A magnetostrictive level transmitter is a type of level measurement device used to measure the level of liquid in tanks, vessels, or other containers. It operates on the principle of magnetostriction, which is the property of certain materials to change shape in the presence of a magnetic field. The basic components of a magnetostrictive level transmitter include a sensing element, a waveguide, and electronic components for signal processing.
Here's a step-by-step explanation of how a magnetostrictive level transmitter works to measure liquid levels:
Sensing Element: The sensing element of the magnetostrictive level transmitter consists of a magnetostrictive wire made from a material such as nickel, iron, or an alloy. This wire is usually installed within a protective stainless steel tube.
Waveguide: The waveguide is a rigid tube made of non-magnetic material, usually stainless steel, located parallel to the magnetostrictive wire inside the sensing element. The waveguide's purpose is to guide and direct a guided wave generated in the magnetostrictive wire.
Signal Generation: To initiate the level measurement process, a current pulse is sent through the magnetostrictive wire. This current generates a magnetic field around the wire.
Magnetic Field Interaction: When the generated magnetic field interacts with the magnetic field of the float or level probe submerged in the liquid, it causes a torsional stress wave to be generated along the length of the magnetostrictive wire.
Travel Time Measurement: The torsional stress wave travels at a constant speed along the length of the magnetostrictive wire. The transmitter measures the time it takes for this wave to reach the float or level probe and then return to the sensor.
Distance Calculation: By knowing the wave's propagation speed and measuring the time it takes to travel to the float and back, the transmitter can calculate the distance between the sensing element and the liquid level.
Liquid Level Determination: Since the magnetostrictive level transmitter knows the distance from the sensing element to the liquid level, it can determine the liquid level in the tank or vessel accurately.
Output and Display: The transmitter processes the level measurement data and generates an output signal, which can be analog (e.g., 4-20 mA) or digital (e.g., Modbus). This signal can be transmitted to a control system, a display unit, or a data acquisition system for further processing and visualization.
The advantage of using a magnetostrictive level transmitter is its high accuracy and reliability, making it suitable for various industrial applications where precise liquid level measurements are essential.