Granted Patent
Utility
US 4,999,089 · App. 07/413,734
Cracking furnace
Inventors:
Noriaki Nakase, Mamoru Hokkedo, Etsuji Yamamoto, Masahiko Yoshida, Yutaka Kitayama
Patented Case
View Patent ↗
Granted: Mar 12, 1991
Filed: Sep 28, 1989
Inventors
Noriaki Nakase
Mamoru Hokkedo
Etsuji Yamamoto
Masahiko Yoshida
Yutaka Kitayama
Assignees (at issue)
Mitsui Engineering & Shipbuilding Co., Ltd.
Mitsui Petrochemical Industries, Ltd.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.