High-accuracy ultrasonic gas flow meter based on time-difference method

The invention provides a high-accuracy ultrasonic gas flow meter based on a time-difference method. The high-accuracy ultrasonic gas flow meter is arranged in an X shape. A first ultrasonic transducer and a second ultrasonic transducer are arranged in a set and a third ultrasonic transducer and a fourth ultrasonic transducer are arranged in a set. The first ultrasonic transducer, the second ultrasonic transducer, the third ultrasonic transducer and the fourth ultrasonic transducer are connected to the input end of a one-out-of-four electronic switch, through section of the one-out-of-four electronic switch, output signals pass an amplification circuit, a filter circuit and a rectifying circuit sequentially and then are converted into square signals, and a time measurement circuit measures the period from the time when the ultrasonic transducers transmit square waves of high-voltage pulse signals to the time when the square signals of ultrasonic waves are received. The ultrasonic transmission time-difference principle is adopted for measurement, measurement is free of contact, tested gas is free of resistance or damage, echo signals of the ultrasonic waves are converted into the square waves, and the measurement accuracy is improved multiple times compared with existing measures.