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Rosemount™ 3418 Eight-Path Gas Ultrasonic Flow Meter
Rosemount 3418 Gas Ultrasonic Flow Meter
The new Rosemount 3418 8-path ultrasonic flow meter crafted, developed, and designed by Emerson, offers the highest accuracy and best in class performance coupled with the same high functionality required by sophisticated fiscal measurement users.
The 3418 combines the power of two interlocked 4-path British Gas design meters in one flow meter body. The second set of chords is the mirror image of the first, which allows the meter to cancel out the effects of swirl and cross flow. The 3418 Flow Meter boasts a 0.5 OIML accuracy class and requires only five diameters of straight run and no flow conditioner.
Rosemount™ 3418 Eight-Path Gas Ultrasonic Flow Meter


Line Size
DN250 to DN1050 (10-in to 42-in) with British Gas (BG) orientation
Fluid Type
±0.1% of reading relative over entire flow calibration range
±0.05% of reading for 5 to 100 ft/s (1.5 to 30.5 m/s)
Rated up to 100 ft/s (30 m/s) with over-range performance exceeding 125 ft/s (38 m/s) on some sizes
Operating Temperature Range (Transducers)
T-200: –50°C to 125°C (–58°F to +257°F)
T-21: -20°C to +100°C (-4°F to +212°F)
T-41: -50°C to +100°C (-58°F to +212°F)
T-22: -50°C to +100°C (-58°F to +212°F)
Operating Pressure Range (Transducers)
T-200: 103 to 25,855 kPag (15 to 3,750 psig)
T-21/T-41/T-22: 689 to 27,579 kPag (100 to 4,000 psig)
T-21/T-41/T-22: 345 kPag (50 psig) available with reduced Qmax
T-22: 0 to 25,855 kPag (0 to 3,750 psig)
Carbon steel and stainless steel


  • No flow conditioner reduces compression and pumping costs and eliminates maintenance due to blockages
  • High rangeability of >100:1 ensures fewer meter runs smaller line sizes and lower capital costs
  • 3410 Series Electronics provide fast sampling, an expandable electronics platform and an archive data log containing pressure, temperature and gas composition information which allows the meter to act as a redundant flow computer
  • 3410 Series Electronics calculate corrected volume rates, mass rates and energy rates
  • T-200 Transducers are safely extractable under pressure without special tools (for line sizes up to 42")
  • Significantly reduce time previously spent on data analysis and troubleshooting with the new Smart Meter Verification Basic feature now included in the latest 3410 Electronics firmware update