Low-Flow Ultrasonic Flow Meter for Liquids

  • Fast and accurate measuring signal
  • Low pressure loss due to straight sensor tube
  • Medium independent and temperature insensitive
  • Hygienic design, display with capacitive touchscreen
  • IP66/IP67 rating and CIP cleanable
  • Flanged connection


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Low-Flow Ultrasonic Flow Meters for Liquids

ES-FLOW™ model ES-103I Liquid Flow Meters (LFMs) are suited for precise measurement of volume flow ranges between 2 and 1500 ml/min at operating pressures up to 10 bar. The LFM consists of a innovative ultrasonic flow sensor and an IP66/IP67 protected measuring head with bright LCD display and capacitive touchscreen for adjustment of the settings e.g. for flow indication, alarm, totalisation and control (if applicable). The electronics include a PID controller for optional flow control by means of a separately mounted control valve or pump. ES-FLOW™ model ES-103I has orbitally welded TriClamp flanges for hygienic applications.

Bronkhorst® ES-FLOW™ series are equipped with a digital pc-board, offering high accuracy, excellent temperature stability and fast response. The main digital pc-board contains all of the general functions needed for measurement and control. In addition to the standard RS232 output the instruments also offer analog I/O. As an option, an on-board interface can be mounted to provide CANopen®, DeviceNet™, EtherCAT®, PROFIBUS DP, PROFINET, Modbus RTU, ASCII or TCP/IP, EtherNet/IP, POWERLINK or FLOW-BUS protocols.

November 2020, launch of ES-FLOW MkII generation

With the introduction of the second generation of our ES-FLOW series, indicated by suffix MkII, Bronkhorst realised some important improvements and new options. Here are the main MkII-highlights:

  • Hygienic Standards 3-A                                                                                                                  
    The ES-103I MkII with Tri-Clamp flanges is authorized by 3-A, meeting the highest hygienic standards.
  • Hygienic Flow Controller
    Combining the ES-FLOW flow meter with a GEMÜ 650 pneumatic diaphragm valve makes an excellent hygienic flow controller for a wide range of applications within the Food & Beverage market. The GEMÜ valve is also 3-A authorized.
  • EC Regulation Nos. 1935/2004 and 2023/2006 (Food Contact Materials)
    By meeting the requirements, Bronkhorst can provide a Manufacturer Declaration for these regulations.
  • Improved accuracy and rangeability
  • Additional functionalities and EtherNet fieldbus options 

Technical specifications

Measurement / control system
Minimum full scale flowMkI: 200 ml/min;
MkII: 100 ml/min
Maximum full scale flow1500 ml/min
Minimum flow2 ml/min
Volume flow accuracyMkI: ≤ ±1% Rd ± ≤ 1 ml/min;
MkII: ≤ ±0,8% Rd ± ≤ 0,4 ml/min
Repeatability≤ 0,1% Rd ± 0,05 ml/min
Turndown ratiodigital 2:100 up to 2:1500 ml/min (full scale value scalable by the user);
analog: 1:50 (2…100%);
Fluidsliquids with sound speed between 1000 and 2000 m/s;
​fluid independent measurement; also suitable for non-conductive fluids
Response time (sensor)200 msec (meter, t98%)
Refresh (cycle) time10 msec
Fluid temperature max-10 … 90 °C
Ambient temperature max10 … 60 °C
MountingAny position, attitude sensitivity negligible.
Temperature accuracy± 1 °C
Mechanical parts
SensorStraight tube, 1,3 mm ID
Material (wetted parts)stainless steel 316L
Surface qualityRa < 0,8 μm
Pressure rating (PN)10 bara at TAMB = 15…35°C, |TAMB - TMED| ≤ 25°C;
for elevated temperatures please consult factory
Process connections1/4” Triclamp flanges, DIN32676-C (welded);
other on request
Weight Meter: 1,3 kg;
Controller: on request
Ingress protectionIP66 and IP67
Electrical properties
Power supply+ 15 … 24 Vdc
Max. power consumption2.8 W
Analog output0…5 (10) Vdc, min. load impedance > 2 kΩ;
0 (4)…20 mA (sourcing), max. load impedance < 375 Ω
Analog setpoint0…5 (10) Vdc, impedance > 100 kΩ;
0 (4)…20 mA, impedance ~100 Ω
Customised I/OAnalog control signal output: 0…10 Vdc or 4…20 mA;
Pulse output;
for more options, see Model number identification in our ES-FLOW brochure
Digital communicationStandard RS232;
Options: CANopen®, DeviceNet™, EtherCAT®, PROFIBUS DP, PROFINET, Modbus RTU, ASCII or TCP/IP, EtherNet/IP, POWERLINK or FLOW-BUS
Electrical connection
Analog/RS2328-pin M12 connector (male)
Configured I/O / Actuator output8-pin M12 Connector (male)
Actuator/Remote display4-pin M8 connector (female)
PROFIBUS DPbus: 5-pin M12 connector (female);
power: 8-pin M12 connector (male)
CANopen® / DeviceNet™5-pin M12 connector (male)
FLOW-BUS/Modbus-RTU/ASCII5-pin M12 connector (male)
Modbus TCP / EtherNet/IP / POWERLINK2 x 4-pin M12 connector female (in/out)
EtherCAT®/ PROFINET2 x 4-pin M12 connector female (in/out)
PROFINET8-pin M12 connector (male)
Control valve options
External actuator options to be connected to the controller
Ex-proof specifications
Approvals / certificates
Food contactEC 1935/2004;
3-A Sanitary standard on F-103I MkII

Technical specifications subject to change without notice.

For dimensional drawings and hook-up diagrams please visit the product page on our website


ES-FLOW brochure
ES-FLOW model key
Manual ES-FLOW I-version
Quick Installation Guide ES-FLOW with GEMÜ valve
ES-FLOW Series DoC EC1935-2004
3-A Authorization Certificate
Hook-up diagrams
Analog IO - RS232
Industrial EtherNet - MkII (EtherCAT, EtherNet-IP, Modbus-TCP, Powerlink, Profinet)
Optional Bus and IO-Configurations
Dimensional drawing
Dimensional drawing ES-103I-ES-113I MkI
Dimensional drawing ES-103I-ES-113I MkII
Solids 3D


1 Kings Court
Willie Snaith Road
Newmarket Suffolk CB8 7TG
Tel. +44 1223 833222
[email protected]

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