Furnace with heat storage elements

Furnace and boiler unit having a housing (18), a fire box (2) within the housing, and a combustion gas chamber (4) located in the housing, a water jacket at the interior of said housing, a passage to exhaust the combustion products from the combustion chamber, openings (6) formed in the housing and providing access to the combustion gas chamber, and doors (6', 36', 44', 46') closing off the openings, and comprising

• heat storage elements (10) located in the combustion gas chamber (4, 34) and positioned therein in the path of flow of the combustion gases, said heat storage elements (10) having a cross section which is smaller than the cross section of the largest opening (6;
• 26, 37, 44, 46) providing access to the combustion gas chamber (4, 34) to allow introduction and removal of the heat storage elements (10) into and from the combustion gas chamber (4, 34), a carrier (14, 74, 114, 114', 214, 414),
• and a plurality of heat storage elements (10) secured to the carrier, the carrier being of metal, each heat storage element (1) comprising a metallic housing (16) formed with openings (12) in at least a portion thereof, and a compact mineral material of high thermal capacity located within said housing (16), the plurality of heat storage elements being located along the lateral side walls of the combustion gas chamber, the perforations in the metallic housings of the heat storage elements, at least in part, facing the inner wall of the housing.