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
  • Local display with capacitive touchscreen
  • IP66/IP67 rating
  • Pressure rating 100 bar


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Low-Flow Ultrasonic Flow Meters for Liquids

ES-FLOW® model ES-113I Liquid Flow Meters (LFMs) are suited for precise measurement of volume flow ranges between 2 and 1500 ml/min. 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-113I has orbitally welded compression type connections, making this instrument suitable for operating pressures up to 100 bar.

Bronkhorst® ES-FLOW® series are equipped with advanced electronics, 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.

The second generation of the ES-FLOW series, is indicated by suffix MkII.

ES-FLOW model ES-103I liquid flow meters with Tri-Clamps can be delivered with 3-A certificate. Bronkhorst can also supply the Manufacturer Declaration for EC Regulation Nos. 1935/2004 and 2023/2006 (Food Contact Materials). ES-103I can be combined with a GEMÜ 650 pneumatic diaphragm valve to make it an excellent hygienic flow controller for a wide range of applications within the Food & Beverage market. The GEMÜ valve is also 3-A authorised.

Technical specifications

Measurement / control system
Maximum full scale flow1500 ml/min
Minimum flow2 ml/min
Volume flow accuracyMkI: ≤ ±1% Rd;
MkII: ≤ ±0,8% Rd
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%);
Zero stability (ZS)MkI: ≤ 1 ml/min;
MkII: ≤ 0,4 ml/min
Fluidsliquids with sound speed between 1000 and 2000 m/s;
fluid independent measurement; also suitable for non-conductive fluids
Response time (sensor)50 msec (t98%)
Refresh (cycle) time10 msec
Fluid temperature-10 … 90 °C
Ambient temperature0 … 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)100 bar g
Process connections3 mm, 6 mm, 1/8”, 1/4” OD compression type or 1/4”face seal male (welded)
WeightMeter: 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);
8-pin power: 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)
Control valve options
External actuator options to be connected to the controller
Certification for hazardous areas
Approvals / certificates
Food contactEC 1935/2004

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
ES-FLOW Series DoC EC1935-2004
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