Conductive Level Measurement

Conductive Level Measurement

Conductive level measurement is designed for point level detection in conductive liquids. It operates by using electrodes that rely on the liquid’s ability to conduct electricity: when the liquid reaches the sensing point, it completes an electrical path and the instrument switches state. The approach is inherently discrete (alarm/control points rather than continuous indication) and is commonly applied where the process liquid’s conductivity is reliably above a minimum threshold.

Benefits center on clarity and simplicity. The switching behavior directly represents “wet” versus “dry” at the electrode location, which makes it attractive for straightforward pump control, high-high alarms, and interlocks. The method is typically tolerant of headspace vapors and is not dependent on echo quality or line-of-sight geometry, so it can be applied in small vessels or tight pipework where non-contact methods are difficult to implement.

The essential constraint is application fit: conductivity must be sufficient and stable across temperature and concentration ranges. Non-conductive products (many hydrocarbons, solvents, and deionized liquids) are poor candidates. Design should also consider electrode coating, scaling, or corrosion; these can change the effective conduction path and lead to delayed switching or nuisance trips if materials of construction and cleaning practices are not aligned with the service.

Typical applications include water and wastewater lift stations, sumps, basins, and tanks; food and beverage utilities and cleaning systems; and chemical processes involving aqueous solutions, brines, and many slurries. It is often selected for level control in smaller tanks where one or more fixed switch points are sufficient, and where a simple relay output to a pump starter or PLC input is the primary requirement.

Practical selection focuses on the number of switch points, mounting orientation, hygienic or industrial process connections, and electrode materials compatible with both chemistry and cleaning. Where process safety is involved, the switching logic (fail-safe high/low) and diagnostic coverage should be evaluated so the instrument’s failure behavior supports the intended protective function rather than undermining it.

George E. Booth Co., an exclusive authorized representative of sales and service for Endress+Hauser.