Ceramic filter and exhaust gas purification apparatus

Abstract

A ceramic filter including a ceramic block having a honeycomb structure. The ceramic block has filter units which are a porous ceramic sintered body. The filter units are joined to each other by a sealing material layer. The ceramic block has different pressure loss properties or different materials at different portions of the ceramic block.

1 . A ceramic filter comprising: 
 a plurality of filter units each comprising a columnar porous ceramic sintered body having a honeycomb structure; and    a sealing material layer bundling the filter units into an aggregate block,    wherein the plurality of filter units includes ones having a large pressure loss positioned in a portion of the aggregate block having a fast gas flow rate, and ones having a small pressure loss positioned in a portion of the aggregate block having a slow gas flow rate.    
   
   
       2 . A ceramic filter according to  claim 1 , wherein the plurality of filter units comprises the same material.  
   
   
       3 . A ceramic filter according to  claim 2 , wherein each of the filter units comprises a quadratic porous silicon carbide sintered body.  
   
   
       4 . A ceramic filter according to  claim 1 , wherein the ones of the plurality of filter units having the large pressure loss comprise a plurality of filter units having a thick cell wall, and the ones of the plurality of filter units having the small pressure loss comprise a plurality of filter units having a thin cell wall.  
   
   
       5 . A ceramic filter according to  claim 4 , wherein the plurality of filter units comprises the same material.  
   
   
       6 . A ceramic filter according to  claim 5 , wherein each of the filter units comprises a quadratic porous silicon carbide sintered body.  
   
   
       7 . A ceramic filter according to  claim 1 , wherein the ones of the plurality of filter units having the large pressure loss comprise a plurality of filter units having a large cell density, and the ones of the plurality of filter units having the small pressure loss comprise a plurality of filter units having a small cell density.  
   
   
       8 . A ceramic filter according to  claim 7 , wherein the plurality of filter units comprises the same material.  
   
   
       9 . A ceramic filter according to  claim 8 , wherein each of the filter units comprises a quadratic porous silicon carbide sintered body.  
   
   
       10 . A ceramic filter comprising: 
 a plurality of filter units each comprising a columnar porous ceramic sintered body having a honeycomb structure; and    a sealing material layer bundling the filter units into an aggregate block,    wherein the plurality of filter units includes ones comprising cordierite positioned in a peripheral portion of the aggregate block, and ones comprising silicon carbide positioned in a central portion of the aggregate block.    
   
   
       11 . An exhaust gas purifying apparatus comprising: 
 a ceramic filter configured to be installed in an exhaust pipe of a diesel automobile, the ceramic filter comprising a plurality of filter units and a sealing material layer bundling the filter units into an aggregate block, each of the filter units comprising a columnar porous ceramic sintered body having a honeycomb structure,    wherein the plurality of filter units includes ones having a large pressure loss positioned in a portion of the aggregate block having a fast gas flow rate, and ones having a small pressure loss positioned in a portion of the aggregate block having a slow gas flow rate.    
   
   
       12 . An exhaust gas purifying apparatus according to  claim 11 , wherein the plurality of filter units comprises the same material.  
   
   
       13 . An exhaust gas purifying apparatus according to  claim 12 , wherein each of the filter units comprises a quadratic porous silicon carbide sintered body.  
   
   
       14 . An exhaust gas purifying apparatus according to  claim 11 , wherein the ones of the plurality of filter units having the large pressure loss comprise a plurality of filter units having a thick cell wall, and the ones of the plurality of filter units having the small pressure loss comprise a plurality of filter units having a thin cell wall.  
   
   
       15 . An exhaust gas purifying apparatus according to  claim 14 , wherein the plurality of filter units comprises the same material.  
   
   
       16 . An exhaust gas purifying apparatus according to  claim 15 , wherein each of the filter units comprises a quadratic porous silicon carbide sintered body.  
   
   
       17 . An exhaust gas purifying apparatus according to  claim 11 , wherein the ones of the plurality of filter units having the large pressure loss comprise a plurality of filter units having a large cell density, and the ones of the plurality of filter units having the small pressure loss comprise a plurality of filter units having a small cell density.  
   
   
       18 . An exhaust gas purifying apparatus according to  claim 17 , wherein the plurality of filter units comprises the same material.  
   
   
       19 . An exhaust gas purifying apparatus according to  claim 18 , wherein each of the filter units comprises a quadratic porous silicon carbide sintered body.  
   
   
       20 . An exhaust gas purifying apparatus comprising: 
 a ceramic filter configured to be installed in an exhaust pipe of a diesel automobile, the ceramic filter comprising a plurality of filter units and a sealing material layer bundling the filter units into an aggregate block, each of the filter units comprising a columnar porous ceramic sintered body having a honeycomb structure,    wherein the plurality of filter units includes ones comprising cordierite positioned in a peripheral portion of the aggregate block, and ones comprising silicon carbide positioned in a central portion of the aggregate block.    
   
   
       21 . A ceramic filter comprising: 
 a plurality of filter units each comprising a columnar porous ceramic sintered body having a honeycomb structure; and    a sealing material layer bundling the filter units into an aggregate block,    wherein the plurality of filter units includes ones having a large strength positioned in a portion of the aggregate block having a fast gas flow rate and ones having a small strength positioned in a portion of the aggregate block having a slow gas flow rate.    
   
   
       22 . A ceramic filter according to  claim 21 , wherein the plurality of filter units comprises the same material.  
   
   
       23 . A ceramic filter according to  claim 22 , wherein each of the filter units comprises a quadratic porous silicon carbide sintered body.