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『Flow Meter Application Guide: Sizing the Best Sensor for Slurries, Corrosives, and Gases』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)
Flow Meter Application Guide: Sizing the Best Sensor for Slurries, Corrosives, and Gases
Quick Answer: For slurry, use an electromagnetic flow meter with a rubber or polyurethane liner and velocity above 1.5 m/s to prevent solids from settling. For corrosive chemicals, select a meter with PTFE or PFA liner and Hastelloy C electrodes or a Coriolis meter with Hastelloy C tubes. For gas, a thermal mass flow meter handles low pressure air and biogas, while a vortex flow meter suits steam and compressed air.
Slurry Service: Match Liner, Electrode, and Velocity
Here is the thing. Slurry flow meters fail when solids settle or liner wears through. A Silver Instruments electromagnetic flow meter works for most conductive slurries in mining, dredging, and food waste. The meter has no moving parts and the full bore design does not clog.
Size the meter for line velocity between 1.5 m/s and 5 m/s. Below 1.5 m/s sand, ore fines, or sludge can drop out of suspension. Above 5 m/s the liner wear rate rises fast. For abrasive ore slurry in Africa, we specify a polyurethane liner and tungsten carbide electrodes. For kaolin or bentonite slurry, EPDM rubber liner with stainless steel electrodes is enough.
For heavy slurry, we often derate the flow meter to 70 percent of maximum flow to reduce liner wear. A paint manufacturer in Southeast Asia ran a Silver Instruments electromagnetic flow meter on a latex line for 14 months without liner wear. The line velocity stayed at 2.2 m/s and the liner was polyurethane.
In practice, most engineers skip the conductivity check on slurry water and then wonder why the meter reads zero. The minimum conductivity is 5 µS/cm. Check µS/cm before you buy. If the carrier liquid is oil or solvent, an electromagnetic flow meter will not read. Use a Coriolis mass flow meter instead.
For slurry with solids content above 35 percent by weight, ask us about a flow tube with a larger electrode head and grounding rings. We usually add PTFE grounding rings on plastic or lined pipe.
Corrosive Chemicals: Liner and Electrode Pairing Saves Money
Corrosive chemical flow meters need two decisions. The first is liner material. The second is electrode material. For hydrochloric acid, sulfuric acid, and caustic soda, a Silver Instruments electromagnetic flow meter with PTFE liner and Hastelloy C electrodes works well. The temperature limit is 120 °C for PTFE. Above that use PFA.
Do not use stainless steel electrodes in nitric acid or hot acid. We have seen 316L electrodes in phosphoric acid pit in 6 weeks. Use Hastelloy C or titanium. For seawater desalination, a Silver Instruments electromagnetic flow meter with PFA liner and titanium electrodes is standard.
For small doses of acid or additive, a Silver Instruments Coriolis mass flow meter with Hastelloy C tubes gives mass flow and density. It handles low flow rates from 0.5 kg/h to 500 kg/h and viscosity up to 100 cP. It is common on DN15 to DN25 chemical dosing lines. A customer in the Middle East used a Coriolis meter with Hastelloy C tubes on a concentrated sulfuric acid line at 40 °C and 0.6 bar g. The meter has run for 18 months without tube failure.
We stock electromagnetic flow meters from DN10 to DN600. For corrosive chemical lines, most customers choose DN25 to DN80. The meter outputs 4-20 mA HART and can include RS485 Modbus.
Gas Service: Thermal Mass or Vortex Depends on Pressure and Flow
Gas flow meter sizing depends on pressure, temperature, and flow turndown. For dry compressed air, nitrogen, and biogas at low pressure, a Silver Instruments thermal
Most engineers skip the minimum Reynolds number check and then lose signal at low flow. For steam, wet gas, or high vibration lines, use a Silver Instruments vortex flow meter. It handles DN25 to DN200, pressure up to PN40, and temperature up to 250 °C. Keep the gas velocity above 3 m/s for steam and above 5 m/s for air at line pressure.
Do not install a vortex meter right after a control valve. The turbulent jet destroys the vortex shedding signal. We have seen this fail on a compressed air line in a food plant in Australia. The meter was moved 15 pipe diameters downstream and the signal returned.
Last year a customer in Vietnam asked us to size a thermal mass flow meter for biogas from a palm oil mill. The gas was wet, 45 °C, and 0.2 bar g. We specified an insertion probe with PTFE coating and a remote display. The flow range was 50 kg/h to 1200 kg/h.
For biogas, natural gas, or solvent vapor service, order the Silver Instruments SIT-TMF with ATEX Zone 1 approval. For high value gas or custody transfer, a Silver Instruments Coriolis mass flow meter gives density and mass flow in one device. It works for gas flow from 0.1 kg/h to 20 000 kg/h depending on pipe size.
Data You Need Before Requesting a Quote
Request a quote: Send us your pressure (bar), temperature (°C), pipe size (DN), and flow range in kg/h or m3/h. Also send the fluid name, solids content, particle size, and conductivity in µS/cm if you know it. For gas, add gas composition, moisture level, and minimum and maximum flow. If the line temperature varies more than 10 °C, ask for a PT100 temperature input. This detail helps us pick the right liner, electrode, and sensor type.
Silver Instruments Recommended Models
For slurry, the Silver Instruments SIT-EMF electromagnetic flow meter with polyurethane or EPDM liner covers DN25 to DN600. For corrosive chemicals, the same SIT-EMF with PTFE or PFA liner and Hastelloy C electrodes covers DN10 to DN150. For gas, the SIT-TMF thermal mass flow meter suits air and biogas from DN50 to DN300. The SIT-VF vortex flow meter suits steam and compressed air from DN25 to DN200. For mass flow and density on corrosive or high value gas, the SIT-CMF Coriolis flow meter covers 0.5 kg/h to 30 000 kg/h.
Call Silver Instruments at +86-25-68650347 or message us on WhatsApp at +86-25-52155837. WeChat ID is +86 15365082610. We will reply within one working day.
FAQ: Five Questions Engineers Ask
Which flow meter is best for abrasive slurry? An electromagnetic flow meter with polyurethane liner and tungsten carbide electrodes works for most abrasive slurries. Keep velocity between 1.5 m/s and 5 m/s.
Can an electromagnetic flow meter measure corrosive acid? Yes. Use PTFE liner and Hastelloy C electrodes for acids like hydrochloric and sulfuric acid. For hot acid, use PFA liner.
What is the minimum conductivity for an electromagnetic flow meter? The liquid needs 5 µS/cm or higher. Below that, use a Coriolis mass flow meter.
Thermal mass or vortex for compressed air? For dry compressed air at low pressure with a wide turndown, choose thermal mass. For steam or wet gas, choose vortex.
What information do you need for a gas flow meter quote? Gas composition, pressure bar, temperature Celsius, pipe size DN, minimum and maximum flow kg/h, and moisture level.