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:
Feb. 16, 1988
Filed:
Mar. 17, 1987
Masatoshi Ueoka, Himeji, JP;
Hiroshi Yoshida, Toyonaka, JP;
Atsushi Ohkubo, Himeji, JP;
Shinya Tanaka, Himeji, JP;
Nippon Shokubai Kagaku Kogyo Co., Ltd., Osaka, JP;
Abstract
A method of collecting pyromellitic anhydride, which comprises introducing a high-temperature gas containing pyromellitic anhydride together with an inert cooling gas into an empty column-type collecting device whose wall temperature is maintained at 150.degree. to 200.degree. C., effecting heat exchange between the high-temperature gas and the cooling gas in the collecting device to lower the temperature of the high-temperature gas to 150.degree. to 200.degree. C., thereafter passing the gaseous mixture through the collecting device at an average linear gas velocity of 0.05 to 0.5 m/sec with an average residence time to 5 to 60 seconds, and recovering needle-like crystals of pyromellitic anhydride from the bottom of the collecting device.