A basic magnetic level sensor is a type of liquid level measurement device that utilizes the principles of magnetism to determine the level of a liquid in a container or tank. It consists of three primary components: a float, a magnetic system, and a sensing element.
Float: The float is a buoyant object, often cylindrical or oblong in shape, which is placed inside the liquid whose level needs to be measured. The float is free to move up and down with the liquid level changes.
Magnetic System: The magnetic system typically consists of a permanent magnet that is either located inside the float or attached to it. The magnet creates a magnetic field around it.
Sensing Element: The sensing element is mounted outside the container or tank and is usually fixed to its sidewall. It contains a magnetic sensor, such as a reed switch or Hall-effect sensor, capable of detecting changes in the magnetic field.
Operation:
When the tank is empty or the liquid level is below the sensor's range, the float rests at the bottom of the container, and the magnetic field from the magnet does not strongly influence the magnetic sensor on the outside.
As the liquid level rises, the float also rises, bringing the magnet closer to the sensing element. When the magnetic field strength reaches a certain threshold, the magnetic sensor is activated, indicating the presence of the magnet. This activation signal is transmitted to the control system or display unit, which can then interpret the signal to determine the liquid level.
Conversely, as the liquid level decreases, the float descends, moving the magnet farther away from the sensing element. Once the magnetic field strength drops below the threshold, the magnetic sensor is deactivated, indicating a lower level.
Advantages of Magnetic Level Sensors:
Simplicity: Magnetic level sensors are relatively simple in design and operation, making them reliable and easy to maintain.
Non-contact Measurement: They provide non-contact level measurement, minimizing the chances of contamination or interference with the liquid being measured.
Wide Application: These sensors can be used for various liquids, including corrosive and hazardous substances.
High Reliability: Due to their lack of moving parts and non-contact operation, they are generally reliable and have a long service life.
However, it is essential to consider factors such as the liquid's specific properties and the tank's construction material to ensure the proper functioning and accuracy of the magnetic level sensor.