Method for sorting fiber stock, especially for manufacturing paper, and sorting apparatus for the performance of such method
BACKGROUND OF THE INVENTION 
     The present invention relates to a new and improved method of, and apparatus for, sorting fiber stock, especially for the fabrication of paper, wherein the fiber stock together with a liquid is moved by a rotor located within a housing or container, the throughput or throughpassing fiber stock being withdrawn from the housing through a screen or sieve. 
     As concerns the sorting apparatus of the present development, which is suitable for the performance of the method aspects, such embodies a housing or container equipped with a screen or sieve and a rotor operatively associated with such screen or sieve. This rotor is provided with blades or vanes which move along or over the screen. 
     There are known in this technology many different constructions of sorting apparatuses which function according to such general method aspects, and, for instance, serve for reclaiming fiber stock obtained from waste paper and for separation of surface-like or areal contaminats, such as, for instance, plastic foils, from the mass of waste paper. U.S. Pat. No. 3,942,728, granted Mar. 9, 1976 is illustrative of one such type of sorting apparatus or stock pulper. 
     SUMMARY OF THE INVENTION 
     It is a primary object of the present invention to provide a new and improved method of, and apparatus for, sorting fiber stock, especially for the fabrication of paper, which in contrast to the heretofore known equipment possesses a spate of advantages. 
     Another and more specific object of the present invention aims at providing an improved method of, and apparatus for, sorting fiber stock in a most simple manner, with very modest energy requirements, within a pressureless, and thus, relatively inexpensive housing or container, wherein pieces of foils or the like contained in the fiber stock mass are only slightly comminuted if at all and can be effectively separated. 
     Yet a further important object of the present invention is concerned with an improved fiber stock sorting method and apparatus which is equally beneficially useful for the processing of fiber stock obtained from waste paper and intended for the fabrication of new paper, as well as for the fiberizing and sorting or fractionating of new fiber stock. 
     Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the inventive method is manifested by the features that the fiber stock is propelled by the action of the rotational movement of the rotor out of the region of the rotor and transferred into an air chamber or space forming a turbulence chamber which is located externally of the region of the rotor. Thereafter, such fiber stock again arrives at the region of the same rotor or another rotor, by means of which the fiber stock is again propelled away. 
     As alluded to above the invention is not only concerned with the aforementioned method aspects, but concerns an improved construction of sorting apparatus for the performance thereof. Generally speaking, the sorting apparatus of the present development is manifested by the features that the housing together with the screen or sieve possesses the shape of a vat or trough at the lower region of which the screen or sieve forms a partial surface of a body of revolution. This body of revolution has a substantially horizontal or inclined axis and is arranged at the region of the lengthwise axis of the shaft of a rotor equipped with at least one blade or vane. This blade or vane extends close to the region of the screen or sieve and serves to clear or clean such screen. Externally of the region of the rotor there is arranged an air chamber or space forming a turbulence chamber. The mass containing the fibers can be propelled by the rotor into such turbulence chamber or space, and thus can be subjected to intensive turbulence or agitation within such turbulence chamber. 
     Regarding both the inventive method and sorting apparatus both have common thereto the feature that the fiber stock mass is propelled away by a rotor and subjected to intensive turbulence or agitation. During such time as the fiber stock mass is intensively agitated the fibers which have been released or de-fiberized from the fiber stock mass are simultaneously withdrawn through the screen or sieve and form the throughput or throughpassing stock, in this case the so-called good stock. Parts which have not been de-fiberized or dissolved and which are contained, for instance, in waste paper, are eliminated. 
     According to a relatively simple embodiment of the method the fiber stock is upwardly or elevationally propelled by the rotor and again drops back on to the same rotor, and the throughput stock is withdrawn through the screen or sieve beneath the rotor. 
     However, it is also possible for the fiber stock to be propelled by another rotor back onto the first-mentioned rotor. 
     With the sorting apparatus of the present development it is possible for the rotor to contain, apart from the mentioned blades or vanes which serve for clearing or cleaning the screen, also shorter blades or vanes which serve to propel the mass of the fiber stock. In principle, the clearing or cleaning blades also can undertake the task of propelling the mass of the fiber stock. However, it has been found that shorter blades or vanes which move in spaced relationship from the screen or sieve, propel the mass at a steeper angle against the screen or sieve, something which is beneficial for the sorting or classifying operation. 
     The blades or vanes, and specifically the clearing blades or vanes, as well as also the propelling blades or vanes, can extend perpendicular to their direction of movement. In this case other means must be provided to ensure for the axial movement of the fiber stock mass within the equipment, for instance the housing could be arranged at an inclination to achieve this effect. 
     However, it also would be possible for at least one of the blades or vanes to be inclined with respect to the direction of movement in such a manner that it brings about a movement or conveying of the fiber stock mass in the axial direction of the rotor. 
     According to a preferred embodiment a deflection element providing a deflection surface can be arranged above the rotor. This deflection surface serves to deflect the fiber stock mass propelled away from the rotor back into the axial region of the rotor. Due to this measure the motion of the agitated mass is deflected in such a manner that it can be propelled at a favorable angle against the screen or sieve. 
     For this purpose the deflection surface can be domed or arched in the direction of movement of the fiber stock mass, and such deflection surface can be equipped with guide ribs or ledge members for such fiber stock mass. 
     Preferably, at the ejection side of the rotor there can be arranged for movement adjustable guide ribs or ledges. These adjustable guide ribs, depending upon their angle of attack or adjustment angle with regard to the direction of movement of the fiber stock mass, can cause or promote movement of such fiber stock mass in the axial direction of the rotor. By adjusting such guide ribs or ledges there can be beneficially controlled the throughput velocity of the fiber stock mass through the equipment. 
     Discharge openings or apertures for water can be distributively arranged at the housing or container in the lengthwise direction of extent thereof. In this manner the fiber stock mass which is contained within the equipment can be flushed and diluted. 
     For the same purpose the shaft of the rotor can be constructed to be hollow and connected with an infeed line or conduit for water. In this case the hollow rotor shaft is provided with discharge or outlet openings for the water flowing through such hollow shaft. 
     According to a further embodiment of the invention a further rotor can be located within the housing. The lengthwise axis of this further rotor can extend essentially parallel to the lengthwise axis of the first rotor. 
     This further rotor can be advantageously located in the air or turbulence chamber or space. Due to these measures there is obtained a particularly intensive agitation and processing of the fiber stock mass. 
     In all of the aforementioned constructional embodiments it is possible for the housing or container to also be provided with an infeed vat or trough having an overflow edge or weir. This infeed vat is arranged above the housing containing the rotor and extends essentially parallel to its lengthwise axis. In this way there is desirably obtained a uniform distribution of the infed materials along the length or axial extent of the equipment, whether such infed materials are constituted by the water together with the fiber stock mass or simply the water alone. 
     Moreover, the infeed vat or trough can extend over more than one half of the axial extent of the housing. When processing inputted fiber stock masses of lower stock density it is possible to thus obtain a flushing thereof with a suitable liquid, typically water, and the infeed of additional water only then is required in a subsequent section of the equipment. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and objects other than those set forth above, will become apparent when consideration is give to the following detailed description thereof. Such description makes reference to the annexed drawings wherein throughout the drawings there have been generally used the same reference characters to denote the same or analogous components, and wherein: 
     FIG. 1 is a schematic longitudinal sectional view through an exemplary embodiment of sorting apparatus useful for the performance of the inventive method; 
     FIG. 2 is a cross-sectional view, on an enlarged scale, taken substantially along the line II--II of the arrangement of FIG. 1; 
     FIG. 3 is a corresponding cross-sectional view of the arrangement of FIG. 1, taken substantially along the line III--III thereof; 
     FIG. 4 is a fragmentary sectional view of part of the arrangement of FIG. 2, depicting a modified construction of a deflection element forming a deflection surface; 
     FIG. 5 is a cross-sectional view, analogous to the showing of FIG. 3, but depicting a different exemplary embodiment of equipment; 
     FIG. 6 is a front view of a different embodiment of sorting apparatus and analogous to the showing of FIG. 1; 
     FIG. 7 is an end and partially sectional view of the arrangement of FIG. 6, taken substantially along the line VII--VII thereof; 
     FIG. 8 illustrates a modified construction of the sorting apparatus depicted in FIG. 6; 
     FIGS. 9 and 10 respectively depict two schematic sectional views portraying two further constructions of the inventive sorting apparatus; and 
     FIG. 11 is a schematic illustration of one of the blades or vanes which is positioned at an inclination with respect to its direction of movement. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Describing now the drawings, it is to be understood that only enough of the construction of the sorting apparatus of the present development has been shown therein so as to enable those skilled in the art to readily understand the underlying principles and concepts of the present development, while simplifying the showing of the drawings. Turning attention now to such drawings, the exemplary embodiment of sorting apparatus depicted in FIGS. 1 to 3 will be seen to comprise a housing or container 1 possessing the shape of a vat or trough. This housing or container 1 is provided with a partial surface 2 of a cylinder possessing a lengthwise or cylinder axis A which may be substantially horizontal or inclined. In the embodiment under discussion the partial surface 2 is defined by essentially a semi-cylinder and is formed by a screen or sieve 3. Merging with this partial cylinder surface 2 are vertical walls 4 and 5 which in conjunction with the screen or sieve 3 form the vat or trough 1a of the housing 1. Arranged coaxially to the cylinder or lengthwise axis A of the screen or sieve 3 is a rotor 6 which is equipped with a hollow shaft 7 as well as blades or vanes 8, 9 and 10. The blades or vanes 8 extend in close proximity to the screen or sieve 3 and serve for clearing or cleaning the screen 3 during rotational movement of the rotor 6 about its lengthwise axis which is the same as the cylinder or lengthwise axis of the housing 1 and its screen 3. The blades 8 define a surface of revolution of the rotor 6. Arranged above the surface of revolution defined by the blades 8 of the rotor 6 is an air chamber or space serving as a turbulence chamber 11 and which is closed at its top or upper region by a deflection element 12 defining a deflection or guide surface. In the illustrated exemplary embodiment the deflection surface 12 is domed or arched in such a manner that the fiber stock mass which is elevationally or upwardly propelled by the action of the rotor 6 and sliding along such deflection surface 12 can again slide back towards the region of the lengthwise axis A of the rotor 6. 
     As will be apparent by reverting to FIGS. 1 and 3, the deflection surface 12 is equipped with guide rib or ledge members 13 for the fiber stock mass which is propelled away from the rotor 6. These guide rib members 13, in the illustrated exemplary embodiment, are situated in planes which are disposed essentially perpendicular to the lengthwise axis A of the rotor 6. However, these guide rib members 13 also could be arranged at an inclination, i.e., in a helical or screw-line configuration, in order to thereby augment the movement of the fiber stock mass in a desired direction, for instance towards the outlet for the stock which is to be separated out of the housing 1. 
     As will be particularly apparent by inspecting FIG. 3, the housing 1 is equipped with infeed lines or conduits 14 and 15 for the infeed of water. Nozzles 14&#39; and 15&#39;, defining discharge openings, extend from such water infeed lines 14 and 15, respectively, into the internal space of the housing 1. At the ejection or output side of the rotor 6, which is governed by its direction of rotation as represented for instance by the not particularly referenced arrow of FIG. 3, there is located within the housing 1 at the vertical wall 5 a series of adjustable guide ribs or ledge members 16. In the illustration of FIG. 1 these guide ribs or ledge members 16 can be inclined with respect to the axial direction of the rotor 6. Such guide ribs or ledge members 16 influence the movement of the fiber stock mass in the axial direction of the rotor 6. 
     As shown in FIGS. 1 and 3, an infeed conduit or pipe 17 is provided for the infeed of the fiber stock mass which is to be sorted or classified. This infeed conduit 17 piercingly extends through the deflection or guide surface 12. At the left-hand end of the illustration of FIG. 1 the sorting apparatus is provided with an outlet shaft or chute 18 or equivalent structure for the overflow stock which has not passed through the screen or sieve 3. Between the screen 3 and the outlet or discharge shaft 18 there is located an overflow section or edge 20. 
     Arranged beneath the housing 1 is a collecting or catch container 21 for the throughput stock which has passed through the screen or sieve 3. Both the collecting or catch container 21 and also the housing 1 are secured to a suitable support structure or framework 22 which simultaneously carries bearing blocks 23 for the rotor shaft 7. This rotor shaft 7 is operatively connected by means of a coupling 24 with a suitable drive motor 25. As also will be recognized from FIG. 1, the rotor 6 is equipped with substantially disk-shaped separation or partition walls 26 which are arranged essentially perpendicular to the lengthwise axis A of the rotor 6. These partition or separation walls 26 mutually separate from one another individual sections of the blades or vanes 8 and 10. Between the separation walls 26 the blades or vanes 8 and 10 are offset with respect to one another, as such will be apparent from the showing of FIG. 3. Consequently, there can be equalized the rotational moment or torque during driving of the rotatable rotor 6. 
     During operation of the equipment the rotor 6 is rotated by the action of the drive motor 25 at a relatively high rotational speed suitable for propelling the fiber stock mass. In the event that a partially pulped mass of waste paper is to be processed, then such is introduced, for instance from a conventional stock slusher or pulper, through the infeed line or conduit 17 into the housing 1. Due to the rotation of the rotor 6 this mass, which already contains de-fiberized paper fibers and also surface-like or substantially flat parts, such as lumps of paper, foil pieces and so forth as well as a proportion of water, is initially propelled against the screen or sieve 3, so that part of the fibers can pass through the screen 3 into the catch or collecting container 21. The part of the stock which has not passed through the screen 3 is acted upon by the clearing blades or vanes 8, elevationally propelled upwardly and slides along the deflection or guide surface 12 back again into the effective region of the rotor 6, whereupon this process repeats. 
     In this manner there is accomplished an extremely intensive agitation or placement of the mass into a state of turbulence, and such intensively agitated mass moves under the action of the adjustable guide ribs or ledges 16 towards the outlet or discharge shaft or chute 18. During such agitation and movement there are eliminated, on the one hand, free paper fibers through the screen or sieve 3 and not yet de-fiberized paper pieces are further de-fiberized. On the other hand, foil pieces or the like remain upon the screen 3 and are practically not further comminuted by the turbulent action. They finally arrive in the form of overflow stock at the outlet or discharge shaft 18. 
     In similar fashion it is possible to also process in such equipment cellulose or wood pulp for the fabrication of paper. In such case there is introduced into the housing or container 1 the fiber stock suspension which has been formed in the stock slusher or pulper. It is possible to eliminate contaminants, such as for instance wood fragments or shives as the overflow through the outlet shaft or chute 18. The fibers forming the throughput stock once again arrive at the collecting container or receptacle 21. However, the cellulose or wood pulp can also be fractionated or classified with the inventive equipment if the size of the holes or openings 3a of the screen 3 are appropriately selected. In this way shorter fibers can move in the form of throughput stock through the screen or sieve 3 into the collecting container 21, whereas the longer fibers can form the overflow stock and can move into the outlet shaft 18. 
     FIGS. 4 and 5 depict further possible exemplary embodiments of the deflection or guide surface 12. In the arrangement of FIG. 4 the deflection or guide surface 12 is structured to be appreciably shorter than the deflection or guide surface 12 of the arrangement of FIGS. 2 and 3. In this case there can be dispensed with the guide ribs or ledge members 13. 
     According to the modified version of FIG. 5, the deflection or guide surface 12 is formed by an arcuate-shaped insert 12&#39; as well as by a flat or planar cover member 12&#34;. Under certain circumstances it is even possible to dispense with the use of the insert or insert member 12&#39;. 
     Based upon the showing of FIG. 5 there will also be explained in greater detail the mode of operation of the sorting appartus. 
     The fiber stock mass is introduced into the housing or container 1 in the direction of the solid line or broken line depicted arrows P and arrives at the axial region of the rotor 6. Thereafter, the thus introduced fiber stock mass is acted upon by the blades or vanes 8 or 10 and propelled against the screen or sieve 3. Due to the infeed of the fiber stock mass to the axial region of the rotor 6 there is realized the possibility that the inputted mass can arrive between the blades or vanes 8 or 10, so that such fiber stock mass can be propelled by the shorter blades or vanes 10, serving for propelling of the mass, in the direction of the arrow R at a relatively steep angle α against the screen or sieve 3. As a result, there is thus augmented, on the one hand, the de-fiberizing of not yet completely de-fiberized paper fibers, and, on the other hand, there is also enhanced the penetration of the already de-fiberized paper fibers into and through the holes or openings 3a of the screen 3. The longer blades or vanes 8, while also participating in such propelling action, however perform their primary function of clearing or cleaning the screen or sieve 3, as such has been generally indicated by the paper mass O which has been displaced or pushed by the lower blade or vane 8 of the showing of FIG. 5. 
     With the embodiment of equipment as depicted in FIG. 6, which in all other respects essentially corresponds to the arrangement of FIGS. 1 to 3, the infeed conduit or pipe 17 is replaced by an infeed vat or trough 30. This infeed vat or trough 30 has an overflow section or edge 31 i.e. a weir, by means of which the processed mass drops into the housing 1. 
     As also will be evident from the illustration of FIG. 6, the infeed vat or trough 30 extends over a length M of the part of the housing 1 provided with the screen or sieve 3, and which length M of the infeed vat 30 is greater than one-half of the length of the housing 1. The remaining section N is provided with infeed lines or conduits 14 for water. With this arrangement the screening operation is accomplished in the section M only under the influence of the water contained in the inputted mass. When water is freshly infed from the lines or conduits 14 there is only flushed the overflow stock which then arrives at the outlet shaft or chute 18. It should be understood, however, that when inputting material having a higher stock density it would be possible to also arrange infeed lines for water at the section M of the equipment. 
     FIG. 8 depicts an exemplary embodiment of sorting apparatus containing a housing or container 1 which is essentially symmetrically constructed and centrally possesses an output shaft or chute 18. In corresponding manner there are provided two collecting or catch containers 21. 
     FIGS. 9 and 10 depict two possible exemplary embodiments of the sorting apparatus containing two rotors with essentially parallel axes. It is to be understood that in such FIGS. 9 and 10, and equally in the other FIGS. of the accompanying drawings, there have been generally used throughout the drawings the same reference characters to denote the same or analogous components. 
     With the embodiment of FIG. 9 a second rotor 40 is located within the housing 1 above the rotor 6. This second rotor 40 can be constructed similar to the rotor 6. This second rotor 40 serves for propelling back the fiber stock mass to the rotor 6 which initially was upwardly propelled by such rotor 6. 
     A similar action is achieved with the exemplary embodiment of sorting apparatus depicted in FIG. 10, wherein, however, two similar or identical rotors 6 are provided at the same elevational position, each of these rotors 6 cooperating with a respective screen or sieve 3. 
     Finally, FIG. 11 shows a possible arrangement of the blades or vanes 8 or 10 upon the rotor shaft 7 of the rotor 6. In this case the blades 8 or 10 are arranged at an angle with respect to the lengthwise axis A of the shaft 7. In this way there is augmented the transportation or conveying of the treated fiber stock mass in the axial direction of the housing 1 towards the outlet shaft or chute 18, so that it is possible, under circumstances, to dispense with the use of the adjustable guide ribs or ledge members 16. On the other hand, the blades or vanes 8 or 10 and the guide ribs or ledge members 16 can be structured and arranged to operate in opposing relationship with respect to one another, so that there can be retarded the axial movement of the mass within the equipment or there can be achieved an internal circulation movement. 
     Turning again at this point to FIG. 5 it will be recognized that there has been illustrated therein a further possibility for the infeed of water into the housing or container 1. Thus, the hollow space or region 7&#39; of the shaft 7 of the rotor 6 can be connected with a not particularly illustrated water line or conduit which has merely been symbolically represented by reference character 50. The shaft 7 is then provided with discharge openings or bores 7&#34; which permit the efflux of the water towards the outside. 
     It should be understood that the screen or sieve 3 or equivalent structure need not possess the shape of a semi-cylindrical surface, as such has been illustrated in several of the accompanying FIGS. of the drawings. As depicted in FIG. 5, it is possible for such screen 3 to also have a planar or flat section or portion 3&#39; which merges with the cylindrical surface. On the other hand, the cylindrical surface formed by the screen 3 can be smaller than a semi-cylinder, as the same has been depicted, for instance, in FIG. 10. Finally, it is to be understood that the screen or sieve 3 need not be cylindrical in its shape, rather generally can possess the form of a body of revolution. Thus, for instance, it can be conical or can be composed of a number of cylindrical sections of different diameter. 
     It is possible to input to the sorting apparatus, separately from the water, fiber stock masses possessing a higher stock density. In such case, with the embodiments depicted in FIGS. 6 to 8 the vat or trough 30 can serve for the infeed of the water, whereas the fiber stock mass can be inputted separately, for instance through pipes comparable to the pipes or conduits 17. 
     While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practiced within the scope of the following claims. Accordingly,