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Terra Part #PriceShips in
Dual Purge 9500-05 63974 $2,1801-3 Days2
NitroWatch 9500-06 63975 $9971-3 Days3
NitroWatch Humidity Sensor 9500-02A 28937 $6981-3 Days4
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Product Details

• 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)

• 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

Features & Benefits

Features and Benefits

Desiccator Dual Purge System

Dual Purge™ System

  • 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)
The variable Purge Advantage:
Low Flow Conserves N2
when Doors Closed
High Flow Efficiently Purges
Moisture when a Door Opens
Automated Humidity control
Low Flow Conserves N2
when Doors Closed and %RH Under Set Point
High Flow Efficiently Purges
Moisture when Door Opened or %RH Under Set Point

Dual Purge and NitroWatch

Terra’s Dual Purge and NitroWatch relative humidity controllers maintain a low-RH set-point inside a desiccator or glove box; they provide variable purge control that ensures continuous positive pressure and eliminates nitrogen waste.

IsoDry Dual Purge

Terra’s Dual Purge and NitroWatch relative humidity controllers maintain a low-RH set-point inside a desiccator or glove box; they provide variable purge control that ensures continuous positive pressure and eliminates nitrogen waste.

IsoDry NitroWatch Controller

Dual Purge and NitroWatch RH Controllers work in tandem to maintain your low-humidity set-point and protect sensitive parts, without wasting N2 gas

Static-Dissipative PVC Plating

Terra's SDPVC features bonded dissipative layers that resist abrasion. SDPVC desiccators retain their surface resistivity of 106 - 108 ohms/square indefinitely (unlike spray-on coatings that can wear off after a few years), protecting your materials against ESD damage. Further, the control of static charges eliminates particle attractions, helping maintain clean surfaces.

Desiccator Dual Purge System

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.

Doors - The First Failure Point of a Desiccator Cabinet

Terra’s stainless steel door frames eliminate the need for internal reinforcements, which create particle surfaces and compromise cleaning. Unlike other doors with glue-on anti-bow pieces, Terra’s doors use no adhesives. This eliminates particle traps, sources of outgassing—and extends the strength and service life of the desiccator.

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Manuals & Resources

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  • FasTrak 24/7 provides a 24/7 commitment to meet the shipping date YOU specify, regardless of quoted lead times.
  • FasTrak 24/7 assigns a dedicated production team plus a dedicated senior expeditor working three shifts to meet your delivery specification.
  • FasTrak 24/7 guarantees* to meet the agreed-to specified ship date.

Call for pricing. FasTrak service fees cover costs of additional services only, without additional profit.

 * Terra's FasTrak services limited guarantee: to ship on the ESD or date specified OR to refund up to 100% of FasTrak charges. This guarantee covers no direct, special, consequential or other damages and is strictly limited to up to 100% of the amount paid for FasTrak service. When a specified ship date is missed due to factors outside Terra's control (vendor performance, deliveries by shipping companies, etc.) and random factors such as accidents, the credit of up to 100% of the FasTrak 24/7 may not apply. FasTrak service requested after order placement will be quoted and accepted based on available time remaining before required ship date.

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