Abstract: The inventive device includes a cylindrical housing adapted to receive a filter, the housing having an axis being fixed at a second end to a ventilation circuit flange and having a first end mounted on a mobile companion flange, the companion flange being held in resilient manner under axial tension by holding means under tension, a sheath in alignment with and secured to the housing, about which sheath the companion flange slides axially, a seal disposed between the sheath and the companion flange, three fixed wheels secured to the sheath and projecting outwards therefrom; a cam surrounding the sheath over a certain length and made up of a ring having three ramps each in the form of a helical segment, the ramps receiving respective ones of the wheels, turning of the cam causing the companion flange to move in axial translation; and means for turning the cam. The invention is specially suited to filtering a ventilation circuit in a hostile environment in the nuclear industry.

Abstract: The disclosure describes an apparatus for performing at least two successive chemical reactions in the same container. In order to successively carry out several chemical reactions in the same container (10), e.g. dosing uranium in the presence of plutonium and fission products, the container is placed in a working station above which issue tubes (16, 20) for supplying the products necessary for the reactions. When a product has to be introduced, a computer controls the descent of the corresponding tube. When the product may react inopportunely if it drops into the container (10) outside the time intended for this purpose, the lower end of the product supply tube (16) is automatically laterally displaced with respect to the container, when the tube is in the top position, e.g. by the cooperation of a pawl (102) with a slot (100) forming a cam.