Ultrasonic Flow Meters
Transit-Time Flow Measurement For Liquids
DN6 to DN6000, sixteen models across three install styles
Reads any liquid regardless of conductivity
5–7 business days, factory direct
- 40 ps time-difference resolution. Low-voltage multi-pulse balanced design.
- Three install styles: external mount, inline / spool, insertion + billing.
- ISO 9001 calibration certificate ships with every meter.
Ultrasonic flow meters measure liquid or gas flow by transit-time difference between paired transducers. Our UFM family covers DN3 to DN6000 across eighteen models: sixteen liquid (clamp-on, inline, insertion, water, BTU; reads any liquid above the 5 microsiemens per cm conductivity floor that EMF cannot) and two gas (CSUF transit-time, DN25 to DN200, clean dry natural-gas and industrial-gas service). Lead time 5 to 7 business days.
Ultrasonic flow meter models
Nineteen models; 17 liquid (valflux + taosonics + ULFC factory-direct handheld) at DN3 to DN6000, plus 2 gas (CSUF transit-time) at DN25 to DN200.
External mount on existing pipe
Clamp-On Ultrasonic Flow Meter
External transducer pair clamps to the host pipe with coupling gel and stainless straps. No pipe cut, no shutdown. Three transducer pairs (S/M/L) cover the full bore range.
View model →Compact Clamp-On (±2.0 %)
Compact form factor for sub-DN200 plant water branches, secondary verification, packaged-skid sub-loops. OLED, 1.54-inch IPS, or 2.4-inch IPS display versions. Optional PT100 BTU pair.
View model →Quick-Install Non-Weld
Outer-mount integrated clamp body bolts around host pipe OD with two screws. Pre-aligned transducer spacing; no field measurement needed. Residential entry, commercial sub-utility, lab dosing.
View model →Small-Pipe Sub-DN10
Lab and instrument-tubing scale, sub-DN10 service. Clamp-on V-method transducer pair on stainless, PVC/CPVC, PVDF, PEEK, PTFE, copper, or borosilicate tubing.
View model →Portable Standard
Battery handheld for spot checks, HVAC commissioning, contractor visits. 20-hour Ni-MH battery, 2 GB SD card data log, optional CT-1 PT100 pair for portable BTU work.
View model →Precision Handheld (±0.5 %)
Precision-grade handheld for commissioning validation, ISO 50001 audit, district-heat warranty, billing reconciliation. 2.8-inch (P6) or 3.5-inch (P8) IPS LCD; ISO 9001 cal cert in the kit.
View model →Handheld Walk-Up (±1 %)
Single-hand pocket walk-up reader for leak survey, basement loop verification, and contractor first-look diagnostic. 4-line LCD, built-in 2000-line data logger, RS-232 + Frequency Output + OCT. The entry-grade handheld; route BTU work to Portable, ISO-traceable handover to Precision Handheld.
View model →Inline pipe-segment and spool body
Inline Ultrasonic Flow Meter
Sealed flow-tube body, wafer or flanged, factory-calibrated as one unit. The internal straight length removes the 10D/5D field rule. Use on new construction.
View model →Single-Path U6 (±1.0 %)
Single-path inline; ±1.0 % uniform across inline, wall-mount, and BTU configurations. Lowest-cost option in the single-path line. Plant trending and secondary metering.
View model →Single-Path U7 (±0.5 % inline)
Mid-grade single-path. ±0.5 % on inline (C8); ±1.0 % on wall-mount (W8) and BTU versions. Plant primary and commercial sub-measurement where inline ±0.5 % is needed.
View model →Single-Path U8 (±0.5 %)
High-grade single-path. ±0.5 % across all four configurations (inline / wall-mount / with-BTU / without-BTU). 0.15 % repeatability. Industrial primary and district-heat trunk.
View model →Multi-Path M2 (2-channel)
Two-path averaging absorbs upstream profile asymmetry. 5D/3D straight-pipe footprint vs single-path 10D/5D. For short straight runs and post-bend installs.
View model →Multi-Path M4 (4-channel)
Four-path Gaussian-quadrature sampling for severe-disturbance tolerance and custody-grade measurement. 0.10 % repeatability; tightest in the family. Large-bore municipal and industrial billing.
View model →Spool Piece (2-channel)
Two-path inline spool-piece body, drops into the line as a single flanged segment with built-in transducer pairs. Combines multi-path accuracy with inline factory-calibration.
View model →Insertion and billing meters
Insertion Ultrasonic Flow Meter
Single-point probe inserts through a welded ball valve under live pressure. No service shutdown. Nikuradse 1/8-D profile correction. Large-bore retrofit on cast iron, cement-lined, and HDPE mains.
View model →Ultrasonic Water Meter
Battery integrated body for residential, commercial, and DMA billing. NB-IoT, LoRa, or GPRS wireless AMR on V56-V64 firmware. Smart-card prepaid and valve-control on V62. IP68 submersible.
View model →Ultrasonic BTU Meter
Wall-mount heat meter pairs transit-time flow with a PT100 supply and return pair (CT-1 clamp-on or in-line well). On-board firmware solves the energy integral. M-BUS EN 13757 output.
View model →Gas service ultrasonic (CSUF series)
Mid-grade transit-time gas builds for clean dry service. Distinct from the liquid UFM models above.
Natural Gas Ultrasonic (CSUF)
Transit-time gas flow on dry single-phase natural gas, town gas, fuel gas headers, and industrial-park distribution mains. Zero pressure drop, bidirectional, 1:100 turndown. Mid-grade accuracy for distribution and industrial-park aggregation; LWGQ turbine holds the higher-accuracy bulk-billing position.
View model →Industrial Gas Ultrasonic (CSUF)
Transit-time on N2 distribution headers, compressed-air mains audit, industrial dry-gas sub-measurement. Zero pressure drop is the USP at DN150 / DN200 mains where blower or regulator margin is tight. 3.6 V battery + 4G option for unmanned ISO 50001 audit endpoints.
View model →How transit-time ultrasonic flow measurement works
Transit-time ultrasonic measurement pairs two transducers across the flow stream. One faces upstream, one faces downstream. The on-board firmware alternates pulses in both directions and resolves the time difference to 40 ps. The difference is proportional to velocity; the proportionality constant is fixed in the factory calibration table.
The advantage over electromagnetic flow meters: transit-time reads any liquid regardless of conductivity. DI water, RO water, glycol blends, and light hydrocarbon up to 10 cSt all read on the UFM family. The 5 microsiemens per cm electromagnetic floor does not apply. Trade-offs: the signal fails on partial pipe-fill, and it degrades above 10,000 ppm suspended solids.
When to specify ultrasonic vs electromagnetic / vortex / turbine
| Service | Ultrasonic (UFM); pick when | Alternative meter type |
|---|---|---|
| Low-conductivity liquid (DI / RO / glycol / oil) | Standard pick; reads regardless of conductivity | EMF cannot read below 5 microsiemens per cm floor |
| Retrofit on existing pipe, no shutdown | Clamp-on or insertion install with no pipe cut | EMF inline and vortex require pipe-cut install |
| Large bore (DN1000+ trunk main) | Clamp-on to DN6000, insertion to DN3000 | Vortex tops at DN1000, EMF inline at DN3000 with cost-prohibitive civil works |
| Bi-directional flow (return mains, reverse-flow) | Native bi-directional with reverse-flow detection | Turbine + orifice are uni-directional |
| Slurry above 10 000 ppm suspended solids | Above the meter tolerance, sound scattering corrupts signal | LEA polyurethane-lined slurry model |
| High-viscosity hydrocarbon above 10 cSt | Sound attenuation increases above 10 cSt; not the right pick | Coriolis (ZLMFM) or turbine |
| Clean dry natural gas / industrial gas / fuel gas distribution | CSUF transit-time gas series; DN25 to DN200, ±1.0 % to ±1.5 % of rate, mid-grade distribution / industrial-park accuracy | LWGQ gas turbine for ±0.5 % bulk billing; LQ Roots for low-flow tenant fence-inlet sub-billing; vortex (LUGB) for fuel-gas to boilers |
| Steam, wet gas, 2-phase service, cryogenic gas | Not the right pick; ultrasonic transit-time degrades on wet / 2-phase / cryogenic service | Vortex (LUGB) for steam; LUXB swirl for wet biogas / raw gas; Cryogenic Coriolis for LNG / LH₂ / LOX |
| Custody-grade utility billing | Not shipped from the factory. ISO 4064, OIML R49, and MID are buyer-arranged with the local notified body. | Coriolis (ZLMFM) for custody-grade liquid mass flow |
Universal install requirements.
Five rules apply to every ultrasonic install. Model-specific notes live on each model page.
- Respect the straight-pipe rule. Clamp-on: 10D upstream, 5D downstream, 30D after a pump. Inline factory-calibrated: 3D / 2D. Insertion: 5D / 3D. Plan the pipe routing at design stage.
- Verify pipe-fill before measurement starts. The pipe must stay 100 % liquid-filled. Air pockets falsify the transit-time signal. Closed-loop systems need an air vent on the loop high point upstream of the meter.
- Match transducer or probe to host-pipe material. Clamp-on supports steel, stainless, cast iron, copper, PVC, PE, HDPE, GRP, and cement-lined pipe. Scale-coated pipe may need acoustic coupling treatment. The inline body and water meter are sealed units.
- Run sensor cable separately from power cabling. Use the supplied shielded cable (SEYV75-2 for clamp-on and insertion), maximum 500 m sensor-to-converter, and keep 300 mm clear of VFD and motor-drive cabling.
- Align flow direction with the arrow on the meter body. Most models are bi-directional, but the calibrated forward direction is marked on the body or probe. Verify direction at commissioning.
Frequently asked questions
Need help selecting an ultrasonic flow meter?
Send application type, pipe DN range, medium, and install context. Reply in one business day. Lead time 5–7 business days from the factory.