Hydrogen Flow Meter

Hydrogen sits at about 1/14 the density of air at the same conditions, so Karman vortex shedding behind a bluff body is weak and noisy at the low end of the flow range. The LUXB precession swirl forces a deterministic helical core via a fixed inlet swirl generator, and the dual piezoceramic differential sensor reads the precession frequency from behind the pipe wall; outside the gas-wetted bore. The result is a clean signal across the full working range, ±0.5 % of rate, 1:30 turndown, and a 3× DN upstream / 2× DN downstream straight-pipe rule (against the 10D / 5D a vortex meter requires). On a tight electrolyser skid this is often the only swirl-class meter that fits the available straight run.

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 hydrogen model is configured at ±0.5 % of rate as standard. Repeatability is ±0.2 %. Turndown is 1:30 across the working flow range, so a single meter spans idle electrolyser leak rate through peak stack output without a parallel-meter bypass. Every unit ships with a factory calibration certificate traceable to a national-standard reference. The meter is factory-calibrated against the configured medium (pure H₂ or refinery H₂ stream) at the working pressure and temperature on the order; no separate hydrogen-correction step is needed in the field.

The LUXB ships in 304 SS, 316L stainless, or Hastelloy C wetted parts. For pure-hydrogen service from PEM or alkaline electrolyser output, 316L is the standard pick. For H₂S-bearing H₂ streams downstream of refinery hydrotreaters, specify Hastelloy C; the same Hastelloy C body the biogas model uses for sour-gas service. Material spec is locked at manufacturing, not field-swappable after the meter ships. For service ranges outside the standard range (very-high-pressure dispensing) flag the service at quote time so the engineering team can confirm whether the standard model fits.

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 PEM and alkaline electrolyser outputs and refinery off-gas hydrogen sub-meter points land in the DN25 to DN150 range at PN16 to PN64. For HRS skid inlet metering ahead of the high-pressure compressor stage, the meter sits at the inlet pressure (typically ≤ 6.3 MPa), well within the standard range.

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. The flameproof housing contains any internal arc or hot surface so the meter cannot become an ignition source for a surrounding hydrogen-air atmosphere. 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.

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 electrolyser skid or refinery sub-meter line where the original piping designer didn’t leave 10D of clear run.

5–7 business days from the factory for every configuration in this model; DN15 through DN400, integral or remote transmitter, 316L or Hastelloy C, 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.