Teledyne 326, 327 and 328 - Oxygen analyzers - Manual (Page 26)

Teledyne Analytical Instruments 3-6
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to the exact configuration of the analyzer covered by the manual, and details
concerning the sample handling system should be taken from that drawing.
The outline drawing provides installation details concerning sample or
calibration gas conduit sizes and connecting points.
In systems with a separate sample probe, you must mount the probe,
provide the sample and calibration system for the analyzer, and make sure
that the probe is protected from the elements and RFI.
3.3.2 Recommended Span Gas 3.3.2 Recommended Span Gas 3.3.2 Recommended Span Gas 3.3.2 Recommended Span Gas 3.3.2 Recommended Span Gas
The 326R series has been designed to employ air as the calibration gas.
TAI feels that the known oxygen concentration of air (20.9%) is the most
reliable standard available. The volume represented by the cell manifold and
sample passages has been reduced to a minimum so that the instrument will
recover rapidly to the 0-10% range analysis when you follow the proper
calibration procedure. (Calibration gas may be specified.)
If the ranges of the analyzer do not encompass the oxygen content of
air, span gas will be required to calibrate the instrument. The cylinder span
gas will have to be manifolded with the sample gas externally. TAI can
furnish gas selector panels, in a variety of configurations, to suit the
customer’s needs.
Only a span gas with a certified composition should be used, and the
cylinder must be equipped with a metallic diaphragm regulator. If the span
gas is compressed air (cylinder supplied), a metallic diaphragm-type regula-
tor is not required, since diffusion will not alter its oxygen concentration.
When compressed air is supplied by a compressor, a throttle valve should be
adequate.
3.3.3 Vent Connection 3.3.3 Vent Connection 3.3.3 Vent Connection 3.3.3 Vent Connection 3.3.3 Vent Connection
Wherever possible, vent the analyzer directly to the atmosphere. If
venting directly is not possible, the following conditions must be met in vent
line installation:
1. The vent line must be constructed so that no appreciable
backpressure (from vent line restriction) is experienced by the
analyzer. ¼-inch tubing is recommended.
2. The vent line must terminate in an area that experiences no more
than normal barometric pressure changes.
3. The vent line must be installed so that water and/or dirt cannot
accumulate in it.