In an OAC torch, the oxygen-carrying tube for the cutting stream is the highest tube.

In an OAC torch, the oxygen-carrying tube for the cutting stream is the highest tube.

• A. Lowest tube
• B. Highest tube
• C. Middle tube
• D. No oxygen tube

Answer: (B)

In an oxy-acetylene cutting torch, different gas lines carry the fuel gas and the cutting oxygen, and their arrangement is designed so the cutting oxygen reaches the workpiece right where the cut begins. The oxygen-carrying tube being the highest tube means the cutting oxygen is delivered directly to the flame at the tip, after the workpiece has been preheated. This placement ensures the intense oxidizing jet interacts with the heated metal to form and sustain the cut, while keeping the preheat flame stable in the lower part of the flame. If the oxygen line weren’t the highest, it could mix with preheat gas too early or be too far from the nozzle to properly drive the cutting reaction, reducing efficiency or causing unsafe backflow.

In an oxy-acetylene cutting torch, different gas lines carry the fuel gas and the cutting oxygen, and their arrangement is designed so the cutting oxygen reaches the workpiece right where the cut begins. The oxygen-carrying tube being the highest tube means the cutting oxygen is delivered directly to the flame at the tip, after the workpiece has been preheated. This placement ensures the intense oxidizing jet interacts with the heated metal to form and sustain the cut, while keeping the preheat flame stable in the lower part of the flame. If the oxygen line weren’t the highest, it could mix with preheat gas too early or be too far from the nozzle to properly drive the cutting reaction, reducing efficiency or causing unsafe backflow.