through the production chamber 12 and the housing 11 has one entrance gate 15 and one exit gate 16 the entrance gate 15 and the exit gate 16 each form one gate region 17 18 which have first openings 19 from the outside region 20 of the apparatus 10 into the gate region 17 18 and second openings 21 from the gate region 17 18 into the production region 12 the size of the openings 19 21 is preferably adapted to the size of the bottles 1 or is variable so that the size of the openings 19 21 is as small as possible to avoid an excessive exchange of air among the various regions to make it possible to make manual interventions in the production chamber 12 an access capability is embodied on side of the housing 11 in the form of a double disk door 22 the door 22 has a first disk 24 toward the production chamber 12 and a second disk 23 toward the outside region 20 the spacing of the two disks 23 24 amounts to approximately 40 mm for example in order to indicate that the door 22 does not close the housing 11 in airtight fashion gaps 26 27 are drawn in in the region of the two disks 23 24 toward the housing wall by way of these gaps a purposeful exchange of air takes place between the production chamber 12 and the interstice 25 between the two disks 23 24 and between the outside region.