Abstract: The invention relates to a cuboidal, fireproof wall brick for a heating channel of an open round-chamber kiln, having two horizontally extending setting surfaces, two vertically extending setting surfaces and two front surfaces, characterized by at least one bead-like recess in the region of at least one setting surface, the recess extending from one front surface to the opposite front surface.

Abstract: A process for reducing the oxygen content of the atmosphere in a heat treatment furnace for ceramic materials to a prescribed value comprises measuring the O.sub.2 content of the furnace atmosphere at the point in the furnace to be affected and introducing fuel gas into the furnace as a function of the measurement result in such quantities that the desired oxygen content is attained. Also described is a furnace design suitable for carrying out this process.

Abstract: In a kiln for firing ceramic workpieces, which kiln is composed of two opposed side walls and a top wall enclosing an elongate kiln chamber, and elements for introducing jets of heating or cooling gases into the kiln chamber at locations spaced along the length of the kiln, the elements are located for directing the jets produced thereby vertically in the region of the side walls of the kiln, and deflector stones are disposed at a distance from the elements for deflecting the jets and gases within the chamber transversely of the length of the kiln.

Abstract: A continuous electric tunnel furnace includes a tunnel through which articles to be fired are passed in a direction of feed. The tunnel has a length portion constituting a sintering zone. Nitrogen is introduced into the tunnel at the outlet thereof. The nitrogen stream is oriented against the direction of feed. There is further provided a gate projecting from the tunnel roof into the tunnel in the sintering zone in an orientation transverse to the direction of feed. The gate has opposite lateral bounding edges which are spaced from respective side walls of the tunnel.

Abstract: A system for conveying ceramic workpieces through a roller hearth furnace, composed of: a plurality of conveying rollers rotatably mounted one behind the other in the workpiece conveying direction with their axes of rotation parallel to one another and perpendicular to the conveying direction, and defining a common support plane for the workpieces; a plurality of drive gears each associated, and mounted coaxially, with a respective roller and provided with an axial bore having a diameter larger than that of its respective roller, with one axial end of each roller extending into the bore of its associated drive gear and being disconnectably but securely connected to its associated drive gear; and a plurality of transmission gears each mounted for rotation about an axis parallel to the axes of rotation of the rollers and each engaging an associated pair of adjacent drive gears to form a gear train in which the drive gears alternate with the transmission gears and the application of power to the gear train cause