Patent ID: 8215379
Filing Date: 2012-07-10
Classification: B01D,F22B,F22D,Y02E

Abstract:
1. An improved vapor generator having a pressure vessel, a plurality of heat exchanger tubes extending within the pressure vessel, the heat exchanger tubes adapted to accommodate a flow therethrough of a hot primary fluid, the heat exchanger tubes having heat exchanger surfaces, an economizer disposed within the pressure vessel, the economizer being spaced-apart from the pressure vessel to provide an annular downcomer passage, the economizer enclosing a portion of the heat exchanger surfaces of the tubes to preheat feedwater flow introduced into the economizer, the improvement comprising: an annular support ring disposed within the annular downcomer passage, the annular support ring having a plurality of openings circumferentially spaced about the annular ring for conveying feedwater therethrough, and a plurality of elongated cylindrical tube filters each having a closed top end, an open bottom end covering and corresponding to each of the plurality of openings, and a plurality of filter holes perforating the cylindrical portion of each of the cylindrical tube filters for capturing and retaining debris carried by the feedwater fluid before it passes into the economizer to prevent entry of the debris into the economizer.