Apparatus for sensing dryness degree in exhaust type clothes dryer and control method using same

• US 20040060197A1
• Filed: 07/15/2003
• Published: 04/01/2004
• Est. Priority Date: 01/20/2001
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Soon-Jo, Jeong, Hae-Deog
• Granted Patent: US 6,931,759 B2
• Time in Patent Office: Days
• US Class Current: 34/595
• CPC Class Codes: D06F 2103/08 Humidity
• CPC Class Codes: D06F 2103/10 expressed as capacitance or resistance
• CPC Class Codes: D06F 2103/32 Temperature
• CPC Class Codes: D06F 2105/28 Electric heating
• CPC Class Codes: D06F 34/18 Condition of the laundry, e.g. nature or weight
• CPC Class Codes: D06F 34/26 Condition of the drying air, e.g. air humidity or temperature
• CPC Class Codes: D06F 58/38 of drying, e.g. to achieve the target humidity

Abstract

An apparatus for sensing a dryness degree in an exhaust type clothes dryer and a control method using the same, includes an electrode sensor for sensing a clothes drying state based on the humidity of the clothes in the drum, and a thermistor for sensing the temperature of the air discharged after drying the clothes. By comparing the clothes drying state and discharged air temperature, the operation of the dryer is controlled, so that the drying of clothes can be accurately performed, thus to improve efficiency and performance of an exhaust type clothes dryer.

Claims

1. An apparatus for sensing dryness degree in exhaust type clothes dryer comprising:

a humidity sensing unit positioned inside a drum and sensing a dryness state of clothes by allowing a voltage value to be changed according to the humidity of clothes;

a temperature sensing unit positioned at the side of a discharge hole of the drum, drying the clothes and sensing a temperature of the air being exhausted; and

a control unit for receiving sense signals from the humidity sensing unit and the temperature sensing unit and determining a dryness degree of the clothes.

2. The apparatus of claim 1, wherein an exhaust duct is connected to one side of the drum to outwardly discharge air used for drying the clothes, and the temperature sensing unit is positioned in the exhaust duct.

3. The apparatus of claim 2, wherein a blower is installed in the exhaust duct to forcibly discharge the air used for drying the clothes in the drum, and the temperature sensing unit is positioned at the side of a discharge portion of the blower.

4. The apparatus of claim 2, wherein the humidity sensing unit is positioned at an entrance of the exhaust duct.

5. The apparatus of claim 1, wherein the humidity sensing unit refers to an electrode sensor formed as two metal plates are positioned side by side and a voltage value is varied according to humidity, and the temperature sensing unit is formed as a thermistor that an electric resistance value differs according to a temperature change.

6. The apparatus of claim 1, further comprising:

a suction air sensing unit disposed at the side of the suction hole of the drum, sensing a temperature of air sucked into the drum and inputting it to the control unit.

7. A drying control method of an exhaust type dryer, comprising the steps of:

sensing a dryness state value of clothes by a humidity sensing unit;

sensing a temperature value of air being discharged after drying the clothes by a temperature sensing unit; and

comparing the dryness state value and the temperature value of the discharged air, and controlling the operation of the dryer.

8. The method of claim 7, wherein a drying completion time point is determined to stop the operation of the dryer by comparing the dryness state value and temperature value of the discharged air.

9. The method of claim 7, wherein after the clothes drying operation starts, the operation of the dryer is controlled with the dryness state value sensed by the humidity sensing unit until the clothes in the drum reaches a set dryness degree value, and at values above the set dryness degree value, the operation of the dryer is controlled with the temperature value of the discharge air sensed by the temperature sensing unit.

10. The method of claim 9, wherein the dryness degree value is set as a value obtained by drying clothes by 80%.

11. The method of one of claims 7 through 10, wherein when the discharged air temperature value reaches a set temperature, it is determined to be a drying completion time point.

12. The method of one of claims 7 through 10, wherein the heater on/off operation, that when the discharged air temperature value reaches a set upper limit temperature, the heater discontinues its operation, while when the discharged air temperature value reaches a set lower limit temperature, the heater is operated again, is repeatedly performed as many as the set number of times, so as to complete the drying.

13. The method of claim 12, wherein the heater on/off operation repetition number of times is set depending on the amount of clothes to be dried.

14. The method of claim 12, wherein the heater on/off operation repetition number of times is set depending on the quality of clothes to be dried.