Oxy–acetylene welding gas usage: If a neutral flame is used throughout oxy–acetylene welding and both cylinders have the same capacity, will the oxygen and acetylene cylinders empty at approximately the same time?

Introduction / Context:
Flame chemistry in oxy–fuel processes depends on the volumetric ratio of oxygen to acetylene. A neutral flame, commonly used for welding steels, aims for an approximately 1:1 volumetric ratio, producing neither oxidising nor carburising conditions. Gas consumption rates follow from this ratio.

Given Data / Assumptions:

• Neutral flame with oxygen-to-acetylene ratio near 1:1.
• Welding (not cutting), where there is no separate cutting oxygen jet.
• Cylinders of equal nominal gas capacity.

Concept / Approach:
In welding with a neutral flame, the oxygen flow approximately equals acetylene flow. Therefore, if both cylinders start full and capacities are equal, their effective consumption causes both to deplete at roughly the same time. Deviations can occur due to regulator settings, nozzle size, or minor ratio tuning, but the principle stands. In contrast, oxy–fuel cutting uses an additional high-flow oxygen jet, making the oxygen cylinder empty much faster than the acetylene cylinder.

Step-by-Step Solution:
Set neutral flame: O2 flow ≈ C2H2 flow.Assume equal cylinder capacities and similar delivery conditions.Consumption parity implies similar depletion times.Therefore, the statement is correct for welding under neutral flame.

Verification / Alternative check:
Practice notes from welding manuals show oxygen and acetylene usage close to 1:1 for neutral welding flames, unlike cutting operations.

Why Other Options Are Wrong:
“Incorrect” confuses welding with cutting, where extra oxygen is used.

Injector or equal-pressure torches do not change the basic flame ratio for neutrality.

Nozzle size affects absolute flow but not the neutral ratio condition.

Common Pitfalls:
Assuming cutting ratios for welding; running slightly oxidising for speed and then observing faster oxygen depletion; ignoring that cylinder “capacity” references stored gas mass, not just pressure.

Final Answer:
Correct