The occasional gas purge of a glove box to replace the ambient
air with an inert gas is something that glove box users accept will
take some time, an hour or more for the average glove box. But for
those glove box users that need to access the main glove box chamber
frequently due to the requirements of the process operation, these
time scales can present serious production problems. The alternative
of investing in an evacuable glove box must be the rapid gas purge
The standard practice of glove box gas purge involves releasing
a gas into an enclosed chamber (the glove box) and venting the gas
through a small aperture so as to prevent the backflow of oxygen.
This of necessity increases the pressure within the glove box most
of which are limited to less than 50 mbar (pressure) to avoid permanent
distortion or failure.
Our rapid gas purge system relies upon the accurate measurement
of glove box pressure, the control of gas entering the glove box
under positive pressure and exiting under negative pressure, all
at a high rate of gas flow that substantially reduces the time.
The control is at all times maintained within the glove box design
limitations and a high factor of safety is calculated into the set
up and back-up protection which forms part of the design qualification.
A rapid gas purge system can operate at less than 5% of the normal
gas purge time providing adequate gas supply and feed pipelines
are available. The system is entirely safe in operation, but users
must accept an increased noise level due to the very high discharge
velocity needed to achieve the time reduction.
In practice a balance is struck between available gas supply, feed
pipelines and target gas purge time.
Rapid gas purge systems require accurate pressure measurement and
this makes it unsuitable for flexible enclosures.