Swirl Flow Meters
Precession Swirl Flow Meters for Tight Skids
Accuracy of ±0.5% of rate
Turndown ratio of 1:30
Straight-pipe install 3D upstream / 2D downstream
- Line sizes DN25 to DN300
- Pressure class PN16 to PN250 (1.6 to 25 MPa) standard; up to 42 MPa factory custom
- 6 models on the LUXB Series
The LUXB Precession Swirl family meters gas, steam, and liquid across DN25 to DN300. Precession-swirl off a fixed generator gives ±0.5 % of rate over a 1:30 turndown, with built-in temperature and pressure compensation outputting mass flow in kg/h or Nm³/h.
Six models span the gas, steam, and LPG-vapor applications below. The 3D / 2D straight-pipe rule fits branch spools where vortex needs 10D / 5D. CNEX Ex d IIC T6 Gb ships standard; lead time 5–7 business days.
Swirl flow meter models
Six models on the LUXB Series. Click through for spec, configurator, and pricing.
Natural Gas Swirl
Custody-grade natural gas on M&R stations, CHP feed lines, and factory inlets. Built-in T+P with on-board AGA-style compressibility correction.
View configuration →Biogas Swirl
Raw digester gas on WWTP, agricultural digester, landfill, and CHP-feed lines. Hastelloy C-276 wetted parts handle H₂S to 10,000 ppm continuous.
View configuration →Hydrogen Swirl
Low-density hydrogen on PEM electrolyzer feeds, refinery sub-meters, and laboratory test rigs where vortex sensor signal drops below noise.
View configuration →Nitrogen / Oxygen Swirl
High-purity industrial N₂ and O₂ on inerting headers, blanket-gas feeds, ASU plant outlets, and electronic-grade purge lines.
View configuration →Compressed Air Swirl
Factory plant-air systems on the LUXB Series. ISO 1217 Free Air Delivery output, ISO 8573-1 Class 4 humid-air tolerance, and a 3D+2D straight-pipe install.
View configuration →LPG Vapor Swirl
Vapor-phase LPG on peakshave plants, vaporizer-outlet lines, and propane-air mixing skids. utility-grade calibration cert option for utility billing.
View configuration →How precession swirl flow meters work
A precession swirl flow meter measures volumetric flow by spinning the gas through a fixed swirl generator at the meter inlet. The swirling flow contracts as it enters the throat of the meter body, and the vortex core precesses around the central axis at a frequency directly proportional to flow velocity. A piezoceramic sensor mounted outside the gas-wetted bore detects the precession through the pipe wall and converts the frequency to volumetric flow rate.
Built-in T+P compensation on the LUXB Series adds an integrated Pt1000 RTD and pressure transducer feeding the on-board flow computer. The compensated output is mass flow in kg/h or volumetric flow in Nm³/h on the 4-20 mA loop. Because the inlet swirl generator dominates upstream velocity profile, the meter is immune to upstream disturbance after just 3× DN of straight pipe; a quarter of what vortex meters require.
Swirl versus vortex versus thermal mass
Choose swirl when straight-pipe is short or the medium is low-density. Choose vortex for steam-heavy service across DN15 to DN600. Choose thermal mass for wet or low-velocity service.
| Service | Swirl (LUXB); pick when | Alternative meter type |
|---|---|---|
| Straight pipe < 10D upstream | 3D+2D fits tight skids | Vortex needs 10D/5D |
| Hydrogen, low-density gas | Inlet swirl generator dominates signal | Vortex below shedding floor |
| Oxygen, ignition-sensitive service | No bluff body in bore | Vortex bluff body present |
| Wet biogas with H₂S | Hastelloy C-276 standard, no bluff body | Vortex noisy below 5 m/s wet |
| Custody-grade utility billing (LPG, NG) | utility-grade calibration cert option available | Coriolis above 6.3 MPa |
| Steam (saturated & superheated) | Steam swirl available, but vortex preferred | Vortex (LUGB) for full DN range |
| High pipe size DN300+ | Beyond LUXB range | Vortex (LUGB) DN15–DN600 or insertion |
| Idle leak drift, off-shift trickle | Below swirl precession floor | Thermal mass (TMF) at 0.1 Nm/s floor |
Swirl model selection by gas service
Match the LUXB build to the gas service. Six models across the LUXB precession-swirl family cover the full gas measurement range where vortex (LUGB) straight-pipe runs are unavailable.
| Service | Wetted-parts & configuration | Model page |
|---|---|---|
| Raw biogas, AD digester, landfill gas | Hastelloy C-276 wetted parts (sour-service standard) | Biogas Swirl |
| Compressed-air sub-measurement, ISO 50001 / 11011 audit | 316L wetted parts, FAD-equivalent Nm³/h output | Compressed Air Swirl |
| Hydrogen (PEM electrolyzer, refinery, HRS) | H₂-clean wetted parts, CNEX Ex d certified | Hydrogen Swirl |
| LPG vapor (peakshave plant, vaporiser outlet) | Integrated heat-trace termination, four blend profiles | LPG Vapor Swirl |
| Natural gas (city-gate, fuel gas, sub-measurement) | 316L wetted parts, built-in T+P compensation | Natural Gas Swirl |
| Industrial nitrogen and oxygen (ASU, blanketing, oxy-fuel) | 316L wetted parts, dual-gas calibration | Nitrogen / Oxygen Swirl |
All six models share the LUXB Series: ±0.5 % of rate, 1:30 turndown, built-in T+P compensation, 3D upstream / 2D downstream straight-pipe rule (vs vortex 10D/5D), CNEX Ex d IIC T6 Gb option, 5–7 business days lead time.
Model specification comparison.
| model | DN range | Pressure class | Wetted parts | Key positioning |
|---|---|---|---|---|
| Biogas | DN50–DN300 | ≤ 1.6 MPa | Hastelloy C-276 | Sour-service standard, H₂S to 10,000 ppm |
| Compressed Air | DN25–DN300 | ≤ 1.6 MPa | 316L | FAD-equivalent Nm³/h, ISO 50001 audit |
| Hydrogen | DN25–DN200 | ≤ 1.6 MPa standard | H₂-clean materials | PEM / alkaline / refinery, CNEX Ex d |
| LPG Vapor | DN25–DN200 | ≤ 4.0 MPa | 316L + heat-trace box | Peakshave + vaporiser, four blend profiles |
| Natural Gas | DN25–DN300 | ≤ 6.3 MPa option | 316L | City-gate sub-measurement, fuel gas |
| N₂ / O₂ | DN25–DN400 | ≤ 6.3 MPa option | 316L | ASU outlet, blanketing, oxy-fuel burner |
All models share the LUXB Series: ±0.5 % of rate, 1:30 turndown, built-in T+P compensation, 3D/2D straight-pipe rule, CNEX Ex d IIC T6 Gb option, 5–7 business days lead time.
Universal LUXB install requirements
The LUXB precession-swirl family shares install requirements across all 6 models.
- Send the gas service and operating range at order timeThe factory K-factor depends on the configured gas (NG / biogas / N₂ / O₂ / H₂ / compressed air / LPG blend) and the operating pressure and temperature. Composition variance beyond ±5 % requires the live composition input option.
- Respect 3D upstream and 2D downstream straight pipeThe fixed swirl-generator at the inlet straightens flow inside the meter body, so the LUXB tolerates 3D / 2D where the LUGB vortex needs 10D / 5D; the Series advantage on tight skid installs.
- Confirm the hazardous-area zone on the quoteCNEX Ex d IIC T6 Gb (flameproof, Zone 1, gas group IIC) ships as standard for hazardous-area orders. Verify the site zone classification at quote stage so the matched cert documentation ships.
- Wire only the loop you need; no external T+P transmittersTemperature and pressure are read on-board, so the field wiring runs only the 4-20 mA loop (or RS485, or HART) back to the DCS. Eliminates the 4-instrument vortex + T + P + flow-computer stack.
- Install with the bore filled; no partial-fill operationThe swirl precession signal corrupts on a partially-filled bore. Especially after long horizontal runs that may pool condensate (biogas / saturated NG) or oil mist (post-compressor air), specify upstream KO-pot or top-mount probe option.
Frequently asked questions
Need help selecting a swirl flow meter?
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