Abstract:
A machine frame for a high-pressure roller press for receiving the rollers in the bearings of the press, including at least one first frame element below the rollers and at least one second frame element. At least one connecting element is provided for connecting the at least one first frame element to the at least one second frame element. The at least one connecting element has a U-shaped design forming two limbs. With this design, the frame can be constructed with smaller dimensions than current constructions and in one piece, because no releasable connections are necessary with this configuration of the machine frame. This design saves weight.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a machine frame for a high pressure roller press for receiving the rollers in their bearings, comprising at least one first frame element below the rollers, at least one second frame element above the rollers, and at least one connecting element for connecting the at least one first frame element to the at least one second frame element. 
     For the high pressure comminution of bulk material, it is known to pass the bulk material through the roller nip between two contrarotating rollers, where the bulk material breaks up through the application of high pressure and is pressed into flakes. In this type of comminution, the material to be comminuted is not comminuted with a shearing motion, but ideally solely by the application of high pressure to the bulk material in the roller nip, where the bulk material breaks up solely as a result of the pressure application. 
     The generated forces in the machine frame which holds together the two contrarotating rollers are in this case very high. Accordingly, it is endeavored to design the machine frame such that it is suitably stable. As a result of the stable machine frame, the high pressure roller press quickly acquires a high weight. The handling of single components of the frame of the high pressure roller press, and the transport of the roller press, are thereby made more difficult. High costs are incurred when transporting the machine parts into the district of use of the roller press, wherein the districts of use are frequently less developed mining regions remote from any infrastructure. 
     In order to reduce the weight of the entire construction, there has already been a move to statically calculate the single components individually in order thereby to save weight at the places at which this is possible. A further drawback of heavy single components of the high pressure roller press is given when the high pressure roller press is erected at sites at which there is little infrastructure available for maintaining and repairing the high pressure roller presses. In fields of use of the kind in which the service life of the roller press has considerable influence on the economic viability of the mine or of the material to be produced, there has therefore been a move toward roller press constructions which allow the rollers to be serviced or changed with little effort. 
     For the abovementioned reasons, it is desirable to constantly improve the frame construction of roller presses and, at the same time, reduce the weight and complexity. 
     SUMMARY OF THE INVENTION 
     The object of the invention is therefore to provide a machine frame for a roller press, which machine frame has a reduced own weight combined, at the same time, with high stability. 
     The object according to the invention is achieved by virtue of the fact that the at least one connecting element is of U-shaped configuration, with the formation of two side members. Further advantageous embodiments of the invention are defined in the subclaims. 
     According to the invention, it is provided that a U-shaped connecting element is arranged between a top-situated frame and a bottom-situated frame element. In this configuration, said connecting element for the two top and bottom frame parts absorbs the principal forces of the roller press construction, because the type of force guidance is geared to subjecting this connecting element only to tensile load, wherein a self-contained system of forces is constructed. This central frame element is protected against deformation by the upper and lower frame components and these serve as the assembly frame. 
     As a result of the U-shaped configuration, which is possible only by virtue of the frame design (described in greater detail below), it is possible to dispense with bolt, rivet and screw joints in the central part of the machine frame and to configure the machine frame such that it is produced solely by permanent weld joints. The middle part of the machine frame which is presented here, the connecting element, can be dimensioned smaller by virtue of the missing weakenings in the form of boreholes for bolts, rivets and screws. Hence the weight of the machine frame is reduced and handling during production is made substantially easier; thus the frame becomes cheaper and saves on transport weight. 
     Insofar as the frame has been produced solely by weld joints, the single-part construction allows a faster production method, since no precisely positioned boreholes need to be made. This frame element can be constructed lying on the ground and does not need to be turned by cranes in the course of production. 
     In one embodiment of the machine frame, it is provided that the connecting element has on the inner side of the side members at least one rail for the reception of bearings movable on this rail. The rails allow sliding of the movable roller, together with the bearings receiving the rollers, within predefined limits during operation. Furthermore, the rollers are able to be pushed or pulled out of the connecting element, so that no complex dismantling of the high pressure roller press is necessary. 
     To enable the rollers to be pushed or pulled out of the machine frame, this U-shaped element lies on the side, whereby the side members are oriented in the horizontal and a section connecting the side members is vertically oriented. For the closure of the frame, a frame section is slipped over the U-shaped, laterally open connecting element and firmly closed there. 
     The section connecting the side members receives for the application of the high pressing force a hydraulic ram, wherein the section connecting the side members has a reinforcement in order to be able to absorb the forces without mechanical failure. In order to distribute the forces evenly over the lightweight construction, a carrier plate is provided, which latter is disposed between the hydraulic ram to be received and the section connecting the side members. 
     On the side situated opposite the section connecting the side members, the connecting element is open. At this location is provided a closure element, with the aid of which a frame section can be used to close the connecting element to create an annular frame. The closure elements, in the concrete case hammerhead-shaped ends of the side members of the connecting element, here absorb the forces of the hydraulic ram on the side situated opposite the hydraulic ram. 
     The force is here transmitted from the hydraulic ram to one of the bearings of the rollers, and from there via a plurality of elements to the closure element. The rollers are not fixedly disposed in the machine frame, however, but can perform compensating motions. To this end, it is provided that at least one side member of the connecting element has on the inner side a rail for the reception of bearings movable on this rail. On this rail, the bearings, in predefined stretches, can perform compensating motions to enable larger elements to pass through the roller nip without blocking the rollers. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is explained in greater detail with reference to the following figures, wherein: 
         FIG. 1  shows a high pressure roller press having the machine frame according to the invention in a perspective view, 
         FIG. 2  shows the entire machine frame of the high pressure roller press having mutually offset frame components, 
         FIG. 3  shows the machine frame according to the invention in a side view. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In  FIG. 1 , a high pressure roller press  10  is portrayed in a perspective view, comprising the multipart machine frame  20 , the rollers  31  and  32 , and the four bearings  33 ,  34 ,  35  and  36 . The multipart machine frame  20  is comprised, for its part, of a first frame element  41  below the rollers  31  and  32 , a frame element  42  above the rollers  31  and  32 , and two connecting elements  43  and  44 . These connecting elements  43  and  44  each form two side members  45  and  46 , and  47  and  48 , which are connected to one another by connecting sections  49  and  50 . The side members  45  and  46 , and  47  and  48 , of the connecting elements  43  and  44  serve, for their part, as the base for slide rails for the movably installed bearings  33 ,  34 ,  35  and  36 , wherein, according to the design of the high pressure roller press  10 , the bearings  33  and  34  disposed in the foreground of the diagram are configured as fixed bearings and the bearings  35  and  36  disposed in the background of the diagram are configured as movable bearings. The bearings  33  and  36 , which are accommodated within the connecting elements  43  and  44 , are forced by hydraulic rams  51  and  52  into the middle of the machine frame counter to the force of the grinding stock flowing through the nip  60  between the rollers  31  and  32 . The forces of the hydraulic rams  51  and  52  subject the side members  45  and  46 , and  47  and  48 , of the connecting elements  43  and  44  to tensile load, since the abovementioned forces are transmitted from the respectively, in the diagram, front connecting sections  49  and  50 , via the bearings  33  and  36  and the roller  32 , the nip  60  between the rollers  31  and  32 , from there to the roller  31  and from here, in turn, to the bearings  34  and  35 . This roller  31 , in this embodiment configured as a fixed roller, with the bearing  34  configured as a fixed bearing and the bearing  35  configured as a movable bearing, is supported against a respective frame section  61  and  62 , which frame sections are both respectively slipped over the respectively upper side member  46  and  47  and received and closed off in a closure element  63  and  64 , in which the frame sections  61  and  62  are closed below the respectively bottom side members  45  and  48  and are supported on the hammerhead-shaped ends of the side members  45 ,  46 ,  47  and  48 , which ends serve as a closure element  63  and  64 , and  65  and  66 . Within the entire frame, the connecting elements  43  and  44  form, in conjunction with the frame sections  61  and  62 , a self-contained system for the absorption of forces exerted by the hydraulic rams  51  and  52 . 
     Particular to this construction is the fact that the overall structure of the machine frame is in one part and turns out to be particularly light, because the parts which are subjected to tensile load and form a self-contained system of forces have no screw joints or rivet joints. Because these are free from screw joints and rivet joints, the top and bottom chords and beams of the side members  45 ,  46 ,  47  and  48  can be dimensioned smaller. In order to change the bearings  33 ,  34 ,  35  and  36  or and/or the rollers  31  and  32 , it is sufficient to remove respectively one of the frame sections  61  and  62  and pull out the bearings, together with the rollers  31  and  32  supported by the bearings  33 ,  34 , and  36 , rearward in this perspective. The lower and upper frame elements  41  and  42  lend the entire machine frame  20  the necessary stability against torsions and ensure that the overall construction of the machine frame suffers no deformation through parallel displacement. Stays  75  and  76  behind the closure elements  61  and  62  hold together the respectively two side members  45  and  46 , and  47  and  48 , of the connecting elements  43  and  44  and ensure that the frame weight does not put load upon the bearings, so that, during operation of the high pressure roller press  10 , the bearings, together with the rollers  31  and  32 , can perform compensating motions which are as low in friction as possible. Without the stays  75  and  76 , the weight of the upper frame element  42  would, during operation, put load upon the sliding plane of the bearings  33 ,  34 ,  35 , and  36 , whereby the compensating motions would be made more difficult and the wear upon the slide rails  81 ,  81 ′,  82  and  82 ′ would turn out to be unnecessarily high. 
     In order to be able to absorb the high forces of the hydraulic rams  51  and  52 , it is provided that the connecting sections  49  and  50  respectively have a reinforcement  49   a  and  50   a  and, where necessary, also a carrier plate  71  and  72 , to prevent mechanical failure of the connecting sections  49  and  50  under the load of the hydraulic rams  51  and  52 . 
     In  FIG. 2 , that part of the machine frame  20  which is fundamental to the invention, namely the at least one connecting element  43  and  44 , is illustrated by dashed and solid lines. As opposed to the representation in  FIG. 1 , in this figure the hydraulic rams  51  and  52 , the rollers  31  and  32 , frame sections  61  and  62 , and stays  75  and  76  present in the vicinity of the frame sections  61  and  62  are blanked out. In order to better demarcate the two connecting elements  43  and  44  from the frame elements  41  and  42 , the frame elements  41  and  42  are in dashed representation, while the connecting elements  43  and  44  are represented with continuous lines. 
     In comparable frame constructions, the frame components, which are made up of individual sections and are similar to the connecting elements  43  and  44 , are connected to one another by bolt, rivet and screw joints. The construction of this central component of the machine frame  20  is hence complex and expensive. However, it has previously been necessary to construct this frame component by using releasable joints to enable the rollers  31  and  32  to be released, or even lifted out from the frame for maintenance purposes. Since this frame is open on the, in this view, rearward-pointing side, the rollers can be pushed or pulled out rearward by displacement of the bearings  33 ,  34 ,  35  and  36  on the rails  81  and  81 ′, which rails are visible in this view. Thus it is not necessary for the connecting element  43  to be made removable, and assembly elements such as screws and rivets are able to be dispensed with in this construction. Without weakening of the beams and upper and lower chords of the connecting elements  43  and  44 , the steel beams, from which the connecting elements  43  and  44  are produced, can be designed in smaller dimensions, which, given the size of the frame, which weighs a few tonnes, allows an appreciable weight saving. This saving makes itself felt not only in respect of transport, but also in respect of assembly, because the connecting elements can be constructed by welding and handling during production thereby becomes easier. 
     Finally, in  FIG. 3 , one of the connecting elements  43  and  44  is represented in a side view. The U-shape, lying on the side, is clearly apparent, in which U-shape the connecting element  43  forms two, during use, horizontally lying side members  45  and  46 , which are connected to each other by a, during use, vertically oriented, connecting section  49 . On the inner side of the section  49  is disposed a carrier plate  71  for the reception of the hydraulic cylinder  51  represented in  FIG. 1 . During operation of the roller press, the bearing  33  accommodated in the connecting element  49  ( FIG. 1 ) slides to and fro on the rail  81  within the scope of the possible compensating motion of the roller  32 . For the removal of the rollers  31  and  32  ( FIG. 1 ), it is provided that the rollers are moved to the right out of the connecting element  43 , the connecting element  43  here being represented open. The frame is closed by a frame section  61  (likewise shown in  FIG. 1 ), which is slipped from above over the upper side member  46  and is lowered into the receiving bay  85 . The frame section  61  here also reaches over the lower side member  45  and is closed off with the aid of the fixing element  86 . By contrast, the forces of the rollers and of the hydraulic ram  51  ( FIG. 1 ) are transmitted from the frame section  61  (not illustrated here) to the hammerhead-shaped closure elements  63  and  64 . 
     In order to transmit the forces of the roller system optimally to the hammerhead-shaped closure elements  63 ,  64 ,  65  and  66 , it is provided that, optionally, the frame sections  61  and  62  are not fixedly connected to the side members  45  and  46 , and  47  and  48 . In this way, the frame sections  61  and  62  can transmit their force evenly to the hammerhead-shaped closure elements  63 ,  64 ,  65  and  66  in the dynamically loaded machine frame  20 . 
     As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art. 
     REFERENCE SYMBOL LIST 
     
         
           10  high pressure roller press 
           20  machine frame 
           31  roller 
           32  roller 
           33  bearing 
           34  bearing 
           35  bearing 
           36  bearing 
           41  frame element 
           42  frame element 
           43  connecting element 
           44  connecting element 
           45  side member 
           46  side member 
           47  side member 
           48  side member 
           49  section 
           50  section 
           51  hydraulic ram 
           52  hydraulic ram 
           60  nip 
           61  frame section 
           62  frame section 
           63  closure element 
           64  closure element 
           65  closure element 
           66  closure element 
           71  carrier plate 
           72  carrier plate 
           75  stay 
           76  stay 
           81  rail 
           82  rail 
           85  receiving bay 
           86  fixing element