Abstract: A device for converting solar energy into process heat has a number of heat xchanging pipes traversing a heat exchanger chamber. A first partial stream of gas to be heated is delivered to inlets of the pipes via an upper distribution chamber, and the first partial stream of gas is subsequently collected from outlets of the pipes in a lower distribution chamber. An inlet aperture of the heat exchanger chamber receives sunlight radiation and a second partial stream of gas to be heated, the second partial stream of gas flowing around the heat exchanger pipes. The heat exchanging pipes absorb the solar radiation and heat both the first partial stream flowing through the pipes and the second partial stream flowing around the pipes. The heated second partial stream is collected by a heated gas outlet conduit connected to the heat exchanger chamber.

Abstract: A rotary and/or axial slide plate valve for controlling the discharge of molten metal from a metallurgical vessel includes a refractory fixed valve part and a refractory movable valve part at least partially disposed within the fixed valve part, the valve parts having respective peripheral surfaces which establish a seal therebetween. An electromagnetic drive is provided for moving the movable valve part between open and closed positions of the valve. The electromagnetic drive may facilitate rotary and/or axial movement of the movable valve part.

Abstract: A refractory ceramic sink includes a frusto-conically shaped internal ceramic element having upper and lower end surfaces and an outer surface extending between the upper and lower end surfaces, and an external ceramic element encompassing the internal ceramic element and having upper and lower end surfaces and an inner surface extending between the upper and lower end surfaces and shaped complementary to the outer surface of the internal ceramic element. Channels are formed directly in at least one of the inner surface of the external ceramic element and the outer surface of the internal ceramic element, the channels extending from the bottom to the top of the sink.

Abstract: This invention relates to a process for the manufacture of catalysts for the reduction of nitrogen oxides in exhaust gases or for chemical air cleaning processes, in which catalyst moldings are produced from iron oxide or mixtures of iron oxide and chromium oxide and/or manganese oxide, which are reduced to grain sizes less than 2 mm, with the use of inorganic binders and sulfuric acid, and with the possible addition of activating additives.

Abstract: The invention relates to the use of manganese nodules or deep-sea ores containing manganese of more recent or older crustal layers as catalysts or for the manufacture of catalysts for the reduction of NO.sub.x components in exhaust gases or for the oxidation of NO.sub.x components and SO.sub.2 particles in exhaust gases.With the use of such catalysts, it becomes possible to reduce the NO.sub.x components in exhaust gases by using reduction agents such as NH.sub.3 at relatively low temperatures, for example, 250.degree. C. It is also possible to perform an oxidation reaction first in exhaust gases with the use of such catalysts, for example, with excess oxygen from NO to NO.sub.2.

Abstract: A hot blast stove installation for heating cold blast to form hot blast includes a plurality of hot blast stoves each alternately operable during a heating phase and a blowing phase, a cold blast main for supplying cold blast to respective of the stoves during the blowing phases thereof, and combustion air and fuel gas mains for supplying combustion air and fuel gas to respective of the stoves during the heating phases thereof. The cold blast in the cold blast main has a relatively high temperature compared to ambient temperature, for example a temperature of from 100.degree. C. to 300.degree. C. A heat exchanger is connected to the cold blast main to remove heat from the cold blast therein prior to the supply of the cold blast to the stoves, thereby reducing the men and/or maximum waste gas temperature in the stoves during the heating phase of operation thereof.

Abstract: A composite refractory member includes at least one insert formed of an oxide ceramic material having a high resistance to molten material. The insert defines a discharge opening or other molten material contacting surface. A base structure encloses and supports the insert and is formed by molding a chemically setting refractory concrete including a refractory granulate of low-iron sintered magnesia with a MgO content of over 80 weight percent. Mold cores extend into the refractory concrete during molding such that the molded structure has expansion joints which later are filled with mortar.

Abstract: Magnesia partially-stabilized zirconia ceramic materials can be prepared from "unpurified" zirconia which contains at least about 0.05 weight percent silica. Despite the relatively high silica content, a thermal shock resistant material can be produced by a firing schedule which includes heating to a top temperature at a specified rate and cooling back to room temperature at specified rates and which incorporates a thermal aging step at 1000-1200.degree. C. Differences in microstructure and monoclinic zirconia content, with consequent differences in physical properties of the ceramic material, can be attained by variations in the firing and thermal-aging schedules.

Abstract: In a process for cleaning a waste gas containing various pollutants, the exhaust gas with the pollutants is introduced directly into a reduction reactor. In the reactor, the pollutants are reduced by ammonia. The catalyst used is iron oxide material or a mixed oxide material of iron oxide and chromium oxide, or a mixture of the mixture material of the mixed oxide material and the iron oxide material.

Abstract: A hearth for use in a furnace, which comprises an upper layer of magnesia containing chromic oxide, a lower layer containing graphite and an organic bonding agent, and an intermediate layer of a mixture of the materials forming the upper and lower layers. The hearth is particularly useful in DC arc funaces, in which steel rods embedded in the bottom act as the anode. The hearth has improved service durability.

Abstract: An assembly for use in supplying a gas through a metallurgical vessel into molten metal contained therein includes a refractory supporting block to be mounted within a wall or a bottom of the metallurgical vessel. The supporting block has an inner end directed toward the molten metal and an outer end directed outwardly of the metallurgical vessel. A plurality of receiving chambers extend into the supporting block from the inner end thereof, and each of a plurality of purging bricks is fitted within a respective receiving chamber. A connecting plate is mounted on the outer end of the supporting block for connection to a source of purging gas. A plurality of channels extend through the supporting block from the connecting plate to respective of the receiving chambers and purging bricks.

Abstract: The invention relates to a process for the production of catalysts for the reduction of nitrogen oxides from exhaust gases and similar chemical air cleaning processes, in which a catalytically active material is deposited and bonded on a carrier made of metal, preferably stainless steel. The carrier is preferably in the form of a perforated metal plate, or of rib mesh, or a grid, preferably fabric, honeycombed or knitted material made of metal wire, or a similar material with a high specific surface. To simplify manufacturing and to improve the characteristics of the catalysts, the invention proposes the use of an acid which etches the surface of the metal carrier as the binder for the catalytically active material.

Abstract: A movable refractory plate assembly for use with a sliding closure unit for controlling the discharge of molten metal from a metallurgical vessel includes a movable refractory plate having therethrough a discharge opening and a movable frame for supporting the movable refractory plate in planar abutting contact with the stationary refractory plate of the sliding closure unit and movable between open and closed positions. A refractory control member is mounted for sliding movement relative to the movable refractory plate between selected positions restricting the cross section of the movable refractory plate discharge opening. An actuator slides the control member relative to the movable refractory plate between the selected positions. The control member and actuator are accessible from the exterior of the sliding closure unit. Thus, when the sliding closure unit is in the open position, only the control member need be actuated to achieve throttling of the size of the discharge opening.

Abstract: A worn and damaged refractory plate having a planar sealing surface with a sealing area at a first portion of the plate and a discharge opening extending through the plate at a second area is repaired or renewed by providing the damaged plate with a new discharge opening at the sealing area. The damaged, first-mentioned discharge opening and the wear area therearound are filled with refractory material to a level flush with the sealing surface, thereby forming a new sealing area.

Abstract: A refractory wear part for use in a sliding closure unit for a metallurgical vessel has therethrough at least one flow-through opening. The wear part is formed of a combination of gas permeable material and gas impervious material. The wear part includes at least one gas flushing zone formed of the gas permeable material and opening on a surface of the wear part. A gas duct connects the flushing zone with an external gas inlet connection. The gas duct and the flushing zone are formed as a unitary, homogeneous gas permeable structure from the gas permeable material, and such gas permeable structure is formed within a gas impervious base structure formed of the gas impervious material.

Abstract: A refractory channel connection apparatus transfers molten metal from a metallurgical vessel into a mold of a continuous casting machine formed by a peripheral groove and a casting wheel and a band covering the open side of the groove. The channel connection apparatus includes a refractory pouring tube having an inlet end connected to the discharge nozzle of the metallurgical vessel, an outlet end and a molten metal passage extending from the inlet end to the outlet end. A refractory nozzle extension is provided at the outlet end of the pouring tube, the nozzle extension having therethrough a flow through passage communicating with the passage of the pouring tube, an outer profile dimensioned to extend tangentially into the mold and to define therewith a gas seal slot, and a lower end extending into the mold to a level above the upper level of metal cast therein.

Abstract: A gas washing device for supplying gas through a metallurgical vessel to molten metal therein includes a gas permeable sink positioned to extend through a wall of the metallurgical vessel. The sink has an inner end to be exposed to the molten metal and subject to wear thereby and an outer end. A gas inlet supplies an operational flow of gas from a gas supply to the outer end of the sink. A device is operatively mounted with respect to the sink and is responsive to a temperature rise indicative of a predetermined extent of wear of the inner end of the sink by the molten metal, to reduce the flow of the gas to a reduced flow less than the operational flow upon the inner end of the sink being worn or eroded to the predetermined extent. A detector detects or measures the reduced flow of gas.

Abstract: The invention relates to a catalyst in the form of a plate for nitrogen oxide reduction in exhaust gases manufactured by molding granular Cr.sub.2 O.sub.3 or a mixture of granular Fe.sub.2 O.sub.3 with Cr.sub.2 O.sub.3 with phosphoric acid or sulphuric acid as binder, characterized by the fact that a combination is molded of separately prepared mixtures of Cr.sub.2 O.sub.3 or (Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3) with phosphoric acid as binder, and of Cr.sub.2 O.sub.3 or (Fe.sub.2 O.sub.3 +Cr.sub.2 O.sub.3) with sulphuric acid as binder.

Abstract: An apparatus for supporting a ceramic tube during firing thereof includes a base on which is mounted a lower end of the ceramic tube and supports extending upwardly from the base. A brick member is supported on the supports for grasping an upper end of the ceramic tube and for, during axial contraction of the tube during firing thereof, suspending the tube and allowing withdrawal of the lower end of the tube from the base while ensuring vertical alignment of the thus suspended tube. The brick has therethrough an opening for surrounding the upper end of the tube and defining a balancing space between the brick and the tube. Mortar fills the balancing space.

Abstract: A closure mechanism includes a conical discharge nozzle and a shielding tube fitted over the exterior of the discharge nozzle. A snug conical joint is formed by closely complementary conical surfaces of the discharge nozzle and the shielding tube. At least one ring-shaped seal is provided in such joint to prevent exterior air from entering between the discharge nozzle and the shielding tube into the interior of the shielding tube. The ring-shaped seal comprises an annular recess formed in one of the conical surfaces, thereby defining an annular chamber, and an inert gas filling such chamber.