Non-contact sealed vessel liquid level measurement and device design based on ultrasonic principle

From time to time, it is necessary to measure the level of certain sealed containers in life. These containers are usually filled with liquids that are flammable and explosive, toxic and hazardous, or highly volatile. In this paper, a non-contact online liquid level detection device is designed using the ultrasonic principle. The method is based on the unequal transmission and reflection coefficients of the liquid and gaseous media inside the measured vessel to achieve the measurement of the vessel level height. The device adjusts the amplification of the ultrasonic transmitting probe and receiving probe through the combination of micro controller software and hardware to achieve the measurement of the liquid level of containers with different materials and thicknesses. Separate level and height measurements of the vessel are achieved by two ultrasonic circuits. The device is equipped with a three-axis attitude sensor to observe the tilt condition of the container while measuring the container height. The final measured data can be displayed on the serial assistant, cell phone APP, and Ali cloud platform in multiple directions. The experiment proved that the device can measure containers with a thickness of less than 2 mm and that the height error is within 2 mm. The device has stable measurement data and is suitable for level measurement of small sealed vessels.