What is the working principle of a level sensor?
1. Hammerhead type level sensor
The hammer-type level sensor consists of a servo motor, a steel wire rope suspending the hammer, a level transmitter, and a digital display with a microcomputer. Upon startup, the microcomputer sends a hammer-lowering signal, causing the servo motor to rotate and lower the hammer. When the hammer touches the material surface, the transmitter sends a signal to the microcomputer, causing the hammer to pause its descent and sending a hammer-raising signal. The servo motor then reverses, raising the hammer and sending the level signal value to the digital display. After the hammer reaches the top of the silo, the motor stops, and after a delay, the above actions are repeated several times.
2. Nuclear radiation level sensor
The gamma rays emitted by the radioactive sources Co-60 and Cs-137 can penetrate the container walls and the material inside. A gamma ray receiver is installed on the lower side of the storage silo. As the height of the material surface changes, the intensity of the gamma rays after passing through the material layer also varies. The receiver detects the intensity of the incident gamma rays and displays the material level on a digital display.
It is a non-contact measurement method that does not require drilling holes in the container and thus avoids damaging it. Therefore, it is more suitable for accurate measurement of hazardous materials and in harsh environments such as high temperature and high pressure. Although gamma rays have harmful effects on the human body, there is no danger in limited doses with proper safety precautions.
3. Ultrasonic level sensor
An ultrasonic generator and receiver are installed at the top of the storage silo, directly facing the material surface. The ultrasonic waves emitted by the generator are reflected after passing through an air layer to the material surface; a small portion of the reflection is received by the receiver. The material level is calculated by multiplying the time it takes for the ultrasonic wave to travel from emission to reception by the speed of sound. Since air temperature affects the speed of sound propagation, accurate measurement of the air temperature is necessary to correct for the sound speed. Ultrasonic level sensors are particularly suitable for accurately measuring the level of larger block materials.
The above is an introduction to the working principle of level sensors. After reading this article, do you have a deeper understanding of level sensors? Currently, level sensor technology is relatively mature, and with the improvement of sensor science and technology, more intelligent and practical level sensor products will be launched in the future, gradually making greater contributions to modern industry!
