Tunnels • Brochure

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The Tunnels are comprised of three chambers:
• The Infeed Chamber
• The Sterilizing Chamber
• The Cooling Chamber

Infeed Chamber
The Infeed Chamber creates a thermal barrier between the vial washing room and the Sterilizing Chamber, to protect the vials from contamination and to pre-heat the vials. Vertical unidirectional HEPA-filtered air blows over the vials at 0.5m/s. The Infeed Chamber is pressurized to 28Pa (1Pa=0.1mm), one Pa less than the Sterilizing Chamber. This small pressure drop allows for some hot air to flow from the Sterilizing Chamber to the Infeed Chamber for drying and pre-heating of the vials.

Sterilizing Chamber
The Sterilizing Chamber is fully insulated and can be heated up to temperatures of 350ºC (660ºF). Heat is generated by stainless steel, SCR-controlled heating elements. The sterilization time of the vials is a function of the air temperature and air velocity. The air velocity is adjustable. The thermal cycle is designed to obtain a 3-log pyrogen reduction in 15 minutes (D-value) at a temperature of 250ºC. Every 46.4ºC increase in temperature (referred to E.colli endotoxin), reduces the D-value by 1-log cycle. The Sterilizing Chamber is pressurized to 29Pa, one Pa less than the Cooling Chamber. This small pressure drop causes a counter flow from the Cooling Chamber to the Sterilizing Chamber.

Some options include:
• DOP testing of HEPA filters
• Automatic height setting of infeed and outfeed door

Cooling Chamber
Depending on the tunnel size, one or two cooling coils assist in the cooling of the vials to ambient temperature. Regular tap water or chilled water may be used. Depending on the format, vials stay in the Cooling Chamber for 15-20 minutes. Optionally, the Cooling Chamber can be heat sterilized by HEPA-filtered hot air of 200ºC for a D-value of 7.2 minutes at a temperature of 170ºC. The air pressure in the Cooling Chamber is 30Pa.