A basic magnetic level sensor is a device used to measure the level of liquid in a container or tank. It operates on the principle of magnetism and utilizes a float with an embedded magnet to detect the fluid level. Here's how it works:
Construction: The magnetic level sensor typically consists of two main components: a stationary guide tube and a magnetic float. The guide tube is installed vertically inside the container or tank, while the magnetic float is designed to move freely within the guide tube.
Magnetic Float: The float is a hollow, buoyant object that is sealed and filled with air. It is made from a material that is resistant to the fluid being measured, ensuring it does not absorb the liquid or become heavier over time.
Magnet Inside the Float: The magnetic float contains a permanent magnet or a magnetic element, usually situated in the float's center or near the top. This magnet interacts with the sensor components outside the guide tube.
Sensor Assembly: Mounted externally around the guide tube are one or more reed switches or Hall effect sensors. Reed switches consist of two metal reeds that are enclosed in a hermetically sealed glass tube containing inert gas. Hall effect sensors, on the other hand, rely on the principle that when a magnetic field is present, a voltage difference is generated across a conductor.
Fluid Level Detection: As the liquid level inside the tank rises or falls, the magnetic float moves up or down within the guide tube. When the float reaches a certain level, the magnet inside aligns with one of the sensors mounted outside the guide tube.
Sensor Response: When the magnet in the float aligns with a reed switch, the switch closes, completing a circuit and sending an electrical signal to the external monitoring system. Similarly, with Hall effect sensors, the presence of the magnetic field causes a change in voltage output, which is detected by the external system.
Output Signal: The electrical signal generated by the sensor is then transmitted to a level indicator, controller, or other monitoring devices. These systems can display the current level, trigger alarms, or perform automated actions based on the measured level.
Overall, the magnetic level sensor provides a simple and reliable method for measuring fluid levels in various industrial and commercial applications. It is commonly used in liquid storage tanks, chemical processing plants, water treatment facilities, and other situations where accurate level monitoring is essential.