The Disadvantages Of Float Level Switch And Electric-optic Level Switch

- Jul 02, 2019-

The disadvantages of vertical float switch


1. The float is easy to get stuck and does not move. The float float type liquid level switch pushes the float of the magnet up and down by the buoyancy of the liquid, so that the internal reed switch is opened and closed,  the minimum liquid level will be greatly limited. 


2. The float level sensor has a limited environment, such as a highly viscous liquid, a liquid with impuritie, and corrosive liquid. Viscous liquids and impurities will cause the float to become stuck and inoperable, while corrosive liquids, some float-type liquid level sensors like plastic material level switchs can not be used.


3. The liquid level float switch can only be installed on the upper or lower side, and the fixed installation method limits the product. But there are many electrical appliances, the tanks are irregularly shaped.


4. The level switch float type detects the liquid level by the float up and down according to the change of the liquid level, and the operation is simple, so the detection precision is low, and the liquid level control precision can only be controlled at ±3 mm or even higher.


5. The magnetic float level switch has a loose structure and is not easy to clean. The magnet will adsorb impurities in the water and cause scale.


The disadvantages of optical liquid level sensor


  1.  The photoelectric liquid level sensor cannot be used under direct sunlight, and the photoelectric liquid level sensor detects the liquid level according to the reflection principle of infrared light. The sun contains infrared light, which interferes with the detection of the photoelectric level sensor.


2. Optical water level sensor will cause misjudgment of the sensor if the water drops covers on the surface of liquid level sensor (water vapor), or if the liquid level fluctuates frequently. For example, if the container is moving, the liquid level in the container will fluctuate as the machine and equipment move.


How avoid these disadvantages of float ball level switch?


Because of design structure and working principle of float tank level sensor switch, this type sensor exist many unavoidable shortcomgs, such as limitation of minimum liquid level, difficulty in cleaning, and scale generation. The only thing that can be done is to eliminate some unsuitable environments according to  these shortcomings of the float type.


How avoid these disadvantages of photo-electric level switch?


1) The misjudgment due to direct sunlight. It can be avoided by means of a probe facing down, or by using a hood.


2) The misjudgment due to steam, bubble etc. This factor can be taken into account in the program to avoid false positives caused by water drops.


3) The misjudgment due to fluctuates. The ability to add anti-shake logic to the program to solve the impact of liquid level fluctuations.