Radiometric Level Measurement

Radiometric Level Measurement

Radiometric level measurement supports continuous level measurement and point level detection in liquids and bulk solids using gamma-based devices. A radioactive source and detector are mounted externally; as the process level changes, gamma attenuation through the vessel changes, and that signal is converted to level (or sometimes density/interface) without contacting the product. This is typically reserved for applications where other technologies cannot operate reliably due to extreme conditions or mechanical constraints.

The primary advantage is that it is completely external and largely immune to process extremes - high pressure, high temperature, corrosive media, severe buildup, or abrasive solids - because nothing is inserted into the vessel. Thick-walled vessels, lined reactors, or vessels with internal obstructions that defeat radar echoes can still be measured radiometrically. Reliability can be very high once the geometry is engineered and the system is properly commissioned.

Constraints are primarily regulatory and procedural rather than process-physics. Possessing and operating radioactive sources requires licensing, controlled handling, and documented safety practices. Shielding design, access control, and lifecycle management of the source are part of the engineering scope. While the measurement hardware may be low-maintenance, organizational readiness and compliance overhead must be included in total cost of ownership.

Radiometric level is commonly applied in chemical and petrochemical reactors, separators, and columns; mining and minerals slurries and solids vessels; and power/energy processes where heat, pressure, or coatings render contact or non-contact alternatives unstable. It is also used for point detection in critical high-level interlocks when conventional switches cannot survive the service.

Selection involves source strength, detector technology, mounting geometry, and required response time/accuracy. Engineering work includes verifying beam paths through the vessel, evaluating background radiation influences, and defining setpoints and diagnostics that fit the process risk profile. When implemented for safety functions, the management system around licensing, inspections, and proof testing is as important as the measurement itself.

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