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:
Apr. 15, 1986
Filed:
Jun. 20, 1985
Richard T Cuscino, No. Andover, MA (US);
Russell L Shade, Jr, Boxford, MA (US);
General Electric Company, Lynn, MA (US);
Abstract
A recirculation apparatus is employed to recirculate a portion of the feedwater in a vertical-tube economizer to reduce the likelihood of reverse flow and steaming at startup and/or low load. A recirculation valve, opened at low load, directs part of the water from the economizer outlet back to the inlet of the boiler feed pump via a deaerator. The recirculated water not only increases the pumping head across the economizer tube planes, but also reduces the temperature rise of the increased water flow rate passing through the economizer tubes which now enters the economizer tube bank at an elevated temperature. The reduced temperature rise in a given single pass through a tube plane consequently reduces the buoyant force which opposes the pumping head in downflowing tube planes. Additionally, the amount of water being recirculated at these light load conditions results in a total boiler feed pump flow which is well within the capacity of a given pump size without consideration of the present invention. Furthermore, a simple control system could be employed whereby the recirculation valve is opened or closed dependent upon the level of gas turbine loading compared to a predetermined stability threshold load level.