Abstract: Dustlike and/or finely divided solids which arise in the purification of flue gases, in particular from refuse incineration plants, are subjected to a thermal treatment. In this case, the said solids are fed to a filter device along a predetermined transport path by a gas stream having at least the thermal treatment temperature. After the filtration, the solids can be subjected to a thermal post-treatment. The thermal treatment can serve to destroy halogenated, in particular aromatic, hydrocarbons, to remove ammonia or other volatile constituents.

Abstract: For reducing nitrogen oxides in the flue gases of a firing plant, fresh ammonia water, i.e. an aqueous solution of ammonia (NH.sub.3), is introduced into the flue gas flow. For achieving a high degree of separation of the nitrogen oxide a superstoichiometric addition of ammonia (NH.sub.3) is necessary. Most of the excess ammonia is washed out in the wet washer (6). A liquor, e.g. milk of lime (Ca(OH).sub.2), is dosed into the wash water in a connecting line (10) to a stripping column (11), so that a pH-value above 9.5 is obtained. The now physically dissolved ammonia (NH.sub.3) is desorbed from the wash water in the stripping column (11). The steam/ammonia mixture passing out of the stripping column (11) is condensed in a condenser (17) and the condensate in the form of ammonia water is admixed to the fresh ammonia water in feed line (3). As a function of the nitrogen oxide reduction, approximately 10 to 50% of the fresh ammonia water can be saved.

Abstract: Solid residues obtained in flue gas purification, in particular flue dusts, are disposed in an environmentally compatible and economical manner by acid extracting heavy metals from the residues, precipitating the heavy metals from the extract, separating the precipitate from the mother liquor, subjecting the precipitate containing heavy metals to mechanical stress during which procedure the water contained in the precipitate is released and the precipitate itself is resuspended, and then adding a hydraulic binder to the resuspended precipitate containing heavy metals and/or to the extracted residues separately from one another. The binder-containing mixture can be used to form moldings which, after hardening, are employed for the erection of boundary walls in a landfill, Additionally or alternatively, the plastic binder-containing mixture can be introduced in the form of layers into preformed landfill spaces, where it then hardens.

Abstract: During melting in an electric melting furnace of iron products such as pig iron, scrap iron, directly reduced iron pellets, and various alloy metals, or mixtures of the foregoing having greatly varying impurities, solid carbon dioxide is led over the melting hearth shortly before, during, and after charging. Explosive burning of the combustible constituents is thus prevented in that the oxygen is displaced during the charging operation by the expanding gaseous carbon dioxide produced. The method makes possible electric steel production with reduced accumulation of dust and fumes in that formation thereof is largely eliminated directly at the source. By cutting down on the high volumes of gas and gas temperatures occurring during charging without carbon dioxide, substantially smaller filter installations are needed, whereby the amount of savings on investment and operating costs economically compensates for the cost of the carbon dioxide utilization.

Abstract: The invention concerns a manhole cover with a frame (1) and a grating (3) or cover fitting flush with the frame (1). In order to secure the cover (3) in such a way that it can be easily removed and put back in place, a one-piece securing element (4a) is attached to the frame (1), the securing element (4a) having a locking element (7) at the end of a tab-like retaining element (6) extending obliquely upwards. The locking element (7) engages against a locking surface (9) at the bottom of a recess (8) in the surface of the grating (3) or cover. To unlock the manhole cover, the locking element (7) can be pulled away from the locking surface (9) with a special tool, e.g. a pair of pliers, the retaining element (6) being bent elastically. The securing element (4a) is mounted on the frame (1), embracing shoulders (5a, 5b) so that it is secured by a snap-in connection. The securing element can also be attached to the cover or grating and engage against a locking surface on the frame.

Abstract: In order that higher demands on the purity of the separated liquid can be satisfied, a cleaning plant (12) having wash chambers (13a,b) for the cleaning of the filter plates (8) is arranged in longitudinal direction alongside of a filter press (1). By means of a transport device (30) having a displacement device (32) which is moveable along rails (31a) and is equipped with a raisable and lowerable gripper (37) which can be engaged via pawls with filter plates (8), the filter plates, after the opening of the filter press (1), are transported one after the other into the cleaning plant (12), sprayed in one of the wash chambers (13a, b) with simultaneous drawing off of the air or subjected to an immersion bath, possibly disinfected or impregnated, dried and transported back. By the development of the cleaning plant (12) with two wash chambers (13a, b), idle paths of the displacement device (32) are substantially avoided.

Abstract: The components forming the layers of a composite pipe are successively introduced into a rotary drum (1). Initially, a plastic reinforcing layer (8), including a fibre reinforcement, is introduced into the drum, the ends of the drum (1) being bounded by rings. A concrete core layer (16) is then introduced and the length of the core layer (16) is shortened relative to that of the drum (1) by shaping rings fixed to the drum ends. The shaping rings are then replaced by other shaping rings (20, 21) so that, on either side of the core layer (16), two annular spaces (22, 23) are formed which are filled by a socket material (24, 25) of the same composite as the reinforcing layer (8). Thus, at one pipe end a socket end (28) is formed and at the other pipe end a spigot end (30) is formed, each such end being located within the composite pipe wall thickness. After introducing a second reinforcing layer (26), the production of the composite pipe is completed.

Abstract: A multi-loop control system and a method for using the control system to even out the generation of heat produced by a refuse incineration plant. The quantity of steam generated is controlled as a primary controlled variable and the oxygen content of the flue gas is controlled as a secondary controlled variable. This method makes it possible to improve other parameters in operating a refuse incineration plant.

Abstract: A covering for a ground opening includes a frame in which a cover can be inserted. The frame has a recess for receiving a retaining web shaped onto the edge of the cover. A niche with a sloping bearing surface is formed in the frame at a distance from the recess. The cover has a cam. When the cover is in the closed position, a supporting wall provided on the cam formed on the cover edge rests on a bearing surface of the frame, so that, on closing the cover, the later is moved in the direction of the recess and assumes a locked position. Thus, the cover is held in a clearance-free manner in the frame.

Abstract: In a cover-frame assembly for a manhole or the like a locking device is provided, which comprises a closing member having at least two horizontal arms and a mounting rod provided with a bearing and actuating device. The mounting rod and the bearing and actuating device are located in a bore having a widened bore portion, whereby a shoulder is formed, on which is supported a bearing surface of the bearing and actuating device. The ends of the arms each project into a guide link, which is shaped on the inner flange of the frame. The guide link has an inclined flank, by means of which the arms are increasingly elastically deformed. In the closed position of the locking device, the arms engage in locking recesses provided on the end of each inclined flank. This leads to a self-closure with pre-tension.

Abstract: A locking device for a covering comprised of a frame and a cover includes arms, which are inserted in depressions or bores formed in the frame and/or cover, whereby they undergo elastic deformation and consequently form a frictional engagement with the cover. The free end each of the arms project beyond an inner flange of the frame and form there a positive connection between the arms and the inner flange. This results in a simple, but effective connection between the cover and the frame, without requiring machining of the arms or depressions.

Abstract: Nitric oxides are removed from flue gases by the spraying-in of a liquid containing a reducing agent. The atomizing agent necessary for forming the liquid into individual droplets and for the transportation of the droplets is introduced together into the central feed pipe for the liquid before it is branched to the individual spray points.

Abstract: The ground water drain comprises a frame and a grating inserted in the frame. The grating has a central bar and a plurality of crossbars arranged normal to the central bar. Holding portions are provided in the frame over its support for the grating. Projecting portions formed on some crossbars project into the holding portions when grating is inserted into the frame. For the insertion of the grating, at least one projecting portion on one side of the grating is inserted into the corresponding holding portion and subsequently the opposite side of the grating is pressed down. The projecting portions have sloping faces which snap into the holding portions of the frame while the central bar is simultaneously elastic bent. Therefore the grating is positively secured in the frame and even when using an elastic material for the grating the latter cannot be moved to such an extent by the traffic travelling over it that it could jump out of the frame.

Abstract: The manhole covering comprises a casing, a base frame and an adjusting device. A two-part base frame has a plurality of bores, which are aligned with pockets located in the base part of the casing. In each pocket is inserted a screw nut, into which is screwed and secured the lower end of a threaded bolt extended through the assigned bore of the base frame. The base frame is adjusted in height and slope by a pair of nuts. The adjustment of a particular slope is made possible due to the shape of the bores, which widen to either end and by convexly curved washers cooperating with the bores at their ends. The screw connection of the base frame constitutes a positive connection, which prevents breaking out of the base frame even in the case of a high, eccentric force application to the manhole covering.

Abstract: In constructions with a relatively limited ground height, e.g., bridges, flat roofs, etc. the foundation or earthwork is covered with a sealing sheet, which extends up to a drain casing or frame. To avoid a return flow of liquid below the sealing sheet and into the foundation, in the arrangement according to the invention, the edge portion of the sealing sheet is laid downward over the wall of the frame or the casing. A locking frame is placed on the edge portion of the sealing element. The locking frame can additionally be secured in position by vertical threaded bolts and is used for pressing the edge portion of the sealing sheet onto the frame or onto the casing.

Abstract: A cover assembly for an opening comprises a frame and a covering. At least one elastically deformable, rod-like closing member is provided on the covering. The closing member forms one part of a locking device, the other part of which is a retaining member which includes a groove provided in the frame, in which can engage a closing finger located on the closing member accompanied by the elastic deformation of the closing member. Thus, in a simple manner, the covering is positively secured in the frame.

Abstract: A frame for forming coverings for ground openings and method of assembling such frame are disclosed. Frame parts for assembling the frame are provided at their ends with connecting lugs, which are arranged at different levels. On fitting the frame, the two frame parts are juxtaposed, their connecting lugs are arranged in spaced superimposed manner and are interconnected by screw couplings. For positively interconnecting the frame parts, the frame is turned upside down, and a liquid, pasty or granular filling material is filled into a bore on the underside of the upper connecting lug. The filling material also flows into the bore of the screw coupling, which is covered by a washer. Following the solidification of the filling material, the frame can either be transported in this state or in a disassembled state and can be then reassembled in the same way.

Abstract: An elongated generally cylindrical iron shaft is cast as a single piece. The shaft has a longitudinal axis and has a centrally disposed longitudinal hollow channel extending completely therethrough along the axis. The shaft has a plurality of transverse channels extending outwardly from the longitudinal channel completely through the shaft to the outside thereof and communicating with the longitudinal channel. Each transverse channel has the shape of a nozzle. The outside openings of the transverse channels are spaced apart and are disposed along a helical path on the outer surface of the shaft. The helix has an axis coincident with the longitudinal axis.

Abstract: A covering includes a cover and a frame into which the cover is inserted. A supporting surface of the cover and a cooperating bearing surface of the frame each have a surface inclined with respect to the cover plane. These surfaces are partial peripheral surfaces of a sloping cylinder and/or a sloping cone bounded by sections. As a result the partial surfaces have along their circumferences a different inclination with respect to the cover plane. Therefore the cover can only be inserted in the frame in a specific position. Since as a result of this the same surface positions of the cover and the frame always rest on one another, in the case of such coverings a tight closure can be achieved with a circular or oval opening.

Abstract: A covering for an opening in road surfaces, squares or the like comprises a frame and a cover. The cover has a conical, downwardly and inwardly inclined contact surface by which the cover is supported on a bearing surface provided on a support flange of the frame. The bearing surface is also conical and inwardly inclined. At the bearing surface are provided spaced, circumferentially distributed wedge-shaped grooves, which cooperate with lugs on the cover. By means of the inwardly and downwardly inclined surfaces of the lugs and grooves, a self-centering of the cover is obtained. The centering is guided by the lugs. Thus, even in the case of high traffic loads, the cover is not moved from its position.