A magnetostrictive level switch is a type of liquid level sensor designed to detect liquid levels in various applications, including hazardous areas. It operates based on the principle of magnetostriction, which involves the generation of mechanical vibrations in a magnetostrictive wire when exposed to a magnetic field.
Here's how a magnetostrictive level switch detects liquid levels in hazardous areas:
Construction: The sensor consists of a magnetostrictive wire, which is typically made of a ferromagnetic material such as nickel or iron. This wire is housed inside a protective tube, usually made of stainless steel or another non-corrosive material, to shield it from the surrounding environment.
Installation in Hazardous Areas: The level switch is designed to meet the safety requirements for hazardous areas, such as those with flammable or explosive atmospheres. It is intrinsically safe and designed to prevent the possibility of ignition.
Magnetic Float: Inside the tube, there is a magnetic float attached to the liquid level indicator or a displacer. This float moves up and down with the liquid level changes.
Electromagnetic Pulse: A current-carrying conductor, usually a coil, is wound around the tube. When a current pulse is sent through this coil, it generates a magnetic field around the magnetostrictive wire.
Interaction with Magnetic Float: As the magnetic field travels along the length of the magnetostrictive wire, it interacts with the magnetic float within the tube. This interaction causes the magnetostrictive wire to generate mechanical vibrations or stress waves.
Time of Flight Measurement: The level switch measures the time it takes for the stress waves to travel from the point of excitation (where the current pulse is applied) to the position of the magnetic float. By knowing the speed at which the stress waves propagate through the wire, the sensor can accurately determine the position of the magnetic float.
Level Indication: The position of the magnetic float corresponds to the liquid level in the tank or container. This data is then converted into an electrical signal that can be used to display the liquid level on a remote indicator, a control system, or trigger alarms and other automation processes.
Hazardous Area Certification: Magnetostrictive level switches designed for hazardous areas are certified by relevant agencies, such as ATEX, IECEx, or CSA, to ensure they meet the safety standards and are suitable for use in potentially explosive atmospheres.
Overall, the magnetostrictive level switch's ability to accurately measure liquid levels in hazardous areas, along with its robust and intrinsically safe construction, makes it a reliable choice for applications where safety and precision are essential considerations.