Rotatable-drum laundry drier and method of controlling a rotatable-drum laundry drier

Patent metadata

Field	Value
Publication number	US-9255359-B2
Application number	US-201113990147-A
Country	US
Kind code	B2
Filing date	Nov 28, 2011
Priority date	Nov 29, 2010
Publication date	Feb 9, 2016
Grant date	Feb 9, 2016

Abstract

A method for controlling a rotatable-drum laundry drier to dry laundry in a drum is provided. The control method includes the steps of memorizing, in a memory device of the laundry drier, a comparison threshold variable in time according to a predetermined profile, and, at predetermined drying times in the laundry drying cycle, measuring an electric quantity indicating the moisture in the laundry at the drying time; comparing, at each drying time, the measured electric quantity with the memorized comparison threshold corresponding to the drying time; and determining the end of drying cycle time on the basis of this comparison.

First claim

The invention claimed is:

1. A control method for controlling a rotatable-drum laundry drier to dry laundry in a drum, said control method comprising the steps of:
memorizing, in a memory device of said laundry drier, a comparison threshold which is variable in time according to a predetermined profile,
starting a laundry drying cycle, and
at predetermined drying times) in the laundry drying cycle:
measuring an electric quantity indicating the moisture in the laundry at the drying time;
comparing, at each drying time, the measured electric quantity with the memorized comparison threshold corresponding to the drying time;
determining the end of drying cycle time on the basis of said comparison; and
terminating the drying cycle based on the determined end of drying cycle time.

2. A control method as claimed in claim 1 , wherein the end of drying cycle time corresponds to the drying time at which said measured electric quantity reaches said comparison threshold.

3. A control method as claimed in claim 1 , wherein said comparison threshold is variable in time according to a predetermined discrete profile.

4. A control method as claimed in claim 3 , wherein said predetermined discrete profile comprises a number of different threshold values, each corresponding to a predetermined drying time interval and to a predetermined laundry quantity/weight.

5. A control method as claimed in claim 1 , wherein the comparison threshold is variable in time according to a predetermined continuous profile.

6. A control method as claimed in claim 1 , wherein said electric quantity is the resistance/conductance/impedance measured between at least two measuring electrodes positioned in such a way to contact the laundry in the drum.

7. A control method as claimed in claim 1 , further comprising the steps of:
calculating the laundry quantity/weight on the basis of the comparison threshold corresponding to the end of drying cycle time; and
adjusting the duration of a laundry cooling stage, subsequent to the end of drying cycle time, on the basis of the calculated laundry quantity/weight.

8. A rotatable-drum laundry drier comprising:
a rotatable drum defining a drying chamber for laundry;
a heating device for feeding hot air to the drum to dry laundry therein;
a memory device in which a comparison threshold, which is variable in time according to a predetermined profile, is memorized; and
an electronic control unit configured to:
start a laundry drying cycle;
measure an electric quantity indicating the moisture in the laundry in the drum at a drying time;
compare said measured electric quantity with the comparison threshold corresponding to said drying time;
determine the end of drying cycle time on the basis of said comparison; and
terminate the drying cycle based on the determined end of drying cycle time.

9. A rotatable-drum laundry drier as claimed in claim 8 , wherein the end of drying cycle time corresponds to the drying time at which said measured electric quantity reaches said comparison threshold.

10. A rotatable-drum laundry drier as claimed in claim 8 , wherein said comparison threshold is variable in time according to a predetermined discrete profile.

11. A rotatable-drum laundry drier as claimed in claim 8 , wherein said predetermined discrete profile comprises a number of different threshold values, each corresponding to a predetermined drying time interval and to a laundry quantity/weight.

12. A rotatable-drum laundry drier as claimed in claim 8 , wherein said comparison threshold is variable in time according to a predetermined continuous profile.

13. A rotatable-drum laundry drier as claimed in claim 8 , wherein said electric quantity is the resistance/conductance/impedance measured between two electrodes contacting the laundry.

14. A rotatable-drum laundry drier as claimed in claim 8 , wherein said electronic control unit is configured to calculate the laundry quantity/weight on the basis of the comparison threshold corresponding to the end of drying cycle time, and to adjust the duration of a laundry cooling stage, subsequent to the end of drying cycle time, on the basis of the calculated laundry quantity/weight.

15. An electronic control unit for controlling a rotatable-drum laundry drier, and configured to implement a control method as claimed in claim 1 .

16. A control method as claimed in claim 2 , wherein said comparison threshold is variable in time according to a predetermined discrete profile.

17. A control method as claimed in claim 16 , wherein said predetermined discrete profile comprises a number of different threshold values, each corresponding to a predetermined drying time interval and to a predetermined laundry quantity/weight.

18. A control method as claimed in claim 2 , wherein the comparison threshold is variable in time according to a predetermined continuous profile.

19. A control method as claimed in claim 2 , wherein said electric quantity is the resistance/conductance/impedance measured between at least two measuring electrodes positioned in such a way to contact the laundry in the drum.

20. A control method as claimed in claim 3 , wherein said electric quantity is the resistance/conductance/impedance measured between at least two measuring electrodes positioned in such a way to contact the laundry in the drum.

Assignees

• Altinier Fabio
• Bisaro Michele
• Ragogna Roberto
• Electrolux Home Prod Corp

Inventors

• Altinier Fabio
• Bisaro Michele
• Ragogna Roberto

Classifications

• D06F2103/08

  Humidity · CPC title

• D06F2103/10

  expressed as capacitance or resistance · CPC title

• D06F2101/14

  Time settings · CPC title

• D06F58/38

  of drying, e.g. to achieve the target humidity · CPC title

• D06F2058/2819

  Textiles & Paper · mapped topic