WO2013186114A1

WO2013186114A1 - Condensation dryer with a pump and method for operation thereof

Info

Publication number: WO2013186114A1
Application number: PCT/EP2013/061702
Authority: WO
Inventors: Kai Nitschmann
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2012-06-12
Filing date: 2013-06-06
Publication date: 2013-12-19
Also published as: DE102012209826A1

Abstract

The invention relates to a condensation dryer 1 having: a drying chamber 3 for objects to be dried; a process air channel 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 conveying the process air are located; a control device 10; a condensate tub 7 and a pump 9 driven by an electric motor 8, for conveying an aqueous fluid 33 originating from the condensate tub 7, wherein the electric motor 8 used for operating the pump 9 is a BLDC motor. The invention also relates to a method for operating this condensation dryer.

Description

Condensation dryer with a pump and method for its operation

The invention relates to a condensation dryer and a method for its operation. More particularly, the invention relates 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 drier whose function is based on the condensation of moisture from damp laundry items evaporated by means of warm air (so-called "process air") .The process air is passed through a fan via a heater into a drum containing a wet laundry as a drying chamber The hot air absorbs moisture from the laundry items to be dried After passing through the drum, the moist process air is led into a heat exchanger, which is usually preceded by a lint filter in the heat exchanger (eg 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 pan The condensed water is then usually collected in a suitable condensate tank and the cooled and dried air in general n ("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 conventional exhaust air dryer and does not require an exhaust hose for discharging this exhaust air from a building can therefore be 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.

DE 199 43 125 A1 discloses a method for cleaning a section of a guide of a process air flow in a domestic laundry dryer, wherein outside of a drying phase, in which produced by means of a blower, the process air flow and is brought into the drying room in contact with the laundry to be dried, in a cleaning phase with the fan off, a portion 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 section of the process air duct, eg a Temperature difference between the incoming and outgoing process air or between the incoming and outgoing cooling air, can be detected and automatically initiated when a threshold value is exceeded, a cleaning phase.

DE 37 38 033 A1 describes a device for monitoring the degree of flow of a formed as a heat exchanger condensate separator in a household 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 ,

DE 37 38 031 A1 relates to a method and an apparatus for removing flows from a formed as a heat exchanger condensate separator 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.

EP 0 709 516 B1 describes a message requesting device for cleaning a condenser in a tumble dryer, which contains at least one mechanical memory, a nonvolatile electronic memory, means for incrementing the nonvolatile memory and signaling means, wherein the incrementing means does not control the content of the non Volatile memory increment with each drying cycle, as long as the mechanical memory has not stored a withdrawal and re-insertion of the condenser in the 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. 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 heater for heating the process air, a heat exchanger for cooling the process air after passing through the drying chamber and a fan for the Transporting the process air is located, a controller and first means for detecting 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 with a predetermined limit duration t | _im Vergleich, and / or the condensation dryer comprises an evaluation unit which determines a total amount M of previously dried laundry items and compared with a predetermined limit total amount M _Nm .

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

DE 10 2007 030 065 A1 describes a dishwasher with a conveyor for conveying rinsing liquor, wherein the conveyor has two pumps with a brushless DC motor (BLDC) and a common control electronics for the first and the second pump is provided. In brushless permanent magnet motors, the direction of rotation should be adjustable by the control electronics and the flow rate of a pump can be controlled by adjusting the speed of the stator.

DE 10 2010 029 892 A1 describes 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 a 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. EP 2 171 151 B1 describes an arrangement for automatic cleaning of air filters in a heat pump fabric drying machine, comprising at least one nozzle for injecting a liquid and at least one air filter unit, wherein the air filter unit and / or the liquid injection nozzle is mounted such that she being able to move relative to a stationary reference frame, the relative movement being effected by at least one associated actuator. For the transport of the liquid, a pump is used, for example a bidirectionally operating pump which is driven by a DC motor. 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") having the features of the corresponding independent patent claim and the method of the corresponding independent patent claim Preferred embodiments of the condensation dryer according to the invention and of the method according to the invention are 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 which is located below the heat exchanger and which can collect condensate that accumulates in the process air channel during the heat exchange with the moist, warm process air. A condensate container used in embodiments of the invention is generally understood to mean a vessel into which the condensate initially collected in the condensate tray is transported for collection, in particular for intermediate storage, before being used again for cleaning.

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.

"Transport of an aqueous liquid originating 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 cleaning 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 can be removed, a user of the condensation dryer can easily dispose of the spent, ie with a large amount of lint etc. contaminated, rinsing 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 can also be provided that the condensate on reaching an upper limit A | _is disposed of 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 temperature change. 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 expanded in a throttle of the pumping device, whereby its internal pressure is reduced, and finally passes 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, particularly 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 actuated offset in time by an electronic circuit in order to create a rotating field which produces a torque at the permanent excited rotor generated. 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 with a predetermined limit duration t | _in compares, and / or the condensation dryer has as means for detecting the need for cleaning an evaluation unit which determines a total amount M of previously dried laundry items and with a predetermined limit total amount M | _im comparing. 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 need for cleaning a counter, the number n of the already determined drying processes and compared with a predetermined limit number riiim. This counter can preferably be reset when cleaning the heat exchanger is performed.

When reaching or exceeding t | _im , M | _im or ni _im would then have 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 Wärmetau- shear and by comparing a difference ΔΤ of the measured temperatures with a predetermined limit for the temperature difference AT | _im allow a determination of the cleaning needs.

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 with a predetermined limit duration t | _im , this clock can preferably be reset when a cleaning of the heat exchanger is performed. Does the condensation dryer according to the invention as means for detecting the need for cleaning an evaluation unit that determines a total amount M of previously dried laundry items and with a predetermined limit total amount M | _In comparison, the value for the total amount M may preferably be reset when cleaning of the heat exchanger is performed.

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, a length of 200 mm with a 2 mm wide die 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.

It is preferably deposited in the control device that the pump is only put into operation when in the condensate tray and / or possibly one Condensate tank a predetermined minimum liquid level d _m in present. 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 with a maximum delivery rate of the pump, the flow of the aqueous liquid during pumping can not break 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 delivery mode is set or interrupted for a given 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 an exhaust air dryer, however, the process air is fed as so-called supply air from a supply air access to the drum and passed after leaving the drum and passage 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 items to be dried in the condenser dryer decreases the energy required for drying, the heating is appropriately regulated, ie its heat output decreases as the degree of drying progresses.

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,) 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 _Nm compares, and / or the condensation dryer as a means for detecting the cleaning requirement comprises an evaluation unit which determines a total amount M of previously dried laundry items and with a predetermined limit total amount M | _im comparing. In this case, the means for determining the cleaning requirement for the heat exchanger determine a degree of use U, compare this with a predetermined value U | _im and set when reaching U | _im , ie under the condition U | _im = U, the cleaning requirement.

Type and size of the usage measure U and the given value U | _in depend on the type of the first means 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 Uiim when using a counter is usually also a natural number. For the case U = U | _im a need for cleaning is determined and initiated the cleaning program.

Accordingly, the measured value U and the predetermined value U | _in using a clock in each case, a period At, when using two temperature sensors, a temperature difference AT and using a certain total amount M of previously dried laundry pieces each weighing.

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, by choosing a particular drying process, for example, to a drying of a particular type of laundry such as made of cotton or synthetics, be automatically provided 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 displayed acoustically and / or visually. 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 are subsequently subjected to the method according to the invention for the qualitative or quantitative determination of the cleaning requirement and are 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 to which more or less large amounts of an aqueous liquid, such as 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 is preferably assigned specific rotational 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 can be specified that Such a cycle is traversed more than once, so that, for example, results in a cycle of the rinsing liquid for a predetermined period.

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 the case of a condensation dryer with an internal cleaning option. The use of a BLDC motor allows better, in particular through the generation of higher shear forces

Cleaning effect of components to be cleaned a condensation dryer.

In addition, a cleaning variable to a need for cleaning or

Pollution state of these components, both in terms of frequency and intensity of 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, in particular of nozzles, which differ significantly in the size of their opening (nozzle opening geometries), since due to the possible with the present invention higher flow rate of the rinsing liquid, ie jet prints, obstruction or avoided can be 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 makes it possible to clean the heat exchanger on a regular basis as required, a dryer with improved efficiency and a significantly reduced susceptibility to failure 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. Figure 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.

Figure 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.

Fig. 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 FIGS. 1 to 3, the long arrows indicate the flow direction of the process air. The dryer 1 shown in FIG. 1 has a drum, which is rotatable about a horizontal axis, as a drying chamber 3, within which drivers 25 are fastened for moving laundry items during a drum rotation. The process air is guided in the process air duct 2 by means of a blower 6 via an electric heater 4 through the drum 3. In this case, heated air from the rear, ie from the side of the drum 3 opposite the filling opening 22, is directed by the electric heater 4 through the perforated bottom into the drum 3. The heated process air thus passes into the drum 3, where in Fig. 1, not shown wet laundry items moisture is removed.

After exiting the drum 3, the process air laden with moisture in the process air duct 2 flows through a lint filter 16 within the door 22. Subsequently, the process air flow in the door 22 is deflected downwards and directed to an air-to-air heat exchanger 5. As a result of cooling, the moisture absorbed by the process air from the items of laundry condenses there and is collected in a condensate tray 7.

The condensate or aqueous liquid 33 collected in the condensate tray 7 is conveyed to the air-to-air heat exchanger via a condensate channel 23 in which there is a pump 9 driven by a BLDC (Brushless DC) motor 8 5 headed.

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

The used rinsing liquid 33 (condensate used for cleaning, possibly diluted with tap water) can, if necessary due to the contamination, be disposed of via a line not shown to the outside of the device. In order to determine a cleaning requirement, the condensation dryer 1 has a first temperature sensor 29 in front of the air-air heat exchanger 5 and a second temperature sensor 30 downstream of the air-air heat exchanger 5. In a clean air-air heat exchanger 5, the heat exchange proceeds very efficiently, so that the process air cools strongly when passing through the air-to-air heat exchanger 5. However, if the air-air heat exchanger 5 is contaminated by the deposition of lint, the efficiency of the air-to-air heat exchanger 5 decreases. In this case, the process air does not cool as much when passing through the air-to-air heat exchanger 5. As a result, in the case of a contaminated air-air heat exchanger 5, a decreased temperature difference ΔΤ between the first temperature sensor 29 and the second temperature sensor 30 is detected.

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

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

In the case of determined cleaning requirement, in the embodiment shown in FIG. 1 the air-air heat exchanger 5 is cleaned by means of the condensate 33 possibly mixed with water from the water supply line 20 as rinsing liquid. The rinsing liquid 33 thus comprises condensate which has previously accumulated in the air-air heat exchanger 5 and is pumped from the condensate tray 7 by means of the pump 9 via a condensate channel 23 into the air-air heat exchanger 5. After passing through the air-to-air heat exchanger 5, the rinsing liquid 33 is collected in the condensate tray 7 and can be pumped back to the heat exchanger 5 via the condensate channel 23. This cycle can be repeated several times until a desired cleaning is achieved. The drum 3 is mounted in the embodiment shown in Fig. 1 at the rear bottom by means of a pivot bearing and front by means of a bearing plate 35, the drum 3 rests with a brim on a sliding strip 36 on the bearing plate 35 and is held at the front end. The control of condensation dryer 1 via a control device 10, which can be controlled by the user via an operating unit 24.

In the embodiment shown in Figure 1, the fan 6 and the drum 3 are driven by a drive motor 28.

To monitor the liquid level in the condensate pan 7, a level sensor 19 is mounted in this.

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

Figure 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 Figure 1, the cooling of the warm, laden with moisture process air 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 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 passes.

In the second embodiment of a condensation dryer shown in Fig. 2, the determination of a cleaning requirement for the air-to-air heat exchanger 5 and its cleaning carried out as shown in FIG.

In the following, particular attention will be given to differences from the embodiment shown in FIG. Otherwise, the same reference numerals mean the same components that - unless otherwise stated - perform the same functions as described in Fig. 1.

In the second embodiment shown in Fig. 2, the condensate 33 is pumped with a pump not shown in the condensate channel 23 and then in a condensate tank 34, where the condensate 33 before further use can be cached. To clean the air-to-air heat exchanger 5, the condensate 33 is then pumped by means of the BLDC motor 8 driven pump 9 in the air-to-air heat exchanger 5. In this case, the number of revolutions of the BLDC motor 8 can be varied within a wide range, so that the dependent delivery capacity of the pump 9 and thus the achieved flow rate of the condensate 33 are adjusted to a determined degree of contamination of the air-to-air heat exchanger 5 can. As a result, cleaning of the air-to-air heat exchanger 5 from lint, etc. can be efficiently achieved. In the second embodiment of a condensation dryer according to the invention shown here, only condensate 33 is used for rinsing the air-air heat exchanger 5. This can be disposed of in an unacceptable level of contamination according to a dependent on the type and amount of laundry items to be dried period in a manner not shown here.

Figure 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 has. The short arrows with unfilled arrowhead indicate the flow direction of the refrigerant. Otherwise, the parts shown in Fig. 3 with the same reference numerals have the same meaning as in Figs. 1 and 2.

The moist, warm process air leaves the drum 3 via a lint filter 16 and flows in the process air duct 2 to the evaporator 15 of the heat pump, where it is cooled. In the evaporator 15, a refrigerant circulating in the heat pump circuit 12, 13, 14, 15 is vaporized and fed via a compressor 13 to a condenser 12, where the refrigerant passes back into the liquid state with release of heat to the cooled and dehumidified process air flowing in the process air duct. The present in liquid form of refrigerant is passed through a throttle valve 14 in turn to the evaporator 15, whereby the refrigerant circuit is closed. The resulting in the evaporator 15 condensate 33 is collected in a condensate pan 7 and pumped by means of a pump not shown here in a condensate channel 23, first in a condensate tank 34. From the condensate tank 34 is the cached condensate as rinsing liquid 33 by means of a pump 9, the is operated selectively via a BLDC motor 8, passed through the evaporator 15 for the purification of lint, etc. and finally reaches the condensate pan 7. From the condensate pan 7, the condensate 33 by means of the pump 9 via the condensate channel 23 back into the condensate tank 34th be pumped. This cycle can be repeated if necessary.

In the condensate tray 7 is a level sensor 19, which is designed here as a reed contact in conjunction with a permanent magnetic float. The fill level sensor 19 makes it possible for the control device 10 to determine whether sufficient condensate is present for carrying out a method according to the invention.

18 is an optical and / or acoustic display device for an indication of the presence of a predetermined minimum filling level H _min in the drain pan 7 and / or the cancel of a drying process.

Also in the third embodiment shown in FIG. 3, the fan 6 and the drum 3 are driven by the motor 30.

LIST OF REFERENCE NUMBERS

condensation dryer

Process air duct

drying chamber

heater

Air-air heat exchanger

fan

Drain pan

Electric motor; BLDC motor

pump

control device

Clock

Condenser of a heat pump

Compressor of a heat pump

throttle valve

Evaporator of a heat pump

lint

evaluation

Display device, optical and / or acoustic level sensor

Water supply line

External water supply

door

condensate channel

operating unit

laundry agitator

Cooling air inlet

Cooling fan

Drive motor for blower and drum

First temperature sensor _n

25

30 Second temperature sensor

31 Cooling air outlet

32 cooling air duct

33 Aqueous liquid, condensate

34 condensate tank, storage tank 35 bearing plate

36 sliding strips

37 counters

Claims

PATENT CLAIMS

Condensation dryer (1) with a drying chamber (3) for items of laundry to be dried, a process air duct (2) in which there is a heater (4) for heating the process air, a heat exchanger (5,15) for cooling the process air after it has passed through the drying chamber (3) and a fan (6) for transporting the process air, a control device (10), a condensate tray (7) and a pump (9) driven by an electric motor (8) for transporting air from the condensate tray (7). aqueous liquid (33), characterized in that

the electric motor (8) used to operate the pump (9) is a BLDC motor.

Condensation dryer (1) according to claim 1, characterized in that the pump (9) is arranged in a condensate channel (23) between the condensate trough (7) and a component (5, 15, 16) of the condensation dryer (1) to be cleaned.

Condensation dryer (1) according to claim 2, characterized in that the component (5, 15, 16) to be cleaned is the heat exchanger (5, 15) and / or a lint grid (16).

Condensation dryer (1) according to one of claims 1 to 3, characterized in that it has means (10,1 1, 17,37) for recognizing the need for cleaning of components (5,15, 16) to be cleaned.

Condensation dryer (1) according to claim 4, characterized in that it has a clock (1 1) as a means (10, 1 1, 17,37) for recognizing the need for cleaning, which determines a total duration t _sum of drying processes carried out so far and with a predetermined limit duration t| _in compares, and / or the condensation dryer (1) has an evaluation unit (17) as a means (10,1 1, 17,37) for recognizing the need for cleaning, which determines a total amount M of previously dried items of laundry and with a predetermined limit total amount M| _in compares.

6. Condensation dryer (1) according to claim 4, characterized in that it has a counter (37) as a means (10, 11, 17,37) for recognizing the need for cleaning, which determines the number n of drying processes that have already been carried out and with a predetermined limit number ni _compares .

7. Condensation dryer (1) according to claim 4, characterized in that the condensation dryer (1) has a first temperature sensor (29) and a second temperature sensor as a means (10, 11, 17,37) for detecting the need for cleaning in the process air duct (2). (30), which are arranged on opposite sides of the heat exchanger (5, 15) and by comparing a difference ΔΤ of the temperatures measured by them with a predetermined limit value for the temperature difference AT| allow the cleaning needs _{to be} determined.

8. Condensation dryer (1) according to one of claims 1 to 7, characterized in that it has an acoustic and / or optical display device (18) for indicating a cleaning requirement and / or for indicating the implementation of a cleaning process.

9. Condensation dryer (1) according to one of claims 1 to 8, characterized in that a fill level sensor (19) is arranged in the condensate pan (7).

10. Condensation dryer (1) according to one of claims 1 to 9, characterized in that it is connected to an external via a water supply line (20).

Water supply (21) can be connected so that an external aqueous liquid from the external water supply (21) can be mixed with the condensate (33).

1 1. Condensation dryer (1) according to one of claims 1 to 10, characterized in that in the process air duct (2) as a heat exchanger (5, 15) there is an air-air heat exchanger (5) or an evaporator (15) of a heat pump ( 12, 13, 14,15). Method for operating 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) for cooling the process air after it has passed through the drying chamber (3) and a fan (6) for conveying the process air are located, a control device (10), a condensate pan (7) and a pump (9) driven by an electric motor (8) for conveying an aqueous mixture originating from the condensate pan Liquid (33) in a condensate channel (23), the electric motor (8) used to operate the pump (9) being a BLDC motor, characterized in that

(a) a condensate is conveyed in the condensate pan (7) using the pump (9) driven by the BLDC motor to clean a component (5, 15, 16) of the condensation dryer (1), and

(b) the condensate is brought into contact with the component (5, 15, 16).

Method according to claim 12, characterized in that steps (a) and (b) are carried out before or after carrying out a drying process.

Method according to claim 12 or 13, characterized in that in a rinsing program step (a) comprises several sections (a) in which the pump (8) is switched off and/or a delivery rate of the pump (8) is different.

Method according to one of claims 12 to 14, characterized in that a washing program is carried out with regard to a determined cleaning requirement.