Pass through box is inserted from the non-sterile, contaminated side and is cleaned by a jet of filtered air. The doors are controlled by a system that avoids both doors from opening simultaneously, thus preventing the cleaner environment from being contaminated.
The principle behind this operation is based on the vertical laminar flow which passes through the pass box from top to bottom. It maintains a cleaning level of ISO 5 inside the Box, which is, therefore, higher than the entry environment of the product. The filter unit consists of an electric blower and a HEPA filter which guarantee constant clean conditions. This is done by constantly recirculating the internal air and part of the intake air is filtered through a special opening at the top of the cabinet.