Nitrogen & Oxygen Swirl Flow Meter

A precession swirl meter has no bluff body in the bore; only smooth-cast inlet swirl vanes; and the dual piezoceramic differential sensor reads the precession frequency from behind the pipe wall, outside the gas-wetted bore. Two consequences matter for nitrogen and oxygen service. First, there is nothing in the bore for particles to shed from and no wake region with stagnant gas, which is the ignition-risk concern engineers raise on bluff-body meters in oxygen lines. Second, the meter needs only 3× DN of straight pipe upstream and 2× DN downstream against the 10D / 5D a vortex meter requires, so on tight ASU plant skids the meter actually fits where the piping designer drew it. Accuracy is ±0.5 % of rate with a 1:30 turndown.

The LUXB precession swirl ships with three accuracy classes: ±0.5 % of rate, ±1.0 % of rate, and ±1.5 % of rate, where R refers to reading (not full-scale). The standard configuration on this model is ±0.5 % of rate. Repeatability is ±0.2 %. Turndown is 1:30 across the working flow range, so a single meter spans a wide demand swing without a parallel-meter bypass. Every unit ships with a factory calibration certificate traceable to a national-standard reference. The factory K-factor is set against the gas service specified at order time (nitrogen or oxygen) at the working pressure and temperature on the order; the meter is ready to drop into the line.

Pipe sizes run DN15 to DN400 (½″ to 16″); DN15 to DN200 in the standard flanged dimensional series and DN250 to DN400 in the large-diameter stainless-steel series. Pressure classes step through PN16 / PN25 / PN40 / PN64 / PN100 / PN160 / PN250 (1.6 to 25 MPa), with ANSI 150 / 300 / 600 / 900 / 1500 / 2500 LB equivalents. Most plant nitrogen blanketing, oxygen distribution, and ASU outlet services land in the DN50 to DN200 range at PN16 or PN25; the sweet spot for the integral LUXB-S transmitter. DN250 and above typically ship with the LUXB-F remote transmitter so the cabinet can sit at eye level on a manifold rack.

Yes. The on-board density table covers both nitrogen and oxygen, and the gas service is selected at order time so the K-factor and density compensation ship pre-loaded against the stated medium. For ASU plants where the same line position may run as an N₂ flow meter one shift and an O₂ flow meter the next, specify the medium-switch option at quote time and the meter ships with both density tables loaded; the operator picks the active gas through the local HMI or via a Modbus register. The 316L wetted-parts standard applies to both services. For corrosive service, Hastelloy C wetted parts are the option; flag the duty at quote time so the engineering team can confirm the build.

The LUXB needs only 3× DN of straight pipe upstream and 2× DN downstream; the same numbers apply across straight pipe, 90° elbow, concentric reducer, and concentric expander disturbances. An upstream valve adds 2D, taking the upstream requirement to 5× DN. A vortex (Karman) meter on the same line position would need 10D upstream and 5D downstream as a baseline, with longer figures (25D after a 90° elbow, 50D after a half-open valve) on disturbance-heavy piping. The compact straight-run requirement is the main retrofit advantage on a tight ASU plant skid or industrial-gas distribution rack where the original piping designer did not leave 10D of clear run.

Output signals run 4–20 mA in Nm³/h, pulse equivalent for totalizer cross-check, RS485 Modbus RTU, HART (multidrop), and GPRS or 4G IoT for remote sites. The local LCD shows working flow, Nm³/h, totalizer, live pressure, and live temperature on the same screen. Built-in temperature and pressure compensation is part of the standard configuration on this model; Nm³/h goes straight to the DCS without an external multivariable transmitter or a SCADA-side correction script.

CNEX Ex d IIC T6 Gb (flameproof, Zone 1, gas group IIC, surface-temperature class T6) ships as standard for hazardous-area orders; confirm the zone on the quote. IP65 / IP66 / IP67 ingress protection is available. EMC compliance to the EU Electromagnetic Compatibility Directive 2014/30/EU (Annex II) ships as standard, covering EN IEC 61000-6-1, -6-2, -6-3, -6-4, EN IEC 61000-3-2, and EN 61000-3-3.

5–7 business days from the factory for every configuration in this model; DN15 through DN400, integral or remote transmitter, nitrogen or oxygen service, with or without the temperature and pressure compensation options. Engineering review on the configurator submission turns around within 4 business hours and locks the LUXB 13-position model code before production starts.