How does the Thorpe Tube measure true flow?

The Thorpe Tube measures true flow by maintaining a constant pressure of the gas source. This device operates based on the principle of variable orifice flow measurement, where the gas from the source enters the tube and raises a float positioned within the tube. The height of the float corresponds to the flow rate of gas passing through the tube.

By maintaining a constant pressure at the gas source, the flow rate can be accurately measured regardless of changes in upstream conditions. This ensures that measurements reflect true flow, as variations in gas pressure would otherwise alter the flow rate and potentially lead to inaccurate readings. The design thus allows for precise regulation and measurement of gas flow in medical applications, which are essential for patient care and safety.