Which device is used to monitor the fuel level in a storage tank?

The device used to monitor the fuel level in a storage tank is the fuel level sensor. This instrument measures the amount of fuel within the tank and provides accurate readings, which are crucial for maintaining operational efficiency and safety. It typically employs float mechanisms or electronic components to detect fuel levels and can provide real-time data, alerts when levels are low, and help in planning fuel deliveries.

The pressure gauge, while important for monitoring pressure in systems, does not measure fuel levels directly. A temperature sensor is utilized to monitor the temperature of the fuel but is not designed for level assessment. The flow meter measures the rate of fuel flow through pipes, serving a different purpose than monitoring levels within a static tank. Thus, the fuel level sensor is specifically designed for this task, making it the correct choice.