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Magnetic Flow Sensors and Electromagnetic Flow Transmitters: High Performance Field Instruments
Quick Answer: Magnetic flow sensors and electromagnetic flow transmitters from Silver Instruments measure conductive liquids from 0.1 m/s to 12 m/s in line sizes from DN10 to DN2000. Accuracy reaches 0.2 percent of reading with 4-20 mA HART, pulse, and RS485 Modbus outputs. Send your fluid type, conductivity in µS/cm, pressure in bar, temperature in °C, pipe size in DN, and flow range for a quote.
This guide covers what engineers and buyers need to know before selecting a magnetic flow sensor or an electromagnetic flow transmitter for water, chemical, food, mining, or desalination service. Silver Instruments supplies these field instruments to Southeast Asia, Oceania, Latin America, Africa, and the Middle East.
Sensor vs Transmitter in One Field Instrument
A magnetic flow sensor includes the flow tube, excitation coils, and electrodes. The transmitter reads the microvolt signal from the electrodes and converts it into a usable output. Some projects use a remote transmitter. Compact types are common for small skids and tight pump rooms. Remote types suit flooded pits, hot pipes, and high vibration areas. Silver Instruments builds both versions with the same accuracy spec.
In practice, most engineers skip the separate sensor discussion and ask for a complete electromagnetic flow transmitter. The transmitter is the field instrument that shows flow rate, total flow, and diagnostics. Standard outputs are 4-20 mA HART, pulse, frequency, and RS485 Modbus RTU.
Specifications That Matter for Field Installations
Line size drives many choices. A DN15 electromagnetic flow transmitter handles small chemical dosing lines. A DN400 unit handles plant effluent. A DN2000 unit handles raw water intake at a desalination plant. Silver Instruments can supply sizes from DN3 up to DN2000. Accuracy is 0.2 percent of reading for DN25 and larger lines. Smaller lines usually have 0.5 percent accuracy. Minimum fluid conductivity is 5 µS/cm for standard water applications. Special low conductivity designs can measure down to 0.05 µS/cm.
Liner materials include PTFE, PFA, hard rubber, and polyurethane. Electrode materials include 316L stainless steel, Hastelloy C, titanium, tantalum, and platinum. Process connections include wafer, flanged, sanitary tri-clamp, and threaded types. A PT100 temperature sensor can be added to the same process line if temperature logging is needed. Protection ratings are IP67 for standard units and IP68 for submerged installations. ATEX Zone 1 and IECEx hazardous area versions are available for oil and gas or solvent service.
Where These Flow Meters Work Best
Water and wastewater plants use them for raw water, treated water, sludge, and return activated sludge. A wastewater utility in Vietnam installed a DN200 electromagnetic flow transmitter with hard rubber liner and 316L electrodes on a return sludge line. The unit has run with 0.3 percent repeatability for more than four years.
Desalination plants use magnetic flow sensors on seawater feed, brine reject, and permeate lines. For seawater feed, choose PTFE liner and titanium or Hastelloy C electrodes. A desalination contractor in Australia ordered 14 DN150 units with 4-20 mA HART output for a seawater reverse osmosis plant. The delivery included IP68 remote transmitters for outdoor pipe galleries.
Food and beverage plants use sanitary electromagnetic flow transmitters for milk, beer, syrups, and liquid chocolate. A beverage factory in Thailand uses DN15 and DN25 sanitary units with PFA liner and 316L electrodes for syrup dosing. Chemical plants use PTFE lined meters for acids and caustic. Mining sites use polyurethane liners for abrasive slurry. So the fluid and pipe material decide the right model.