Mag Meter Conductivity CheckWill a magnetic flow meter work on your fluid?
A magnetic flow meter only works if the liquid conducts electricity. Enter a measured conductivity, or pick a sanitary process fluid, and see how it compares with the published minimums for ifm sanitary and industrial mag meters. Every number is cited. Where no published number exists but the chemistry makes the answer clear, we say “likely” and show the reasoning. Everything else is flagged for measurement, not guessed.
Hygienic Mag Meter
DN15–DN150 (½”–6”), PFA measuring tube, 316L electrodes, clamp or weld adapters. Integrated flow, temperature and conductivity outputs (conductivity reading from 100 µS/cm). SMF150 datasheet
Compact Mag Meter
Threaded process connections for utilities, water and cooling loops. Flow, totalizer and temperature with IO-Link. SM4020 datasheet
Published values describe the sample, concentration and temperature in the cited source. Your product can differ. Conductivity typically rises about 2%/°C for aqueous solutions, so check it at process temperature, not just at the lab bench.
When a mag meter is the right call
- Conductive, water-based liquids: milk, cream, juice, beer, brine and CIP solutions sit in the thousands of µS/cm, far above either minimum.
- Hygienic lines: no moving parts and no obstruction in the flow path, so the meter cleans in place with the line.
- Product and CIP on one meter: the SMF also reports conductivity, which helps tell product, rinse water and cleaning solution apart (from 100 µS/cm up).
- Solids and viscosity: pulp, cultures and thick products don’t wear a mag meter the way they wear mechanical meters. Confirm the flow range for the size you choose.
When to choose something else
- Purified water and WFI: USP water is at or below 1.3 µS/cm at 25 °C, under every mag meter minimum.
- Alcohols, glycerin, oils and solvents: effectively non-conductive.
- Low-mineral waters and high-Brix syrups: they can land near or below the limit. Measure first.
- Alternatives: ifm points non-conductive liquids to its ultrasonic (SU), thermal (SA/SI) and mechatronic (SB) flow families. Ask us which fits your line.
Meter reading wrong? Check these first
- Fluid conductivity: a recipe or water-source change can drop it toward the minimum. Measure at the meter.
- Air and partial fill: the measuring tube must run full. Avoid high points, and keep the meter away from pump suction where air can come out of solution.
- Straight run: the SMF150 datasheet calls for 5×DN upstream and 2×DN downstream.
- Electrode coating and grounding: fat, protein or mineral film on the electrodes and poor grounding both cause unstable readings. Follow ifm’s installation guide for your model.
How to measure your fluid
Take a sample at process temperature, or use an inline conductivity sensor. The SMF’s built-in conductivity output starts at 100 µS/cm, so it can’t confirm a fluid between 5 and 100 µS/cm. For that range, use a separate conductivity sensor such as ifm’s LDL series, or send us a sample description and we’ll help.
For CIP chemicals, ask your chemical supplier for a conductivity-vs-concentration curve for the exact product. Blended cleaners don’t read the same as pure caustic or acid.
Sources
Screening guidance only. Meter minimums are from the cited ifm datasheets and can vary by article; confirm the exact model, size, gaskets and approvals before purchase. Triplex Sales carries the ifm flow and process sensor line.
Not sure about your fluid?
Tell us the product, temperature, line size and flow range. We’ll confirm whether a mag meter fits and size the right ifm meter, or point you to a better technology.
