Principle of Water Level Sensor

Water level sensor is a kind of sensor which can detect water level. It is mainly used in medical, food and chemical industries to control water level and detect water level. There are many kinds of water level sensors, including single flange hydrostatic/double flange differential pressure water level sensor, floating ball water level sensor, magnetic water level sensor, input water level sensor, electric inner floating ball water level sensor, electric buoy water level sensor, capacitive water level sensor, magnetostrictive water level sensor, servo water level sensor, ultrasonic water level sensor, radar water level sensor, etc. Sensors, etc. The working principles of different water level sensors are different, and their applicability is different.

This paper briefly introduces the principles of these water level sensors. Buoy type water level transmitter is to change magnetic buoy into buoy. Water level sensor is designed according to Archimedes buoyancy principle. Buoy-type water level transmitter is used to measure the water level, boundary or density of liquid by means of tiny metal film strain sensing technology. It can be operated by the on-site buttons to perform routine setting operation. Floating ball water level transmitter consists of magnetic float ball, measuring duct, signal unit, electronic unit, junction box and installation parts. Generally, the proportion of magnetic float ball is less than 0.5. It can float above the liquid surface and move up and down along the measuring duct. There are measuring elements in the duct. It can convert the measured water level signal into resistance signal proportional to the change of water level under the action of external magnetic field and electronics. The unit is converted into signal output. Because the float switch is the simplest and oldest detection method, it has the disadvantage of inaccurate water level detection, and the float is easy to get stuck.

The hydrostatic water level sensor works on the principle of hydrostatic pressure measurement. It usually uses silicon pressure sensor to convert the measured pressure into electrical signal, which is amplified and compensated by amplifier circuit. Finally, it is output by 4-20 mA or 0-10 mA current mode.

The ultrasonic water level sensor is generated by the vibration of the transducer wafer under the excitation of voltage. When the ultrasonic wave touches the liquid, it will produce a significant reflection and form an echo. Therefore, the ultrasonic wave is used as a means of detection to produce and receive the ultrasonic wave. This is the working principle of the ultrasonic water level sensor. The characteristics of the ultrasonic water level sensor are: high frequency, short wavelength, small diffraction phenomenon, especially good direction, and it can be directed as a ray. Photoelectric liquid level sensor is a new type of contact point liquid level measurement and control device based on the principle that light reflects and refracts at the interface of two different media. Photoelectric water level sensor has many advantages, such as simple structure, high positioning accuracy, no mechanical parts, no debugging, high sensitivity, corrosion resistance, low power consumption, small size, etc. It also has the characteristics of high temperature resistance, high pressure resistance, strong corrosion resistance, stable chemical properties, and little impact on the measured medium.

Photoelectric water level sensor has a wide range of applications, high detection accuracy, long life and strong stability, so it is suitable for many aspects. Next, we will focus on the photoelectric liquid level sensor. Photoelectric water level sensor is a new type of contact point water level measurement and control device based on the principle that light reflects and refracts at the interface of two different media. It has many advantages such as simple structure, high positioning accuracy, no mechanical parts, no debugging, high sensitivity and corrosion resistance, less power consumption, small size and so on, which are gradually recognized by the market. Because the output of water level is only related to whether the photoelectric probe contacts the liquid level or not, and has nothing to do with other characteristics of the medium, such as temperature, pressure, density, electricity and other parameters, the photoelectric water level sensor has accurate detection, high repetition accuracy, fast response speed, very accurate liquid level control, and no need to adjust. Also it can be directly installed and used.

Because the photoelectric water level sensor probe is relatively compact, it can be separately installed in a narrow space for special tanks or containers. In addition, a number of photoelectric probes can be installed on a measuring body to make a multi-point water level sensor.

Because there are no mechanical moving parts in the photoelectric level switch, the photoelectric level sensor has high reliability, long life and maintenance-free. And because the principle of optical reflection is used to detect, photoelectric water level sensor is affected by scale, impurities, liquid corrosion and so on.