A magnetostrictive liquid level transmitter is a type of level measurement device used to determine the interface levels in tanks containing two immiscible liquids. It relies on the magnetostrictive principle to accurately measure the liquid levels.
Here's how it works:
Principle of Magnetostriction: Magnetostriction is the property of certain materials to change their shape when subjected to a magnetic field. The magnetostrictive liquid level transmitter contains a magnetostrictive wire, usually made of an alloy, which exhibits this property.
Construction: The transmitter consists of a probe, often inserted into the tank, that extends through both liquids (usually oil and water or other immiscible liquids). The probe typically has multiple sections, each designed to interact with different liquids.
Guided Wave Propagation: The magnetostrictive wire acts as a waveguide. When a brief electrical pulse is sent down the wire, it generates a torsional mechanical wave that travels along the wire at a known velocity.
Wave Reflection: When the wave reaches the interface between the two liquids, it reflects back towards the top of the probe due to the difference in acoustic impedance between the two liquids. The time taken for the wave to travel down the wire, reflect back, and return to the sensor is measured accurately.
Time-of-Flight Measurement: The magnetostrictive transmitter measures the time-of-flight (TOF) of the wave. By knowing the velocity of the wave in the wire, which remains constant, and the TOF, the transmitter can determine the distance from the top of the probe to the interface between the two liquids.
Calculation of Interface Level: Once the distance to the interface is known, the level of the upper liquid (e.g., oil) can be calculated by subtracting the distance from the top of the probe to the interface from the total tank level. Similarly, the level of the lower liquid (e.g., water) can be calculated by subtracting the interface distance from the bottom of the probe.
Output: The magnetostrictive liquid level transmitter converts the measured distances into an electronic signal (e.g., 4-20mA) that can be displayed or further processed by a control system or a remote monitoring device.
The magnetostrictive liquid level transmitter is known for its accuracy, reliability, and ability to measure interface levels in tanks with a high level of precision. However, it's important to ensure the probe is appropriately designed for the specific application to achieve accurate and reliable measurements.