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:
Sep. 12, 1989
Filed:
Aug. 23, 1988
Frederick J Geary, Holland, MI (US);
Robertshaw Controls Company, Richmond, VA (US);
Abstract
A control unit for a gas furnace that has an electrically operable pilot gas valve and an electrically operable main gas valve and a method of making the control unit are provided, the control unit comprising an electrical circuit having a gas valve section that comprises a silicon controlled rectifier and a first capacitor and a second capacitor so electrically interconnected together that the capacitors are adapted to be charged on each half wave cycle of a certain polarity of an alternative current source that is imposed on the circuit and that the second capacitor is adapted to discharge through a relay coil that controls the gas valve to energize that relay coil only when the silicon controlled rectifier conducts, the silicon controlled rectifier being adapted to conduct only when the first capacitor is discharged, another section of the electrical circuit being adapted to discharge the first capacitor only on each half wave cycle of the other polarity of the alternative current source.