System and method for detecting moisture content in a dryer appliance

Patent metadata

Field	Value
Publication number	US-10669667-B2
Application number	US-201815968791-A
Country	US
Kind code	B2
Filing date	May 2, 2018
Priority date	May 2, 2018
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

A dryer appliance and a method of detecting a moisture content of clothes in the dryer appliance are provided. The dryer appliance includes a top bearing positioned proximate a front of a rotating drum and temperature and humidity sensors positioned behind the top bearing for measuring a chamber temperature and humidity as well as a temperature sensor for measuring the exhaust temperature. A controller implements a method of detecting the moisture content of clothes within the drum by obtaining the chamber and exhaust temperatures and the chamber humidity, estimating the moisture content using these values, and adjusting at least one operating parameter of the dryer appliance in response to the estimated moisture content of the clothes.

First claim

What is claimed is:

1. A method of detecting a moisture content of clothes in a dryer appliance, the dryer appliance comprising a drum defining a chamber, a chamber temperature sensor being positioned proximate a top of the drum, an exhaust temperature sensor, and a humidity sensor being positioned proximate a top of the drum, the method comprising:
measuring a chamber temperature using the chamber temperature sensor and an exhaust temperature using the exhaust temperature sensor;
measuring a chamber humidity using the humidity sensor;
estimating the moisture content of the clothes in the dryer appliance using the chamber temperature, the exhaust temperature sensor, and the chamber humidity; and
adjusting at least one operating parameter of the dryer appliance in response to the estimated moisture content of the clothes,
wherein estimating the moisture content comprises using the following polynomial regression equation:
VD Sat ( T C )=−0.0003· T C 3 +0.0353· T C 2 −0.0152· T C +4.0905

where: T C is the measured chamber temperature (in ° C.); and
VD Sat is a saturation vapor density.

2. The method of claim 1 , wherein estimating the moisture content comprises using a psychometric table to determine the saturation vapor density.

3. The method of claim 2 , wherein using the psychometric table comprises formulating the polynomial regression equation for calculating the saturation vapor density as a function of the chamber temperature.

4. The method of claim 1 , wherein estimating the moisture content comprises using the following equation to determine the chamber vapor density:

VD
C

=

RH
C

·

VD
Sat

100

where: RH C is the measured chamber humidity;
VD Sat is the saturation vapor density; and
VD C is a vapor density in the chamber.

5. The method of claim 1 , wherein the at least one operating parameter is adjusted when the measured exhaust temperature exceeds a temperature threshold and an estimated outlet humidity drops below a humidity threshold, wherein the estimated outlet humidity is calculated using the following equation:

RH
OUT

=

100
·

VD
C

VD

Sat
⁢
_
⁢
OUT

where: RH OUT is the estimated outlet humidity;
VD Sat_OUT is the saturation vapor density at the exhaust; and
VD C is a vapor density in the chamber.

6. The method of claim 5 , wherein the temperature threshold and the humidity threshold are determined as a function of at least one of a load size, a load type, and a dryer air flow rate.

7. The method of claim 1 , wherein adjusting at least one operating parameter of the dryer appliance comprises:
initiating a cool down cycle where a heating element is turned off and an air handler continues to circulate air through the chamber for a predetermined cooling time.

8. The method of claim 7 , wherein the predetermined cooling time is empirically determined as the amount of time necessary to drop the chamber temperature below a temperature threshold.

9. The method of claim 1 , wherein adjusting at least one operating parameter of the dryer appliance comprises:
initiating a timed dry segment where a heating element remains on and an air handler continues to circulate air through the chamber for a predetermined fixed time.

10. The method of claim 1 , comprising:
detecting an operating issue based on the measured humidity.

11. The method of claim 10 , wherein detecting the operating issue comprises:
determining that the measured humidity has remained substantially constant for a predetermined time.

12. The method of claim 10 , wherein the operating issue is a clogged filter, an empty drum, a flow restriction to the humidity sensor, or an improper load size.

13. The method of claim 1 , wherein the chamber temperature sensor and the humidity sensor are positioned within a top bearing of the dryer appliance.

14. The method of claim 13 , wherein the chamber temperature sensor and the humidity sensor are positioned on an inner surface of the top bearing outside the chamber, and wherein the top bearing defines a plurality of holes to permit chamber air to contact the chamber temperature sensor and the humidity sensor.

15. A dryer appliance comprising:
a cabinet;
a drum rotatably mounted within the cabinet, the drum defining a chamber for receipt of clothes for drying;
a top bearing positioned proximate a front of the drum;
a chamber temperature sensor positioned within the top bearing for measuring the chamber temperature;
an exhaust temperature sensor positioned within a trap duct for measuring an exhaust temperature;
a humidity sensor positioned within the top bearing for measuring the chamber humidity; and
a controller operably coupled to the chamber temperature sensor, the exhaust temperature sensor, and the humidity sensor, the controller configured for:
obtaining the chamber temperature using the chamber temperature sensor;
obtaining the exhaust temperature using the exhaust temperature sensor;
obtaining the chamber humidity using the humidity sensor;
estimating a moisture content of the clothes in the dryer appliance using the chamber temperature, the exhaust temperature, and the chamber humidity; and
adjusting at least one operating parameter of the dryer appliance in response to the estimated moisture content of the clothes,
wherein estimating the moisture content comprises using the following equation to determine a chamber vapor density:

V
⁢

⁢

D
C

=

R
⁢

⁢

H
C

·
V

⁢

⁢

D
Sat

100

where: RH C is the measured chamber humidity;
VD Sat is a saturation vapor density; and
VD C is a vapor density in the chamber.

16. The dryer appliance of claim 15 , wherein the chambe

Assignees

• Haier Us Appliance Solutions Inc

Inventors

• Prajescu Ionelia Silvia
• Gonzalez Giancarlo Hazael Paez
• Lopez Julio Alberto Anaya
• Andres Carlos Humberto Reyes

Classifications

• D06F58/28 Primary

  Textiles & Paper · mapped topic

• D06F58/02

  having dryer drums rotating about a horizontal axis · CPC title

• D06F2058/2854

  Textiles & Paper · mapped topic

• D06F2058/2861

  Textiles & Paper · mapped topic

• D06F2058/2819

  Textiles & Paper · mapped topic