Exhaust type clothes dryer and method for controlling an exhaust type clothes dryer

Patent metadata

Field	Value
Publication number	US-9745690-B2
Application number	US-201514945832-A
Country	US
Kind code	B2
Filing date	Nov 19, 2015
Priority date	Dec 8, 2014
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A method for controlling an exhaust type clothes dryer may include measuring humidity of air passing through an interior of the drum to sense a degree of dryness of a target item, and discharging air that has passed through the drum or recirculating at least a portion of air that has passed through the drum to the drum by comparing a degree of dryness of the target item with a predetermined reference value. In the recirculating of air, an amount of recirculated air may be increased according to an increase in the degree of dryness of the target item by adjusting a degree of opening of a recirculation channel.

First claim

What is claimed is:

1. A method for controlling an exhaust type clothes dryer in which ambient air introduced from an outside of a case is heated by a heater, the heated air is supplied to a drum to dry a target item, and air that has passed through the drum is discharged to the outside of the case through an exhaust duct, the method comprising:
measuring, by a humidity sensor, relative humidity of air passing through an interior of the drum to sense a degree of dryness of the target item; and
discharging, by a controller, air that has passed through the drum, or recirculating at least a portion of air that has passed through the drum back to the drum by comparing the degree of dryness of the target item with a predetermined reference value, wherein, in the recirculating of air, when the relative humidity at an outlet of the drum is higher than 87.5%, air is discharged from the drum without recirculating any of the air back to the drum, and when the relative humidity is equal to or lower than 87.5%, the portion of air recirculated to the drum increases as the relative humidity decreases, wherein the portion of air is increased in stages.

2. The method of claim 1 , wherein the recirculating of at least the portion of air includes turning off the heater.

3. The method of claim 1 , wherein the degree of opening of the recirculation channel is adjusted by a damper rotatably provided at the recirculation channel and an actuator configured to rotate the damper to be opened and closed.

4. The method of claim 1 , wherein the humidity sensor includes an electrode sensor provided at an outlet of the drum and configured to sense a degree of dryness of the target item according to a voltage value changed according to an amount of moisture of the target item introduced to the interior of the drum.

5. The method of claim 4 , wherein the recirculating of at least the portion of air includes a plurality of predetermined recirculation modes such that amounts of recirculated air are different.

6. The method of claim 5 , wherein the controller compares predetermined reference voltage values according to the plurality of recirculation modes and a measurement value from the electrode sensor and adjusts the degree of opening of the recirculation channel according to a predetermined amount of recirculation air in a corresponding mode among the plurality of recirculation modes.

7. The method of claim 1 , wherein the humidity sensor is provided at an outlet of the drum and includes:
a dry-bulb temperature sensor configured to measure a dry-bulb temperature, and
a wet-bulb temperature sensor configured to measure a wet-bulb temperature.

8. The method of claim 7 , wherein the recirculating of at least the portion of air includes a plurality of predetermined recirculation modes such that amounts of recirculated air are different.

9. The method of claim 8 , wherein the controller calculates a relative humidity using measurement values measured by each of the dry-bulb temperature sensor and the wet-bulb temperature sensor, compares predetermined reference relative humidity values according to the plurality of recirculation modes and the relative humidity calculated using the measurement values, and adjusts the degree of opening of the recirculation channel according to a predetermined amount of recirculation air in a corresponding mode among the plurality of recirculation modes.

10. An exhaust type clothes dryer operated using the method of claim 1 .

11. An exhaust type clothes dryer, comprising:
a case;
a drum rotatably provided in the case;
an intake duct that introduces ambient air from outside of the case into the case and supplies heated air to the drum to dry a target item;
a heater that heats air in the intake duct;
a humidity sensor that measures a humidity of air passing through an interior of the drum to sense a degree of dryness of the target item;
an exhaust channel that discharges air that has passed through the drum to the outside of the case;
a blower provided inside of the exhaust channel;
a recirculation channel that recirculates air from the exhaust channel back to the drum; and
a controller that compares the degree of dryness of the target item with a predetermined reference value to control an amount of air that the exhaust channel discharges and an amount of recirculated air that the recirculation channel recirculates, wherein during the recirculating of air, when the relative humidity at an outlet of the drum is higher than 87.5%, the air passing through the drum is not recirculated into the drum but discharged to the outside of the case; and
when the relative humidity is equal to or lower than 87.5%, the amount of the air recirculated into the drum is gradually increased in stages as the relative humidity decreases.

12. The dryer of claim 11 , wherein the humidity sensor includes an electrode sensor provided at an outlet of the drum and configured to sense the degree of dryness of the target item according to a voltage value changed according to an amount of moisture of the target item introduced to the interior of the drum.

13. The dryer of claim 12 , wherein the humidity sensor is provided at an outlet of the drum and includes a dry-bulb temperature sensor and a wet-bulb temperature sensor configured to measure a dry-bulb temperature and a wet-bulb temperature, respectively, at the outlet of the drum.

14. The dryer of claim 13 , wherein the controller includes a plurality of predetermined recirculation modes to control the amount of recirculated air recirculated in the recirculation channel and discharged in the exhaust channel.

15. The dryer of claim 14 , wherein the controller is configured to calculate a relative humidity using measurement values measured by each of the dry-bulb temperature sensor and the wet-bulb temperature sensor, compare predetermined reference relative humidity values according to the plurality of recirculation modes and the relative humidity calculated using the measurement values, and adjust the degree of opening of the recirculation channel according to a predetermined amount of recirculation air in the corresponding mode among the plurality of recirculation modes.

16. The dryer of claim 11 , wherein the controller includes a plurality of predetermined recirculation modes to control the amount of recirculated air recirculated in the recirculation channel and discharged in the exhaust channel.

17. The dryer of claim 16 , wherein the controller is configured to compare predetermined reference voltage values according to the plurality of recirculation modes and a measurement value from the electrode sensor and adjust the degree of opening of the recirculation channel according to a predetermined amount of recirculation air in a corresponding mode among the plurality of recirculation modes.

18. The dryer of claim 11 , further including a damper rotatably provided in the recirculation channel that adjusts the degree of opening of the recirculation channel, and an actuator that rotates the damper to be opened and closed.

19. The dryer of claim 11 , wherein the controller includes a mode to turn off the heater.

Assignees

• Lg Electronics Inc

Inventors

• Lee Sunki
• Park Daeyun
• Ryoo Byeongjo

Classifications

• D06F2103/10

  expressed as capacitance or resistance · CPC title

• D06F2105/24

  Flow or velocity · CPC title

• D06F2103/36

  Flow or velocity · CPC title

• D06F2103/08

  Humidity · CPC title

• D06F58/02

  having dryer drums rotating about a horizontal axis · CPC title