Universal head-mix swirl injector for gas torch

1. A mixing injector for a gas torch, the mixing injector comprising:

an injector body adapted to be disposed in a head of the torch, the injector body comprising:

a central passageway running between first and second ends of the injector body, a first portion of said central passageway enclosing a swirl baffle;

a second portion of said central passageway including an injector orifice having a diameter that is smaller than a diameter of the first portion of said central passageway;

a third portion of said central passageway comprising a mixing chamber, the mixing chamber having a diameter larger than a diameter of the injector orifice and smaller than the diameter of the first portion of said central passageway, the swirl baffle, the injector orifice, and the mixing chamber sharing a common axis; and

a gas inlet port extending from a wall of the mixing chamber to an exterior of the injector body, the gas port for receiving fuel gas from a fuel gas supply and for directing said fuel gas to said mixing chamber.

2. The mixing injector of claim 1 , wherein the gas inlet port comprises a plurality of gas inlet ports.

3. The mixing injector of claim 1 , wherein the plurality of gas inlet ports are evenly spaced about a circumference of the injector body.

4. The mixing injector of claim 1 , wherein the gas inlet port has a diameter, and the gas inlet port is spaced a first distance from the transition between the second and third portions of the central passageway, wherein the first distance is equal to or less than two times the diameter.

5. The mixing injector of claim 1 , wherein the swirl baffle comprises a flat element twisted to resemble a corkscrew.

6. The mixing injector of claim 1 , the injector body further comprising first and second ends, the first end including threads for engaging cooperating threads in a gas torch head, the second end being generally cylindrical and sized to be received in close conformity with an inside diameter of a mixing oxygen tube.

7. The mixing injector of claim 1 , wherein a transition between the first and second portions of the central passageway comprises a first chamfer having a chamfer angle.

8. The mixing injector of claim 7 , wherein a transition between the second and third portions of the central passageway comprises a second chamfer having said chamfer angle.

9. A gas torch, comprising

a torch head, a cutting oxygen tube, a mixing oxygen tube, and a fuel gas tube; and

a mixing injector comprising an injector body coupled at a first end to the torch head, and at a second end to the mixing oxygen tube, the injector body comprising:

a central passageway running between first and second ends of the injector body, a first portion of said central passageway enclosing a swirl baffle;

a second portion of said central passageway including an injector orifice;

a third portion of said central passageway comprising a mixing chamber, the third portion having a diameter that is larger than a diameter of said second portion, the swirl baffle, the injector orifice, and the mixing chamber sharing a common axis; and

a gas inlet port extending from a wall of the mixing chamber to the fuel gas tube, the gas port for receiving fuel gas from the fuel gas tube and for directing said fuel gas to said mixing chamber.

10. The gas torch of claim 9 , wherein the gas inlet port has a port diameter, and the gas inlet port is spaced a first distance from the transition between the second and third portions of the central passageway, wherein the first distance is equal to or less than two times the port diameter.

11. The gas torch of claim 9 , wherein the gas inlet port comprises a plurality of gas inlet ports evenly spaced about a circumference of the injector body.

12. The gas torch of claim 9 , wherein the torch head includes a fuel gas port having a first portion in fluid communication with the fuel gas tube, the fuel gas port having a second portion in fluid communication with the gas inlet port of the injector body.

13. The gas torch of claim 9 , wherein a transition between the second and third portions of the central passageway comprises a chamfer.

14. A method for mixing gases within a head of a gas torch, the method comprising:

passing a first gas through a swirl baffle, the swirl baffle positioned directly adjacent the head of the gas torch;

passing the first gas from the swirl baffle into an injector orifice; and

passing the first gas from the injector orifice into a mixing chamber, the mixing chamber having a diameter larger than a diameter of the injector orifice, the swirl baffle, the injector orifice, and the mixing chamber sharing a common axis;

wherein passing the first gas from the injector orifice into the mixing chamber creates a pressure gradient that pulls a second gas into the mixing chamber through a gas port disposed in a wall of the mixing chamber.

15. The method of claim 14 , wherein passing a first gas through the swirl baffle comprises directing preheat oxygen from an oxygen source through a mixing oxygen tube in fluid communication with said swirl baffle.

16. The method of claim 14 , wherein the second gas is fuel gas, and the pressure gradient comprises a first pressure in the mixing chamber and a second pressure in the gas port, the first pressure being lower than the second pressure.

17. The method of claim 14 , wherein the first gas is oxygen, and the second gas is selected from the list consisting of acetylene, natural gas, propane, propylene qtane.

18. The method of claim 14 , comprising mixing the first and second gases in the mixing chamber.

19. The method of claim 14 , further comprising combining the mixed first and second gases with a supply of cutting gas in the torch head.