US3389862A - Screen mill - Google Patents

Description

June 25, 1968 H. o. SCHUTTE SCREEN MILL 2 Sheets-Sheet 1 Filed May 17, 1965 INVENTOR BY HERMAN o. SCHUTTE ATTORNEYS June 25, 1968 H. D. SCHUTTE SCREEN MILL Filed May 17, 1965 2 Sheets-Sheet 2 l N VENTOR.

HERMAN'D. SCHUTTE United States Patent 3,389,862 SCREEN MILL Herman D. Schutte, 51 Woodbury Drive,

Snyder, N.Y. 14226 1 Filed May 17, 1965, Ser. No. 456,294 3 Claims. (Cl. 241-86) ABSTRACT OF THE DISCLOSURE A screening mill consisting of a housing into which a rotor shaft extends having a plurality of hammers pivotally carried thereon describing a cylindrically shaped hammer tip path plane concentric to said rotor shaft within said housing, a material sizing screen of spiral-shaped profile mounted interiorly of said housing in substantially concentric relation to said tip plane path and comprising a perforated plate bent into a spiraloid form with its opposite ends disposed in spaced-apart relation and thereby defining a material inlet opening through a top portion of said screen into the interior thereof, and amaterial feed chute leading through an apertured top portion of said housing and delivering mill feed through said inlet opening into the interior of said screen and on top of said hammers.

This invention relates to screen mills as in the case of US. Patents No. 2,328,170 and 2,532,262; and more particularly to further improved means for screen arrangernents therein.

A primary object of the present invention is to provide a pulverizer of the hammer mill type having an improved mill feed and product sizing screen arrangement.

Another object of the invention is to provide a mill of the character described having an improved form of mill feeding and product screening arrangement where the screen element is adapted to be mounted and demounted with respect to the mill casing in an improved manner.

Another object of the invention is to provide in a mill of the character described improved means for detachably locking the product screening member in operative position relative to the mill frame.

Other objects and advantages of the invention will appear in the specification hereinafter.

In the drawing:

FIG. 1 is a side elevation of a hammer mill of the invention showing by broken lines the screen member thereof in mounted position;

FIG. 2 is a right hand end elevational view of the machine of FIG. 1, with a portion of the mill casing broken away to show the interior thereof;

FIGS. 3, 4, are sectional views taken as suggested by lines 33 and 4-4, respectively, of FIG. 2; and

FIG. 5 is an inside perspective view of a screen holding component of the machine of the invention.

The drawings illustrate the invention by way of example in connection with a hammer mill of the type that is adapted particularly for grinding or pulverizing grain or other commodities; and as shown herein the mill comprises essentially a base carrying bearing blocks 12 for rotatably supporting the rotor shaft 14. The rotors 16 are carried by the shaft 14 and in turn each mounts a series of hammers 18 which are pivotally connected to the rotors so as to revolve in radially extended relation therefrom. Heads may be carried by the hammers 18 if desired by means of the connection apertures 20, to receive the majority of the wear in connection with processing of the mill feed. The mill casing is of modified rectangular form, and is fabricated of sheet metal to atented June 25, 1968 ice P comprise a back plate 22 and a horseshoe-shaped peripheral end and top cover portion 24. At the lower corner end portions of the casing, relatively short bottom plates 26, 26, are provided and the structure is braced by means of diagonally disposed baffle plates 28 welded to the adjacent end plate and bottom plate parts (FIGS. 3, 4). Thus, a discharge opening 30 for the screened product of the mill is provided at the center base portion of the casing. The mill feed supply device may be of any suitable form, but as illustrated herein includes a generally standard type gravity feed hopper designated 32. A vertically adjustable slide plate 34 which is manualy movable as by means of a control arm 35 may be employed to variably throttle the size of the outlet opening into the mill casing.

Whereas in some prior type mill constructions provision is made for delivery of the mill feed material through a window in a side wall portion of the casing, the mill feed material is thereby directed to fall primarily against the hammers at that side of the mill. This is disadvantageous because some of the rotors will flood with feed material, while others rotate idly. Hence, the mill operation is not efficient. Also, in this case some of the rotors and rotor hammers are subjected to excessive wear, and the maintenance and repair problems are most trouble-some. On the other hand, it is a particular feature of the present invention that the mill feed delivers into the top of the mill casing in the form of a stream spread uniformly transversely of the entire inside width of the mill casing, as best shown in FIG. 2. By virtue of this arrangement the incoming mill feed material is delivered by gravity to fall directly on top of all of the hammers of the mill, in evenly distributed manner thereover.

To accommodate this advantageous full width mill feed system while at the same time obtaining the advantages of a substantially 360 degrees screening area, I provide a spiraloid-shaped screen as indicated at said screen having a short gap in the periphery thereof through which the mill feed material passes to the interior of the screen. Hence, the screen may be formed into a generally cylindrical form and slip-fitted at one of its side edges into a grooved track device 42 which is embodied in the inner side wall portion of the casing back plate 22. The track 42 is shaped as shown in FIG. 3 to encircle the tip paths of the rotor hammers as the mill operates, while avoiding interference with inlet delivery of the mill feed material. For this purpose the feed hopper is formed with a delivery spout portion 44 (FIG. 3) which discharges the feed material as shown into the interior of the screen 40 and into the zone of hammer rotation uniformly across the entire Width of the mill interior. Thus the hammers pick up the mill feed material and pound it against the inside of the screen 40 until such time as it passes through the screen and then falls down and out of the mill through the bottom opening, as illustrated by the flow directional arrows in FIG. 3. Note that the spiral shaped screen member 40 includes an elfective screening length of the order of a full 360 circle screen.

To close the other side of the screen 40, a closure plate 46 may be employed as best shown in FIG. 5, which is shaped to complement the peripheral configuration of the screen 40. The plate 46 includes ledge devices as indicated at 48, thereby providing a grooved track into which the outer edge of the screen slip-fits. The plate 46 preferably includes an upstanding hanger portion 50 which is perforated as indicated at 52 so that the plate 46 may be hung by means of a pin 54 upon a depending bracket portion 56 extending fro-m the mill casing. Thus, the closure plate 46 is guided to stand in proper operative position to close the outer side of the cylindrical screen 40.

To hold the closure plate 46 in operative position and to simultaneously seal the mill casing against escape of material, a casing door designated 60 is swung as by means of hinges 62 relative to the casing structure, and door holding clamps as indicated at 64, 64, are provided to cam-lock the door in tightly sealed relation on the casing. The door 69 is radially ribbed as indicated at 66 to stiffen the door structure, and machine screws 68 are threaded through the door to bear at their inner ends against the closure plate 46 whenever the door 60 is in closed, locked position. Thus, from externally of the door the hand screws 68 may be turned down so as to firmly press the closure plate against the edge of the screen, thereby insuring its maintenance in operative position.

I claim:

1. In a screening mill, in combination,

a housing having opposite side walls and a cover extending between said side walls,

a horizontally disposed rotor shaft projecting into said housing through one of said side walls,

a plurality of hammers pivotally carried by said rotor shaft within said housing and describing a cylindrically shaped hammer tip plane path concentrically of said rotor shaft when rotating therewith,

a material sizing screen of spiral-shaped profile and extending between said side walls, said screen being perforate throughout and being spaced throughout from said cover, the opposite ends of said screen being disposed in substantially horizontally spacedapart relation to define an upwardly facing material inlet opening through the top portion of the screen into the interior thereof,

a material feed chute extending through said cover at the top of said housing and leading to said mate- 4-, rial inlet opening to deliver material into the region bounded by said screen and said side walls and on top of said hammers, one end of said screen, at one side of said inlet opening, being closely adjacent said tip plane path and the opposite end of thevscrcen being distantly spaced therefrom, a

and said rotor shaft being rotated in that direction causing said hammers to pass from said opposite end of the screen and along the length of the screen in approaching said one end of the screen.

2. In the screening mill as defined in claim 1 wherein said side walls are provided with ledge means receiving the opposite side edges of said screen in slip-fitted relation.

3. In the screening mill according to claim 2 wherein the other of said side walls is mounted for movement toward and away from said screen.

References Cited UNITED STATES PATENTS Re. 21,523 8/1940 Elderkin 24186 1,786,262 12/1931) Poppelman 24 l86 1,911,718 5/1933 Saunders 24186 2,253,087 8/1941 Neal 241-88 3,169,711 2/1965 Helms 241--9) FOREIGN PATENTS 583,515 12/1946 Great Britain.

ANDREW R. JUHASZ, Primary Examiner.

WILLIAM W. DYER, JR., Examiner.

R. J. ZLATNIK, Assistant Examiner.

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