Natural Gas Ultrasonic Flow Meter

Mid-Grade Transit-Time Metering for Industrial-Park Gas

Accuracy ±1.0 % / ±1.5 % of rate
DN25 to DN200 inline flanged build, single-path or dual-path
1:100 turndown standard, 1:160 by order

  • Near-zero pressure drop; no obstruction in the bore, no rotor, no bluff body
  • Bidirectional readback for reverse-flow or load-balancing service on industrial-park feeders
  • Ex d IIC T6 Gb flameproof + IP65 + 24 V DC or 3.6 V lithium battery for Automated Meter Reading (AMR)
↓ Request datasheet (PDF)
Crystal A Crystal B Δt path Gas flow → Transit-time ultrasonic spool Paired crystals at oblique angle, Δt resolved to mean velocity DN25 to DN200 · Single-path or dual-path build

Transit-time gas flow measurement for industrial-park mains, fuel-gas-to-boiler headers, town-gas regulator-station accounting, and wholesale-billing aggregation between regulator and downstream meters. Mid-grade ±1.0 % to ±1.5 % of rate on DN25 to DN200, 1.6 MPa ceiling, single-path or dual-path. In-scope service: clean dry natural gas, town gas, fuel gas, or compressed air post-dryer. Out-of-scope service (wet / 2-phase / cryogenic LNG / raw biogas) goes to the swirl, vortex, or Coriolis family per medium.

Benefits

  • Near-zero pressure drop: no obstruction in the bore. Industrial-park feeders running low post-regulator pressure keep their head.
  • 1:100 turndown standard, 1:160 by order: one meter covers off-peak / shoulder / peak diurnal swing on a distribution main.
  • Bidirectional readback: handles reverse-flow and load-balancing service on industrial-park feeders without re-piping.
  • No moving parts, no rotor wear: zero-wear electronics for clean dry gas service, no rotor service cost over the life cycle.
  • Seven output options: pulse, 4-20 mA (2-wire or 3-wire), RS-485 Modbus, HART, 4G wireless for utility telemetry.
  • Ex d IIC T6 Gb flameproof + IP65: classified industrial-park service with sealed housing.
  • Lead time 5–7 business days from the factory.

Configure your build.

Select your specs and the configurator returns the CSUF model code plus a ballpark unit price. Submit for engineering review and verified sizing within 4 business hours.

Your Configuration

CSUF-80-U-A-Ex-5-T-2-1-1
Pipe sizeDN80
Power24 V DC
Accuracy±1.0 % of rate
Hazardous areaEx d IIC T6 Gb
OutputRS-485 Modbus RTU
Spool material304 stainless
Path countSingle-path
CompensationPressure
Form factorIntegrated
Estimated unit price
Verified after engineer review
$2,440
Subtotal (× 1)$2,440
Request Quote on This Build Email Engineering
✓ Ex d IIC T6 Gb flameproof
✓ Gas composition reviewed by application engineer
✓ Reply within 4 business hours

Typical applications

Four applications where mid-grade transit-time gas flow measurement wins on diurnal swing and zero rotor wear.

🏭

Industrial-park gas mains aggregator

DN100 to DN200 campus header feeding multiple tenants. 1:100 turndown captures shift swings. Mid-grade accuracy supports inter-tenant cost allocation.

🔥

Fuel-gas-to-boiler / CHP feed

DN80 to DN150 boiler-house header. Wide turndown holds part-load firing. Bidirectional readback covers transient cross-flow on tied combustion grids.

🏙

Town-gas regulator-station accounting

DN150 to DN200 wholesale-billing aggregator between regulator and downstream meters. Off-peak diurnal flow stays inside the 1:100 turndown range.

📍

Distribution sub-station feeder accounting

Post-regulator low-ΔP distribution main 0.4 to 1.6 MPa. Near-zero pressure drop keeps line head; no rotor wear on diurnal cycling.

Specifications

Measurement principleTransit-time ultrasonic; paired crystals at oblique angle, Δt between downstream and upstream pulse proportional to mean axial velocity
Path countSingle-path (1) or dual-path (2)
Pipe size rangeDN25, DN50, DN80, DN100, DN150, DN200 (six sizes)
Flow range (air reference)DN25: 0.4 to 40 m³/h · DN50: 1.6 to 160 · DN80: 4.0 to 400 · DN100: 6.5 to 650 · DN150: 16 to 1,600 · DN200: 25 to 2,500 m³/h
Accuracy±1.0 % of rate (class A) or ±1.5 % of rate (class B); headline figure applies above the transition flow Qt = 0.1 × Qmax
Accuracy spec (per range)Class A: ±1.0 % of rate from Qt to Qmax · Class B: ±1.5 % of rate from Qt to Qmax · Below Qt (Qmin ≤ Q < Qt) accuracy widens to ±2 % of rate for both classes. Qt = 0.1 × Qmax by default; 0.0625 × Qmax on the 1:160 special-order turndown build.
Repeatability±0.1 %
Turndown1:100 standard; 1:160 by order (specify at order)
Working pressureUp to 1.6 MPa standard; extended pressure by quote
Medium temperature−10 to +50 °C standard; −40 to +60 °C special
Ambient range−20 to +60 °C, ≤ 95 % RH non-condensing
Spool materialCarbon steel / 304 stainless / 316 stainless / special (configurable)
MediumClean dry natural gas, town gas, fuel gas, post-upgrade biomethane, post-dryer compressed air
Service exclusionsWet gas, condensate-bearing service, 2-phase, raw biogas, cryogenic, steam, pulsating service without accumulator
CompensationNone / temperature / pressure (selectable per Comp field in configurator)
Output signalsPulse 3-wire, pulse + battery-card, 4-20 mA 3-wire / 2-wire, RS-485 Modbus RTU, HART, 4G wireless
Power supply24 V DC or 3.6 V lithium battery (battery suited for off-grid AMR endpoints)
DisplayLCD; instantaneous flow, cumulative volume, temperature and pressure if compensated
Form factorIntegrated (1) / remote split (2)
Process connectionFlanged spool body, GB/T 9119-2010 compatible at PN1.6
Ingress protectionIP65
Hazardous areaEx d IIC T6 Gb (flameproof)
Straight pipe≥ 10 D upstream, ≥ 5 D downstream from nearest disturbance
ApprovalsEMC 2014/30/EU (Annex II), ISO 9001 calibration record with each meter
Lead time5–7 business days from factory

Installation

Five install rules. Pre-condition: clean dry single-phase gas at the meter inlet.

  1. Straight pipe ≥ 10 D upstream and ≥ 5 D downstream Measured from the nearest fitting, elbow, valve, or branch on either side of the spool. The transit-time method reads mean axial velocity along the path; swirl and asymmetry inside the path bias the reading.
  2. Gas filter upstream of every meter A line-service gas filter must precede the meter. Particulate fouls the crystal faces and shifts zero. Place the filter outside the 10 D upstream run so it does not generate its own swirl into the spool.
  3. Pressure regulator upstream of the meter Distribution and industrial-park service needs a regulator upstream to stabilize inlet pressure within the meter range. Steady inlet pressure protects the path geometry and standard m³/h reporting through the T+P compensation channel.
  4. Avoid wet gas, 2-phase service, and condensate carry-over Liquid carry-over blocks the crystal face and distorts the acoustic path. If the line risks condensate during upset, fit a knockout pot upstream. Saturated and 2-phase service goes to the swirl-flow-meter (LUXB Series).
  5. Locate the meter at least 10 D from any pulsation source Compressors, blowers, and other pulsation sources degrade transit-time averaging. Mount the meter at least 10 D downstream of any such source, or fit an accumulator upstream if pulsation is unavoidable.

Frequently asked questions

How does a transit-time natural gas ultrasonic flow meter work?+
A pair of crystals is mounted at an oblique angle across the spool. One pulse fires downstream and rides the gas flow; the return pulse fires upstream and fights the flow. The time difference Δt between the two transit times is proportional to the mean axial velocity along the path, and the spool cross-section converts that velocity to volumetric flow at line conditions. Optional temperature and pressure inputs correct line m³/h to standard m³/h. The principle has no moving parts and no obstruction in the bore; pressure drop is near zero. The CSUF Series ships single-path or dual-path on DN25 through DN200, with ±1.0 % of rate or ±1.5 % of rate accuracy options.
How does this differ from the natural-gas-turbine counterpart?+
Different jobs. The LWGQ natural-gas-turbine flow meter is a velocity-rotor instrument at ±0.5 % of rate that holds the high-accuracy billing position on DN50 to DN300, 1.6 to 10 MPa, with a 1:30 turndown. The CSUF natural-gas-ultrasonic flow meter sits in the mid-grade distribution slice; ±1.0 % to ±1.5 % of rate, DN25 to DN200, 1.6 MPa ceiling, 1:100 turndown standard. Pick the turbine when the service needs the tighter accuracy at high steady flow and the line will tolerate rotor wear. Pick this ultrasonic build when the service is industrial-park aggregation, fuel-gas-to-boiler, or wholesale-billing at a regulator station; where flow swings widely, the line cannot afford rotor wear, and mid-grade accuracy is enough.
What does "G-class" mean and does this meter use it?+
G-class is the EN 1359 / EN 12480 gas-meter sizing designation used by positive-displacement and turbine gas meters; G16 / G25 / G40 / G65 and so on indicate the Qmax rating of a meter for clean gas service. The CSUF Series uses direct DN-and-flow-range tables instead, because ultrasonic transit-time reads volumetric flow directly from the velocity profile rather than from a calibrated displacement. Each CSUF DN has a published Q range on air at reference conditions: DN25 covers 0.4 to 40 m³/h, DN50 covers 1.6 to 160, DN80 covers 4.0 to 400, DN100 covers 6.5 to 650, DN150 covers 16 to 1,600, and DN200 covers 25 to 2,500. For natural gas at line conditions, the velocity-to-volume conversion is the same; for standard m³/h reporting, temperature and pressure compensation is added through the configurator.
Does the meter ship with a billing-cert ex-factory?+
No. The factory ships each meter with an ISO 9001 calibration record listing the calibrated DN, accuracy class, path count, and tested Q range. Hazardous-area cert is Ex d IIC T6 Gb (flameproof) and EMC compliance is to EU Directive 2014/30/EU. Country-specific billing type approval for natural-gas service; whichever local regime applies in the deployment country; is buyer-arranged with a notified body. CSUF is positioned for industrial-park aggregation, fuel-gas accounting, and wholesale-billing at distribution sub-stations, not for high-pressure transmission billing. Buyers needing tighter ±0.5 % of rate billing should specify the natural-gas-turbine counterpart instead; buyers needing G-class small-bore billing should specify the natural-gas-roots counterpart.
Can I use this meter on biogas service?+
Only on post-upgrade biomethane after H₂S scrubbing, CO₂ separation, and drying; same dry-single-phase rule as natural gas. For that service, the platform supports CSUF, but the biogas-ultrasonic related page is the primary listing. For raw biogas at the digester or pre-upgrading buffer (water-saturated, H₂S up to 10,000 ppm), go to the biogas-swirl-flow-meter (LUXB Series) which uses Hastelloy C-276 wetted parts and tolerates wet H₂S service. For small-skid biomethane at G-class billing rates, the biogas-roots-flow-meter (LQ Series) holds ±0.5 % of rate at the low-flow tail. For high-flow grid-injection billing on RNG skids, the biogas-turbine-flow-meter (LWGQ Series) covers DN50 to DN200.
What is the lead time and what ships with each meter?+
Standard lead time is 5 to 7 business days from order confirmation, factory direct. Each meter ships with an ISO 9001 calibration record listing the calibrated DN, accuracy class, path count, and tested Q range; a mill cert for the carbon-steel or stainless spool body; the build-coded serial plate with the model string; and the install dimensional drawing for the configured DN. Hazardous-area cert is Ex d IIC T6 Gb (flameproof) for classified industrial-park and refinery service. EMC compliance to EU Directive 2014/30/EU ships standard with IP65 ingress. The 3.6 V lithium battery option ships pre-fitted with a multi-year service life for off-grid AMR billing endpoints; the 4G wireless output option is paired with battery power for utility-telemetry service.

Need help sizing a natural gas ultrasonic build?

Send line size, gas P/T, composition, flow range. Reply in 1 day; lead time 5–7 business days from the factory.