Thermo Scientific EA IsoLink IRMS System, Руководство по эксплуатации

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2
Analytical Principles
Pneumatic Circuit
Thermo Scientific EA IsoLink IRMS System for CNSOH Operating Manual 39
Helium Management (He
M
) Module
This module allows the reduction of helium consumption for each sample. The module is shown in
Figure 36 , and consists of the following components. See Table 16 .
Figure 36. Helium Management Valve Block (Left) and Needle Valve Holder for Split Adjustment (Right)
Helium Management (He
M
) Valve Block Description
The Flash IRMS Elemental Analyzer is equipped as standard with the Helium Management (He
M
)
module. The He
M
module reduces the He consumption in an EA significantly, e.g. up to >60% for a
CNS triple analysis from a single sample. Large volumes like the reactors require high flows of
>80mL/min. Since peak broadening starts in the reactors higher flows are favorable to enhance peak
shape. He
M
module allows high reactor flows of 180 mL/min. This increase in carrier flow is
compensated by recirculating up to 2/3 of the He flow back into the system for purging
.
He
M
module
works through a valve block which is installed underneath the isothermal GC oven of the EA). See
Figure 37 .
Figure 37. HeM Valve Block Installed
Table 16. Parts of the He
M
Module
Component Description and Function
EV1 - NV1 Pyrolysis — opens and closes the split and controls the split flow
EV2 - NV2 Combustion — opens and closes the split and controls the split flow
EV3 - NV3 Vent — opens and closes the split and controls the split flow for large sample analysis
He
M
Valve Block
Needle Valves