Economizer with soot blower

An economizer construction for use in recovering heat from flue gases passing upwardly through a vertical stack via a heat transfer fluid and adapted to be cleaned with a pressurized fluid comprising:

• a housing defining a generally vertically extending flue gas passage therethrough about a generally vertical central axis;
• a helically wound heat transfer coil positioned in said flue gas passage for placing the heat transfer fluid in a heat exchange relation with the flue gases passing through said flue gas passage, said heat transfer coil defining a generally vertically extending opening centrally therethrough concentrically of said central axis and having a first prescribed diameter;
• and
• a soot blower assembly including an elongate soot blower lance having an outside diameter smaller than said first prescribed diameter of said central opening through said heat transfer coil, mounting means for rotatably positioning said soot blower lance within said central opening through said coil so that the longitudinal axis of said lance is generally coaxially oriented along said central axis;
• drive means for selectively rotating said lance about said central axis, and fluid supply means for supplying the pressurized cleaning fluid to said lance, said lance defining a fluid passage therein in communication with said fluid supply means and defining a plurality of orifices therein for directing streams of the pressurized cleaning fluid from within said fluid passage across said central opening and onto said heat transfer coil to clean same and said mounting means including gas bearing means attached to said lance and control means for supplying pressurized fluid to said gas bearing means to operate said gas bearing means so that said gas bearing means rotatably supports said lance while pressurized cleaning fluid is supplied to said lance;
• wherein said lance includes a mounting shaft on the upper end thereof and wherein said gas bearing means includes a gas housing defining a fluid chamber therein into which said mounting shaft rotatably extends;
• a lower bearing plate mounted in said fluid chamber and dividing said fluid chamber into a lower subchamber below said lower bearing plate and upper subchamber above said lower bearing plate, said lower bearing plate defining a central opening therethrough through which said mounting shaft rotatably extends into said upper subchamber;
• an upper bearing plate attached to said mounting shaft in said upper subchamber so that said lance is supported thereby with said upper bearing plate overlying said lower bearing plate, said lower bearing plate defining fluid passages therethrough and said control means constructed and arranged to supply the pressurized cleaning fluid into said lower subchamber whereby the pressurized cleaning fluid passes through said fluid passages in said lower bearing plate to lift said upper bearing plate off of said lower bearing plate and maintain separation between said bearing plates when the pressurized cleaning fluid is supplied to said lance so that said lance is rotatably supported.