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: 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: 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: The electrically weldable sleeve has a tubular sleeve member, heating elements arranged on the inner wall of the sleeve member and terminals for an energy supply. A material recess in the form of slots is provided in the edge zone of the boundary area of the heating element. This makes it possible to completely utilize the shrinkage reserve imparted to the sleeve member during the production of the sleeve, so that it is effective up to the solidification of the core of the melting zone. It also completely compensates for the volume contraction of the material linked with the solidification of the melting zone, so that the occurrence of cavities is reliably avoided. Corresponding to the axial flux of force represented by lines, the material recesses must be located at a point, which leads to no weakening of the sleeve member portions decisive for assembly and operation.

Abstract: In a burner, particularly for use in a drum of a combustion furnace or incinerator for flowable, pump-deliverable waste materials, a lance is provided for introducing the fuel and a nozzle is placed on the end thereof. The lance can be surrounded by a first uncooled lining, which essentially comprises two tubular, coaxial jacket parts. The first lining is surrounded by a second lining, which once again comprises two jacket parts. The combustion air for the additional fuels in the incinerator (e.g. barrels, etc.) is introduced into the incinerator between the two linings, while the burner air enters in the vicinity of the nozzle in the first lining between the two jacket parts. Thus, important media for the actual combustion process can be directly introduced to the burning point within the incinerator via the burner.

Abstract: A level measuring sensor is arranged at the start of the straining zone in the perforated belt press and this in particular measures the level change and then regulates the flocculant inflow. In order that the level in the straining zone is stabilized, the perforated belt press must operate in the overflocculation zone. If the flocculant inflow is reduced to the technically possible operating limit, the dry substance content of the filter cake has an optimum value. Thus, the optimization of the control of the operation of the perforated belt press can be reduced to a relatively simple measurement of a level or the time changed thereto.

Abstract: The connecting member has a sleeve body and a resistance heating wire embedded therein with terminals to a power supply. By heating the resistance heating wire, a welding area between the sleeve member is plasticized and welded. For checking the weld quantity, an indicator is provided, which comprises a cavity having a piston with an indicator pin movable therein in the welding area. During welding the material which becomes plastic as a result of the welding pressure is forced into the cavity, so that the indicator pin covered prior to welding is forced out through a passage and is consequently visible and tangible. As the travel of the piston is limited by a cover at the end of the cavity and the distance from the bottom of the cavity to the welding area can be selected corresponding to the desired welding pressure, the end position of the exiting indicator pin corresponds to a temperature and pressure range necessary for completely satisfactory welding.

Abstract: The spigot end of one pipeline element is inserted in the socket end of the other pipeline element and is sealed by a gasket. To the end face of the socket end is connected a thrust preventing ring, which is secured by claws to part of a collar. A retaining ring engages on the inner surface of the thrust preventing ring and its inner face is provided with a tooth system, which is fixed to the surface of the spigot end. Between the end face of the socket end and the retaining ring is provided a thrust ring, which exerts a pressure on the retaining ring. By means of in each case one packing element on the side of the thrust preventing ring facing and remote from the socket end, said ring is located in a sealed and consequently corrosion-proof zone. Thus, the socket joint is secured without any modification to the pipeline elements.

Abstract: An auxiliary apparatus with a trough or tank, to which the incineration residues are supplied by means of a drop shaft, a movable piston for moving the incineration residues from the trough to a discharge chute and at least one opening for inspecting and maintaining the trough arranged in a side wall at the latter and provided with a door. A plate, which can be inserted through the opening in the trough, is positioned in front of the front face of the piston. The plate is held on the chute walls by locking devices and is supported on the piston by adjusting mechanisms. The front face of the plate assembled from two parts is, for the same width, twice as high as the front face of the piston. The adjusting mechanisms are constructed as an adjustable arrangement of push rods or as pneumatic or hydraulic lift cylinders.

Abstract: A roller is provided with ribs directed outwardly from its face which permit the formation of cavities between the circumferential surface of the roller and the screen belts entrained thereon so that continuous channels are formed on the circumferential surface of the roller which conduct the filtrate axially outwards. The ribs are hollow tubular members having an opening along the surface of the roller which captures additional liquid, preventing it from falling back onto the belt, and allowing it to be conducted off and drained by allowing the liquid to flow laterally only.

Abstract: A socket for joining the ends of conduits, pipe or the like comprising a body of thermoplastic material in which is embedded, in a helical coil, a resistance wire strand formed of a plurality of juxtaposed individual thin wire elements, the wire elements being in part spaced from one another, to form gaps allowing for expansion of or movement of the wire elements without overall expansion or movement of the strand.