Magnetic flowmeter liner and electrode selection determines whether a meter will remain accurate, leak-tight and maintainable in corrosive, abrasive or coating service. The process liquid contacts the liner, electrodes, seals and often grounding components. Selecting these materials by fluid name alone is unsafe because concentration, temperature, contaminants, cleaning chemistry, solids, velocity, vacuum and pressure all change the duty.
Engineering material-selection table
| Component or condition | Common options | What must be verified |
|---|---|---|
| Liner | PTFE, PFA, ceramic, polyurethane and rubber families, depending on meter model | Chemical compatibility, continuous and cleaning temperature, pressure/vacuum rating, permeation, abrasion and flange installation limits |
| Electrode | 316L stainless steel, nickel alloy, tantalum, titanium, platinum-alloy and other model-specific materials | Corrosion at actual concentration and temperature, galvanic effects, coating, abrasion and availability in the selected size |
| Electrode geometry | Standard, protruding/bullnose or flush/flat designs on selected families | Balance resistance to coating against exposure to solids impact; confirm manufacturer-specific construction |
| Grounding/reference | Grounding electrodes, rings or disks; conductive piping connection | Pipe material, liner, electrical continuity, cathodic protection, stray current and manufacturer wiring instructions |
| Process seal | Elastomer or fluoropolymer grades by connection and design | Process and cleaning chemicals, temperature cycling, steam exposure and decompression behaviour |
| Fluid mechanics | Velocity, solids size/loading, entrained gas and coating tendency | Erosion, liner impact, electrode noise, empty-pipe risk and whether another measuring principle is more robust |
No table can make the final compatibility decision without the chemical supplier’s current data and the exact meter construction. Treat material names as candidate families, not universal recommendations.
Start with a complete chemical description
Record every normal and abnormal liquid that can contact the meter: product, carrier liquid, concentration range, pH, dissolved salts, oxidizers, solvents, solids and cleaning or sterilization chemicals. Include maximum continuous temperature, short cleaning temperature, operating pressure, vacuum exposure and the duration of each condition. A liner or electrode that performs well in a dilute chemical at ambient temperature may not be suitable at high concentration or temperature.
For multi-product lines, evaluate the worst credible combination rather than the most common recipe. If the chemistry cannot be bounded, ask the manufacturer for written compatibility review and consider a spool material coupon or a different measuring principle.
Select the liner for chemistry, temperature and mechanics together
Fluoropolymer liners such as PTFE and PFA are widely offered for chemical service, but their temperature, vacuum and installation limits are model-specific. Elastomer liners may be attractive for water, wastewater and abrasive slurries, while ceramic tubes can provide a different combination of wear and chemical resistance. These descriptions are starting points only.
Mechanical damage is as important as corrosion. Abrasive particles attack the liner’s leading edge; excessive flange torque can deform or crack a liner; vacuum can challenge some constructions; and high velocity can accelerate wear. Where solids are present, supply particle type, size distribution, concentration and expected velocity. Review protective rings or grounding rings only when the manufacturer confirms that their material and geometry suit the duty.
Select electrodes by corrosion and surface behaviour
316L stainless steel is a common economical electrode material, but it should not be treated as chemically universal. Nickel alloys, tantalum, titanium and platinum-alloy options exist for more demanding services, yet each has its own limitations. The correct material depends on the exact solution, concentration, temperature, redox condition and contamination limits.
Electrode shape also matters. A protruding geometry may help expose the sensing surface to the moving liquid when coating is a concern. A flush design can reduce direct impact in abrasive service. Availability and performance vary by product family, so do not copy an electrode code from one manufacturer or meter series to another.
Do not overlook grounding and full-pipe conditions
An electromagnetic meter needs a stable electrical reference to the process liquid. Conductive unlined metal pipe may provide that reference when installed exactly as instructed; lined or non-metallic pipe commonly requires grounding rings, disks or electrodes. Cathodically protected pipe and electrically noisy locations need manufacturer-specific treatment. The signal cable, shield, transmitter grounding and potential-equalization arrangement must follow the meter manual.
The measuring tube must also remain full. Avoid high points where gas accumulates, downward open discharges and locations where the pipe can drain. On horizontal pipe, choose an orientation that keeps the electrodes wetted and reduces the chance that settled solids or bubbles cover them. See the broader flowmeter installation checklist for piping-layout questions.
Verified product-family examples
| Product family | Current manufacturer-listed wetted options | Engineering use |
|---|---|---|
| Endress+Hauser Proline Promag P 300 | PFA or PTFE liners; 316L, Alloy C22, tantalum, platinum or titanium electrodes | Compare liner temperature limits and electrode compatibility for process liquids before ordering. |
| Yokogawa ADMAG AXG | Ceramic or PFA liner families are listed on the current AXG product page | Evaluate aggressive, abrasive or hygienic duty against the selected size, connection and construction. |
| Yokogawa ADMAG AXW | The ADMAG family overview lists PTFE, polyurethane, natural soft rubber and natural hard rubber among AXW liner families | Useful screening range for water, wastewater and larger-line applications; verify exact model availability. |
| Rosemount 8705 | Multiple liner, electrode, electrode-geometry and grounding options are documented by Emerson | Use the current sizing and material guide to match chemistry, abrasion and pipe construction. |
Selection checklist for an RFQ
- Liquid name, full composition, concentration range, pH and conductivity
- Normal and cleaning temperatures, including duration and frequency
- Operating/design pressure and any full-vacuum condition
- Solids type, particle size, concentration and abrasiveness
- Minimum, normal and maximum volumetric flow or velocity
- Pipe size, schedule, material, internal lining and flange standard
- Grounding, cathodic-protection and electrical-noise conditions
- Required accuracy, output, power, enclosure and hazardous-area approval
Product paths for detailed evaluation
Compare the Endress+Hauser Promag P 300, Promag W 300 and Promag H 300. Yokogawa options include ADMAG AXG and ADMAG AXW. For the Rosemount platform, review the Rosemount 8705 sensor.
Official technical references
- Emerson magnetic flowmeter liner and electrode selection guide
- Endress+Hauser Proline Promag P 300 official product page
- Yokogawa ADMAG AXG official product page
- Yokogawa ADMAG Total Insight official family overview
Request a quotation
Send the complete process and cleaning chemistry, concentration, conductivity, pressure, temperature, solids data, minimum/normal/maximum flow, pipe construction, preferred connection, power, output and hazardous-area requirements to sales@santanfluid.com. For material review and quotation, contact SANTAN on WhatsApp China +86 136 9022 3185 or WhatsApp Indonesia +62 823 1767 3750.