Mechanical strainer unit

In a nuclear reactor suppression chamber having at least one conduit exiting therefrom and a strainer secured to said conduit within the chamber, said improvement comprising said strainer having:

• A. a plurality of centrally apertured plates positioned along a common axis and in parallel and spaced relationship, each of said plates including a plurality of perforations of a given diameter so that liquid can pass through the plates and said central apertures being in communication with the conduit;
• B. spacers positioned between adjacent plates to maintain the plates in spaced relationship and form communicating passages of a predetermined size with the central apertures;
• C. inner and outer rings alternately positioned in the spaces between plates, the inner rings having a diameter smaller than the outer rings and positioned adjacent the central apertures preventing entrance from the communicating passages to the central apertures and forming a first straining area limited by adjacent plates and the inner rings, the outer rings positioned adjacent the periphery of the plates preventing entrance to the communicating passages and forming a second straining area limited by adjacent plates and the outer rings;
• and
• D. connecting means joining the strainer unit to the conduit and maintaining the strainer in assembled relationship.
• whereby the flow of liquid from the suppression chamber is initially into the first straining area, through the perforations of the plates into the second straining area and into the central apertures and the conduit.