AVL Gas Divider GDU/GNU SL™

The AVL Gas Divider (AVL GDU) is a precision tool to perform accurate calibrations (linearizations) for gas analyzers.
It is available with a certified ISO 17025 calibration.


The AVL Gas Divider (AVL GDU) can be used for all kind of AVL gas analyzer equipment. The device is available with 15 cut points, 63 cut points, 255 cut points and 1023 cut points.

The device is available in each case with or without integrated CLD converter testers.

The device is available in each case as an integrated device for installation in an 19″ cabinet or as an external device.



Technical Data


1. XD01 voltage supply 24 V DC

2. XG01 Ethernet interface

3. XG06 RS 232 interface

4. XM02 inlet for synthetic air (SA) carrier gas

5. XM03 inlet for oxygen O2 (converter tester only)

6. XM04 gas mixture outlet to exhaust gas measuring system

7. XM05 dilution gas inlet

8. XM06 exhaust air outlet

9. XM01 inlet for nitrogen (N2) carrier gas


The iCAL GDU/GNU SL can be operated in the following ways:

– iGEM Device Control Software

– Web-based User Interface



Up to 1023 cut points

By using the combinations of up to 10 sonic nozzles, 1023 cut points (division steps) can be realized. This allows to dilute a gas of e.g. 10,000 ppm down to 9.77 ppm. Highest number of cut points (up to 1023) reduces the number of gas bottles needed.

Best accuracy, stability and reproducibility

By using sonic nozzles in stainless steel and high precision pressure sensors with automatic drift compensation, a dilution accuracy of better than 0.5 % of the cut point can be reached. With unprecedented long-term stability and reproducibility. This guarantees the most accurate analyzer calibrations possible.

Fast purge / stabilization times

Optimized flow design, realized by using virtual flow simulation and 3D printing of complex stainless steel structures, provides much faster purge and stabilization times compared to conventional mixing devices. This also saves calibration gases and reduces operational cost.

Best results also with problematic gases

The GNU SL was optimized especially for low concentrations of gases that tend to stick to surfaces, like e.g. NH₃. The GNU SL provides faster signal stabilization and higher accuracy also with such gases, thanks to the new flow design combined with use of best suited materials and surfaces.

Certified accuracy – Robust operation

The GNU SL comes with NIST traceable and ISO 17025 certified calibrations, each nozzle calibrated with a flow accuracy of better than 0.2 %. Since sonic flow nozzles as secondary flow standards, they remain their accuracy during their life time i.e. as long as they are not getting dirty.

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