Central heating furnace

Claim 1

A central heating furnace comprising an outer casing enclosing a closed system of tubes communicating with each other and containing a heat-carrying medium, said tube system having parts placed along at least the major areas of the inner walls of said casing, and burner means included in said furnace for heating said heat-carrying medium, said burner means having a nozzle means for generating a flame directed substantially vertically downwardly, said tube system further including a tube spiral having its length axis directed substantially in the same direction as said nozzle means and being shaped to surround said flame, said tube system includes a plurality of said tube positioned side by side to form planes having horizontally directed tubes along a bottom of said casing and along a top of the rear part of said casing and having vertically directed tubes along all sides, excluding a top of said front part and openings for discharging flue gas and enabling soot removal, the tube plane directly inside the vertical front side of said rear part extends downwardly far enough to leave only a lower opening for the flue gases to pass above the bottom tube plane, and between said vertical tube plane behind the front side of said rear part and the vertical back tube plane is inserted a vertical intermediary tube plane which is parallel to the two firstmentioned vertical planes and extending from the bottom tube plane and up to a level high enough to form a second flue gas opening below the top tube plane, said vertical intermediary tube plane having side facing said vertical covered with a tight plate, extending upwardly to the top of said vertical intermediary tube plane.