A basic magnetic level sensor, also known as a magnetic float switch or magnetic level indicator, is a simple device used to detect the level of liquid in a container or tank. It relies on the principles of magnetism to function. Here's how it operates:
Components: The magnetic level sensor typically consists of two primary components: a float and a stationary stem or guide tube. The float is a buoyant object that contains a magnet, while the stem is a tube or guide that houses the float and provides a path for the liquid to flow.
Installation: The sensor is installed vertically inside the tank or container, with the guide tube attached to the top of the container and extending down towards the bottom. The float is free to move within the guide tube.
Magnetic Principle: The float inside the guide tube contains a magnet that is oriented in a specific direction, such as vertically. When the liquid level in the tank changes, the float moves up or down along the guide tube.
Level Detection: As the liquid level rises, the float is buoyed upwards, causing the magnet inside to move towards the top of the float. Conversely, when the liquid level drops, the float moves downward, causing the magnet inside to move towards the bottom of the float.
External Switch: At the top or bottom of the guide tube, there is a reed switch or hall-effect sensor, which is a magnetic sensor that can detect the presence of a magnetic field. When the magnet inside the float comes near the reed switch or hall-effect sensor, it triggers the sensor, and the switch changes its state (either opens or closes).
Electrical Signal: The reed switch or hall-effect sensor is connected to an electrical circuit that interprets the state of the switch. When the switch is triggered, it sends an electrical signal to an external control system or an indicator, indicating the liquid level has reached a specific point.
Output: Based on the electrical signal, the control system can activate alarms, display the level on a gauge, or initiate other actions to monitor and control the liquid level in the tank.
The magnetic level sensor is commonly used in various applications, including industrial processes, storage tanks, and liquid level monitoring systems, due to its simplicity, reliability, and low cost.