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『Flowvis Fv-2 Flow Meter Review: Evaluating Longevity and Calibration Accuracy in Chlorinated Water』Related information(clamp on meter|electromagnetic meter|venturi meterrotameter|orifice meter|ultrasonic flow meter|mass flow meter|coriolis mass flow meter|coriolis flow meter|magnetic flow meter|magmeter flow meter|magflow flow meter|mag meter flow meter|electromagnetic flow meter|vortex flow meter|turbine flow meter|thermal mass flow meter|thermal flow meter|rotameter flow meter)
Flowvis Fv-2 Flow Meter Review: Evaluating Longevity and Calibration Accuracy in Chlorinated Water
Quick Answer: The Flowvis Fv-2 flow meter holds calibration well in clean water but drifts after 12 to 18 months in chlorinated water. If free chlorine is above 0.5 mg/L, plan a calibration check every 6 months. For long term chlorinated water service, Silver Instruments recommends an electromagnetic flow meter with a PTFE liner and Hastelloy C electrodes.
We tested three Flowvis Fv-2 units at a potable water plant in Vietnam. The line ran with 0.6 to 1.2 mg/L free chlorine. Pipe sizes were DN50 and DN80. Flow ranged from 8 to 65 m3/h. Pressure stayed near 4 bar. Temperature was between 22 and 28 °C. The test period lasted 14 months.
Calibration drift in chlorinated water
The Fv-2 units left the factory with an accuracy of 0.5 percent of reading. We verified this against a calibrated master meter. After 6 months, the error was 0.8 percent. After 12 months, the error reached 1.6 percent. After 14 months, one DN50 unit showed 2.4 percent error at 20 m3/h. This drift is small for raw water but not acceptable for custody transfer or chemical dosing.
In practice, most engineers skip a calibration schedule for battery powered or low cost meters. Chlorine changes that. The Fv-2 electrode tips formed a thin brown deposit during the test. This deposit raised electrode impedance from 18 kΩ to 47 kΩ. Higher impedance causes signal noise and slow response. The meter did not fail. It just became less reliable.
Longevity factors in chlorinated water
We opened one DN50 unit after 14 months. The EPDM liner showed hardening near the flange face. The 316L electrode tips had light pitting. The ground ring had minor corrosion. These are normal failure modes in chlorinated water. The flow body and electronics remained sealed. No water entered the housing.
The Fv-2 is not a bad meter. It works for clean water, HVAC loops, RO permeate, and irrigation lines with low chlorine. But chlorinated potable water shortens its calibration interval. We have seen this on customer sites many times. A water treatment plant in the Philippines reported similar drift after 16 months on a DN100 Fv-2. Another customer in Indonesia saw unstable readings when chlorine spiked after shock dosing.
Installation notes
The Fv-2 needs a straight run of 10 pipe diameters upstream and 5 diameters downstream. In our test, the DN80 meter sat after a 90 degree elbow with only 6 diameters of straight pipe. This added about 0.4 percent error at high flow. After we moved the meter to a longer straight run, the error dropped. Air bubbles also caused spikes. Install an air release valve upstream if the water line has entrained air.
Use grounding rings if the pipe is plastic or lined. The Fv-2 signal can become unstable without a good earth reference. In chlorinated water, a poor ground connection accelerates electrode noise. Check the ground cable every 3 months.
When the Fv-2 makes sense
The Fv-2 fits budgets where accuracy of 1 to 2 percent is acceptable. It is easy to install on small lines from DN15 to DN100. It works well for clean water and cooling water. It also fits non potable process water and low pressure irrigation return lines. If the water has no chlori
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For chlorinated water above 0.5 mg/L, we recommend a different meter. The Silver Instruments SX-MAG electromagnetic flow meter is built for this service. It has a PTFE liner and Hastelloy C electrodes. Accuracy is 0.2 percent of reading. It covers DN15 to DN300. Output options are 4-20 mA HART and RS485 Modbus. The sensor is available with IP68 protection. Use the SX-MAG for water treatment plants, distribution lines, and wastewater effluent with residual chlorine.
Recommended replacement for chlorinated water
Silver Instruments SX-MAG electromagnetic flow meter. Sizes from DN15 to DN300. PTFE liner. Hastelloy C electrodes. 0.2 percent accuracy. 4-20 mA HART output. RS485 Modbus RTU. Flange connections to EN 1092-1 or ANSI B16.5. Operating pressure up to 16 bar. Temperature up to 80 °C. For low conductivity chemical dosing lines, consider a Silver Instruments oval gear flow meter. For mass flow measurement of sodium hypochlorite or chlorine dioxide, a Coriolis mass flow meter is a better option.
We do not recommend a turbine meter in chlorinated water. The rotor bearings wear quickly. A vortex meter can work but only if the flow profile is stable. Electromagnetic meters are the simplest choice for this application.
FAQ
Can the Flowvis Fv-2 handle chlorinated wastewater?
It can run for short periods. If chlorine is below 0.5 mg/L and solids are low, it works. For chlorinated wastewater with sludge or high solids, use an electromagnetic flow meter. The SX-MAG with PTFE liner handles this better.
How often should the Fv-2 be calibrated in chlorinated water?
Check the calibration every 6 months if free chlorine is above 0.5 mg/L. If the error exceeds 1.5 percent, clean the electrodes and recalibrate. If drift returns quickly, replace the meter with a chlorine rated electromagnetic flow meter.
What is the actual drift after one year?
In our test, the Fv-2 drifted from 0.5 percent to 1.6 percent after 12 months. At 14 months, one unit reached 2.4 percent. Your drift depends on chlorine level, temperature, flow rate, and grounding quality.
Which Silver Instruments flow meter replaces the Fv-2 in chlorine service?
The Silver Instruments SX-MAG electromagnetic flow meter is the direct replacement. It has a PTFE liner and Hastelloy C electrodes. Accuracy is 0.2 percent. It is available from DN15 to DN300 with 4-20 mA HART and RS485 Modbus.
What details do you need for a quote?
Send us your pipe size in DN, flow range, pressure in bar, temperature in °C, and chlorine concentration in mg/L. Also tell us the output required, such as 4-20 mA HART or Modbus. Call +86-135-1213-1526 or WhatsApp 86-135-12131526. WeChat ID: +86 13512131526. We will reply with a model and price.
Final note: The Flowvis Fv-2 works, but chlorinated water shortens its useful calibration life. If you need billing accuracy or stable dosing control, choose a meter with a PTFE liner and Hastelloy C electrodes. Silver Automation Instruments supplies flow meters for water treatment sites in Southeast Asia, Oceania, Latin America, Africa, and the Middle East. Send your process details to our team at flow-meter.com.au or call the numbers above.