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What's the difference between positive and negative pressure glove boxes?

April 28, 2016 at 11:00 AM


Today's glove box applications are as varied as the world's many industries. From additive manufacturing and atomic layer deposition, to semiconductor research and tungsten inert gas welding, glove boxes must be tailored for their precise purpose. When considering whether you need a positive pressure glove box, or one equipped for negative pressure, you must first ask yourself what you wish to protect: the process, or the person.

In other words, could the experiment or function that you intend to complete be adversely affected by outside elements, such as those found in the air we breathe? Or, could the operator be in harm's way if otherwise completing the task without sufficient safeguards?

Protecting the Process

As technology has evolved, so has use of new manufacturing materials, like reactive metals. The aerospace and medical device industries, for example, wouldn’t be what they are today without titanium. However, those who work with titanium know it easily reacts with oxygen, thereby requiring a glove box to protect the process via an inert atmosphere created with positive pressure. Development of lithium-ion batteries is another example of when a positive pressure glove box is called for, because a moisture-free and N2-free environment is necessary to protect the process involved in lithium-ion battery testing and development.

To achieve the desired atmosphere, glove boxes are equipped with gas management systems that remove oxygen (O2) and moisture (H2O) from helium, argon, nitrogen, or whatever combination is called for to create ideal working conditions (i.e. an inert atmosphere). A properly maintained, positive pressure glove box can create a continuous >1 ppm O2 & H2O environment. In fact, no matter what kind of inert atmosphere you need to protect your process, it can be engineered with a positive pressure glove box and related gas management system.

What's more, the hermetically sealed positive pressure enclosure can be outfitted with most any tool the operator needs for the job, such as 3D printers, hydraulic presses, ovens, hot plates, spin coaters, solar simulators, and more - all enclosed within the glove box.

Protecting the Person

Glove boxes have been used to protect operators far longer than their process-related cousins, much in part due to the defense industry's extensive history of working with hazardous radioactive agents. Nowadays, though, far more users - in a wide variety of industries - are working with unsafe materials, including specialty chemicals and volatile drugs.

To protect the person in these scenarios, negative pressure is used to contain contamination and/or explosive reactions. The negative pressure effectively pulls the hazard away from the person. Just as with other glove boxes, these negative pressure glove boxes can also be integrated with equipment and tools of most any kind.

In cases when both the person and process need protection, a tailor-made glove box system can be engineered to offset application-specific concerns. For example, if fire protection is a priority, an inert gas management system could eliminate risk of fire, while also providing the desired inert atmosphere to protect the process.

When you're ready, Inert's team of engineers will design the ideal controlled environment for performance, safety, ergonomics, serviceability and manufacturability so you are best equipped to maximize market opportunity.