What is the role of the indicator float in a rotameter?

• A. To adjust gas pressure
• B. To indicate flow rate
• C. To purify the gas
• D. To cool the gas

Answer: (B)

The indicator float plays a crucial role in a rotameter by providing a direct visual indication of the flow rate of gas or liquid passing through the device. As the gas flows through the rotameter, it lifts the float to a position that corresponds to the rate of flow. The height of the float is calibrated to a scale marked alongside the rotameter, allowing clinicians to easily read and interpret the flow rate. This functionality is essential for maintaining accurate dosing and ensuring patient safety during procedures requiring precise gas flow.

Other options do not accurately describe the function of the indicator float. Adjusting gas pressure is typically managed by separate regulators or valves, while purification of gases usually involves filters or scrubbers, not rotameters. Cooling gas is a different process involving heat exchanges or coolers and is not related to the flow measurement provided by the rotameter.