The simplest method for level control is to use a float switch magnetic, which operates on a simple principle. It uses the water level to rise and fall to drive the float. The magnet inside the float will also rise and fall. During the rise and fall process, the magnet will drive the reed switch to open and close, thereby controlling the liquid level.
The float switch magnetic is easily affected by water level and other factors, its accuracy and reliability are low. After using for a period of time, it is easy to cause the floating ball to be stuck and cause bad phenomena. In addition, the floating ball type has the disadvantages of large volume, large space required for installation, complicated installation technology, and loose structure that is not easy to clean.
So if you want to replace the float switch magnetic, which level sensor is more reliable?
The simplest way is to use a capacitive level switch, which can be directly attached to the outer wall of the water tank to work, and is easy to install. Capacitive liquid level sensors have higher reliability and accuracy than floating ball liquid level sensors, but they are not as good as photoelectric liquid level sensors. In addition, the capacitive liquid level sensor has restrictions on the water tank. The thickness of the water tank wall cannot exceed 4mm, it cannot be used on metal containers, and it cannot detect hot water.
The optical level switch is the most suitable. The optical level switch has the characteristics of high reliability, high accuracy, small size and long life. After the liquid level sensor is installed, it can be used without commissioning. To install the sensor, you need to open a hole of about 11 ~ 14mm in the water tank and screw it in directly or fix it with screws. The separate photoelectric liquid level sensor is non-contact detection, so there is no need to open the water tank.
The optical level switch judges whether there is liquid or no liquid at this position according to the reflection of light in two media. The two media are air and liquid. When the sensor head is exposed to the air, the light is directly reflected back to the receiver of the sensor. When the sensor head is immersed in the liquid, light will be refracted in the liquid, and only a little or no light will be reflected back to the receiver. The sensor judges to output different voltage signals according to these two states. After receiving the signal, the device controls the liquid level. For example, the pump starts to add water when the water is lower than the sensor head, and the pump stops adding water when the water is higher than the sensor head.
Because the optical level switch uses the principle of optical reflection to work, the liquid density, color, temperature, pressure, corrosiveness, small impurities in the liquid and scale will not affect the sensor's work, and the stability is strong. In terms of installation process, reliability and accuracy, the photoelectric liquid level sensor is completely better than the floating ball type liquid level sensor.