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:
Oct. 28, 1986
Filed:
Aug. 14, 1985
Hitachi, Ltd., Tokyo, JP;
Abstract
An apparatus for controlling the drum water level of a drum boiler prevents the boiler system from being tripped off which would otherwise be caused by an excessive fall in the drum water level immediately after the start of load runback, by increasing the real feed water flow rate in such a manner that a feed water flow rate demand signal obtained from the drum water level deviation is corrected by a feed water flow rate increment signal obtained from the amount of load reduction (load demand--load reference after load runback) at the time of load runback. In addition, the fact that the drum water level stops falling and starts to rise is detected, and the feed water flow rate demand signal is adjusted so as to take a medium value between the real feed water flow rate and the real main steam flow rate, thereby preventing the boiler system from being tripped off which would otherwise be caused by an excessive rise in the drum water level.