Supplemental Manual
High-
IsoDry™ RH Control System
©
Copyright 2017 Terra Universal Inc. All rights reserved • Revised November 2020 • Document No. 1788-26
Terra Universal, Inc. • TerraUniversal.com • 800 S. Raymond Ave. • Fullerton, CA 92831 • TEL: (714) 578-6000 • FAX: (714) 578-6020
3
All of Terra’s IsoDry™ Desiccator Cabinets employ a similar nitrogen-flow design:
1.
High-purity nitrogen gas is fed into a plenum at the rear of the desiccator (single-column design) or directly into
one of the chambers (double-column design) where it mixes with the air inside the cabinet. When the Relative
Humidity (RH) climbs above set-point level, a high-flow purge is activated.
2.
The IsoDry™ Gas Dilution Module continuously circulates this nitrogen-rich air mixture throughout the
desiccator, further blending the nitrogen gas with the air and diluting any moisture present inside the cabinet.
3.
The influx of nitrogen gas pressurizes the desiccator, and air is released through the automatic relief/bleed (RB)
valves, allowing the concentration of nitrogen gas in the desiccator to rise until the desired RH level is reached.
At this time, the nitrogen purge reverts to a low flow.
The IsoDry™ System is made up of four main components:
1.
The IsoDry™ Desiccator Cabinet
2.
The IsoDry™ Dual Purge
3.
The IsoDry™ NitroWatch
4.
The IsoDry™ Gas Dilution Module
IsoDry™ Dual Purge System
The Dual Purge System controls the nitrogen gas input. The system provides two levels of nitrogen purging to protect
your stored materials: Low-level purge and high-level purge.
•
Low-level purge maintains the minimum pressurization necessary to block out moisture and contaminants while
the desiccator doors are closed.
•
The high-level purge activates when the RH level rises above the set-point and is designed to minimize the
impact of introducing outside air to the stored materials. An adjustable time delay maintains the high-level purge
for a set time after the set-point is reached, followed by a return to low-level purging.
The IsoDry™ Dual Purge System is designed for enclosures that feature several access doors. It relies on the
IsoDry™ NitroWatch to activate the high- and low-level purges.
Each unit features a system line pressure gauge and regulator, internal positive pressure gauge, a 2-amp fuse
(located inside the housing), a flowmeter, and all necessary gas line connections.
In addition, each unit features an alarm that flashes if the inlet line pressure falls below 30 psi. This alarm alerts the
user of a problem with the supply line.
Automatic RB Valves are required in nitrogen-purged desiccators to prevent dangerous pressure buildup.
WARNING
