Siemens Aktiengesellschaft

Friedhelm Mueller

Udo Gellert

Arno Steckenborn

Horst Straub

Udo Offermanns

A gas chromatograph for analyzing natural gas, with a first separation column (). A first detector () is provided following the first separation column, the first separation column and the first detector operable to separate or detect propane and higher hydrocarbons. A second separation column () and a second detector () following it are provided to separate or detect carbon dioxide and ethane. A third separation column () and a third detector () following it are provided to separate or detect nitrogen and methane. A controllable changeover device () is provided between the second separation column () and the third separation column () to discharge eluates following methane. The first, second and third separation columns () and the first, second and third detectors () are connected in series. At least the first and the second detectors () are operable to detect a mixture of substances flowing through them in a non-destructive manner.

Gas chromatograph and method for analyzing a mixture of substances by gas chromatography

In order to determine the total sulfur content of a sample (), the sample is uniformly combusted with a flame (). The combustion product sulfur dioxide is fed to a gas chromatograph () in which it is separated from other combustion products () and is then fed to a detector (), which is situated downstream and which is provided for determining sulfur dioxide concentration. The combustion of the sample () is preferably effected in a flame ionization detector (), with whose measurement signal () the detector signal () generated by the detector () is freed from signal contents based on non-uniformities of the combustion process.

System for determining total sulfur content

In a gas chromatograph, an injected sample for analysis () is passed through a separation device () to separate components present in the sample; at the end of the separation device, selected components are detected by a detector () and determined quantitatively on the basis of the detector signal () supplied by the detector. To permit validation and also to increase the accuracy of the analysis, the sample () is determined nondestructively by an additional detector () upstream from the separation device () and is determined quantitatively on the basis of the additional detector signal () supplied by the additional detector (). The result of the quantitative determination of the sample () is used to verify the analysis.

Method for the gas chromatographic analysis of a sample, and analyzer

A gas chromatograph in which the substances of a substance mixture that is to be analyzed are separated in a separation device and are detected in a detector device. An evaluation device () provides a result () in the form of a quantitative determination of given substances depending on the detector signals. To obtain a relatively rapid analysis result, an additional detector device (), which generates additional detector signals () based on the substances that at this stage have not been completely separated, is located in the path of the separation device (). A computational unit () provides a quantitative determination of at least one part of the given substances as a further result (), based on the additional detector signals (). This somewhat imprecise but rapid result can be used for rapid control or regulatory interventions in a process (). The computational precision of the computational unit () can be adaptively improved, based on the result of the evaluation device () which is more precise but takes longer to obtain.

Gas chromatograph

To switch gas flows between gas sources and gas sinks, a gas flow switching device includes gas passages, which communicate with one another and which have connecting points for the gas sources and the gas sinks. Furthermore, the gas flow switching device has a device for setting different pressures. To simplify the construction of the gas flow switching device and to achieve precisely defined pressure and flow conditions without the need for calibration, the gas flow switching device has two plates ( ), which are positioned on top of one another and joined together. The two plates ( ) have congruent channels ( ) on their respective sides that face one another. These channels ( ) have semicircular cross sections and form gas passages ( to ). In addition, at their lateral exit points from the plates ( ), the channels ( ) form connecting points ( to ).

Gas flow switching device

A connecting capillary tube is arranged in a branch coupling and is shorter than the guide bores into which separation columns are introduced. The ends of the separation columns slide automatically over the ends of the connecting tube. The connecting tube is sealed with metal disks instead of graphite ones. The flush gas conduits are so arranged that the dead spaces can be well flooded, reducing adsorption of sample and increasing the performance of the gas chromatograph.

Branch coupling for use between capillary columns of gas chromatographs

A temperature controlled oven chamber for gas chromatography incorporates a first stationary chamber wall, a second stationary chamber wall arranged remote from the first wall, and a displaceable chamber wall which is moveable between a closed position and an open position. In the closed position, the displaceable chamber wall forms the casing of the chamber or housing, and surrounds stationary analytical devices. In the open position, the displaceable wall is moved away from the first stationary wall, thereby opening the chamber or housing and yielding access to the analytical devices. When moving from the closed position to the open position, the displaceable wall will enclose the second wall at least temporarily.

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Linkenheim-Hochstetten, Germany

Friedhelm Mueller