Red Seal Instrumentation and Control Technician Practice Exam

Which device is commonly used to measure flow rate in liquids?

1. Pressure transducer

2. Thermocouple

3. Flowmeter

4. Capacitance sensor

The correct answer is: Flowmeter

Flowmeters are specifically designed to measure the flow rate of liquids and gases. They operate based on various principles, such as the displacement of a fluid, the velocity of a fluid, or other mechanisms that correlate with the flow rate. There are several types of flowmeters, including mechanical types like turbine and positive displacement flowmeters, as well as electronic types like electromagnetic and ultrasonic flowmeters. In industrial applications, accurate flow measurement is crucial for process control, efficiency, and safety. Flowmeters can provide real-time data that helps in monitoring and controlling the flow within piping systems, ensuring processes function smoothly. While pressure transducers can provide information that may correlate with flow under certain conditions (such as in pressure drop flow measurement), they do not inherently measure flow rate directly. Similarly, thermocouples are used for temperature measurement, and capacitance sensors are generally used for level or humidity measurement, not for flow. Thus, the flowmeter stands out as the primary device employed for measuring flow rates in liquids.