Steam boiler having a water space traversed by a flue gas duct

Claim 2

A steam boiler having a water space, a flue gas duct traversing said water space, a muffle burner at the mouth of said flue gas duct for directing a flow of flue gas into said duct, and a plurality of tubes open to said water space and mounted in said flue duct at least in a portion of said duct directly adjacent said muffle burner and transverse to the flow of flue gas therein.

Claim 3

A steam boiler as set forth in claim 1 wherein said tubes are arranged in groups in mutually parallel planes perpendicular to the direction of flow of flue gas.

Claim 4

A steam boiler as set forth in claim 1 wherein said duct is of a quadrilateral cross-section.

Claim 5

A steam boiler as set forth in claim 3 wherein said duct includes two horizontal walls and two vertical walls with said tubes connected to said horizontal walls.

Claim 6

A steam boiler as set forth in claim 4 wherein each vertical wall includes a row of mutually adjacent finned tubes secured together in seal-tight manner, said finned tubes being open to said water space.

Claim 7

A steam boiler as set forth in claim 3 wherein said duct is of a square cross-section with a diagonal disposed in a vertical plane.

Claim 8

A steam boiler as set forth in claim 6 wherein said tubes are arranged in groups in mutually parallel planes parallel to two mutually opposite walls of said duct, said groups being disposed in an alternating criss-cross pattern.

Claim 9

A steam boiler as set forth in claim 3 wherein said duct is of a rhomboid cross-section with a diagonal disposed in a vertical plane.

Claim 10

A steam boiler as set forth in claim 8 wherein said tubes are arranged in groups in mutually parallel planes parallel to two mutually opposite walls of said duct, said groups being disposed in an alternating criss-cross pattern.

Claim 11

A steam boiler as set forth in claim 1 wherein at least some of said tubes project upwardly beyond said duct.

Claim 12

A steam boiler as set forth in claim 1 wherein at least some of said tubes include extension tubes projecting upwardly beyond said duct and angularly disposed with respect to the remainder of said tubes in said duct.

Claim 13

A steam boiler as set forth in claim 1 which further has a plurality of tubes located in a second portion of said flue duct downstream of the flow of flue gas in transverse relation to the flue gas flow, said latter tubes being in communication with a space above said water space to conduct a flow of steam from above said water space therethrough.

Claim 14

A steam boiler as set forth in claim 12 which further comprises a plurality of tubes open to said water space and located in a remaining portion of said flue duct downstream of said latter tubes in the flow of flue gas in transverse relation to the flue gas flow.

Claim 15

A steam boiler as set forth in claim 1 which further includes means for feeding feed water into said water space.

Claim 16

A steam boiler as set forth in claim 14 wherein said means includes a plurality of nozzles for forcing feed water fed into said water space into the foremost of said tubes adjacent said muffle burner.

Claim 17

A steam boiler having a water space, a flue gas duct traversing said water space in water tight relation thereto, a muffle burner coaxially mounted at the mouth of said flue gas duct for directing a flow of flue gas axially into said duct, and a plurality of tubes mounted in said flue duct at least in a portion of said duct adjacent said muffle burner and transverse to the flow of flue gas therein, said tubes being open at opposite ends thereof to said water space to conduct water therethrough in heat exchange relation to the flue gas In said flue gas duct.

Claim 18

A steam boiler having a water space, a flue gas duct traversing said water space in water tight relation thereto, a muffle burner coaxially mounted at the mouth of said flue gas duct for directing a flow of flue gas axially into said duct, and a plurality of tubes mounted in said flue duct at least in a portion of said duct adjacent said muffle burner and transverse to the flow of flue gas therein, said tubes being open at opposite ends thereof to said water space to conduct water therethrough in heat exchange relation to the flue gas In said flue gas duct.

Claim 19

A steam boiler having a water space; a flue gas duct traversing said water space, said duct including two horizontal walls and two vertical walls with said tubes connected to said horizontal walls, each said vertical wall including a row of mutually adjacent finned tubes secured together in seal-tight manner, said finned tubes being open to said water space; a muffle burner at the mouth of said flue gas duct for directing a flow of flue gas into said duct; and a plurality of tubes open to said water space and mounted in said flue duct at least in a portion of said duct adjacent said muffle burner and transverse to the flow of flue gas therein.

Claim 20

A steam boiler having a water space; a flue gas duct traversing said water space, said duct including two horizontal walls and two vertical walls with said tubes connected to said horizontal walls, each said vertical wall including a row of mutually adjacent finned tubes secured together in seal-tight manner, said finned tubes being open to said water space; a muffle burner at the mouth of said flue gas duct for directing a flow of flue gas into said duct; and a plurality of tubes open to said water space and mounted in said flue duct at least in a portion of said duct adjacent said muffle burner and transverse to the flow of flue gas therein.