Microwave Barrier Level Measurement

Microwave Barrier Level Measurement

Microwave barrier level measurement provides non-contact point level detection in solids using a transmitter/receiver “barrier” arrangement across a vessel, chute, or conveyor path. When bulk material interrupts or attenuates the microwave beam, the system switches state to indicate presence/absence at the defined detection line. The method targets discrete detection rather than continuous level, and it is commonly selected for demanding solids environments.

A primary benefit is non-contact operation with essentially no moving parts in the product stream. This supports high reliability in dusty, abrasive, or high-build-up services where mechanical switches can wear or jam. Because detection is based on beam interruption rather than a reflected echo, performance can remain stable even when surface profiles are irregular or when material flow is turbulent.

Design attention is largely geometric. Transmitter and receiver alignment, mounting rigidity, and protection of the microwave windows (from impact, excessive buildup, or thermal cycling) determine long-term stability. The detection point is a line rather than a spot, so the mechanical layout should ensure the beam placement corresponds to the control objective (e.g., “chute plugged” vs. “bin full”) and avoids false trips from stray structures or intermittent product curtains.

Typical applications include plugged-chute detection, conveyor transfer point monitoring, bin inlet verification, and high-level alarms in silos where dust and abrasion are persistent. It is frequently used in mining/minerals, pulp and paper solids handling, and other bulk material systems where equipment availability is tightly linked to early detection of blockages or overfill conditions.

Selection usually considers required span distance, mounting style, environmental rating, and switching speed. For safety functions, installation must ensure the barrier is not easily misaligned or bypassed by material flow patterns. Where maintenance access is limited, adding purge air or protective housings can significantly reduce the probability of window contamination becoming a failure mode.

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