- Multi-chamber desiccator cabinets isolate different types of stored materials
- Built-in rear plenum distributes dry gas evenly to each chamber of the desiccator cabinet
• Multi-chamber desiccator cabinets isolate different types of stored materials
• Built-in rear plenum distributes dry gas evenly to each chamber of the desiccator cabinet
• Choose material types to support your application:
• Amber acrylic desiccator cabinets absorb most ambient light
• ESD-safe static dissipative PVC is ideal for sensitive electronics
• Clear acrylic desiccator cabinets offer a low cost alternative for dry storage without strict cleaning protocol
• Factory-installed flowmeter allows nitrogen gas purging of the entire cabinet
• Reduced impact on other chambers when one door opens
• Order with Dual Purge and NitroWatch systems for enhanced humidity control
• Stainless steel racks installed in each chamber; shelves adjust in 1" increments
• Chrome-plated, ergonomic LiftLatches™ do not scrape the chamber like ordinary rotary latches
• Stainless steel-framed doors extend service life and provide a better door seal
• Mechanically attached, one-piece gasket does not creep or crack
• Automatic RB® Valves release moisture-laden air from the cabinet and prevent over-pressurization
• Electrical grounding available; specify when ordering (included standard on Static-Dissipative PVC models)
• Includes one flowmeter, one automatic relief/bleed valve per chamber, and one perforated stainless steel shelf (order additional shelves separately)
Not Shown: Flowmeter - Flowmeter included for manual regulation of flow rate (choose Dual Purge/NitroWatch systems for automated control)
Because the likelihood of ESD (electrostatic discharge) increases in a low humidity environment, Terra strongly urges that you consider these measures as part of your static control program.
Acrylic, commonly used in storage enclosures, is a prolific static generator. Wiping an acrylic desiccator generates surface charges that can discharge onto ESD-sensitive components. Static-dissipative PVC prevents this danger.
This material not only dissipates static charges safely but also eliminates the particle attraction that static charges create. Surfaces stay clean, inside and out, making this material perfect for use in cleanrooms.
Because static-dissipative PVC is transparent and highly durable, it can be used in place of acrylic in nearly any application, desiccators included. It features a surface resistivity of approximately 10^7 ohms per square and is completely noncontaminating—with no measurable outgassing—and it resists a wide range of chemicals.
Note: To protect Static-Dissipative PVC surfaces, desiccators made of this material must include stainless steel shields installed at the bottom of each chamber.
By ionizing nitrogen molecules as they pass through the desiccator plenum wall, ionizing nozzles neutralize electrostatic charges on all interior surfaces. They provide practical ESD control for charged nonconductive materials, which cannot dissipate charges to ground. And because they eliminate static attractive forces, they help control contamination: in a statically neutral environment, any airborne particles that enter a desiccator are more likely to remain airborne and to be purged out of the cabinet.
All Terra desiccators made of static-dissipative PVC feature grounding terminals on a standard basis. The surface resistivity of this material (around 10^7 ohms/square) allows controlled dissipation of static charges from any surface in the cabinet, including shelves. Conductive grounding connections safely direct charges to a grounding terminal (standard on SDPVC cabinets; order separately for acrylic cabinets below).
For smaller components that can be stored on shelves, Terra's grounded stainless steel shelving provide a 100% ESD-safe enclosure.
Grounded conductive plates (such as shelves) create a Faraday cage that prevents penetration of static charges. Because these conductive units are removable, they also protect your sensitive components from ESD as you transport them from one location to another.
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.
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.
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!
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.