Ultraflux UF831CO River flow velocity meter

The UF831CO open channel / river flow velocity meter measures the velocity of a fluid in a river or open channel with ultrasound to accurately calculate the flow rate. It incorporates transit time ultrasonic velocity measurements with level measurements to calculate the flow. All the intelligence, innovation and experience acquired by Ultraflux in 40 years of being the world’s specialists and technical experts in ultrasonic transit time measurements is incorporated into this river flow velocity meter.
Submerged velocity sensors are mounted on both banks in a channel or river to measure the flow velocity. These sensors continuously emit a bi-directional ultrasonic pulse and measure the time difference in transit speed from one side to the other. The difference in transit speed is directly proportional to the velocity. Flow rate is easily calculated when the depth is measured to calculate the area of the channel. Having multiple pairs of velocity sensors stacked at different elevations increases the accuracy of the velocity measurement.

Features and benefits

Ability to measure channel widths up to 30 meters or river widths up to 500 metres. This bi-directional river flow velocity meter measures velocity in channels without the need to construct a weir. It is configurable for a wide range of liquids and flow rates.

Eight chord input enables this river flow velocity meter to receive signals simultaneously from eight pairs of sensors. It provides an option to use this river flow velocity meter on up to 4 different rivers or channels. Multiple chords are often used on the same river to obtain more precision in the velocity measurement by capturing velocities at different depths.

Rail probe mounting system to reduce installation time, increase precision and improve accessibility to the probes during maintenance.

Unrivaled performance accuracy with velocity measurement accuracy of +/- 0.5%, measurement resolution approximately 0.1 nano second, repeatability up to 0.1%, linearity up to 0.1% and typical uncertainty on flow rate calculation from 0.5 to 5% depending on application and number of chords.

A function engine with PLC intelligence to totalise flow, perform temperature compensation and more….

Rugged stainless steel enclosure with a high ingress protection rating of IP67 ensures this river flow velocity meter is able to withstand harsh environmental conditions. The back-lit display, keypad and mounting bracket facilitate quick and easy installation and setup. An ingress protection cap is provided for the USB interface.

Signal quality index using echo visualisation to verify the signal quality from each chord and identify any distortions. The outcome of corrective actions are also verified advising the operator the problem has been solved.

Connectivity with current, voltage and temperature inputs. Current, voltage, relay and pulsed outputs and MODBUS communication via a RS232, RS485 or USB serial link, this river flow velocity meter is perfect for integration with instrument control panels and telemetry systems. FIELD bus protocol is available as an alternative option.

Internal data logger with a massive memory storing 530,000 time and date stamped readings over 12 months data at 1 minute logging intervals. The logging interval is user programmable from 1 second to 24 hours . The logger can store a wide range of parameters including min flow, max flow, average flow, velocity, totalised flow and status. It provides an extensive summary of the flow conditions allowing the operator confidence in the data. With the choice of “cyclic” or “stop when the memory is full”, this river flow velocity meter is perfect for storing data that can be retrieved for an incident investigation.

Pulse echo display shows the measurement echo for each chord. This facilitates measurement quality analysis as a useful setup and fault diagnosis tool. The feature may be used during the positioning and alignment of the sensors, assessing the adjustment of settings and to determine when sensors may require cleaning.

Status indicator LED’s on the front panel enabling the operator to quickly evaluate the current status or nature of a problem.

Ability to operate with low voltage, this river flow velocity meter can be powered with renewable energy sources like solar with a backup battery. Power supply required is 9 – 36 Volts DC or 110 V – 240 V AC.

Surge protection to protect the electronics from an increase in power supply. Over voltage protection in accordance with EN 61000-4-5.


  • Waste water: flow measurement at treatment works inlets/outfalls (small channels)
  • Multiple channels or rivers with one device.
  • Raw water: flow measurement in irrigation channels.
  • River flow measurement.
  • When obstruction to river flow impacts flood risk, fish or platypus passage.
  • Water resource management.
  • Effluent discharge measurement.
  • Hydroelectric power generation.