When you first start working with air-sensitive materials, like titanium or lithium, you will quickly realize that some kind of hermetic enclosure is necessary to protect the application process and potentially the person running the operation as well. That’s why glove boxes and other inert enclosures are standardly used during development of specialty chemical packaging, organic light-emitting diodes (OLED), semiconductors, and lithium batteries, among other products made from air-sensitive materials. Similarly, if the process involves laser welding, 3D printing, or tig welding of any reactive metals, a hermetic enclosure is a must.
Since oxygen and moisture are the enemies in these situations, the goal is to remove these from the enclosure. There are several ways to accomplish this, but here we will focus on constant purging versus a gas management system. Constant purging first requires that an inert gas, such as nitrogen or argon, be pumped into an enclosure to displace oxygen and moisture from the space. The canisters of inert gas are generally labeled for 99.995% purity, but may still have 50 parts per million, or higher, of oxygen or other impurities. So, right from the start it is nearly impossible to reach the desired industry standard of less than one part per million (<1ppm).
In any case, once the oxygen and moisture is reduced enough with the purge, the application can proceed. However, maintaining acceptable values for oxygen and moisture with constant purging requires a continuous flow of large volumes of inert gas. While some inert gases are cheaper than others, with this constant purging you are figuratively blowing money out of the enclosure every minute the system is running.
On the flip side, a gas management system can offer superior benefits - starting with reclaiming roughly 98% of your supplied argon or nitrogen; the other 2 percent is lost during normal operation of the enclosure, its antechambers, etc. After an initial purge of inert gas to remove the majority of oxygen and moisture present in the enclosure, the gas management system then operates in a closed-loop circulation mode, constantly passing the enclosure atmosphere through a purifier column.
Within the column are oxygen – and moisture – absorbing materials. By constantly recirculating the atmosphere through the column, the oxygen and moisture levels can eventually be decreased and maintained at <1ppm.
In addition to a reduction in inert gas consumption, maintaining this repeatable <1ppm, oxygen and moisture-free environment, provides a superior level of process integrity–resulting in improved product quality and higher yield rates. A gas management system will further provide systematic automated control over atmospheric conditions, while refining your house supply of argon or nitrogen. The combination of these safeguards helps eliminate possibility for catastrophic events and provides assurance to end users that they are safer in proximity to these potentially damaging reactive materials. Constant purging does not offer such assurance.
This comparison of constant purging to a nitrogen or argon gas management system is the first in a consecutive three-part blog series to help you better understand the latter process. Next month, we will explain regeneration, a necessary maintenance step when operating any gas management system.
To learn more about the benefits of gas management systems, download Inert's guide. Or, call 978.462.4415. We are happy to explain your options or troubleshoot any problems with existing equipment.