Teledyne 2020 - Explosion proof thermal conductivity analyzer - Manual (Page 33)

Teledyne Analytical Instruments
Thermal Conductivity Analyzer Installation 3
3-15
ambient pressures, and pressures must vary no more than the normal
barometric changes.
Install VENT lines such that water and dirt cannot accumulate in
them.
Note: If your 2020 has the –V option, see Note at end of Pressure
and Flow Rate Regulation, above, for gas vacuum/flow
considerations.
3.4.4 SAMPLE Gas
In the standard model, sample and calibration gases are introduced
through the SAMPLE fitting. The gases must be Tee'd into the Sample inlet
with appropriate valves.
The gas pressure in should be well regulated. (See section 3.4.1.) The
sample line pressure regulator should be installed as close to the sample
line as possible to minimize sample line lag time.
If greater flow is required for improved response time, install a bypass
in the sampling system upstream of the analyzer input.
3.4.5 REFERENCE Gas
A gas of fixed composition is needed as a reference to which the
sample gas will be compared. The reference gas is normally selected to
represent the main background gas of the analysis.
For most applications, a constant supply of reference gas flowing at
the same rate as the sample is required for best results. However, in many
cases the flow of reference gas can be slowed to about 0.08 scfh
(40 cc/min) with good results.
For some applications, an optional sealed air reference is installed. In
sealed-reference sensors the reference side of the detector cell is filled with
air and sealed. This eliminates the need to have reference gas constantly
passing through the cell.
NOTE: For instruments equipped with the optional sealed air refer-
ence, there is no REFERENCE inlet or reference VENT port.
It is highly recommended that the same cylinder of gas be used for
both the REFERENCE gas and the ZERO gas.
Pressure, flow, and safety considerations are the same as prescribed
for the SAMPLE gas, above.