US3027101A - Milling apparatus - Google Patents

Description

March 27, 1962 N. szAs z MILLING APPARATUS 2 Sheets-Sheet 1 Filed May 22, 1958 BY KSZASZ ADM w smfifi 72%; C. W

ATTORNEY mm Om m oE March 27, 1962 N. SZASZ MILLING APPARATUS 2 Sheets-Sheet 2 INVENTOR.

NANDQR $ZASZ y Mm ADMINIZIICRAT X 1 ATTORNEY Filed May 22. 1958 iilnited rates Fatent @fifice 3,027,101 Patented Mar. 27, 1962 This invention relates to milling apparatus and more particularly to an improved compact flour milling installation and the construction of special stacked units for such an installation.

Some attempts have been made in the prior art to arrange flour milling apparatus in a stack or frame in which the stock is fed to successive breaking or reduction rolls and intermediate sifting devices. One such unit is shown, for example, in Buchholz United States Patent 97,038, in which reciprocating sifters are mounted in a stack between successive sets of milling rolls. Stacked milling units of this type have not been used extensively. Mechanical difliculties were apparently encountered. Also, modern milling emphasis on the use of air purifiers and gyratory sifters and on complex flows for greater extraction have required an abundance of equipment, and the use of large mill buildings, which are often many stories high in order to minimize mechanical conveying by more extensive vertical conveying of the stocks. Thus such stacked mills never achieved substantial popularity or utility.

With the problems of the prior art in mind, it is one object of the present invention to provide an improved stacked milling unit.

Another object is the provision of an improved arrangement of reciprocating sifters.

It is a further object to provide a stacked milling unit in which reciprocating sifters are arranged in a particular manner with associated milling machines.

Another object is a stacked mill arrangement in which undesired vibrations and bending forces on the frame are reduced to a minimum.

A further object is an improved roller mill unit of minimum vertical height.

Still another object is an improved roller mill unit which can be hung from a supporting frame to eliminate the bulk of a conventional bottom support.

Other objects and advantages will be apparent from the following specification, in which certain preferred embodiments of the invention are described. In the drawings which form a part of this application- FIGURE 1 is a side elevation of a single milling unit stack according to the present invention;

FIG. 2 is a partial perspective view of one of the re ciprocating sifters of the stack of FIG. 1;

FIG. 3 is a partial View showing details of the driving mechanism for the sifters;

FIG. 4 is a front View of an improved roller mill unit of minimum vertical height;

FIG. 5 is a sectional view along the line 55 of one end of the device of FIG. 4; and

FIG. 6 is an end View of the opposite end of the unit of FIG. 4, with certain portions broken away for clarity.

As shown in FIG. 1, the invention contemplates the use of a supporting frame indicated generally at 10, which includes a central supporting section 12, and oppositely extending end sections 14 and 16 which are in longitudinal alignment with each other and with the greater center section 12. The center support section may include at least two pairs of vertically extending columns 18 and 20, with one column of each pair at each side of the machine. The respective end support sections include at least one pair of vertical columns 22 for end section 14 2 and a pair of vertical columns 24 for section 16. Upper connecting beams 26 rigidly connect the various vertical columns. Additional longitudinal braces 28 interconnect the columns 18 and 22, while further beams 30 connect columns 20 and 24.

According to the present invention, one or more pairs of reciprocating classifying units are mounted in the respective frame portions. These classifying units are arranged in pairs. As shown in FIG. 1, for example, the uppermost sifters 32 and 34 form a first pair, the next I lower classifying units 36 and 38 form a second pair, the

next lower classifying units 40 and 42 form a third pair, and the lowest classifying units 44 and 46 constitute a fourth pair. The individual classifying units of each pair are arranged in longitudinal alignment with each other and extend from the central support portion of the frame into the opposite end sections of the frame.

As a practical matter it is particularly desirable to arrange the units so that they feed their stocks in opposite directions. Thus either their respective receiving ends or their discharge ends will be adjacent each other at the center portion of the frame. In such a case, as noted below, when the respective classifiers or sifters of each pair are reciprocated in counterbalancing opposition, a conveying stroke will be balanced against a conveying stroke and a return stroke against a return stroke.

It is also possible, especially where the weights of the respective stocks are relatively small compared to the weights of the classifiers themselves, to have the classifiers of each pair feed in the same direction, while they are reciprocated in counterbalancing opposition.

The respective pairs of classifiers are adapted to be driven or reciprocated in counterbalancing opposition to each other by several drive shafts 48, 50-, 52, and 54. Shaft 48, for example, is driven by a motor 56 through an intermediate belt 58. A further belt connection 60 drives the shaft 50 from shaft 48 through the same motor '56.. Similarly, shaft 52 is driven by a motor 62 through belt 64. A further belt 66 drives shaft 54 from shaft '52. These drive shafts are arranged so that one shaft serves as a common drive for both sifters of a given pair. The shafts are thus located conveniently at the center of the frame, between the respective Sifters of each pair.

The individual classifying units are supported, in known manner, by suitable hangers 63 and 72, to provide the desired reciprocating vibratory movement. As shown in detail in FIGS. 1 and 2, sifter 32 is pivotally connected at 69 to the lower ends of one pair of hangers 68 (only one of which is shown). The upper end of this hanger is pivotally carried by a supporting bracket 70 on the center supporting frame 12. Similarly, the hanger 72 at the opposite end of sifter 32 is carried by a bracket 74 on the end frame. The respective classifiers include suitable sifting surfaces, such as the screen 76 shown in FIGS. 1 and 2, for classifier 32. This screen surface is supported within the body 78 of the sifter and is adapted to receive stock fed into the receiving end 92 of the sifter through an inlet 80. Suitable reciprocation of unit 32 is adapted to convey the stock from this receiving end to the opposite or discharge end 94 of the unit and to sift the desired particles down through the screen surface 76.

The desired reciprocatory movement is given to classifier 32 in known manner by a connecting rod 82, which is pivotally connected at 84 to the sifter. The other end of connecting rod 82 includes an eccentric 86 (FIG. 3) driven by shaft 48. A similar eccentric 88 on a connecting rod 90 drives the opposite classifier 34 of this first pair. The eccentrics are arranged exactly opposite each other so that the respective sifters are at all times moved in counterbalancing opposition, i.e., either toward each other or away from each other. Thus the movemerits of the respective sifting units tend to cancel each other and to minimize the effective vibrations transmitted to the frame. As set forth above, this balancing of vibrations is further enhanced if the directions of feed on the respective classifiers of a given pair are opposite to each other. In that case, a conveying stroke is opposed to a conveying stroke and a return stroke to a return stroke. The feeding of substantially equivalent weights and types of stock to each sitter of an opposing pair further insures the balancing of horizontal forces and the reduction or elimination of forces tending to deflect the vertical coltunns of the frame. Greater flexibility of processing iiow, however, may be obtained by operating on different desired stocks. Where the stocks provide only a fraction of the total weight of each sifter, one may process different types and weights of stock on the respective sifters of a given pair in order to achieve such flexibility. One may also add weight to one sifter or the other to balance the total weights of the opposed units for flows of different stock weight or to compensate for different sifter weights due to construction details. These arrangements and the use of opposed eccentrics on common drive shafts thus counterbalance the major forces involved.

The frequency and amplitude of the reciprocatory vibrations, and their direction as determined by the angular orientation of hangers 68 and 72, are adapted to convey the stock in known manner from the receiving end to the discharge end of each classifying unit. Thus in unit 32 the material is received at the inner receiving end 92 at the central frame area and conveyed to the outer end portion of the frame across the sifting surface 76. The material which stays above the screen is then discharged at 94, while the material which passes downwardly through screen 76 is separately discharged at 96. A similar discharge 97 is shown on classifier 34, and the remaining sifting units may be similarly constructed. A single sifting surface 76 has been shown for purposes of illustration. Additional surfaces and separate discharge spouts for stocks segregated by such surfaces may be used as desired, provided the opposing units of a given pair are of essentially similar weight and construction.

According to a further feature of the invention, a plurality of pairs of milling units, such as breaking or reduction machines, are also mounted on the supporting frame. Thus a first pair of such units 98, illustrated as individual roller mills 100 and 102 are mounted at the top of the central frame section. These units are further designated by symbols 1A and IE to show that they are adapted to perform initial milling operations on two portions of stocks A and B. Different stocks may be used, and different initial operations carried out at 1A and 1B. The stock to be milled on unit 100 is introduced at 104 and the stock to be milled on unit 102 is introduced at 106. These first units 100 and 102 then discharge their respective milled products at 108 and 110, respectively, into the receiving ends of the uppermost pair of opposed sifters, 32 and 34.

A second pair of milling units is provided, consisting, for example, of second roller mill units 112 and 114 mounted on the respective outer frame portions 22 and 24 to receive the tailings from the respective sifters 32 and 34. The milling units of this second pair perform desired operations, as designated 2A and 2B, on their respective stocks, and then discharge directly into the receiving ends of the next pair of classifiers, 36 and 38.

A third pair of milling machines 116 and 118 are mounted in the central portion of the frame to receive the tailings from sifters 36 and 38, to perform desired third milling operations 3A, 313 on the respective streams, and to discharge the materials processed by such machines into the receiving ends of the next lower sifters 40 and 42.

Finally, a fourth pair of milling machines, illustrated as roller milling units 120 and 122, are mounted at the outer frame portions 22 and 24 to receive the tailings from sifters 40 and 42, to perform other milling operations at 4A and 4B on the respective tailings, and to discharge their processed stocks into the receiving ends of the lowest pair of sifters 44 and 46. The tailings of these sifters are then discharged at 123 for any suitable further processing.

The pairs of milling units are illustrated as each including a single pair of rolls in special housing and support, as described below. These rolls 124 and their housing are provided with suitable supporting flanges or pads 126 which can be bolted at 128 to the supporting columns of the frame. A driving pulley 130 on one of the rolls is connected by a suitable belt 132 to the drive pulley 134 of a motor 136. in this case the respective roller milling units are driven in pairs and motor 136 thus also drives the lower unit 116 by a belt 138. Similarly, a single motor 140 at each end of the frame drives the remaining units. For example, motor 140 is connected by belt 142 to the roll unit 112, and by belt 144 to milling unit 120. Similar drive motors are connected to units 102 and 118 and units 114 and 122 at the other sections of the stack.

The stacked unit illustrated in FIG. 1 is designed for use in suitable classifying operations of a flour milling process. As suggested above, different stocks can be fed through the respective sections 1A, 2A, 3A and 4A on the one hand, and sections 18, 2B, 3B, and 4B on the other, to perform different processing steps on different stocks. For example, units 1A, 2A, 3A and 4A could perform successive breaking operations on grain introduced at 104, while units 13, 2B, 3B and 413 could perform successive reduction operations on stocks introduced at 106. Stocks from other sources can be added at desired points.

If one decides to perform identical operations on similar stocks at each step of the apparatus of FIG. 1, the desired initial stock may be fed from a common source, and separated by a suitable divider or stream splitter, as shown schematically at 167, so that substantially equal quantities or volume rates of the same stock are fed to each of the respective initial units 1A and 1B, for essen-' tially similar operations. For example, such a stacked unit might be used to perform four successive breaking operations with intermediate scalping or sifting of the stocks, and with identical clean wheat fed to each of the first units at 104 and 106. Or the unit could receive equal amounts of a given middlings stock at 104 and 106 and perform successive reduction and classifying operations at the respective steps. In any such case, the use of two identical pairs of rolls or units at each step, and the division of the initial feed at 167 equally between the first rolls provides a particularly advantageous milling unit in which undesired vibrations are reduced to a minimum and in which each of the pairs of opposed sifters carries essentially the same load as its opposite member. Thus a well-balanced, compact unit with minimum vibration is achieved.

According to a further feature of the present invention, a special form of milling roll unit is provided which can be mounted in novel fashion on the vertical columns at the center and ends of the stacked unit. These milling machines are provided with special casings having supporting means on the back walls. Thus the machines can be hung or supported by attaching these back wall portions to vertical columns or other frame members.

As distinguished from conventional milling rolls which have a heavy bottom support arrangement, the units of the present invention have a minimum vertical height. Thus, they can be fitted between upper and lower classifying or other processing units, which can be spaced vertically much more closely than could be achieved with conventional roll stands.

Such roller mill units are also arranged so that all controls and drives are on their front or end walls and necessary adjustments and repairs can be made while the units remain in position on a stack or frame with sifters located immediately above and below them. Finally,

the particular mounting of these units makes it possible to remove an individual machine from the stock or frame and replace it by another similar unit to permit convenient repair and maintenance work on the removed unit without unnecessary interruption of the operation of the complete stacked unit.

Details of these individual roller mills are shown in FIGS. 4, 5, and 6, with particular reference to the unit 112 of FIG. 1. Roller mill 112 includes a casing or housing portion indicated generally at 146. This housing includes end support sections 148 and 150 in which suitable bearings for the milling rolls are carried. The central portion of the housing at 152 encloses the milling rolls themselves.

An indicated above, the unit is adapted to be supported by means on the rear wall 154 of the unit. Such supporting means include lower and upper supporting pads 126 and 128, respectively, on the end portion 148 of the easing, and similar supporting pads 156 and 158 on the opposite end portion 150. These supporting pads are provided with a plurality of openings 160 through which retaining bolts 162 are inserted to secure the supporting pads to appropriate frame members of the stacked unit, such as vertical columns 22. Y

The respective end portions 148 and 150 preferably include supporting walls or webs 164 and 166, in which suitable bearings 168 are provided to support the shafts 170 and 172 of the respective milling rolls 174 and 176. The bearings may be removable in known manner to permit removal of the individual milling rolls for replacement or repair. These supporting webs or walls 164 and 166 are preferably located opposite the respective supporting pads to provide a direct supporting connection between the supporting pads and the bearing supports in the casing. The casing itself is cast or otherwise constructed to provide walls and ribs of appropriate thickness to support the roll bearings from the rear wall supporting pads.

As shown in FIG. 4, one of the roll shafts 170 projects outwardly beyond at least one end wall or cap 178 of the casing and is provided with a suitable pulley or sheave 180 adapted to be driven by belt 142. At the opposite end of the casing at 150, suitable connections can be provided to obtain the desired differential speeds for the respective rolls. Thus the roller shafts 170 and 172 carry respective sprockets 182 and 184 which are interconnected by a suitable driving chain 186. This chain may pass over the two sprockets on the roll shafts and over additional idler sprockets 188 and 190 mounted on the supporting wall 166 as shown. A removable end plate 192 closes the end 159 of the housing and provides convenient access to the diiferential mechanism as needed.

To feed the stock to the rolls, a suitable inlet opening 194 is provided in the top wall of the central casing portion above the rolls. A suitable inlet tube or hopper 196 may be added to connect this opening 194 to the discharge end of a suitable sifter or to any other source of material for the milling unit 112. The inlet opening and tube may be of conventional circular configuration, located at the center of the top wall. In this case, however, a hopper of elongated cross section is shown. Thus the material discharged by a sifting unit just above the roller mill 112, as the sifter 32 of FIG. 1, may already be distributed over a width equivalent to that of the milling rolls. The use of a wide or elongated inlet and hopper at 194 and 196 takes advantage of such distribution and imposes a smaller burden of distribution on the feeding mechanism of the roller mill itself. The stock received through opening 194 is further distributed by a suitable feed roller 198 in known manner, so that an even layer of material is fed between the milling rolls 174 and 176.

Immediately below the milling rolls the bottom wall 200 of the casing includes a laterally extending opening 202 through which the material is discharged directly by gravity. To guide the material from this bottom opening to a subsequent processing unit, the bottom wall is also provided with supporting brackets 204, to which a discharge hopper 206 may be secured by bolts 208. Hopper 206 and bottom opening 202 are also illustrated with elongated cross sections to retain the lateral distribution of the stock, if desired, as the stock is fed to a subsequent processing unit. In such case, the inlet of the subsequent unit should be of generally similar width. Thus the lateral distribution of the stock can be maintained throughout a series of enclosed processing units as illustrated by the closed reciprocating sifter bodies and the closed roller mill casings.

The milling machine includes one or more adjusting wheels 210 and 212 at its front wall 214 for convenient adjustment of the roll spacing or roll throwout mechanism in known manner. The front wall 214 also includes a removable or transparent inspection door 216 through which a miller may check the condition of the stock leaving the rolls. Another removable cover .218 is located at the upper portion of the casing for inspection of the operation of the feeding mechanism 198 or, in appropriate cases, for actual removal of the rolls in known manner. Automatic roll throwout mechanism, automatic feed control and other features of conventional roller mills may also be incorporated as needed or desired.

Thus a convenient roller milling unit has been provided in which a single pair of milling rolls is mounted with appropriate driving mechanism in a single housing and the rear wall of the housing is provided with supporting means by which the unit can be hung on a suitable frame member with minimum vertical clearance between upper and lower processing units.

According to the foregoing description, a compact stacked mill unit has been described which is particularly advantageous in the milling of wheat and other grains. Such a unit provides a plurality of reciprocating sifters in a compact frame, with the sitters supported in pairs for reciprocation in counter-balancing opposition to each other. The special roller mill housing and construction features and the arrangements for supporting such roller mills by suspension of their rear walls from a stack or frame contribute to an improved installation in which stock may be subjected to a series of milling operations with minimum intermediate handling. The short vertical height of such roller milling units contributes to an assembly in which direct gravity flow of material may take place through a substantial number of vertically spaced milling and classifying units to provide an enclosed processing system of minimum overall height. The present specification has accordingly set forth certain of the principles of the present invention and some of the Ways in which the invention may be put into practice.

Now, therefore, what is claimed is:

l. A stacked fiour milling unit for a grain milling installation, said unit comprising a supporting frame having aligned center and end portions, a pair of first roller milling machines, each machine having a pair of milling rolls, said machines being mounted at the top of said center portion, means for feeding desired stocks to each of said machines, two opposed and aligned first longitudinally reciprocating substantially horizontal classifiers supported on said frame beneath said first rolls and extending outwardly toward said end portions, means for reciprocating said first classifiers in counterbalancing opposition to each other and thereby separately moving stock received from the respective first roller milling machines outwardly to the end portions while the stock is at least partially classified, a pair of second roller milling machines located one at each end portion of the frame in position immediately below said first classifiers to receive desired stock by direct gravity discharge from the outer ends of the respective first classifiers, a second pair of opposed and aligned longitudinally reciprocating substantially horizontal classifiers supported on said frame independently of said first classifiers with their outer receiving ends immediately beneath said second roller milling machines and extending inwardly toward said center portion, means for reciprocating said second classifiers in counterbalancing opposition to each other and thereby separately moving the stock received from the respective second roller milling machines inwardly to the center portion of the frame, while further classifying said stock, a third pair of roller milling machines mounted on the central frame portion, means for feeding stock from the inner ends of said second classifiers into their respective third roller milling machines, a third pair of opposed and aligned longitudinally reciprocating substantially horizontal classifiers supported on said frame beneath said third roller milling machines and extending from said center portion outwardly to the respective end portions, means for reciprocating said third classifiers in counterbalancing opposition to each other and thereby separately moving the stock received from the respective third roller milling machines outwardly to the end portions while the stock is further classified, two fourth roller milling machines mounted one at each end portion of the frame in position immediately below the third classifiers to receive desired stock by direct gravity discharge from the outer ends of the respective third classifiers, a fourth pair of opposed and aligned longitudinally reciprocating substantially horizontal classifiers supported on said frame immediately beneath said fourth pair of rolls, and means for reciprocating said fourth classifiers in counterbalancing opposition to each other and thereby separately moving the stock received from the respective fourth roller milling machines inwardly to the center portion of the frame while further classifying said stock.

2. A stacked flour milling unit according to claim 1 in which said third pair of roller milling units is mounted on the central frame portion at a location positioned below the inner ends of the second pair of classifiers to receive stocks therefrom by direct gravity discharge, said third pair of milling units also being positioned immediately above the inner ends of the third pair of classifiers to deliver stocks thereto by direct gravity discharge.

3. A stacked flour milling unit according to claim 1 in which said means for feeding stocks to each of the first pair of roller milling units includes means for receiving a single type of stock and dividing it to feed such stock to each of said first milling units at substantially equal volume rates.

4. A grain milling installation for performing a series of break operations comprising at least one stacked flour milling unit according to claim 1, said unit having four pairs of break roller milling machines, one pair for each of first, second, third and fourth break operations.

5. A grain milling installation for performing a series of reduction operations comprising at least one stacked flour milling unit according to claim 1, said unit having four pairs of reduction roller milling machines, one pair for each of four successive reduction operations.

References Cited in the file of this patent UNITED STATES PATENTS 97,038 Buchholz Nov. 23, 1869 263,164 Gilbert et al. Aug. 22, 1882 267,347 Hollingsworth Nov. 14, 1882 505,723 Pollock Sept. 26, 1893 806,865 Benesh Dec. 12, 1905 1,377,976 Smith May 10, 1921 2,081,283 Ryan et al. May 25, 1937 2,085,376 Maede June 29, 1937 FOREIGN PATENTS 4,478 Great Britain of 1908 13,101 Great Britain of 1891 197,266 Switzerland July 16, 1938 764,643 France Mar. 12, 1934

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