Internal Zero/Span And Sample Valves - Thermo Scientific 43iQ Instruction Manual

Optional Equipment

Internal Zero/Span and Sample Valves

Internal Zero/Span
With the zero/span assembly option, a source of span gas is connected to
the SPAN port and a source of zero air is connected to the ZERO IN port.
and Sample Valves
It may be necessary to use an atmospheric dump bypass plumbing
arrangement to accomplish this.
For more information, refer to the "Installation and Setup" chapter and the
"Operation" chapter.
Internal
The Internal Permeation Span Source option is designed to provide a
simple span check. This option is intended as a quick, convenient check to
Permeation Span
be used between zero and span calibrations for determining instrument
Source
malfunction or drift. Because this option does not precisely control dilution
gas flow, it should not be used as a basis for instrument zero and span
adjustments, calibration updates or adjustment of ambient data.
Whenever there is an indication of possible instrument drift or
malfunction, a full zero and calibration (Level 1) should be performed prior
to corrective action. For further information on zero, span and calibration
of air pollution monitors, refer to Section 2.0.9 of the US EPA's Quality
Assurance Handbook for Air Pollution Measurement Systems (Volume II).
Figure 9–9 shows how this option is integrated with the 43iQ components.
During normal operation, the pump draws zero air through the permeation
oven and out the instrument exhaust. When performing a single point span
check, the sample valve is energized, closing the sample valve, and the Perm
valve is energized, opening the perm valve. This directs the zero air/SO gas
2
mixture from the permeation oven gas through the heated hydrocarbon
kicker and into the optical bench.
9-17
Thermo Scientific 43iQ Instruction Manual