SYSTEMS AND METHODS FOR CONTROLLING GAS PRESSURE TO GAS-FIRED APPLIANCES

• US 20080124668A1
• Filed: 10/18/2006
• Published: 05/29/2008
• Est. Priority Date: 10/18/2006
• Status: Active Grant

• Current Assignee: Ademco Inc. (Resideo Technologies, Inc.)
• Original Assignee: Honeywell International Inc.
• Inventors: Schultz, Michael W., Bergum, Glenn R.
• Granted Patent: US 8,635,997 B2
• Time in Patent Office: Days
• US Class Current: 431/89
• CPC Class Codes: F23N 1/027 using mechanical means
• CPC Class Codes: F23N 2233/04 with variable speed
• CPC Class Codes: F23N 2241/02 Space-heating

Abstract

Systems and methods for controlling gas to gas-fired appliances are disclosed. An illustrative system can include a modulating gas valve adapted to supply gas to a burner unit, an inducer fan adapted to produce a combustion air flow at the burner unit, a pressure reducing element in fluid communication with the gas valve and adapted to output at least one pressure signal for sensing the combustion air flow outputted by the inducer fan, and a controller for controlling the speed of the inducer fan. The pressure reducing element can include a venturi tube, flow nozzle, or other suitable device capable of producing pneumatic signals that can be used by the gas valve to modulate the gas supplied to the burner unit. By pneumatically linking the gas valve to the actual combustion air flow, the gas valve can be operated over a wide range of firing rates by adjusting the speed of the inducer fan.

Claims

1. A system for controlling gas pressure to a gas-fired appliance, the system comprising:

a modulating gas valve adapted to supply gas to a burner unit;

a multi or variable speed inducer fan adapted to produce a combustion air flow at the burner unit;

a pressure reducing element in fluid communication with the modulating gas valve, the pressure reducing element adapted to output at least one pressure signal for sensing said combustion air flow; and

a controller for controlling the speed of the inducer fan.

2. The system of claim 1, wherein the gas valve is adapted to modulate gas flow to the burner unit based on the combustion air flow produced by the inducer fan.

3. The system of claim 1, wherein the gas valve includes at least one regulator for regulating the gas supplied to the burner unit.

4. The system of claim 1, wherein the pressure reducing element includes a venturi tube.

5. The system of claim 1, wherein the pressure reducing element includes a flow nozzle.

6. The system of claim 1, wherein the pressure reducing element is located downstream of the inducer fan.

7. The system of claim 1, wherein the pressure reducing element is located upstream of the inducer fan.

8. The system of claim 1, wherein the amplitude of said at least one pressure signal is proportional to the combustion air flow produced by the inducer fan.

9. The system of claim 1, wherein said at least one pressure signal comprises a differential pressure signal including a first pressure signal and a second pressure signal lower than said first pressure signal.

10. The system of claim 9, further comprising:

a first pneumatic line in fluid communication with the gas valve, the first pneumatic line adapted to communicate the first pressure signal to the gas valve; and

a second pneumatic line in fluid communication with the gas valve, the second pneumatic line adapted to communicate the second pressure signal to the gas valve.

11. The system of claim 1, wherein the controller comprises an integral furnace controller in communication with one or more thermostat units.

12. The system of claim 1, wherein said gas-fired appliance comprises a warm air furnace.

13. A system for controlling gas pressure to a gas-fired appliance, the system comprising:

a modulating gas valve adapted to supply gas to a burner unit;

a multi or variable speed inducer fan adapted to produce a combustion air flow at the burner unit;

a venturi in fluid communication with the modulating gas valve, the venturi adapted to output at least one pressure signal for sensing said combustion air flow; and

a controller for controlling the speed of the inducer fan based at least in part on heat demand signals from one or more communicating thermostats.

14. A method of controlling gas pressure to a gas-fired appliance, the appliance including a multi or variable speed inducer fan adapted to produce a combustion air flow at a burner unit, the method comprising the steps of:

providing a pressure reducing element in fluid communication with the combustion air flow produced by the inducer fan;

sensing the pressure at the pressure reducing element and outputting at least one pressure signal to a modulating gas valve adapted to supply gas to the burner unit; and

adjusting the speed of the inducer fan to control the firing rate of gas supplied by the gas valve to the burner unit.

15. The method of claim 14, wherein the pressure reducing element includes a venturi tube.

16. The method of claim 14, wherein the pressure reducing element includes a flow nozzle.

17. The method of claim 14, wherein the pressure reducing element is placed downstream of the inducer fan.

18. The method of claim 14, wherein the pressure reducing element is placed upstream of the inducer fan.

19. The method of claim 14, wherein said step of adjusting the speed of the inducer fan is accomplished with a controller adapted to receive heat demand signals from one or more communicating thermostats.

20. The method of claim 14, wherein the amplitude of said at least one pressure signal is in proportion to the combustion air flow produced by the inducer fan.