In addition, in recent years, several liquid level sensors, including continuous liquid level sensor, intelligent liquid level sensor and pressure sensor, are introduced Intelligent liquid level transmitter combined with mechanism.
1. Pressure type liquid level sensor (input type liquid level transmitter)
The input type liquid level transmitter generally adopts semiconductor membrane box structure, which has the functions of self inspection, self diagnosis and remote transmission. The use of metal sheet to accept liquid pressure and transfer the sealed silicone oil pressure to semiconductor strain gauge for pressure type liquid level sensor is more and more widely used. In recent years, it has been developed with small volume, wide temperature range, good reliability and high precision Pressure type liquid level sensor Liquid level measurement. Due to the improvement of the performance of solid state pressure sensor (piezoresistive bridge type) and the development of micro processing technology. Input type liquid level transmitter should be very wide. This type of drop in level sensor can also be used for corrosive liquids, as shown in the figure above.
2. Ultrasonic liquid level sensor
A non-contact liquid level sensor is widely used. Its working principle is that when it works, it emits a beam of ultrasonic wave to the surface of the powder or is reflected by it. The sensor receives the reflected wave again. If the sound velocity is constant, the distance between the absorber and the liquid surface (powder surface) can be calculated according to the time of sound wave return, that is, the position of liquid surface (powder surface) can be measured. It can measure the liquid level under the working condition of agitator.
3. Laser liquid level sensor
Its working principle is the same as that of ultrasonic liquid level sensor. Near infrared light is usually used in laser liquid level sensor. The other part of the light emitted through the semi transmission mirror of the laser through the optical system disposal into a certain width of parallel beam on the surface of the object. The reflected wave reaches the receiving part of the sensor and then converts it into an electrical signal. Because the time from irradiation to receiving is very short, the output laser is processed by semi transmission mirror.
4. Plug in capacitive liquid level transmitter
Capacitive liquid level sensor has two conductor electrodes. The static capacitance changes due to the gas, fluid or solid between the electrodes. The capacitive liquid level sensor can be controlled by microcomputer to realize automatic adjustment and has the function of self diagnosis to realize high reliable information transmission. Because the capacitive liquid level sensor has no mechanical movable part, it is easy to operate and its shape and structure are free. Therefore, it is widely used.
5. Automatic balance liquid level sensor
This kind of liquid level sensor can measure the liquid level by detecting the change of buoyancy of the balance float. It can be equipped with a microcomputer so that it can be used to measure the liquid level of large span with high precision. In addition, with the development of science and technology, in recent years, digital intelligent liquid level sensor has appeared, which combines the sensor technology with microprocessor intelligent liquid level transmitter. This article originates from Zetian sensing Please keep the source.