procedure and device for the sterilization of forpackningsbehallare or parts of them

摘要

Method and device for a two-stage sterilization procedure comprising supply of water vapour to, and microwave treatment of, packaging containers or parts thereof. In a pressurized housing 10 there are two areas, a first one 21 and a second one 22, for applying a microwave field to the containers. The containers 11 are heated to a temperature of about 80 degree as they are conveyed through a feed sluice 12 to the treatment zone, and the saturated steam from the valve 23 is pulsed by means of a valve that can be opened and closed, for example a valve of the magneto-restrictive type. To optimize the delivery of the microwave energy to the condensed, thin layer of water on the surfaces of the packaging containers, a reflector 28 is arranged around the area 22. The amount of steam in the chamber or zone 10 is kept essentially constant by means of a steam trap 32 at the lower end of the zone, by dimensioning the trap with respect to the steam delivered from the steam generator. The outlet from the housing or the zone 10 is provided with a rotating sluice or revolver magazine of the same type as the inlet. A given overpressure is maintained at the outlet from the sluice 35. This prevents re- contamination from the environment before the packaging containers have been filled in a filler 40, which follows directly on a protective casing 39 adjoining the outlet sluice 35. In order, where necessary, to complement the steam with further sterilization medium, there is also a hydrogen peroxide line 42 which supplies hydrogen peroxide in mist form via a valve 43 and at a temperature of about 60 - 80 degree C. The final temperature which is obtained in the microwave area 22 is such that the hydrogen peroxide is heated to a temperature well in excess of 100 degree C, which means that the elimination of microorganisms is extremely good, while at the same time the hydrogen peroxide breaks down and leaves a very small amount of residues. IMAGE