The magnetic level gauge is now widely used throughout process industries as an effective level control device.
A magnetic level gauge is often used in applications where a sight glass (or glass sight gauge) is either ill-suited based on process variables or is underperforming based on plant requirements. These can include enhanced safety for personnel; environmentally risky situations including media leakage or fugitive emissions; need for maintenance reduction; or need for high visibility from a distance.
Safety
The obvious safety benefit of the level gauge over a sight glass is reduced chance of breakage. If the process fluid is under extreme pressure or temperature, the likelihood of sight glass breakage is increased. The pressure boundary of an level gauge is made of robust metal, frequently the same as the vessel piping, making level gauge as safe as the surrounding piping system itself. The indicators, transmitters, and switches are all mounted externally and, therefore, are unaffected by toxicity, corrosiveness, or other process fluid characteristics.
Another safety benefit is that the chemical compatibility with the fluid in an level gauge is restricted to only three components, the metallic chamber, gaskets and float. With glass sight gauges, the process fluid may have chemical compatibility issues with any of the wetted materials—glass, metal, or sealants.
Maintenance
Level gauges are virtually maintenance free once installed because the indicator never touches the process fluid. With sight glasses, the gauges must be periodically checked for leaks and cleaned on a regular basis. Scaling, etching and build-up on the glass from the process fluid can cause the sight glass to become unreadable.
Visibility
Visibility of the fluid level from long distances is another major reason for selecting an level gauge over a sight glass gauge. Sight gauge level indicators are intended to be viewed at maximum distances of around 10 feet (3 meters). However, the bright contrasting colors of the flags or a fluorescent shuttle on an level gauge permit visible level indication at distances up to 100 feet (30 meters) or greater.
This article comes from magnetrol edit released