Abstract: The invention relates to a method of and apparatus for dry grinding a granular material in a grinding tube mill (1) having a final grinding compartment (2) and one or more preceding grinding compartments (3) containing grinding bodies. The material, after having passed through the preceding compartment or compartments (3), is discharged through openings (6) in the mill (1) and is divided into a fine and a coarse fraction in a separator (9). The coarse fraction is returned to the preceding compartment or compartments (3), and the fine fraction is fed to the final compartment (2). The ground material is discharged by flowing over a dam ring (12) from the final compartment (2). Any grinding bodies carried with the overflow are separated by a sieving diaphragm (13) from the material and returned to the final compartment (2). The invention also relates to the granular material ground according to the method of the invention.

Abstract: A method is disclosed for manufacturing pulverous or granular material in a plant supplied with raw material, for example, cement raw meal, including a kiln for burning the raw material to be treated therein, a cooler coupled after the kiln for cooling the product treated in the kiln, a first preheater coupled before the kiln and heated with kiln exit gases, and a second preheater heated with spent cooling air. According to the preferred embodiment, the method comprises the steps of feeding all of the raw material to the second preheater, conveying all of the raw material preheated in the second preheater to the first preheater, and returning to the cooler for reuse therein, all of the cooling air cooled in the second preheater. A unique plant is disclosed for practicing the method of the invention. The method and plant promote fuel economy and eliminate or at least minimizes dedusting requirements in the manufacture of such pulverous or granular material.

Abstract: A method and apparatus for measuring the temperature of hot fluids (1) in environments involving thermal radiation. The apparatus comprises at least one radiation-protected measuring body (4) constituting one end of a heat-tube (2) having a working temperature below the fluid (1) temperaure to be measured. The other end of the heat-tube (10) is connected to one end of a heat-conducting rod (8); the other end of which is kept cool by cooling means (11). The apparatus is equipped with temperature measuring means (12, 14) for measuring the temperature of the heat-tube as well as the temperature at two points along the heat-conducting rod. There can be more than one measuring body.

Abstract: A rotary kiln having a plurality of outlets for passage of material from within the kiln to associated cooler tubes mounted in use in planetary fashion around the outlet end of the kiln. Each kiln outlet has a tubular support to which the inlet end of the associated cooler tube is attached, and a steel reinforcing ring within the support. Insulation is provided between the ring and the support and the ring is lined internally with a wear-resisting ceramic material. An annular collar is formed of the same material as the ring and extends radially beyond the joint between the support and the kiln shell. The collar--which is bolted to the kiln shell--is insulated from both the support and the kiln shell and is coated with a wear-resistant ceramic material.

Abstract: A rotary kiln having a live ring is supported by a pair of rollers on shafts. The ends of each shaft are supported by bearings carried at the ends of a weigh beam having a rocking bearing so that the rollers can tilt to follow changes in the slope of the kiln. To allow the rollers to follow any axial movement of the live ring, upon thermal expansion or contraction of the kiln, the rocking bearing is slidable on a partly cylindrical segment.

Abstract: The present invention is directed to a method for selective purification of gases. The method comprises feeding an exhaust gas containing a solid impurity and a gaseous impurity to a separator. A substantial portion of the solid impurity is separated. Then, the partially-purified gas is fed to a spray dryer. That gas is sprayed with an absorption agent to separate gaseous impurities. Then, the further, partially-purified gas is fed to another separator to separate remaining solid impurity. An exhaust gas which is substantially free of solid and gaseous impurities and fly ash having a desired quality are recovered.

Abstract: An apparatus and a method is disclosed for removal of a cardanically supported slide shoe of a slide shoe bearing which supports a rotary tube mill disposed within a slide ring. The apparatus includes two horizontal track joists supported on upright members and oriented parallel to the axis of rotation of the mill. Each track joist supports an end of the slide shoe which preferably has horizontal surfaces at its ends for cooperating with the track joists. The apparatus also includes a plurality of screw jacks disposed between each of the track joists and its respective upright support members. The screw jacks can be independently operated to raise the slide shoe free of its cardanic support, preferably a ball and socket-type of joint. A carriage means disposed between an end of the slide shoe and a respective track joist facilitates displacement of the slide shoe along the track joists.

Abstract: A discharge electrode is disclosed for producing ion emission in an electrostatic precipitator. The electrode includes a rigid cylindrical tubular member having a plurality of protrusions extending outwardly therefrom. The protrusions preferably have rounded free end portions and are formed either by individual rods integrally attached to the member or by one or more wires attached to the surface of the member and having folds which are selectively spaced apart to provide the desired dispersion of the ion emission. The wires may also be embedded in depressions defined in the surface of the member. The invention also pertains to an improved electrostatic precipitator incorporating the inventive discharge electrode.

Abstract: A material grinding tube mill having a composite diaphragm (5) at the outlet end of a grinding chamber (3). The diaphragm comprises a coarse grate (6) facing the grinding chamber (3) for retaining grinding bodies in the chamber (3), and, on the side of the grate (6) remote from the chamber, a sieving screen (7) for sieving the ground product. The coarse grate has a plurality of openings (20) which constitute substantially the effective open area of the coarse grate. Disposed within the space defined between the coarse grate (6) and the sieving screen (7) are guiding members (21, 22) to guide coarse particles backwards to the grinding chamber (3) through one or more apertures (19) in the coarse grate (6) which allows free passage of the coarse particles.

Abstract: A method is disclosed for operating a cement kiln plant in which impurities in the form of alkalis are present in vapor form in the hot dust laden gases generated in the kiln. According to the method, a portion of the hot dust laden kiln gases are directed upwardly through a first riser pipe which communicates with the kiln exit gas opening and thereafter the dust particles are separated from the gases and directed to the bottom portion of a second riser pipe having its lower end open to the atmosphere. Relatively cold atmospheric air is directed upwardly through the second riser pipe so as to contact the kiln dust particles separated from the by-passed kiln gases of the first riser pipe thus permitting the kiln dust particles to be cooled by the cold air while causing the air to be heated and providing its further use e.g. in a preheater.

Abstract: A method of firing a rotary kiln for the production of cement clinker is disclosed. The method includes the step of directing at least a major portion of the amount of fuel necessary for firing the kiln so as to be brought into direct contact with hot cement clinker in a precooling zone of the rotary kiln. There is further disclosed an apparatus for the production of cement clinker from cement raw meal. The apparatus comprises an inclined rotary kiln having a precooling zone in the lower end portion thereof in which cement raw meal collects and means for directing a jet of fuel into direct contact with hot cement clinker in the precooling zone of the material downstream end of the rotary kiln.

Abstract: An arrangement is disclosed for supporting a rotary drum such as a rotary kiln resting upon a foundation. The support arrangement includes a weigh beam positioned in a horizontal plane and pivotally supported on the foundation. At least two carrying beams are poitioned in a generally horizontal plane adjacent said weigh beam and each of the carrying beams are pivotally mounted at one end thereof to the foundation and flexibly supported at another end thereof by the weigh beam. A roller for rotatably supporting the rotary drum is supported on the carrying beams by bearings. The support arrangement thereby effects a substantial mechanical equalization of the forces exerted on the roller during the rotation of the drum to warping and twisting of the drum.

Abstract: Apparatus for measuring the particulate content of a gaseous medium includes temperature control devices for permitting application to both hot gases and cold, wet gases. Specifically, the apparatus comprises an exhaust nozzle for coupling with a duct through which gas passes; a filter housing including a filter; an exhaust tube, having a heat exchange passage therein, connected between the nozzle and the filter housing; an exhaust device; a conduit for coupling a heat exchange medium to the exhaust tube passage; and a controllable heating element for heating the heat exchange medium in the conduit between a source and the exhaust tube. In preferred embodiments, the heating element is arranged around the filter housing in heat exchange relationship with the conduit, providing temperature conditioning of both the medium and the filter housing in a very compact apparatus. In a specific example of this embodiment, the heating means and the conduit are arranged in interlaced helices about the filter housing.

Abstract: A vertical roller mill is disclosed for grinding material. The roller mill includes a rotatable grinding table at least one grinding roller resting upon the grinding mill, a pressure frame secured to the grinding roller and a housing which surrounds these elements. A guide mechanism pivotally connected between the pressure frame and the housing resiliently restrains movement of the pressure frame with respect to the housing and thereby reduces the transmission of forces from the pressure frame to the housing.

Abstract: A plant is disclosed for heat treating pulverous raw material such as cement raw meal prior to a final sintering process in a rotary kiln. The plant includes a rotary kiln having an upper material inlet end portion for the reception of preheated cement material and a lower material outlet end portion for exiting the final sintered kiln product. A multi-stage cyclone string preheater having at least a first stage for receiving the cement raw meal has a last stage communicating with the upper material inlet end portion of the kiln. A smoke chamber connects the upper material inlet portion of the kiln with the preheater, and a scoop chamber connects the kiln with the smoke chamber. The scoop chamber is adapted to receive preheated, at least partially calcined raw material from at least one preheater stage other than the last stage.

Abstract: A method is disclosed for burning alkaline raw materials in an inventive rotary kiln plant. According to the method, cold atmospheric air is introduced tangentially into a circular chamber mounted either within, or adjacent to, the raw material inlet end of the kiln such that a circulating stream of cold air is produced in the chamber around a stream of exhaust gases passing from the kiln to the chamber. A part of the exhaust gases are thereby cooled by the cold air, and alkali vapors therein are condensed out of, and onto, dust particles in the exhaust gases. The alkaline-coated dust particles are thus subsequently discharged from the chamber. The invention also relates to a rotary kiln plant for practicing the inventive method.

Abstract: A method is disclosed for heat treating pulverulent or granular raw material such as cement meal. Raw material is directed to at least two multi-stage preheater strings, the first string communicating with the kiln by a smoke riser pipe and the second string having a calciner positioned at its lower end portion. The raw material directed to the first preheater string is divided into two divisional flows with the first divisional flow comprising substantially the maximum amount of material which can be substantially completely calcined by hot gases exiting the kiln. The first divisional flow of raw material is directed toward the upper material inlet end portion of the kiln so as to be entrained by the hot gases exiting the kiln, and the hot kiln gases and entrained material are directed to the first preheater string. The second divisional flow is directed to the second preheater string where it is calcined either alone or with raw material directed to the second string.

Abstract: A method is disclosed for manufacturing white cement wherein cement clinker is burnt in a kiln and prior to discharge from the kiln the clinker is contacted with a reducing agent such as fuel oil. The method further comprises discharging the hot cement clinker from the discharge portion of the kiln to a movable clinker supporting means such as a rotatable conveyor and quenching the cement clinker simultaneously with the discharge thereof from the kiln by subjecting the clinker to a spray of cooling water in a manner such that a major portion of the quenching water evaporates substantially immediately following the quenching.

Abstract: A method is disclosed for burning alkali-containing raw materials such as cement raw meal in a plant having a multiple string cyclone preheater, each string containing at least two cyclone preheater stages, a kiln, and a cooler unit for cooling the burnt material from the kiln by means of air which is subsequently divided into two streams, one stream being passed through the kiln and a kiln string of the preheater, the other stream being passed through a calciner and up through the calciner cyclone string of the preheater. According to the invention, the flow of material from the penultimate preheater cyclone stage of the kiln string is directed to the calciner, at least a part of the material from the penultimate cyclone stage of the calciner string is directed to the lowermost cyclone stage of the kiln string, and at least a remaining portion of the material from the penultimate cyclone stage of the calciner string is passed to the calciner.

Abstract: A rotary kiln plant is disclosed having a rotary kiln and a cooler system having a plurality of cooler tubes mounted in planetary fashion about the rotary kiln. Each cooler tube has an inlet end portion which communicates with the rotary kiln for reception of the material to be cooled and a rearward end portion having an outlet end for exiting the cooled material. First support means is positioned adjacent the inlet end portion of the cooler tube and second support means is positioned adjacent the outlet end portion of the cooler tube so as to retain the axis of the cooler tube substantially parallel to the axis of rotation of the kiln.