Chandak Instruments Pvt. Ltd.

The Flow Measurement Solution Provider

Flare Gas Meter

Field computer & ultrasonic transducers

Fluenta Flare Gas Meter
The Fluenta FGM 160 has been developed to measure flare gas in pipes where pressure, a wide range of velocity and large pipe diameters represent a challenge. Fluenta offers world-class flare gas meters characterized by:

  • Optimized signal processing and acoustic sensors enabling flow measurement up to 100 m/s
  • Automatic Gain Control (AGC) for enhanced performance
  • Digital Signal Processing (DSP)
  • Software based user interface (Operator Console)
  • Easy and fast to install
  • Field mounted flow computer
  • Low maintenance costs
  • Serial interface based on Modbus protocol


  • Widest velocity range on the market
  • Wetted non intrusive sensor design for all pipe sizes
  • High measurement accuracy throughout entire range
  • Unique signal processing ensures high accuracy at low flow rate
  • Fast response time
  • Certified for operation in hazardous areas
  • No calibration required after installation
  • Rapid installation gives reduced costs
  • Low maintenance
  • High reliability


  • Measurement of flare and vent gas, characterized by a large velocity range, low pressure and large pipe diameters
  • Flare gas density calculation for gas composition indications
  • Leak detection and loss calculation for mass balance in process plants
  • Accurate measurement of very low flow rates in flare and vent systems.


Fluenta’s FGM 160 has specially designed jigs for fast, economical and accurate mounting of transducer holders. These holders are welded onto the pipeline at an angle suitable for each different pipe size. The meter can either be delivered as a hot/cold tap version or with a prefabricated spool piece.

Operating principle

The Fluenta FGM 160 measures gas velocity based on the time–of–flight technique. The ultrasonic transducers are mounted at an angle to the pipe. Both transducers transmit and receive pulses and the transit time is measured. When the gas is flowing in the pipe, the pulses travelling against the flow take longer to reach the opposite transducer than the pulse travelling with the flow. This time difference is used to calculate the velocity of the flowing medium.


Field Computer

Power input: +24 VDC (18 – 36 VDC or 110 – 240 VAC 50/60 Hz, safe area power supply optional)
Consumption: 12 W maximum
Power / instrument cable : Standard twisted pair: RFOU(i)2-3 x 2 x 0.75mm2
Dimensions: 460 x 280 x 250mm (H x W x D)
Weight: 17 kg
Input signals: Signal from transducers via std instrument cable
Temperature & Pressure: 4-20 mA or HART interface
Output: 3 x 4-20 mA analog output channels, with selectable parameters. RS 422/485 Serial Port based on Modbus protocol
Optional output: Additional 3 x 4-20 mA channels
Pulse/frequency signal
Electrical classification: Explosion proof
Ex de (ia) II C T5-T6
Ex d optional
Integrated Barriers
Ingressive Protection: IP 66

System performance
and characteristics

Pipe size: 6” and larger (smaller pipe sizes available on request)
Velocity range: 0,03 – 100 m/s (0.1 – 328 ft/s)
Uncertainty at 95% confidence level (fully developed flow): ±2,5 – 5% of measured value for Qv
Resolution: 0.0008 m/s
Repeatability: Better than 1%
Turndown rangeability: 3330 : 1
Operation temperature: -110 °C - +150 °C (transducers)
-40 °C - +85 °C (electronics)
-50 °C - +60 °C ambient temp
Operating pressure: 0.8 – 10 Bar a
Design temperature: -150 °C - +315 °C (transducers)
Design pressure: 20 Bar a (transducers)

Ultrasonic Transducers

The Fluenta FGM 160 ultrasonic transducers are wetted but non-intrusive. The advantage of this is that the intrusive sensors are more exposed to deposits and particles in the flow. In addition, high flow velocity may cause vibration of the sensors. Such vibration can, over a period of time, lead to a reduced performance of the sensors.

Material: SS316/Titanium
Safety class: Ex ia II C T6 intrinsically safe (Zone 0)

Operator Console

  • Trend curves of all relevant measured and calculated values
  • Full access to all parameters
  • Log of historical measurements
  • Reconfiguration and SW upload to field computer
  • Integrated service console
  • TCP/IP interface option for remote diagnostics and control.

For installation on

  • control room computer
  • service computer
  • remote computers