2.3 Glove Boxes
Glove boxes are sealed enclosures that are designed to protect the user, the process or both, by providing total isolation of the contents from the outside environment. They are usually equipped with at least one pair of gloves attached to the enclosure. The user manipulates the materials inside using the gloves. Typically, a glove box has an antechamber that is used to take materials in and out of the box.Types of Glove boxes:
- Controlled Environment (dry box) - These create oxygen and moisture free conditions by replacing the air within the box with an inert gas, such as nitrogen, argon or helium, depending on the type of materials to be worked with. A "rotary vane vacuum pump" is used to remove the atmosphere. Additional accessories may be used, such a gas purifier, to further reduce oxygen and moisture levels for particularly sensitive operations. There are 4 types of this type of glove box based on their leak tightness. Class 1 having the lowest hourly leak rate. This should be inspected by a service company during commissioning, when the gloves are changed, or when there appears to be a problem with the functioning of the glove box.
- Ventilated Glove box (filtered glove box) - These have filters, either HEPA or ultra low particulate, on the inlet and outlet ends of the box and a blower to circulate the air. These provide protection to the user through this filtration and also if the exhaust is connected to building exhaust through a thimble connection. These can have serve in cleanroom applications by reversing the airflow in the chamber to positive pressure.
Regular maintenance and inspection is essential to ensure that a glove box is adequately protecting the user, the environment and/or the product/process. Routine maintenance procedures and the frequency of inspection (or certification) should follow the manufacturers and regulatory recommendations.
There are various tests that can be performed on glove boxes, the suitability of which depends on the glove box and the application. Tests may include pressure decay (for positive pressure), rate of rise (for negative pressure), oxygen analysis, containment integrity, ventilation flow characterization, and cleanliness. The source of a leak can be identified using a Mass Spectrometer Leak Detector, ultrasound, the soap bubble method or use of an oxygen analyzer. For an in-depth discussion of glove boxes and testing, see: AGS (American Glove Box Society) 2007 Guide for gloveboxes – Third Edition. AGS-G001-2007.
Please see other references at the bottom of this page for further details.