Development of a Ultrasonic Instrument for the Sealed Container's Liquid Level Measurement

Ultrasonic is one of the effective methods in the field of liquid level measurement. In the process of ultrasonic propagation, reflection and refraction will occur on the interface of the two different mediums. The reflectance ratio depends on the relative acoustic impedance of the two mediums. This character of the ultrasonic is used in the measurement of the sealed container's liquid level and an instrument system based on programmed software is developed. Firstly the structure and the principle of work of the system are presented. Then the transmitting and receiving circuit is designed. After that the software is developed by the secondary development of the data acquisition card. And at last the developed instrument is applied to the liquid level measurement of the air-condition compressor used in the passenger train car. The developed instrument provides an effective method for the liquid level measurement of the sealed container. And because of its modular structure, the instrument can be easily transplanted to other relative fields