Abstract:
A slag remover for discharging combustion residues of an incineration plant comprises a trough, which has a trough housing having two side walls, which define the trough width, and having a trough bottom, and which is intended to collect the combustion residues evacuated from a combustion chamber of the incineration plant. The trough further comprises at least two push rams for pushing the combustion residues out of the trough, and a shaft rotatably mounted in two shaft bearings and on which at least one drive lever cooperating with a cylinder-piston unit and at least two output levers connected to respectively one of the push rams are disposed in a rotationally secure manner. The cylinder-piston unit is here designed such that the push rams move back and forth between a retracted position and an extended position. The drive lever is disposed between two output levers.

Description:
INTRODUCTION 
       [0001]    The present invention relates to a slag remover for discharging combustion residues of an incineration plant, and to the use of the slag remover for a waste incineration plant. 
       BACKGROUND 
       [0002]    In the field of waste incineration , slag removers serve to discharge from the incineration plant, in the course of the incineration, the residues (slag) which cannot be further incinerated. 
         [0003]    Slag removers generally comprise a drop shaft, via which the combustion residues fall from the combustion chamber into a water-filled trough. From this, the combustion residues are pushed by means of a push ram over an expulsion chute or expulsion path, whence they can be transported onward in dumpable form. 
         [0004]    One example of a slag remover is described, for instance, in DE-A-2539615. Here a discharge piston, which pushes into the expulsion chute the slag which falls onto the trough bottom, is articulately connected at its rear end to one or more thrust cranks, which are seated in a rotationally secure manner on a shaft which is rotatably mounted in bearings in the side walls of the trough. Disposed in a rotationally secure manner on both ends of the shaft, which ends project beyond the side walls, are lever arms, which respectively cooperate with a hydraulic piston-cylinder unit, 
         [0005]    A drawback with such a slag remover is that, for instance, when slag is present which is conveyable only with great effort and this is distributed inhomogeneously over the trough cross section, load torques, which necessitate appropriate dimensioning of the shaft, are generated. Moreover, the moments of force which act on the respective bearing are in this slag remover relatively large, which is not conducive to optimal force transmission. 
         [0006]    Since the lever arms must in most cases be removable, in a slag remover such as that according to DE-A-2539615, in which the force flow goes via the bearings disposed in the side walls, keyways are generally provided. However, as a result of the accompanying weakening of the shaft or lever arm, the mechanical stability thereof is impaired. Moreover, the fitting of keyways or corresponding keys is relatively complex and expensive. 
         [0007]    A further slag remover is disclosed, for instance, in EP-A-0363645, according to which two push rods, which are mounted rotatably on a lever by means of a joint, are present. The lever is here configured as a two-armed lever, between whose arms a pivot shaft is disposed. As opposed to DE-A-2539615, according to EP- A-0363645 joints are prevented from dipping into the water fill of the trough. The problems with respect to the generation of load torques in the shaft persist, however. 
       SUMMARY 
       [0008]    An object of embodiments of the present invention thus lies in providing a slag remover that avoids the generation of load torques and enables optimal force transmission to the push ram. 
         [0009]    In embodiments, the slag remover comprises a trough, which is intended to collect the combustion residues evacuated from a combustion chamber of the incineration plant, as well as at least two push rams for pushing the combustion residues out of the trough. 
         [0010]    Each of the push rams is connected to an output lever. The output levers are disposed in a rotationally secure manner on a shaft rotatably mounted in two shaft bearings. 
         [0011]    Also disposed on the shaft is a drive lever, which cooperates with a cylinder-piston unit. The latter is designed such that the push rams move back and forth between a retracted position and an extended position. 
         [0012]    In such embodiments, the drive lever is now disposed between two output levers. In contrast to the previously known slag removers, in which the drive levers are disposed on the ends of the shaft which project beyond the side walls, the arrangement of the drive and output levers can serve to ensure that, even given the presence of combustion residues which are conveyable only with great effort, the shaft is not exposed to load torques. Moreover, the arrangement of the drive and output levers enables optimal force transmission from the cylinder-piston unit to the push rams, which, inter alia, is associated with the fact that the force flow, in contrast to said previously known slag removers, does not go via the shaft bearings. As a result of the optimization of the force transmission or the reduction in load torques which is attainable according to embodiments of the invention, the shaft can be dimensioned relatively slim. 
         [0013]    Optimal reduction or elimination of load torques is obtained, in particular, when the slag remover comprises just a single drive lever and just a single cylinder-piston unit cooperating therewith. This yields the advantage, in particular for this embodiment, that an adjustment of various cylinder piston units, or a monitoring that these are running in parallel during operation, is fully dispensed with, whereby very simple and efficient operation is enabled. 
         [0014]    With a view to optimal force transmission, the drive lever is preferably disposed symmetrically between the output levers. 
         [0015]    Preferably, the slag remover has precisely two output levers. Any higher number is also conceivable, however, with preference, in particular, for an even number of drive levers, since a symmetrical arrangement of the drive lever between the output levers is thereby enabled. 
         [0016]    In general, the shaft extends at least over the trough width, wherein the shaft bearings are disposed on the side walls. Preferably, the drive lever is here disposed substantially midway between the shaft bearings, whereby the force acting on the shaft bearings is thus equally distributed on both shaft bearings. 
         [0017]    Embodiments of the present invention allow the shaft to be mounted in bearing pedestals detachably fitted to the trough housing, which makes access to the shaft or to the lever disposed thereon very much easier. Moreover, embodiments of the present invention allow the at least one drive lever and the output levers to be welded to the shaft, whereby very high mechanical stability is ensured. 
         [0018]    A removal of the shaft, or of the levers seated thereon, can be realized very easily by a detachment of the bearing pedestals; a splitting of the shaft, or complex keyways, as are necessary in conventional slag removers—such as that according to DE-A-2539.615—can thus be dispensed with in embodiments of the present invention. 
         [0019]    As mentioned, the slag remover generally has a drop shaft, through which the combustion residues fall into the trough. In its retracted position, the push ram is generally disposed in a region lying (viewed in the expulsion direction) behind the drop shaft. Preferably, the end face of the push ram here lies in at least approximately the same vertical plane as the rear wall of the drop shaft, which wall faces away from the expulsion direction, 
         [0020]    Generally the cylinder-piston unit and the drive lever are also disposed in a region lying (viewed in the expulsion direction) behind the drop shaft. 
         [0021]    A particularly preferred drive geometry is obtained when, during operation, the cylinder-piston unit, or the force vector emanating therefrom, is oriented at an angle of less than 20°, preferably less than 10°, particularly preferably less than 5° with respect to the horizontal, since optimal force transmission efficiency from the cylinder-piston unit to the push ram can thereby be obtained. The horizontal here corresponds to the longitudinal axis of the trough running at right angles to the orientation of the drop shaft. 
         [0022]    In order to ensure that the cylinder-piston unit, even if oriented substantially horizontally, is present in a space separated from the trough interior, the trough, according to a particularly preferred embodiment, is present, at least in some areas, in the form of two longitudinally running, mutually separate trough channels, wherein the cylinder-piston unit and/or the drive lever are/is disposed, at least in some areas, in the interspace between the trough channels. Since the cylinder-piston unit and the drive lever, viewed in the expulsion direction, are generally disposed in a region lying behind the drop shaft, the trough, according to a preferred embodiment, is present only in this region in the form of trough channels. In the expulsion direction, the trough channels generally open out into a trough basin, by which the trough channels are fluidically connected to one another. 
         [0023]    From said water-filled trough basin, which is disposed beneath the mouth of the drop shaft and in which the combustion residues are collected, the interspace, or the cylinder-piston unit or drive lever disposed, at least in some areas, therein, is preferably separated off by means of a partition plate. All in all, the interspace is sectioned off from the trough interior by those channel walls of the trough channels which face the vertical longitudinal axis and by the partition plate. 
         [0024]    Through the arrangement of the cylinder-piston unit in the interspace, a very simple removal from below is enabled. 
         [0025]    According to a further embodiment of the invention, on a first of the side walls is disposed a first water tank comprising a freshwater connection and a fill level apparatus, and on the second of the side walls is disposed a second water tank comprising a dirty water connection and an overflow. As opposed to the background art, in which the drive levers are disposed on the ends of the shaft which project beyond the side walls, according to embodiments of the invention water tanks can thus be fitted on the side wall without the drive arrangement having to be taken into account in the arrangement and dimensioning of said water tanks. Rather, the above-described arrangement can result in the cylinder-piston unit, and, in particular, the (hydraulic) cylinder thereof, being disposed outside the water tank, which corresponds to a further preferred embodiment of the invention. 
         [0026]    The water tanks have a lid, which is preferably dimensioned such that simple cleaning of the interior by means of a water hose is possible. Generally, both water tanks have a slit, disposed in their lower region, for the water flow. Filling takes place into one of the two water tanks and is regulated via the fill level apparatus. 
         [0027]    As mentioned in the introduction, the slag remover is suitable, in particular, for a waste incineration plant, since, specifically in waste incineration, very inhomogeneous combustion residues can arise, which, in conventional drive arrangements, can lead to the aforementioned load torques. The invention thus further relates to the use of the slag remover for a waste incineration plant. 
         [0028]    Typical trough widths of a slag remover for a waste incineration plant range from about 2 m to 2.5 m. Larger trough widths, preferably up to about 3.2 m, are also conceivable, however. The mouth of the drop shaft into the trough has typically in the longitudinal direction of the trough an extent of about 1 m to 1.5 m. According to the purpose and objective, the dimensions can be readily adapted by the person skilled in the art who has acquired knowledge of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    Embodiments of the invention are illustrated in detail with reference to the appended figures, wherein: 
           [0030]      FIG. 1  shows a longitudinal section through a slag remover according to an embodiment of the invention with the push rams in the retracted position; 
           [0031]      FIG. 2  shows a longitudinal section through the slag remover according to  FIG. 1  with the push rams in the extended position; 
           [0032]      FIG. 3  shows a perspective view of a part, comprising the drive arrangement, of the slag remover according to an embodiment of the invention; 
           [0033]      FIG. 4  shows a detail of the slag remover according to an embodiment of the invention from a perspective view from obliquely below; and 
           [0034]      FIG. 5  shows a detail of the slag remover according to an embodiment of the invention from a perspective view from obliquely above. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0035]    The slag remover  2  shown in  FIG. 1  is generally disposed in the region of the outlet of a combustion chamber (not represented) of an incineration plant. From the combustion grate of the combustion chamber, the non-combustible combustion residues (slag) fall into a vertically running drop shaft  4 , which can flare out in the shape of a funnel in the direction of the outlet of the combustion chamber. 
         [0036]    The drop shaft  4  opens out into a water-filled trough  6 , which is disposed on a supporting structure having appropriate pillars  7  and extends in a longitudinal direction running at right angles to the orientation of the drop shaft  4 . In this trough  6  are collected the combustion residues falling through the drop shaft  4 . The trough  6  has a trough housing  8  comprising two side walls  10   a,    10   b,  which define the trough width and respectively run parallel to the longitudinal direction in a vertical plane, and a trough bottom  14 , which is arched below the drop shaft mouth  12 . In the side walls  10   a,    10   h  of the trough  6  is respectively provided a sealable opening  16 , which allows access to the trough interior for cleaning purposes. 
         [0037]    In the expulsion direction, i.e. in the direction of the output of the slag remover, the trough  6  is adjoined by an expulsion chute  18  having an ascending expulsion path  20 . 
         [0038]    The drop shaft  4  has a (viewed in the expulsion direction) front wall  22  and rear wall  24 . As can be seen, in particular, from  FIG. 4 , in a region lying (viewed in the expulsion direction) behind the drop shaft  4 , the trough  6  is present in the form of two separate trough channels  26   a,    26   b,  which, running obliquely downward, open out into a trough basin  28  disposed directly beneath the drop shaft  4 . 
         [0039]    The trough channels  26   a,    26   b  are delimited, on the one hand, (on the side respectively facing away from the longitudinal center plane) by the respective side wall  10   a  and  10   b  of the trough  6  and, on the other hand, by a respective channel wall  30   a  and  30   h  facing the longitudinal center plane and running parallel thereto. Between the trough channels  26   a,    26   b  or between the channel walls  30   a,    30   b  is configured an interspace  32 . The interspace  32  is separated off from the trough basin  28  by a partition plate  34 . In the shown embodiment, this has a vertical region  34 ′ and an adjoining horizontal region  34 ″, as can be seen, in particular, from  FIGS. 1 and 2 . 
         [0040]    In the region behind the drop shaft  4 , a shaft bearing  36   a  or  36   b  in the form of a bearing pedestal is respectively detachably fastened to the respective side wall  10   a,    10   b  by means of appropriate fastening means. In these shaft bearings  36   a,    36   b  is rotatably mounted a shaft  38 , which extends over the trough width. 
         [0041]    Seated in a rotationally secure manner on the shaft  38  are two output levers  40   a,    40   b,  which are respectively articulately connected to a push ram  42   a  or  42   b.  Midway between the output levers  40   a,    40   b,  a drive lever  44  is disposed in a rotationally secure manner on the shaft  38 , which drive lever is connected by its end facing away from the shaft to the piston  46  of a cylinder- piston unit  48 . Generally, both the drive lever  44  and the output lever  40   a,    40   b  are welded to the shaft  38 . 
         [0042]    As is evident, in particular, from  FIG. 3 , the drive lever  44  is disposed on the shaft  38  midway between the output levers  40   a,    40   b  and runs, together with the cylinder-piston unit  48 , in the vertical longitudinal center plane of the trough  6 . 
         [0043]    The cylinder-piston unit  48  is disposed in the interspace  32  between the trough channels  26   a,    26   h  and is mounted in the channel walls  30   a,    30   b  via an axle  50 , as can be seen, for instance, from  FIG. 4 . When the piston  46  is retracted, the cylinder-piston unit  48  is arranged substantially horizontally, i.e. parallel to the longitudinal axis of the trough  6 . 
         [0044]    As is explained in detail further below, during operation of the slag remover a torque is applied to the shaft  38  through the extension of the piston  46  of the cylinder-piston unit  48 , which is easily pivotable out of the horizontal, by means of the drive lever  44 , whereby the push rams  42   a,    42   b  are moved by means of the output levers  40   a,    40   b  from a retracted position according to  FIG. 1  into an extended position according to  FIG. 2 . 
         [0045]    The push rams  42   a,    42   b  have a bend and are divided by this into a front arm segment  52  and a rear arm segment  54 . Attached to the free end of the push rams  42   a,    42   b  is, in the shown embodiment, a push shield  56 , which has an end face  58  and a cover  60 , which latter runs in a plane obliquely to the plane of the end face and rests on the front arm segment  52 . 
         [0046]    In the shown embodiment, moreover, on the lower edge of the end face  58  of the push shield  56  is disposed a sliding shoe  61 , which rests on a slideway  62  formed by the trough bottom  14 . 
         [0047]    In addition, the trough  6  has a flap  64 , whose free end  64 ′ rests on the cover  60  and whose edge  64 ″ lying opposite the free end is situated above the bottom edge  24 ′ of the rear wall  24  of the drop shaft  4 . In the retracted position of the push rams  42   a,    42   b,  the end face  58 , the flap  64  and the rear wall  24  of the drop shaft  4  lie substantially in the same vertical plane. 
         [0048]    As can be seen, in particular, from  FIG. 3 , the push shield  56  has on each side, moreover, a further cover plate  66   a,    66   b  assigned to the respective side wall  10   a  and  10   b  of the trough  6 . 
         [0049]    The movement of the push rams  42   a,    42   b  by means of the drive arrangement can be seen, in particular, from  FIGS. 1 and 2 . Here, a torque is applied to the shaft  38  through the extension of the piston  46  of the cylinder-piston unit  48  by means of the drive lever  44 , whereby the push rams  42   a,    42   b  are moved by means of the output levers  40   a,    40   b  from a retracted position into an extended position. The combustion residues collected in the trough  6  are hereupon pushed out of the trough into the expulsion chute  18  or onto the expulsion path  20 . 
         [0050]    During the forward movement, i.e. the movement of the push rams  42   a,    42   b  and thus of the push shield  56  in the direction of expulsion, the flap  64  pivots upward, whereupon it rests with its free end  64 ′ unbrokenly on the cover  60 . Combustion residues present in the drop shaft  4  hereupon deposit themselves on the cover  60  or on the flap  64 . 
         [0051]    Penetration of combustion residues into the space lying (viewed in the direction of expulsion) behind the end face  58  is here effectively prevented by the cover  60  or the additional cover plates  66   a,    66   b.  Similarly, the flap  64  serves to prevent combustion residues from possibly getting into the space lying behind the flap and thus into the trough channels  26   a,    26   b.    
         [0052]    During the rearward movement of the push rams  42   a,    42   b  from the extended into the retracted position, the trough bottom  14 , in the region of the trough basin  28 , is opened up again for combustion residues falling in from above. The flap  64  hereupon pushes the combustion residues deposited on the cover  60  over the front edge of the cover, so that said combustion residues are deposited in front of the end face  58  on the trough bottom  14 . As a result of the combustion residues, which in the retracted position of the push rams  42   a ,  42   b  are present in front of the end face  58 , or the resulting blockage effect, the combustion residues present in the expulsion chute  18  are prevented from sliding rearward. 
         [0053]    The combustion residues pushed out of the expulsion chute  18  by a renewed stroke of the push rams  42   a,    42   b  are finally transported away for further use or for dumping. 
         [0054]    As can be seen, in particular, from  FIG. 4 , only that end region  6 ′ of the trough  6  which is facing away from the direction of expulsion is present in the form of trough channels  26   a,    26   b,  which, in the shown embodiment, have a substantially rectangular cross section. The interspace  32  which is configured between the trough channels  26   a,    26   b  and encompasses the cylinder-piston unit  48  is separated off from the water-filled trough, on the one hand, by the channel walls  30   a,    30   h  facing the longitudinal center plane and, on the other hand, by a partition plate  34 . The vertical region  34 ′ of the partition plate  34  here runs in a vertical plane, which, viewed in the direction of expulsion, runs behind the vertical plane of the rear wall  24  of the drop shaft  4 . 
         [0055]    That region of the trough  6  which lies behind the drop shaft  4 , and also the interspace  32 , are covered by means of a covering hood  68 , as is shown, in particular, in  FIG. 5 . This is equipped with openings  70 , which allow access both to the trough channels  26   a ,  26   b  and to the interspace  32  also from above. 
         [0056]    It is further conceivable to dispose (not shown) on a first of the side walls  10   a  or  10   b  a first water tank comprising a freshwater connection and a fill level apparatus, and on the second of the side walls  10   b  or  10   a  a second water tank comprising a dirty water connection and an overflow. 
         [0057]    The shown arrangement of the drive lever  44  in relation to the output levers  40   a,    40   b  allows optimal force transmission to the push rams. Load torques, such as can be generated, in particular, when two cylinder piston units are present, are effectively avoided. The use of bearing pedestals also allows relatively simple fitting and removal of the shaft  38 . The prospect of welding the output levers  40   a,    40   b  and the drive levers  44  to the shaft  38  enables expensive keyways to be dispensed with.