Handheld Ultrasonic Gas Flow Meter The handheld ultrasonic gas flow meter employs ultrasonic technology for high-accuracy gas flow measurement, based on the time-of-flight difference between upstream and downstream ultrasonic paths (typical accuracy: ±1%). As ultrasonic waves travel through gas, their speed increases with the flow (e.g., +2 m/s) and decreases against it (e.g., –2 m/s). A microprocessor processes this time difference to compute flow velocity (range: 0.1–60 m/s). By integrating the pipe’s cross-sectional area, the device provides instantaneous flow readings (up to 10,000 m³/h) and cumulative flow data. Its non-contact measurement avoids pressure drop, and its lightweight, portable design (under 5 kg) allows for quick on-site setup—making it well-suited for gas utility inspections and industrial emission monitoring.