As the orifice of the thrope tube widens, what change is required to maintain a constant pressure?

• A. Less flow
• B. Equal flow
• C. Greater flow
• D. Variable flow

Answer: (C)

To maintain a constant pressure in a system as the orifice of the Thorpe tube widens, an increase in flow rate is necessary. This relationship can be understood through the principles of fluid dynamics, particularly relating to the behavior of gases in open systems.

When the diameter of the orifice increases, the resistance to flow decreases, allowing gas to pass through more easily. To keep the pressure constant at this point in the system, the flow rate must be increased to compensate for the reduced resistance. This ensures that the flow velocity and the volume of gas delivered remain consistent despite the widening orifice.

In practical terms, if the flow rate does not increase with the widening orifice, the pressure would invariably drop due to the increased capacity for flow without adequate input, which is counterproductive in a medical setting where consistent delivery of anesthetic gases is critical.