Analytical Industries GPR-7500 AIS Trace PPM Hydrogen Sulfide Analyzer - Manual (Page 9)

Advanced Instruments, Inc.
9
5. Operation
Principle of Operation
The GPR-7500AIS H
2
S Transmitter incorporates a variety of advanced electrochemical sensors. These
sensors are very specific to H
2
S and generate an electrical signal proportional to the amount of H
2
S present
in a gas stream. The selection of a particular type of sensor depends on the maximum concentration of H
2
S
contents in the sample stream. Consult the factory for recommendation.
The transmitter is configured in two sections. The signal processing electronics and sensor are housed in a
general purpose NEMA 4X rated enclosure. The terminals of power input, signal output and the intrinsic
safety barriers are mounted on a PCB housed in an explosion proof enclosure.
The two sets of electronics are interconnected using an explosion proof Y-fitting, explosion proof packing
fiber and sealing cement. Once connected, the intrinsic safety barriers limit the amount of power that flows
to and from the signal processing electronics effectively preventing an explosive condition. The analyzer
design conforms to the ATEX directive for equipment as intrinsically safe.
The GPR-7500AIS also meets the intrinsic safety standards required for use in Class 1, Division 1, Group C,
D hazardous areas.