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Quick Answer: An electromagnetic flow meter measures conductive liquid flow with Faraday law of induction. It has no moving parts and no obstructions in the pipe. For water, wastewater, acids, slurries, and food products, Silver Instruments supplies magnetic flow meters from DN15 to DN2000 with 4-20 mA HART output.
This page explains how the electromagnetic flow meter working principle fits non-moving part metrology frameworks. It also covers material selection, installation, and ordering details for industrial buyers.
A magnetic flow meter creates a magnetic field across the pipe. Conductive liquid flows through this field. Electrodes on the pipe wall measure voltage. Voltage is proportional to flow velocity. The transmitter converts voltage into flow rate. No moving parts touch the liquid.
Faraday law governs this measurement. The voltage equals magnetic flux density times conductor length times velocity. In a magmeter, conductor length is the pipe diameter. The transmitter handles the math.
Oval gear meters and turbine meters need bearings, gears, or rotors. Those parts wear in dirty water or slurry. Magnetic flow meters have no rotor, no gear, no bearing. The pipe remains open. Pressure drop is almost zero. This is a real advantage for wastewater lift stations and chemical dosing lines.
We have seen a customer in Vietnam replace turbine meters on a starch slurry line every 6 months. After switching to a DN80 electromagnetic flow meter with PTFE liner, the meter ran for 3 years without service.
Electromagnetic flow meters have three main parts. The sensor body, the electrodes, and the transmitter. The liner isolates the fluid from the metal body. Common liners are PTFE, PFA, hard rubber, and EPDM. Electrodes can be 316L stainless steel, Hastelloy C, titanium, or tantalum.
For drinking water, EPDM liner and 316L electrodes are enough. For sulfuric acid, choose PTFE or PFA liner with tantalum electrodes. For abrasive slurry, polyurethane liner works better. Silver Instruments helps you match materials to your fluid.
Magnetic flow meters require a minimum electrical conductivity. Most standard models need at least 5 µS/cm. Demineralized water and pure hydrocarbons cannot be measured with this technology. Most water, wastewater, acids, caustic, and food liquids exceed this limit easily.
Sizing matters more than accuracy specs. A magnetic flow meter works best between 0.5 and 10 meters per second flow velocity. Too low velocity reduces accuracy. Too high velocity accelerates liner wear. Send us your pipe size in DN and normal flow range in cubic meters per hour. We will check velocity for you.
Install the sensor in a full pipe. Avoid mounting at the highest point where air collects. Provide straight pipe runs before and after the meter. Usually 5 diameters upstream and 3 diameters downstream is enough. Keep the meter away from strong electromagnetic interference from large motors or variable frequency drives.
Here is the thing. Most installation errors come from air pockets or poor grounding. The sensor needs a good earth connection. For metal pipes, ground rings or grounding electrodes may be needed. For plastic pipes, use a grounding ring or built-in grounding electrode. We ship most magmeters with grounding rings when the process needs them.
Silver Instruments electromagnetic flow meters support 4-20 mA output with HART. Pulse output and RS485 Modbus are optional. This fits most PLC, DCS, and SCADA systems. A 4-20 mA signal can run up to 1000 meters with proper cable and shielding.
For batching and custody transfer, choose pulse output. For remote monitoring in water networks, RS485 Modbus is practical. One customer in the Philippines uses Modbus to monitor 12 groundwater wells from a central station.
We supply magnetic flow meters to water treatment plants in Indonesia, mining sites in Western Australia, food factories in Brazil, and chemical plants in Saudi Arabia. The non-moving part design handles raw sewage, sludge, brine, fruit pulp, and corrosive acids.
Typical applications include raw water intake, filter backwash, chemical dosing, cooling water, and effluent discharge. For desalination plants in the Middle East, we supply seawater flow meters with duplex stainless steel electrodes and PTFE liners. Because there is no obstruction, the meter does not catch solids or fibers. This is useful in palm oil mills in Southeast Asia where fibrous solids often clog other meter types.
Send us your pipe size (DN), fluid type, conductivity (µS/cm), operating pressure (bar), temperature (°C), and flow range (m³/h). We will recommend a liner and electrode combination. You will receive a technical offer with price and delivery time.
Contact Silver Automation Instruments today. Tel: +86-25-68650347. WhatsApp: +86-25-52155837. WeChat: +86 15365082610.
What liquids can an electromagnetic flow meter measure?
It measures conductive liquids such as water, wastewater, acids, caustic, slurries, and food products. The fluid conductivity should be above 5 µS/cm for standard models.
Does a magnetic flow meter work on non-conductive oil?
No. Crude oil, diesel, and gasoline are non-conductive. Use a Coriolis or oval gear flow meter for these fluids.
What is the accuracy of a Silver Instruments electromagnetic flow meter?
Standard accuracy is 0.5 percent of reading for velocities above 0.5 m/s. Optional 0.2 percent of reading is available for custody transfer.
Can I install a magnetic flow meter vertically?
Yes. Vertical installation with upward flow keeps the pipe full and reduces air bubble problems. Avoid downward flow in open discharge lines.
How long does delivery take?
Standard DN15 to DN300 meters ship in 5 to 10 working days from our factory in China. Larger sizes up to DN2000 may take 3 to 4 weeks.
