Teledyne 4020 - Hydrocarbon analyzer - Manual (Page 23)

Total Hydrocarbon Analyzer Operational Theory
Teledyne Analytical Instruments 7
Operational Theory
2.1 Introduction
The Model 4020 Total Hydrocarbon Analyzer is composed of three
subsystems:
1. Sample System
2. Detector Cell
3. Electronic Signal Processing, Display and Control
2.2 Sample System
Note: The measured component for the Model 4020 is
hydrocarbon content. Hydrocarbon lubricants and
conditioners, as well as synthetic plastics are common to
instrumentation supply processes. Utmost precaution must
be taken at all times to specify hydrocarbon-free gases,
regulator diaphragms, and supplies.
All components used to control the sample and supporting gases, as
well as the combustion portion of the detector cell, are located inside the
enclosure, behind the electronics control panel and are accessible by
sliding the front of the unit out from the rack enclosure. Adjustments are
made using the appropriate control on the front panel.
The software in the Model 4020 allows the system to be used for
analyzing a sample gas in two different backgrounds, O
2
and N
2
. A
separate calibration must be performed on each sample/background
combination. The calibration parameters are stored internally and are
appropriately applied when the user selects the specific background gas
in use. See Section 4.7.2 Background Gas Selection.
Note: The user must supply the necessary valves and any
associated switching equipment for delivering the correct
sample/background gas combination to the analyzer.