Dual firing rate flame sensing system
AssigneeHoneywell Inc.
InventorJohn L. Erdman
Life of this patent
Estimating the term…
Abstract
A flame rod inserted in a flame created by the secondary air supplied to a burner is used to generate a flame signal voltage. This flame signal voltage fluctuates with the amount of secondary air available and with the fuel supplied. These fluctuations are relied upon by an integrated control system that utilizes a microprocessor or microcomputer to safely control an induced draft-type of furnace.
Claims10
A flame sensing system adapted to control a fuel burner in a furnace which includes a fuel supply means to vary a supply of fuel between a low flow rate and a high flow rate, and air source means adapted to vary a supply of combustion air to the burner between a high flow rate and a low flow rate, including:
- a flame rod positioned to be in an outer area of a flame present at said burner when said burner is in operation;
- flame sensing circuit means adapted to be energized by a source of voltage;
- and said flame sensing circuit means connected to said flame rod and said burner to provide a flame rectified sensing signal that varies with the rate of fuel being burned and connected to said fuel supply means and said air source means to control said fuel supply means and said air source means between said high flow rates and said low flow rates.
A flame sensing system adapted to control a fuel burner in a furnace which includes a fuel supply means to vary a supply a fuel between a low flow rate and a high flow rate, and air source means adapted to vary a supply of combustion air to the burner between a high flow rate and a low flow rate, including:
- a flame rod positioned to be in an outer area of a flame present at said burner when said burner is in operation;
- flame sensing circuit means adapted to be energized by a source of voltage;
- said flame sensing circuit means connected to said flame rod and said burner to provide a flame rectified sensing signal that varies with the rate of fuel being burned and connected to said fuel supply means and said air source means to control said fuel supply means and said air source means between said high flow rates and said low flow rates;
- and integrated furnace control system means connected to said flame sensing circuit, said fuel supply means, and said air source means to control said fuel burner, in part, in response to said flame rectified sensing signal.
Dependencies are inferred from the claim text.