Dryer control method and apparatus using the same

• US 6,931,760 B2
• Filed: 07/09/2004
• Issued: 08/23/2005
• Est. Priority Date: 11/03/2003
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Yang, Jae Suk
• Primary Examiner(s): GRAVINI, STEPHEN MICHAEL
• Application Number:
  US10/887,092
• Publication Number:
  US 20050091876A1
• Time in Patent Office: 410 Days
• Field of Search: 344/91, 344/945, 34/28, 345/75, 346/06, 307/650, 134/93, 68/17.R
• US Class Current: 34/491
• CPC Class Codes: D06F 2101/16 Target humidity for the drying process, e.g. very-dry cycles
• CPC Class Codes: D06F 2103/06 Type or material
• CPC Class Codes: D06F 2103/10 expressed as capacitance or resistance
• CPC Class Codes: D06F 2103/18 Washing liquid level
• CPC Class Codes: D06F 2103/38 Time, e.g. duration
• CPC Class Codes: D06F 2105/56 Remaining operation time; Remaining operational cycles
• CPC Class Codes: D06F 58/38 of drying, e.g. to achieve the target humidity
• CPC Class Codes: D06F 58/46 Control of the operating time

Abstract

A dryer control method provides for selection among a plurality of dryness levels so that the user may select a desired degree of dryness for any given type of laundry. The method includes steps of selecting one among a plurality of dryness levels; driving a drying unit holding laundry; sensing a value indicative of a water content of the laundry; comparing the sensed value with first and second predetermined values; measuring a time required for the sensed value to reach the second predetermined value from the first predetermined value; computing a drying time based on the measured time; and stopping the driving step upon expiration of the computed drying time, wherein the first and second predetermined values determine a reference value corresponding to the selected dryness level.

Claims

1. A dryer control method comprising steps of:

driving a drying unit which holds laundry;

sensing a value indicative of a water content of the laundry;

determining whether the sensed value reaches a first predetermined value;

measuring an amount of time required for the sensed value to reach a second predetermined value from the first predetermined value;

computing a drying time based on the measured time; and

stopping said driving step upon expiration of the computed drying time.

2. The dryer control method as claimed in claim 1, further comprising a step of selecting a dryness level, wherein the first and second predetermined values determine a reference value corresponding to the selected dryness level.

3. The dryer control method as claimed in claim 2, wherein the drying time is computed by an equation t=C₁+C₂Δ

T, where t is the drying time, C₁ is a constant, C₂ is a constant according to a dryness level, and Δ

T is the measured time.

4. The dryer control method as claimed in claim 3, wherein the constant C₁ is an offset value.

5. The dryer control method as claimed in claim 4, wherein the offset value is zero.

6. The dryer control method as claimed in claim 2, wherein the dryness level is selected according to laundry type.

7. An automatic dryer comprising:

a drying unit for holding and drying laundry;

a sensor for sensing a water content of the laundry and outputting a value indicative of the sensed water content of the laundry; and

a controller configured to control said drying unit according to a measured amount of time, wherein the measured time is a time required for said sensor output value to rise by a reference amount.

8. The automatic dryer as claimed in claim 7, wherein the reference amount corresponds to one of a plurality of selectable dryness levels.

9. The automatic dryer as claimed in claim 8, further comprising:

a timer, controlled by said controller, for measuring the measured time; and

a memory for storing a lookup table which stores a plurality of reference values corresponding to the plurality of selectable dryness levels.

10. The automatic dryer as claimed in claim 9, wherein the lookup table further stores a dryness constant C₂ corresponding to one of the plurality of selectable dryness levels.

11. The automatic dryer as claimed in claim 10, wherein the dryness constant is stored according to a laundry type.

12. The automatic dryer as claimed in claim 11, wherein the lookup table further stores an arbitrary constant C₁ indicative of an offset for each laundry type.

13. The automatic dryer as claimed in claim 7, wherein said drying unit comprises:

a rotatable drum for holding the laundry;

an electric heater for heating external air and forcing the heated air inside said rotatable drum;

a blower fan for circulating the air of the drum; and

an electric motor for rotating said blower fan and said rotatable drum.

14. The automatic dryer as claimed in claim 7, wherein said sensor is a moisture sensor.

15. The automatic dryer as claimed in claim 7, wherein said sensor outputs a linear voltage value from 0V to 5V indicative of a water content of the laundry.