SONARtrac® Volumetric Flow and Entrained Air Measurement System Model VF/GVF-100

CiDRA’s SONARtrac Volumetric Flow and Entrained Air Measurement System is a breakthrough in process measurement technology. The SONARtrac clamp-on, non-contact system allows for on-line real-time measurement of the volumetric flow in difficult to measure slurries and fluids; and the amount of entrained air present in any liquid-continuous-phase process flow. The system also provides a measurement of only the liquid portion of the flow by compensating for the amount of entrained air in the process line.

SONARtrac measurement systems do not utilize ultrasonics; they employ patented sonar array processing techniques to listen to, and interpret, flow turbulence and sound fields generated by the machinery, piping and process flow. This passive listening approach results in measurement of the flow rate and amount of entrained air with a high degree of accuracy and repeatability.

Passive Sonar Technology

CiDRA’s SONARtrac technology represents an innovative new class of industrial measurement instrumentation. This sonar technology utilizes array processing techniques similar to those used in the field of sonar processing. CiDRA’s patented sonar technology was initially developed for flow and compositional measurement in one of the world's most demanding environments: downhole, offshore oil and gas production. CiDRA has taken the proven reliability of its SONARtrac technology to provide new measurement capabilities and provide insight into the monitoring and optimization of homogeneous slurries in many industrial processes.

The SONARtrac Volumetric Flow and Entrained Air Measurement System utilizes an array of sensors that are wrapped around the pipe. The flow rate and percent of entrained air by volume is determined using CIDRA’s array processing techniques and are available as meter outputs. Liquid flow rate is measured by analyzing the flow turbulence in the process stream, while the sound field is used to determine the sound speed, or velocity at which sound propagates, through the process medium. The entrained air percentage is then calculated directly from the measured sound speed.

CiDRA’s clamp-on, non-contact SONARtrac VF/GVF-100 system enables users to realize the following measurable benefits:

  • Increased measurement accuracy and certainty
  • Low installation and life cycle costs
  • Increased process efficiency and uptime
  • Lower maintenance and operating costs


  • Entrained air measurement enables correction of errors in density meters caused by bubbly flows thereby providing a tighter mass balance
  • Volumetric flow measurement of liquid continuous phase process flows
  • Entrained air measurement resulting in ability to monitor and/or assess effect of process disruptions
  • Measurement of entrained air in combination with volumetric flow enables a measurement of true liquid flow
  • Detects changes in process operation due to low pump box levels, air leaks caused by pump, pump/valve packing or other sources of entrained air
  • Accurate and reliable operation over a wide range of process flows, including homogeneous, dispersive and corrosive/abrasive slurries
  • Quick, simple installation with no alignment or coupling gels required
  • Installs while process is running
  • No moving parts, no inherent drift mechanism
  • Requires no recalibration
  • Maintenance free operation
  • Indifferent to pipe material or liners
  • Measurements on Teflon®, Urethane, fiberglass, rubber, HDPE, double-pass chromium, ceramic and concrete-lined pipes


  • Oil sands and minerals processing
  • Chemical processing
  • Pulp and paper industries
  • Consumer products
  • Water and water waste treatment plants
  • Power Generation>
  • Food and beverage industries


Entirely non-contact, “wrap-around” flow sensor design

  • Transmitter with integrated flow processor
  • Programmable by keypad or PC interface
  • Self-diagnostics capability

USB Port and memory stick

  • Remote data logging retrieval
  • Diagnostic reporting to CiDRA technical support

Analog /Digital Outputs

  • Two (2) 4-20 mA current outputs
  • Pulse output
  • Alarm output
  • HART® protocol



SONARtrac® Volumetric Flow and Entrained Air Measurement System Specifications

Parameter Specifications Comments
Flow velocity range Liquid: 3 to 30 ft/s (0.91 to 9.1m/s) Liquid-Only flow conditions may permit flow measurements below 3 ft/sec (a)
Flow rate accuracy ±1% of reading (a)
Repeatability ±0.3% of reading
Entrained air/gas range 0 to 20 % By volume
Entrained air/gas accuracy ±5% of reading, 0.01% to 20% Assumes on-line process pressure available
Entrained air/gas repeatability ±1% of reading, 0.01% to 20%
Pipe diameters 2” to 60” (50.8mm to 1,524.0mm) Metric and custom sizes available(b)
Sensor head Clamp-mounted onto the existing pipe section; designed for single installation Certified to IP55 2”-36” Sensor Length–34.7” (91.4cm)
Over 36” Sensor– 51.2” (130.0cm)
Height within flange diameter of pipe
Lightweight (22 lbs./10 kg for 8” meter)
Stainless Steel designed to IP55
Transmitter with integrated flow processor Programmable by keypad or PC interface Self-diagnostics capability
Operating Temperature Range:
Sensor head process temp.
Sensor head ambient temp.

-4°F to +140°F ( -20°C to +60°C)(c)
-40°F to +212°F ( -40°C to +100°C)
-40°F to +140°F (-40°C to +60°C)
Inquire with CiDRA for temperatures outside these specific ranges
Storage Temperature Range:
Sensor head

-22°F to +176°F ( -30°C to +80°C)
-40°F to +185°F ( -40°C to +85°C)
Cable between transmitter and sensor head PLTC or armored cable with one End connectorized Cable lengths up to 300ft (90m)
Analog input Two (2) 4-20 mA Enables internal logging of optional process parameters
Analog output Two (2) isolated 4-20 mA current outputs One (1) with HART® protocol(d)
Digital outputs> Pulse output
Alarm output
Parameter Specifications Comments
Digital interfaces 10Base-T Ethernet
USB/Memory Stick
RS232 serial
Communication interfaces Standard: RS232/485
Optional: PROFIBUS® PA
Optional: FOUNDATION FieldbusTM
Transmitter local display LCD with backlight(e) Provides flow rate, entrained air/gas, system status, system diagnostics
Data logging capability Yes
Transmitter enclosure NEMA 4X, IP66
Power requirements AC Version: 100 to 240 VAC, 50/60 Hz, 25 Watts
DC Version: 18 to 36 VDC, 25 Watts
Area classification Standard: Ordinary Location
Optional: Class I Division 2,Groups A-D
Optional: Class I Zone 2, Group IIB ATEX
Altitude 5,000 meters Certified for high altitude regions
(a) Inquire with CiDRA for qualifying your application under 3 ft/sec
(b) Inquire with CiDRA for availability and specifications on sizes greater than 36”.
(c) For Zone 2: -4°F to +134°F ( -20°C to +57°C).
(d) Certain restrictions apply for Zone 2 applications.
(e) For Zone 2: No transmitter window for display.

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