The coffee machine usually has a water shortage protection function. In the non-transparent water tank, it is impossible to directly check the water level change of the water tank, so the coffee machine usually has a water shortage protection function to prevent dry burning. When there is no water in the water tank, the coffee machine automatically cuts off the power to realize the water shortage protection function or the low liquid level reminding function. When the water level in the water tank drops to the set position, the light alarm or the buzzer alarm prompts the user to add water. .
Similar functions are available in water purifiers, humidifiers, aromatherapy machines, and electric steamers. Both power-off protection and low-level reminders can effectively protect the appliance and prevent the machine from drying. If the water in the steam microwave oven is not available, but the user does not find it, it may cause the food to not be steamed. When the liquid in the humidifier tank is not available, the electrical appliance continues to work, which may cause damage to the electrical appliance, which is very influential to the user experience. Adding the water shortage protection function can protect the electrical equipment and prevent accidents.
The optical fluid sensor can quickly and accurately detect the liquid level in the water tank to realize water shortage protection and low liquid level reminding function. The optical fluid sensor adopts the principle of optical refraction. The internal emission tube emits light, Judging whether the sensor position is in water or no water according to the different light conditions reflected, thereby the level sensor give a different signal. The optical fluid sensor has an accuracy of ±0.5mm. it is maintenance-free. Because there are no mechanical moving parts inside, it has high reliability, it is rarely affected by external factors. Scale, bubbles, water vapor, etc. will not affect the operation of photoelectric level sensor.
The capacitive proximity sensor can also realize the water shortage protection function. The biggest advantage of the capacitive proximity sensor is that non-contact detection can be realized. It is not necessary to open the hole in the container, and the sensor can be attached to the outer wall of the water tank to detect the liquid level. However, the accuracy and reliability are not as good as the optical fluid sensor, and the capacitive liquid level sensor cannot be used on metal containers. The optical fluid sensor can be installed arbitrarily, and can be placed up, down, side, and tilted, while capacitive type is not. The separate photoelectric level sensor can also achieve non-contact detection.