Gas mixing apparatus for blowpipes

Claim 1

A BLOWPIPE COMPRISING A BODY HAVING AT ONE END AN EXTERNALLY-COMMUNICATING CAVITY OF RELATIVELY LARGE DIAMETER TERMINATING IN A FLAT BASE SURFACE, AND A DISCHARGE PASSAGE OF RELATIVELY SMALL DIAMETER AT THE OTHER END OF A COMBUSTIBLE GAS MIXTURE LEADING FROM SAID CAVITY IN AXIAL ALIGNMENT THEREWITH; A MIXER SECURED IN SAID EXTERNALLY-COMMUNICATING CAVITY HAVING A FLAT END FACE SPACED A SHORT DISTANCE FROM AND PARALLEL TO SAID BOTTOM SURFACE TO PROVIDE A SHALLOW MIXING CHAMBER, SAID MIXER ALSO HAVING TWO LONGITUDINAL PASSAGES FOR FUEL AND COMBUSTION-SUPPORTING GASES GREATER IN DIAMETER THAN THE DEPTH OF SAID SHALLOW MIXING CHAMBER AND LESS THAN THE DIAMETER OF SAID DISCHARGE PASSAGE AND HAVING ORIFICES SPACED FROM ONE ANOTHER IN SAID FLAT END FACE ON OPPOSITE SIDES OF SAID DICHARGE PASSAGE IN POSITION TO DISCHARGE STREAMS OF FUEL GAS AND COMBUSTION-SUPPORTING GAS AGAINST SAID FLAT BOTTOM SURFACE TO BE DEFLECTED RADIALLY INWARD TOWARD AND INTO ONE ANOTHER TO FORM A COMBUSTIBLE GAS MIXTURE; AND MEANS FOR SUPPLYING FUEL GAS TO ONE AND COMBUSTION-SUPPORTING GAS TO THE OTHER OF SAID LONGITUDINAL PASSAGES THROUGH SMALL DIAMETER METERING PORTS OF CROSS-SECTIONAL AREA SUBSTANTIALLY LESS THAN THAT OF SAID LONGITUDINAL PASSAGES.