The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 13, 1996
Filed:
Dec. 12, 1994
NGK Insulators, Ltd., , JP;
Abstract
A porous ceramic filter has properties such that a porosity of the filter is more than 45% and less than 60%, a volume of pores having a pore size of less than 40 .mu.m is more than 60% of total volume of pores of the ceramic filter and an inequality of 1000M+85N.gtoreq.530 is satisfied, wherein M (m.sup.2 /g) is a specific surface of total pores continued from a surface to an inner portion of the filter and N (.mu.m) is a surface roughness of a surface of the filter. Preferably, the porous ceramic filter has a thermal expansion coefficient of less than 0.5.times.10.sup.-6 /.degree.C. within a temperature range of 40.degree..about.800.degree. C. in a direction parallel to a flow passage of the filter. The porous ceramic filter according to the invention is preferably used for eliminating soots in an exhaust gas from a diesel engine, and has a long operating time and requires less frequent filter regenerations.