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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 = '252') ORDER BY date ASC, patent, type

Total of 2 patents found where: Class is '252';

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T / S Patent Date Description Patentee Category Assigned To
 1889
U 411,384 September 17, 1889 Packing for Steam Pipes
Composition material used to coat the outside of pipes to act as an insulator against heat		 LEE, Charles Tennant
 Composition 1/2 to The Gould & Watson Co.
 1934
U 1,973,076 September 11, 1934 Insulator
RFI: coat crown with gold, platinum, bismuth & semi-conductive area		 HUNT, Marsden H.
 RFI Westinghouse Electric & Mfg. Co.

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