Ultrasonic sensor working principle is: piezoelectric crystal composition of the ultrasonic sensor is a reversible sensor, it can be converted into mechanical oscillation of electrical energy to produce ultrasonic waves, and at the same time in the reception of ultrasonic waves can also be converted into electrical energy.
Ultrasonic wave is a kind of mechanical oscillation in elastic medium, there are two forms: transverse oscillation (transverse wave) and longitudinal oscillation (longitudinal wave). In industrial applications mainly use longitudinal oscillation. Ultrasonic waves can propagate in gases, liquids and solids at different speeds.
In addition, it also has refraction and reflection phenomena, and there is attenuation in the propagation process. In the air propagation of ultrasound, its frequency is low, generally tens of KHZ, while in the solid, liquid frequency is available higher. Faster attenuation in the air, while in the liquid and solid propagation, attenuation is smaller, spread farther. The use of ultrasound characteristics, can be made into a variety of ultrasonic sensors, with different circuits, made of a variety of ultrasonic measuring instruments and devices, and in communications, medical home appliances and other aspects of a wide range of applications.
Specific applications of ultrasound:
1, ultrasonic sensors can detect the container state. The ultrasonic sensor installed in the plastic melt tank or plastic granule room on top, to the container inside the sound waves, you can accordingly analyze the status of the container, such as full, empty or half-full and so on.
2, ultrasonic sensors can be used to detect transparent objects, liquids, any surface rough, smooth, light dense material and irregular objects. But not for outdoor, hot environment or pressure tanks and foam objects.
3, ultrasonic sensors can be used in food processing plants, the realization of the closed-loop control system for the detection of plastic packaging. With the new technology can be detected in the wet ring such as bottle washing machine, noise environment, temperature extremely drastic changes in the environment.
4, ultrasonic sensors can be used to detect the liquid level, detection of transparent objects and materials, control tension and measurement of distance, mainly for the packaging, bottle making, material handling inspection of coal equipment transportation, plastics processing and automotive industry. Ultrasonic sensors can be used for process monitoring to improve product quality, detect defects, determine the presence or absence, and more.
Refer to Baidu Encyclopedia - Ultrasonic sensors