What types of water level sensors are of poor quality?

- Mar 03, 2020-

The water tank mechanical float switch is of poor quality among many liquid level sensors, and it has the advantage of being cheap, so it is widely used in various fields. However, the reliability of the water tank mechanical float switch is relatively low, prone to the issue that the float is stuck, and the accuracy is not accurate. After using for a period of time, the phenomenon often occurs.


The water tank mechanical float switch uses the water level to rise and fall, which drives the float to rise and fall with it. There is a ring magnet inside the float. As the float moves up and down, it will drive the internal reed switch to open and close. It is a mechanical product, so its reliability is easily affected by external factors.


For example, the magnet easily adsorbs scale impurities and causes scale, the scale attached to the surface of the float will cause the weight of the float to increase, and the weight of the float will cause deviations in its level control accuracy. In addition, there is a disadvantage, float level sensor has a loose structure.

The water tank mechanical float switch cannot be used in liquids that are viscous or have impurities inside, because the viscous liquid will cause the float to jam. Impurities and particles contained in the liquid entering between the float and the pipe column will also cause the float to jam and cause defects.


The photoelectric single point level sensor uses the optical principle to detect the liquid level. All the components inside have been sealed with glue and there are no moving parts, so the reliability is high. The float level sensor accuracy can only be controlled within the range of ± 3mm, with a total difference of 6mm. The photoelectric liquid level sensor can be controlled within the range of ± 1mm.


The photoelectric single point level sensor has a small volume, takes up a small space, and has a simple installation process. It only needs to be screwed into the water tank. For the problems of scale and air bubbles, the photoelectric level sensor can be avoided by software.


The price of the float-type water level sensor is not much different from that of the photoelectric single point level sensor. Considering all aspects of installation process, accuracy, and reliability, the photoelectric water-level sensor is the best choose.