A magnetostrictive liquid level sensor is a device used to measure the level of a liquid within a container or tank. It operates on the principle of magnetostriction, which is the phenomenon where certain materials change their shape in response to an applied magnetic field. This property is used to accurately determine the position of a magnetic float or probe within a liquid.
The basic working principle of a magnetostrictive liquid level sensor involves the following components:
Probe Tube: This is a hollow tube made of a magnetostrictive material, typically a nickel-based alloy. The probe is installed vertically within the tank, with one end extending to the bottom and the other end extending above the highest liquid level.
Float: A magnetic float is attached to the liquid surface. This float is buoyant and moves up and down with the changing liquid level. The float usually contains a magnet or a magnetic element.
Electronics Module: The probe tube contains an electrical conductor, which acts as a waveguide for electromagnetic pulses. The electronics module generates these pulses and sends them down the probe tube. This module also measures the time it takes for the pulses to travel back to the surface after being reflected at the float.
Here's how the sensor works:
Pulse Generation: The electronics module sends a short electromagnetic pulse down the probe tube's conductor.
Pulse Reflection: When the pulse reaches the interface between the magnetostrictive probe and the liquid, it is partially reflected back towards the surface.
Float Detection: The pulse travels at a known speed through the probe tube, and the electronics module measures the time delay between pulse transmission and its reception after reflection. When the pulse encounters the magnetic float, it induces a mechanical strain in the magnetostrictive material due to the float's magnetic field. This strain generates a mechanical wave that travels back towards the top of the probe.
Time Measurement: The electronics module precisely measures the time it takes for the mechanical wave to travel from the float back to the top of the probe. This time delay is directly proportional to the distance between the top of the probe and the liquid surface, which corresponds to the liquid level in the tank.
Calculation: Using the known speed of the pulse in the probe material and the measured time delay, the electronics module calculates the liquid level in the tank. The output can be displayed on a digital readout, transmitted to a control system, or used for other relevant applications.
Magnetostrictive liquid level sensors are known for their high accuracy, repeatability, and reliability. They are commonly used in various industries, including oil and gas, chemical processing, water treatment, and more, where precise and consistent liquid level measurement is essential for efficient operation and safety.