Abstract:
A tearing mill for comminuting fruits is equipped with a rotatably supported plate having tearing elements And with a stuffing device with a feed screw for delivering the fruits to the plate. A gap of adjustable width exists between the stuffing device and the plate. By means of an independent control of the gap and the rotational speed of the feed screw and plate, a mash structure of the comminuted fruits is achieved which is well adapted to the type of fruits and to subsequent processing of the mash.

Description:
[0001]    This is a continuation of application Ser. No. 09/647,714 filed on Oct. 4, 2000, the entire content of which is incorporated herein, which was a U.S. national stage application filed under 35 U.S.C. §371 based on International Application No. PCT/CH00/00029 filed on Jan. 21, 2000, which international application was not published in English by the International Bureau. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention relates to an apparatus for comminuting organic substances, in particular for tearing apart fruits, including a plate supported rotatably about its axis along with a motor for driving it to rotate, with tearing elements disposed on one face end of the plate, and including means for delivering the organic substances to the face end of the plate.  
         BACKGROUND OF THE INVENTION  
         [0003]    A drum-type cutting machine, particularly for cutting sugar beets into pieces, is known from U.S. Pat. No. 4,584,919 (Bittner). It has a number of retaining elements that are disposed at equal spacings over the circumference of the drum and extend substantially parallel to the axis of the drum. A knife chest in which at least one cutting knife whose cutting edge extends substantially circumferentially is secured is retained between each two retaining elements.  
           [0004]    Various embodiments of drum mills of this type are also known for tearing apart fruits, such as the types sold under the name Central by Bucher-Guyer AG, Niederweningen, Switzerland. A drum mill of this kind includes a drum body, made in one piece, over whose circumference retaining elements for the tearing knives are disposed at small spacings. In the operationally ready state, the drum of such a mill forms a substantially closed hollow chamber with a unilateral axial opening through which the fruits to be torn apart are delivered by means of a transporting screw.  
           [0005]    In such drum mills, the following disadvantages have been demonstrated:  
           [0006]    The fruits, especially apples, revolving at high speed in the drum create major imbalancing forces. The entire mill shakes and causes a great deal of noise. The imbalancing forces also adversely affect the service life of the bearings used for the drum.  
           [0007]    Despite variation in terms of tooth pitch of the knives, the structure of the resultant mash can be varied only little. However, this structure influences the mash yield/performance in subsequent pressing operations, and this cannot be improved by optimizing the process.  
           [0008]    Foreign bodies in the fruit product, such as stones, cause relatively major imbalance and cause severe damage to the tearing knives.  
           [0009]    A fruit stuffing aid and the grinding drum operate at the same rotary speed. The mill fails to function at maximum capacity, since practically no prestuffing takes place. If too little fruit is delivered, the proportion of fine particles in the mash will be very high. This adversely affects the performance of an ensuing pressing operation and leads to clogging of filters for separating solids and liquids.  
           [0010]    The casing of the grinding drum with the requisite mash outlet slots is very complicated to manufacture.  
           [0011]    A plate-type cutting machine, particularly for cutting sugar beets into pieces, is also known from U.S. Pat. No. 4,683,790 (Bittner). This machine includes a machine stand and a plate cutter with a bearing and a drive mechanism. The plate cutter has a flat top and uniformly distributed openings for the cut-up product, which preferably extend a long way radially. Receptacles for cutting knives are disposed at the openings.  
           [0012]    In plate-type cutting machines of the known type, the plate cutter usually comprises a steel plate with rectangular openings for the cut-up product. In such plate mills, the following disadvantages have been demonstrated:  
           [0013]    Low capacity, since only part of the plate is acted upon.  
           [0014]    A stuffing screw for delivering the product is either missing entirely or runs at the same rotary speed as the plate, leaving to an inadequate stuffing effect.  
           [0015]    Excessively large thread pitches of the stuffing screw cause overload or blockage.  
           [0016]    The function of the plate mill is only poorly adapted to the type of product to be ground.  
           [0017]    The product of a cutting machine is unsuitable as pressing product for juice extraction.  
         SUMMARY OF THE INVENTION  
         [0018]    The object of the invention is to overcome the disadvantages of the known apparatuses for comminuting organic substances through a novel design.  
           [0019]    According to the invention, this object is attained in an apparatus of the type defined at the outset in that the means for delivering the organic substances are embodied as a stuffing device with a drive motor, and that the stuffing capacity of the stuffing device and the comminution capacity of the rotatably supported plate are adjustable independently of one another.  
           [0020]    The stuffing device preferably includes a feed screw whose axis is located substantially in an extension of the plate axis. Advantageously, the stuffing device delivers the organic substances substantially to the entire end face of the plate via a cylindrical housing, whose outlet is opposite the end face at a spacing distance, and the cylindrical housing includes guide elements which block a rotary motion of the delivered organic substances. The tearing elements, disposed on the face end of the plate, are embodied as a plurality of interchangeably secured, substantially radially- extending tearing strips with sawlike edges, and on the face end of the plate, directly next to the radially-extending tearing strips, at least on one side thereof, there is a groove with an open end on the outer edge of the plate for carrying the comminuted organic substances away.  
           [0021]    Advantageous operation of the apparatus is made possible by sensor means for detecting the operative torque in the rotational drive of the rotatably supported plate, as well as control means, operatively connected to the sensor means, for adjusting the stuffing capacity of the stuffing device to a value that corresponds to a predetermined value of this torque.  
           [0022]    Further variants of the apparatus are defined by the claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       [0023]    Exemplary embodiments of the invention are described in further detail in the ensuing description and in the drawing figures.  
         [0024]    [0024]FIG. 1, a schematic cross section through a tearing mill for fruits having a comminution apparatus according to the invention.  
         [0025]    [0025]FIG. 2, a cross section through a unilateral groove of rectangular profile next to a tearing element in a turning plate of the tearing mill of FIG. 1.  
         [0026]    [0026]FIG. 3, a cross section through a groove on both sides of a tearing element in a turning plate of the tearing mill of FIG. 1.  
         [0027]    [0027]FIG. 4, a cross section through a unilateral groove of round profile next to a tearing element in a turning plate of the tearing mill of FIG. 1.  
         [0028]    [0028]FIG. 5, a cross section through a unilateral groove of beveled profile next to a tearing element in a turning plate of the tearing mill of FIG. 1.  
         [0029]    [0029]FIG. 6, a cross section through a casing of a cylindrical housing of a stuffing device for delivering product to the tearing mill of FIG. 1.  
         [0030]    [0030]FIG. 7, a plan view on a turning plate of the tearing mill of FIG. 1.  
         [0031]    [0031]FIGS. 8 a ,  8   b ,  8   c , two radial longitudinal sections and one radial cross section through a bearing of a turning plate of the tearing mill of FIG. 1 by means of spacer bolts, in various axial positions.  
         [0032]    [0032]FIG. 9, a detail of an interchangeable wear ring on the cylindrical housing of the stuffing device for delivering product in accordance with FIG. 1, in a cross section perpendicular to the housing axis.  
         [0033]    [0033]FIG. 10, the detail of FIG. 9, in a cross section parallel to the housing axis.  
         [0034]    [0034]FIG. 11, a radial section through a detail with an axially adjustable wear ring on the cylindrical housing of the stuffing device for product delivery of FIG. 1, for varying a grinding gap between the wear ring and a turning plate of the tearing mill of FIG. 1.  
         [0035]    [0035]FIG. 12, a radial plan view on the detail of FIG. 11.  
         [0036]    [0036]FIG. 13, a diagram of a regulating device with control elements for the tearing mill of FIG. 1, for selecting the structure of the comminuted ground product.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0037]    As the schematic cross section through a tearing mill for fruits with a comminution apparatus according to the invention shows in FIG. 1, this tearing mill includes a plate  2 , supported rotatably about a horizontal axis  1 , along with a motor  3  for driving it. On one face end of the plate  2 , as shown more precisely in FIG. 7, a plurality of tearing strips  4  are disposed radially. An axis  5  of a feed screw  6  of a stuffing device  7  for delivering organic substances for comminution is disposed in an extension of the axis  1 . The feed screw  6  is located in a cylindrical housing  8  with an inlet opening  9  and an outlet  10  located opposite the face end of the plate  2 . For driving the feed screw  6 , a motor  11  is disposed on the housing  8 .  
         [0038]    The plate  2  and the feed screw  6  advantageously rotate in opposite directions. The rotary speed of the plate  2  is substantially greater than that of the feed screw  6 . The plate  2  along with its motor  3  are mounted on a flange plate  12  which is releasably joined to the housing  8 . The group of components comprising the motor  3 , flange plate  12  and plate  2  is pivotable away from the housing  8  and into a vertical position of the axis  1  by means of a pivoting device  13 . This makes the face end of the plate  2  having the tearing strips  4  readily accessible for purposes of cleaning and tool changing. As FIG. 1 shows, the housing  8  extends beyond the outlet  10  and surrounds the plate  2  with a unilaterally open annular channel  14 , which is adjoined at the bottom by a discharge chute  15  for the comminuted organic substances.  
         [0039]    For better diversion of the comminuted organic substances separated from the plate  2 , the housing  8  forms an acute angle with the plane of the plate, at least in the region of the plate  2 . As can be seen in FIG. 1 and in more detail in FIG. 6, four strips  16  are disposed axially parallel on the inside of the casing of the cylindrical housing  8  and act as a rotation block for the organic substances drawn in by the feed screw  6 .  
         [0040]    These rotation blocks prevent or reduce the product being ground from rotating along with the feed screw  6 . The goal is for the fruits, such as apples, to reach the plate  2  in the form of blocks. An overly great relative motion of the apples to one another increases the proportion of fine particles in the ground product. The comminuted mash is spun from the plate  2  into the annular channel  14  of the housing  8 . The structure of the mash should be destroyed as little as possible in this operation. Because of the inclined position of the housing  8  in the region of the plate  2 , an impact angle of the mash of between 15° and 75° is advantageously attained. The mash then drops to the outside via the discharge chute  15 .  
         [0041]    In addition to the strips  16 , a further rotational block  17  with a support plate  18  can be seen at the outlet  10  of the housing  8  in both FIGS. 1 and 6. To improve the tearing action, the tearing strips  4  have sawlike edges, which are engaged by the rotational block  17  during operation of the tearing mill to remove fibers from the teeth using a counterpart set of teeth. The plate  2  is located opposite the outlet  10  of the housing  8 , at a spacing distance across a grinding gap  19 . The grinding gap  19 , together with the fineness of pitch of the sawlike edges of the tearing strips  4  and the rotational speed of the plate  2 , substantially determines the structure of the ground product.  
         [0042]    As FIG. 8 a  in detail shows, in the exemplary embodiment of FIG. 1 the grinding gap  19  can be varied when the apparatus is at a stop. To that end, the plate  2  is anchored on a shaft  20  by means of a fastening cap  21  via spacer bolts  22  in a driver  23 . By the introduction of at least two spacer bolts  22  into bores of different depths in the driver  23 , the spacing between the plate  2  and the driver  23 , and thus the grinding gap  19 , can be varied. FIG. 8 c  shows a section corresponding to FIG. 8 a  perpendicular to the shaft  20 , along the line C-C. The sectional plane of FIG. 8 a  is represented in FIG. 8 c  by the line A-A. The sectional plane of FIG. 8 b  is represented in FIG. 8 c  by the line B-B. It can be seen from FIG. 8 b  that the bores, shown here in section, in the driver  23  are not filled up by spacer bolts  22  as in FIG. 8 a  but instead are deeper than the bores in the driver  23  of FIG. 8 a . The fastening cap  21  acts centrally on the tearing strips  4 , suspended radially and interchangeably on the end face of the plate  2  with fastening protrusions  24 , and thus acts centrally on the plate  2  as well.  
         [0043]    If the plate  2  is pivoted outward by the pivoting device  13 , then the tearing strips  4  can be changed simply by releasing only a single screw fastening of the fastening cap  21 . The final position of the motor  3  pivoted by 90°, as shown in FIG. 1, is advantageous in this respect. In this position, even without the fastening cap  21 , the tearing strips  4  cannot fall out of the plate  2 .  
         [0044]    For pivoting the motor  3  outward, a screw fastening or fast-action closure between the flange plate  12  and the cylindrical housing  8  is released, and the structural group comprising the motor  3 , flange plate  12 , and plate  2  is pivoted outward by the pivoting device  13  disposed on both sides of the motor  3 . Once a highest position  25  is overcome, this structural group drops into a position  26 . In this position  26 , part of the pivoting device  13  is released, and the motor  3  is pivoted upward by 90° and then locked again in the pivoted position.  
         [0045]    [0045]FIG. 2 shows a cross section through one of the tearing strips  4  disposed radially on the face end of the plate  2  as shown in FIG. 1. As a consequence of the rotation of the plate  2 , a motion of the tearing strip  4  downward in the direction of the arrow  30  is assumed. The part of the tearing strip  4  that protrudes by a height  31  beyond the face end of the plate  2  tears pieces  32  out of a fruit  33  stuffed against it by the feed screw  6 . These pieces  32  are diverted by a groove  34  of rectangular profile disposed upstream, in the direction of the arrow  30 , of the tearing strip  4  in the plate  2 . The groove  34  is open on the circumference of the plate  2 , so that here the pieces  32  can emerge into the annular channel  14  and the discharge chute  15 . What is important is that the mash is mechanically acted upon as little as possible immediately after being separated from the apple, so that the structure of the mash will not be changed.  
         [0046]    The term “wrenching” is understood here to mean a partly combined effect of cutting and tearing. The goal is that the pieces  32  wrenched out of a fruit  33  will have the largest possible free surface area so that many fruit cells will be exposed. A large proportion of the cellular juice can then flow freely out, and a juice extraction and pressing operation subsequently performed on the wrenched product is made easier.  
         [0047]    The cross section shown in FIG. 3 corresponds to that of FIG. 2, but in FIG. 3 one groove each,  35  and  36 , is disposed on either side of the tearing strip  4 . This arrangement has the advantage that pieces  32  wrenched out of the fruit  33  in FIG. 2 are carried away in both directions of rotation during operation of the plate  2 . In other words, the tearing strips  4  can be used on both sides. The tearing strips  4  typically wear down only wherever they are stressed in the travel direction  30  of the plate  2 . If one side becomes dull, then the service life of the tearing strips can be doubled by changing the direction of motion. The grooves  35 ,  36  are rounded, with a radius  37 . This lessens any sticking or wedging of stems and pits of the fruits  33  in the grooves  35 ,  36 .  
         [0048]    The cross section shown in FIG. 4 corresponds to that of FIG. 2, but in FIG. 4 the groove  34 ′ is fully rounded. This prevents unwanted deposits or wedging of pieces of the fruits  33  even better.  
         [0049]    The cross section shown in FIG. 5 also corresponds to that of FIG. 2, but in FIG. 5 the groove  34 ″ is chamfered, which once again prevents solids from wedging in the grooves  34 ″.  
         [0050]    [0050]FIG. 6 shows a cross section A-A of FIG. 1 through the cylindrical housing  8  of the tearing mill, perpendicular to the axis. Three of the four strips  16  can be seen, which extend as a rotation block over the casing length of the housing  8 . The rotation block  17  with the support plate  18  is also shown; it extends over a greater axial range at the outlet  10  of the housing  8  of FIG. 1. The rotation block  17 , with or without counterpart teeth to the tearing strips  4 , has two functions: first, calming the fruits  33  upstream of the tearing strips  4  by reducing rolling motions, resulting in a better mash structure, and second, stripping off fibers that become caught in the tearing strips  4  and are not spun away. The mash structure becomes more uniform, and the power of the drive motors  3  and  11  is used without loss and in a purposeful way.  
         [0051]    [0051]FIG. 7 shows a plan view on the face end of the rotatably supported plate  2  of FIG. 1, with the tearing strips  4  and with immediately adjacent grooves  34  on one side for carrying the product away. The tearing strips  4  are disposed radially, and their extensions meet in the pivot axis  1  of the plate  2 . Arrangements are also possible in which the directions of the tearing strips  4  do not point to the pivot axis  1 . The number of tearing strips  4  is advantageously between approximately 4 and 40. The tearing strips  4  can also have different lengths. The grooves  34  are located upstream of the tearing strips, in terms of the travel direction. The mash leaves the grooves  34  at a radial speed  40  and a circumferential speed  41 , resulting in a speed  42  with an outflow angle  43 .  
         [0052]    [0052]FIG. 9 shows a detail of an interchangeable wear ring  50  on the cylindrical housing  8  of the stuffing device for delivering product in accordance with FIG. 1, in a cross section perpendicular to the housing axis; FIG. 10 shows the same detail in a cross section parallel to the housing axis. Both cross sections pass through a fastening screw  51 , which extends through the wear ring  50  to engage the strip  16 . In FIG. 10, the extension  8 ′ of the housing  8  toward the annular channel  14  of FIG. 1 can also be seen.  
         [0053]    Since with some grinding products for comminution foreign bodies sometimes get into the tearing mill, the edge of the housing  8  is also subject to severe wear at the grinding gap  19  in FIG. 1. Accordingly, the wear ring  50  on the casing of the housing  8  can also be replaced with the screw fastening  51 . The wear ring  50  is advantageously manufactured from a low-wear high-quality steel.  
         [0054]    [0054]FIG. 11 shows a radial section through a detail of an axially adjustable wear ring  50 ′ on the cylindrical housing  8  of the stuffing device for delivering product of FIG. 1. With it, the grinding gap  19  can be adjusted even during operation and automatically. FIG. 12 shows a radial plan view in the direction of the arrows B-B of FIG. 11; the sectional plane of FIG. 11 is marked in FIG. 12 by the arrows C-C. Located along the circumference of the wear ring  50 ′ in the housing  8  are a plurality of slots  511  parallel to the housing axis, by means of which slots bolts  52  screwed into the wear ring  50 ′ are guided. The interior of the housing  8  is sealed off from the outside by two O-rings  53  let into the wear ring  50 ′.  
         [0055]    The bolts  52  also extend through oblique slots  54  in a control ring  55  seated on the outside of the housing  8 . The control ring  55 , on a flange  56 , has a toothed ring  57  driven by a pinion  59  which is driven by a motor  58 . The motor  58  is secured to the jacket of the housing  8  via a flange ring  60 . The grinding gap  19  is increased or decreased in size depending on the direction of rotation of the motor  58 .  
         [0056]    [0056]FIG. 13 shows a diagram of a regulating device with control elements for the tearing mill of FIG. 1 for selecting the structure of the comminuted ground product. Components corresponding to FIG. 1 have the same reference numerals in FIG. 13 as in FIG. 1. For detecting the actual state of the tearing mill, the following sensors are provided in accordance with FIG. 13: a sensor for the power consumption of the drive  3  of the plate  2 , with a signal line  70 ; a sensor for detecting the accelerations upon vibration of the tearing apparatus, with a signal line  71 ; a travel pick-up for the wear ring, for measuring the grinding gap  19 , with a signal line  72 ; and a sensor for the power consumption of the drive  11  of the feed screw  6 , with a signal line  73 .  
         [0057]    As FIG. 13 shows, the signal lines  70 ,  71 ,  72 ,  73  are connected to a regulator  75 . Depending on the actual state and on external specifications via a line  76 , the regulator  75  generates the following specifications for the tearing mill: an rpm specification for the drive  3  of the plate  2 , via a line  77 ; an rpm specification for the drive  11  of the feed screw  6 , via a line  78 ; and a control for the actuator motor  58  for the grinding gap  19 , via a line  79 .  
         [0058]    With the measurement and control variables described thus far, the following regulating and control functions are attained in the apparatus for comminuting organic substances: Closed-loop control circuit for the torque of the drive for the plate  2 . Here the rpm of the plate  2  is specified in fixed form. The torque of the plate drive is measured indirectly through the power consumption, via the line  70 . This torque measurement variable is kept constant by varying the rpm of the feed screw  6 , as a controlling variable. As the rpm of the screw increases, the torque required by the plate drive also increases.  
         [0059]    Variation of the structure of the mash. This structure is varied by adjusting the following parameters during operation of the tearing mill: rpm of the plate  2 , size of the grinding gap  19 , and power consumption of the drive  3  of the plate  2 .  
         [0060]    In accordance with the intended object, the following advantages are attained with the apparatus described thus far: By carrying the mash away in the grooves  34  of the plate  2  and in the annular channel  14  of the housing  8 , the mash structure is not varied or damaged by the effects of congestion. This results in fewer superfine components in the mash, which in fruit presses cause filter clogging and reduce the press performance.  
         [0061]    By means of a wide variability from fine to very coarse in the mash structure, the comminution can be adapted optimally to the pressability and properties of the fruit product. Very soft fruits can accordingly be comminuted very coarsely, while very hard fruits can be comminuted quite finely.  
         [0062]    In comparison with the prior art discussed at the outset, a mill with the present comminuting system operates very quietly with little vibration. Such a mill is also very simple to seal off, if very wet products or products with an overpressure are to be processed. No juice or pressure losses then occur. Tightness of the mill is also highly useful when products with volatile solvents are being processed.  
         [0063]    When fibrous products are processed, mostly separated fibers are spun off from the teeth of the tearing strips  4 . The gaps between teeth do not become plugged with fibers. The tearing performance and the mash structure remain unchanged.  
         [0064]    Wearing parts of the mill can be manufactured simply and economically. When foreign bodies such as stones, pieces of wood and the like are involved, damage remains slight.  
         [0065]    Variants of the described design and the use of the apparatus for comminuting organic substances are readily available to one skilled in the art. For instance, the structure of the comminuted products can be optimized on an ongoing basis automatically in view of an optimal yield/ performance in succeeding pressing operations with the control and regulating means disclosed.