Abstract: The inner compartment of a compressor for noxious fluids is isolated by means of the closure system when the compressor is stationary and disengaged from its driving means. The closure system is controlled by a magnetic attraction system, the external surface of which is uniformly constructed of magnetic material having a small thickness at the level of non-magnetic elements. A particularly noteworthy application of the system is in motor-compressor sets for the transfer of toxic and hazardous fluids employed in the nuclear engineering field.

Abstract: An obturator for the rotor of a machine such as a compressor for special or oxic fluids consists of an annular seal clamped in the active position between stationary knife-edge elements provided on the rotor and movable knife-edge elements carried by an annular supporting member which is capable of moving along the axis of the machine under the action of magnetic means between an inactive position at a distance from the rotor and an active position in which the supporting member is coupled with the rotor as a result of magnetic attraction forces. The movable knife-edge elements are joined to the movable supporting member by resilient means whereby an obturation force of lower value than the magnetic attraction force is exerted in the direction of the stationary knife-edge elements.