Perma Pure GASS-2040 - Manual (Page 9)

9 GASS-2040 User Manual | Original Instructions
It is important that the dryer removes water in vapor state only. If liquid water is introduced
into the dryer, efficiency will decline and the dryer could fail to perform altogether. Tubing
elongates approximately 10% over its dry length when saturated with liquid water causing
tubing to kink inside housing. Nafion dryers will operate most efficiently when a portion
of the dryer is heated to prevent sample from condensing.
2.6 Ammonia Scrubber (optional):
The optional ammonia scrubbing canister must be used when ammonia or urea is used for the
purpose of lowering NO
x
levels or any time ammonia is present in sample stream.
Ammonia salts can deposit in dryer tubes and cause permanent loss of drying efficiency if not
removed from the sample stream. An ammonia scrubber consists of a polysulfone and 316 SS
housing filled with a phosphoric acid based media and inert ceramic saddles. This media will
require periodic replacement. See section 6.3 for replacement instructions.
2.7 Purge Heatless Air Dryer (optional):
If -40 °C dewpoint purge air is not available, a heatless air dryer can be installed
in the GASS-2040 to dry the compressed air supply. Outlet of heatless dryer will be connected
to standard purge gas flow controls. Operation of heatless dryer is fully automatic and
continuous, and should not require any maintenance as long as oil free compressed air is used.
2.8 Purge Air Eductor (optional):
When the sample is under more than five inches of water vacuum, a purge air eductor is required.
Eductor generates a vacuum to drop pressure of purge gas to prevent collapsing of Nafion tubing.
2.9 Z-Purge (optional):
For hazardous environments to meet Class I, Division II specifications (Refer to Appendix E).