A magnetostrictive level transmitter is a type of liquid level measurement device that is designed to operate in harsh environments. It uses the principle of magnetostriction to determine the level of a liquid in a container or tank. The device consists of a sensing element, a magnet, and electronic components for signal processing.
Here's how a magnetostrictive level transmitter works:
Sensing Element: The sensing element is typically a flexible metallic wire or rod made of magnetostrictive material, often an alloy such as nickel or iron. Magnetostriction is a property of certain materials that causes them to change their shape when exposed to a magnetic field.
Installation: The magnetostrictive level transmitter is installed in the tank or container with the sensing element extending down to the lowest level of the liquid being measured.
Magnet: A float or sliding magnet is attached to the float chamber or a separate float rod, and it moves freely along the length of the sensing element. The magnet is in direct contact with the liquid being measured.
Measurement Process: When the magnet moves along the sensing element, it creates a magnetic field around the element. The current is applied to the sensing element, producing a magnetostrictive effect in the wire or rod. This effect causes the sensing element to emit a torsional stress wave, which travels at a known velocity along the length of the wire.
Time-of-Flight Principle: The magnetostrictive level transmitter measures the time taken for the torsional stress wave to travel from the point of generation (where the current is applied) to the point where the magnet's magnetic field interacts with the sensing element. The time taken is proportional to the distance between the point of generation and the point of interaction with the magnetic field.
Output Signal: The transmitter's electronic components measure the time-of-flight and convert it into an electrical signal proportional to the liquid level in the tank. This signal is then processed and converted into an output, typically in the form of a 4-20mA signal or a digital signal, representing the liquid level.
Advantages in Harsh Environments:
Magnetostrictive level transmitters are robust and reliable, making them suitable for harsh environments with extreme temperatures, high pressures, or corrosive liquids.
They are non-contact measurement devices, which means there is no physical contact between the sensing element and the liquid being measured. This feature makes them less susceptible to wear and tear and minimizes maintenance requirements.
The absence of moving parts in the sensing element ensures long-term stability and accuracy of measurements.
Magnetostrictive level transmitters can handle a wide range of liquid types, including oils, chemicals, and petrochemicals.
Overall, magnetostrictive level transmitters are an excellent choice for measuring liquid levels in challenging industrial settings where accuracy, durability, and reliability are critical.