Method and apparatus for filtering fluid in nuclear power generation

Abstract

A filtering apparatus for a fluid intake of a nuclear power generation facility comprise primary and secondary frames. The primary frame defines an enclosed volume having least one inlet opening, and at least one outlet opening in fluid communication with the fluid intake. A primary filter is supported on the primary frame and covers the inlet opening such that fluid passes into the enclosed volume through the primary filter. The secondary frame is located within the volume enclosed by the primary frame. A secondary filter is supported on the secondary frame and defines an enclosed flow passage in communication with the outlet opening, such that fluid passes into the at least one outlet opening through the secondary filter and the enclosed flow passage.

1 . A filtering apparatus for a fluid intake of a nuclear power generation facility, comprising:
 a primary frame defining a primary enclosed volume, at least one inlet opening in fluid communication with the enclosed volume, and at least one outlet opening in fluid communication with the fluid intake;   a primary filter supported on said frame and covering said at least one inlet opening such that fluid passes into said enclosed volume through said primary filter;   a secondary frame within said primary enclosed volume;   a secondary filter supported on said secondary frame defining an enclosed flow passage in communication with said at least one outlet opening, such that fluid passes into said at least one outlet opening through said secondary filter and said enclosed flow passage.   
     
     
         2 . The filtering apparatus of  claim 1 , wherein said secondary filter is wrapped around said secondary frame to enclose said enclosed flow passage. 
     
     
         3 . The filtering apparatus of  claim 1 , wherein said secondary filter circumscribes said enclosed flow passage. 
     
     
         4 . The filtering apparatus of  claim 1 , wherein said secondary filter defines a cylindrical filtering surface. 
     
     
         5 . The filtering apparatus of  claim 1 , wherein said secondary filter defines a filtering surface having a plurality of polygonal sides. 
     
     
         6 . The filtering apparatus of  claim 5 , wherein the plurality of polygonal sides are supported around the perimeter of each side by the secondary frame. 
     
     
         7 . The filtering apparatus of  claim 1 , wherein said secondary filter is welded to said secondary frame. 
     
     
         8 . The filtering apparatus of  claim 1 , comprising a plurality of said secondary frames forming a corrugation having a plurality of peaks to support the primary filter, the secondary filter supported by each of said secondary frames, each secondary filter defining an enclosed flow passage in communication with a respective outlet opening. 
     
     
         9 . The filtering apparatus of  claim 8 , wherein the secondary frames are angled with respect to fluid flowing through the secondary filter such that the fluid forces secondary frames adjacent each peak toward each other to bias the peaks toward the secondary filter frame. 
     
     
         10 . The filtering apparatus of  claim 1 , wherein said the total surface area of said secondary filters is at least one of 5% of the surface area of said primary filter; at least 10% of the surface area of said primary filter; at least 20% of the surface area of said primary filter; or at least 40% of the surface area of said primary filter. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . The filtering apparatus of  claim 1 , wherein said primary filter has a pore size larger than a pore size of said secondary filter. 
     
     
         15 . A fluid filtering apparatus for a nuclear power generation facility, comprising:
 a fluid conduit;   a plurality of filter modules, each in communication with the fluid conduit for drawing fluid into the fluid conduit through the filter modules, each filter module comprising:
 a primary frame defining a primary enclosed volume, at least one inlet opening in fluid communication with the enclosed volume, and at least one outlet opening in fluid communication with the fluid conduit; 
 a primary filter supported on said frame and covering said at least one inlet opening such that fluid passes into said enclosed volume through said primary filter; 
 a secondary frame within said primary enclosed volume; 
 a secondary filter supported on said secondary frame defining an enclosed flow passage in communication with said at least one outlet opening, such that fluid passes into said at least one outlet opening through said secondary filter and said enclosed flow passage. 
   
     
     
         16 . The filtering apparatus of  claim 15 , wherein said secondary filter is wrapped around said secondary frame to enclose said enclosed flow passage. 
     
     
         17 . The filtering apparatus of  claim 15 , wherein said secondary filter circumscribes said enclosed flow passage. 
     
     
         18 . The filtering apparatus of  claim 15 , wherein said secondary filter defines a cylindrical filtering surface. 
     
     
         19 . The filtering apparatus of  claim 15 , wherein said secondary filter defines a filtering surface having a plurality of polygonal sides. 
     
     
         20 . The filtering apparatus of  claim 19 , wherein the plurality of polygonal sides are supported around the perimeter of each side by the secondary frame. 
     
     
         21 . The filtering apparatus of  claim 15 , wherein said secondary filter is welded to said secondary frame. 
     
     
         22 . The filtering apparatus of  claim 15 , comprising a plurality of said secondary frames forming a corrugation having a plurality of peaks to support the primary filter, the secondary filter supported by each of said secondary frames, each secondary filter defining an enclosed flow passage in communication with a respective outlet opening. 
     
     
         23 . The filtering apparatus of  claim 22 , wherein the secondary frames are angled with respect to fluid flowing through the primary secondary such that the fluid forces secondary frames adjacent each peak toward each other to bias the peaks toward the primary secondary filter. 
     
     
         24 . The filtering apparatus of  claim 15 , wherein said the total surface area of said secondary filters is at least one of 5% of the surface area of said primary filter; at least 10% of the surface area of said primary filter; at least 20% of the surface area of said primary filter; or at least 40% of the surface area of said primary filter. 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . (Canceled) 
     
     
         28 . The filtering apparatus of  claim 15 , wherein said primary filter has a pore size larger than a pore size of said secondary filter. 
     
     
         29 . (canceled) 
     
     
         30 . (canceled) 
     
     
         31 . (canceled)