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SELECT DISTINCT patent.*, YEAR(date) as year FROM patent LEFT JOIN category ON category.patent = patent.patent AND category.type = patent.type WHERE (category.class = '324') AND (category.subclass = '553') ORDER BY date ASC, patent, type

Total of 1 patents found where: Class is '324'; Subclass is '553';

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T / S Patent Date Description Patentee Category Assigned To
 1924
U 1,515,864 November 18, 1924 Method of Testing Insulators
Testing method by extending the flashover distance
LAPP, Grover W.
Testing  

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