Fuel gas fired heater with automatic damper means

Claim 1

IN A FUEL GAS FIRED HEATER: MEANS FOR INDUCING A FLOW OF AIR THROUGH SAID HEATER; MEANS FOR DELIVERING FUEL GAS TO SAID HEATER UNDER PRESSURE; A BURNER DEFINING A PLU-RALITY OF BURNER PORT OPENINGS FOR RECEIVING AND DIVIDING A PORTION OF SAID AIR INTO A PLURALITY OF INDIVIDUAL COMBUSTION AIR STEAMS AND GAS ESCAPE ORIFICE MEANS FOR INTRODUC-ING FUEL GAS INTO SAID AIR STREAMS; AND A MOVABLE AIR CONTROL DAMPER SUPPORTED IN SAID HEATER ALONGSIDE OF SAID BURNER IN SAID AIR STREAM, AND INCLUDING MEANS YIELDINGLY BIASING THE DAMPER TO A NORMALLY CLOSED POSITION PREVENTING SAID FLOW OF AIR FROM BY-PASSING SAID BURNER, SAID DAMPER RESPONSIVE TO INCREASED AIR PRESSURE THEREAGAINST TO BE SHIFTED TO PROGRESSIVELY MORE OPEN POSITIONS PER-MITTING INCREASING AMOUNTS OF AIR FLOWING THROUGH THE HEATER TO BY-PASS SAID BURNER IN DIRECT PROPORTION TO THE INCREASE IN AIR PRESSURE DIFFERENTIAL ACROSS SAID DAMPER TO THEREBY MAINTAIN THE RATE OF FLOW OF SAD COMBUSTION AIR THROUGH SAID BURNER PORT OPENINGS SUBSTANTIALLY CONSTANT DURING VARIATIONS IN THE TOTAL RATE OF FLOW OF AIR THROUGH SAID HEATER.