A magnetostrictive level sensor is a type of liquid level measurement device that relies on the principle of magnetostriction to determine the level of a liquid in a container. Magnetostriction is the property of certain materials to change their shape or dimensions when exposed to a magnetic field. This property is utilized in magnetostrictive level sensors to accurately measure liquid levels.
The working principle of a magnetostrictive level sensor involves the following components:
Waveguide Tube: The sensor consists of a waveguide tube made of a non-magnetic, corrosion-resistant material. This tube is installed vertically in the tank or container where the liquid level needs to be measured. It is usually mounted along the tank's side, extending from the top to the bottom.
Magnetostrictive Wire: Inside the waveguide tube, there is a magnetostrictive wire made of a ferromagnetic material, such as nickel or iron. This wire is highly sensitive to changes in magnetic fields and has the property of magnetostriction.
Electronics and Transducer: At the top of the waveguide tube, there are electronic components and a transducer assembly. The transducer generates a low-energy electrical pulse, which travels down the magnetostrictive wire.
Float: A buoyant float, often made of a magnetic material, is attached to the wire and floats on the liquid surface. The float moves up and down with the liquid level changes.
Here's how the magnetostrictive level sensor works:
Pulse Generation: The electronic circuit sends an electrical pulse through the magnetostrictive wire. This pulse creates a magnetic field along the entire length of the wire.
Magnetic Field Interaction: When the electrical pulse reaches the float, it encounters the magnetic field of the float, which results in a torsional stress wave being generated in the magnetostrictive wire. The location of this torsional wave corresponds to the position of the float along the waveguide tube.
Time-of-Flight Measurement: The sensor's electronics measure the time it takes for the torsional wave to travel back to the top of the waveguide tube. This time-of-flight measurement is precisely recorded.
Calculation of Liquid Level: Using the known speed of the torsional wave propagation in the magnetostrictive wire, the electronic circuit calculates the distance between the transducer and the float. This distance represents the liquid level in the tank.
Output Display: The calculated liquid level is then displayed on a connected control panel, HMI (Human-Machine Interface), or any other output device.
The process of generating and detecting the torsional wave is repeated at regular intervals to continuously monitor the liquid level. As the liquid level changes, the position of the float also changes, and the sensor provides real-time and accurate level measurements.
Magnetostrictive level sensors are commonly used in various industrial applications, including storage tanks, chemical processing, water treatment, and oil and gas industries, where precise and reliable liquid level measurements are essential.