DE102011002469A1 - Method for operating e.g. condensation-dryer for drying laundry pieces, involves measuring temperature of air depending on time, and determining non-uniform laundry distribution if variation reaches/exceeds upper limit - Google Patents

Abstract

The method involves measuring temperature of processing air depending on time, and determining time variation by a temperature sensor (13). A non-uniform laundry distribution is determined if the time variation reaches or exceeds a preset upper limit. The temperature sensor is provided behind a drum output (21). A heater (4) for heating the processing air is provided in a processing air channel (2). Measure against non-uniform laundry distribution and/or negative effect of drying process is corrected if the time variation exceeds the preset upper limit. An independent claim is also included for a dryer comprising a drum.

Description

The invention relates to a method for operating a dryer with non-uniform distribution of laundry and a suitable for carrying out this method dryer.

In a dryer, air (so-called process air) is passed through a fan via a heater in a drum containing laundry to be dried, as a drying chamber. The hot air absorbs moisture from the laundry to be dried. In an exhaust air dryer, the moist, warm process air is directed to the outside, for example in a storage room. In a condensation dryer, on the other hand, the moist, warm process air is passed, after passing through the drum, into a heat exchanger, which is usually preceded by a lint filter. In this heat exchanger (eg air-to-air heat exchanger or heat sink of a heat pump), the moist, warm process air is cooled, so that the water contained in it condenses. The condensed water (condensate) is then usually collected in a suitable container and the cooled and dried air again fed to the heater and then the drum. The absorption of moisture from wet laundry leads to a lowering of the temperature of the process air introduced into the drum. It is known to detect the temperature at the drum outlet with a temperature sensor arranged at the drum outlet and to use it to monitor the dryer.

The laundry items used in a dryer can sometimes be very large. In addition, the laundry items can be very different in size. When drying laundry in a dryer, it can therefore come to rewinders of large laundry. In addition, small pieces of laundry may be wrapped in large pieces or wrapped in the course of a drying process. Both means a non-uniform distribution of laundry, which may 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.

Against this background, the object of the present invention was to provide a method for operating a dryer in the case of non-uniform laundry distribution. The object of the invention was also to provide a suitable dryer for this purpose.

The solution of this object is achieved according to this invention by a method having the features of the corresponding independent claim and the dryer of the corresponding independent claim. Preferred embodiments 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.

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

The invention thus relates to a method for operating a dryer with a drum for items to be dried, a process air duct, in which a heater for heating the process air, a blower for conveying the process air and a temperature sensor are located behind a drum outlet, and a control device comprising the steps:

• (A) by means of the temperature sensor, the temperature T of the process air is measured as a function of the time t and determines a time change ΔT / Δt; and
• (b) in the event that the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) ^max1 , an uneven laundry distribution is detected.

The temperature sensor is located as close as possible 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 preferably located in a bearing plate of the dryer.

• (c) 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, durchgeführt. „Negative Auswirkung auf den Trocknungsprozess” bedeutet hierbei insbesondere ein Unzugänglichmachen von Wäschestücken oder deren Teilen für die zur Trocknung verwendete warme Prozessluft.

In a preferred embodiment of the invention, a step (c),

• (c) in the case that the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) ^max1 , becomes Action taken against the uneven laundry distribution and / or corrected their negative impact on the drying process carried out. 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.

• (d) erneute Messung der Temperatur T der Prozessluft in Abhängigkeit von der Zeit t und Bestimmung von deren zeitlicher Änderung ΔT/Δt; und
• (e) für den Fall, dass die zeitliche Änderung ΔT/Δt nicht eine vorgegebene untere Grenze (ΔT/Δt)^min erreicht oder unterschreitet, wird erneut eine Maßnahme gegen die ungleichmäßige Wäscheverteilung ergriffen und/oder die Korrektur der negativen Auswirkung auf den Trocknungsprozess beibehalten oder modifiziert,

durchgeführt.In this case, the steps are preferably after the implementation of the measure of step (c)

• (d) remeasuring the temperature T of the process air as a function of the time t and determining its time change ΔT / Δt; and
• (e) in the event that the time change ΔT / Δt does not reach or fall below a predetermined lower limit (ΔT / Δt) ^min , a measure against the uneven laundry distribution is taken again and / or the correction of the negative effect on the drying process is maintained or modified,

carried out.

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. Thus, for example, the drum can be operated with a reversing operation for a certain period of time in both directions of rotation.

After a nonuniform laundry distribution has been determined, the drying process is preferably modified for a prolonged drying time. In this way, it can be taken into account that 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 a drying process is carried out for a longer period of time for an equally high degree of drying of the item got to.

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 period t for a drying process, a power of the heater and / or a power of the blower be changed such that the energy consumption is substantially equal to, and preferably not equal to, a power consumption prior to detecting the uneven laundry distribution is larger.

In the method ^{according to} the invention, (ΔT / Δt) ^{max1 is} preferably at least 0.2 ° C per second, more preferably at least 0.5 ° C per second, and most preferably at least 0.7 ° C per second.

Preferably, a detected uneven laundry distribution is displayed on a 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 thereto, colored lights, z. B. LEDs, which in turn shine in particular orange or red, are used.

In a preferred embodiment of the invention, (ΔT / Δt) ^{max1 is set} with respect to a relationship between load and limit value (ΔT / Δt) ^max1 stored in the control ^device . In this case, loading of the drum with items of laundry is preferably determined in a manner known per se prior to carrying out steps (a) and (b).

• (f) für den Fall, dass die zeitliche Änderung ΔT/Δt eine vorgegebene obere Grenze (ΔT/Δt)^max2 > (ΔT/Δt)^max1 erreicht oder überschreitet, wird die Heizung abgeschaltet und/oder auf einer Anzeigevorrichtung eine ungleichmäßige Wäscheverteilung festgestellt, gegen die eine automatische Maßnahme nicht ergriffen und/oder deren negative Auswirkung auf den Trocknungsprozess nicht automatisch korrigiert werden kann.

In a particularly preferred embodiment of the method according to the invention, which primarily serves to ensure the safety of the operation of the dryer, a step (f) is carried out:

• (f) in the event that the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) ^max2 > (ΔT / Δt) ^max1 , the heating is switched off and / or a non-uniform distribution of laundry is detected on a display device, against which an automatic measure can not be taken and / or whose negative impact on the drying process can not be automatically corrected.

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

eingerichtet ist.The invention also relates to a dryer with a drum for items to be dried, a process air duct in which a heater for heating the process air, a blower for conveying the process air and a temperature sensor are behind a drum outlet, and a control device, wherein the control device to carry out a method comprising the steps

• (A) by means of the temperature sensor, the temperature T of the process air is measured as a function of the time t and determines a time change ΔT / Δt; and
• (b) in the event that the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) ^max1 , an uneven laundry distribution is detected,

is set up.

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, in the case of a dryer, a drying process can also be carried out optimally if there is the risk of rewinders due to the presence of very large items of laundry or the presence of items of laundry of very different sizes. The The inventive method can avoid or eliminate laundry Aufwickler. 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.

Features of the advantageous developments of the invention according to the subclaims can be applied in any combination and on their own within the scope of the invention. Preferred features of the method are analogously applicable as preferred features of the dryer. Further details of the invention will become apparent from the following description of a non-limiting embodiment of a dryer according to the invention, in which a method according to the invention can be carried out for its operation. Reference is made to the figure.

The figure 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 shown 1 has a drum rotatable about a horizontal axis 3 for the absorption of laundry items, not shown here, ie, as a drying chamber, on, within which carriers 5 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 air-to-air heat exchanger 17 and an electric heater 4 through the drum 3 guided. It is by the electric heater 4 heated air from behind, ie from a door 15 opposite side of the drum 3 through whose perforated bottom into the drum 3 directed.

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

The drum 3 is in the embodiment shown in the figure at the rear bottom by means of a pivot bearing and front by means of a bearing plate 7 stored, with the drum 3 with a brim on a sliding strip 8th on the bearing plate 7 rests and is held at the front end. The control of the dryer via a control device 10 by the user via a control unit 9 can be regulated. A temperature sensor 13 is with the control device 10 connected.

In the embodiment shown in the figure, the blower 6 and the drum 3 through the engine 16 driven.

In carrying out the method according to the invention by means of the temperature sensor 13 the temperature T of the process air is measured as a function of the time t and a time change .DELTA.T / .DELTA.t determined, and in the event that the time change ^.DELTA.T / .DELTA.t reaches or exceeds a predetermined upper limit (.DELTA.T / .DELTA.t) ^max1 , a nonuniform laundry distribution detected. For this purpose, the control device 10 and an evaluation unit included in it 12 used.

In the event that the time change .DELTA.T / .DELTA.t reaches or exceeds a predetermined upper limit (.DELTA.T / .DELTA.t) ^max1 , here 1 ° C / sec, a measure against the uneven laundry distribution is taken and corrected their negative impact on the drying process.

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

After carrying out these measures, a new measurement of the temperature T of the process air as a function of the time t and a renewed determination of the change in time .DELTA.T / .DELTA.t takes place. In the event that the time change ΔT / Δt does not reach or fall below a predetermined lower limit (ΔT / Δt) ^min , a measure against the uneven laundry distribution is taken again and / or the correction of the negative effect on the drying process is maintained or modified.

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 heating 4 is lowered and a performance of the blower 6 increased. In this case, a period of time t _dry for a drying process, the power of the heater 4 and the performance of the blower 6 changed so that the energy consumption is substantially equal to a prior to determining the uneven laundry distribution energy consumption.

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

In carrying out the method is initially using a common method, eg. B. a determination of the weight gain of the drum 3 , a load of the drum 3 intended with laundry. Subsequently, (ΔT / Δt) ^max1 with respect to one in the control ^device 10 deposited relationship between load and limit (.DELTA.T / .DELTA.t) ^max1 set.

In the event that the time change ^.DELTA.T / .DELTA.t reaches or exceeds a predetermined upper limit (.DELTA.T / .DELTA.t) ^max2 > ( ^.DELTA.T / .DELTA.t) ^max1 , the heating 4 switched off and on the display device 11 detected a non-uniform distribution of laundry, against which an automatic action can not be taken and / or its negative impact on the drying process can not be corrected automatically.

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 device

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 exit

Claims (14)

Method for operating a dryer ( 1 ) with a drum ( 3 ) for laundry items to be dried, a process air duct ( 2 ), in which a heating ( 4 ) for heating the process air, a blower ( 6 ) for the transport of process air and a temperature sensor ( 13 ) behind a drum exit ( 21 ) and a control device ( 10 ), comprising the steps: (a) by means of the temperature sensor ( 13 ) the temperature T of the process air is measured as a function of time t and a time change ΔT / Δt determined; and (b) in the event that the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) ^max1 , an uneven laundry distribution is detected. A method according to claim 1, characterized in that the step (c), (c) in the event that the time change ^.DELTA.T / .DELTA.t reaches or exceeds a predetermined upper limit (.DELTA.T / .DELTA.t) ^max1 , becomes a measure against the uneven laundry distribution taken and / or whose negative impact on the drying process is corrected. A method according to claim 2, characterized in that after the implementation of the measure of step (c), the steps (d) remeasurement of the temperature T of the process air as a function of the time t and determination of their temporal change .DELTA.T / .DELTA.t; and (e) in the event that the time change ΔT / Δt does not reach or fall below a predetermined lower limit (ΔT / Δt) ^min , a measure against the non-uniform laundry distribution is taken again and / or the correction of the negative effect on the drying process maintained or modified. A method according to claim 2 or 3, characterized in that the measure against the uneven distribution of laundry is that a rotation of the drum ( 3 ) in terms of direction and number of rotations per minute and / or duration of rest and rotation times is changed in order to minimize the uneven laundry distribution. Method according to one of claims 1 to 4, characterized in that the drying process is modified after a detected uneven laundry distribution with respect to a prolonged drying time. Method according to claim 5, characterized in that a power of the heating ( 4 ) and / or a performance of the blower ( 6 ) is raised. Method according to one of claims 1 to 6, characterized in that a time duration t _dry for a drying process, a performance of Heater ( 4 ) and / or a power of the blower ( 6 ) are changed so that the energy consumption is substantially equal to an energy consumption provided before the uneven laundry distribution is detected. Method according to one of claims 1 to 7, characterized in that (ΔT / Δt) ^max1 ≥ 0.2 ° C per second. Method according to one of claims 1 to 8, characterized in that a detected uneven laundry distribution on a display device ( 11 ) is shown. Method according to one of claims 1 to 9, characterized in that (ΔT / Δt) ^max1 with regard to a in the control ^device ( 10 ) stored relationship between load and limit (.DELTA.T / .DELTA.t) ^{max1 is} set. Method according to one of claims 1 to 10, characterized in that before carrying out steps (a) and (b) a loading of the drum ( 3 ) is determined with laundry. A dryer with a drum for laundry to be dried, a process air duct in which a heater for heating the process air, a blower for conveying the process air and a temperature sensor are located behind a drum outlet, and a control device, wherein the control device for performing a method comprising the steps (A) by means of the temperature sensor, the temperature T of the process air is measured as a function of the time t and determines a time change ΔT / Δt; and (b) in the event that the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) max1, an uneven laundry distribution is detected, is set up. Method according to one of Claims 1 to 11, characterized in that a step (f) is carried out: (f) in the event that the time change ΔT / Δt exceeds a predetermined upper limit (ΔT / Δt) ^max2 > (ΔT / Δt ) ^max1 reaches or exceeds the heating ( 4 ) and / or on a display device ( 11 ) has detected an uneven distribution of laundry against which an automatic measure can not be taken and / or its negative impact on the drying process can not be automatically corrected. Dryer ( 1 ) with a drum ( 3 ) for laundry items to be dried, a process air duct ( 2 ), in which a heating ( 4 ) for heating the process air, a blower ( 6 ) for the transport of process air and a temperature sensor ( 13 ) behind a drum exit ( 21 ) and a control device ( 10 ), characterized in that the control device ( 10 ) for carrying out a method comprising the steps: (a) by means of the temperature sensor ( 13 ) the temperature T of the process air is measured as a function of time t and a time change ΔT / Δt determined; and (b) in the event that the time change ΔT / Δt reaches or exceeds a predetermined upper limit (ΔT / Δt) ^max1 , an uneven laundry distribution is detected.

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