• Flameproof/explosion proof housing for hazardous areas
• Certification: FM Class I Div. 1+2, ATEX/IECEx zone 1
• Up to two measuring channels, bidirectional
• Operating and standard volume flow, mass flow, optional gas energy flow rate (DGM)
• Integrated disturbance correction for more precise measurement at unfavorable measuring points
• Measurement uncertainty of the measuring system ±0.3 % MV ±0.02 ft/s, with calibration certificate traceable to NIST
• Intrinsically safe process inputs for external pressure and temperature sensors (ATEX/IECEx versions)
• HART, Profibus PA, FF H1, Modbus RTU/RS485, BACnet MS/TP (max. 1 option, depending on version)

• Natural gas and fuel gas lines in oil and gas facilities
• Process and utility gases in refineries and petrochemical plants
• Hydrogen, nitrogen, and other industrial gases in classified areas
• Gas balancing where a line break is not acceptable

• Type: ultrasonic gas flowmeter for permanent installation in hazardous areas, clamp-on
• Measurement principle: transit time difference correlation principle
• Flow direction: bidirectional
• Flow velocity: measuring range 0.03 to 115 ft/s, depending on pipe diameter
• Repeatability: 0.15 % MV ±0.02 ft/s
• Fluid: all acoustically conductive gases, e.g., nitrogen, air, oxygen, hydrogen, argon, helium, ethylene, propane
• Measurement uncertainty of the measuring system: ±0.3 % MV ±0.02 ft/s, includes calibration certificate traceable to NIST (with aperture calibration of the transducers)
• Measurement uncertainty at the measuring point: ±1 to 2 % MV ±0.02 ft/s
• Temperature compensation: corresponding to the recommendations in ANSI/ASME MFC-5.1-2011
• Physical quantities: operating volumetric flow rate, standard volumetric flow rate, mass flow rate, flow velocity, optional: gas energy flow rate (DGM)
• Totalizer: volume, mass, optional: gas energy (DGM)
• Number of measuring channels: 1, optional: 2
• Power supply (FM Class I Div. 1 version): 100 to 240 V/50 to 60 Hz or 20 to 32 V DC
• Power consumption (FM Class I Div. 1 version): <8 W
• Response time: 1 s (1 channel), option: 0.02 s
• Housing material (FM version): cast aluminum EN AC 44200 mod, special heavy-duty coating (C5 according to EN ISO 12944)
• Degree of protection (FM version): TYPE 4X/IP66
• Weight: aluminum housing 14.3 lb, stainless steel housing 34.4 lb
• Fixation: wall mounting, 2" pipe mounting
• Display: 128 x 64 pixels, backlight
• Data logger: max. 800 000 measured values
• Hazardous area, FM: Cl. I Div. 1, GP. A, B, C, D / T6 (for Group A, conduit seal of connection compartment is required within 18 inches) or Cl. I Div. 1, GP. B, C, D / T6, depending on version; Cl. II, Div. 1, GP. E, F, G / T6; Cl. III, Div. 1 / T6; Cl. I, II, III, Div. 2, GP A, B, C, D, F, G / T4A; Ta = -40°C to +60°C
• Hazardous area, ATEX/IECEx: zone 1 (versions with and without intrinsically safe inputs/outputs Ex ia)

Gas lines in classified areas are where inline metering is most expensive to install and most risky to maintain. The Flexim FLUXUS G831 measures gas flow with transducers clamped on the outside of the pipe and a transmitter in a flameproof/explosion proof housing, certified FM Class I Div. 1 and Div. 2 or ATEX/IECEx zone 1.

The G831 works on the transit time difference correlation principle, measures in both directions, and reports operating volume flow, standard volume flow, and mass flow, with optional gas energy flow rate (DGM). Integrated disturbance correction helps at unfavorable measuring points. The measuring system reaches ±0.3 % MV ±0.02 ft/s, with a calibration certificate traceable to NIST.

The transmitter supports up to two measuring channels and connects to HART, Profibus PA, FF H1, Modbus RTU/RS485, or BACnet MS/TP depending on the version. ATEX/IECEx versions offer intrinsically safe process inputs for external pressure and temperature sensors. For general purpose gas locations see the FLUXUS G731, and for liquids in hazardous areas the FLUXUS F831.

The FLUXUS G831 is available through AV-TEK Consulting in North America. Flexim is part of Emerson. Uncertainty at the measuring point depends on the gas and the installation, and AV-TEK reviews the application and the area classification with you before you order. Explore more clamp-on flow meters and the full Flexim range.