Which valve prevents transfilling between compressed-gas cylinders?

Which valve prevents transfilling between compressed-gas cylinders?

• A. Fail-safe valve
• B. Pop-off valve
• C. Pressure-sensor shutoff valve
• D. Check valve

Answer: (D)

The key idea is one-way flow. A check valve is a one-way device that only allows gas to move from the cylinder toward the downstream system and automatically closes to stop any reverse flow. When cylinders are connected to a shared manifold or distribution line, pressure from one cylinder can otherwise push gas back into another cylinder or into an unintended path. The check valve prevents that backflow, so no transfilling occurs between cylinders. Other valves have important safety roles but don’t address backflow between cylinders. A fail-safe valve works to ensure the patient’s gas mix isn’t compromised if oxygen pressure drops, not to stop flow in the reverse direction. A pop-off valve vents excess pressure to protect the system from over-pressurization. A pressure-sensor shutoff valve uses sensors to shut off flow when pressures are out of range. None of these are designed primarily to block backflow between cylinders, which is why the check valve is the correct choice.

The key idea is one-way flow. A check valve is a one-way device that only allows gas to move from the cylinder toward the downstream system and automatically closes to stop any reverse flow. When cylinders are connected to a shared manifold or distribution line, pressure from one cylinder can otherwise push gas back into another cylinder or into an unintended path. The check valve prevents that backflow, so no transfilling occurs between cylinders.

Other valves have important safety roles but don’t address backflow between cylinders. A fail-safe valve works to ensure the patient’s gas mix isn’t compromised if oxygen pressure drops, not to stop flow in the reverse direction. A pop-off valve vents excess pressure to protect the system from over-pressurization. A pressure-sensor shutoff valve uses sensors to shut off flow when pressures are out of range. None of these are designed primarily to block backflow between cylinders, which is why the check valve is the correct choice.