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:
Nov. 10, 1981
Filed:
Aug. 29, 1979
Hitachi, Ltd., Tokyo, JP;
Abstract
A timer circuit arrangement for use with a digital combustion control system functions to check failure of a safety timer which stops the combustion operation in the event that ignition is not completed within a predetermined time. The arrangement has a simple circuit which checks the safety timer in advance of initiation thereof. A pre-purge timer, which determines a predetermined time for feeding only combustion air into the combustion chamber for purge thereof in advance of the combustion, and the safety timer are built with a unitary construction. A series connection of flip-flop circuits is provided for carrying out frequency division of clock pulses to obtain predetermined times, and the flip-flop circuits for the safety timer are constituted by at least a part of the flip-flop circuits for the pre-purge timer so that the pre-purge may continue infinitely when the safety timer become out of order, thereby preventing the operation for combustion and ensuring safety of operation.