Abstract: The cabin is integral with a shield which separates it from the working environment and which can replace a perimetral part of the wall or the like which separates said environment from the outside. In correspondence with said shield the cabin comprises a sealed (by suitable seal gaskets), flameproof and explosion-proof door providing access from said environment and comprising an armoured viewing window. On the side opposite that comprising the door the cabin has a movable wall which is hinged and ejectable. In the walls perpendicular to the preceding there are apertures or passageways for the entry and exit of the can conveyor. Analogous apertures or passageways are provided in the shield, these being at least partly closable by guillotine plates when required. In the region in which the conveyor extends in the open between the shield and cabin, means are provided to direct air streams onto the cans.