Abstract: A tunnel kiln useful for burning vertically perforated green bricks, includes a furnace chamber; a plurality of tubular burners for heating the furnace chamber, with the burners defined by longitudinal axes which extend essentially in a vertical direction; and a transport device for so transporting green bricks in raster-like spaced-apart relationship in a travel direction through the furnace chamber that the perforations of the green bricks are oriented in a common direction. Each of the burners has a nozzle body formed with orifices for combustion gases, with the orifices defined by longitudinal axes which extend substantially in a direction of the perforations, wherein the nozzle body is positioned within a spacing between confronting end faces of neighboring green bricks.

Abstract: A tunnel kiln useful for burning vertically perforated green bricks, includes a furnace chamber; a plurality of tubular burners for heating the furnace chamber, with the burners defined by longitudinal axes which extend essentially in a vertical direction; and a transport device for so transporting green bricks in raster-like spaced-apart relationship in a travel direction through the furnace chamber that the perforations of the green bricks are oriented in a common direction. Each of the burners has a nozzle body formed with orifices for combustion gases, with the orifices defined by longitudinal axes which extend substantially in a direction of the perforations, wherein the nozzle body is positioned within a spacing between confronting end faces of neighboring green bricks.

Abstract: A process for the production of articles consisting of ceramic material comprises the steps of: extruding a starting material which is of a plastic consistency and contains clay to form a string having at least one longitudinal channel; drying, firing and cooling the string; passing a gaseous medium, for example air, through said at least one longitudinal channel of the string or sections thereof; and subsequently dividing the string or sections thereof into individual articles. There is also provided an apparatus for carrying out the process.