US3313494A - Suction-type grinding mill - Google Patents

Description

Aprifl M1, NW H. PETERSON 3,313,494

SUCTION-TYPE GRINDING MILL Filed April '7, 1965 4 Sheets-Sheet 1 F 4- 2 32 INVENTOR.

Carl fiPeferson ATTORNEYS Q H- PETERSON SUCTION-TYPE GRINDING MILL 4 Sheets-Sheet 2 Filed April '7, 1965 INVENTOR.

Carl H. Pefersan ATTORNEYS p W67 c. H. PETERSON 3,313,494

l SUCTION-TYPE GRINDING MILL Filed April 7, 1965 4 Sheecs-Sheet a INVENTOR. Carl H. Pe ferson ATTORNEYS m 9 W57 c. H. PETERSON SUCTION-TYPE GRINDING MILL 4 Sheets-Sheet 4 Filed April '7, 1965 INVENTOR. Ca r/ H. Pe Te rson United States Patent 3,313,494 SUCTION-TYPE GRINDING MILL Carl H. Peterson, Denver, (3010., assignor to Charles F. Shepherd, Denver, Colo. Filed Apr. 7, 1965, Ser. No. 446,295 6 Claims. (Cl. 241-56) This invention relates generally to grinding mills and more particularly to improvements in grinding mills of the suction type.

Grinding mills of the suction type generally include a grinding chamber into which coarse materials are introduced for a size reduction and a discharge chamber which draws the ground finer sizes from the grinding chamber. In both chambers there is provided a rotor supporting spaced blades which move at high speeds in proximity to the inner walls of the respective chambers generating centrifugal air movement therein.

In the grinding chamber the impact of the rotor blades with the feed material causes some size reduction but a major portion of the size reduction results from the attrition of the particles as the centrifugal force of the rotor blades crowds the material against the inner surface of the chamber Walls. This centrifugal action in the grinding chamber causes the coarser sizes to remain on the outer periphery and the finer sizes to be displaced toward the center. The fan blades in the discharge chamber draw these finer sizes into the discharge chamber and eject these finer sizes through a discharge outlet in the discharge chamber.

Substantial improvement in the grinding action of a suction-type grinding mill has been attained by improving the action in various portions of this mill. Accordingly, it is the general object of my invention to provide a more effective suction-type grinding mill.

It is an object of my invention to provide a simple, durable and efiicient suction-type grinding mill having an improved arrangement for introducing feed to the grinding chamber.

Another object of my invention is to provide a simple, durable and efficient suction-type grinding mill having a novel blade arrangement on the rotor in the grinding chamber which produces improved grinding in the grinding chamber.

It is another object of my invention to provide a simple, durable and efiicient suction-type grinding mill having a novel arrangement of rotor blades and chamber shaping providing improvements in the discharge action of the discharge chamber.

A further object of my invention is to provide in a suction-type grinding mill an improved control of the discharge from the grinding chamber to the discharge chamber of the mill.

Further objects and advantages of this invention will become apparent as the following description proceeds and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In the drawings:

FIG. 1 is a sectional view of a grinding mill embodying my invention;

FIG. 2 is a sectional view of the grinding mill shown in FIG. 1 taken along line 22;

FIG. 3 is a side elevation view of the drive motor and motor support for the grinding mill shown in FIG. 1;

FIG. 4 is a partial sectional view of the grinding mill shown in FIG. 1 taken along line 44, FIG. 1, showing the flow control between chambers;

FIG. 5 is a partial sectional View of the flow control shown in FIG. 4 taken along line 5-5 showing particularly the external control rod;

FIG. 6 is a perspective view of the plate and arm control portion of the flow control assembly shown in separated relationship;

FIG. 7 is a sectional view of the grinding mill shown in FIG. 1 taken along line 77 showing the interior of the discharge chamber;

FIG. 8 is a rear elevation view of the fan blade; and

FIG. 9 is a side elevation view of the fan blades shown in FIG. 8.

Referring now to the drawings, in FIGS. 1 through 9, the grinding mill is illustrated in detail. The grinding mill includes a sectional casing or housing 2 having a base portion 3 for its support in an upright position, and including a cylindrical upper portion. Another portion adjoining the cylindrical portion functions as a fan housing 4 attached to the housing 2 at the rearward end and an end cover 5 is attached to the housing at the forward or drive end. Housing 2 has its interior surface lined with a suitable liner 2a and fan housing 4 has its interior surface lined with a suitable liner 4a. Housing 1 generally encloses what will hereafter be referred to as the grinding chamber 7 and fan housing 4 generally encloses what will hereinafter be referred to as a discharge chamber 8. Fan housing 4 has a discharge spout for discharging ground material from the discharge chamber 8.

A feed inlet or intake spout 19 extends downwartfly and inwardly through the upper portion of cover 5 to the upper interior of the grinding chamber 7 to direct a gravitational feed of material into the bottom of the grinding chamber. A cover plate 11 is fastened over the outer end of fan housing 4 to close the discharge chamber 8 and provide easy access to the interior thereof.

A horizontally dispose-d shaft 12 extends through the chambers and is supported for rotation at opposite ends of the housing by a bearing housing 13 and bearing 14 fastened to the cover plate 11 at the rearward end and a bearing housing 16 and bearing 17 fastened to the end cover 5 at the forward end. Shaft 12 terminates at the rearward end in the bearing 14 and extends through the bearing 17 at the forward end at 12a for coupling to a drive motor in a manner described more fully hereinafter. A hearing 18 is fitted in cover 5 intermediate the ends of the housing for additional support of shaft 12 during rotation. A hub 29 is afiixed to the shaft 12 Within chamber 7 by a key providing conjoint rotation with the shaft.

A disk-like plate 21 having a hollow central portion fits over the hub 26 and in a notched portion thereof. The attachment of plate 21 to hub 20, its peripheral structure, and components attached thereto are more clearly shown in FIG. 2. Plate 21 is removably attached to the hub by a plurality of connectors disposed in spaced circumferential relation which extend through apertures on the inner surface of the plate. The outer peripheral sides and end of plate 21 support a plurality of blades 22 which are circum ferentially spaced at about angles. Each blade 22 has a central slotted portion which extends a substantial distance over the end and along sides of .plate 21. In section, each blade 22 includes a base surface portion 23 and an adjoining inclined surface portion 24 which is inclined forwardly in the direction of rotation of the plate 22. Surface portions 23 and 24 provide scoop-like structure to aid in moving the material in a circular path in chamber 7 in a manner described more fully hereinafter.

Elongated rod members 25 project from plate 21 and provide a seat for each surface portion 23. A pair of fasteners, such as bolts, one on each side of plate 21 extend through member 25 and base portion 23 to detachably fasten each blade 22 to plate 21 for conjoint rotation therewith.

Plate 21 inwardly of blades 17 has a plurality of apertures 27 which are circumferentially spaced at about 45 angles. Apertures 27 are disposed on plate 21 so as to provide a substantially alined passage for air and material flow between the inlet it) and outlet of chamber 7. The general shape of blade 2 corresponds to that of the inner walls of chamber 7 and there is substantial spacing therebetween for movement of the material being reduced in size. The lower portion of housing 2 above the base portion 3 is provided with access openings into the lower portion of chamber 7 which are normally closed by side cover plates 28 on each side of the housing and which are detachably fastened to housing 2.

The grinding mill is powered by a drive motor 3t) detachably mounted on a base 31 as shown in FIG. 3. Base 31 is connected to the base portion 3 through a base extension 32 the width of which will vary to ac commodate different shaft lengths of different motor ratings. Base 3 and motor base 31 will preferably be secured on the same fiat supporting surface. A flexible coupling 33 is provided between the motor shaft and the shaft extension 12a of the mill shaft. This drive arrangement allow easy substitution of drive motors for the grinding mill and permits the customer to furnish his own motor.

A flow control is provided between chambers 7 and 8 and generally includes a stationary regulator plate 35 attached to housing 2 and a movable regulator plate 36. The component structure detail and arrangement of this control is more fully illustrated in FIGS. 4 through 6. Plate 35 includes a substantially flat outer portion 37, an inwardly sloping intermediate portion 38 and a fiat inner portion 39 disposed at right angles to the shaft. Inner portion 39 has a central aperture for fitting over hub in close fitting relationship and has a plurality of spaced radially extending slots 49 which provide a passage between chambers 7 and 8.

Movable regulator plate 36 is generally fiat and circular and is disposed in juxtaposed relation on the upstream side of inner portion 39. Plate 36 i similar in shape to inner portion 39 having a central aperture for fitting over hub 20 in close fitting relationship and a plurality of similarly shaped, spaced, radially-extending slots 42. Plate 36 so disposed is rotatable with respect to portion 39 and will vary the passage through slots 40 from a fully open to a fully closed position.

Rotation of plate 36 is made through a mechanical control which includes an inner arm 44 directly attached to plate having a gear mesh coupling with an outer arm 45 directly connected to an exterior control. Arms 44 and 45 are disposed on one side of the mill housing and are shaped to extend parallel with the side of regulator plate 35 on the discharge chamber side. The adjoining ends of arms 44 and 45 having meshing teeth 46 so that rotational movement of arm 45 will rotate arm 44. An external connecting rod 48 extends through an aperture in and is fastened to the outer end of arm 45 for selective rotation on the side of housing 2. A control rod 49 is attached to the extended end of connecting rod 48 for rotating rod 48 in either direction. Thus, rotation of control rod 43 in either direction from the exterior of housing 2 will rotate movable plate 36 in either direction through arms 44 and 45 and rod 48. The passage through the slots 43 in the stationary plate varies from a fully open to a fully closed position and by varying the passage through slots the grinding size may be regulated. This regulation usually will be performed at the beginning of the grinding operation and provides a wide range of grinding sizes for the operators selection.

A hub 51 mounted on a sleeve 52 is fitted over shaft 12 in chamber 8 and is fastened to the rearward end of hub 20 for conjoint rotation therewith. Hub 51 has six equally spaced, radial arms 53. Each said arm has a fan blade 54 attached thereto. An annulus 55 fastens 4 on the side of each radial arm 53 in a notched portion of each blade for additional support of the blades during high speed rotation.

The shape of the interior of the fan housing 4 which defines discharge chamber 8 and the details of the fan blades are shown in FIGS. 7 through 9. Discharge chamber 8 is generally volute in section with shaft 12 offset from the center. With this arrangement the fan blades 54 are progressively distant from the inner wall of the chamber 8 as shown when rotated from the inner end of the discharge outlet 9 to the outer end of the discharge outlet.

Each blade 54 has an outer end portion 57 which is generally rectangular in shape and fits in close proximity to the chamber walls. The inner end portion 58 is tapered on the outer side. A pair of apertures 59 are provided adjoining the taper for attaching the blade to the hub. In section, the blade narrows inwardly on both the outer portion and the inner portions on the forward side; the forward side being the forward face with reference to the direction of rotation which is shown by the directional arrow as being in the clockwise direction. On the rearward side the upper portion has a generally rectangular recess 61 and a generally triangular recess 62 intermediate the blade ends. This particular shaping of the blade and disposition with respect to the chamber walls increases the centrifugal action in the discharge chamber and imparts a lateral component of force to the air so as to increase the suction action and more effectively discharge the suspended ground material from the grinding chamber.

In operation of the mill previously described, a coarse material is fed into intake spout 10 which provides a gravitational feed inlet to the upper portion of the grinding chamber 7 and also supplies the air to the chambers. The feed material falls to the bottom of the grinding chamber until entrained in the centrifugal circulation. Grinding blades 22 rotating at high speed impinge on and scoop up the circulating solids which are entrained in the circulating air flow and are thrown against the walls of the chamber. The impact of the blades 22 and the chamber wall causes some size reduction but a major portion of the reduction results from the attrition action of the particles as the blades crowd the material against the side of the chamber walls and circulate it in the centrifugal flow.

In this eentrifu gal action the coarser sizes tend to remain at the outer periphery and the finer sizes are drawn toward the center of the chamber. Circulating air and airborne material pass around the periphery of the blades 22 and progress laterally through apertures 27. These apertures provide a substantially direct flow path for the entering air supply inducing flow of a substantial amount of air from the inlet to the outlet of the grinding chamber in which the circulating airborne solids will be entrained while oversize remains in the grinding chamber until reduced to a size which will become airborne.

The fan blades 54 rotating at high speed in the discharge chamber are longer and develop a higher peripheral speed than the blades in grinding chamber 7 thereby inducing flow which draws the finished product circulating in the central portion of the grinding chamber 7 through the passages of slots 40 and 42 and eject this product directly through discharge outlet 9. Rotation of the movable plate 36 by control rod 49 will change the rate of discharge of the finished product and thereby vary the size of the product discharge from the grinding chamber.

While the apparatus herein described constitutes the preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus and changes may be made without departing from the scope of the invention which is defined in the appended claims.

I claim:

1. In a grinding mill for reducing a material from a coarser size to a finer size, an upright housing having its interior divided into a grinding chamber and a discharge chamber, said housing having an upper feed inlet for gravitational movement of feed material to the bottom of the grinding chamber and an upper outlet in its discharge chamber, a horizontally disposed shaft extending through the housing and having a portion extending beyond the housing at one end, a rotor mounted on the shaft in the grinding chamber and including a hub portion, a disk-like connector member mounted on the hub for conjoint rotation therewith, said connector having a circumferentiallyspaced series of apertures and blade members carried outwardly of said openings with the outer edges of the blade members distant from the peripheral wall of the grinding chamber, said blade members being shaped to provide a scoop portion on their forward surfaces for imparting centrifugal movement to material in the grinding chamber, a stationary plate and a movable plate disposed in juxtaposed relation in a passage between the grinding chamber and the discharge chamber, said plates having a circumferential arrangement of radially extending slots in general alinement, the movable plate being rotatable to vary the alinement of its slots with the slots of the stationary plate from a fully open to a fully closed relation for controlling the rate of discharge from the grinding chamber, a fan member mounted on the shaft within the discharge chamber and having radially-extending blades inclusive of scoop portions for airborne discharge of finely divided product through the upper outlet, and means exteriorly of the housing for rotating said shaft.

2. In a grinding mill for reducing material from a coarser size to a finer size, an upright housing having its interior divided into a grinding chamber and a discharge chamber, said housing having an upper feed inlet for gravitational movement of feed material to the bottom of the grinding chamber and an upper outlet in its discharge chamber, a horizontally disposed shaft extending through the housing and having a portion extending beyond the housing at one end, a rotor mounted on the shaft in the grinding chamber and including a hub portion, a disk-like connector member mounted on the hub for conjoint rotation therewith, said connector having a circumferentially-spaced series of apertures and blade members carried outwardly of said openings with the outer edges of the blade members distant from the peripheral wall of the grinding chamber, said blade members being shaped to provide a scoop portion on their forward surfaces for imparting centrifugal movement to material in the grinding chamber, a stationary plate and a movable plate disposed in juxtaposed relation in a passage between the grinding chamber and the discharge chamber, said plates having a circumferential arrangement of radially extending slots in general alinement, the movable plate being rotatable to vary the alinement of its slots with the slots of the stationary plate from a fully open to a fully closed relation for controlling the rate of discharge from the grinding chamber, a fan member mounted on the shaft within the discharge chamber and having radially-extending blades inclusive of scoop portions for airborne discharge of finely divided product through the upper outlet, means exteriorly of the housing for rotating said shaft, and means exteriorly of the housing for rotating said movable plate to vary the size of product passing to the discharge chamber from the grinding chamber.

3. In a grinding mill for reducing a material from a coarser size to a finer size, an upright housing having its interior divided into a grinding chamber and a discharge chamber, said housing having an upper feed inlet for gravitational movement of feed material to the bottom of the grinding chamber and an upper outlet in its discharge chamber, a horizontally disposed shaft extending through the housing and having a portion extending beyond the housing at one end, a rotor mounted on the shaft in the grinding chamber and including a hub portion, a disk-like connector member mounted on the hub for conjoint rotation therewith, said connector having a circumferentially-spaced series of apertures and blade members carried outwardly of said openings with the outer edges of the blade members distant from the peripheral wall of the grinding chamber, said blade members being shaped to provide a scoop portion on their forward surfaces for imparting centrifugal movement to material in the grinding chamber, a stationary plate and a movable plate disposed in juxtaposed relation in a passage between the grinding chamber and the discharge chamber, said plates having a circumferential arrangement of radially extending slots in general alinement, the connector apertures and plate slots being in substantial alinement with the feed inlet into the chamber to provide a substantially horizontal flow path between the inlet and outlet of said grinding chamber, the movable plate being rotatable to vary the alinement of its slots with the slots of the stationary plate from a fully open to a fully closed relation for controlling the rate of discharge from the grinding chamber, a fan member mounted on the shaft within the discharge chamber and having radially-extending blades inclusive of scoop portions for airborne discharge of finely divided product through the upper outlet, and means exteriorly of the housing for rotating said shaft.

4. In a grinding mill for reducing a material from a coarser size to a finer size, an upright housing having its interior divided into a grinding chamber and a discharge chamber, said housing having an upper feed inlet for gravitational movement of feed material to the bottom of the grinding chamber and an upper outlet in its discharge chamber, a horizontally disposed shaft extending through the housing and having a portion extending beyond the housing at one end, a rotor mounted on the shaft in the grinding chamber and including a hub portion, a disk-like connector member mounted on the hub for conjoint rotation therewith, said connector having a circumferentiallyspaced series of apertures and blade members carried outwardly of said openings with the outer edges of the blade members distant from the peripheral wall of the grinding chamber, said blade members being shaped to provide a scoop portion on their forward surfaces for imparting centrifugal movement to material in the grinding chamber, a stationary plate and a movable plate disposed in juxtaposed relation in a passage between the grinding chamber and the discharge chamber, said stationary plate having a fiat outer portion attached to the housing, an inwardly extending intermediate portion and a flat inner portion, said inner portion and the movable plate having an aperture surrounding the hub portion and a circumferential arrangement of radially extending slots in general alinement, and the movable plate being rotatable to vary the alinement of its slots with the slots of the stationary plate from a fully open to a fully closed relation for controlling the rate of discharge from the grinding chamber, a fan member mounted on the shaft within the discharge chamber and having radially-extending blades inclusive of scoop portions in their forward surfaces for airborne discharge of finely divided product through the upper outlet, and means exteriorly of the housing for rotating said shaft.

5. In a grinding mill for reducing a material from a coarser size to a finer size, an upright housing having its interior divided into a grinding chamber and a discharge chamber, said housing having an upper feed inlet for gravitational movement of feed material to the bottom of the grinding chamber and an upper outlet in its discharge chamber, the discharge chamber being generally volute in sect-ion, a horizontally disposed shaft extending through the housing in offset relation to said discharge chamber and having a portion extending beyond the housing at one end, a rotor mounted on the shaft in the grinding chamber and including a hub portion, a disk-like connector member mounted on the hub for conjoint rotation therewith, said connector having a circumferentiallyspaced series of apertures and blade members carried outwardly of said openings with the outer edges of the blade members distant from the peripheral wall of the grinding chamber, said blade members being shaped to provide a scoop portion on their forward surfaces for imparting centrifugal movement to material in the grindingg chamber, a stationary plate and a movable plate disposed in juxtaposed relation in a passage between the grinding chamber and the discharge chamber, said plates having a circumferential arrangement of radially extending slots in general alinement, the movable plate being rotatable to vary the alinement of its slots with the slots of the stationary plate from a fully open to a fully closed relation for controlling the rate of discharge from the grinding chamber, a fan member mounted on the shaft within the discharge chamber and having radially-extending blades inclusive of scoop portions for airborne discharge of finely divided product through the upper outlet, and means exteriorly of the housing for rotating said shaft.

6. In a grinding mill for reducing a material from a coarser size to a finer size, an upright housing having its interior divided into a grinding chamber and a discharge chamber, said housing having an upper feed inlet for gravitational movement of feed material to the bottom of the grinding chamber and an upper outlet in its discharge chamber, a horizontally disposed shaft extending through the housing and having a portion extending beyond the housing at one end, a rotor mounted on the shaft in the grinding chamber and including a hub portion, a disk-like connector member mounted on the hub for conjoint rotation therewith, said connector having a circumferentially-spaced series of apertures and blade members carried outwardly of said openings with the outer edges of the blade members distant from the peripheral wall of the grinding chamber, said blade members being shaped to provide a scoop portion on their forward surfaces for imparting centrifugal movement to material in the grinding chamber, a stationary plate and a movable plate disposed in juxtaposed relation in a passage between the grinding chamber and the discharge chamber, said plates having a circumferential arrangement of radially extending slots in general alinement, the movable plate being rotatable to vary the alinement of its slots with the slots of the stationary plate from a fully open to a fully closed relation for controlling the rate of discharge from the grinding chamber, a fan member mounted on the shaft within the discharge chamber and having radially-extending blades, each of said blades having an outer end portion of generally rectangular shape in close proximity to the chamber walls and a tapered inner end portion, the forward surface being tapered on the outer and inner end portions and the rearward surface having recess portions for airborne discharge of finely divided product through the upper outlet, and means exteriorly of the housing for rotating said shaft.

References Cited by the Examiner UNITED STATES PATENTS 448,844 3/1891 Burnham 24l54 X 795,133 7/1905 Johnson 241-56 1,621,571 3/1927 Witz 241-59 X 1,748,050 2/1930 Harrington c 241-56 1,765,309 6/1930 ONeill 24156 3,037,712 6/1962 Hoshokawa 24l56 WILLIAM W. DYER, 1a., Primary Examiner.

H. F. PEPPER, Assistant Examiner.

Claims (1)

1. IN A GRINDING MILL FOR REDUCING A MATERIAL FROM A COARSER SIZE TO A FINER SIZE, AN UPRIGHT HOUSING HAVING ITS INTERIOR DIVIDED INTO A GRINDING CHAMBER AND A DISCHARGE CHAMBER, SAID HOUSING HAVING AN UPPER FEED INLET FOR GRAVITATIONAL MOVEMENT OF FEED MATERIAL TO THE BOTTOM OF THE GRINDING CHAMBER AND AN UPPER OUTLET IN ITS DISCHARGE CHAMBER, A HORIZONTALLY DISPOSED SHAFT EXTENDING THROUGH THE HOUSING AND HAVING A PORTION EXTENDING BEYOND THE HOUSING AT ONE END, A ROTOR MOUNTED ON THE SHAFT IN THE GRINDING CHAMBER AND INCLUDING A HUB PORTION, A DISK-LIKE CONNECTOR MEMBER MOUNTED ON THE HUB FOR CONJOINT ROTATION THEREWITH, SAID CONNECTOR HAVING A CIRCUMFERENTIALLYSPACED SERIES OF APERTURES AND BLADE MEMBERS CARRIED OUTWARDLY OF SAID OPENINGS WITH THE OUTER EDGES OF THE BLADE MEMBERS DISTANT FROM THE PERIPHERAL WALL OF THE GRINDING CHAMBER, SAID BLADE MEMBERS BEING SHAPED TO PROVIDE A SCOOP PORTION ON THEIR FORWARD SURFACES FOR IMPARTING CENTRIFUGAL MOVEMENT TO MATERIAL IN THE GRINDING CHAMBER, A STATIONARY PLATE AND A MOVABLE PLATE DISPOSED IN JUXTAPOSED RELATION IN A PASSAGE BETWEEN THE GRINDING CHAM-

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