The doppler ultrasonic flow meter adopts contactless measurement. It is simple to install, convenient, and easy to maintain. It is suitable for measuring liquids in pipelines that contain tiny particles, impurities or air bubbles. Precise, stable & reliable, this flow meter is applicable in the sewage and wastewater to detect the flow rate of water in pipelines. The doppler ultrasonic flow meter (EPF) transmits pulse waves to the pipeline through a sensor. The pulse wave signal is reflected after encountering particles in the liquid or air and is then received by the sensor. Based on the changing values of the frequency, the movement speed of the particles can be calculated. The average flow rate is therefore calculated using a set flow field data.