Method for operating a tumble dryer

Patent metadata

Field	Value
Publication number	US-9695547-B2
Application number	US-201214128878-A
Country	US
Kind code	B2
Filing date	Jun 26, 2012
Priority date	Jun 29, 2011
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

A method is provided for operating a laundry dryer having a rotatable drum for accommodating clothes to be dried and an apparatus for circulating drying air through the drum. The method comprises the steps of performing a drying cycle selected by a user, wherein the drying cycle comprises predetermined drum movements over time depending on the cycle selected, detecting values indicative of the temperature of the drying air exiting the drum, based on said detected values, determining that the clothes inside the drum are in tangling conditions and starting an untangling operation for untying the clothes inside the drum. The untangling operation comprises modification of the predetermined drum movements. The modification comprises at least one of the following: stopping the rotation of the drum, reversing the rotation of the drum, modifying the speed of rotation of the drum, at the end of the untangling operation, either resuming the predetermined drum movements associated to the drying cycle that was running before starting the untangling operation, or performing drum movements over time different from the predetermined drum movements associated to the drying cycle that was running before starting the untangling operation.

First claim

The invention claimed is:

1. A method for operating a laundry dryer having a rotatable drum for accommodating clothes to be dried and an apparatus for circulating drying air through the drum, the method comprising the steps of:
performing a drying cycle selected by a user, wherein the drying cycle comprises predetermined drum movements over time depending on the cycle selected,
detecting values indicative of the temperature of the drying air exiting the drum,
monitoring the detected values;
building a curve with the detected values of temperature over time,
filtering the curve with a high-pass numeric filter that cuts out all frequencies lower than a maximum frequency value indicative of an expected frequency range of a base temperature signal of drying air exiting the drum without clothes tangling conditions,
responsive to an anomaly of the detected values with respect to at least one reference parameter including the maximum expected frequency value, determining that the clothes inside the drum are in tangling conditions, and
starting an untangling operation for untangling the clothes inside the drum,
wherein the untangling operation comprises a modification of the predetermined drum movements and the modification comprises at least one of the following:
stopping the rotation of the drum, reversing the rotation of the drum, and modifying the speed of rotation of the drum, and
at the end of the untangling operation, either resuming the predetermined drum movements associated with the drying cycle that was running before starting the untangling operation, or performing drum movements over time different from the predetermined drum movements associated with the drying cycle that was running before starting the untangling operation.

2. The method of claim 1 , wherein clothes tangling conditions are determined when the detected values exceed a predetermined threshold.

3. The method of claim 1 , wherein the step of determining that the clothes inside the drum are in tangling conditions comprises maintaining in a memory a reference parameter indicative of an expected behavior of temperature of the drying air exiting the drum over time during the drying cycle.

4. The method of claim 1 , wherein an expected temperature over time is adjusted according to values detected during the drying cycle.

5. The method of claim 4 , wherein the step of adjusting the expected temperature is performed at the beginning of the drying cycle, before the step of monitoring the detected values.

6. The method of claim 1 , further comprising the step of:
responsive to the anomaly of the detected values no longer showing any clothes tangling conditions,
suspending the untangling operation and resuming the predetermined drum movements associated with the drying cycle that was running before starting the untangling operation.

7. The method of claim 1 wherein said step of detecting values is performed using a sensor of the laundry dryer to detect the temperature of the air at or downstream of the outlet of the drum.

8. The method of claim 1 wherein at the end of the untangling operation, drum movements over time different from the predetermined drum movements associated with the drying cycle that was running before starting the untangling operation are performed, and further including the step of reducing the number of reversions of drum rotation and/or the time interval in which the drum rotates in reversed rotation direction and/or increasing/decreasing the drum rotation speed.

9. The method of claim 1 , wherein the steps of operating the laundry dryer are controlled by a microprocessor.

10. The method of claim 9 wherein:
at least one sensor is used for the step of detecting values indicative of temperatures during the drying cycle;
a microprocessor memory is used for storing the at least one reference parameter; and further comprising the steps of:
estimating a temperature of the clothes according to the detected values using the microprocessor; and
starting the untangling operation if the anomaly of the detected values with respect to the at least one reference parameter is identified.

Assignees

• Bison Alberto
• Cavarretta Francesco
• Ugel Maurizio
• Electrolux Home Products Corp Nv

Inventors

• Bison Alberto
• Cavarretta Francesco
• Ugel Maurizio

Classifications

• D06F2103/44

  Current or voltage · CPC title

• D06F2105/46

  Drum speed; Actuation of motors, e.g. starting or interrupting · CPC title

• D06F2103/08

  Humidity · CPC title

• D06F2103/34

  Humidity · CPC title

• D06F2058/2829

  Textiles & Paper · mapped topic