Rosemount 3417 Redundant 4+4 4-Path Gas Ultrasonic Flow Meter

Two custody meters in one body for fully redundant gas measurement

The Rosemount 3417 is a fully redundant gas ultrasonic flow meter that combines two field-proven 4-path, British Gas-design meters in a single body, so two independent measurements are made in one meter run. Emerson positions it for pipeline interconnects, pipelines without bypass, border stations, offshore production, city gates, power plants and LNG regasification terminals. It is available in DN200 to DN1050 with 3410 Series Electronics and transducers engineered for wet, rich or dirty gas. Firmware runs AGA 8 Part 2 speed-of-sound calculations in real time for comparison with the meter’s own measured speed of sound, and extensive hourly and daily logs let operators trend the two meters over time, which Emerson says can help extend calibration cycles.

Technical specifications

Selecting between redundant and single meters

Choose the 3417 when uptime or a contractual dispute makes a single measurement path set too risky, for example where there is no bypass, at remote offshore sites, or when two contracting parties both want their own measurement in a pay-check arrangement. A bidirectional line can dedicate one transmitter to forward and one to reverse flow. The T-200 transducers can be extracted under pressure without special tools and have a non-wetted design that removes the possibility of greenhouse gas emissions. The MeterLink software and Smart Meter Verification provide expert flow analysis and a simplified measurement status result, available through Modbus or MeterLink.

Ordering notes

The datasheet includes sizing tables by line size and operating pressure, weights and dimensions, recommended pipe lengths and a configurator code. Material of construction, flange class and transducer type must be specified by the customer, and the configurator code determines the final build. See other metering products in Flowmeters.

Key features of the 3417

• Two independent 4-path chordal meters in one spool, each with its own transmitter and eight transducers.
• ±0.1% of reading calibrated accuracy and ±0.05% repeatability across the stated velocity band.
• Compliance with AGA 9 and ISO 17089, plus OIML R137 Class 0.5 and MID Class 1.0 for fiscal applications.
• Transducer options for wet, rich or dirty gas and for low temperatures down to -50 °C.
• Real-time AGA 8 speed-of-sound comparison and hourly and daily logs for condition-based monitoring.
• Line sizes from DN200 to DN1050 and flange classes up to ANSI 1500.

How redundancy improves measurement confidence

In custody transfer, a single meter fault can mean lost revenue or a disputed invoice. With two meters measuring the same gas in the same body, the operator continuously compares their flow readings. If the two agree within an agreed tolerance, confidence in the measurement is high. If they drift apart, the diagnostics of each meter (path velocities, gain, signal-to-noise, speed of sound against the AGA 8 value) help identify which one has a problem, such as a fouled transducer or a changed flow profile. Meanwhile, the healthy meter keeps the station measuring, which is valuable on pipelines with no bypass where the meter run cannot be shut down easily.

Installation considerations

• Ultrasonic meters are sensitive to flow profile. Provide the upstream and downstream straight lengths and flow conditioner layout specified by Emerson and the applicable standard (AGA 9 or ISO 17089).
• Install pressure and temperature measurement at the positions the standard requires so flow can be converted to standard volume or energy.
• Avoid sources of ultrasonic noise close to the meter, such as partly open control valves, or allow for them in the design.
• Plan transducer access: retractable mounts or isolation arrangements simplify maintenance on live lines where they are offered.
• Route communications from both transmitters to the flow computer and SCADA so the comparison is visible to operators.

Maintenance and verification

Routine work focuses on reviewing diagnostics rather than mechanical service. Trending speed-of-sound deviation, path ratios and profile factors from the logs reveals deposits, liquid build-up or conditioner damage early. Emerson notes that this monitoring can help extend calibration intervals; the final interval remains a matter for the contract and the regulator.

Applications in Oman and the GCC

Gas transmission networks, export and import interconnections, LNG terminals, power and desalination plants and industrial city gates in the region all use fiscal gas metering. High ambient temperatures and sun exposure on outdoor skids should be considered when locating electronics and sunshades, and wet or rich gas from upstream processing can make the dirty-gas transducer option worth discussing.

What to include in your RFQ

• Line size, flange rating and facing, and end connection type.
• Gas composition, pressure, temperature and flow range (minimum, normal, maximum).
• Required approvals: OIML, MID, local metrology, NACE, PED or NORSOK.
• I/O and communication requirements to the flow computer.
• Calibration requirements and any witness testing.

Documents and quotation

The Emerson product data sheet 00813-0100-3417 (Rev AJ, June 2024) is attached. Please send line size and flange class, gas composition, operating pressure and temperature, forward or bidirectional duty, material and NACE or NORSOK needs, and hazardous-area and metrology approvals, and we will prepare a quotation against the manufacturer configurator.