Elster GmbH
___________________________________________________________________________________________________________
EnCal 3000 Quad– Hardware Manual
22/06/2017
10/52
1.1.3
Sample Injector
The sample injection must assure a precise injection of sample into the flow of the carrier gas.
In principle the amount injected must be very precisely controlled, both in volume, pressure, temperature and
flow (to avoid viscosity effects) to guarantee a high level of repeatability of the analytical results, but in
practice the normalisation of the measured concentrations will compensate for a large part of the fluctuations
of these parameters.
However, to reach a repeatability for the heating value below 0.02 %, these parameters do have effect and
need to be controlled to a high degree.
The used MEMS technology allows a fundamental improvement of the sample injection quality compared to
the traditional fine-
mechanical technologies used for most of the current process GC’s on the market. The
picture below shows a typical MEMS sample injector, etched in silicon channel, with membrane valves to
control flow directions.
This injector allows for a very precise control of the injection volume and temperature, on a remote base.
fig. 1-4 MEMS Sample Injecto
