US2159549A - Sifter - Google Patents

Description

May 23, .1939. T. G. CECKA. 2,159,549

SIFTER Fil ed June 25, 1936 5 Sheets-Sheet 1 INVENTOR AT TOR N EYS Patented May 23, 1939 UNITED- STATES PATENT or -Pics Thomas G. Oecka, Buitalo, N. 1., assignor to mtel-national Milling Company, Buflalo, N. Y.

Application June 25, 1936, Serial No. 87,198

11 Claims (01. 209-325) This invention relates to improvements in sitters.

One of the objects of this invention is to improve the construction of sitters to increase the capacity and efliciency thereof. Another object is to greatly increase the capacity and emciency of sitters by operatingthe same at a speed-0t approximately 300 revolutions per minute in a closed loop path having a substantial radius not -materially exceeding one inch. It is also an ob- :Iect otthis invention to greatly increase the capacity ot sitters by operating the same at a materially higher speed and smaller radius of throw than was heretotore done. Another object of the 1 invention is to provide a sitter in which the sieve or screen is given a rotary motion in a direction approximately parallel to its surface, and also a motion approximately at a right angle to said surface. Another object is to provide a sitter in go which the sieve orscreen has imparted to it a circular motion, and in which the screen or sieve is yieldingly or flexibly supported to permit the same to move in a direction at .an angle to the plane of the circular motion.

Another object of this invention is to provide the sieve or screen at a sitter with a rapid motion in a plane approximately parallel to its base to provide tor a movement of the material to be sifted across the surface of the sieve, and also to provide the sieve with a motion toward and from the material to be sifted to produce a motion of the material toward and from the surface of the sieve. Another object of the invention is to provide an improved flexible mounting for a sitter housing trom a base or support below the housing.

Still another object of this invention is to pro-- vide a sitter which may be of relatively small size, and in which the sieves may be supported from the base of the machine and provided with sieve and at an angle thereto; Another object of this invention is to provide a'resilient support tor a sieve ot a sitter to permit movement of the sieve in a direction lengthwise of the support.

- A further object of this invention is to provide a sitter which is so formed that a plurality of difterent materials or grades of materials, can be simultaneously'sitted without mixing or intermingling of the materials or grades.

movements approximately in the plane of the Other objects of this invention will appear from plan view thereof, partly in secing, on line 55, Fig. 2.

Fig. 6 is a fragmentary sectional elevation thereof, on line 6-6, Fig. 2.

Fig. 7. is a fragmentary sectional elevation of the means for transmitting rotary motion to the sitter housing.

The word sitter as herein employed is intended to indicate an apparatus for sitting, screening or bolting flour or other finely divided or granular materials torseparating the same according to their particle sizes. The sitter shown in the accompanying drawings illustrates by way of example one embodiment of my invention and it is not intended to limit this invention to'the particular construction or form of sitter shown in the drawings- I My improved sitter may operate in connection with sieves or screens of any suitable or desired construction and any desired number of such sizes. In the construction shown-in the drawings, a group of sieves is provided to which the material to be sifted may be supplied through a pair of flexible tubes or ducts ill extending I through the cover or top H of the sieve housing. The sieve housing is provided at opposite sides with discharge tubes or ducts It for the line ma-' terial passing through the sieves, and II reprethe overs or tailings which have not passed through the sieves, these ducts in the construction shown being connected with a bottom member it of the sieve housing.

The sieve housing contains one or more sieves upon the upper face of which the material to be sifted is deposited, and these sieves may be mounted within the sieve housing in any suitable or desired manner. In the particular construction illustrated, the sieve housing is formed of a number of sieve frames If, each of which has an imperforate outer wall, the walls of the several sieve frames. being connected by dust-tight sents similar tubes or ducts-tor the discharge of gaskets I8 of any suitable material, such for example as mohair. The several sieve frames may be held in correct relation to eachother in any suitable or'desired manner to form the dust- 5 tight side walls of the sieve housing. For example, the 'bottom- I2 of the sieve housing may 'be provided with an-upwardly extending case or frame member. 20, formed to engage at least the corner portions of the sieve frames I1 and to .1 'hold ,the same in proper relation to each other. This case or frame member as. shownis made of sheet metal and has V shaped openings 2| 'at opposite'sides thereof to facilitateaccess to the sieve frames I1 for positioning them within or removing them from the case-or frame 20. When the desired number of sieve frames I! have been placed or positioned within the case or frame 20, 'the cover or top-II. is placed on the uppermost sieve frame I I and downward pressure is applied 20 thereto to press the sieve frames into their operative positions. This may be done by means of clamping bolts 22 and nuts 28,-the clamping to pressthe cover or top II downwardly against the upper sieve frame "and thus press all of the sieve frames into dust-tight relation to each other. v a r The sieve frames I! may be constructed in any suitable or desired manner, and as shown each sieve frame is provided with an inner sieve supporting frame 21 to the upper edges of which-a screen or sieve 28, of any. suitable material is The inner, sieve supporting frame 21 has three sides thereof spaced from the outer sieve frame I'I, while at the fourth side, the inner frame 21 is secureddirectly to the outer frame I'|. Be-

low the sieve 28 is provided-the usual coarse wire screen 28 upon which the usual cleaning brush 5 (notshown) may be supported which moves along the undersurface of :thesieve 28 and prevents plugging of the meshes of the sieve. Below the coarse wire mesh screen 29 is provided an imperforate deflector plate or tray 80. that shown in 5 the accompanying drawings, see particularly Fig.

7- 6, inclining downwardly from the longitudinal center ofthe sieve frame 21 towardv opposite sides thereof and-terminating at its sides in slots 8| formed in opposite sides of the inner screen frame 55 21.. These slots terminate in the spaces 32 arranged at opposite sides of, the screen frames between the outer frames I1 and the inner frames 21. Since these spaces 82 of successive sieve frames I! are arranged in vertical alinement, the

a0 material which has passed through the sieves 28 and on the trays 80 will drop through the alined r spaces 82 to the bottom I2 of the sieve housing and will pass out of the sifter through the tubes or ducts II, see particularly Fig. 6. The material as whichdoes not pass through a sieve 28 is rapidly passed by the movement of the sifter housing to the end of the sieve 28 and drops beyond the end of the inner frame member 21 through a space 84 between the inner and outer sieve frames 21 and a 70 I1 uponone end of the next lower sieve 28, from through any of the sieves 28 is discharged from the sifter through the flexible tubes or ducts Il.

In order to expedite the passage of the material across the sieves 28, particularly when the sieves are arranged horizontally as shown, carrier flights 5 36 (Fig. 6), which may be in the form of short t metal plates are provided above each sieve to deflect the material across the sieve and toward the'discharge end thereof during the rotary motion of the sieve housing. In the construction-10 shown, the carrier flights are secured to the sieve frames 2Ibelow the trays, so that when the sieve frames are arranged one above the other. the

- carrier flights of one sieve frame will be arranged above the sieve 28 of the next lower sieve frame. l5

' In the particular construction shown, each inner sieve frame is provided with longitudinally extending central walls or partitions 3-1 and transversely extending partitions 38, both of which serve as supports for the sieves 28. The longitudinally extending walls or partitions 31 may be of approximately the height of the outer walls of the sieve frames I1 and are arranged one above the other in vertical alinement to form an imperforate dividing wall in the middle of the sifter, so that each side of the sifter operates substantially independently of the other.

The sifter arrangement described is desirable in that different materials may be simultaneously sifted in the two sides without any mixing of the materials. In my improved sifter, the distance or clearance between a sieve 28 and the imperforate tray 30 of a superimposed sieve frame is made greater than in sifters heretofore made to accommodate the larger quantity of material which my improved sifter -is capable of handling and by arranging the trays 80 so as to deflect material toward opposite sides of the sifter, the capacity of the sifter is also increased. The cover or top I I of the sieve housing is. of course, also provided with suitable downwardly extending walls or partitions 39 to confine the material to be sifted to the top surface of the upper sieve 28 and to prevent the same from passing through the upright d cts or spaces 32 with the fine material which has through the sieves 28. A further partition 40 in alinement with the central longitudinal walls or partitions 31, completes the separation of the two halves of the sifter housing.

In the use of the sifter, the sieve frames II can, of course, be readily removed by releasing the clamping nuts 23 and these frames I! can be replaced by other frames having sieves 28 of diiferent meshes, and if a smaller number of sieves is required, sieve frames I I not provided with sieves 28, screens 28, and trays 80 can be used to ill] in the space of the sieves not required, as was customary heretofore in sifters.

43 represents, horizontal braces or spacing rods,

the ends of which are secured to the comer brackets 24, for reinforcing the upper portion of the sieve housing. g

I have found that in the operation of a sifter, a very greatly increased capacity and higher efliciency can be obtained if the housing containing the sieves is flexibly and resiliently, mounted in such a manner that when a circular motion isimparted to the sieve housing, this housing is 'free to move in other directions than the. direction of circular movement imparted to it by a suitable driving mechanism. For example, in connection with the housing which has been described, greatly increased efficiency and capacity of the machine can be obtained if, in addition to imparting a movement in a circular direction to the sieve 76 the same, on which base the drive mechanism for.

' ported from beneath the sieve housing, since from a practical standpoint it is more desirable to support the sievehousing from a base arranged below imparting circular motion to the housing may also be mounted. I have illustrated my invention, by way of example, *by means of a sifter mounted in this manner upon a base which maybe of substantially unitary construction and provided with outwardly extendinglegs 45. These legs may be provided with suitable apertured lugs 46 by means of which the sifter may be bolted to a floor.

The legs 45 of the base extend below the corners of the sieve housing and are constructed to receive the lower ends of flexible and elastic supports, capable-of yielding to permit lateral movement of the sieve housing and also resilient or elastic to permit a limited up and down movement of the sieve housing. Any suitable supports having these properties may be employed. In the particular construction shown, I employ a plurality of flexible rods or reeds 4'! of wood, such as have heretofore been used for suspending sifters from overhead supports, but since such reeds have practically no elasticity or resilience,

I supplement such reeds with some elastic or resilient means, which may conveniently be provided at either the upper orlower ends thereof. In the construction illustrated, the upper ends of the reeds 41 are suitably secured by clamps 48 to the corner brackets 24 of the case or frame 20 of the sieve housing. The legs 45 are provided with upwardly extending studs 50 secured thereto, and'a sleeve SI of resilient material connects the studs 50 with the lower ends of the reedsll. The resilient sleeve may be secured to the studs 50 and the reeds by means of suitable clamps 52 and 53 arranged respectively about the upper and lower portions of the flexible sleeves 5|.

. These sleeves may be made of rubber, and if desired, they may be reinforced by means of fabric or canvas. Short lengths of steam hose have,

for example, been found very satisfactory to form the resilient parts of the supports. The studs 50 may be roughened as indicated by 54 to better secure the sleeves thereto. Because of the flexibility of the sleeves, the relatively short reeds 31 do not break when the machine is in operation, since most of the flexing as well as all of the stretching takes place in the sleeves' The base ofthe apparatus may also form a support for the driving connectionfor the sieve housing. In the particular construction shown, the base is provided with an upwardly extending central part or hollow post 55, in which a bearing is formed for the lower part of an upright crank or eccentric shaft 56, suitable ball or roller bearings 51 and 58 being shown for this purpose. The shaft 55 has a drive wheel or pulley 59 secured thereon above thepost 55 of the base. The shaft also has an upwardly extending crank or eccentric portion 60 which extends into a selfaligning bearing 8| suitably. arranged in a bearimghousing 62 secured to the base H of the sieve any suitable or. desired construction and the 'crank oreccentric 60 has a slidable fit within this bearing, so. that the bearing may move; up

and down-relatively to the crank or eccentric 60'.

The pulley or drive wheel 59 may be driven ,vertically arranged motor, 85 and in order to reduce vibration of the sifter, a counterweight 66 may be provided which is disposed diametrically opposite to the crank or eccentric 80 of the upright drive shaft. The motor 65 in the construction shown is secured to a suitable bracket 61 which may be formed integrally with the base of the sifter. It will, of course, be understood that any other means for imparting circular or.

horizontal motion to the screen housing may be employed in place of the particular mechanism shown.

is also restricted or limited by the resilient connectors, so that the upright movement cannot become excessive so as to interfere with the efficient operation of the machine.

It has, for example, been found that if the sifter is built of a size so that the entire surface of each of the sieves 2B is somewhere in the neighborhood of twenty inches square, and if the eccentric or cam 58 has a two-inch throw, or, in other words, travels in a circle of about two inches diameter, at approximately 290 to 310 revolutions per minute, the flexible steam hose mountings 5! will stretch about of an inch during each revolution of the driving shaft, thus producing an up and down movement in addition to the circuar movement of the sieve housing. Asifter of these proportions has a capacity of approximately three times that of any sifters nowv in use per unit of sieve area. This increase found that the coarse material is thrown upwardly to the upper surface of the material upon the sieves, so that this coarse material will not tend to block or-plug the meshes in the sieves. It has also been found that a sifter of the size above stated and equipped with ten sieves, requires approximately one-quarter of a horse power to drive it at a speed of 300 revolutions per minute, so that the sifter is extremely eflicient and economical in the use of power.

I claim as my invention:

1. A sifter including a base, a sieve housing arranged above said base, power driven mechanism mounted on said base for imparting movement in a circular direction to the lower portion of said housing, flexible rods extending upwardly from said base and secured to the upper portion of said housing, and a resilient sleeve connecting said base and each of said rods and permitting' said rods to move toward and from said base.

2. A sifter including a base, a sieve housing arranged above said base, mechanism mounted on said base for imparting movement to said housing, including a shaft journalled in said base and having a crank portion, a self-alining bearing secured to the bottom of said housing'and into which said crankportion of said shaft extends, means for rotating said shaft, flexible rods having their upper ends secured to the upper portion of said housing, and elastic sleeves each of which has one endsecured to said base and the other end secured to the lower portion of a rod.

cular motion thereof and also movement in an up and down direction.

4. A sifter having a sieve housing containing a sieve upon which material to be sifted is depos-' ited, means for imparting rotary-motion in a substantially horizontal plane to the lower portion only of said sieve housing at speed of approximately 300 revolutions per minute and on a radius of approximately one inch, 9. fixed base above which said housing is arra ed, and means extending upwardly from said flx e dbase for supporting said housing, the upper portion of said supporting means being movable in a circular direction, said supporting means also being resilient to permit slight vertical movement of said housing.

5. A sifter having a sieve housing containing a sieve upon which material to be sifted is deposited, means for imparting rotary motion in a substantially horizontal plane to the lower portion only of said sieve housing at a speed of approximately 300 revolutions per minute and on a radius of approximately one inch, a base above which said housing is arranged, reeds extending upwardly from said base and secured to said base v and to said housing, the upper portions of said reeds being movable inapproximately horizontal circular paths.

6 A support fora sifter housing including a slender flexible rod forming a connection between a supporting structure anda sifter housing, and a resilient member having a part thereof secured to said supporting structure and another part secured to one end of said rod, and forming the sole connection between said rod and said supporting structure, to permit said support to yield in the direction of its length, said resilient memher also flexing to enable said rod to swing relatively to said supporting structure.

7. A support for a sitter housing, including a slender flexible rod forming a. connection between a supporting structure and the housing and having an elastic sleeve into one end of which an end of said rod extends, the other end of said sleeve being secured to said supporting structure, said sleeve forming the sole connection between said rod and said supporting'structure.

8. A method of sifting material which comprises placing upon the upper surface'of a sieve the material to be sifted, imparting to the sieve motion in a substantially horizontal direction and in a circular path of approximately one inch radius and at a speed of about 300 R. P. M., and

also moving said sieve to a limited extent in an up and down direction during each of. said rev-' olutions. r

9.' A sieve including a frame having screening material secured thereto in a position to support the material tobe sifted on the upper face therei in said circular path of. about one inch radius of, a plurality of short plates extending above almanac said screening material and in close proximity thereto for advancing the material tobe sifted across saidscreening material during movement of the sieve, a coarse mesh screen arranged below and substantially parallel to said screening material for supporting a cleaning member for engaging the underneath surface of said screening material for cleaning the same, and means for imparting movement to said sieve in a substantially .circular path approaching but not materially more than about one inch radius at a speed of about 300 revolutions per minute.

10., A method of sifting material which comprises placing upon the upper surface of a sieve the material to be sifted, and imparting to the sieve 'motion in a substantially horizontal direction and in a closed loop path of a width approaching but not materially more than about two inches across and at a speed of about 300 R. PFM.

11. A method of sifting material which comprises placing upon the upper surface of a sieve the material to be sifted, and imparting to the sieve motion ina substantially horizontal direction and in an approximately circular path of about one .inch radius and at a speed of approximately 290 R. P. M. to 310 R. P. M.

12. -A sifter having a sieve disposed to receive and support a material to be sifted and tosift said material upon approximately horizontal lateral movement of the sieve, means yieldingly supporting said sieve for such lateral sifting movement in an endless, looped pathapproaching,

but not materially more than, about two inches.

throw, and means for moving said sieve through said path at a speed in the range from about 290 R. P. M.-;,to about 310 RP. M.

13. In the sifting of material deposited on an approximately horizontally and laterally moving sieve that is disposed to receive, support and sift material deposited thereon, that improvement in the method of operation thereof which comprises moving said sieve laterally in an endless, looped path approaching but not materially exceeding two inches across, and at a speed in the range of approximately 290 R. P. M. to 310 R. P. M.

14. In the sifting of material deposited on a laterally and approximately horizontally moving sieve that is disposed to receive, support and sift material deposited thereon, and that has carrier flights arranged above the upper face thereof along a side' thereof, that improvement in the 'method of operation thereof which comprises moving said sieve laterally in. an endless, looped path of about two inches across, at a speed in the range of approximately 290 R. P. M. to 310 R. P. M.

15. A sifter having a sieve housing containing a sieve upon which material to be sifted is de-- posited, means for yieldingly supporting said sieve for approximately horizontal movement in an approximately circular path, means for imparting to said sieve, in asubstantially horizontal plane, motion in said approximately circular path approaching, but not materially greater than,; approximately -two inches across, and means for driving said motion imparting means at a speed in the range of approximately 290 R. P. M. to 310 R. P. M.

16. A sifter having a sieve housing containing 'a sieve 'upon'whlch material to be sifted is deposited, 'means for yieldingly] supporting said sieve for movement in a substantially circular path, means for imparting to said sieve motion in a. plane approximately parallel to said sieve, and means for driving said motion imparting means at a speed in the range of approximately 300 R. P. M.

imparting motion in a substantially horizontal plane to said sleve housing at a speed of approximately 300 R. P. M., and in-a closed loop path of a radius approaching but not materially exceeding one inch, and means for supporting said housing to permit both rotary motion thereof and a limited movement in an up and down direction.

THOMAS G. CECKA.

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