Enhanced flue gas damper mixing device

摘要

A gas mixing device has a plurality of interleaved rows of adjustable louvers. When at least two flowing gas streams are received that are desired to be mixed, the louvers of each row directs the gas streams in a direction different from that of the adjacent rows, mixing the gas streams. When effectively only a single flowing gas stream is received, the louvers are positioned vertically thereby reducing the pressure drop across the gas mixing device.

主权项

1. A flue gas duct system having a backpass for receiving flue gases from a furnace that operates under various loads, comprising:
at least one heat exchanger disposed within the backpass adapted to extract heat from the flue gases; a lower flue section being a flue gas conduit coupled to the outlet of the backpass adapted to receive the flue gases; an upper flue section being a flue gas conduit coupled to downstream flue gas processing devices; a middle flue section being a flue gas conduit adapted to convey the flue gases from the lower flue section to the upper flue section; a bypass coupled to the backpass at the middle flue section upstream of an economizer, where the bypass is a flue gas conduit; an inlet control damper disposed within the lower duct, adapted to adjust the amount of flue gases that flow from the lower flue section to the middle flue section; a bypass control damper disposed within the bypass duct, adapted to control the amount of flue gases passing from the backpass to the middle duct, thereby bypassing the economizer; and a damper mixing device for mixing two gas streams in an elongate flue as duct comprising: a plurality of first rows of louvers, each first row of louvers having a plurality of louvers having adjustable louver vanes pivotable on a pivot about a respective axis, the adjustable louver vanes being positioned in a first direction when at least two gas streams are being received, causing the flue gases passing through the adjustable louver vanes of the plurality of first rows of louvers to be mixed, and positioned in a second direction aligned with the direction of the flue gas when effectively only one gas stream is being received; wherein each respective row of the plurality of first rows of louvers is spaced from the remaining rows of the plurality of first rows in the longitudinal direction of the flue gas duct; a plurality of second rows of louvers interleaved, with the plurality of first rows of louvers, each second row of louvers having a plurality of louvers with adjustable louver vanes pivotable on a pivot about a respective axis, the adjustable louver vanes may be positioned in a direction different from the first direction when at least two gas streams are being received causing the flue gases passing through the adjustable louver vanes of the plurality of second rows of louvers to be mixed, and positioned in the second direction aligned with the direction of the flue gas when effectively only one gas stream is being received; wherein each respective row of the plurality of second row of louvers is spaced from the remaining rows of the plurality of second rows of louvers in the longitudinal direction of the flue gas duct; and a control unit connected to the louvers, adapted to position the louver vanes of the first rows of louvers in the first direction, and the louver vanes of the second rows of louvers in the direction different from the first direction when at least two gas streams are being received, and for positioning the louver vanes of the plurality of first and second rows of louvers in the second direction aligned with the direction of the flue gas when effectively only a single gas stream is being received.