A magnetostrictive level sensor is a type of device used to measure the level of liquid in a container or tank. It operates on the principle of magnetostriction, which is the property of certain materials to change their shape in response to the application of a magnetic field. The sensor typically consists of a waveguide and a float.
Here's a step-by-step explanation of how a magnetostrictive level sensor works in liquids:
Waveguide: The waveguide is a long, slender metallic tube made of magnetostrictive material, such as nickel-iron alloy. It is usually installed vertically inside the tank or container, with one end securely mounted at the top.
Float: The float is a cylindrical or rod-shaped device that floats on the liquid's surface. It is attached to the waveguide and can move freely along its length.
Magnetic Pulse Generation: At regular intervals, a magnetic pulse is generated along the waveguide. This pulse is usually created using a coil located outside the tank, which produces a brief burst of magnetic energy.
Propagation of Magnetic Pulse: When the magnetic pulse is generated, it travels down the waveguide at the speed of light. As the pulse passes through the magnetostrictive material of the waveguide, it generates a torsional or longitudinal strain in the material due to the magnetostrictive effect.
Reflection of the Pulse: When the magnetic pulse reaches the float, it encounters a magnetic float assembly. This assembly typically includes a small, cylindrical permanent magnet attached to the float.
Interaction with the Magnetic Float: The magnetic pulse causes a momentary interaction between the magnetic field of the pulse and the magnetic field of the float's permanent magnet. This interaction results in a secondary magnetic pulse being generated in the opposite direction along the waveguide.
Detection of the Secondary Pulse: A sensor located at the top of the waveguide detects the arrival time of the secondary pulse. The sensor can precisely measure the time it takes for the secondary pulse to travel from the float to the sensor. This time delay is proportional to the distance between the float and the sensor, which corresponds to the liquid level in the tank.
Calculation of Liquid Level: The level sensor's electronics process the time delay data and calculate the liquid level based on the known speed of the magnetic pulse in the waveguide and the time taken for the pulse to travel back to the sensor.
Output: The liquid level information is then converted into a suitable output format, such as an analog voltage, current, or digital signal, which can be used for display, control, or further processing by external systems.
Overall, magnetostrictive level sensors provide accurate and reliable level measurements in various liquid applications and are particularly well-suited for continuous level monitoring due to their non-contact measurement principle and minimal maintenance requirements.