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Dual Purge™ System

Dual Purge™ System

Dual Purge™ System

CE Mark All desiccator cabinets and Dual Purge/
NitroWatch control systems.
CE Declaration
  • Cuts nitrogen waste, guards against oxidation
  • Ensures a constant positive pressure inside desiccators and other enclosures to block contamination and moisture inflow
  • Automatically activates high-flow purge when doors are opened to ensure fast, effective purge of particles and moisture
  • Operates in tandem with NitroWatch® to maintain any desired sub-ambient moisture level (down to 0% RH)
  • Guards against pressure damage to desiccator doors and seals
  • Door switches are highly reliable—rated for over 10 million operations

Desiccators 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 is opened. A higher-level purge that might guard against this backflow wastes nitrogen and leads to over-pressurization that warp doors and damage seals.

Dual Purge System Offers Variable-Purge Security

The Desiccator Dual Purge System solves these problems by providing a higher flow level only when it's needed, and only for as long as it's needed.

It relies on a sensor switch installed on each door. During normal operation, with all doors closed, the system maintains an economical low flow of nitrogen into the desiccator to ensure a constant positive pressure of about 0.05" WG (Water Gauge)—just enough to block out moisture and contaminants.

When a door is opened, the sensor switch immediately activates a high-flow purge of nitrogen into the desiccator's plenum chamber that minimizes the influx of moisture and contaminants.

When the door is closed, the high-level gas flow continues to purge the desiccator for a selectable period of time, ensuring that any moisture that does enter the chamber is quickly forced out of the Automatic RB® (Relief/Bleed) Valve, before it can degrade sensitive materials. This time delay is adjustable, so you can retain the high-flow for a longer time when you suspect moisture contamination may have occurred. Note: The Automatic RB® Valve must be ordered separately.

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 over-pressurization 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.

Safety Alarms Ensure Worry-Free Operation
The Dual Purge System incorporates a flowmeter, a line pressure gauge and a variable purge mechanism. 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 desiccator or glove box!

NitroWatch™ Controller Expands Capabilities

The Dual Purge System operates in tandem with Terra's NitroWatch System to fully automate moisture control.

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 NitroPlex™, which combines this automatic humidity control with multiplexed purge capability. In all of these applications, the Automatic RB Valve is required to ensure safe relief of over-pressurization that can build inside a chamber.

Dimensions: 12"W x 11.25"D x 7"H (305 mm x 286 mm x 178 mm)
Weight: 16 lbs. (7258 g.)
Flowmeter: 0-20 SCFH
Line Pressure Gauge: 0-60 psi
Chamber Sensor: 0 - 0.4" WG (factory set at 0.02" WG)
Inlet/Outlet: 0.25" (6 mm) (accepts 0.25" (6 mm) OD polyethylene tubing)
Case Material: 304 stainless steel; Chrome plated 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)

Dual Purge System

Variable purge system boosts desiccator efficiency and cuts nitrogen costs.
  Cat.# Price
Control Unit 9500-05 $ 2,137
Sensor Switch (installed)
One per door required
1600-49 $ 82
0.2 Micron filter
Removes contaminants from gas line.
1314-00 $ 1,237
Click any price to add to cart.
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File Type File Name Publication Date
White Paper (PDF) On-Site Nitrogen Generation: Cheaper, Easier, More Reliable
Learn how on-site nitrogen generation saves money by not having to order canisters of inert gas for desiccators, glove boxes and analytical instruments. You can make your own purified nitrogen from compressed air using a sophisticated membrane module (find out how it works!).
Tech Resource (PDF) Which Nitrogen Control System?
A comparative guide to Terra’s control system features and benefits.
Manual (PDF) Desiccator Cabinets and RH Controllers: Doc. # 1800-40
This manual provides installation and operating instructions for the following Terra desiccator lines: Adjust-A-Shelf, Pass-through, Wafer Box, Kitticator, Tape and Reel, Farracator and Series 100 through 400. The manual also covers the following RH Controllers: Flowmeter, Dual Purge System and NitroWatch.
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