The non-contact flow sensor is able to calculate and output the instantaneous cross-sectional flow and cumulative flow based on the built-in software algorithm. It can also output the flow rate and water level. Measured information can be viewed on the upper platform. The intrinsically safe flow sensor can be used to monitor the water level, flow rate and flow capacity of roadways in mining areas. When the readings of the water level, flow rate and flow capacity exceed the set warning values or alarm values, alarm messages will be sent.