A basic magnetic level sensor is a device used to measure the level of liquid within a container or tank using the principles of magnetism. It consists of a float, which contains a magnet, and a stationary sensor unit positioned outside the container. The float moves up and down with the liquid level, and the sensor unit detects the position of the magnet to determine the liquid level. Here's how it operates:
Components: The sensor consists of two main components: the float and the sensor unit. The float is a buoyant object designed to move up and down with the changing liquid level. It houses a permanent magnet. The sensor unit is positioned externally to the container and contains a magnetic sensor or reed switch.
Installation: The float is typically attached to the container's interior by a guide or rod, allowing it to move freely within the liquid. The sensor unit is mounted externally at a height corresponding to the desired level measurement point.
Principle of Operation:
Low Level: When the liquid level is low, the float rests at the bottom of the container, and the magnet is positioned near the bottom of the float.
Rising Level: As the liquid level increases, the float begins to rise. The magnet inside the float also moves upward.
Detection: When the magnet inside the float reaches a certain proximity to the sensor unit, it triggers the magnetic sensor or reed switch. The reed switch is a simple switch that is activated by the presence of a magnetic field.
Output Signal: The activation of the reed switch generates an electrical signal, indicating that the liquid level has reached a specific point. This signal can be used to trigger alarms, control pumps or valves, or provide level readings to monitoring systems.
Advantages:
Simple and reliable technology.
Minimal contact with the liquid, reducing the risk of contamination or corrosion.
Suitable for a wide range of liquids, including corrosive or hazardous substances.
Limitations:
Limited to point-level measurements; it provides information only when the float reaches the sensor.
Susceptible to false readings due to factors like turbulence, splashing, or external magnetic fields.
Not suitable for continuous level measurement or applications where very precise measurements are required.
In summary, a basic magnetic level sensor uses a float with a magnet and a sensor unit with a reed switch to detect the liquid level in a container. The position of the float's magnet triggers the sensor, generating an electrical signal that can be used for various control and monitoring purposes.