Trace Gas Inlet (TGI) for HALO

Currently the standard inlet for gas phase measurements is under development. This intake will be part of the basic equiment provided by the DLR-FB for scientific users working with in-situ equipment aboard the HALO aircraft.

The design of the intake allows different tubing configurations to be integrated into the inlet structure, thus providing a high flexibility to the scientific user community. To achieve this, the tubing and ducting system is built in a modular way enabling an individual sampling equipment - according to the respective demands - to be integrated by simply exchanging the complete tubing assembly. So it is possible for the scientific users to prepare and to bring their own tubing assembly and mount it to the inlet during the preparation phase of an experiment.

General mounting options:

1. The Inlet can be mounted on each of the prepared aperture plates
2. Two different heights are available: The smaller one is intended to be operated in the forward positions, the longer version for rearward mounting positions of the aircraft
3. The inlet can be mounted with one forward directed sampling tube and 3 backward directed tubes or vice versa
4. Each of the tubes can have a diameter up to 1/2 inch, e.g. 1/2" or 3/8" or 1/4". Any combination of those diameters is possible
5. The material of the tubes can be chosen according to the requirements, e.g. stainless steel, PTFE or PFA
6. Different feed-throughs are possible. The pressure flange can be exchanged with the assembly
7. Special configurations are possible as long as the assembly fits to the body

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The prototype shown below is actually being prepared for mechanical testing.

At present, two basic configurations for the tubing assemblies are suggested: One with a flat plate and an alternative layout with a chamfered surface which leaves more room for larger fittings. The electrical feed-throughs are meant to connect the anti-ice provisions and an optional heating of the sample tubes.

To allow these tubing assemblies to be built by the scientific users, an "interface control document" will be prepared to provide all information necessary to meet the requirements of compatibility to the TGI structure.