Microwave appliance and a method for operating the same

1. A microwave appliance, comprising:

a casing that defines a chamber configured for receipt of food items for cooking and a circulation conduit, the circulation conduit having an inlet and a single outlet in fluid communication with ambient atmosphere within a room housing the microwave appliance;

a door mounted to the casing and configured for permitting selective access to the chamber of the casing;

a fan positioned within the circulation conduit of the casing, the fan drawing a flow of air into the circulation conduit through the inlet of the circulation conduit when the fan is in an activated state;

an air filter configured for removing relatively small particles mounted to the casing within the circulation conduit of the casing at the outlet of the circulation conduit such that the flow of air within the circulation conduit passes through the air filter when the fan is in the activated state;

a sensor mounted to the casing, the sensor configured for measuring an air quality of the flow of air within the circulation conduit;

a grease filter configured for removing relatively large particles positioned within the circulation conduit of the casing at the inlet of the circulation conduit; and

a controller in operative communication with the fan and the sensor, the controller configured for:

operating the fan in order to draw the flow of air through the circulation conduit of the casing;

measuring the air quality of the flow of air within the circulation conduit with the sensor during said step of operating;

stopping the fan if an elapsed time interval since said step of operating exceeds a maximum on time; and

deactivating the fan if the air quality of the flow of air within the circulation conduit exceeds a threshold value at said step of measuring.

2. The microwave appliance of claim 1 , wherein the air filter comprises a charcoal air filter, a high-efficiency particulate air filter, or an electrostatic air filter.

3. The microwave appliance of claim 1 , wherein the sensor is positioned within the circulation conduit of the casing.

4. The microwave appliance of claim 1 , wherein the sensor comprises an optical dust sensor.

5. The microwave appliance of claim 4 , wherein the optical dust sensor is configured for measuring a quantity of particles within the flow of air in the circulation conduit in order to determine the air quality of the flow of air within the circulation conduit.

6. The microwave appliance of claim 5 , wherein said step of measuring comprises measuring the quantity of particles within the flow of air in the circulation conduit with the optical dust sensor during said step of operating, and said step of deactivating comprises deactivating the fan if the quantity of particles within the flow of air in the circulation conduit drops below a predetermined amount at said step of measuring.

7. The microwave appliance of claim 1 , wherein said step of deactivating comprises deactivating the fan if the air quality of the flow of air within the circulation conduit exceeds the threshold value at said step of measuring unless an elapsed time interval since said step operating does not exceed a minimum on time.

8. The microwave appliance of claim 1 , wherein the casing extends between a top portion and a bottom portion along a vertical direction, the inlet of the circulation conduit positioned at the bottom portion of the casing, the outlet of the circulation conduit positioned at the top portion of the casing.

9. The microwave appliance of claim 1 , wherein the casing is positioned above a range appliance along a vertical direction.

10. A method of operating a microwave appliance, comprising:

operating a fan of the microwave appliance in order to draw a flow of air through a circulation conduit of the microwave appliance such that the flow of air passes through an air filter mounted within the circulation conduit and subsequently passes out of the microwave appliance to mix with ambient atmosphere within a room housing the microwave appliance;

measuring an air quality of the flow of air within the circulation conduit with a sensor of the microwave appliance during said step of operating;

stopping the fan of the microwave appliance if an elapsed time interval since said step of operating exceeds a maximum on time; and

deactivating the fan of the microwave appliance when the air quality of the flow of air within the circulation conduit of the microwave appliance exceeds a threshold value at said step of measuring unless an elapsed time interval since said step operating does not exceed a minimum on time.

11. The method of claim 10 , wherein said step of measuring comprises measuring a quantity of particles within the flow of air in the circulation conduit with the sensor of the microwave appliance during said step of operating, and said step of deactivating comprises deactivating the fan of the microwave appliance if the quantity of particles within the flow of air in the circulation conduit drops below a predetermined amount at said step of measuring.

12. The method of claim 10 , wherein said step of operating comprises operating the fan of the microwave appliance in order to draw the flow of air through the circulation conduit of the microwave appliance and an air filter of the microwave appliance.

13. The method of claim 12 , wherein the air filter comprises a charcoal air filter, a high-efficiency particulate air filter, or an electrostatic air filter.