available for uses involving thermal stress. Polypropylene offers greater chemical resistance.
This glove box features two 1/8" pipe-tapped ports on the rear of the top surface, one for feeding in the purge gas and one for
monitoring the internal cabinet pressure. These ports allow you to control the gas flow into the glove box.
Dual Purge System
Effective nitrogen control is provided by either the Glove Box Dual Purge System alone (for variable purge control), or the Glove Box
Dual Purge System and NitroWatch (for automatic humidity control). These control systems greatly enhance the efficiency of the
glove box by automatically regulating the nitrogen fed into the system.
The Dual Purge System provides a continuous low-level purge to maintain a constant internal positive pressure that helps to block
out contaminants and economize on nitrogen. The minute it senses a drop in this positive pressure (such as when an air lock is
opened) it automatically initiates a temporary high-level flow that quickly flushes out any moisture or contaminants that might enter
the chamber. When the selectable threshold pressure is reestablished, the system then reactivates the economical low-level purge.
The Dual Purge System incorporates a flowmeter and pressure regulator (to control the incoming flow of nitrogen) and an internal
positive pressure gauge (to monitor the pressure inside the glove box), and a 1/2 Amp fuse (inside the housing). It also includes
a built-in pressure alarm and an open chamber alarm, which provide audible and visible alarms when line pressure falls below a
preset point or the chamber is open at some point, such as an air lock left open. An alarm silencer is included to mute the audible
alarm if desired.
NitroWatch™
Add the NitroWatch™ to the system for completely
automated humidity control. It provides a continuous
readout of the internal humidity level and operates
together with the Dual Purge System to automatically
maintain any sub-ambient internal humidity level (down
to 0%RH) you may require.
The Humidity Sensor, which senses the humidity level, is
mounted inside the controlled environment. It employs a
fast-response capacitive probe whose capacitance is
proportional to the humidity level. The sensor is capable
of measuring humidity over the entire humidity range,
from 0 to 100% RH, with an accuracy of ± 3% RH at a
temperature of 68 degrees F. The voltage output of the
sensor is directly proportional to the humidity.
A 3-prong connector allows easy connection of the sensor to the Control Unit.
The Control Unit provides the indicators and controls necessary to set the desired humidity level and to measure the actual humidity
level inside the chamber.
The rear panel of the NitroWatch features a 3-prong outlet for connection to the R/H sensor, and a telephone-jack outlet for
connection to the Dual Purge System (the desiccator sensor switch port is not used in glove box applications). It draws power from
the Dual Purge System and requires no separate power connection.
The Humidity Sensor senses the relative humidity level inside the chamber; the output signal is then compared to the set point level.
Whenever the internal humidity exceeds the value of this set point by more than 0.5% RH, the controller signals the Dual Purge
System to initiate a high-flow nitrogen purge, which forces moisture-laden air out of the Automatic RB (Relief/Bleed) Valve. When
the relative humidity falls to the proper level (within 0.5% of the set point), the high-flow purge is automatically shut down.
The NitroWatch thus ensures the optimal environment for stored materials and at the same time eliminates nitrogen waste. Keep in
mind, however, that the lower your humidity level set point, the more nitrogen the system will consume (and the greater the internal
positive pressure will be).
Refer to Terra Universal Catalog No. 105 for further information on nitrogen consumption.
Quick-Start Operating Guide
Series 100 Polymer Glove Box
© Copyright 2004 Terra Universal Inc. All rights reserved.
• Revised December 2004 • Document No. 1800-42
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Terra Universal, Inc. • TerraUniversal.com • 700 N. Harbor Blvd. • Anaheim, CA 92805-2553 • TEL: (714) 526-0100 • FAX: (714) 992-2179
NitroWatch™
Glove Box
Dual Purge™
System
Glove Box
Automatic
RB Valves™
NitroWatch™
Sensor
GAS OUT
HUMIDITY SENSOR SIGNAL
GAS IN
POSITIVE PRESSURE
POWER 120 VAC
NitroWatch/Dual Purge/Glove Box System
Functional Diagram
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