Which statement describes a single-stage regulator's pressure behavior?

Which statement describes a single-stage regulator's pressure behavior?

• A. It maintains a constant delivery pressure from full to empty cylinders.
• B. It exhibits a slight rise in delivery pressure from full to empty cylinders.
• C. It only functions with oxygen and acetylene.
• D. It has two pressure stages.

Answer: (B)

A single-stage regulator reduces cylinder pressure in one step and doesn’t compensate for large changes in the cylinder’s pressure as it empties. Because the regulation is done in a single stage with a fixed spring, the balance between inlet pressure, the valve, and the spring shifts as the cylinder pressure falls. That shift causes the delivery pressure to drift upward slightly over the life of the cylinder. So, as the cylinder goes from full to empty, the outlet pressure tends to rise a little. This is in contrast to two-stage regulators, which keep the delivery pressure much more constant across the cylinder’s range.

A single-stage regulator reduces cylinder pressure in one step and doesn’t compensate for large changes in the cylinder’s pressure as it empties. Because the regulation is done in a single stage with a fixed spring, the balance between inlet pressure, the valve, and the spring shifts as the cylinder pressure falls. That shift causes the delivery pressure to drift upward slightly over the life of the cylinder. So, as the cylinder goes from full to empty, the outlet pressure tends to rise a little. This is in contrast to two-stage regulators, which keep the delivery pressure much more constant across the cylinder’s range.