Guided Radar Level Measurement

Guided Radar Level Measurement

Guided Radar Level measurement (guided wave radar) transmits microwave pulses along a probe (rod, cable, or coaxial waveguide) and evaluates reflections from the product surface and, when applicable, from interfaces between layers. Because the energy is guided, the method delivers continuous level measurement in liquids and solids with strong immunity to many vessel and vapor-space effects. It is particularly effective where a defined measurement path is preferred.

Core benefits include high accuracy and repeatability across wide pressure and temperature ranges, with low sensitivity to vapor, density changes, and many process transients. Guided radar performs well in narrow vessels, bypass chambers, and stilling wells, and it is often chosen where foam, turbulence, or internal structures challenge free-space techniques. Interface measurement in liquid-liquid services is a differentiator when dielectric contrast supports a distinct second reflection.

The main engineering constraints are related to probe selection and interaction with the process. Very low dielectric media may require coaxial probes or specialized designs to ensure a strong reflection, and heavy buildup on the probe can influence performance if not mitigated through coating strategy, compensation, or cleaning. In solids, mechanical loading and abrasion demand robust cable/rod designs and careful placement to avoid bending forces or contact with internals.

Applications span chemical storage, separators, reactors, and vessels with confined nozzles or complex internals, as well as solids silos where dust and vapor conditions are variable. Guided radar is commonly applied to measure interfaces in oil/water separation, product/water bottoms in tanks, and layering in process vessels, provided the interface is sufficiently stable and reflective. It also supports reliable measurement in high-pressure and high-temperature services where mechanical methods are less attractive.

System integration typically uses 2‑wire 4–20 mA with digital overlays and/or fieldbus communications, enabling echo-curve analysis, remote commissioning, and advanced diagnostics. Robust specification focuses on probe geometry, mounting, and dielectric requirements, plus ensuring that the probe remains mechanically stable across operating conditions. Where required, functional-safety configurations support overfill prevention and critical interlocks with clear proof-testing strategies.

Miller Mechanical Specialties, an exclusive authorized representative of sales and service for Endress+Hauser.