If the bobbin in the O2 rotameter is not rotating, this most likely indicates what?

If the bobbin in the O2 rotameter is not rotating, this most likely indicates what?

• A. A flow of N2O through the O2 rotameter
• B. No flow of O2 through the O2 rotameter
• C. A flow of O2 through the O2 rotameter that is markedly lower than indicated
• D. A leak in the O2 rotameter above the bobbin

Answer: (B)

The float (bobbin) in an O2 rotameter rises and orients itself under the influence of the gas flow. The motion of the bobbin is driven by the airflow; when there is no flow, there is no stream to move or spin it, so it stays at the bottom and does not rotate. Therefore, a bobbin that isn’t rotating most likely means there is no O2 flowing through that rotameter. Other scenarios, like N2O flowing through the O2 path, would involve crossflow issues and usually would show other signs or require the system’s crossover to be active; a small or reduced O2 flow would still generate some bobbin movement, and a leak above the bobbin wouldn’t inherently stop rotation.

The float (bobbin) in an O2 rotameter rises and orients itself under the influence of the gas flow. The motion of the bobbin is driven by the airflow; when there is no flow, there is no stream to move or spin it, so it stays at the bottom and does not rotate. Therefore, a bobbin that isn’t rotating most likely means there is no O2 flowing through that rotameter.

Other scenarios, like N2O flowing through the O2 path, would involve crossflow issues and usually would show other signs or require the system’s crossover to be active; a small or reduced O2 flow would still generate some bobbin movement, and a leak above the bobbin wouldn’t inherently stop rotation.