EP2527517A1 - Dryer with RFID reader unit and method for its operation - Google Patents

Abstract

The dryer (1) has a drum (3) for laundry items (22) to be dried, controller and a process air channel, in which a heater and fan are located. The heater is provided for heating the process air, where the fan is provided for conveying the process air. A Radio-frequency identificationreader unit (24,25,26) is provided for reading the information from a radio-frequency identification transponder (23). The radio-frequency identification transponder is placed in the drum. An independent claim is included for a method for operating a dryer.

Description

The invention relates to a dryer with a drum as a drying chamber for laundry to be dried, a controller and a process air duct in which there is a heater for heating the process air and a fan for the transport of the process air. In particular, the invention relates to such a dryer, in which the tracking of the position of laundry items in the drum is possible. The invention also relates to a preferred method of operating this dryer.

In a dryer, air (so-called process air) with the help of a fan via a heater in a drying laundry containing drum is passed as a drying chamber. The hot air absorbs moisture from the items to be dried, in a vented dryer the moist warm process air is passed to the outside after passage through the drum, for example in a room, and in a condensation dryer in a heat exchanger (eg air-air heat exchanger or heat sink a heat pump), where the moist, warm process air is cooled, so that the water contained in it condenses.

The items of laundry used in a dryer can differ very clearly in their size. When drying laundry items in a dryer, it can therefore come to rewinders (hereinafter also referred to as "rolling up") of large laundry items. In addition, small pieces of laundry may be wrapped in large pieces or wrapped in the course of a drying process. Both circumstances cause a non-uniform distribution of laundry, which can have an unfavorable influence on the course of a drying process in the dryer. Thus, the degree of drying, the time required for drying and the energy required for drying can be adversely affected. In addition, it can lead to an irregular drying result and creasing in the laundry. Finally, a user of the dryer often has great difficulty to separate the rolled-up and rolled-up laundry. The tracking of a rewinding operation and thus the investigation with regard to remedial measures can so far only be carried out after a drying test. A live monitoring of the location of Laundry items are only possible by means of a camera through observation through a drum opening. As a result, however, only laundry in the front part of the drum can be observed.

The DE 10 2008 036 943 A1 describes a washing machine for cleaning or treating textiles, comprising a control unit and a detection device, which can determine information about the laundry supplied to the washing machine or the detergent supplied to the washing machine and transmitted to the control unit, the control unit determines an appropriate washing program based on the information transmitted , The detection device may be, for example, an RFID reader.

The DE 10 2009 023 228 A1 describes a device for detecting certain environmental influences of a garment or a bandage, wherein the device comprises a data processing unit and a nonvolatile memory and the data processing unit receives and evaluates the signals of at least one temperature sensor and a Leitwertsensors, wherein in the memory at least one value is stored, the maximum life, the remaining life of the garment or bandage and / or the still allowed washing and / or drying operations corresponds. On the basis of the determined temperature and the determined conductance, the data processing unit determines the currently remaining service life and / or the number of washing and / or drying operations that have taken place. The device preferably exchanges data with a read-out device and / or a washing machine or a drying device or a transponder located in the region of a washing machine or the drying device by means of RFID technology.

The DE 197 47 150 A1 describes a method for washing and / or drying textile products by household appliances. The textile products are provided with at least one machine-readable transponder with at least one electronic circuit containing information about the textile product, and the household appliances are equipped with at least one device for reading the information about the textile product. The method comprises the steps of reading the information from the at least one transponder of the textile products to be treated by means of the at least one read-out device into a household appliance and determining the other Treatment of textile products according to the information read by the household appliance.

The DE 10 2008 041 394 A1 describes a contactless readable identification mark, preferably an inductively or by radio readable RFID mark, and a domestic appliance, in particular a cooking appliance, with a read-out unit for reading data about a product, in particular a food product. The home appliance can also be a washing machine, dryer, etc. The home appliance is set up to control the treatment process on the basis of a read coded product information. The treatment information may include, for example, process parameters for laundry, wherein the information may be present on the laundry or separately therefrom, eg in a list.

The DE 10 2008 005 363 A1 describes a washing machine with a device for the portioned addition of detergent active ingredients and with an electronic program control and with devices for inputting and / or determining information about the desired or required composition of a treatment program and for determining and / or entering laundry-related parameters, namely of Art , Pollution and / or mass of the introduced into the washing machine laundry, as well as with a reading device for automatically reading in information regarding the detergent active ingredients as well as the laundry.

The DE 10 2006 049 862 A1 describes a device for providing information about the location of an object provided with a passive transponder, the location being in a reception area of at least three antennas arranged at different antenna positions, in particular a device and a method for determining the position of a passive transponder in an RFID system. Since RFID technology has not been able to localize objects with respect to their position in a local resolution, ie with an accuracy of, for example, a few millimeters, the position, direction and / or movement of a passive transponder are now determined by defining a measurement area by a plurality of reader antennas. in whose reception area the passive transponder or an object to which the passive transponder is attached is located. Specific application examples are robotic applications where objects are located by a robot and then grasped.

The DE 10 2010 000 432 A1 describes a method for operating a laundry treatment device with a rotatable drum, wherein the material to be treated is imaged in the treatment chamber and based on its recording image, a state of movement of the material to be treated is determined. The laundry treating appliance, in particular a tumble dryer, is controlled on the basis of the determined state of motion. Exemplary imaging devices may be optical sensors that can capture still or moving images, such as a camera that can record visible and / or invisible images. There may be multiple imaging devices that receive the same or different areas of the treatment chamber.

The US 2009/0217711 A1 describes a sensor device and a method for determining a local position and a washing machine. The sensor device may be adapted for use in a washing machine for determining a position of a rotatably mounted drum. In particular, RFID transponders can also be used.

Against this background, it was an object of the present invention to provide a dryer and a method for operating this dryer, with the help of which the problems of the rolling up of laundry items and / or of uneven laundry falling behavior, i. a non-uniform distribution of laundry in the drum, observed and can be reduced as possible.

The solution of this object is achieved according to this invention by a dryer and a method for its operation with the features of the corresponding independent claims. Preferred embodiments of the dryer according to the invention and of the method according to the invention are listed in the respective 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 dryer with a drum for laundry to be dried, a controller, a process air duct in which there is a heater for heating the process air and a fan for the transport of the process air, the dryer at least three RFID reading units for the Having read information from at least one located in the drum RFID transponder.

In general, the dryer and in particular its at least three RFID reading units and the controller are set up so that information can be read from the RFID transponder when the at least one RFID transponder is mounted in the drum on one or more of the laundry items and / or is available separately.

With the arranged in the dryer RFID reader RFID transponder and thus the information stored on this information can be read wirelessly and without contact. The reading unit can emit, for example, an electromagnetic signal with which an electrical circuit in an RFID transponder is excited. This can be done, for example, that certain information bits are represented on the RFID transponder by a resonant circuit of an associated unique frequency. The excitation can then be done, for example broadband over the frequencies of the resonant circuits or by scanning the frequency band. The signals emitted by the RFID transponder are then received by the at least three reading units and forwarded to the controller of the dryer for evaluation with regard to the information contained on the RFID transponder. The detection of the information with the reader generally takes place regularly at certain intervals, which usually depend on the type of information to be read.

The controller can use the information transmitted by the at least one RFID transponder, ie data, to display product or position information and / or to initiate corresponding program steps, eg in a drying program.

The information contained on the RFID transponders is not limited and may in addition to generally information on the location and movement of the RFID transponder (the latter hereinafter in terms of their time dependence referred to as "movement"), especially when attached to garments RFID transponders also Information about the type of garment included, such as dimensions, weight, type of fabric (cotton, wool, silk, etc.), color and, where appropriate, manufacturer information on a treatment program.

In general, the control of the dryer is set up in order to determine the location and / or the course of movement of the at least one RFID transponder in the drum based on the information received from the at least three RFID reading units.

The dryer of the present invention is also preferably capable of autonomous detection or acquisition of wash related data so that in embodiments of the invention, a user no longer needs to promptly enter the appropriate information about laundry items to the dryer, such as via a drying program selector switch.

In a preferred embodiment of the dryer, if the relative movement between the drum and the at least one RFID transponder in a laundry item and / or between the drum and the separate transponder is too small, the controller determines that the laundry items are being rolled up. In this case, a critical lower limit for the relative movement of the RFID transponder can be stored in the control, upon reaching or falling below the controller determines after the evaluation of the information on the relative movement a rolling up of the laundry items. Then, for example, countermeasures can be automatically taken or suggested to a user of the dryer via the display device.

In a further preferred embodiment of the dryer, the controller determines at a deviation of a movement sequence of a predetermined periodicity on an unfavorable case of the laundry items. The predetermined periodicity will in this case generally depend on a movement program of the drum. The frequency of the drum rotation should preferably also have a corresponding frequency and thus Periodicity of the laundry case correspond. If this is not the case, this circumstance may be an indication of an unfavorable case of the laundry items due to uneven laundry distribution in the drum, for example by rolling up laundry.

Preferably, the dryer has a display device for rolling up and / or an unfavorable case of the laundry items, which situations may also be generally represented by the detection of uneven laundry distribution in the display device. This may be an optical or acoustic display device. In an optical display device can be pointed to the uneven distribution of laundry by displaying a corresponding text. Alternatively or in addition to this, colored lights, e.g. LEDs, which in turn shine in particular orange or red, are used.

In general, the dryer can select or calculate a drying program adapted to the introduced laundry items (or their distribution in the drum) on the basis of the data read from the RFID transponder. The necessary parameters for its implementation, for example, drying time, drying temperature and movement program of the drum can then be set automatically or displayed to a user of the dryer as recommendations by means of the display device.

So that the RFID reading units can determine the position of the at least one RFID transponder in the drum as accurately as possible, three RFID reading units are generally not arranged on a straight line. Incidentally, there is great freedom of design with regard to the arrangement of the RFID reading units. In order to easily carry out any necessary connections, it may be expedient to place the RFID reading units stationary in the dryer. In the context of the invention, however, it is also possible and can also be useful to ensure high signal strengths for communication with the RFID transponders to arrange one or more of the RFID reader units in the laundry drum, where they rotate with them. Connections for power supply and communication are then expediently wirelessly, for example via radio frequency interfaces executed.

In a particularly preferred embodiment of the dryer according to the invention, there is a first RFID reading unit above the drum, a second RFID reading unit in front of or behind the drum and a third RFID reading unit laterally from the drum.

In the dryer according to the invention may be used as a supplementary measure preferably also a tracking of the temperature to determine a non-uniform distribution of laundry items in the drum.

In a further preferred embodiment of the dryer, therefore, a temperature sensor is located behind a drum outlet of the dryer. If present, the temperature sensor is preferably as close to the drum outlet and in the presence of a heat exchanger in the process air duct in any case before the heat exchanger. The temperature sensor is very particularly preferably in a bearing plate of the dryer.

1. (a) Einbringen mindestens eines RFID-Transponders in die Trommel;
2. (b) Einbringen mindestens eines Wäschestücks in die Trommel, wobei mindestens ein RFID-Transponder auf einem Wäschestück angebracht sein kann;
3. (c) Drehen der Trommel;
4. (d) Auslesen der Informationen aus dem mindestens einen in der Trommel befindlichen RFID-Transponder; und
5. (e) Bestimmen von Ort und/oder Bewegungsablauf des mindestens einen RFID-Transponders in der Trommel durch Auswerten der von den mindestens drei RFID-Leseeinheiten empfangenen Informationen in der der Steuerung.

The invention also relates to a method for operating a dryer with a drum for items to be dried, a controller, a process air duct in which a heater for heating the process air and a blower for the transport of the process air, wherein the dryer at least three RFID Reading units for reading information from at least one in-drum RFID transponder, comprising the steps

1. (A) introducing at least one RFID transponder into the drum;
2. (B) introducing at least one item of laundry into the drum, wherein at least one RFID transponder can be mounted on a piece of laundry;
3. (c) rotating the drum;
4. (d) reading the information from the at least one RFID transponder located in the drum; and
5. (E) determining the location and / or movement sequence of the at least one RFID transponder in the drum by evaluating the information received from the at least three RFID reader units in the controller.

The determination under point (e) is generally equated with a determination of the location and / or movement sequence of the laundry items located in the drum.

Since the process according to the invention is preferably a drying process, heated process air is generally also conducted into the drum by means of the heating. This takes place in particular in step (c).

In a preferred embodiment of this method, if the relative movement between the drum and the at least one RFID transponder in a piece of laundry and / or a separate transponder is too small, the controller determines a rolling up of the items of laundry.

Likewise, it is preferred in this method that the controller determines a disadvantageous case of the laundry items in the event of a deviation of a movement sequence from a predetermined periodicity.

Moreover, a determination of the rolling up and / or the unfavorable case of the laundry items is advantageously displayed on a display device.

In a preferred embodiment, after a determination of the reeling and / or the unfavorable case of the laundry items, generally a nonuniform laundry distribution, a measure against an uneven laundry distribution is taken and / or the negative effect on the drying process is corrected.

In this case, "negative effect on the drying process" means, in particular, making laundry items or their parts inaccessible to the warm process air used for drying.

The measure against the uneven laundry distribution is preferably that a rotation of the drum with respect to direction and rotation number per minute and / or duration of rest and rotation times is changed in order to minimize the uneven laundry distribution. For example, the drum with a Reversing operation for a certain period in both directions.

After a nonuniform laundry distribution has been determined, the drying process is preferably modified for a prolonged drying time. Preferably, a predetermined time for a drying process is extended after a determined rolling up and / or unfavorable fall of the laundry items. In this way, it can be taken into account that a smaller piece of laundry wrapped in a larger item of laundry or an inner portion of a larger wound item of laundry is less accessible to the warm process air used for drying and thus carries out a drying process for a longer period of time for an equally high degree of drying of the item must become. Moreover, in the method according to the invention, advantageously, a power of the heater is reduced and / or an output of the fan is increased.

Moreover, in the method according to the invention, it is preferable that a time duration t _dry for a drying process, a power of the heater and / or a power of the fan be changed such that the energy consumption is substantially equal to, and preferably equal to, a power consumption prior to detecting the uneven laundry distribution is not bigger.

• (f) mittels des Temperatursensors wird die Temperatur T der Prozessluft in Abhängigkeit von der Zeit t gemessen und eine zeitliche Änderung ΔT/Δt bestimmt; und
• (g) für den Fall, dass die zeitliche Änderung ΔT/Δt eine vorgegebene obere Grenze (ΔT/Δt)^max1 erreicht oder überschreitet, wird eine ungleichmäßige Wäscheverteilung festgestellt.

In a further preferred embodiment of the method according to the invention, in which a temperature sensor is located behind a drum outlet of the dryer, the following steps are additionally carried out:

• (f) the temperature T of the process air is measured as a function of the time t by means of the temperature sensor and a time change ΔT / Δt determined; and
• (g) in the case where the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) ^max1 , uneven distribution of the laundry is detected.

• (h) für den Fall, dass die zeitliche Änderung ΔT/Δt eine vorgegebene obere Grenze (ΔT/Δt)^max1 erreicht oder überschreitet, wird eine Maßnahme gegen die ungleichmäßige Wäscheverteilung ergriffen und/oder deren negative Auswirkung auf den Trocknungsprozess korrigiert.

In addition, advantageously, a step (h) can be carried out:

• (h) in the event that the time change ^.DELTA.T / .DELTA.t reaches or exceeds a predetermined upper limit (.DELTA.T / .DELTA.t) ^max1 , a measure against the uneven laundry distribution is taken and / or its negative effect on the drying process is corrected.

In a preferred embodiment of the invention, the measures against the uneven laundry distribution take into account the loading of the drum with laundry. This can be done, for example, by having certain actions adapted to it in the controller for certain loads, such as e.g. a certain movement program of the drum, determination of drying temperature and fan setting, are provided. In this case, prior to carrying out the method according to the invention, a loading of the drum with items of laundry can be ascertained in a manner known per se.

The dryer according to the invention can be designed as a pure dryer, but also as a washer-dryer. A washer-dryer is here understood to mean a combination appliance which has a washing function for washing laundry and a drying function for drying wet laundry.

The invention has the advantage that location and movement of laundry items in a drum can be determined and tracked in a simple and accurate manner. In particular, a non-uniform distribution of laundry and a rolling up and rolling up of laundry items can be easily followed. Thus, in a dryer, a drying process can be performed optimally even if there is a risk of rewinders due to the presence of very large items of laundry or the presence of laundry with very different sizes. In embodiments, the method according to the invention can avoid or eliminate laundry winders. If this is not completely possible, the drying process can at least be controlled with the method according to the invention in such a way that a drying result at least comparable with regard to the degree of drying and energy consumption is achieved.

Further details of the invention will become apparent from the following description of non-limiting embodiments of a dryer according to the invention, in which a method according to the invention can be carried out for its operation. It is on the FIGS. 1 to 3 of the accompanying drawings. The RFID transponders mentioned below not only store data for a position determination but also data on the items of laundry used (material, weight, dimensions). Accordingly, the RFID readers used are able to read not only data for a position determination.

FIG. 1 shows a first embodiment of a dryer according to the invention in a perspective view.

FIG. 2 shows a vertical section through a dryer, which is designed as a condensation dryer.

FIG. 3 shows an elongated laundry, to which a total of five RFID transponders are attached.

FIG. 1 shows a first embodiment of a dryer according to the invention in a perspective view. The dryer 1 has a drum 3 for receiving laundry items 22 to be dried. In the embodiment shown here, a first RFID transponder 23 is attached to the laundry 22 and a second RFID transponder 27 is located separately in the drum. Since the second RFID transponder 27 is moved together with the laundry items 22 in the drum 3, it makes their movements in a similar manner as the first RFID transponder 23 attached to the laundry article 22. The laundry articles 22 can be fed into the drum via a drum access 21 3 are given. Data from the RFID transponders 23 and 27 can be read out by means of the three RFID readers 24, 25 and 26. This includes a first RFID device 24 above the drum 3, a second RFID device 25 to the left in front of the drum 3 and a third RFID device 26 laterally to the right of the drum 3.

The FIG. 2 shows a vertical section through a dryer, which is designed as a condensation dryer, wherein the arrows indicate the flow direction of the process air. Other embodiments are conceivable.

The dryer 1 shown has a rotatable about a horizontal axis drum 3 for receiving to be dried, not shown here, laundry, within which drivers are fastened 5 for moving laundry during a drum rotation. The process air is guided in the process air duct 2 by means of a blower 6 through an air-air heat exchanger 17 and an electric heater 4 through the drum 3. In this case, air heated by the electric heater 4 is heated from the rear, i. from the door 15 opposite side of the drum 3, passed through the perforated bottom in the drum 3.

After exiting the drum 3, the process air laden with moisture at the drum outlet 21 flows through the filling opening of the drum 3 to a lint filter 14 within a closing the filling opening 15. Subsequently, the process air flow in the door 15 is deflected down into the process air duct 2 and the Air-to-air heat exchanger 17 passed, can be transported by the cooling air in a cooling air duct 18 by means of a cooling air blower 19. In the air-air heat exchanger 17 condenses due to cooling, a more or less large part of the process air from the laundry absorbed moisture and is collected in a condensate pan 20.

The drum 3 is at the in Fig. 2 shown embodiment at the rear bottom by means of a pivot bearing and front mounted by means of a bearing plate 7, wherein the front end is held. The control of the dryer via a controller 10, which can be controlled by the user via an operating unit 9. A temperature sensor 13 present in this embodiment is connected to the control device 10.

When in the FIG. 2 In the embodiment shown, the fan 6 and the drum 3 are driven by the motor 16.

Data from in FIG. 2 not shown RFID transponders in the drum 3 are read out by means of the visible here RFID readers 24 and 25. A third RFID reader is located - in FIG. 2 not visible - on the right here by the drum 3 hidden, when viewed in the direction of the drum access 21 right side of the drum.

When carrying out the method according to the invention, the RFID transponders, not shown here, are read out by the RFID readers and the information obtained is supplied to the controller 10 for further evaluation and possible initiation of countermeasures against uneven distribution of the laundry.

The dryer of the Fig. 2 In addition, the embodiment shown enables determination of a non-uniform distribution of the laundry based on the measured temperature of the process air. For this purpose, the temperature T of the process air is measured as a function of the time t by means of the temperature sensor 13 and a time change .DELTA.T / .DELTA.t determined, and for the case that the time change .DELTA.T / .DELTA.t reaches a predetermined upper limit (.DELTA.T / .DELTA.t) ^max1 or exceeds, an uneven laundry distribution determined. For this purpose, the controller 10 and an evaluation unit 12 contained in it are used.

In the event that the time change ^.DELTA.T / .DELTA.t reaches or exceeds a predetermined upper limit (.DELTA.T / .DELTA.t) ^max1 , a measure against the uneven laundry distribution is taken and corrected their negative impact on the drying process.

As a measure against the uneven distribution of the laundry, a rotation of the drum 3 with respect to direction and number of revolutions per minute and / or duration of rest and rotation times are changed in order to minimize the uneven distribution of the laundry. In particular, the drum 3 is operated with a reversing rhythm.

In the method according to the invention of the embodiment described here, the drying process, which was previously predetermined automatically or by a user of the dryer, is modified after a detected uneven laundry distribution with respect to an extended drying time. A power of the heater 4 is lowered and increased a power of the blower 6. At this time, a time duration t _dry for a drying process, the power of the heater 4, and the power of the blower 6 are changed so that the power consumption is substantially equal to an energy consumption provided before the uneven laundry distribution is detected.

In the dryer shown in the figure, a detected uneven laundry distribution is displayed on a display device 11, which is designed here as an LED display.

In carrying out the method, it is first carried out by a common method, e.g. a determination of the increase in weight of the drum 3, a loading of the drum 3 determined with laundry, so that the controller 10 can take into account the loading of the drum 3 in carrying out the method according to the invention.

FIG. 3 shows an elongated garment 22, to which a total of five RFID transponders, namely in the middle of an RFID transponder 23 and in the four corners a total of four RFID transponders 23 ', 23 ", 23'" and 23 "" are attached. The evaluation of the signals from these RFID transponders makes it possible, via a comparison of the relative movement of these RFID transponders to one another and to the drum, to estimate an uneven distribution of the laundry items in a drum which hampers a drying process.

LIST OF REFERENCE NUMBERS

1

dryer

2

Process air duct

3

Drum; drying chamber

4

(Electric heating

5

takeaway

6

fan

7

end shield

8th

lubricating strip

9

operating unit

10

control

11

display device

12

evaluation

13

temperature sensor

14

lint

15

door

16

engine

17

Heat exchanger; Air-air heat exchanger

18

Cooling air duct

19

Cooling fan

20

Drain pan

21

drum access

22

Laundry item (s)

23,23 ', 23 ", 23"', 23 ""

RFID transponder on a laundry

24

first RFID reader

25

second RFID reader

26

third RFID reader

27

separate RFID transponder

Claims (15)

Dryer (1) with a drum (3) for items to be dried (22), a controller (10), a process air duct (2) in which a heater (4) for heating the process air and a fan (6) for the Transport of the process air, characterized in that the dryer at least three RFID reading units (24,25,26) for reading information from at least one in-drum RFID transponder (23,23 ', 23 ", 23"' , 23 "", 27). Dryer (1) according to claim 1, characterized in that the at least one RFID transponder (23, 23 ', 23 ", 23"', 23 "", 27) in the drum (3) on one or more of the laundry items ( 22) is attached and / or present separately. Dryer (1) according to claim 2, characterized in that the controller (10) is arranged to use the information received from the at least three RFID reading units (24,25,26) the location and / or the movement of the at least one RFID Transponders (23,23 ', 23 ", 23"', 23 "", 27) in the drum (3) to determine. Dryer (1) according to claim 3, characterized in that the controller (10) at too low a relative movement between the drum (3) and the at least one RFID transponder (23,23 ', 23 ", 23"', 23 "") in a laundry item (22) and / or between the drum (3) and the separate transponder (27) determines a rolling up of the laundry items (22). Dryer (1) according to claim 3 or 4, characterized in that the controller (10) detects an unfavorable case of the laundry items (22) in the event of a deviation of a movement sequence from a predetermined periodicity. Dryer (1) according to claim 4 or 5, characterized in that the dryer (1) has a display device (11) for rolling up and / or an unfavorable case of the laundry items (22). Dryer (1) according to one of claims 1 to 6, characterized in that three RFID reading units (25,26,27) are not located in a common plane. Dryer according to claim 7, characterized in that a first RFID reading unit (24) above the drum (3), a second RFID reading unit (25) in front of or behind the drum (3) and a third RFID reading unit (26) located laterally from the drum (3). Method for operating a dryer (1) with a drum (3) for laundry items (22) to be dried, a controller (10), a process air channel (2) in which a heater (4) for heating the process air and a blower ( 6) for the transport of the process air, the dryer (1) having at least three RFID reading units (24, 25, 26) for reading out information from at least one RFID transponder (23, 23 ', 23 ") located in the drum. , 23 "', 23"", 27), comprising the steps (A) introducing at least one RFID transponder (23, 23 ', 23 ", 23"', 23 "", 27) into the drum (3); (b) introducing at least one item of laundry (22) into the drum (3), wherein at least one RFID transponder (23, 23 ', 23 ", 23"', 23 "", 27) is mounted on a garment (22) can; (c) rotating the drum (3); (d) reading the information from the at least one in the drum (3) located RFID transponder (23,23 ', 23 ", 23"', 23 "", 27); and (e) determining the location and / or movement sequence of the at least one RFID transponder (23, 23 ', 23 ", 23"', 23 "", 27) in the drum (3) by evaluating the at least three RFID transponders Reading units (24,25,26) received information in the controller (10). A method according to claim 9, characterized in that the controller (10) at too low a relative movement between the drum (3) and the at least one RFID transponder (23,23 ', 23 ", 23"', 23 "") in a piece of laundry (22) and / or a separate transponder (27) determines a rolling up of the laundry items (22). A method according to claim 9 or 10, characterized in that the controller (10) detects an unfavorable case of the laundry items (22) in the event of a deviation of a movement sequence from a predetermined periodicity. A method according to claim 10 or 11, characterized in that a determination of the reeling and / or the unfavorable case of the laundry items (22) is displayed on a display device (11). Method according to one of claims 10 to 12, characterized in that upon detection of the reeling and / or the unfavorable case of the laundry items (22), a measure against an uneven laundry distribution is taken and / or the negative effect on the drying process is corrected. A method according to claim 13, characterized in that the measure against the uneven distribution of laundry is that a rotation of the drum (3) is changed in direction and number of revolutions per minute and / or duration of rest and rotation times in order to minimize the uneven distribution of the laundry , Method according to one of claims 10 to 14, characterized in that a predetermined time for a drying process after a determined rolling and / or unfavorable case of the laundry items (22) is extended.

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