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
  • Compact footprint
  • Robust enclosure, IP66/IP67 rated
  • Pressure rating 100 bar
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Low-Flow Ultrasonic Flow Meters for Liquids

The innovative ES-FLOW® Ultrasonic Liquid Flow Meter/Controller is designed for measuring volume flow ranges between 2 and 1500 ml/min with high precision, high linearity and low pressure drop using Ultrasonic Wave Technology in a small bore tube. Liquids can be measured independent of fluid density, temperature and viscosity, therefore recalibration per fluid is unnecessary. The flow meter has a straight sensor tube design with the actuators positioned at the outer surface. Therefore, the instrument is easy to clean. All wetted parts are made of stainless steel, build in an aluminium housing. The on-board PID controller can be used to drive a control valve or pump, enabling users to establish a complete, compact control loop.

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.

Technical specifications

Measurement / control system
Maximum full scale flow1500 ml/min
Minimum flow2 ml/min
Volume flow accuracy≤ ±0,8% Rd
Repeatability≤ 0,1% Rd ± 0,05 ml/min
Turndown ratiodigital 1:750
(full scale value scalable by the user);
analog: 1:50 (2...100%), also applicable for controller
Zero stability (ZS)≤ 0,4 ml/min
FluidsSpeed of sound between 1000 and 2000 m/s;
fluid independent measurement; also suitable for non-conductive fluids
Response time (sensor)≤ 50 msec (t98%)
Refresh (cycle) time≤ 10 msec
Fluid temperature-10...60 °C
Ambient temperature0...60 °C
Mountingany position, attitude sensitivity negligible
Temperature accuracy±1 °C
Mechanical parts
Sensorstraight 1/16" tube, 1,3 mm ID
Material (wetted parts)stainless steel 316L (1.4404)
Pressure rating (PN)100 bar g
Process connections3 mm, 6 mm, 1/8”, 1/4” OD compression type;
other on request
Ingress protectionIP66 and IP67
Electrical properties
Power supply+15…24 Vdc ±10%
Max. power consumption2,8 W
Analog output0…5 (10) Vdc; 0 (4)…20 mA (sourcing)
Analog setpoint0…5 (10) Vdc, impedance > 100 kΩ;
0 (4)…20 mA, impedance ~250 Ω
Customised I/OAnalog control signal output (option): 0...10 Vdc or 4...20 mA
Pulse output (option)
Digital communicationStandard: RS232;
Options: PROFIBUS DP, DeviceNet™, EtherCAT®, Modbus RTU/ASCII, CANopen®, FLOW-BUS, PROFINET, Modbus/TCP, EtherNet/IP, POWERLINK
Electrical connection
Analog/RS232M12 8-pin connector male
Actuator/Remote displayM8 4-pin connector male
PROFIBUS DPM12 5-pin connector male
CANopen® / DeviceNet™M12 5-pin connector male
FLOW-BUS/Modbus-RTU/ASCIIM12 5-pin 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

Technical specifications subject to change without notice.

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


Datasheet ES-FLOW ES-1xxC
Manual ES-FLOW C-version
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-113C
Solids 3D