Float water level sensor is a common water level sensor, which is cheap and easy to operate. But its disadvantage is poor reliability, and it is prone to stuck or undesirable floats. There are many types of water level sensors, and there are many price and function that can replace float water level sensors. The more common ones are photoelectric water level sensors and capacitive water level sensors.
The prices of photoelectric water level sensors and capacitive water level sensors are similar to those of float water level sensors, and they are both relatively inexpensive sensors. These two kinds of sensors are superior to the float water level sensor in terms of reliability and accuracy, which can be seen in the working principle and evaluation of many users.
The float water level sensor usually has the phenomenon of stuck floating ball and inaccurate accuracy after a period of use. The reason lies in its working principle and structural design. The float water level sensor uses the rise and fall of the water level to drive the movement of the float, and the rise and fall of the float will drive the reed switch to open and close, and the reed switch is turned on or off according to the on/off of the reed switch. The float water level sensor is a mechanical product, so the reliability is relatively poor, and the accuracy is relatively poor. Except that the float ball is easily stuck and cannot move, the internal structure of the float water level sensor has a ring magnet, which is easy to absorb impurities in the water to form scale. The scale will increase the weight of the float and affect its accuracy. In addition, the float level sensor also has the disadvantages of large volume, loose and complex structure, and inconvenient cleaning.
The photoelectric water level sensor uses the principle of optical reflection to detect the liquid level. There will be an infrared emitting tube and a receiving tube inside the photoelectric water level sensor. The emitting tube will emit light, and the light will be reflected back to the receiving tube through the light cone on the top of the sensor. When the sensor head is submerged in water, the receiving tube will receive some or no light. At this time, the sensor will give a signal and judge it as a water state. When the sensor head is not in contact with water, the receiving tube will receive all the light, and the sensor will give a signal to judge it as an anhydrous state.
The photoelectric liquid level sensor has the characteristics of small size, small space, and convenient installation. Compared with the float water level sensor, which is prone to the bad state of the floating ball, the photoelectric water level sensor is highly reliable and has the characteristics of maintenance-free. The photoelectric liquid level sensor is not affected by external factors such as temperature, pressure, magnetism, liquid color, corrosion, etc., and has a wide range of applications. The repetitive accuracy of the photoelectric water level sensor and the accuracy of liquid level control are high, and the scale, etc. will not affect the accuracy of the photoelectric water level sensor. The problem of scale, air bubbles, and water drops hanging on the wall can be handled by software, and the water level sensor is installed because of the structure, and there is no good solution. And only a small part of the area is in contact with the liquid, and there is a separate non-contact structure of the photoelectric water level sensor, so it is more hygienic and in line with food hygiene standards (provided that the sensor head material is food-grade).
The biggest feature of the capacitive water level sensor is that it can be non-contact detection, usually attached to the outer wall of the water tank to detect the water level. Because the capacitive water level sensor does not need to touch the liquid, the corrosiveness of the liquid will not affect the operation of the sensor. It is more hygienic, and can be used in coffee machines, water dispensers and other equipment to detect drinking food liquids. Capacitive water level sensor reliability and accuracy are better than float water level sensor, but not as good as photoelectric water level sensor. The photoelectric water level sensor is very convenient to install, and it can be directly attached to the outer wall of the water tank. The installation process is relatively simple, and the installation process of the float water level sensor is more complicated than that of the capacitive water level sensor.