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OEM Manufacturer Since 2019 · Shenzhen, China

Ultrasonic Flow Meters – Clamp-On & Non-Invasive OEM Manufacturer

Factory-direct clamp-on ultrasonic flow meters for OEM equipment builders, system integrators, and facility engineers worldwide. No pipe cutting, no process shutdown — transit-time technology, DN15 to DN5000 depending on model, ±0.5% (U11) or ±1% (U10 series, U20) accuracy, 4-20mA / RS485 Modbus. CE and UKCA, IP68 clamp-on sensors. CDU liquid cooling, HVAC, water treatment, and process flow measurement.

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No pipe cutting DN15–DN5000 by model ±0.5% (U11) / ±1% CE / UKCA / IP68 sensors
SEGMENsensor U12 clamp-on ultrasonic flow meter OEM manufacturer China
±0.5%
U11 Accuracy
DN5000
Max Pipe (U11)
IP68
Sensors

Key facts

A SEGMENsensor clamp-on ultrasonic flow meter measures liquid flow from outside the pipe: two transducers send ultrasonic pulses upstream and downstream, and the transit-time difference is proportional to flow velocity. There is no pipe cutting, no process shutdown and no pressure drop. Wall-mount, one-piece and handheld models cover DN15 to DN5000 depending on the model.

Last updated · SEGMENsensor Engineering Team

Watch: how to install a clamp-on flow meter, and how it works

Clamp-On Ultrasonic Flow Meter Installation: Complete Guide
Clamp-On Ultrasonic Flow Meter Installation: Complete GuideStep-by-step installation of portable, fixed and compact clamp-on ultrasonic flow meters: site check and straight run (10D upstream / 5D downstream), pipe data, V/Z/W mounting, couplant, transducer spacing, wiring, signal strength and quick fixes.
3:56 · YouTubeChapters & transcript →Get a quote →
Transcript

Clamp-on ultrasonic flow meter installation: the complete guide, from choosing the spot to a stable reading. First, check the site. A transit-time meter needs a pipe that is always full, and a clean liquid without heavy bubbles or solids. Straight run: at least 10 D upstream and 5 D downstream. On horizontal pipes, mount at the side. Measure the real outer diameter and wall thickness. Don't rely on nominal pipe sizes: a wrong diameter gives a constant offset. Enter the outer diameter, wall thickness, pipe material and liquid. The meter calculates the transducer spacing for you. Choose the mounting method. V-mode, with both transducers on one side, is the default. Z-mode suits large or lined pipes. W-mode suits small pipes. The spacing is always measured along the pipe axis, centre to centre. Clean both transducer spots: remove paint, rust and grease. A dirty surface is the most common cause of a weak signal. Apply a bead of couplant to each transducer face. It removes the air gap, so ultrasound can pass into the pipe wall. Fit the transducers in the mounting rail at the calculated spacing. Press them firmly against the pipe and secure them with the chain fixture, so they stay parallel and cannot move. Fixed and compact meters follow the same rules. Here the fixed type is clamped in place, and the compact meter is tightened with a hex key. Connect the upstream and downstream cables to the matching ports. Keep signal cables away from motor drives and power cables. On a fixed meter, also connect the power supply and the 4–20 mA or RS485 output. Open the status page. Aim for a signal strength of 60% or more on both transducers. If it is low, clean the surface again, re-apply couplant, check the spacing, or try Z-mode. With a good signal, the meter shows flow rate, velocity and the running total. Check that the velocity makes sense for your system. If you can, close the valves and confirm a zero reading. Quick fixes. An unstable reading usually means the straight run is too short. A weak signal points to a dirty surface or air in the pipe. A constant offset usually means the pipe diameter or wall thickness was entered wrongly. SEGMENsensor clamp-on ultrasonic flow meters, in portable, fixed and compact types. Datasheets and quotes at segmensensor.com.

How a Clamp-On Ultrasonic Flow Meter Works (Transit Time)
How a Clamp-On Ultrasonic Flow Meter Works (Transit Time)One-minute animation of transit-time flow measurement: two clamp-on transducers, ultrasonic pulses with and against the flow, the time difference that gives flow velocity, and the pipe data entered at set-up.
0:56 · YouTubeChapters & transcript →Get a quote →
Transcript

How does a clamp-on meter measure flow in a closed pipe? Two ultrasonic transducers are clamped on the outside of the pipe. Nothing touches the liquid, and the pipe is never cut. Transducer one sends a pulse to transducer two, with the flow. Then transducer two sends one back, against the flow. The pulse with the flow arrives slightly sooner. The time difference is proportional to the flow velocity. Multiplied by the inner area of the pipe, it gives the flow rate. To set up, enter the pipe size, wall thickness, material and liquid. The meter then calculates the transducer spacing. SEGMENsensor clamp-on flow meters cover DN15 to DN5000, depending on the model. Learn more at segmensensor.com.

Fixed Clamp-On Ultrasonic Flow Meter (U12): Installation and First Reading
Fixed Clamp-On Ultrasonic Flow Meter (U12): Installation and First ReadingReal footage of the U12 fixed clamp-on flow meter: mount the transmitter on the pipe, connect the transducers and power, enter pipe data and watch the first reading; 4–20 mA and RS485 Modbus outputs.
1:13 · YouTubeChapters & transcript →Get a quote →
Transcript

Fixed clamp-on ultrasonic flow meter: installation and first reading. The transmitter mounts directly on the pipe. The transducers clamp to the outside, so the pipe is never cut and the liquid is never touched. Connect the transducer cables and the power supply. Using the front keys, enter the pipe outer diameter and wall thickness. The Status page then shows signal strength and quality on both transducers. At steady flow, the reading stays stable. 4–20 mA and RS485 Modbus outputs connect the meter to a PLC or SCADA system. SEGMENsensor clamp-on ultrasonic flow meters. Request a quote at segmensensor.com.

Compact Clamp-On Ultrasonic Flow Meter (U13): Assembly and Installation
Compact Clamp-On Ultrasonic Flow Meter (U13): Assembly and InstallationReal footage of the U13 compact clamp-on flow meter: assemble the clamp, apply couplant, clamp it onto the pipe with a hex key, set the pipe parameters and read live flow.
1:11 · YouTubeChapters & transcript →Get a quote →
Transcript

Compact clamp-on ultrasonic flow meter: assembly and installation. The kit contains the meter, the clamp assembly, mounting rods and a hex key. Start by assembling the clamp. The meter and the clamp then lock together into one compact unit. Apply couplant to the transducer faces. It removes the air gap, so ultrasound can pass into the pipe wall. Clamp the unit onto the pipe and tighten it with the hex key. The pipe stays closed: no cutting, no welding, no shutdown. In the menu, set the pipe size and the other pipe parameters. The display then shows the live flow rate, here in litres per minute. Clamp-on ultrasonic flow meters for OEM and industrial users. Learn more at segmensensor.com.

Portable Clamp-On Ultrasonic Flow Meter (U20): Setup in 4 Steps
Portable Clamp-On Ultrasonic Flow Meter (U20): Setup in 4 StepsReal footage of the U20 portable clamp-on ultrasonic flow meter: enter pipe data, apply couplant, mount the transducers at the calculated spacing, check signal quality, read flow, velocity and totalizer.
1:12 · YouTubeChapters & transcript →Get a quote →
Transcript

Portable clamp-on ultrasonic flow meter: set up in four steps. The kit includes a battery-powered handheld meter, a pair of clamp-on transducers, mounting fixtures and couplant. Step one. Enter the pipe outer diameter, wall thickness, pipe material and liquid type. The meter calculates the transducer spacing for you. Step two. Clean the pipe surface and apply couplant to each transducer face, so the ultrasonic signal passes into the pipe wall. Step three. Mount the transducers on the outside of the pipe at the calculated spacing, and secure them with the chain fixtures. No pipe cutting, no shutdown. Step four. Check signal strength and quality on the status screen, and fine-tune the position if needed. The meter then shows flow rate, velocity and the running total in real time. U20 fits 1"–48" (25–1200 mm) pipes, ±1% of reading. Quotes at segmensensor.com.

U12 Clamp-On Ultrasonic Flow Meter: Setup Menu Step by Step
U12 Clamp-On Ultrasonic Flow Meter: Setup Menu Step by StepStep-by-step walkthrough of the U12 setup menu: pipe outer diameter and wall thickness, liquid, transducer mounting, spacing, damping, the Status page (signal strength, quality, sound speed) and zero settings.
1:03 · YouTubeChapters & transcript →Get a quote →
Transcript

The U12 setup menu, step by step. Under Pipe Settings, enter the pipe outer diameter and the wall thickness. Here, 16 mm and 1.1 mm. Next, select the liquid. Here, it is water. Then choose the transducer mounting method. The meter calculates the transducer spacing. Damping smooths the displayed reading. The Status page shows upstream and downstream signal strength, signal quality and the measured sound speed. Zero Settings sets the zero point and the low-flow cut-off. U12: DN15–DN65, with 4–20 mA and RS485 Modbus outputs. Quotes at segmensensor.com.

Tested on our water flow test line

Water flow test line for ultrasonic flow meters at SEGMENsensor
Water flow test line for ultrasonic flow meters
Clamp-on flow meter checked on the test line at SEGMENsensor
Clamp-on flow meter checked on the test line

Every unit is tested before shipment. Photos from our own production and test lines.

Clamp-on flow metering for water supply schemes in India and other countries: see our export market pages.

Quick Answer

What is a clamp-on ultrasonic flow meter? A clamp-on (non-invasive) ultrasonic flow meter measures liquid flow by clamping transducers onto the outside of an existing pipe — no cutting, no welding, no process shutdown. Two transducers send ultrasonic pulses upstream and downstream; the time difference is precisely proportional to flow velocity. Zero contact with the liquid means zero contamination risk and no pressure drop. SEGMENsensor manufactures clamp-on ultrasonic flow meters in Shenzhen, China, covering DN15 to DN5000 depending on the model, with 4-20mA, RS485 Modbus, pulse and relay outputs.

Product Range

Clamp-On Ultrasonic Flow Meter Product Lines

Three series covering portable handheld meters, wall-mount fixed installations, and compact single-pipe configurations — all transit-time, all clamp-on, all CE certified.

SEGMENsensor U12 integrated clamp-on ultrasonic flow meter
01

U12 / U13 — One-Piece Clamp-On

U12 · U13 DN15–DN65 by model Backlit display 4-20mA / RS485

U12: one-piece clamp-on meter in a metal housing for DN15–DN65 pipes, ±2% (±1% after calibration), IP65, 10–24 V DC, any two of 4–20 mA, RS485 Modbus, OCT pulse and relay; with a PT1000 pair it works as a mini energy meter. U13: compact one-piece meter for DN15–DN40 small pipes in an acid- and alkali-resistant PP glass-fibre housing, <3% FS (<1.5% FS after calibration), 20–28 V DC, 4–20 mA and RS485 Modbus. Suited to permanent installation on small chilled-water, cooling-water and process lines in tight spaces.

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SEGMENsensor U10 clamp-on ultrasonic flow meter
02

U10 / U10S PRO / U11 — Wall-Mount

15–5000 mm by model Sensors up to +180 °C HART option IP65 / IP68

Wall-mount transmitter with separate clamp-on sensors. U10 (plastic housing, 25–1200 mm) and U10S PRO (aluminium housing, 15–1200 mm) are ±1% economy meters; the U10S PRO has a colour backlit display. U11 is the high-accuracy model: ±0.5%, repeatability 0.1%, 15–5000 mm, ±0.01 to ±12 m/s, FPGA-based TGA timing with sampling up to 300 times per second, and tolerance of intermittent bubbles or impurities lasting up to 5 seconds. Standard sensors cover −40 to +80 °C (A2); high-temperature sensors reach +130 °C (H1A) or +180 °C (H2A). Every model is also available as a heat / cooling (BTU) energy meter with PT1000 temperature sensors.

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SEGMENsensor U20 portable handheld ultrasonic flow meter
03

U20 — Portable Handheld

25–1200 mm (1–48 in) 3000 mAh, about 16 h SD card 32 GB IP68 sensors

Battery-powered handheld clamp-on flow meter for commissioning, survey and spot-check measurements. ±1%, ±0.01 to ±12 m/s, 240×128 backlit LCD, SD card up to 32 GB with a logging interval of 1–99999 s, and a rechargeable 3000 mAh lithium battery for about 16 hours per charge. P2 / P2H sensors cover −40 to +80 °C / +130 °C; F1 / F1H sensors fit DN15–DN40 pipes. Details on the U20 portable clamp-on flow meter page.

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Technical Specifications

Clamp-On Ultrasonic Flow Meter Full Specifications

Values from the SEGMENsensor model datasheets. Transit-time clamp-on flow meter manufacturer China — outputs, sensors, cable length and energy-meter version are selected in the ordering code for OEM applications.

Parameter U10 Wall-Mount U10S PRO Wall-Mount U11 High-Accuracy U20 Handheld
Measurement PrincipleTransit-timeTransit-timeTransit-timeTransit-time
Pipe Size Range25–1200 mm15–1200 mm15–5000 mm25–1200 mm (1–48 in); DN15–DN40 with F1 / F1H sensors
Accuracy±1%±1%±0.5%±1%
Repeatability0.2%0.2%0.1%—
Linearity±1%±1%——
Velocity Range±0.03 to ±5 m/s±0.03 to ±5 m/s±0.01 to ±12 m/s±0.01 to ±12 m/s (±0.03 to ±40 ft/s)
Sensor TemperatureA2 −40 to +80 °C; H1A −40 to +130 °C; H2A −40 to +180 °C; B1 / B1H (DN15–DN40) 0–65 °C / 0–115 °CA2 −40 to +80 °C; H1A −40 to +130 °C; H2A −40 to +180 °C; B1 / B1H (DN15–DN40) 0–65 °C / 0–115 °CA2 −40 to +80 °C; H1A −40 to +130 °C; H2A −40 to +180 °C; B1 / B1H (DN15–DN40) 0–65 °C / 0–115 °CP2 −40 to +80 °C; P2H −40 to +130 °C; F1 / F1H (DN15–DN40) 0–65 °C / 0–115 °C
LiquidWater (a small amount of bubbles allowed)Single, acoustically conductive liquidSingle, acoustically conductive liquid; tolerates intermittent bubbles or impurities up to 5 sSingle, acoustically conductive liquid
Output SignalsChoose two of 4–20 mA (max. load 750 Ω), pulse (OCT, 0–10 kHz), relay, RS232 Modbus, RS485 ModbusChoose two of 4–20 mA (max. load 750 Ω), pulse (OCT, 0–10 kHz), relay, RS232 Modbus, RS485 ModbusChoose two of 4–20 mA (max. load 750 Ω), OCT pulse 0–9999 Hz, relay (SPST), RS232 Modbus, RS485 ModbusChoose two of 4–20 mA, RS485 Modbus, OCT pulse, relay
Communication OptionHARTHARTHART; dual relay output (replaces RS232)—
Housing / DisplayPlastic housing, external keysU10S PRO: aluminium housing, colour backlit display, external keysWall-mount transmitterHandheld, 240×128 backlit LCD
Data StorageOptional SD card, 32 GBOptional SD card, 32 GBFcard, expandable to 32 GBSD card, 32 GB; logging interval 1–99999 s
Power Supply10–36 V DC; optional 90–245 V AC10–36 V DC; optional 90–245 V AC90–245 V AC (48–63 Hz) or 10–36 V DCRechargeable 3000 mAh lithium battery, about 16 h per charge
Protection RatingTransmitter IP65, sensors IP68Transmitter IP65, sensors IP68Sensors IP68Sensors IP68
Sensor CableStandard 9 m, custom up to 274 m (B1 / B1H: 5 m)Standard 9 m, custom up to 274 m (B1 / B1H: 5 m)Standard 9 m, custom up to 274 m (B1 / B1H: 5 m)Standard 5 m, custom up to 30 m (F1 / F1H: 3 m)
Energy (BTU) VersionHeat / cooling meter with PT1000 sensorsHeat / cooling meter with PT1000 sensorsHeat / cooling meter with PT1000 sensorsHeat / cooling meter with PT1000 sensors
CertificationsCE UKCACE UKCACE UKCACE UKCA
Samples1–5 pcs, 5–7 working days1–5 pcs, 5–7 working days1–5 pcs, 5–7 working days1–5 pcs, 5–7 working days
Lead TimeConfirmed with the quotationConfirmed with the quotationConfirmed with the quotationConfirmed with the quotation

U12 and U13 one-piece clamp-on meters (from the model datasheets)

ParameterU12 one-pieceU13 compact
Pipe sizeDN15–DN65 (two sizes: DN15–DN40, DN50–DN65)DN15–DN40
Velocity range0.03–10 m/s0.15–10 m/s
Accuracy±2% of reading; ±1% after calibration<3% FS; <1.5% FS after calibration
Liquid temperature0–65 °C standard; 0–115 °C high-temperature option−10–65 °C standard; −10–105 °C high-temperature option
LiquidsWater and other clean single-phase liquids (no solids)Water and other clean single-phase liquids (no solids)
Pipe materialsStainless, carbon steel, copper, PVC, PVDF, PPR, PPHStainless, carbon steel, copper, PVC, PVDF, PPR, PPH, PFA
OutputsAny two of: 4–20 mA, RS485 Modbus RTU, OCT pulse, 1 relay4–20 mA, RS485 Modbus RTU; optional OCT pulse or relay
Power supply10–24 V DC20–28 V DC
HousingAluminium alloy / engineering plastic housing, IP65PP glass-fibre, acid- and alkali-resistant
DisplayBacklit display256×128 backlit LCD
Low-flow cut-off (default)—0.08 m/s
Response time—0.5–60 s
Connector—M12
Energy / temperature versionE version with PT1000 pair: displays and measures liquid temperature; usable as a mini heat / cooling (BTU) meterE version: displays and measures liquid temperature
CertificationsCE UKCACE UKCA

Download the clamp-on ultrasonic flow meter datasheet (PDF)

Two-page datasheet with all ranges, accuracy classes, output options, supply voltage, sensor codes and temperature limits, IP rating, flow range by pipe size and ordering information. No registration required.

Download datasheet (PDF) U11 datasheet (PDF) More documents (CAD, wiring, certificates) Start an OEM project or request qualification samples — samples 5–7 days · reply within 24 h
Data Center Cooling

CDU Coolant Flow Monitoring — Clamp-On Ultrasonic Solution

Liquid-cooled data centers (CDU, rear-door heat exchangers, direct-to-chip cooling) demand non-invasive flow monitoring that won't contaminate the cooling loop or require system downtime to install.

CDU Coolant Flow Sensor OEM

Why Data Center Engineers Choose Clamp-On Over In-Line Flow Meters

Zero fluid contamination No pipe modification RS485 to DCIM DI water / coolant loops
  • Clamps onto existing coolant supply and return pipes — zero modification to the CDU manifold or cooling loop
  • Measures single, acoustically conductive coolants in a full pipe, such as deionized (DI) water; send your glycol mix for an application check
  • RS485 Modbus RTU output integrates directly with DCIM platforms (Schneider EcoStruxure, Vertiv Trellis, custom BMS)
  • 4-20mA output drives rack-level or room-level flow totalizers for PUE and WUE calculation
  • Energy (BTU) version adds PT1000 sensors on supply and return to measure the heat removed by the cooling loop
  • Alarm relay output for low-flow detection — protects liquid-cooled IT equipment from coolant starvation
DN15+
Small CDU manifold pipes supported
±0.5%
U11 accuracy (±1% on U10 series)
−40 to +80 °C
Standard A2 clamp-on sensor (H1A to +130 °C)
IP68
Clamp-on sensors, no pipe cutting
Compatible With
Deionized water Glycol mixes (application check) Cooling water Chilled water
SEGMENsensor U11 fixed clamp-on ultrasonic flow meter transmitter packed for a data center cooling-water order
U11 transmitter from the data center order

Case: data center cooling-water flow monitoring in northern China

A data center operator in northern China needed to monitor cooling-water flow without shutting down or cutting the pipes. After an on-site sample trial, the customer ordered 40 units of U11 fixed clamp-on ultrasonic flow meters; inquiry to order took about three weeks.

Measuring points, BMS integration and BTU metering for data center loops: data center chilled water flow monitoring guide →

Comparison

Clamp-On vs Insertion Ultrasonic Flow Meters — Which to Choose?

SEGMENsensor specializes in clamp-on (external) technology. Here is an honest comparison to help OEM engineers select the right type for their application.

Criterion Clamp-On (SEGMENsensor) Insertion Ultrasonic Electromagnetic (Mag) Differential Pressure
Pipe Modification ✓ None — external clamp Drill + hot-tap required Full pipe cut, flanges Full pipe cut, flanges
Liquid Contact ✓ Zero — non-invasive Wetted probe Wetted electrodes Wetted orifice plate
Pressure Drop ✓ Zero Minimal Low High (orifice)
Installation Time ✓ < 2 hours 4–8 hours 1–2 days (shutdown) 1–2 days (shutdown)
Best Pipe Size DN15–DN5000 depending on model DN100–DN2000 DN15–DN3000 DN25–DN1000
CDU / Coolant ✓ Ideal — no contamination Risk of leakage Only for conductive fluids Not recommended
Accuracy ±0.5% (U11) / ±1% (U10 series, U20) ±1–±2% ✓ ±0.3–±0.5% ±0.5–±2%
OEM Cost ✓ Low (factory direct) Low–Medium High Medium
Why SEGMENsensor

Factory Direct — Not a Distributor

UKCA Marked

Flow meter datasheets carry CE and UKCA marking for the EU and UK markets.

CE Certified

EMC directive compliance. CE declaration of conformity for EU customs clearance.

Qualification samples

Samples of 1–5 units ship in 5–7 days. Private-label versions are quoted by quantity.

Since 2019

Direct factory in Shenzhen since 2019 — in-house assembly and calibration, not a trading company.

Applications

Where Clamp-On Ultrasonic Flow Meters Are Used

Non-invasive flow measurement wherever pipe cutting is impractical, contamination is unacceptable, or retrofitting an existing system. Clamp-on flow meter OEM factory — specify your pipe and fluid below.

Data Center CDU Cooling
CDU coolant flow sensor OEM — non-invasive on DI water and glycol lines. DCIM integration via RS485 Modbus.
HVAC Chilled Water
Flow balancing and energy metering on chilled water supply and return. Compatible with building BMS via RS485.
Water Treatment Plants
Raw water intake, clarifier feed, filtration output, and distribution flow measurement on mains up to DN5000 with U11.
Thermal Energy Metering
Energy-meter (BTU) versions add PT1000 supply and return temperature sensors to calculate heating and cooling energy.
Industrial Cooling Loops
Compressor oil cooling, injection moulding machine cooling water, CNC spindle cooling — flow monitoring without loop modification.
Chemical Process
Clamp-on sensors never touch the liquid, so there are no wetted parts to corrode; the compact U13 has an acid- and alkali-resistant PP glass-fibre housing.
Building Management
Domestic hot water, condenser water and grey water recycling flow monitoring. Integration with BMS via RS485 Modbus.
Pharmaceutical / Food
Non-contact measurement ensures zero product contamination. CIP (clean-in-place) compatible — no dead legs or crevices.
Clamp-On Flow Meter Manufacturer China

Why OEM Engineers Source Ultrasonic Flow Meters From SEGMENsensor

SEGMENsensor manufactures clamp-on ultrasonic flow meters as a direct factory in Shenzhen — not a distributor, not a trading company. In-house transducer bonding, PCB assembly, firmware development, and in-house calibration ensure consistent quality across every OEM batch.

2019
Founded
Direct factory in Shenzhen
OEM volume supply
Order Quantity
Qualification samples: 1–5 units
5–7 days
Sample Lead Time
Quoted FOB China · import duty by country
±0.5%
U11 Flow Accuracy
±1% on U10 series and U20
SEGMENsensor U13 portable ultrasonic flow meter – OEM manufacturing
OEM Customization Available
  • Model and sensor matched to your pipe (DN15–DN5000 by model)
  • Output: choose two of 4-20mA / RS485 Modbus / RS232 Modbus / OCT pulse / relay; HART option
  • High-temperature sensors up to +180 °C (H2A)
  • Sensor cable up to 274 m on wall-mount models
  • Private label / OEM branding: your faceplate and nameplate, English menu, neutral packaging
  • CE and UKCA documentation included
FAQ

Frequently Asked Questions — Ultrasonic Flow Meters

Common questions from OEM engineers and system integrators. Email info@segmensensor.com for application-specific advice — we reply within 24 hours.

Principles and measurement

What is a clamp-on ultrasonic flow meter and how does it work?
A clamp-on ultrasonic flow meter attaches transducers to the outside of a pipe without cutting or drilling. Two transducers fire ultrasonic pulses alternately upstream and downstream through the pipe wall and liquid. The difference in transit time between upstream and downstream pulses is proportional to the flow velocity. Because nothing touches the liquid, there is zero contamination risk and zero pressure drop.
What is the difference between clamp-on and insertion ultrasonic flow meters?
Clamp-on meters are external and non-invasive — no pipe drilling, no wetted parts, zero contamination risk, installable while the system runs. Insertion meters require drilling a hole and inserting a probe into the flow. SEGMENsensor specializes in clamp-on technology for CDU cooling, pharmaceutical, food processing, and retrofit applications where the pipe cannot be cut or contamination is unacceptable.
Can a clamp-on ultrasonic flow meter measure a partly filled pipe?
Clamp-on transit-time meters are intended for full-pipe measurement of single, clean, acoustically conductive liquids. A partly filled pipe, gas, steam or two-phase flow is not suitable, so make sure the pipe is full at the measuring point.

Installation and operation

How are the clamp-on sensors mounted on the pipe?
A pair of sensors is fixed to the outside of the pipe with a DT dual-rail bracket for A2, H1A and H2A sensors. The U20 handheld meter also offers an ST single-rail bracket and an SMT D2 bracket. One sensor pair covers DN25–DN1200 pipes; DN15–DN40 pipes use the small-pipe B1 / B1H sensors (F1 / F1H on the U20).
Can the ultrasonic flow meter log data?
The U10 series and U20 accept an SD card up to 32 GB, and the U20 logging interval is adjustable from 1 to 99999 s. The U11 stores data on an expandable Fcard (up to 32 GB). The U12 and U13 use internal EEPROM.
How long does the portable U20 run on one charge?
The U20 handheld ultrasonic flow meter has a rechargeable 3000 mAh lithium battery, about 16 hours of normal use per charge. It measures pipes from 1 in to 48 in (25–1200 mm) at velocities of ±0.01 to ±12 m/s.

Applications and process conditions

Can clamp-on ultrasonic flow meters be used for CDU data center cooling?
Yes — clamp-on suits CDU liquid cooling because it installs without modifying coolant lines and never touches the fluid. The meters measure single, acoustically conductive liquids in a full pipe, such as deionized water; send us your glycol mix for an application check. RS485 Modbus output connects to DCIM platforms for PUE/WUE reporting, and an optional relay output can signal low-flow alarms.
What liquids can be measured?
Single, acoustically conductive liquids in a full pipe. The datasheets list pure water, tap water, seawater, diesel, gasoline, methanol, ethanol and chemical mixtures. U10 is specified for water (a small amount of bubbles is allowed); U12 and U13 for water and other single liquids without solid particles; U11 tolerates intermittent bubbles or impurities lasting up to 5 seconds. Not suitable for gas, steam or two-phase flow.
What temperatures can the clamp-on sensors handle?
On the U10 series and U11, standard clamp-on sensors cover −40 to +80 °C, high-temperature sensors reach +130 °C (H1A) and +180 °C (H2A), and small-pipe sensors (DN15–DN40) cover 0–65 °C or 0–115 °C. On the U20, sensors cover −40 to +80 °C (P2) or +130 °C (P2H). All clamp-on sensors are IP68.
Can the meter be used as a heat or cooling energy meter?
Yes. Every model comes in two transmitter types: F (flow meter) and E (heat / cooling energy meter with PT1000 temperature sensors). On the U12 and U13 the E type displays and measures the medium temperature.

Selection, specifications and quotation

What pipe sizes are compatible with clamp-on ultrasonic flow meters?
SEGMENsensor clamp-on ultrasonic flow meters cover pipes from DN15 to DN5000 depending on the model: U13 compact one-piece DN15–DN40; U12 one-piece DN15–DN65; U10S PRO wall-mount 15–1200 mm; U10 wall-mount 25–1200 mm; U20 handheld 25–1200 mm (1–48 in); U11 high-accuracy wall-mount 15–5000 mm. Pipe materials listed in the datasheets include stainless steel, carbon steel, cast iron, copper, PVC, PP and other rigid plastics.
What is the accuracy of a clamp-on ultrasonic flow meter?
Accuracy depends on the model: U11 ±0.5% (repeatability 0.1%); U10, U10S PRO and U20 ±1% (U10 series repeatability 0.2%); U12 ±2% (±1% after calibration); U13 <3% FS (<1.5% FS after calibration). The meters are intended for full pipes, and the sensors need a straight pipe run upstream and downstream as described in the installation guide.
What output signals are available?
Outputs depend on the model. U10, U10S PRO and U11: choose two of 4–20 mA, pulse (OCT), relay, RS232 Modbus and RS485 Modbus, with HART as an option. U12 and U20: choose two of 4–20 mA, RS485 Modbus, OCT pulse and relay. U13: 4–20 mA and RS485 Modbus, with optional pulse or relay. Outputs are selected in the ordering code.
Which clamp-on model should I choose: portable or fixed?
Use the U20 handheld for spot checks and surveys on pipes of 25–1200 mm. For permanent wall-mount monitoring choose the U10 (25–1200 mm), U10S PRO (15–1200 mm) or the high-accuracy U11 (15–5000 mm, ±0.5%). For small pipes use the compact one-piece U12 (DN15–DN65) or U13 (DN15–DN40).
What certifications do the ultrasonic flow meters have?
The SEGMENsensor clamp-on ultrasonic flow meters carry CE and UKCA marking, as stated on the model datasheets. If your project needs another approval, email info@segmensensor.com.
How do samples, lead time and private-label orders work for OEM ultrasonic flow meters?
Qualification samples of 1–5 units ship in 5–7 days. Production is planned around your annual volume; private-label (custom-branded) versions are quoted by quantity, and production lead time and order quantity are confirmed with the quotation. Quoted FOB China. International freight and import duties/taxes are not included. NDA available on request.
Not sure which model fits your pipe and liquid?
Send the pipe size, material and liquid to an application engineer. OEM volume supply · samples 5–7 days · reply within 24 h.
Talk to an application engineer

Related Articles

How to Install a Clamp-On Flow Meter: Step-by-Step

Get an OEM Clamp-On Flow Meter Quote

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Related Models & Guides

Related Models & Guides

Buy online: six clamp-on models
U10, U10S PRO, U11, U12, U13, U20 · Buy online
U10 wall-mount flow meter
Configure U10 · ±1% · DN25–DN1200
U20 portable flow meter
Handheld clamp-on · 25–1200 mm
U12 wall-mount: installation video
Small-pipe clamp-on · DN15–DN65
U13 compact: installation video
Integrated clamp-on · DN15–DN40
Clamp-on models compared
U10, U11, U12, U13 and U20 side by side
How to install a clamp-on flow meter
Sensor spacing, pipe preparation, coupling
Transit-time vs Doppler
Which principle fits your liquid
Import duty and VAT by country
Landed-cost estimate for flow meters
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Flow Meter Downloads
Datasheets, manuals and CE declarations — on request
info@segmensensor.com