Current position > Contact Us
Quick Answer: Insertion electromagnetic flow sensors measure conductive water in large mains without cutting the pipe. They fit DN150 to DN3000 lines and often reach ±0.5% to ±1.0% of reading after proper insertion depth setting. Send your pipe size, pressure, temperature, flow range, and conductivity to Silver Automation Instruments for a quick model selection and price.
Full-bore electromagnetic flow meters on a DN1000 or DN1600 water main become heavy and expensive. Inline meters need flanges, spool pieces, cranes, and line shutdown. Insertion probes avoid most of that.
An insertion electromagnetic sensor goes into the pipe through a ball valve. The probe reaches the average velocity point and measures the induced voltage from water passing through a magnetic field. No moving parts sit in the line. The result is lower installed cost for large pipe sizes and faster payback for district metered areas.
For smaller lines, Silver Instruments stocks inline electromagnetic flow meters from DN15 to DN300. Above DN150, insertion probes usually win on installed cost. Water and treated wastewater have viscosity close to 1 cP. Viscosity does not affect electromagnetic measurement as long as the fluid is conductive.
Silver Automation Instruments supplies these probes to water utilities, engineering contractors, and flow meter distributors in Southeast Asia, Latin America, the Middle East, Africa, and Oceania. The same probe family handles raw water, potable water, cooling water, brine, and treated wastewater.
Insertion electromagnetic flow sensors do not measure the whole pipe cross-section directly. They sample velocity at one point. The meter works on Faraday law. A magnetic field is generated around the electrodes. Water moving through the field produces a small voltage. That voltage is proportional to average velocity when the insertion depth is correct.
For a round pipe with a fully developed flow profile, the average velocity point sits at about 1/8 of the pipe internal diameter from the wall. Most engineers set the insertion depth from the pipe wall to this point. This detail matters on DN600, DN900, and DN1500 mains. If the insertion depth is wrong, the meter reads high or low.
Wet calibration on a flow rig helps. Silver Instruments offers insertion probes with calibration certificates traceable to national standards. Typical accuracy is ±0.5% of reading for velocities from 0.5 m/s to 10 m/s. In practice, field installation conditions such as short straight runs or upstream pumps can shift the result. We have seen this on customer sites many times. A flow conditioner or a different insertion depth setting often fixes the error.
Hot tap installation is the normal method for large water mains. The technician welds or bolts a saddle and ball valve to the pipe. The insertion probe passes through the ball valve under pressure. Because the pipe stays pressurized, hot tap installation suits city networks where shutdown means service interruption. No draining is needed.
Use 10D upstream and 5D downstream straight run as a starting point. That means a DN800 meter needs about 8 meters of straight pipe before the probe and 4 meters after it. If you have less straight run, say 5D upstream, tell us before ordering. We can adjust the insertion depth or select a probe with a flow conditioning algorithm.
Mount the probe on a horizontal pipe at the 3 and 9 positions. This avoids gas collection at the top and sediment interference at the bottom. The water should be conductive, normally above 20 µS/cm. Most municipal water is above 50 µS/cm. Desalinated water may need a conductivity check because very clean permeate can fall below the minimum.
The transmitter outputs 4-20 mA HART, pulse, and RS485 Modbus RTU. Some models accept an external PT100 for temperature compensation and data logging. Power supply options include 24 V DC and 85 to 260 V AC. The display shows flow rate in m3/h, totalized volume, and diagnostic codes. Optional ATEX Zone 1 approval is available for wastewater plants with methane hazard areas.
A water utility in Manila uses insertion electromagnetic probes on DN900 raw water lines from a river intake. They monitor daily abstraction volume and detect leakage between zones. A desalination plant in Chile measures brine discharge on a DN600 HDPE pipe. The probe uses titanium electrodes and a PVDF body because the fluid is corrosive seawater brine.
A district cooling plant in Dubai installed insertion probes on DN1000 chilled water mains. The flow data feeds the building management system through Modbus. A wastewater plant in South Africa uses a DN750 insertion probe on an effluent line. The probe is retracted every six months for electrode cleaning without stopping the flow.
These are not rare cases. Most large water mains above DN600 become more economical with insertion sensors than with full-bore meters. The purchase price is lower and the installation labor is much lower.
Do not send a general inquiry that says you need a water flow meter. We need process data to select the right insertion probe. Send us pipe diameter in DN or inches, pipe material, fluid type, conductivity in µS/cm, pressure in bar, temperature in °C, and flow range in m3/h. Also tell us the output signal you need and the power supply available on site.
For a typical DN1000 potable water main running 200 to 2000 m3/h at 6 bar and 25 °C, we often recommend a hot tap insertion electromagnetic flow sensor with 4-20 mA HART and a carbon steel saddle. For brine or seawater, we use titanium electrodes and a PVDF or PTFE body. For wastewater with high solids, we add a retractable probe and a cleaning port.
Contact Silver Automation Instruments for a model selection and price. Tel: +86-25-68650347. Whatsapp: +86-25-52155837. WeChat: +86 15365082610. Website: flow-meter.com.au.
Q: Can an insertion electromagnetic flow sensor measure clean water in a DN1000 main?
A: Yes. Clean water with conductivity above 20 µS/cm works well. The meter needs the correct insertion depth and enough straight run. Typical accuracy is ±0.5% to ±1.0% of reading.
Q: Does the pipe need to be empty for installation?
A: No. Hot tap installation allows the probe to be installed and retracted under full line pressure. This is the main advantage for large water mains that cannot be shut down.
Q: What is the minimum conductivity for an insertion electromagnetic flow probe?
A: Most models require at least 20 µS/cm. Municipal water, raw water, cooling water, and wastewater are usually fine. Very pure water or condensate may need a different flow technology.
Q: How does insertion probe accuracy compare to a full-bore electromagnetic meter?
A: Full-bore meters are generally more accurate, often ±0.2% to ±0.5% of reading. Insertion probes typically reach ±0.5% to ±1.0% of reading when installed correctly. For large mains the cost savings often outweigh the small accuracy difference.
Q: How do I choose between insertion and inline electromagnetic flow meters?
A: Use insertion probes for large pipe sizes above DN150, especially when shutdown is difficult or the budget is limited. Use inline full-bore meters for small lines, custody transfer, or applications that need higher accuracy.
Send your pipe size, fluid, pressure, temperature, and flow range to Silver Instruments. We reply with a recommended insertion probe model and price within one business day.
