A basic magnetic level sensor, also known as a float level sensor or magnetic float switch, is a device used to measure the liquid level in a container or tank. It operates based on the principle of buoyancy and magnetic fields. Here's how it works:
Construction: The sensor consists of two main components - a buoyant float and a stationary stem. The float is typically made of a material that is less dense than the liquid being measured, allowing it to float on the liquid's surface. The stationary stem houses the magnetic elements and is attached to the tank's wall or roof.
Magnetic interaction: The float contains a magnetic element, such as a magnet, while the stem also has a magnetic element, either a reed switch or a Hall-effect sensor. A reed switch is a magnetically operated switch that opens or closes when exposed to a magnetic field. On the other hand, a Hall-effect sensor generates an electrical output when a magnetic field is detected.
Positioning: The float is positioned inside the tank, and its movement is determined by the liquid level. As the liquid level changes, the float rises or falls accordingly.
Liquid level measurement: When the float rises or falls, the magnetic element within the float approaches or moves away from the magnetic element within the stem. This proximity or distance affects the magnetic field strength detected by the sensor in the stem.
Signal output: The change in magnetic field strength caused by the movement of the float is detected by the reed switch or Hall-effect sensor in the stationary stem. When the float reaches a certain level (e.g., high or low), the switch or sensor changes state. For example, in the case of a reed switch, it may open or close the circuit.
Electrical connection: The magnetic level sensor is connected to a control system or display unit through electrical wires. The change in state of the reed switch or Hall-effect sensor sends a signal to the control system, indicating the liquid level.
Output interpretation: The control system or display unit interprets the signal received from the magnetic level sensor and displays the liquid level information or performs actions based on the level, such as activating pumps or generating alarms.
Overall, a basic magnetic level sensor is a simple and reliable method for measuring liquid levels in various applications, including industrial processes, storage tanks, and fuel tanks, among others. It is known for its durability, ease of installation, and low maintenance requirements.