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『Rosemount Mag Flow Meter: Sizing 8700 Series Electromagnetic Probes』Related information(flow rotameter|digital flow meter|balo meter|hydraulic flow meter|volumetric meter|positive displacement meter|pitot tube flow meter|displacement meter|cfm meter|variable area flow meter|inline flow meter|differential pressure flow meter|calibrated flow meter|velocity meter|paddle wheel flow meter|oval gear flow meter|anemometer hvac|multiphase flow meter|doppler flow meter|thorpe tube flowmeter|heat flow meter)
Rosemount Mag Flow Meter: Sizing 8700 Series Electromagnetic Probes
Quick Answer: Sizing an 8700 series electromagnetic flow probe starts with the exact inside diameter of your pipe. Match the sensor DN to the pipe DN to keep flow velocity between 0.3 and 10 m/s. Silver Instruments cross references 8700 dimensions and liner materials for direct compatibility and offers faster delivery to Southeast Asia, Latin America, and the Middle East.
Why Correct Probe Sizing Affects Accuracy and Lifetime
Rosemount 8700 probes measure volumetric flow using Faraday law of induction. The coils inside the spool generate a magnetic field. The electrodes pick up the voltage. If the sensor diameter is too small, the fluid velocity exceeds the recommended 10 m/s limit. High velocity wears the liner and the electrodes faster. We have seen a water utility in Vietnam replace an undersized DN80 8700 sensor three times in two years because the velocity always stayed above 12 m/s.
If the sensor diameter is too large, the velocity drops below 0.3 m/s. The signal becomes weak. The transmitter may struggle to filter 50 Hz noise. This causes unstable readings. A chemical plant in Thailand contacted us about a DN300 mag meter that read zero flow during low batch rates. The root cause was an oversized 8700 probe running at 0.2 m/s. Silver Instruments recommended a DN150 sensor with a concentric reducer. They gained stable 4-20 mA output right away.
Key Parameters You Need Before Sizing an 8700 Probe
Always have these values ready: pipe schedule, actual inside diameter in mm, fluid conductivity (must be above 5 µS/cm for 8700), maximum operating temperature and pressure, liner material compatibility, and electrode material. Most engineers skip the conductivity check for demineralized water. But demin water often drops below 1 µS/cm. A power plant in Indonesia learned this the hard way. Their 8700 probe output jumped randomly. Silver Instruments helped them switch to a magnetic flowmeter with a high impedance preamplifier for low conductivity.
For seawater or brine above 50 µS/cm, standard Hastelloy C electrodes work well. For acids, use Pt-Ir electrodes and PTFE liners. Rosemount 8700 sensors use PFA liners up to 180 deg C. If your process runs at 150 deg C consistently, PFA is fine. Silver Instruments offers PFA liners for DN15 to DN600 as standard on our MFE series.
Cross Referencing 8700 Probes with Silver Instruments Mag Meters
Many users ask us: can I drop a Silver mag meter into an existing Rosemount 8700 installation? The short answer: yes, often you can. Our sensor flange standards match EN 1092-1 and ASME B16.5. Spool lengths fol
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The transmitter wiring stays the same when you order 4-20 mA HART output and pulse. Silver Instruments also supplies Profibus PA and Modbus RTU. We encourage you to send photos of your existing 8700 nameplate and the pipe inside diameter to [email protected]. We will reply with a 1 to 1 compatibility chart within 24 hours.
FAQ
What are the liner options for 8700 series probes?
Rosemount offers PTFE, PFA, hard rubber, and soft rubber liners. Silver Instruments uses PFA as default for chemical resistance up to 180 deg C and natural rubber for seawater. Ask us about EPDM for drinking water with WRAS approval.
Can I use an 8700 probe for slurry?
Yes, with a soft rubber liner and tungsten carbide electrodes. The minimum velocity must stay above 1.5 m/s to prevent settling. Silver Instruments supplies ceramic lined mag meters for abrasive mining slurries up to 60% solids.
How long is the straight pipe requirement for 8700 sensors?
Rosemount specs recommend 5 pipe diameters upstream and 2 pipe diameters downstream from the probe. Silver Instruments repeats the same requirement in our installation manuals. If you have less space, consult us. We have a DN100 inline flow conditioner that reduces the upstream need to 3D.
What is the maximum pressure rating?
Standard 8700 sensors handle up to PN40. Some versions go to PN100. Silver Instruments builds high pressure mag meters up to PN160 with welded construction. Share your pressure (bar) and we will propose the right flange class.
What is the typical delivery time for replacement probes?
Rosemount lead times can stretch to 8 to 10 weeks in some regions. Silver Instruments stocks sensors from DN25 to DN200 in China and dispatches within 1 to 2 weeks. Larger sizes ship in 3 to 4 weeks to the Philippines, Nigeria, Chile, and UAE. Call +86-135-1213-1526 or WhatsApp 86-135-12131526 for a firm delivery date.
Send Us Your Parameters for a Same Day Quotation
We do not give generic prices. Our engineers select the liner, electrode, and flange rating based on your real process data. Send us your flow range (m3/h or kg/h), fluid name and concentration, temperature (°C), pressure (bar), pipe size (DN), and required electrical output. Send the details to [email protected] or message us on WeChat: +86 13512131526. You will get a quotation with datasheets within 4 hours during China business hours.