THE OXYHYDRIC PROCESS 73 



two nozzles through one of which a mixture of oxygen and 

 hydrogen is supplied, while the other delivers pure oxygen 

 only. 1 The action of the older apparatus is, however, to 

 actually melt the metal, and while very effective for its 

 purpose, it is impossible by it to produce a smooth and 

 exact cut of any desired length. 



With the present apparatus a preheating nozzle, deliver- 

 ing mixed oxygen and hydrogen, is used to continuously 

 heat the metal, while immediately following it, and set at 

 an angle such that both streams of gas strike the metal at 

 the same place, is a second nozzle delivering pure oxygen 

 only. This cuts the metal by oxidizing it without melting 

 and blows away the oxides by the force of the blast. The 

 result is a cut which may be fairly compared with that 

 made by a cutting tool, while the heating is so local that 

 the properties of the material cut are not affected beyond 

 about %4-inch of the cut surface and the width of the 

 kerf is surprisingly small. 



The oxyhydric process is based on the well-known fact 

 that iron burns easily and rapidly in an atmosphere of oxy- 

 gen gas, as much heat is thus set free. If we throw a jet of 

 oxygen upon iron that has been heated to red, the oxygen 

 oxidizes the metal, which is to say, burns it. Thus the steel 

 is heated only to from 1,300 to 1,500 F., as at this temp- 

 erature iron has a great affinity for oxygen, and the com- 

 bination produces different forms of oxides. 



The double-nozzle torch may be manipulated by hand, 

 or it may be guided by any sort of mechanical arrangement ; 

 and thin sheets or thick plates, steel tubes, structural 

 shapes, castings, or any odd pieces of steel may be easily 

 cut. 



The cut can be made to follow any sort of a line what- 

 ever, as all forms of curves and odd shapes are cut as 

 easily as the straight line. The cut is not necessarily 

 square to the surface, as a beveling cut can be easily made, 



'Acetylene is being used in this country in place of hydrogen, with 

 some makes of torches. 



