Systems and methods of detecting an obstructed furnace air filter using a flame sensor

Patent metadata

Field	Value
Publication number	US-12013135-B2
Application number	US-202016986453-A
Country	US
Kind code	B2
Filing date	Aug 6, 2020
Priority date	Aug 6, 2020
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

The disclosed technology includes systems and methods for detecting an at least partially obstructed air filter in a furnace. The disclosed technology can include a system and method that can receive temperature data from a flame sensor configured to detect a temperature of a flame in a burner, determine that an air filter associated with the burner is at least partially obstructed by determining that the temperature data indicates the flame temperature is greater than or equal to a threshold temperature, and output an alarm signal indicating that the air filter is at least partially obstructed.

First claim

What is claimed is:

1. A non-transitory, computer-readable medium having instructions stored thereon that, when executed by one or more processors, cause a system to:
receive, from a flame sensor, temperature data indicative of a temperature of a flame in a burner;
determine, based at least in part on the temperature data, that the temperature of the flame in a burner is greater than a first threshold temperature;
determine, based at least in part on the temperature data, that the temperature of the flame is greater than a second threshold temperature, wherein the second threshold temperature is higher than the first threshold temperature;
in response to the temperature of the flame being greater than both the first threshold temperature and the second threshold temperature, determine that an air filter associated with a mixing chamber is at least partially obstructed, wherein the mixing chamber is coupled to the burner;
output an alarm signal indicating that the air filter is at least partially obstructed;
output, via a controller, a first signal to a first fuel valve coupled to the mixing chamber;
output, via the controller, a second signal to a second fuel valve coupled to the burner; and
based on the first signal and the second signal, at least partially close the first and the second fuel valves.

2. The non-transitory, computer-readable medium of claim 1 , wherein the threshold temperature comprises a temperature value greater than or equal to approximately 1900° F. and less than approximately 2000° F.

3. The non-transitory, computer-readable medium of claim 1 , wherein the second threshold temperature comprises a temperature greater than or equal to 2000° F.

4. The non-transitory, computer-readable medium of claim 1 , wherein:
determining that the air filter is at least partially obstructed further comprises:
determining, based at least in part on the temperature data, that the temperature of the flame is greater than or equal to the threshold temperature for a predetermined amount of time; and

the instructions, when executed by the one or more processors, further cause the system to:
output the alarm signal indicating that the air filter is at least partially obstructed in response to determining that the temperature of the flame is greater than or equal to the threshold temperature for the predetermined amount of time.

5. The non-transitory, computer-readable medium of claim 4 , wherein:
determining that the air filter is at least partially obstructed further comprises:
determining, based at least in part on the temperature data, that the temperature of the flame is greater than or equal to a second threshold temperature for a second predetermined amount of time; and

the instructions, when executed by the one or more processors, further cause the system to:
output a control signal for a fuel valve associated with the burner to at least partially close.

6. The non-transitory, computer-readable medium of claim 1 , wherein the second threshold temperature is equal to the threshold temperature.

7. The non-transitory, computer-readable medium of claim 5 , wherein the second threshold temperature is greater than the threshold temperature.

8. The non-transitory, computer-readable medium of claim 5 , wherein the second predetermined amount of time is equal to the predetermined amount of time.

9. The non-transitory, computer-readable medium of claim 5 , wherein the second predetermined amount of time is greater than the predetermined amount of time.

10. A furnace having an air filter obstruction detection system, the furnace comprising:
an air inlet;
an air filter for filtering out particles in air passing through the air inlet;
an air moving device configured to move the air from the air inlet, through the air filter, and toward a combustion chamber;
a burner coupled to a mixing chamber and the combustion chamber and configured to create a flame by burning a mixture of fuel and the air;
a first fuel valve coupled to the mixing chamber and configured to direct the fuel into the mixing chamber;
a second fuel valve coupled to the burner;
a flame sensor configured to detect a temperature of the flame; and
a controller configured to:
receive temperature data from the flame sensor;
determine, based at least in part on the temperature data, that the temperature of the flame is greater than or equal to a first threshold temperature;
in response to determining that the temperature of the flame is greater than or equal to the first threshold temperature, determine that the air filter is at least partially obstructed;
output an alarm signal indicating that the air filter is at least partially obstructed;
send a first signal to the first fuel value;
send a second signal to the second fuel valve; and
cause, based respectively on the first signal and the second signal, the first and the second fuel valves to at least partially close.

11. The furnace of claim 10 , wherein the controller is further configured to send at least the first signal, based at least in part on determining that the temperature of the flame is greater than or equal to a second threshold temperature.

12. The furnace of claim 11 , wherein the second threshold temperature is greater than the first threshold temperature.

13. The furnace of claim 10 , wherein the flame sensor is a thermocouple.

14. The furnace of claim 10 , wherein the controller is further configured to:
determine, based at least in part on the temperature data, that the temperature of the flame is greater than or equal to the threshold temperature for a predetermined amount of time; and
output the alarm signal indicating that the air filter is at least partially obstructed in response to determining that the temperature of the flame is greater than or equal to the threshold temperature for the predetermined amount of time.

15. The furnace of claim 14 , wherein the controller is further configured to:
determine, based at least in part on the temperature data, that the temperature of the flame is greater than or equal to the threshold temperature for a second predetermined amount of time; and
output a control signal for the fuel valve to at least partially close.

16. The furnace of claim 14 , wherein the controller is further configured to:
determine, based at least in part on the temperature data, that the temperature of the flame is greater than or equal to a second threshold temperature for a second predetermined amount of time; and
output a control signal for the fuel valve to at least partially close.

17. The furnace of claim 16 , wherein the second threshold temperature is greater than the threshold temperature.

Assignees

• Rheem Mfg Co

Inventors

• Farley Darryl

Classifications

• F24F11/52

  Indication arrangements, e.g. displays · CPC title

• F23N2229/00

  Flame sensors · CPC title

• F23N2225/16

  burner temperature · CPC title

• B01D46/0086

  Filter condition indicators · CPC title

• F24H3/006

  using fluid fuel · CPC title