Sample Lines And Connections; Sample Conditioning - Ametek 5000 Instrument Manual

Sample Lines & Connections
Cleaned and passivated 316L stainless steel* with 0.125 to 0.25 in. OD sample line tubing is
recommended for use throughout the sample system. Note that ordinary stainless steel tubing
can have an internal finish that may cause moisture holdup and slow analyzer response. Exhaust
vent tubing should have an OD of 0.25 inch or greater to prevent back pressure from affecting
the flow rate to the measuring cell.
To avoid sample contamination, the sample stream should not come in contact with plastic, rub-
ber, oil, grease, or dirt. Use Teflon
compression) connections. Check all sample line connections with a bubble-type leak detector.
Low temperature and/or high pressure can cause moisture to condense on the sample line walls.
Water (or other liquids) in the sample line can migrate to the analyzer cell causing the crystal to
stop oscillating. This will result in erratic moisture concentration data until the liquid evaporates
and crystal returns to normal operation state. If this happens, the calibration of the instrument
will no longer be valid. Full calibration and span adjustment will be necessary.
!
Water migration to the analyzer cell will destroy the hygroscopic crystal coating. If analyzer
function does not return to normal, the cell must be replaced.
CAUTION

Sample Conditioning

Conditioned sample gas is normally used as the reference gas for moisture analysis. Instrument
air or nitrogen may be used if the sample has a high level of particulate or if sample flow rate is
too low. Whether from the sample or a separate source, the reference gas passes through a stan-
dard dryer containing 3A molecular sieve and an in-line filter (both included) before entering the
field unit. Note that use of a reference gas different from the sample gas can cause background
interference; refer to Appendix B for data correction procedure.
For some special applications, it is recommended that the sample should also be run through a
contaminant trap and a super-activated dryer. Refer to the supplemental information supplied
with the system to determine if these optional components are to be used.
!
Moisture contamination of the dryer(s) can cause incorrect sample moisture data. To prevent
this contamination, never leave either end of a dryer open and exposed to atmospheric moisture.
CAUTION
* PN 571061017; SST tubing, 0.125 in. OD
2-14 5000 Multi Point Moisture Analyzer
fluorocarbon resin tape or Loctite
®
545 on all threaded (not
®