Inline Aeration Meter CGS

The Concentration Gas System CGS to measure fluid aeration

Aeration measurement has never been so easy.

The core element of our CGS (Concentration Gas System) is a measuring tube without any mechanically moving parts. The determination of the gas concentration (CG) in two-phase flows is based on an innovative procedure which, in contrast to the radionuclide method, is hazard-free.

Measuring the change of the complex fluid impedance in comparison to the unaerated medium, CGS offers decisive advantages in all fields of application concerning the gas concentration. Whether it's oil aeration in engines or gear boxes, foamed adhesives or aerated food products: Our CGS is the perfect tool for almost every gas-in-fluid problem.

Another advantage is its high resolution. No matter if you have microbubbles of minimum diameters or larger air pockets entrained in your oil: our system allows you to get precise measurements independently of both the physical form and the flow conditions of the two-phase mixture. Thanks to its integrated pressure sensor you can always compare your results by means of the additional standardized value CG0, which gives you the gas concentration at atmospheric pressure.

Key features

  • Compact and accurate inline fluid aeration meter
  • Continuous displaying of the aeration / concentration of undissolved gas in fluids
  • Constant accuracy from 0.1 to 100.0 vol% of gas
  • Inline-measurement without any mechanically moving parts
  • Suitable for all electrically non-conductive types of liquids
  • Fully upscalable system: different sensor sizes available for different flow rates
  • Non-destructive measurement, independent of the direction of flow
  • Integrated temperature and pressure measurement
  • 4 Output values: Temperature; Pressure; CGp (actual gas concentration at measured pressure); CG0 (standardized value of gas concentration at atmospheric pressure)
  • Retroactive accounting of the equivalent gas content at atmospheric pressure
  • High degree of accuracy
  • Short measuring time & simple handling
  • Compact, portable measuring instrument
  • Standard digital interface (RS-232, adaptable to USB) for an optional connection to your WINDOWS PC (intuitive software included)
  • Analog output for all measured values

Fields of application

The standard measuring tube of the CGS is equipped with two UNF 9/16" connectors* and can easily be integrated into your fluid circuit. Due to its continuous inline measurement of the volumetric gas concentration in fluids, the system offers new possibilities, e.g. for the continuous inline monitoring of oil aeration in hydraulic pipes, combustion engines or gear boxes, or for the optimized application of aerated adhesives.

The CGS can furthermore be applied as a regulation and control unit in many areas of technical production in which the concentration of gas represents an important quality feature, or in areas in which the systematic addition of gas can reduce production costs.

The following fields of application summarize the features of the CGS:

  • Inline live data
    Survey and control the important criterion of oil aeration for the design of motors, gear boxes, oil pumps or turbochargers
  • Optimization of machines and machine parts
    Design new machine elements with reduced oil aeration
  • Optimization of fluid development
    Develop fluids with optimized aeration and degassing behavior
  • Process survey and control
    Optimize processes in the application of aerated fluids and adhesives

(* 3/8" male and other screw-on adapters available)


In general the CGS consists of only two components: the measuring tube with three integrated sensors (CG sensor, PT100 temperature sensor and pressure sensor) on the one hand, and the corresponding control and evaluating system in an electronic unit on the other hand.


Both ends of the standard sensor (left picture) are equipped with UNF 9/16" (dash 6) connectors which can also be adapted to e.g. 3/8" or 1/2" fittings and which simplify the mounting of the measuring instrument into the fluid circut. The standard sensor is suitable for main stream installation with 0.5 - 5 l/min (< 1.3 gpm). If your application has higher flow rates we recommend bypass installation with the optional bypass installation kit. However, if main stream measurement is preferred, there are larger sensors available as well.


There are different types of electronic units / housings available: as alternatives to the aluminum desktop housing (bottom left) with separable LEMO connectors we offer a small compact housing for mobile use (bottom center), as well as a large plastic housing with terminals (bottom right) which is designed for control cabinet installation. All CGS units are available either with 110-240 V AC or with 9-36 V DC supply.

CGS Standard, Mobile & Large Box


Fast or superfast measurement?

Once you have decided which sensor and electronics may be ideal for your application, there is one more thing to figure out: Would you like to measure at standard speed - once per second - or at high-speed - ten times as fast?

With a measuring time of only 100 ms, the CGS in high-speed version might come in handy if you have a dynamic application with unsteady or inhomogenuous aeration.

Operating your CGS

No matter the type of sensor or electronics, or if it's a standard or a high-speed version. Every CGS system for the determination of gas concentration in fluids can be used in stand-alone mode or can be operated with your WINDOWS computer via standard interface RS-232. In addition, each system comes with the powerful CGS software that enables you to trace and interpret your measurements.

If you prefer controlling your data with your master computer, you can simply use the analog output of the CGS (0-10 V or 4-20 mA) to transfer the measured live data of all relevant parameters.


Julabo Thermostat used for calibration of flucon CGS

Getting started with your aeration measurement is quite easy: Before first usage the CGS only needs to be calibrated once on your specific unaerated oil over the full temperature range of your process, with +/- 10°C of extra range recommended. For measuring with various fluids the CGS comes with a fluid list that allows you to save up to 20 different oils (sets of parameters). This enables you to quickly switch the presaved parameters by use of the menu, e.g. to use the sensor on another testbed running a different type of oil.

To make the calibration easier we offer optional fluid thermostats that can be controlled by the CGS system.



Technical data of the CGS

Measuring range 0 to 100 vol% Gas
Accuracy approx. +/- o.1 vol% Gas
Measuring media & Flow rates electrically non-conductive fluids

for flow rates < 5 l/min (1.3 gpm): use standard sensor

for higher rates: use bypass installation or large sensor

customized sensor tubes for main stream installation also available upon request

Measuring time Standard: approx. 1 s,

high-speed version (measuring time approx. 100 ms) available upon request

Temperature measurement PT 100, +/- 0.1 °C
Temperature range -30°C to 150°C
Pressure range max. 10 bar
Dimensions measuring tube (WxHxL) Standard sensor: 40 x 110 x 165 mm;

Large sensor: 60 x 127 x 218 mm

custom-made sizes available upon request

Material measuring tube special steel (1.4571)
Connection Standard sensor: 2x UNF 9/16″-18Gg (dash-6) male

screw-on adapters (G 3/8" or others) available upon request;

Large sensor: 2x G1" female;

Dimension electronic unit (WxHxD) Standard (Aluminum): 235 x 150 x 370 mm

Large (with connecting terminal): 330 x 150 x 300 mm

Compact (for mobile applications): 240 x 95 x 115 mm

Data communication (computer) RS-232 interface (CGS software for WINDOWS included)
Analog output temperature 4-20 mA / 0-10 V
Analog output CGp-signal 4-20 mA / 0-10 V
Analog output CG0-signal 4-20 mA / 0-10 V
Analog output pressure 4-20 mA / 0-10 V
Power supply 110-240 VAC or 9-36 VDC

Contact us

You are interested in our aeration sensor CGS or have any questions?
Please contact us today and we´ll be happy to help.


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Fluid aeration measurement with flucon