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A non-contacting liquid flow velocity sensor that uses microwave technology to determine the velocity.

Non Contact Flow Meter

Key features:

■ Non-contacting
■ Minimal installation
■ RS485 Modbus
■ Maintenance free


The ORAKEL Non-Contact Flow Sensor is a non-contacting liquid flow velocity sensor that uses microwave technology to transmit short pulses that reflect off a moving surface back to the sensor and are analysed to determine the velocity.

How it works

Using radar technology, the Non-Contact Flow Sensor uses a velocity x area calculation to provide a cost-effective flow measurement.

Supplied with a 45° angled mounting bracket for optimum performance, the sensor uses radar technology to measure velocity at single or multiple points, depending on the width of the channel.

The Non-Contact Flow Sensor is available as a stand-alone device or as part of a complete flow measurement system when combined with our level and submerged velocity sensors.



The ORAKEL Non-Contact Flow Sensor is designed for open-channel flow applications where the channel has no existing primary measurement device (e.g.: weir or flume).

The non-contact sensor can be combined with a level transducer and controller in order to provide a complete flow measurement system.

It has an extremely low power consumption, making it suitable for a broad range of wastewater monitoring applications and use in remote installations, where mains power is unavailable.

■ Permanent and portable sewer monitoring programs
■ Wastewater treatment plants
■ Industrial process measurement
■ Irrigation channels
■ Effluent flow measurement
■ Spill monitoring
■ Combined Sewer Overflows (CSO)
■ Sanitary Sewer Overflows (SSO)
■ Event Duration Monitoring (EDM)


Key Features

The sensor can be installed anywhere with a clear, uninterrupted view of the water. It uses microwave technology to transmit short pulses that reflect off a moving surface back to the sensor which are analysed to determine the velocity.

Minimal Installation
It’s lightweight, compact design makes installation simple, especially within confined spaces and requires no interruption to normal operational flow.

RS485 Modbus
Can be installed as a stand-alone velocity sensor, delivering data via RS485 Modbus or integrated with a complete system when combined with a control unit and level transducer.

Equipped with a display screen, readings can be taken directly from the control unit or an optional GSM data-logger can be added and data sent to an online portal for detailed analysis.

Because of the non-contact measurement, the sensor cannot be harmed by sediments and floating debris. The outer enclosure is IP68 rated, meaning it is dust-tight and resistant to water
damage, making it a very low-maintenance sensor.

The control unit includes a full set of instrument and measurement diagnostics tools to simplify installation and maintenance; reducing the need for site visits.

Technical Specificaton

Sensor dimensions: 90 x 140mm.
Sensor weight: 1kg.
Material: Valox 357.
Transducer cable extensions: 5-core screened.
Max separation: Up to 100m.
Mounting connection: via 1″ BSP back-mounted thread or 20mm via supplied adaptor (optional mounting  bracket available).
Mounting angle: 45° optimum and mounted at the centre line of the channel with a clear uninterrupted view.

Enclosure protection: IP68.
Operating temperature: -20°C to +60°C.

CE and radar approved.
ATEX: Ex II 2 G D, Ex mb IIC T4 Gb, Ex mb IIIC.
T135°C Db, Ta= -20°C to +60°C.

Velocity range: 0.2 – 6m/s.
Operational range: up to 3m height.
Accuracy: the greater of ±0.5% or 0.05m/s.
Optimum installation: install at an angle of 45° in-line with flow.
Max channel width: 1.5m.
Radar: K-Band (ISM).
Transmitter power: <15 dBm.
Beam width: 20° inclusive.

Communication: RS485 and Modbus RTU.

PC programming: via RS485 Modbus RTU.
Programming security: via passcode.
Programmed data integrity: via non-volatile memory.

Operating voltage: 10-28Vdc.
Power consumption: 0.36W.
Also available in a 4-20mA loop-powered version with ATEX Ex via Zone 0 approval.

Product Specification

Learn More

Download the latest information about the Orakel and Non Contact Flow Meters.

Datsheets – EN:
MMS D019 – ORAKEL Non Contact flow monitoring system
MMS D017 – ORAKEL control unit

Datenblätter – DE:
MMS D031 – GmbH ORAKEL Non Contact
MMS D029 – GmbH ORAKEL Control Unit

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