Automatic liquid fuel burner control

Claim 1

IN A LIQUID FUEL BURNING SYSTEM OF THE TYPE WHICH INCLUES A RETURN FUEL FLOW BURNER, AN AUTOMATIC AIR FUEL FEED CONTROL APPARATUS COMPRISING IN COMBINATION: A SOURCE OF LIQUID FUEL UNDER PRESSURE AND A MAIN LINE CONNECTING SAID SOURCE TO THE BURNER; A SOURCE OF PRIMARY COMBUSTION AIR UNDER PRESSURE ALSO CONNECTED TO THE BURNER; MEANS FOR CONTROLLING THE AMOUNT OF AIR FED TO SAID BURNER IN ACCORDANCE WITH THE TEMPERATURE OF A SUBSTANCE TO BE HEATED THEREBY; MODULATING FUEL VALVE MEANS MECHANICALLY BIASED TOWARD CLOSED POSITION; MEANS CONNECTING SAID SOURCE OF AIR TO URGE SAID VALVE TOWARD CLOSED POSITION; MEANS CONNECTING THE RETURN LIQUID FUEL LINE FROM SAID BURNER TO SAID VALVE IN A DIRECTION TO URGE SAID VALVE TO OPEN POSITION; MEANS CONNECTED TO THE OPPOSITE SIDE OF SAID VALVE FOR RETURNING LIQUID FUEL PASSING THERETHROUGH TO SAID SOURCE OF LIQUID FUEL UNDER PRESSURE; AND MEANS DEFINING AN ORIFICE SIZED TO CREATE A PREDETERMINED PRESSURE DROP CONNECTED BETWEEN SAID MAIN LIQUID FUEL LINE AND SAID RETURN LINE ON THE BURNER SIDE OF SAID VALVE; WHEREBY THE BACK PRESSURE IN THE FUEL RETURN LINE IS CONTROLLED INVERSELY AS THE COMBUSTION AIR PRESSURE AND A POSITIVE FUEL FLOW IS MAINTAINED FOR ALL RATES OF COMBUSTION OF THE BURNER.