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『Electromagnetic Flow Meter Specification Sheet: Lining Materials and Pressure Ratings』Related information(v cone flow meter|rotary gas meter|gallon meter|gear meter|metal tube rotameter|glass tube rotameter|nutating disk meter|transit time ultrasonic flow meter|wedge flow meter|pd meters|hydraulic flow meter|ultrasonic water flow meter|water flow meter|air flow meter|magnetic water flow meter|oxygen flow meter|gas flow meter|argon flow meter|air velocity meter|gasoline flow meter|fuel flow meter|ultrasonic water meter|digital water meter|nitrogen flow meter|solid flow meter|Oxygen tank flow meter|digital water flow meter|diesel fuel flow meter|steam flow meter|02 flow meter|compressed air flow meter|oil flow meter|liquid flow meter)
Electromagnetic Flow Meter Specification Sheet: Lining Materials and Pressure Ratings
Quick Answer: Lining material controls chemical compatibility, temperature limit, and vacuum tolerance. Pressure rating follows the flange standard and the liner softening point. For most water and wastewater applications choose EPDM with PN16 or ASME 150. For aggressive acids and solvents choose PTFE or PFA with the same pressure class but confirm the temperature derating.
Several engineers miss one detail on the electromagnetic flow meter specification sheet. They select a pressure class but forget that the lining material changes the practical pressure limit at high temperature. Here is the thing. A PTFE liner rated at PN16 at 20 °C may not handle full PN16 at 150 °C continuous. The supplier has to derate the pressure. Last year a customer in Vietnam ordered DN150 seawater flow meters for a desalination plant. The pressure was 14 bar and the temperature stayed below 40 °C. EPDM liner with PN16 flanges worked without problems.
Lining materials you will see on the specification sheet
Silver Instruments supplies electromagnetic flow meters with five common liner materials. Each one fits a different process.
PTFE liner is the default for strong acids, strong alkalis, and solvents. The temperature range is roughly -25 to 180 °C. PTFE resists most chemical attack and is common in chemical plants in Thailand and Malaysia. But PTFE does not like vacuum or rapid temperature swings.
PFA liner performs like PTFE but has better high temperature and vacuum behaviour. PFA fits fine chemical dosing, aggressive cleaning chemicals, and food grade processes. Many food and beverage plants select PFA with sanitary connections. A paint manufacturer in Southeast Asia ordered DN25 PFA lined meters for solvent based paint. Operating pressure was 20 bar and the fluid temperature stayed near 60 °C.
EPDM liner fits potable water, raw water, wastewater, and seawater. The usual temperature range is 0 to 80 °C. It resists chlorine and ozone in municipal water. EPDM is not for solvents, oils, or strong oxidizers.
Polyurethane liner works well in abrasive slurry, mining tailings, and dredging. It handles solids up to about 10 percent by weight. Temperature limit is around 80 °C. Do not use polyurethane with strong acids or ketones.
Hard rubber liner is another option for slurry and high solids flows. It resists abrasion and some weak acids. Hard rubber suits mineral processing, sand water, and pulp stock.
Pressure ratings by flange standard
Pressure rating on the specification sheet depends on the process connection. Silver Instruments builds electromagnetic flow meters with EN, ASME, and JIS flanges. Common EN pressure classes are PN10, PN16, PN25, and PN40. Common ASME classes are 150 lb and 300 lb. JIS 10K and 20K are standard for many Southeast Asia projects.
For DN15 to DN600 water lines, PN16 is the most common choice. For DN700 to DN3000 water lines, PN10 is normal because large diameter pipe pressure is lower. For chemical dosing and refinery units, PN25 or PN40 appear more often. For ASME piping, 150 lb covers many water and wastewater services. 300 lb is common for high pressure chemical or offshore service.
Do not confuse the nominal pressure class with proof pressure. The factory hydro tests each body at 1.5 times the rated pressure. But the soft liner may be the limiting part at high temperature. For example, PTFE at 180 °C requires a reduced pressure rating on many designs. Ask the supplier for a pressure temperature curve before submitting the purchase order.
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>How lining and pressure rating work together
The electromagnetic flow meter body and electrodes measure flow. The liner isolates the fluid from the metal body. If the liner softens, the fluid can reach the body and damage the meter. That is why pressure and temperature are specified together.
A water treatment plant in Saudi Arabia ordered DN300 electromagnetic flow meters for a cooling water line. Operating pressure was 8 bar. Temperature was 28 °C. EPDM with PN10 flanges was enough. A chemical plant in Indonesia ordered DN50 meters for 25 percent caustic soda. Temperature stayed at 90 °C. The specification required PFA liner and PN25 flanges because of both chemical attack and temperature.
Most engineers skip the temperature derating. In practice, you only need to worry about this when the process runs above 120 °C with PTFE or PFA. For water and wastewater below 80 °C, standard pressure ratings work.
Minimum conductivity and electrode selection
Electromagnetic flow meters need a minimum fluid conductivity. Silver Instruments standard meters require at least 5 µS/cm. Demineralized water and some pure chemical flows may fall below this limit. Electrode material also matters. 316L stainless steel is the standard for water and wastewater. Hastelloy C and titanium fit seawater, chlorides, and weak acids. Tantalum fits strong acids. Platinum fits aggressive chemical streams and some food processes.
When you ask for a quote, state the conductivity if you know it. If you do not know it, tell us the fluid name and concentration. That helps us check the lining and electrode combination.
Requesting the right specification sheet
A clear enquiry saves time. Send us your operating pressure in bar, fluid temperature in °C, pipe size (DN), and flow range. Also tell us the flange standard and the fluid name. That is enough for Silver Instruments to return a full electromagnetic flow meter specification sheet with lining material, pressure rating, electrode type, and accuracy statement.
For quotes contact Silver Automation Instruments. Call +86-25-68650347. WhatsApp +86-25-52155837. WeChat: +86 15365082610. Our team responds with a datasheet that matches your pipe schedule and process conditions. Standard outputs include 4-20 mA HART, pulse, and Modbus RTU. We can also advise on ATEX Zone 1 approvals if your site needs them.
FAQ: Lining materials and pressure ratings
Question 1: Can one liner handle both acid and alkaline fluids?
PTFE and PFA handle most acid and alkaline fluids. EPDM is limited to water and light chemicals. Check the chemical compatibility list before ordering.
Question 2: What pressure rating should I choose for a DN200 water flow meter?
PN16 is the typical choice for DN200 water lines. If site piping uses ASME flanges, choose 150 lb. Always compare the site design pressure with the meter pressure class.
Question 3: Does the lining material reduce the pressure rating?
Yes at high temperature. PTFE and PFA soften above 120 °C. The allowable operating pressure drops. For normal water and wastewater below 80 °C, the effect is small.
Question 4: Which lining is best for seawater desalination?
EPDM with 316L electrodes and PN16 flanges is a proven combination. If the cleaning chemicals are aggressive, use PFA liner and Hastelloy C electrodes.
Question 5: Can Silver Instruments supply PN25 or PN40 electromagnetic flow meters?
Yes. Send pipe size, operating pressure, fluid temperature, and flange standard. We confirm the liner, electrode, and body material for PN25 or PN40 service.
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