Which of the following devices is commonly used for continuous level measurement?

Radar level transmitters are widely used for continuous level measurement due to their ability to provide accurate readings without being affected by the properties of the material being measured, such as temperature, pressure, or density. This technology operates by emitting microwave signals towards the surface of the material. The time taken for the signal to return is then converted into a distance measurement, allowing for continuous monitoring of the level.

For level measurement applications, radar transmitters can be particularly advantageous since they can be used in various conditions, including in tanks with turbulent surfaces or in scenarios involving vapor or dust. This makes them suitable for a range of industries, such as oil and gas, water treatment, and chemical processing, where accurate level monitoring is critical for safety and efficiency.

The other devices, while important in their respective applications, do not serve the same primary function as radar level transmitters. Thermocouples are designed for temperature measurement, flow meters measure the rate of fluid flow in pipes, and pressure gauges assess the pressure within a system rather than continuously measuring levels.

Therefore, radar level transmitters stand out as the appropriate choice for continuous level measurement in a variety of contexts.