Advertisement
Chapter 9
Optional Equipment
Internal
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 port.
Zero/Span and
Zero and span gas should be supplied at atmospheric pressure. It may be
Sample Valves
necessary to use an atmospheric dump bypass plumbing arrangement to
accomplish this.
See the "Installation" and "Operation" chapters for more information.
The Internal Permeation Span Source option is designed to provide a
Internal
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
malfunction or drift. Because this option does not precisely control dilution
Source
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 multipoint 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 9–1 shows how this option is integrated with the Model 43i Trace
Level-Enhanced components. Energizing the sample valve V1 shuts off the
sample flow and permits the flow of zero air for analysis. When valves V1
and V2 are energized, the flow of zero air mixes with air containing SO
2
from the permeation oven. This mode of operation provides a single point
span check.
Thermo Fisher Scientific
Model 43i Trace Level-Enhanced Instruction Manual
9-1
Advertisement
Troubleshooting
