Dual Purge System; High-Flow, for Glovebox, 120 V

• Ensures a constant positive pressure inside glove boxes and other enclosures to block contamination and moisture inflow
• Automatically activates high-flow purge in response to pressure drop to ensure fast, effective purge of particles and moisture when an air lock is opened
• Operates in tandem with humidity controllers to maintain any desired sub-ambient moisture level (down to 0% RH with the NitroWatch®, or down to 1.0 ppm of water with the DewWatch™)
• Guards against pressure damage to chamber doors and seals

In most applications, glove boxes must be continuously purged with nitrogen or another process gas in order to ensure a controlled environment free of contaminants and moisture.

Unfortunately, however, a steady gas inflow can't guarantee the clean, dry conditions you require. A flow adequate to maintain a safe internal positive pressure when doors are closed is insufficient to overcome the backflow of outside air that occurs when a door or air lock is opened. A higher-level purge that might guard against this backflow wastes nitrogen and leads to overpressures that warp doors and damage seals.

Variable-Purge Security

The Glove Box Dual Purge™ System solves these problems. It employs an air pressure sensor to activate high- and low-flow gas purges, and is especially designed for use with Terra's plastic and 304 stainless steel glove boxes.

The pressure sensor in these units indicates pressure drops below a programmable low-pressure threshold. When gas pressure falls below this point, as it does when an access door or air lock is opened, the high-flow purge is activated to quickly and effectively purge any moisture and contaminants that might enter the chamber—before they can affect sensitive materials inside.

When pressure returns above the set point, the high-flow purge continues to purge the chamber for 60 seconds (programmable), and then the low-flow purge is automatically reestablished. The Automatic RB® (Relief/Bleed) Valve, which is required for use with the Dual Purge™ System, safely relieves excess pressure before it can cause any damage.

The dual-purge capabilities of these units ensure that contaminants and moisture stay outside the processing chamber and at the same time guard against dangerous overpressures that can lead to warped doors, failed seals—even explosions! And because the Dual Purge System delivers only as much gas as is necessary, it economizes on nitrogen consumption; tests show that in many applications, these units can pay for themselves in a matter of months.

The Dual Purge™ System incorporates a flowmeter, a line pressure gauge and glove box pressure gauge for easy monitoring of nitrogen flow and pressure. A "Low-Pressure" alarm is activated if the incoming line pressure is ever interrupted. This dual audible/visible alarm alerts you to a disconnected supply line, an empty gas storage pod, or other problem that could spell disaster for contents of a glove box!

The Dual Purge System operates in tandem with Terra humidity controllers to provide the most effective moisture control available.

The NitroWatch® includes a humidity sensor that continuously monitors the internal RH level and activates the Dual Purge™ to automatically maintain any sub-ambient humidity threshold you require (down to 0% RH). For more critical requirements, select the DewWatch™, which works with the Dual Purge™ System to maintain ultra-low dew points (with moisture levels as low as 1.0 PPM by volume). In all of these applications, the Automatic RB® Valve is required to ensure safe relief of overpressures that can build inside a chamber.

Specifications

• Dimensions: 12"W x 11.25"D x 7"H 305 mm x 286 mm x 178 mm
• Weight: 16 lbs. 7257 g
• Flowmeter: 0-20 SCFH
• Line Pressure Gauge: 0-60 psi
• Chamber Sensor: 0 - .4" WG (factory set at 0.02" WG)
• Inlet/Outlet: .25" (6 mm), accepts .25" (6 mm) OD polyethylene tubing
• Case Material: 304 Stainless steel; brass or stainless steel internal fittings
• Power Requirement: 110/220VAC, 50/60Hz (requires no manual power setting
• Timer Adjustment: 0-8 minutes (factory set at 1 minute)