Corrosion-resistant jacketed active magnetic bearing

A jacketed active magnetic bearing for a rotary machine having a rotor in contact with a process gas, the magnetic bearing comprising a bearing armature of completely or almost completely uninterrupted magnetic material secured to said rotor, a bearing stator made up of electromagnet windings associated with a yoke of completely or almost completely uninterrupted magnetic material that presents end pole pieces disposed at a short distance from said bearing armature but without making contact therewith, at least one position detector comprising a detector armature of completely or almost completely uninterrupted magnetic material mounted on the rotor and a detector stator comprising electromagnet windings associated with a yoke of completely or almost completely uninterrupted magnetic material, and electronic control circuits connected to said bearing electromagnet windings and to said detector electromagnet windings;

• said bearing stator being protected by a first jacket of magnetic anti-corrosion material that co-operates with first housing portions to form a first leaktight housing enclosing said bearing stator, and said detector stator being protected by a second jacket of non-magnetic anti-corrosion material that co-operates with second housing portions to form a second leaktight housing enclosing said detector stator;
• wherein said first jacket is made of a ferritic stainless steel, wherein said first housing portions have insert parts that are also made of ferritic stainless steel, and that are connected by first welds to said first jacket, said insert parts also being connected by second welds, before said electromagnet windings and said bearing stator yoke are put into place, to a housing end-wall portion made of a magnetic anti-corrosion material, and wherein said completely or almost completely uninterrupted magnetic material forming said bearing armature and said detector armature is a ferritic stainless steel.