Principle of Operation

The Ramsey Granuflow DTR 131 utilize the Doppler Effect. They measure the difference between emitted and reflected microwave frequencies. Their electronics emit a signal that is reflected by moving material. When the material is in motion, the returned signal is either higher or lower in frequency than the transmitted signal. No motion is present if the returned signal is the same frequency as the transmitted signal. Changes in the received microwave energy, due to things such as build-up in front of the antenna, do not affect flow/ no-flow detection. These detectors produce microwave energy at a level of 0.15 mW/cm2 (measured at the antenna horn), which is a much lower level than the international safety standard of 10 mW/cm2. They are certified to FCC-15F.

Typical Equipment Applications

Volumetric Feeders

Detects operational malfunctions, such as blockages, empty hoppers or flushing

Silo Discharge Detects operational malfunctions, such as bridging, rat-holing or loose slide gates

Mechanical Conveyors

Detects damaged conveyors and conveyors running empty Dryers, Screeners, Classifiers, Mills, etc.

Detects proper material flow to and from the process

Pneumatic Conveyors and Injectors

Detects any major operational malfunction

Filters and Cyclones

Detects conditions beyond the equipment's

design parameters

General Specifications

Housing Cast aluminum

Protection DTR 131: NEMA-4 (IP65)

DTR 231: NEMA-4 (IP54)

Ambient Temperature -40°C to +60°C (-40°F to +140°F)

Maximum Temperature

at Sensor Horn Surface +80°C (+175°F)

Weight DTR 131: Approximately 2 kg (4.5 lb)

DTR 231: Transducer: approximately 0.8 kg (1.8 lb); Transmitter: approximately 1.9 kg (4.2 lb)

Maximum Operating Pressure 15 PSI (1 bar)

Power Supply Options 115 VAC or 230 VAC, 50/60 Hz

Power Supply Tolerance 15% - 10%