Portable Clamp-On Ultrasonic Flow Meter — Battery Powered, 25–1200 mm, OEM China
The SEGMENsensor U20 handheld clamp-on ultrasonic flow meter measures liquid flow without pipe cutting or process shutdown. Clamp the transducers onto the outside of the pipe — transit-time measurement gives ±1% accuracy on full pipes of clean, sound-conducting liquids. Pipe range 1" to 48" (25–1200 mm), velocity ±0.01 to ±12 m/s. SD card logging up to 32 GB, two outputs of your choice (4–20 mA, RS485 Modbus, OCT pulse, relay), and a 3000 mAh rechargeable battery for about 16 hours per charge. CE and UKCA. OEM from Shenzhen since 2019, OEM volume supply.
OEM volume supply · Samples 5–7 days · Quote reply within 24 h · FOB China · import duty by country
Key facts
The SEGMENsensor U20 is a battery-powered handheld ultrasonic flow meter that measures liquid flow by clamping transit-time transducers onto the outside of a pipe, with no cutting, no shutdown and no contact with the liquid. It covers 1" to 48" (25–1200 mm) pipes and logs readings for surveys, commissioning and meter checks.
Pipe range is 1" to 48" (25–1200 mm); velocity range is ±0.01 to ±12 m/s.
Accuracy is ±1% on full pipes of single-phase, sound-conducting liquids.
Readings log to an SD card of up to 32 GB, at an interval of 1 to 99999 seconds.
The 3000 mAh rechargeable lithium battery lasts about 16 hours per charge.
Outputs: choose two of 4–20 mA, RS485 Modbus, OCT pulse and relay; sensors are IP68; CE and UKCA; qualification samples are 1–5 pcs.
Last updated · SEGMENsensor Engineering Team
Watch: installation guide and U20 setup
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.
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.
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.
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.
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.
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.
Tested on our water flow test line
Water flow test line for ultrasonic flow metersClamp-on flow meter checked on the test line
Every unit is tested before shipment. Photos from our own production and test lines.
What is a Portable Clamp-On Ultrasonic Flow Meter?
A portable clamp-on ultrasonic flow meter is a handheld, battery-powered instrument that measures liquid flow by clamping ultrasonic transducers onto the outside of a pipe. No pipe cutting, no process shutdown, and no contamination risk. It uses the transit-time method: two ultrasonic pulses travel diagonally through the pipe, one with the flow and one against. The time difference between the two pulses is proportional to the average flow velocity. Multiplied by the pipe cross-sectional area, this gives volumetric flow rate. Ideal for commissioning verification, energy audits, spot-checks, and rental applications.
Specifications
Portable Clamp-On Ultrasonic Flow Meter — Full Specification Table
Transit-time measurement principle. Specifications of the U20 handheld meter as listed in its datasheet. High-temperature P2H sensors (up to +130 °C) available.
Parameter
Value
Model
U20 handheld (portable) clamp-on ultrasonic flow meter
Measurement Principle
Transit-time (ultrasonic)
Pipe Size Range
1" to 48" (25–1200 mm)
Pipe Material
Metal, plastic and composite pipes that conduct ultrasound (metal, plastic or composite)
Liquid
Single-phase, sound-conducting liquid; full pipe, high cleanliness
Accuracy
±1%
Velocity Range
±0.01 to ±12 m/s (±0.03 to ±40 ft/s)
Output
Choose two of: 4–20 mA, RS485 Modbus, OCT (pulse / frequency), 1 relay
Display
240×128 LCD with backlight
Data Logging
SD card up to 32 GB; logging interval 1–99999 s
Power
Rechargeable lithium battery, 3000 mAh; about 16 hours per full charge under normal use
Clamp-On Sensors
P2: IP68, −40 to +80 °C · P2H: IP68, −40 to +130 °C · F1: IP68, 2 MHz, DN15–DN40, 0 to +65 °C · F1H: IP68, 2 MHz, DN15–DN40, 0 to +115 °C
Insertion Sensor
I1: IP68, −40 to +130 °C
Sensor Cable
Standard 5 m, custom length up to 30 m; F1 / F1H: standard 3 m, custom up to 5 m
Versions
F: ultrasonic flow meter · E: ultrasonic heat / cooling (BTU) energy meter with PT1000 clamp-on temperature sensors (9 m cable)
Mounting Accessories
ST single rail, DT dual rail, SMT D2 bracket
Protection
IP68 (sensors)
Certifications
CE, UKCA
Samples
Samples 1–5 pcs for qualification; volume per project
Lead Time
Confirmed with the quotation (standard production); samples 1–5 pcs in 5–7 days; custom OEM confirmed at order
Download the clamp-on ultrasonic flow meter datasheet (PDF)
Pipe size range, velocity range and accuracy, transducer types, outputs and data logging, supply, sensor protection rating and ordering information. No registration required.
How to Install a Portable Clamp-On Flow Meter — 3 Steps
No pipe cutting, no special tools, no process shutdown. From unboxing to a live flow reading in minutes.
01
Input Pipe Parameters
Enter pipe outer diameter, wall thickness, pipe material, and liquid type into the meter. The meter automatically calculates the correct transducer spacing.
02
Mount the Transducers
Clean the pipe outer surface, apply acoustic coupling gel, and secure the transducers at the meter-calculated spacing. Use the mounting rail to hold them in place, then adjust position to maximize signal strength and quality.
03
Start Measurement
The meter displays real-time flow velocity, volumetric flow rate, and accumulated total. Connect the 4–20 mA output to a recorder or read data via RS485 Modbus (two outputs of your choice). Log readings to the SD card (up to 32 GB) at an interval of 1 to 99999 seconds.
Applications
Portable Clamp-On Flow Meter — 8 Industry Applications
From HVAC energy audits to oil field water injection verification — battery-powered portable measurement without pipe modification.
🏢
Building Energy Audits
Measure chilled water and hot water flow in HVAC systems for an energy efficiency baseline. The E version adds PT1000 temperature sensors to measure heating or cooling energy. No system shutdown required.
💧
Water Network Leak Detection
Spot-check municipal water pipe flow balance to identify losses. Portable measurement at multiple nodes to locate unaccounted-for water in distribution networks.
🔧
Industrial Commissioning
Verify pump flow rates and balance cooling circuits during plant startup. Confirm that installed fixed flowmeters are reading accurately against an independent reference.
🖥️
Data Center Cooling (CDU)
Non-invasive measurement of coolant loop flow in CDU systems without process shutdown. Verify coolant distribution balance across server rack manifolds.
⚗️
Chemical Plant Maintenance
Flow verification without chemical exposure — transducers mount on pipe exterior only, eliminating wetted parts and contamination risk in aggressive chemical environments.
🌊
Wastewater Treatment
Measure treated effluent and process water flow in full pipes up to 1200 mm. Transit-time measurement needs a clean, single-phase liquid — not suited to raw sewage or sludge.
🛢️
Oil & Gas Production
Portable oil field water injection flow verification and test separator measurement. Battery operation eliminates need for power supply at remote wellhead locations.
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Rental / Spot Testing
Temporary installation for flow testing, acceptance testing, or dispute measurement. Multi-point survey capability — one meter can cover dozens of measurement points in a single day.
Selection
Which Portable Flow Meter Setup Fits Your Survey?
A portable flow meter is chosen by the job, not only by pipe size. The table matches common field tasks to the U20 version, clamp-on sensor and output or logging setup, using the U20 datasheet values on this page.
U20 portable flow meter: use case to configuration
Field task
Pipe and liquid
U20 version and sensor
Output / logging
HVAC chilled / hot water balancing
Full water pipes, 25–1200 mm
F (flow); P2 sensors, −40 to +80 °C
SD card, 1–99999 s interval
Heating or cooling energy audit
Supply and return water loops
E (energy) with two PT1000 clamp-on temperature sensors, 9 m cable
SD card log of flow and energy
Hot process water or condensate return
Full pipe, liquid up to +130 °C
F; P2H high-temperature sensors, −40 to +130 °C
SD card; 4–20 mA to a recorder
Checking an installed fixed flow meter
Same pipe as the fixed meter, clean single-phase liquid
F; P2 or P2H by temperature
Two outputs from 4–20 mA, RS485 Modbus, OCT pulse, relay
Multi-point water network survey
Distribution mains up to 48" (1200 mm)
F; P2 sensors, IP68
Battery about 16 h per charge; SD card up to 32 GB
The U20 portable flow meter kit: handheld unit, a pair of clamp-on transducers, mounting fixtures and couplant.
How does a portable flow meter measure without cutting the pipe?
Two transducers on the outside of the pipe send ultrasonic pulses with and against the flow. The pulse travelling with the flow arrives slightly sooner, and the time difference is proportional to the average flow velocity; multiplied by the inner pipe area, it gives the flow rate. Because the method relies on sound passing through the liquid, the pipe must be full and the liquid clean and single-phase. For a full comparison with the Doppler method, see transit-time vs Doppler ultrasonic flow meters.
V-mode mounting: both transducers on one side of the pipe, spacing calculated by the meter from the pipe data.
What should you prepare before a portable flow survey?
The real pipe outer diameter, wall thickness and pipe material, measured on site rather than taken from nominal sizes.
A straight run of about 10 D upstream and 5 D downstream of the sensors, away from pumps, valves and elbows.
Liquid type and temperature, to choose P2 (up to +80 °C) or P2H (up to +130 °C) sensors.
A charged battery and an SD card, with the logging interval set before the survey starts.
Send us your pipe size, material, liquid and temperature. We confirm the U20 version and sensors and reply within 24 hours. OEM volume supply; samples ship in 5–7 days.
Both use the same transit-time measurement principle and clamp-on transducers — the difference is power source, installation type, and intended use case.
Feature
Portable Meter
Fixed Installation Meter
Power Source
3000 mAh rechargeable lithium battery (about 16 h)
10–36 V DC, optional 90–245 V AC
Installation
Temporary, multi-point
Permanent, one location
Output
Choose two: 4–20 mA, RS485 Modbus, OCT pulse, relay
SEGMENsensor supplies the U20 portable handheld meter (25–1200 mm) and permanently installed wall-mount clamp-on flow meters covering 15–5000 mm depending on the model. Prices are quoted by specification and quantity, with a reply within 24 working hours. See the full ultrasonic flow meter range.
Technical and sourcing questions from OEM buyers about portable clamp-on ultrasonic flow meters.
How accurate is a portable clamp-on ultrasonic flow meter?
The SEGMENsensor U20 is rated at ±1% accuracy, with a velocity range of ±0.01 to ±12 m/s. The accuracy you achieve on site depends on the installation: a full pipe, a sufficient straight pipe run (as a general rule, about 10 D upstream and 5 D downstream of the sensors), a clean single-phase liquid, good acoustic coupling and a signal strength above 60% on the status screen. Pipe scale or internal coating, entrained gas bubbles and turbulent flow near pumps or elbows all reduce accuracy. Check signal strength and quality on the status screen before recording measurements.
What pipe materials can a clamp-on flow meter measure?
Transit-time clamp-on meters work on metal, plastic and composite pipes that conduct ultrasound. Severely corroded or heavily scaled internal walls scatter the signal, and external insulation must be removed where the sensors are mounted. For lined pipes, confirm signal quality before recording measurements.
What liquid types can be measured with a portable clamp-on flow meter?
The U20 is designed for full-pipe measurement of single-phase, sound-conducting liquids with high cleanliness: for example water, oil and clean chemical solutions. It is not suitable for slurries, liquids with heavy suspended solids, or aerated liquids with significant gas content.
What is the minimum and maximum pipe size for a portable clamp-on flow meter?
The U20 covers pipes from 1" to 48" (25–1200 mm). The standard clamp-on sensors are P2 (IP68, −40 to +80 °C) and P2H (IP68, −40 to +130 °C). After you enter the pipe outer diameter, wall thickness, pipe material and liquid type, the meter calculates the transducer spacing for you.
How long does the battery last?
The U20 runs on a rechargeable 3000 mAh lithium battery. Under normal use, one full charge lasts about 16 hours, enough for a full day of survey or commissioning measurements without a power supply on site.
Can the portable flow meter store and export data?
Yes. The U20 logs measurements to an SD card of up to 32 GB, with the logging interval settable from 1 to 99999 seconds. For a live connection to a recorder, PLC or SCADA system, choose two outputs from 4–20 mA, RS485 Modbus, OCT pulse and relay.
Is the portable flow meter available as a heat and cooling energy meter?
Yes. Besides the flow meter version (F), the U20 is available as an ultrasonic heat / cooling energy meter (E). Two matched PT1000 clamp-on temperature sensors are mounted on the supply and return pipes (9 m cable). The meter calculates the temperature difference and combines it with the measured flow to give the heating or cooling energy delivered by water-based HVAC and process loops.
What is the OEM MOQ and lead time for portable clamp-on flow meters from China?
OEM volume supply for the standard U20 portable clamp-on meter (transit-time, 25–1200 mm pipe range, two outputs of your choice, SD card logging). Samples 1–5 pcs ship in 5–7 days. Production lead time: confirmed with the quotation. Custom OEM configurations (private label, custom color, firmware branding, output selection, sensor type and cable length): quoted by quantity, OEM volume supply. The U20 is CE and UKCA marked. Factory: SEGMEN (Shenzhen) Industrial Development Co., Ltd., Registration No. 91440300MAEUXXQU04, Shenzhen, Guangdong, China.
What is a portable flow meter used for?
A portable flow meter is used for temporary measurements: HVAC balancing and energy audits, commissioning of pumps and cooling circuits, checking an installed fixed flow meter, and surveys at many points in a water network. The U20 clamps onto the outside of 25–1200 mm pipes, runs about 16 hours on its battery and logs readings to an SD card, so one meter can cover several sites.
Which sensor should I choose for hot water pipes?
Choose P2H sensors for liquid temperatures above +80 °C. P2H sensors are rated −40 to +130 °C and IP68; the standard P2 sensors are rated −40 to +80 °C and IP68. Above +130 °C the U20 clamp-on sensors are not suitable.
How long can the U20 log data on one survey?
The logging duration depends on the battery and the SD card. One full charge of the 3000 mAh battery lasts about 16 hours. The SD card holds up to 32 GB, and the logging interval can be set from 1 to 99999 seconds, so a longer interval stretches the same card over a longer survey.
What affects the quote for a portable clamp-on flow meter?
The quote depends on the version (flow F or energy E), sensor type (P2 or P2H), the two selected outputs, cable length, private-label or firmware branding, and order quantity. We quote within 24 hours on working days. Quotes are FOB China; payment is 100% T/T in advance, and the warranty is 12 months.
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