How to judge whether the water level sensor is good or bad?

- Aug 17, 2019-

The water level sensor includes common photoelectric type, floating ball type, capacitive type, probe type, and cable type, ultrasonic type etc. Each type of water level sensor works differently, so how to quickly find a suitable liquid sensor? How to judge the quality of the liquid sensor?


First of all, according to the application environment, if it is industrial grade, it can eliminate the float type. Usually, the industrial water treatment adopts the floating ball type, which is easy to cause false alarm and short life. Ultrasonics are used in industry, and photoelectric type can also be used in industrial liquid testing.


If it is a household appliance, the ultrasonic water level sensor can be excluded. The ultrasonic water level sensor has a blind zone with a certain distance, it has a requirement for the range and the volume of the container. If the container is too small, the measurement cannot be performed, therefore, ultrasonic level sensor can not be used like coffee machines, water dispensers, water purifier etc. The ultrasonic level sensor has the advantage of real-time detection, while other water level sensors can only install multiple probes on one measuring body to make a multi-point water level sensor, which cannot be detected in real time.


So how do you judge the quality of the water level sensor?

Mainly based on reliability and stability, the float-type water level sensor is particularly unstable, which is easily affected by the water level. Due to factors such as liquid viscosity, debris, and magnetic properties, such liquid level sensors have low liquid level detection accuracy and low reliability.


The capacitive touch sensorcan only be applied to non-metallic water tanks. The working principle is that the change of water level causes the capacitance change, so as to determine whether the sensor is in a water state or a waterless state.

The metal water tank can cause capacitive changes, which may lead to misjudgment, so the stability of such sensors is easily affected by other factors.


The infrared level detector refracts the infrared light emitted by the internal transmitting tube, and judges whether the sensor is in a water state according to the amount of photoelectric light received by the internal receiver. If only a small amount of light is received or is not received because the light is refracted in the water, it is judged to have a water state. Photoelectric type is affected by the working principle because it is infrared light, but has nothing to do with factors such as pressure, temperature, density, corrosivity, etc., and has little effect on the measured medium. Because of high repeatability and high detection accuracy, it has the characteristics of high reliability and long life.


The ultrasonic tank level sensor is characterized by its large size, and it is usually impossible to use an ultrasonic tank level sensor for household appliances and small equipment. Ultrasonic water level sensors are commonly used in industrial equipment with accurate liquid level detection and fast feedback signals.