U10 / U10S: ±1% wall-mount meters for 25–1200 mm (U10) or 15–1200 mm (U10S) pipe. U10S PRO: U10S with a colour backlit display. U11: ±0.5% high-accuracy wall-mount meter for 15–5000 mm pipe. U12: one-piece clamp-on meter for DN15–DN65. U13: compact one-piece meter with an acid- and alkali-resistant PP glass-fibre housing for DN10–DN40. U20: battery-powered handheld for 25–1200 mm (1"–48"). Every model is also available as a heat / cooling (BTU) energy meter.
One Measuring Principle, Six Models
Every SEGMENsensor clamp-on flow meter uses the transit-time ultrasonic method. Two sensors clamp to the outside of the pipe and measure the difference in travel time between ultrasonic pulses sent with and against the flow. That time difference is proportional to the average flow velocity, and the meter converts it to flow rate from the pipe outer diameter, wall thickness and material you enter. There is no pipe cutting, no process shutdown and nothing in contact with the liquid.
The models differ in pipe size range, accuracy class, flow velocity range, construction (wall-mount transmitter with separate sensors, one-piece clamp-on body, or handheld), outputs and power supply. All of them are intended for full pipes and a single, clean liquid that conducts sound; the U10 datasheet specifies water with a small amount of bubbles allowed.
Comparison at a Glance
All values below are taken from the current SEGMENsensor datasheets. Use the table as a first-pass filter, then read the model sections for sensors, display and data logging.
| Model | Construction | Pipe size | Accuracy | Flow velocity | Outputs | Power |
|---|---|---|---|---|---|---|
| U10 | Wall-mount transmitter + separate sensors, plastic housing | 25–1200 mm | ±1% | ±0.03 to ±5 m/s | Choose 2: 4–20 mA, pulse (OCT), relay, RS232 / RS485 Modbus; HART optional | 10–36 V DC; 90–245 V AC optional |
| U10S / U10S PRO | Wall-mount transmitter + separate sensors, aluminium housing (PRO: colour display) | 15–1200 mm | ±1% | ±0.03 to ±5 m/s | Choose 2: 4–20 mA, pulse (OCT), relay, RS232 / RS485 Modbus; HART optional | 10–36 V DC; 90–245 V AC optional |
| U11 | Wall-mount transmitter + separate sensors, high accuracy | 15–5000 mm | ±0.5% | ±0.01 to ±12 m/s | Choose 2: 4–20 mA, pulse (OCT), relay, RS232 / RS485 Modbus; HART optional | 90–245 V AC or 10–36 V DC |
| U12 | One-piece clamp-on, metal housing | DN15–DN65 | ±2% (±1% after calibration) | 0.03–10 m/s | Choose 2: 4–20 mA, RS485 Modbus, OCT pulse, relay | 10–24 V DC |
| U13 | Compact one-piece clamp-on, PP glass-fibre housing | DN10–DN40 (OD 12–52 mm) | <3% FS (<1.5% FS after calibration) | 0.15–10 m/s | 4–20 mA and RS485 Modbus; pulse or relay optional | 20–28 V DC |
| U20 | Handheld with clamp-on sensors | 25–1200 mm (1"–48") | ±1% | ±0.01 to ±12 m/s | Choose 2: 4–20 mA, RS485 Modbus, OCT pulse, relay | 3000 mAh rechargeable lithium battery, about 16 h per charge |
U10 — Wall-Mount Meter for Water Pipes from 25 mm
The U10 is the entry model of the range: a wall-mount transmitter in a plastic housing with external keys, connected to separate clamp-on sensors. It measures ±0.03 to ±5 m/s in both directions with ±1% accuracy, 0.2% repeatability and ±1% linearity, on pipes from 25 to 1200 mm. The datasheet medium is water, with a small amount of bubbles allowed.
Any two outputs can be selected from 4–20 mA (maximum load 750 Ω), 0–10 kHz pulse, OCT, relay, RS232 Modbus and RS485 Modbus, with HART as an option. The transmitter runs on 10–36 V DC, or on 90–245 V AC as an option, and is rated IP65; the clamp-on sensors are IP68. An SD card of up to 32 GB can be added for data logging. Standard sensor cable is 9 m, and custom lengths up to 274 m are available (B1 / B1H small-pipe sensors: 5 m standard).
- Water supply, irrigation and cooling-water lines from 25 mm
- Retrofitting flow measurement on pipes that cannot be cut or shut down
- PLC or BMS integration over 4–20 mA or RS485 Modbus
U10S and U10S PRO — Aluminium Housing, from 15 mm
The U10S shares the U10 measurement performance — ±1% accuracy, 0.2% repeatability, ±0.03 to ±5 m/s — but uses an aluminium housing with built-in keys and covers pipes from 15 to 1200 mm. Pipes from DN15 to DN40 use the B1 (0–65 °C) or B1H (0–115 °C) small-pipe sensors; larger pipes use the A2, H1A or H2A clamp-on sensors. The U10S is specified for any single liquid that conducts sound.
The U10S PRO uses the same aluminium housing with external keys and a colour backlit display that stays readable in dark plant rooms. Outputs, power supply (10–36 V DC, 90–245 V AC optional), IP65 transmitter / IP68 sensor ratings and the optional 32 GB SD card are the same as on the U10.
- Small pipes from DN15 where the U10 (from 25 mm) does not fit
- Installations where a metal housing is preferred
- Plant rooms where a colour display is easier to read (U10S PRO)
U11 — High-Accuracy Meter for 15–5000 mm Pipe
The U11 is the high-accuracy industrial model: ±0.5% accuracy, 0.1% repeatability and a flow velocity range of ±0.01 to ±12 m/s on pipes from 15 to 5000 mm. It uses an industrial FPGA chip and SEGMENsensor's TGA time-measurement algorithm, samples up to 300 times per second and tolerates non-continuous bubbles or impurities lasting up to 5 seconds.
Outputs: 4–20 mA (750 Ω), 0–9999 Hz OCT pulse with adjustable upper and lower frequency limits, SPST relay (maximum 1 Hz; 0.4 A at 125 V AC or 2 A at 30 V DC), RS232 Modbus and RS485 Modbus — any two can be selected, with HART as an option. The U11 runs on 90–245 V AC (48–63 Hz) or 10–36 V DC. Data is stored on an Fcard expandable to 32 GB. It uses the same A2, H1A, H2A, B1 / B1H and I1 / I1H sensors as the U10 series; all are IP68.
- Applications that need ±0.5% instead of ±1%
- Large water mains and process pipes above 1200 mm, up to 5000 mm
- Low-velocity lines down to 0.01 m/s
- Liquids with occasional bubbles or impurities
U12 — One-Piece Clamp-On Meter for DN15–DN65
The U12 combines the transmitter and the sensors in one metal clamp-on body with a backlit display, so there is no separate wall-mount enclosure to install. It covers DN15 to DN65 (minimum measurable pipe inner diameter 12 mm) at 0.03–10 m/s with ±2% accuracy, or ±1% after calibration. It is intended for water and other single liquids without solid particles or impurities.
Any two outputs can be selected from 4–20 mA, RS485 Modbus, OCT frequency and one relay; LoRa and 4G can be customised. Power is 10–24 V DC (1 A), the housing is rated IP65, and data is held in EEPROM. The B1 sensor covers liquid temperatures of 0–65 °C and the B1H 0–115 °C. Sensor cable is 2 m as standard, up to 5 m.
| U12 pipe size | DN15 | DN20 | DN25 | DN32 | DN40 | DN50 | DN65 |
|---|---|---|---|---|---|---|---|
| Upper flow limit (L/min) | 60 | 100 | 200 | 300 | 400 | 600 | 1000 |
- Cooling loops, chilled-water branches and equipment skids from DN15 to DN65
- OEM machines that need a compact meter without a separate transmitter
- Small-energy metering with the E (energy) version
U13 — Compact Meter for DN10–DN40 and Tight Spaces
The U13 is the smallest model: a one-piece clamp-on meter in an acid- and alkali-resistant PP glass-fibre housing, designed for small pipes and tight spaces. It covers DN10 to DN40 (pipe outer diameter 12–52 mm) at 0.15–10 m/s with <3% FS accuracy, or <1.5% FS after calibration. A 256×128 backlit LCD shows flow and temperature in real time.
Outputs are 4–20 mA and RS485 Modbus, with an optional OCT pulse or one relay alarm output. Power is 20–28 V DC, the connection is an M12 connector, the low-flow cut-off is 0.08 m/s and the response time can be set from 0.5 to 60 s. The B1 sensor covers −10 to +65 °C and the B1H −10 to +105 °C.
| U13 pipe size | DN10 | DN15 | DN20 | DN25 | DN32 | DN40 |
|---|---|---|---|---|---|---|
| Flow range (L/min) | 0.35–30 | 0.55–60 | 0.95–100 | 1–150 | 1.5–260 | 2.5–400 |
- Pipes from DN10, below the range of the other models
- Tight installation spaces inside machines and cabinets
- Liquid-cooling and dosing lines where a small, non-metallic housing helps
U20 — Handheld Meter for Surveys and Commissioning
The U20 is the portable model for engineers who need to measure at several points without a permanent installation. It covers 1" to 48" (25–1200 mm) pipe at ±0.01 to ±12 m/s (±0.03 to ±40 ft/s) with ±1% accuracy; F1 / F1H sensors are available for DN15–DN40. A rechargeable 3000 mAh lithium battery runs the meter for about 16 hours per charge, and a 240×128 backlit LCD shows the readings.
Readings are logged to an SD card of up to 32 GB at an interval of 1–99999 s. Any two outputs can be selected from 4–20 mA, RS485 Modbus, OCT frequency and relay. P2 sensors cover −40 to +80 °C and P2H sensors up to +130 °C; all sensors are IP68. Sensor cable is 5 m as standard and up to 30 m custom. Mounting rails are supplied for the clamp-on sensors.
- Flow surveys before ordering a permanent meter
- Commissioning and balancing of chilled-water and heating circuits
- Checking existing inline meters in the field
- Energy audits with the E (energy) version
Heat and Cooling Energy (BTU) Versions
Every model is available in two transmitter types: F (flow meter) and E (heat / cooling energy meter). The E version adds matched PT1000 temperature sensors on the supply and return pipes; the meter calculates the heat released or absorbed from the flow rate and the temperature difference. Ultrasonic energy meters are mostly used on water-based heat exchange systems, for both heating and air-conditioning. On U12 and U13, the E version measures and displays the liquid temperature alongside the flow.
Clamp-On Sensors and Temperature Ratings
| Sensor code | Type | Temperature | Used with |
|---|---|---|---|
| A2 | Clamp-on, IP68 | −40 to +80 °C | U10, U10S, U11 |
| H1A | Clamp-on, IP68 | −40 to +130 °C | U10, U10S, U11 |
| H2A | Clamp-on, IP68 | −40 to +180 °C | U10, U10S, U11 |
| B1 / B1H | Clamp-on, IP68, DN15–DN40 | 0 to +65 °C / 0 to +115 °C | U10, U10S, U11 |
| I1 / I1H | Insertion, IP68 | −40 to +130 °C / −40 to +180 °C | U10, U10S, U11 (U20: I1 only) |
| P2 / P2H | Clamp-on, IP68 | −40 to +80 °C / −40 to +130 °C | U20 |
| F1 / F1H | Clamp-on, IP68, DN15–DN40 | 0 to +65 °C / 0 to +115 °C | U20 |
| U12 B1 / B1H | Integrated | 0 to 65 °C / 0 to 115 °C | U12 |
| U13 B1 / B1H | Integrated | −10 to 65 °C / −10 to 105 °C | U13 |
A2, H1A and H2A sensors mount on the DT double-rail fixture. Certifications for the whole flow meter range are CE and UKCA.
Model Selection Guide
Start with pipe size and required accuracy, then check power supply and outputs. If two models qualify, the tie-breaker is usually construction (one-piece vs wall-mount) or whether the meter must be portable.
| Your requirement | Recommended model |
|---|---|
| Pipe DN10–DN40, tight space, 20–28 V DC available | U13 |
| Pipe DN15–DN65, one compact unit, 10–24 V DC | U12 |
| Permanent installation, 25–1200 mm, ±1% | U10 |
| Permanent installation, 15–1200 mm, ±1%, aluminium housing | U10S (colour display: U10S PRO) |
| ±0.5% accuracy, flow down to 0.01 m/s, or pipe above 1200 mm (to 5000 mm) | U11 |
| Pipe surface above +80 °C on a wall-mount meter | U10 / U10S / U11 with H1A (+130 °C) or H2A (+180 °C) sensors |
| Portable survey, commissioning or meter verification | U20 |
| Heating or cooling energy (BTU) metering | Any model in the E (energy) version with PT1000 sensors |
For OEM projects that need private labelling or a specific configuration, contact the SEGMENsensor OEM engineering team with your pipe size, liquid, temperature and required outputs. Installation steps are covered in how to install a clamp-on flow meter, and the measuring principle in transit-time vs Doppler ultrasonic flow meters.
Frequently Asked Questions
The U11 is the high-accuracy model: ±0.5% accuracy with 0.1% repeatability, a flow velocity range of ±0.01 to ±12 m/s and pipe sizes from 15 to 5000 mm. U10, U10S, U10S PRO and the U20 handheld are specified at ±1% with 0.2% repeatability on the U10 series. U12 is ±2% (±1% after calibration) and U13 is <3% FS (<1.5% FS after calibration).
All three are wall-mount transmitters with separate clamp-on sensors, ±1% accuracy, ±0.03 to ±5 m/s flow velocity and 10–36 V DC power (90–245 V AC optional). U10 has a plastic housing with external keys and covers 25–1200 mm pipe. U10S has an aluminium housing with built-in keys and covers 15–1200 mm. U10S PRO uses the aluminium housing with a colour backlit display and external keys.
For DN10 to DN40 choose the U13 compact one-piece meter (pipe outer diameter 12–52 mm). For DN15 to DN65 choose the U12 one-piece meter. U10S and U11 also start at 15 mm when fitted with the B1 or B1H small-pipe sensors for DN15–DN40, and the U20 handheld uses F1 or F1H sensors for DN15–DN40.
It depends on the sensor. On U10, U10S and U11 the standard A2 clamp-on sensor is rated −40 to +80 °C, H1A to +130 °C and H2A to +180 °C; the B1 / B1H small-pipe sensors are rated 0–65 °C or 0–115 °C. The U20 handheld uses P2 sensors (−40 to +80 °C) or P2H sensors (to +130 °C). U12 sensors are rated 0–65 °C or 0–115 °C, and U13 sensors −10 to +65 °C or −10 to +105 °C.
U10, U10S 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 an optional pulse or relay output.
Yes. Every model is available as a heat / cooling (BTU) energy meter. The energy version adds PT1000 temperature sensors on the supply and return pipes, and the meter calculates the energy released or absorbed from the flow rate and the temperature difference.
As a general installation rule, allow at least 10 pipe diameters (10D) of straight pipe upstream and 5D downstream of the sensors, away from elbows, tees, valves, reducers and pumps. On a DN100 pipe this means about 1,000 mm upstream and 500 mm downstream. Allow more upstream distance after a control valve or pump.
In V-mode both sensors sit on the same side of the pipe and the signal reflects off the far wall, which suits most small and medium pipes. In Z-mode the sensors sit on opposite sides so the signal crosses the pipe once; use it on large pipes, scaled or lined pipes, or whenever the V-mode signal strength stays low.