Isolation method and apparatus for sterilizing chambers of filling machines

DETAILED DESCRIPTION What is claimed is: 1.
In a sterilizing method which includes the establishment of a toxic sterilizing atmoshpere in a first chamber, the first chamber having entrance and exit apertures, the improvement comprising the step of: creating plural zones of different pressure in series with each of the first chamber entrance and exit apertures, the pressure in said zones being less than either the pressure in the first chamber or the ambient atmospheric pressure, said zones being located exteriorly of the first chamber; and establishing gas flows directed to each of said zones, said directed flows including flows from the first chamber through said apertures to each of said zones and flows directed oppositely with respect to said flows from the first chamber, said oppositely directed flows preventing escape of toxic material from the first chamber to the ambient atmospheres upstream of the chamber entrance aperture and downstream of the chamber exit aperture, said flows from the first chamber preventing ingress of gas comprising said oppositely directed flows to the chamber.
2.
The method of claim 1 wherein the step of creating plural zones of different pressure comprises: partitioning of an air-lock so as to define flow-restricting cross-sections therein; and establishing a connection between one of the flow-restricting cross-sections of the partitioned air-lock and a low pressure source.
3.
The method of claim 2 wherein the first chamber exit aperture is connected by said first chamber exit aperture air-lock to a second chamber via an entrance aperture in the second chamber, the second chamber also having an exit aperture, and wherein said method further comprises the steps of: delivering sterile gas to the second chamber at a pressure above the ambient atmospheric pressure, the sterile gas flowing from the second chamber through the exit aperture thereof to prevent in-flow of air from the ambient atmosphere, the sterile gas from the second chamber also forming a pair of said oppositely directed flows