Proximity position switches to replace obsolete legacy mechanical switches
AZZ Nuclear supplies TopWorx non-contact position switches for both linear and quarter-turn valve position indication. The TopWorx GO-Switch uses three internal magnets of varying size and strength plus a large moving “target” magnet that moves with the valve stem. When the target magnet is aligned with the GO-Switch, the two moving internal magnets will move toward the target, closing the contacts and indicating position. When the target is not aligned, the internal moving magnets behave like a spring and move in the opposite direction opening the contacts. The rare earth magnets will only lose 1% of their strength during the100 year qualified life.
The long qualified life, which also includes an additional year post-LOCA, and the fact they are fully submersible, makes them the ideal position switch for both harsh in-containment and balance of plant applications.