The Thermo Scientific Ramsey Granuflow
DTR 131 and DTR 231 are low-cost, noninvasive, microwave-based instruments that detect and monitor flow/no-flow conditions of bulk solids in pipelines, ducts and air-slides, as well as at transfer points of chutes, conveyor belts and bucket elevators. Used for automation purposes, they efficiently optimize the use of machinery and energy by switching process equipment on or off as required. The RamseyTM Granuflow DTR 131 and DTR 231 have no moving mechanical parts, which eliminates wear and makes the instruments maintenance-free and trouble-free.
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%
Operating Frequency (microwaves) 24.124 GHz
Detection Range 0 m - 1.5 m (0 ft - 5 ft) depending on application
Relay Output/Contact Rating Max. 250 V; Max. 4 A; Max. 500 VA (AC); Max. 100 W (DC)
Switching Delay On or Off delay (selectable); Switching delay adjustable between one and ten seconds
Transducer Mounting Special slotted aluminum flange mates with standard 1.5 in 150 lb ANSI flange
Approvals/Certification Dust-ignition-proof Class II, Div. 1, Groups E-G, for outdoor locations; Certified to FCC-15F;
Model DTR 131 FM approved and CSA approved for non-hazardous areas
Options HF-permeable window with flange to maximum pressure of 150 PSI;
Maximum temperature of +288°C (+550°F); Mounting bracket with window or standalone;
Pipe standoff with mounting flange (45° or 90°)
Manufacturing Quality ISO-9001 Certified
Note: For vessel wall temperatures exceeding +60°C (+140°F), contact factory for planning instructions.
