to the invention.

Preferably, the condensation dryer is therefore connectable to an external water supply, so that an aqueous liquid from the external water supply, in particular tap water, can be mixed with the condensate.

In a preferred embodiment of the invention, a sensor for the state of purity of the condensate is present in the condensate channel. In this case, it is preferably provided that if the proportion of impurities, for example fluff, is too high, an amount of tap water corresponding to this proportion is added to the condensate for dilution before it is used as flushing fluid in the meaning of the invention. According to the invention may also be provided that the condensate is disposed of on reaching an upper limit A _lim for the proportion of impurities.

In the condensation dryer according to the invention, at least one heat exchanger is present as a component preferably to be cleaned. The heat exchanger is in particular an air-air heat exchanger or a heat sink, in particular an evaporator, a heat pump. A heat pump is characterized by two heat exchangers, namely a heat sink, in which heat is absorbed, a heat source in which heat is released, and a pumping device, which transfers heat from the heat sink to the heat source optionally with a change in temperature. In a condensation dryer equipped with a heat pump of the compressor type, the cooling of the warm, moisture-laden process air takes place essentially in the heat sink of the heat pump, also referred to as evaporator, where the heat transferred is used to evaporate a refrigerant circulating in the pump device designed as a circuit , The refrigerant vaporized due to the heating is supplied in the pump device via a compressor of the heat source, which is a condenser for the refrigerant, the heat pump, where due to the liquefaction of the gaseous refrigerant heat is released, which is used to heat the process air before entering the drying chamber, usually a drum, is used. Behind the condenser, the now liquid refrigerant is in a throttle of the pumping device relaxed, whereby its internal pressure is lowered, and finally comes back to the evaporator.

In the condensation dryer according to the invention is in the process air duct in any case preferably an air-to-air heat exchanger or an evaporator of a heat pump, more preferably an evaporator of a heat pump.

A BLDC motor used in the condensation dryer according to the invention is generally a brushless DC motor (Brushless DC motor), in which in particular the otherwise conventional mechanical commutator with brushes for current application is replaced by an electronic drive circuit. Usually in BLDC motors, the rotor is realized with a permanent magnet. In this case, the fixed stator usually comprises coils which are controlled offset in time by an electronic circuit to produce a rotating field, which generates a torque at the permanently excited rotor. With BLDC motors it is possible to make the electronic commutation dependent on the rotor position, the rotor speed and the torque. In this case, a sensor-controlled and a sensorless commutation are used to detect the rotor position and speed. Another term for the motor generally described herein as a BLDC motor is PMS motor, where "PMS" is an abbreviation for the English term "Permanent Magnet Synchronous" and thus to both the permanent magnet rotor of the motor and the design indicates the motor as a synchronous motor.

In any case, the use of a BLDC motor as a drive motor for the pump allows a change in the speed in a simple manner and in particular a high speed. Thus, by using a BLDC motor, a very flexible and efficient implementation of the inventive method discussed below is possible. In addition, it has been found that with a BLDC motor under otherwise identical operating conditions, in particular the same speed, a higher energy efficiency compared to other electric motors can be achieved.

Preferably, the condensation dryer has means for detecting the cleaning requirement of components to be cleaned. This allows a particularly efficient use of the dryer according to the invention and an efficient implementation of the method described in detail below for its operation.

In a preferred embodiment, the condensation dryer as a means for detecting the cleaning requirement on a clock, which determines a total duration t _sum of previously performed drying processes and compares with a predetermined limit duration t _lim , and / or the condensation dryer has as means for detecting the cleaning need an evaluation on, which determines a total amount M of previously dried laundry items and compared with a predetermined limit total amount M _lim . In this case, the type of garments can be taken into account, which can be done for example via an automatic determination of the type of laundry or a setting on the condensation dryer by a user.

In a further preferred embodiment, the condensation dryer as a means for detecting the cleaning requirement to a counter, which determines the number n of the already carried out drying processes and compared with a predetermined limit number n _lim . This counter can preferably be reset when cleaning the heat exchanger is performed.

When reaching or exceeding t _lim , M _lim or n _{lim, there} would then be a need for cleaning.

Alternatively or additionally, the condensation dryer as a means for detecting the need for cleaning in the process air duct having a first temperature sensor and a second temperature sensor, which are arranged on opposite sides of the heat exchanger and by comparing a difference .DELTA.T measured temperatures with a predetermined limit for the Temperature difference .DELTA.T _lim allow a determination of the cleaning requirement.

Is in the condensation dryer according to the invention as a means for detecting the need for cleaning a clock available, 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 a cleaning of the heat exchanger is performed.

If the condensation dryer according to the invention comprises an evaluation unit which determines a total quantity M of previously dried laundry items and compares them with a predetermined total limit quantity M _lim , the value for the total quantity M can preferably be reset when a cleaning of the heat exchanger is carried out ,

The methods for detecting a need for cleaning can be used, for example, both for a heat exchanger and for a lint filter as a component to be cleaned.

The condensation dryer generally has a nozzle, since the rinsing liquid is generally passed through a suitable nozzle to the component to be cleaned of the condensation dryer. For example, a nozzle can extend over the entire width of a heat exchanger and, for example, have a length of 200 mm with a 2 mm wide nozzle gap. However, the invention also makes it possible in particular to use significantly smaller nozzles, for example with a circular outlet opening with a diameter of a few mm, in particular less than 2 mm. Due to the higher jet pressures possible with the present invention, blockage of even small nozzles can generally be avoided or eliminated quickly.

In a preferred embodiment, the dryer also has an acoustic and / or visual display device for different states of the dryer. For this purpose, an optical display device is preferably used. The display device can give information about the operation of the dryer, for example, by the output of a text or by lighting different colored light emitting diodes, for example via the course of a method according to the invention and / or the display of a cleaning requirement. If necessary, the need for cleaning can be quantified.

In a preferred embodiment, the condensation dryer therefore has an acoustic and / or visual display device for indicating a cleaning requirement and / or for indicating the execution of a cleaning process.

In a very particularly preferred embodiment of the invention is monitored in the condensation dryer, whether sufficient rinsing liquid, in particular condensate, is present for a rinse of components to be cleaned.

Preferably, a fill level sensor is therefore arranged in the condensate tray of the condensation dryer and in embodiments in which a condensate container is used, in the condensate container or in both. As long as the described purpose is fulfilled, the level sensor to be used in embodiments of the invention is not limited. According to the invention, it has proved to be advantageous to use a device comprising a reed contact as fill level sensor. Preferably, a permanent magnet float is used in conjunction with a reed contact as fill level sensor. In this case, the reed contact in contact with the permanent magnetic float in the condensate tray close a circuit.

In this case, it is preferably stored in the control device that the pump is only put into operation if there is a predetermined minimum liquid level d _min in the condensate tray and / or possibly a condensate container. The conveyance of rinsing liquid or condensate can thereby be made dependent on the presence of a sufficient amount in the condensate tray or the condensate container. In addition to the use of a level sensor, the water flow in the intake of the pump can be designed appropriately. This is preferably designed such that even at a maximum flow rate of the pump, the flow of the aqueous liquid during pumping can not tear off. This means that a sufficiently large volume of condensate or rinsing liquid is advantageously present in the intake area of the pump.

Preferably, the condensation dryer according to the invention for this embodiment, an optical and / or acoustic display means for falling below a predetermined minimum level h _min in the condensate pan.

In one embodiment of the invention, the control of the pump may be accomplished by causing an inverter in the BLDC motor to fluctuate in response to a changing motor current and thus to a low liquid level, i. too small an amount of flushing liquid, recognizes. Depending on the changes in the motor current predetermined in the control device for this purpose, it may then be provided that the operation of the pump, i. the conveying operation is stopped or interrupted for a predetermined period of time.

The condensation dryer according to the invention can be configured as an exhaust air dryer or as a circulating air dryer. In a recirculating air dryer, the process air is circulated in a closed circuit. In a vented dryer, however, the process air is fed as so-called supply air from a supply air access to the drum and after leaving the drum and passed through the heat exchanger as exhaust air to an exhaust outlet.

According to the invention, it is preferred if process air and cooling air or process air and refrigerant of a heat pump are each guided through the corresponding heat exchangers in a crossflow or countercurrent process.

The heater in the dryer according to the invention may be, for example, an electric heater or a gas heater. As the degree of drying of the clothes to be dried in the condensation dryer decreases the energy required for drying, the Heating regulated accordingly, ie with increasing degree of drying their heat output reduced.

• (a) ein Kondensat in der Kondensatwanne unter Einsatz der vom BLDC-Motor angetriebenen Pumpe zur Reinigung einer Komponente des Kondensationstrockners befördert wird, und
• (b) das Kondensat mit der Komponente in Kontakt gebracht wird.

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 located, a control device, a condensate pan, a pump driven by an electric motor for conveying an originating from the condensate pan aqueous fluid in a condensate channel, wherein the electric motor used to operate the pump is a BLDC motor and

• (a) a condensate in the condensate pan is conveyed using the pump driven by the BLDC motor to clean a component of the condensation dryer, and
• (B) the condensate is brought into contact with the component.

In particular, the rotational speed of the BLDC motor can be set in a wide range in the above-described step (a).

The steps (a) and (b) are preferably carried out before or after a drying process has been carried out. In this case, a drying process is characterized in particular in that the heating is switched on to heat the process air.

In a preferred embodiment, the method comprises in a rinsing program a step (a) with several sections (a _i ), in which the pump is switched off and / or a delivery rate of the pump is different.

The method, in particular the rinsing program, is preferably carried out with regard to a determined cleaning requirement of components to be cleaned.

In the method according to the invention preferably a step of qualitative or quantitative determination of a cleaning requirement of components of the condensation dryer is provided, as a means for detecting the cleaning requirement, for example, a clock is present, which determines a total duration t _sum of previously performed drying processes and with a predetermined limit duration t _lim compares, and / or the condensation dryer as means for detecting the cleaning requirement comprises an evaluation unit which determines a total amount M of previously dried laundry items and compared with a predetermined limit total amount M _lim . In this case, the means for determining the cleaning requirement for the heat exchanger determine a degree of use U, compare it with a predetermined value U _lim and set when reaching U _lim , ie under the condition U _lim = U, the cleaning requirement.

The type and size of the usage measure U and of the predetermined value U _lim depend on the type of the first funds used. If the first means is a 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. In the case U = U _lim , a need for cleaning is determined and the cleaning program initiated.

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

A cleaning requirement or a cleaning time can also be determined by monitoring the temperature of the process air as a function of the duration of a drying process. Here, in one embodiment, the occurrence of comparatively high temperatures can be seen as indicative of a lint-laden and therefore compromised in its heat exchange efficiency air-to-air heat exchanger.

Finally, it can also be automatically provided by the choice of a specific drying process, which is aimed, for example, at a drying of a particular type of laundry such as cotton or synthetic, that subsequent to the drying process by the control device automatically predetermined rinsing process is performed.

It is preferred according to the invention that the cleaning requirement for e.g. the heat exchanger is acoustically and / or visually displayed. 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.

If a determination of the cleaning requirement for one or more components of the condensation dryer is provided, these are or will be subsequently to the qualitative or quantitative determination of the cleaning requirement subjected to a method according to the invention and generally cleaned. Preferably, a cleaning of the heat exchanger is performed. The cleaning can be carried out automatically or by a user of the condensation dryer controllable. For this purpose, it is preferably possible to set on the condensation dryer whether a cleaning or a cleaning step should be carried out automatically or manually.

The rinsing liquid used in the process according to the invention generally comprises condensate containing more or less large quantities of an aqueous liquid, such as e.g. Tap water may be added. To improve the cleaning effect, additives such as other solvents (for example alcohols) or surface-active reagents may be added to the rinsing liquid.

The cleaning programs are basically not limited, as long as sufficient cleaning of the heat exchanger is achieved. Thus, the cleaning programs can differ in terms of quantity, temperature and flow rate of the washing liquid.

In a preferred embodiment of the invention, an amount of a rinsing liquid required as a function of a predetermined cleaning program is determined, compared with the amount of rinsing liquid present in a storage container, and an undershooting of the required quantity is indicated acoustically and / or visually.

According to the invention, a selected drying process may be assigned specific speed ranges or rotational speeds of the BLDC motor used to operate the pump.

Advantageously, during the method according to the invention, the speed of the BLDC motor used can be varied in a predetermined manner and an efficient cleaning can be achieved via a corresponding variation of the flow rate of the rinsing liquid, generally expressed as volume per (time times line or nozzle cross-section) ,

In a preferred embodiment, at the beginning of a cleaning program, a high flow rate may be selected, which then decreases to eventually increase again. Such variations in flow rate can be repeated.

In extreme cases, a pulsating operation can be carried out in which the pump is operated according to a high flow speed over a predetermined first period, but in a second period the pump is turned off. Subsequently, the pump is operated again according to a high flow rate for a predetermined third period.

Thus, contaminants on a component to be cleaned, e.g. Fluff, first dissolved or softened, and then subsequently removed with another flow pulse.

If it turns out that the rinsing liquid used is too contaminated, water can be supplied from an external water supply or the rinsing liquid can be disposed of. The quality of the aqueous liquid to be used is preferably determined by means of a suitable sensor, e.g. an optical sensor such as a turbidity sensor.

In the method according to the invention, it is preferred that the rinsing liquid is passed into the heat exchanger, then collected in a condensate tray and then pumped back into the condensate channel. In the method, it may be predetermined that such a cycle is run through more than once, so that, for example, a cycle of the rinsing liquid results for a given period of time.

After completion of the cleaning steps, the user in the embodiment of the condensation dryer with a removable condensate container can manually dispose of the rinsing liquid by removing and emptying the condensate container. Alternatively, the rinsing liquid can be disposed of automatically, for example via a drain hose from the condensation dryer. It is possible that the flushing liquid is pumped out of the condensate pan directly through a suitable pump and disposed of.

In a preferred embodiment of the method according to the invention, the condensate is first collected in a condensate container. In this case, the pump driven by a BLDC motor is preferably arranged between the condensate container and the component to be cleaned. The optional mixing of water from an external water supply can be done directly by connecting a water supply line with the condensate channel or by adding or introducing additional water into the condensate tank.

The invention has surprising advantages, in particular in a condensation dryer with an internal cleaning option. The use of a BLDC motor allows, in particular by generating higher shear forces, a better cleaning effect of components to be cleaned a condensation dryer. In addition, a cleaning can be variably adjusted to a cleaning requirement or soiling state of these components, both in terms of the frequency and the intensity of the cleaning. This is especially true in a comparison with the application of a surge-like water flow, as in the so-called falling-stream principle.

Finally, the invention also allows the use of a plurality of different nozzles, particularly nozzles that differ significantly in the size of their orifice (nozzle orifice geometries), since, due to the higher flow rate of the rinse liquid possible with the present invention, i. Jet pressures, a blockage can be avoided or eliminated.

In embodiments, the invention has the advantage that in the case of a condensation dryer, without the necessity of opening it, both a need for cleaning of components can be determined and efficient cleaning can be carried out. In a simple and efficient way can be cleaned automatically or by influencing a user, for example, the heat exchanger or the lint filter of the condensation dryer. This is particularly advantageous when using a heat pump, since the evaporator of a heat pump for cleaning can not be removed from the condensation dryer. 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. 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.

Further details of the invention will become apparent from the following description of three non-limiting embodiments of the condensation dryer according to the invention and a method for operating this condensation dryer. Reference is made to the figures of the accompanying drawings.

1 shows a vertical section through a first embodiment of a condensation dryer, which is designed as a circulating air dryer with an air-to-air heat exchanger.

2 shows a vertical section through a second embodiment of a condensation dryer, which is also designed as a circulating air dryer with an air-to-air heat exchanger.

3 shows a vertical section through a third embodiment of a condensation dryer, which is designed as a circulating air dryer with a heat pump and in particular with an evaporator as a heat sink.

In the 1 to 3 each of the long arrows indicates the flow direction of the process air.

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 during a drum rotation. The process air is in the process air duct 2 by means of a blower 6 via an electric heater 4 through the drum 3 guided. It is by the electric heater 4 heated air from behind, ie from the one closing the filling door 22 opposite side of the drum 3 through whose perforated bottom into the drum 3 directed. The heated process air thus enters the drum 3 , where in 1 Moist laundry items not shown are deprived of moisture.

After leaving the drum 3 the process air laden with moisture flows in the process air duct 2 through a lint filter 16 inside the door 22 , Subsequently, the process air flow in the door 22 deflected down and to an 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 7 collected.

That in the condensate tray 7 Trapped condensate or the aqueous liquid 33 is via a condensate channel 23 in which there is a pump 9 located by a BLDC motor (Brushless DC motor) 8th is driven, for cleaning on the air-to-air heat exchanger 5 directed.

In the embodiment shown here is an external water supply 21 via a water supply pipe 20 to the condensate channel 23 connected. This allows a mixture of condensate with tap water to achieve a desired low level of contamination in the flushing liquid 33 to achieve. In addition, a lack of available condensate can be compensated in this way.

The used rinsing liquid 33 (condensate used for cleaning, if necessary diluted with tap water) can, if necessary because of the contamination, be disposed of via a line not shown to the outside of the device.

To determine a need for cleaning, the condensation dryer 1 a first temperature sensor 29 in front of the air-to-air heat exchanger 5 and a second temperature sensor 30 after the air-air heat exchanger 5 on. For a clean air-to-air heat exchanger 5 The heat exchange takes place very efficiently, so that the process air when passing through the air-to-air heat exchanger 5 cools strongly. Is however the air-air heat exchanger 5 contaminated by the deposition of lint leaves the efficiency of the air-to-air heat exchanger 5 to. In this case, the process air cools when passing through the air-to-air heat exchanger 5 not so strong anymore. As a result, in the case of a contaminated air-to-air heat exchanger 5 a reduced temperature difference ΔT between the first temperature sensor 29 and the second temperature sensor 30 detected.

To cool the moist, warm process air flows in a cooling air duct 32 in the air-to-air heat exchanger 5 from a cooling air inlet 26 up to a cooling air outlet 31 Cooling air. To transport the cooling air is in the cooling air duct 32 a cooling air blower 27 arranged.

At the in 1 shown embodiment are as a means for determining a cleaning requirement of the air-to-air heat exchanger 5 also a counter 37 for the number of drying processes carried out, one o'clock 11 and an evaluation unit 17 available. These are either part of the control device 10 of the condensation dryer 1 or her assigned.

In case of determined need for cleaning is in the in 1 shown embodiment of the air-air heat exchanger 5 possibly with water from the water supply line 20 mixed condensate 33 cleaned as rinsing liquid. The rinsing liquid 33 thus comprises condensate previously in the air-to-air heat exchanger 5 and from the condensate tray 7 by means of the pump 9 via a condensate channel 23 in the air-to-air heat exchanger 5 is pumped. After passing through the air-to-air heat exchanger 5 becomes the rinsing fluid 33 in the condensate tray 7 collected and can through the condensate channel 23 back to the heat exchanger 5 be pumped. This cycle can be repeated several times until a desired cleaning is achieved.

The drum 3 will be in the in 1 shown embodiment on the rear floor by means of a pivot bearing and front by means of a bearing plate 35 stored, with the drum 3 with a brim on a sliding strip 36 on the bearing plate 35 rests and is held at the front end. The control of condensation dryers 1 via a control device 10 by the user via a control unit 24 can be regulated.

At the in 1 In the embodiment shown, the blower 6 and the drum 3 by a drive motor 28 driven.

For monitoring the fluid level in the condensate tray 7 is in this a level sensor 19 appropriate.

The short thick arrow indicates the flow direction of the cooling air.

2 shows a vertical section through a condensation dryer 1 according to a second embodiment, which is designed as a circulating air dryer. As for the first embodiment of 1 the cooling of the warm, moisture-laden process air takes place from the drum 3 in the air-to-air heat exchanger 5 by heat exchange with cooling air in a cooling air duct 32 , In the cooling air duct 32 there is a cooling air blower 27 , which cooling air from a cooling air inlet 26 through the air-to-air heat exchanger 5 through to the cooling air outlet 31 promoted.

At the in 2 shown second embodiment of a condensation dryer, the determination of a cleaning requirement for the air-to-air heat exchanger 5 as well as its cleaning as for 1 shown.

In the following, particular attention will be paid to differences to those in 1 shown embodiment received. Otherwise, like reference numerals refer to like components that, unless otherwise indicated, have the same functions as in FIG 1 describe described.

At the in 2 shown second embodiment, the condensate 33 with a pump not shown in the condensate channel 23 and then into a condensate tank 34 pumped where the condensate 33 can be cached before further use. For cleaning the air-to-air heat exchanger 5 becomes the condensate 33 then by means of a BLDC motor 8th driven pump 9 in the air-to-air heat exchanger 5 pumped. In this case, the number of revolutions of the BLDC motor 8th be varied within a wide range, so that the dependent on the pump capacity 9 and thus the achieved flow rate of the condensate 33 to a detected level of pollution of the air-to-air heat exchanger 5 can be adjusted. As a result, cleaning of the air-to-air heat exchanger can be efficiently performed 5 be reached by lint, etc. In the second embodiment of a condensation dryer according to the invention shown here is for flushing the air-to-air heat exchanger 5 only condensate 33 used. This can result in an unacceptable level of contamination according to one of the art and Amount of the laundry items dependent period to be disposed of in a manner not shown here.

3 shows a vertical section through a condensation dryer 1 according to a third embodiment, which is designed here as a circulating air dryer and as a heat exchanger 15 the evaporator of a heat pump 12 . 13 . 14 . 15 having. The short arrows with unfilled arrowhead indicate the flow direction of the refrigerant. Otherwise, the in 3 Parts shown with the same reference numerals the same meaning as in 1 and 2 ,

The moist, warm process air leaves the drum 3 over a lint filter 16 and flows in the process air duct 2 to the evaporator 15 the heat pump, where it is cooled. In the evaporator 15 becomes one in the heat pump cycle 12 . 13 . 14 . 15 circulating refrigerant evaporates and through a compressor 13 a liquefier 12 fed, where the refrigerant passes under heat to the flowing in the process air duct cooled and dehumidified process air back into the liquid state. The refrigerant in liquid form is supplied via a throttle valve 14 turn to the evaporator 15 passed, whereby the refrigerant circuit is closed.

That in the evaporator 15 accumulating condensate 33 is in a condensate tray 7 collected and with the help of a pump not shown here in a condensate channel 23 first in a condensate tank 34 pumped. From the condensate tank 34 The cached condensate is as a rinsing liquid 33 with the help of a pump 9 that is targeted via a BLDC motor 8th operated, for cleaning lint, etc. by the evaporator 15 passed and finally enters the condensate tray 7 , From the condensate tray 7 can the condensate 33 by means of the pump 9 over the condensate channel 23 back into the condensate tank 34 be pumped. This cycle can be repeated if necessary.

In the condensate tray 7 there is a level sensor 19 , which is designed here as a reed contact in conjunction with a permanent magnetic float. The level sensor 19 allows for the controller 10 a statement as to whether sufficient condensate is present for carrying out a process according to the invention.

18 means an optical and / or acoustic display device for an indication of the presence of a predetermined minimum level h _min in the condensate tray 7 and / or canceling a drying process.

Also at the in 3 shown third embodiment, the blower 6 and the drum 3 through the engine 30 driven.

LIST OF REFERENCE NUMBERS

1

 condensation dryer

2

 Process air duct

3

 drying chamber

4

 heater

5

 Air-air heat exchanger

6

 fan

7

 Drain pan

8th

 Electric motor; BLDC motor

9

 pump

10

 control device

11

 Clock

12

 Condenser of a heat pump

13

 Compressor of a heat pump

14

 throttle valve

15

 Evaporator of a heat pump

16

 lint

17

 evaluation

18

 Display device, optical and / or acoustic

19

 level sensor

20

 Water supply line

21

 External water supply

22

 door

23

 condensate channel

24

 operating unit

25

 laundry agitator

26

 Cooling air inlet

27

 Cooling fan

28

 Drive motor for blower and drum

29

 First temperature sensor

30

 Second temperature sensor

31

 Cooling air outlet

32

 Cooling air duct

33

 Aqueous liquid, condensate

34

 Condensate tank, storage tank

35

 end shield

36

 lubricating strip

37

 counter

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 19943125 A1 [0007]
• DE 3738033 A1 [0008]
• DE 3738031 A1 [0009]
• EP 0709516 B1 [0010]
• DE 102008006347 A1 [0011]
• WO 2009/095316 A1 [0012]
• DE 102008006349 A1 [0012]

Claims (15)

Condensation dryer ( 1 ) with a drying chamber ( 3 ) for laundry items to be dried, a process air duct ( 2 ), in which a heating ( 4 ) for heating the process air, a heat exchanger ( 5 . 15 ) for cooling the process air after passing through the drying chamber ( 3 ) and a blower ( 6 ) for the transport of the process air, a control device ( 10 ), a condensate tray ( 7 ) and one of an electric motor ( 8th ) driven pump ( 9 ) for transporting one of the condensate tray ( 7 ) derived aqueous liquid ( 33 ), characterized in that the operation of the pump ( 9 ) used electric motor ( 8th ) is a BLDC motor. Condensation dryer ( 1 ) according to claim 1, characterized in that the pump ( 9 ) in a condensate channel ( 23 ) between the condensate tray ( 7 ) and a component to be cleaned ( 5 . 15 . 16 ) of the condensation dryer ( 1 ) is arranged. Condensation dryer ( 1 ) according to claim 2, characterized in that the component to be cleaned ( 5 . 15 . 16 ) the heat exchanger ( 5 . 15 ) and / or a lattice grid ( 16 ). Condensation dryer ( 1 ) according to one of claims 1 to 3, characterized in that it comprises means ( 10 . 11 . 17 . 37 ) for detecting the cleaning requirement of components to be cleaned ( 5 . 15 . 16 ) having. Condensation dryer ( 1 ) according to claim 4, characterized in that it serves as an agent ( 10 . 11 . 17 . 37 ) to detect the need for cleaning a clock ( 11 ), which determines a total duration t _sum of previously performed drying processes and compares with a predetermined limit duration t _lim , and / or the condensation dryer ( 1 ) as a means ( 10 . 11 . 17 . 37 ) to identify the need for cleaning an evaluation ( 17 ), which determines a total amount M of previously dried laundry items and compares them with a predetermined total limit amount M _lim . Condensation dryer ( 1 ) according to claim 4, characterized in that it serves as an agent ( 10 . 11 . 17 . 37 ) to detect the need for cleaning a counter ( 37 ), which determines the number n of drying processes already carried out and compares them with a predetermined limit number n _lim . Condensation dryer ( 1 ) according to claim 4, characterized in that the condensation dryer ( 1 ) as a means ( 10 . 11 . 17 . 37 ) for detecting the cleaning requirement in the process air duct ( 2 ) a first temperature sensor ( 29 ) and a second temperature sensor ( 30 ), which on opposite sides of the heat exchanger ( 5 . 15 ) Are arranged and permit by comparing a difference .DELTA.T of the measured temperatures of them with a predetermined limit value for the temperature difference .DELTA.T _lim a determination of the cleaning requirement. Condensation dryer ( 1 ) according to one of claims 1 to 7, characterized in that it comprises an acoustic and / or visual display device ( 18 ) for indicating a cleaning requirement and / or for indicating the execution of a cleaning process. Condensation dryer ( 1 ) according to one of claims 1 to 8, characterized in that in the condensate tray ( 7 ) a level sensor ( 19 ) is arranged. Condensation dryer ( 1 ) according to one of claims 1 to 9, characterized in that it via a water supply line ( 20 ) to an external water supply ( 21 ) is connectable, so that an external aqueous liquid from the external water supply ( 21 ) with the condensate ( 33 ) can be mixed. Condensation dryer ( 1 ) according to one of claims 1 to 10, characterized in that in the process air channel ( 2 ) as a heat exchanger ( 5 . 15 ) an air-to-air heat exchanger ( 5 ) or an evaporator ( 15 ) a heat pump ( 12 . 13 . 14 . 15 ) is located. 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 ) for cooling the process air after passing through the drying chamber ( 3 ) and a blower ( 6 ) for the transport of the process air, a control device ( 10 ), a condensate tray ( 7 ) and one of an electric motor ( 8th ) driven pump ( 9 ) for conveying an aqueous liquid originating from the condensate tray ( 33 ) in a condensate channel ( 23 ), whereby the operation of the pump ( 9 ) used electric motor ( 8th ) is a BLDC motor, characterized in that (a) a condensate in the condensate tray ( 7 ) using the pump driven by the BLDC motor ( 9 ) for cleaning a component ( 5 . 15 . 16 ) of the condensation dryer ( 1 ) and (b) the condensate with the component ( 5 . 15 . 16 ) is brought into contact. A method according to claim 12, characterized in that the steps (a) and (b) are carried out before or after carrying out a drying process. A method according to claim 12 or 13, characterized in that in a washing program step (a) comprises a plurality of sections (a _i ) in which the pump ( 8th ) is switched off and / or a delivery rate of the pump ( 8th ) is different. Method according to one of claims 12 to 14, characterized in that a rinsing program is carried out with regard to a determined cleaning requirement.

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