Teledyne 4020 – Hydrocarbon analyzer (special version for automatic background gas switching) - Manual (Page 20)

Introduction Model 4020
Teledyne Analytical Instruments 2
 Extensive self-diagnostic testing at startup and on demand
with continuous power supply monitoring.
 RS-232 serial digital port for use with a computer or other
digital communication device.
 Analog outputs for concentration and range identification (0-
1 VDC standard and isolated 4-20 mA dc).
 Superior Accuracy
1.2 Principle of Operation
The sample gas is mixed with a fuel (normally a composition of
hydrogen and nitrogen) and burned in an atmosphere of “blanket air”.
The ions formed in the burning process cause an electrical conduction
between two electrodes in the combustion chamber (or detector cell) that
is amplified by a highly sensitive electrometer-amplifier circuit. The
electrical output of the electrometer-amplifier is directly proportional to
the quantity of flame ionizable hydrocarbons present, and is linear over
the range of 0-60,000 PPM methane.
1.3 Analyzer Description
The information contained in this manual describes individual analyzers
of the Model 4020 standard series that includes automatic background gas
switching. The versatility of this analyzer is inherited through the long
heritage of the earlier analog unit. Very often, special customer driven design
features are incorporated and will require additional or supplementary
information in addition to the information described in this manual. These
special considerations, if applicable, will be described in detail on specific
application pages as Addenda to this manual. When the Model 4020 is a part
of a larger system, it is subordinate to that system, and specific installation
and operation conditions of that system will apply. Consult system sections
of the manuals for those applications, where conditions specific to those
systems will be detailed.
To best suit the needs of the purchaser, specialized designs may have
been adopted. Details of the design differences may be found in the
various drawings (outline, assembly, schematic, wiring, and piping
diagrams) in the drawings section at the rear of the manual.
The standard analyzer is housed in a sheet steel equipment case
flush-mounted in a 19" rack. The front interface panel is mounted on a