The vacuum glove box is the original airtight enclosure and is still widely used today. The standard design of a vacuum glove box has a heavy steel outer frame that provides stability, insulation and physical strength. On one side of the frame are two doors, each with a gasket seal to provide an airtight sealing in conjunction with an o-ring at the base.
Inside the enclosure is a workbench or table with a rubber or silicone coated work surface. This coating helps to create an airtight seal against leakages from materials spilt in the glove box while being worked on.
Basic Structure of a Vacuum Glove Box
The gloves of the Vacuum Glove Box are made of stainless steel to support the frame and withstand exposure to harsh chemicals. Common seal materials include silicone rubber, silicone elastomer, EPDM rubber and natural rubber. In addition, many vacuum glove boxes have a safety interlock that ensures that both doors are closed before the vacuum pump can be started.
Both doors must be sealed and screwed shut with a pneumatic tool to ensure a strong airtight seal and enclosure is airtight. In addition, a pressure gauge is installed on the manifold where it can be easily monitored during use.
Working Process
When the vacuum pump starts, it removes air pressure from the interior of the glove box, and a small leak in the glove box will cause air to seep into it. This is known as saturation, and if this happens, an o-ring or gasket can be damaged due to a tightening of its size.
Therefore, when working inside a vacuum glove box, an inert atmosphere must be maintained by pumping inert gas. Any materials in the glove box should be assessed before being brought inside for any possible microbial contamination. The material is then placed into the glove box for a designated time before being checked for contamination.
The glove box is maintained by cleaning out any solvents that have been used in the material being worked on and replacing seals if necessary. A vacuum glove box has become a prominent part of every laboratory.
