Metrohm 875 KF Gas Analyzer - Manual (Page 9)

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1 Introduction
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1 Introduction
1.1 Instrument description
The 875 KF Gas Analyzer is a robust, modularly designed analysis system
based on tiamo™ for routine analysis at a site.
The system described on the following pages has been devised for the
coulometric water content determination according to Karl Fischer in
gases and allows the analysis of both liquefied gases and permanent
gases. This method is also suitable for very low water contents.
The system comprises an operating unit and an analysis module. The ana-
lysis module is equipped with a base plate to convey the gas and with a
water content determination cell as well as internally with an 851 Titrando
in order to carry out all required analysis steps fully automatically. For this
process, an amount of gas defined by the user is precisely measured with
the flow meter and fed to the connected coulometer cell. Sample residue
and water that might be present in the piping system are rinsed with dry
nitrogen. The water is absorbed by the coulometric reagent and deter-
mined there by way of Karl Fischer titration. In coulometry, the iodine
required for titration is produced by anodic oxidation, and the water con-
tent is subsequently determined. For the determination of liquefied gases,
the samples are first vaporized in a controlled manner and then conveyed
to sample determination.
Please also refer to the manuals and the documentation regarding the
individual components (851 Titrando, mass flow controller, individual
components) in addition to this documentation of the KF Gas Analyzer.
1.2 System description
￭ Robust analysis system with high-quality components for routine analy-
sis tailored to the requirements of users.
￭ Gas-carrying system separate from the electronics and the power sup-
ply.
￭ The base plate with the system components is mounted behind a
hood.
￭ The base plate comprises all components of gas conveyance and prep-
aration as well as the coulometer cell.
￭ The base plate's gas system is pressure-tested.
￭ Nitrogen feed line with drying cartridge for predrying and check valve.
￭ Sample input filter preventing particles from entering the gas system.
￭ Deaeration bypass for pressure release during gas change.