An upper furnace portion (A) includes side walls (12, 14) extending along its lower edge. A dimensionally stable furnace hearth (B) is movably mounted adjacent the furnace lower edge and is displaced a small distance from the side walls, such that the hearth is movable without engaging the side walls, yet sufficiently close that relatively little heat tends to pass between the hearth and the side walls. The hearth includes a metal base plate (20) to which a plurality of vertically extending anchoring plates (26) are connected and supported by gussets (30). A plurality of wires (28) are welded to the anchoring plates and extend into peripheral refractory elements (24) which are integrally molded to the wires and the anchoring plates. A plurality of refractory slabs (34) and bricks (36) are supported by the base plate and are disposed within an area defined by the peripheral refractory elements to define a workpiece supporting surface. A plurality of expansion joints (32) permit the peripheral refractory elements to be constrained against outward or radial movement, and a plurality of expansion joints (32 ) accommodate circumferential or longitudinal expansion. Further expansion joints (38, 40) extend within the peripheral refractory elements and through the refractory slabs and bricks (34, 36) to permit thermal expansion thereof.
A movable car bottom furnace in which premature failure of the metallic components of the movable car bottom are avoided by moving a hinged lower portion of the side wall into engagement with the refractory portion of the car bottom whereby only a refractory to refractory contact is made between the walls and car bottom, with all said contact occurring at a level above the uppermost level of the metallic components of the car bottom.
A tunnel kiln for firing molded ceramic green products includes a gate for feeding a kiln car into and out of the kiln. The gate located at low temperature parts of the kiln includes side walls made of a stainless steel having inclined surfaces and a ceiling made of a stainless steel and having inclined surfaces toward the side walls. The tunnel kiln further includes sand seals at connections between the side walls and the ceiling and receiving bases provided under lower ends of the side walls for receiving pyrolytically decomposed products. The side walls are formed with exhaust ports communicating with the receiving bases so that the pyrolytically decomposed products flow along the inclined surfaces of the ceiling and the side walls are once collected in the receiving bases and exhausted through the exhaust ports of the side walls to the outside of the kiln. With this arrangement, defective ceramic products due to decomposed products attached thereto are completely eliminated.
A truck running on a rail laid in the firing furnace comprises a metallic frame body and a refractory base assembled thereon. At least an outside portion of the refractory base is comprised of car-top bricks each provided at its inward lower part with a foot portion and refractory base bricks located beneath the car-top bricks each provided with an engage portion engaging with a foot portion.
A rotary hearth furnace for use in the iron and steel industry comprises a furnace (12, 112) with plan in the shape of an annulus, closed at the bottom by a rotary hearth (14, 114), lined at the top with refractory material (15, 115), and a base (28, 128; 30, 130) of the furnace (12, 112). Said hearth (14,114) comprises a plurality of sectors of an annulus (17, 117; 17', 117'), all the same as one another and connected to form an annulus, complementary to that of the internal plan of the furnace (12, 112), which rotate around the central axis of the annulus, by means of two concentric sets of wheels (26, 126) arranged according to two circumferences, set at equal instances, with supports (25,125), fixed to the base (28) or below the hearth (114), complementary to two circular rails (20, 120), fixed respectively below the hearth (14) or the base (128). According to the invention, both said sets of wheels (26, 126) and said two rails (20, 120) are positioned in such a way as to have an equal load distribution.
Furnace for the treatment of ore on a rotary hearth, including a toroidal chamber, a rotary hearth and drives for the rotary hearth, the hearth being arranged on a supporting frame fitted with guides means and motion-supports; the drives are at least partly connected to the said guides and/or to the motion-supports means.
