Abstract:
A device for processing feed material, with a housing enclosing a processing space in which a rotor rotatable about the axis of rotation is arranged. The rotor has a rotor disk at which circumference a plurality of axially disposed impact plates is arranged uniformly distributed. A coaxially arranged processing path surrounds the impact plates while maintaining a working gap. Via a material inlet, the device is fed in the axial direction with feed material centrally ending in the processing space, which upon deflection in the region of the rotor disk is fed in the radial direction to the working gap. To ensure complete and gentle processing of the feed material while maintaining its original taste, smell and color, the processing path is part of a basket rotating about the rotational axis.

Description:
[0001]    This nonprovisional application claims priority under 35 U.S.C. § 119(a) to German Patent Application No. 10 2015 117 430.8, which was filed in Germany on Oct. 13, 2015, and which is herein incorporated by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates to a device for the comminution of feed material with a housing enclosing a processing space, in which a rotor rotatable about a rotational axis is arranged, wherein the rotor has a rotor disk at which circumference a plurality of axially aligned impact plates are arranged uniformly distributed, which are surrounded by a coaxially arranged processing space while maintaining a working gap, wherein the device is fed material in an axial direction by means of a material inlet centrally opening into the processing space, and the feed material, after deflection in the area of the rotor disk, is fed in the radial direction to the working gap. 
         [0004]    Description of the Background Art 
         [0005]    During processing of organic substances such as foodstuffs and feed material, spices or lignocellulosic materials and the like, operators of corresponding installations are confronted with different challenges, depending on the type of feed material and the desired end product, wherein in a variety of cases, the main consideration is the pure comminution of the feed material to a predetermined size and shape. 
         [0006]    However, the processing of foodstuffs and feed material also requires a gentle way of material processing, as the gustatory and olfactory properties as well as the original color of the final product should be maintained. This applies in particular to the processing of spices, which occur mostly in the form of nuts, grains, leaves and roots, and which generally have volatile aromatic substances, such as, for example, essential oils. Too much heat input during feed material processing results in a loss of the volatile substances, which represents a considerable loss in quality. Foodstuffs and feed material also have a tendency of adhering to machine parts due to their relatively high moisture content as well as their fat and oil-containing ingredients. There is therefore a risk of material accumulation during processing, which hinders an undisturbed flow of material through the processing machine and therefore requires regular cleaning, in turn increasing the proportion of machine downtimes. 
         [0007]    When preparing lignocellulosic materials such as bagasse or bark, on the other hand, the challenge may be to extract substances from the feed material, for example, fiber-containing ingredients, which are needed as raw material for further production processes such as the production of panel materials, or as starting materials for extracting plant extracts. 
         [0008]    Both the specific properties of the raw materials and of the final products determine the technical features of the machines used. To this end, the use of universal mills, pin mills, hammer mills, impact mills and the like is known for the processing of organic substances. These mills are characterized by a high comminution capacity, but simultaneously cause a relatively high heat input into the product, which particularly in the treatment of foodstuffs and spices leads to a loss in taste-determining substances. To achieve comminution at low temperatures, it is already known in this regard to add a coolant such as CO 2  during processing. 
       SUMMARY OF THE INVENTION 
       [0009]    It is therefore an object of the invention to provide complete and gentle processing of organic substances while preserving their original taste, smell and color. 
         [0010]    This object is achieved in an exemplary embodiment by a device in which the processing path is part of a basket rotating about the axis of rotation, wherein the processing path is divided in the axial direction into a first track section and at least one further, second track section adjoining axially thereon, and wherein the face of the rotor disk facing the feed opening ends with its outer peripheral area in the separating plane between the first path section and the second path section or in the region of the first track section. 
         [0011]    A substantial advantage of the invention compared to known devices results from the combination of a rotor disk whose relative position within the basket according to the invention allows for the entire feed flow to be successively processed first in the area of the first processing path, and then in the area of the second processing path, with a continuously variable differential speed between the rotor and the basket, which allows for an individual adaptation of the processing to the nature and sensitivity of the feed material. The interaction of these two features ensures that the entire feedstock is completely processed, taking into account the characteristic properties of the feedstock. For example, at a low differential speed, heat-sensitive or brittle materials such as foodstuffs and spices can be crushed extremely gently, while when selecting a higher differential speed, hard feed material such as grain is subjected to more intensive processing. The result is a homogeneous end product in shape and size as well as material and taste, which also meets the highest quality requirements. 
         [0012]    In an embodiment of the invention, the first processing path and the second processing path embody different processing modes, for example, in that the first processing path has a baffle web and the subsequent second processing path has a screen web. In the course of the successive cycle of the two processing paths, the feed material is gradually processed within the device, wherein each stage can be adapted to the respective requirements of the material processing, or wherein it is the interaction of the two stages that leads to a desired overall result. 
         [0013]    In this sense, it is also possible to modify the inner circumference of the individual processing paths that is active during machining by integrating individual circumferential sections. Thus, circumferential sections with other shaping or with screens can be used as a first processing path in a baffle web, and/or circumferential sections without perforation or with comminuting effect can be used in a screen web as a second processing path. In this way, a finely graduated adaptation of an inventive device to the respective feed material is provided. Preferably, the successive circumferential sections are flush with one another in the circumferential direction, which promotes a uniform material flow through the device. 
         [0014]    Furthermore, it can prove to be advantageous for certain types of processing if the surfaces of the first track section and the second track section, which are active during processing, merge in an axially aligned manner. The radial width of the working gap present in the area of the first track section is maintained in this embodiment in the region of the second track section, which promotes radial material passage in the area of the second track section. 
         [0015]    A further optional possibility for modifying the material processing is an embodiment of the invention in which the impact plates are divided into two impact plate parts, wherein the first impact plate part is assigned to the first processing path and the second impact plate part is assigned to the second processing path. This, on the one hand, permits the use of differently designed impact plate parts in the different processing stages; on the other hand, the radial gap between the active impact plate edge and the associated track section in the different track sections can be chosen to be of a different size, in order to, for example, control the residence time of the feed material in the respective track section. 
         [0016]    The axially parallel impact plates enclosing the basket in the shape of a collar have their ends extending into the region of the carrier disk or the ring carrier disk. In order to achieve the most efficient processing of the feed material, preferably, the axial gap between one end of an impact plate and the adjacent disk is a maximum of 50 mm, most preferably a maximum of 20 mm. 
         [0017]    To minimize maintenance and repair-related downtime, the areas of the carrier disk and the ring carrier disk axially opposing the impact plates are designed to be wear-resistant. For this purpose, for example, a ring or a plurality of ring segments made of a wear-resistant material may be arranged, or the window surface is tempered in this area. 
         [0018]    An embodiment of the invention is characterized by means which supply a process gas to the material flow in the processing zone. In the simplest case, the process gas is a cooling medium which counteracts excessive heating of the feedstock in the course of the material processing. However, it is also possible to supply conditioned gas to the machining process, in order to, for example, dry or moisten the feed material, or to regulate the moisture content in the final product. 
         [0019]    In addition, it is possible to feed substances to the feedstock with the process gas, which provide the end product with advantageous properties. For example, taste or odor alteration or flavor enhancers, or substances for color change or color intensification of the final product may be added. A further possibility is to add substances to the feedstock to improve the shelf life of the final product, for example, preservatives or substances to maintain a certain consistency of the final product, for example, to prevent clumping and caking of the material particles. 
         [0020]    Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes, combinations, and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein: 
           [0022]      FIG. 1  is a longitudinal section through a first embodiment of a device according to the invention, along the line I-I shown in  FIG. 2 , 
           [0023]      FIG. 2  is a cross-sectional view through the device shown in  FIG. 1 , along the line II-II shown there, 
           [0024]      FIG. 3  is a longitudinal section through a second embodiment of the device according to the invention, in the region of the working gap, 
           [0025]      FIG. 4  is a cross-section through a third embodiment of a device according to the invention, in the region of the second track section with a view to the housing rear wall, and 
           [0026]      FIG. 5  is a longitudinal section through a fourth embodiment of the device according to the invention, in the region of the working gap. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]      FIGS. 1 and 2  show a first embodiment of the inventive device  1  in the form of an impact mill. The device  1  has one cylindrical housing  3  enclosing a rotational axis  2 , with a housing front wall  4 , a housing rear wall  5  and a housing shell  6  connecting the front wall  4  and the rear wall  5 . 
         [0028]    The housing front wall  4  has an opening  7  concentric with the axis of rotation  2 , which can be closed by means of a pivotable housing door  8 . Concentric to the rotational axis  2 , the housing door  8  has a feed opening  9 , at which edge facing the housing interior, a circumferential projection  10  is arranged. On the opposite, outer side of the housing door  8 , a tubular material inlet  11  connects to the opening  7 , by means of which an axial feed of the device  1  with feed material  12  takes place. To discharge the sufficiently processed material, the housing  3  opens downwards and thus forms a material outlet  20 . 
         [0029]    On the rear wall  5  of the housing  3 , in the region around the axis of rotation  2 , a shaft bearing  13  is attached, in which a first drive shaft  14  is rotatably mounted in the form of a hollow shaft for rotatably receiving a second drive shaft  15 . Both first and second drive shafts  14 ,  15  each have on their ends situated outside the housing  3  a multi-groove disk (not shown), which is driven in the same or opposite direction at a differential speed. 
         [0030]    With its end located inside the housing  3 , the first drive shaft  14  bears a basket  16  which coaxially surrounds the axis of rotation  2 . The basket  16  is essentially composed of a support disk  17  perpendicular to the axis which is coaxially opposed by a support ring disk  18  at an axial distance. The insides of the support disk  17  and the support ring disk  18  are connected via an equally coaxially aligned, cylindrical processing path  19 . The basket  16  is seated with the support disk  17  on the first drive shaft  14 , while the support ring disk  18  abuts the outer circumference of the extension  10  of the housing door  8  with its inner circumference in a sliding manner. In order to prevent a passage of material there, which would result in unprocessed feed material directly entering the material outlet  20 , the connection of the support ring disk  18  is formed as a sealing gap  44  on the projection  10  of the housing door  8 . 
         [0031]    In the present exemplary embodiment, starting at the support ring disk  18  in the axial direction, the processing path  19  is subdivided into a first cylindrical track section  21  and an adjoining, second cylindrical track section  22 . The first track section  21  is formed by a baffle web with fluted portions in order to comminute and pulp the feed material. It is possible to modify the baffle web by section, for example, with different shaping or through the integration of individual screening surfaces. The subsequent second track section  22  has a screen web which allows for radial passage of the feed material after comminution thereof under the hole diameter. With a suitable screen design or by sectional integration of impact segments or segments without perforation into the screen, a part of the comminution work can also take place in the region of the second track section  22 . 
         [0032]    Finally, in the outer peripheral region of the basket  16 , there are three winged or scoop-like strippers  23 , which are uniformly and mutually spaced apart between support disk  17  and support ring disk  18 , radially outwards into the region of the housing shell  6  and, in the course of their rotation, keep the channel  24  formed between housing shell  6  and basket  16  free from deposits. To support the airflow through the device  1 , the support disk  17  and support ring disk  18  also comprise fan blades  31  that radially extend outwardly on the outer sides facing the housing  3 . 
         [0033]    Within the basket  16 , a rotor  25 , which also rotates about the axis  2 , is arranged. The rotor  25  comprises a hub body  26  with which is non-rotatably mounted on the end of the second drive shaft  15  situated inside the housing  3 . The hub body  26  monolithically reaches radially outwards to a rotor disk  27 , the thickness of which increases in the region of the outer circumference and which outer circumference has a number of uniformly spaced brackets  28  in the circumferential direction which are designed to fasten axially parallel impact plates  29 . The radially outer effective edges of the impact plates  29  lie on a common circle track and form a working gap with the processing path  19 . 
         [0034]    The rotor disk  27  thereby divides the space enclosed by the basket  16  into a first chamber  45 , delimited by the support ring disk  18  and the rotor disk  27 , and a second chamber  46 , delimited by the support disk  17  and the rotor disk  27 . 
         [0035]    The relative axial position of the rotor disk  27  to the processing path  19  is such that the face  30  of the rotor disk  27  which faces the feed opening  9 , is disposed in the region of the first track section  21  or in the separating plane between the first track section  21  and the second track section  22 . In this way, the feed material  12  is fed completely to the first track section  21  in the region of the first chamber  45 , before it reaches the region of the second track section  22 . 
         [0036]    During operation of a device  1  according to the invention, the basket  16  is driven at a differential speed over the first drive shaft  14 , and the rotor  25  via the second drive shaft  15 . With synchronous driving at only a small rotational speed difference, a particularly gentle processing mode can be realized. With an increase in speed differences up to an opposing movement of basket  16  and rotor  25 , on the other hand, the proportion of the quantity of comminuting energy introduced into the feed material can be infinitely increased and thus, the crushing performance improved. 
         [0037]    The feed material  12  first passes via the feed line  11  and through the feed opening  9  in the axial direction into the central region of the rotor  25 , where it is deflected outward in a radial direction at the face  30  of the rotor disk  27 . As a result of the relative position of the face  30  of the rotor disk  25  to the processing path  19 , the material flow is first completely fed to the first track section  21 , and there, crushed and pulped sufficiently, before the feed material reaches the axially adjoining region of the second processing path  22  in the form of a screen web. After radial passage of the sufficiently processed material through the second track section  22 , it is fed into the material outlet  20  in the channel  24 . 
         [0038]      FIG. 3  shows a further development of the device  1  shown in  FIGS. 1 and 2 , so that as long as the same conditions apply, the foregoing applies accordingly and identical reference numbers are used. The various modifications realized on the device  1  can be the subject of further embodiments of the invention, individually and independently of one another, or as can be seen in  FIG. 3 , can exist cumulatively in a single embodiment. 
         [0039]    A first modification relates to the supply of a process gas to the region of the processing zone. The process gas can have a pure cooling function and/or a drying function, to which end ambient air or conditioned gas is fed into the housing  3 . However, it is also possible to add substances to the material flow, which alter its properties. These substances can be, for example, flavorings which influence the flavor of the final product, and/or substances which contribute to the shelf life of the end product, and/or substances which give the product a certain color or preserve its color. 
         [0040]    As can be seen from  FIG. 3 , the process gas  32  is fed from the rear side of the device  1 . For this purpose, a cavity  33  is formed at the rear side of the housing  5  in the region below the shaft bearing  13 , said cavity being charged with process gas  32  via an opening  34 . Via a further opening  35 , the process gas  32  discharges from the cavity  33  into an annular space  36  coaxially enclosing the first drive shaft  14 . The outer boundary of the annular space  36  is formed by a projection  37  at the housing rear  5  centrically circulating the axis  2 . Via axial through-bores  38 , the process gas  32  enters the interior of the housing  3 , where it is distributed in a further annular space  39 , before finally passing through bores  40  in the support disk  17  into the second chamber  46  between the rotor disk  27  and the support disk  17 , where it is guided radially into the region of the second track section  22 , where it is mixed with the material flow. 
         [0041]    Another modification relates to the formation of the impact plates  29 , which in the embodiment shown in  FIG. 3  are divided in the axial direction, into a first impact plate part  29 ′ which interacts with the first track section  21 , and a second impact plate part  29 ″ which interacts with the second track section  22 . The first impact plate part  29 ′ and/or the second impact plate part  29 ″ are fixed in the respective holders  28  in a radially adjustable manner, so that the radial width of the working gap in the region of the first track section  21  and/or the second track section  22  is individually adjustable, whereby, for example, the length of stay of the feed material in the track sections  21 ,  22  can be adjusted individually. 
         [0042]    Furthermore,  FIG. 3  shows a further modification in which the regions axially opposing the ends of the impact plates  29 ,  29 ′,  29 ″ located on the inner sides of support disk  17  and support ring disk  18  have wear protection. In the present exemplary embodiment, the wear protection includes, in each case, a ring  41  or of ring segments which are joined to form a ring  41 , which are bolted to the support disk  17  or the support ring disk  18 . 
         [0043]    The embodiment of the invention illustrated in  FIG. 4  is in turn based on the embodiment shown in  FIGS. 1 and 2  or  FIG. 3 , so that, in order to avoid reiterations, reference is made to the latter embodiments. In contrast to the embodiments described above, the second track section  22  has gaps in the circumferential direction, where circumferential sections  42  are interspersed in the second track section  22 . The second track section  22  and the interspersed circumferential sections  42  are flush with each other in the circumferential direction. The circumferential sections  42  can be, for example, without perforation and, if appropriate, have a profiled surface at their inner circumference. If the circumferential sections  22  are made of baffle web sections, as shown in  FIG. 4 , then these are supported in the radial direction by beams  43  axially extending between the support disk  17  and the support ring disk  18 . 
         [0044]    Analogously to this embodiment, the first track section  21  can also have gaps in the profiling in the circumferential direction, where the first track section  21  is replaced by different circumferential sections. These circumferential sections can differ from another, for example, by a different profile or by means of a sieve-like configuration. 
         [0045]    The subject of  FIG. 5  is a further embodiment of the invention, which is substantially the same as the ones described above, but is characterized by an arrangement of the first track section  21  and the second track section  22 , in which the inner circumference of the first track section  21  is at the same radial distance from the axis of rotation  2  as the inner circumference of the second track section  22 . 
         [0046]    For this purpose, the processing path  19  comprises a base ring  47  assigned to the first track section  21  and a bearing ring  48  assigned to the second track section  22 . The base ring  47  is centered coaxially with the axis  2  via a form-fit at the inner side of the support ring disk  18 . The same applies to the bearing ring  48 , which engages positively on the inner side of the support ring  17  and is also coaxially aligned with the axis  2 . By means of a plurality of clamping bolts  49  which are distributed over the circumference and which in each case permeate the support ring disk  18  and engage in the support ring  17  with their threaded portion, the base ring  47  and bearing ring  48  are fixed in their position, whereby in each case a spacer sleeve  50  slipped onto the clamping bolt  49  provides the appropriate axial distance between base ring  47  and bearing ring  48 . 
         [0047]    In the transition region to the second track section  22 , the base ring  47  has a circumferential ring shoulder  52  extending over the inner shell surface in the direction of the axis  2 , which serves as a first bearing surface for the edge of a second track section  22 . The opposing edge of the perforated screen  53  is supported by a second bearing surface, which is formed by a circumferential recess  54  in the bearing ring  48 . By means of optional adjustment devices such as distance plates, lining pieces or adjusting screws which are arranged between the bearing surfaces and the perforated sieve  53 , the relative position of the second track section  22  can be adjusted.  FIG. 5  clearly shows that the clear radial distance of the first track section  21  to the axis  2  corresponds to the clear radial distance of the second track section  22  to the axis  2 . The inner shell surface of the first track section  21  and the second track section  22  are thus aligned in the axial direction. 
         [0048]    The remaining components, such as housing  3 , rotor  25 , impact plates  29 , rings  41 , etc., correspond to the above-described embodiments, so that what was said there applies accordingly. Thus, it is also apparent from  FIG. 5  that the face  30  of the rotor disk  27  is disposed in the region of the first track section  21  at least with its outer peripheral region. 
         [0049]    The invention is not limited to the feature combinations disclosed in the individual embodiments. Rather, combinations of features of different embodiments self-explanatory to those skilled in the art are also possible within the scope of the invention. 
         [0050]    The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.