US3218038A

US3218038A - Rotary blender and polisher

Info

Publication number: US3218038A
Application number: US224348A
Authority: US
Inventors: William H Chadbourne; Roy W Viehe
Original assignee: FIBERFIL Inc
Current assignee: FIBERFIL Inc
Priority date: 1962-09-18
Filing date: 1962-09-18
Publication date: 1965-11-16
Anticipated expiration: 1982-11-16
Also published as: FR1387848A; NL297717A; GB1043847A

Description

Nov. 16, 1965 w, CHADBOURNE ETAL 3,218,038

ROTARY BLENDER AND PQLISHER Filed Sept. 18, 1962 2 Sheets-Sheet 2 INVENTORS. WILLIAM H. C'unoaouem;

BY Roy W. VIEHE ATro/IveYs.

nitecl States Patent 3,218,038 ROTARY BLENDER AND POLISHER William H. Chadbourne, North Webster, and Roy W. Vielle, West Lafayette, Ind., assignors to Fiberfil, Inc., Warsaw, Ind., a corporation of Indiana Filed Sept. 18, 1962, Ser. No. 224,348 15 Claims. (Cl. 2593) This invention relates to blenders, or machines designed for use in the dry mixing of particled materials and in the tumble-polishing of pelletized materials or the like. Such machines embody a hollow drum mounted for rotation about a generally horizontal axis and often provided interiorly with flights which lift and drop the material as the drum is rotated. Blenders are of two general typesnamely, those used for treatment of material in batches and those used for the continuous treatment of material. Our invention is concerned especially with blenders of the latter type.

Two factors which influence the design of a continuous drum-type blender, are the distance over which it is desired that the material fall upon release from the flights and the residence time of the material within the blender, the former factor determining the diameter of the blender and the latter its length. Provision for both the desired distance of fall and residence time frequently results in blenders so large and heavy that the rotating drum must be supported on rollers and driven by means of high power output.

It is the primary object of our invention to provide a continuous blender in which the residence time will be independent of the axial length of the rotating drum and can be accurately controlled. A further object of the invention is to provide a blender which can be quickly emptied and easily cleaned.

In carrying out our invention We employ a drum having a diameter such as is required to provide the desired distance of fall and a relatively short axial extent. This drum is rigidly mounted on a hollow shaft supported for rotation on an axis having a slight inclination to the horizontal and is divided into two compartments by a medial partition perpendicular to the axis. Slots in the wall of the hollow shaft provide communication between the interior of the shaft and each compartment, while the two compartments are interconnected by an opening in the partition. Each compartment is provided with a circumferential series of flights which elevate and drop the material being treated as the drum rotates, such flights being so designed that each elevates material to a point Well above the axis before discharging it. Material fed into the higher end of the shaft passes therealong and emerges through a slot in the shaft wall into the first compartment, where it is tumbled by the flights therein. When material builds up in the first compartment to a depth sufiicient to overlap the opening in the partition, it escapes gradually through that-opening into the second compartment, where it is further tumbled. The second compartment is provided with a chute positioned and designed to receive a small proportion of the material falling from the flights and guide it into the hollow shaft to be discharged. If desired, the shaft may be provided with a plurality of axially spaced similar drums through which the material successively passes before being discharged from the lower end of the shaft.

For the purpose of emptying the blender, the aforesaid chute extends to the peripheral wall of the drum where it has a width substantially equal to the axial extent of the second compartment, and the first compartment is provided with a chute of similar shape and disposition. The inner portion of the chute of the first compartment is covered and arranged to discharge, not directly into the 3,218,038 Patented Nov. 16, 1965 ice shaft, but into the other chute through an opening in the partition which separates the two compartments. When the drum is rotated in a direction opposite to that of normal operation, the outer ends of the two chutes serves as scoops which pick up the material and guide it into the shaft.

Further objects and features of our invention will become apparent from the following more detailed description and from the accompanying drawings, in which:

FIG. 1 is a side elevation of a blender;

FIG. 2 is an elevational view of one of the blender drums looking in the axial direction of material-flow and with a portion of the drum-wall broken away to show the interior construction;

FIG. 3 is an elevational view similar to FIG. 2 but looking in the opposite direction; and

FIG. 4 is a fragmental section through one of the drums on the line 4-4 of FIG.

Referring to FIG. 1, it will be seen that the blender comprises a frame 10 rotatably supporting a hollow shaft 11 on which three drums 12 are rigidly mounted in axially spaced relation. The shaft has a slight inclination to the horizontal, desirably about 5, its higher end receiving the material to be treated, as through a supply chute 13, and its lower end being open for discharge of the material.

The three drums may be identical in construction, and it will therefore be necessary to describe but one of them. As indicated in FIGS. 2 and 3, each drum is hexagonal in shape, although that particular shape is not essential, and is divided by a medial partition 15 into two compartments designated respectively as 16 and 17 in FIGS. 2, 3, and 4. Of the two compartments in each drum, the compartment 16 is the one nearer the inlet end of the shaft. In each compartment are a series of flights 20 which project inwardly from the peripheral wall 21 of the drum to elevate, and then drop, material as the drum rotates. The end walls of each drum are provided with openings through which access may be had to the interior of the drum, each of such openings having a removable cover 22, which is desirably transparent.

The flights 20 are so inclined relatively to the radial direction that they will elevate material to a height well above the axis of rotation and desirably at least some of them are so disposed that a portion of the material discharged will impinge on the shaft 11.

Within each drum, the hollow shaft 11 is provided with an elongated slot 24 which overlaps both of the

compartments

16 and 17. Midway of the axial extent of such slot, the shaft is provided interiorly with a partition N 25 which is coplanar with the drum-dividing partition 15 and which serves to cause approaching material to pass through the slot 24 into the compartment 16. Material entering the hollow shaft 11 at the inlet end thereof progresses through the shaft until it encounters the partition 25 and passes through the slot into the compartment 16, where it is repeatedly elevated and dropped as the drum rotates. Material fed to the compartment 16 builds up therein until it attains a depth corresponding to the location of an opening 26 provided in the partition 15. Favored by the inclination of the shaft 11, material accumulating in the compartment 16 will escape gradually through the opening 26 into the compartment 17, where it will be repeatedly elevated and dropped by the flights in that compartment. Residence time of the material in the compartment 16 can be controlled by varying the number, size, and radial disposition of the openings 26.

To effect the feeding of material from the compartment 17, that compartment is provided with a discharge chute 30. Such chute, which is fixed in the drum, ex-

tends along the partition from the shaft 11 to the peripheral drum-wall 2t and desirably has (FIG. 3) an inner portion disposed generally radially and an outer portion curving toward the drum wall 21 in a direction opposite to that of normal drum rotation. The chute communicates at its inner end with a slot 2 in the shaft 11 and has an open side presented in a direction opposite to that in which the drum normally rotates. For a purpose which will become apparent hereinafter, the width of the chute fail at the periphery of the drum is substantially equal to the axial extent of the compartment 17; but in order to lessen its tendency to trap and elevate material it desirably decreases in Width toward the drum-axis, as shown in FIG. 4.

If the flights are disposed in the above described desirable manner, some of the material dropping from them will enter the chute 3% while it is still inclined inwardly and downwardly as indicated in FIG. 3, and materials so entering the chute Will flow by gravity through the slot 24 into the interior of the shaft 11 where it impinges on an inclined deflector plate 31 fixed in the shaft at an angle favoring deflection of the material toward the discharge end of the shaft. Material so reintroduced into the shaft feeds therealong into the compartment 16 of the next drum 12 or, in the case of the last drum, through the shaft to the discharge end thereof.

As will be appreciated, the escape of material from the compartment 17 in the manner just described proceeds at a relatively slow rate, since most of the material dropped from the upwardly moving flights Ztl will either escape entry into the chute in falling or will enter the chute when it is inclined outwardly and downardly to direct the material it receives outwardly for re-elevation rather than inwardly for discharge into the shaft. If, as is shown in FIG. 4, the inner end of the chute 39 occupies only a portion of the slot 24 in the shaft a small proportion of falling material may enter the shaft through such slot directly when the slot is directed more or less upwardly. Residence time of the material in the compartment 1'7 is determined largely by the width of the inner portion of the chute 3t and by the extent of each fractional drum revolution during which it is both in a position to receive dropped material and so inclined as to direct the received material inwardly and through the slot 24. For example, if the flights which immediately trail the chute in normal rotation of the drum were narrower or disposed at a smaller angle to the radial directiton, they would drop material earlier, a smaller proportion of the dropped material would be guided into the shaft, and residence time of the material in the compartment 17 would be increased.

The compartment 16 is provided with a chute 34 similar in shape and disposition to the chute 30 but differing therefrom in that its inner portion is provided with a cover 35 and discharges through an opening 36 in the partition 15 either into the chute 30 or into the slot 24 on the opposite side of the shaft-partition 25. See FIG. 4. Conveniently, the opening 36 is a lobe of the otherwise circular shaft-receiving opening of the partition 15 and the obliquely disposed inner end 37 of the side wall of the chute 34 abuts the edge of the partition 25. The cover 35 extends outwardly from the inner end of the chute 34 for a distance great enough to prevent any material dropped by the flights 20 from entering the chute while it is disposed in an inwardly and downwardly sloping direction, and the chute 34 therefore plays no part in normal operation of the blender.

From the foregoing description, it will be apparent that material fed into the inlet end of the shaft progresses therealong, enters the compartment 16 of the drum 12 nearest the inlet end of the shaft 11, is tumbled in that compartment 16, escapes through the opening 26 into the compartment 17 of the first drum, is further tumbled in that compartment, and is discharged therefrom through the hollow shaft 11 into the next drum 12, in

which the tumbling and feeding action is similar to that which occurred in the first drum. Material emerging from the compartment 17 of the last drum 12 passes through the shaft 11 to the end thereof, where it is discharged. If desired, the shaft 11 may be provided interiorly with a helical flight 40 promoting the feeding of material along the shaft.

Ordinarily, a blender is designed to provide a residence time so great that the interval required to empty the blender by continuing it in operation after the feed of material to it has been terminated would be objectionably long. The blender shown and described herein, however, can be emptied quickly merely by reversing its direction of rotation. As will be apparent from FIGS. 2 and 3, rotation of the blender in a direction opposite to that indicated by the arrows causes the outer ends of the

chutes

30 and 34 to act as scoops which pick up the loose material as they rotate through the lower portion of their path of movement and discharge the picked-up material into the hollow shaft 11 as the chutes attain a position in which their inclination is downward and inward. While, in the specific device shown, the material so fed into the shaft from drums other than the last one must pass through one or more additional drums before being discharged from the shaft, the emptying of the blender proceeds very rapidly.

The particular material which the specific blender shown and described was designed to treat is a thermoplastic molding compound in the form of elongated granules or pellets containing longitudinally extending glass fibers. Such material is produced by impregnating and coating continuous lengths of glass strand or roving with a thermoplastic resin in liquid form, curing the resin, and then chopping the strand into pellets or granules of H the desired length. The granules so formed possess sharp edges which would interfer with feeding of the compound in an injection molding machine. Further, since the glass fibers do not all break in the same plane, short lengths of the fibers project from opposite ends of each granule, and such projecting fiber-ends are undesirable. Treatment of the molding compound in the blender described rounds the sharp edges of the granules and breaks off the projecting fiber-ends substantially flush with the ends of the granules. The broken-off fiber ends agglomerate in masses substantially larger than the granules of molding compound and can be separated therefrom by a foraminous screen provided on the discharge end of the shaft 11. The openings in such screen are large enough to permit passage of the granules into a first discharge chute 46 located below the screen but small enough to retain the masses of fiber-ends, which dis charge from the end of the screen 4-5 into a second chute 47.

In a blender for use in removing projecting fiber ends from molding-compound granules, we have found drums seven feet in diameter and one foot in axial extent to be appropriate. A shaft ill formed from a length of fiveinch pipe of one-half inch wall thickness has been found satisfactory to support three such drums, as shown in FIG. 1, with a space of 18 inches between the opposed walls of adjacent drums. It will of course be understood that power-operated means (not shown) will be provided for rotating the blender alternatively in opposite directions.

We claim as our invention:

1. A blender, comprising a hollow shaft having axially spaced inlet and discharge openings, means supporting said shaft for rotation alternatively in first and second opposite directions about a generally horizontal axis, a drum having a peripheral wall and end walls rigidly mounted on said shaft between said inlet and discharge openings, said drum being provided with a partition disposed trans, versely to said axis and dividing the interior of the drum into first and second compartments, said shaft being provided with a first lateral opening through which material fed into said inlet opening may pass into the first compartment and with a second lateral opening through which material from the second compartment may pass into the shaft for flow therethrough toward said discharge opening, said partition having an opening located inwardly from said peripheral wall and through which material may pass from the first compartment into the second compartment, said drum being provided in each compartment with flights which, when the drum rotates in the first direction, repeatedly elevate the material and release it for fall to the bottom of the compartment, first and second discharge chutes located respectively in said first and second compartments and rigid with said drum, both said chutes communicating at their inner ends with said second lateral shaft opening and extending generally outwardly therefrom in their respective compartments to the peripheral drum-wall, that side of said first chute which faces in the second direction of drum rotation being provided with a cover which extends from the inner end of the chute outwardly far enough to prevent entry into the chute of material falling from the flights when the drum is rotating in said first direction, the outer end of said cover being spaced from the peripheral drum-wall to provide an opening through which material can enter the chute when the drum rotates in said second direction, that side of said second chute which faces in the second direction of drum rotation being open for substantially its entire radial extent, the flights in the second compartment being so disposed relatively to the second'chute that some of the material elevated and dropped by such flights when the drum is rotating in said first direction will enter the open side of the chute while the chute is inclined inwardly and downwardly to guide the received material through said second lateral shaft-opening into the interior of the shaft.

2. A blender as set forth in claim 1 with the addition of one or more additional and similar drums rigidly mounted on said shaft in axially spaced relation, the first compartment of each such additional drum receiving material from within the shaft and the second compartment discharging into the shaft through its associated chute.

3. In a blender, a hollow shaft having axially spaced inlet and discharge openings for material to be treated and supported for rotation about a generally horizontal axis, a drum having a peripheral wall and end walls rigidly mounted on said shaft between said openings, said drum being provided with a partition transverse to said axis and dividing the interior of the drum into first and second compartments, said shaft being provided with first and second lateral openings respectively connecting said first compartment with the inlet opening of the shaft and the second compartment with the discharge opening of the shaft, said partition being provided with an opening interconnecting the two compartments and spaced inwardly from said peripheral wall, said drum being provided in both compartments with flights which repeatedly elevate and drop material in the compartments when the drum rotates in one direction, a discharge chute located in said second compartment and rigid with said drum, said chute communicating at its inner end with said second lateral shaft opposing and extending generally radially therefrom, said chute having an open side, said chute and the flights in the second compartment being so disposed and arranged that some of the material elevated and dropped from the flights will enter the chute through the open side thereof while the chute is in an inwardly and downwardly extending position to guide the received material into the second lateral shaft-opening.

4. A blender as set forth in claim 3 with the addition that at least some of said flights in the second compartment are arranged to carry material over the drum axis, the open side of said chute facing opposite to the men tioned direction of drum rotation to receive material so carried over the drum axis.

5. In a blender, ad rum mounted for rotation about a generally horizontal axis and including a blending compartment, means for feeding loose material into said com partment, said drum being provided around the periphery of said compartment with a series of flights which repeatedly elevate and drop material when the drum rotates in one direction, discharge means located near the drum axis for conveying material from the compartment, and a generally radially extending chute mounted in the compartment and rotatable with the drum, said chute being arranged to discharge into said discharge means, said chute having an open side and the chute and flights being so arranged and disposed that some of the material elevated by and dropping from the flights will fall into the chute through the open side thereof while the chute is in an inwardly and downwardly sloping position to guide the received material into said discharge means.

6. A blender as set forth in claim 5 with the addition that at least some of said flights are arranged to carry material over the drum axis, the open side of said chute facing opposite to the mentioned direction of drum rotation to receive material so carried over the drum axis.

7. A blender as set forth in claim 6 with the addition that said chute extends to the periphery of the compartment and has there a width substantially equal to the axial extent of said compartment, the inner portion of said chute having a width less than the axial extent of the compartment.

8. A blender as set forth in claim 6 with the addition that said chute extends to the periphery of the compartment.

9. A blender as set forth in claim 6 with the addition that said chute extends to the periphery of the compartment and has there a width substantially equal to the axial extent of said compartment.

10. In a blender, a drum mounted for rotation about a generally horizontal axis and including a blending compartment having axially space end walls and a pcripheral wall, means for feeding loose material into said compartment, said drum being provided in said compartment with a circumferential series of flights which repeatedly elevate and drop material when the drum rotates in one direction, one of said end walls being provided with an outlet opening spaced inwardly from said peripheral wall, and a generally radially extending chute mounted in said compartment and rotatable with the drum, said chute extending outwardly to said peripheral wall and being there provided with an inlet opening facing opposite to the mentioned direction of drum rotation, said chute having at its inner end an outlet opening discharging exteriorly of the compartment, the radial extent of said inlet opening being so limited that substantially none of the material dropping from the flights in rotation of the drum in the mentioned direction will enter the opening.

11. A blender as set forth in claim 10 with the addition that said inlet opening has, at the peripheral wall, an axial extent substantially equal to that of the compartment, the inner portion of the chute having a width less than the axial extent of the compartment.

12. A blender as set forth in claim 10 with the addition that said inlet opening has, at the peripheral wall, an axial extent substantially equal to that of the compartment.

13. In a blender, a hollow shaft having axially spaced inlet and discharge openings for material to be treated and supported for rotation about a generally horizontal axis, a drum rigidly secured to said shaft between said openings, said drum including a compartment'having axially spaced end walls and a peripheral wall, said shaft being provided with a lateral opening connecting the compartment with the inlet opening of the shaft, said drum being provided in said compartment with a circumferential series of flights which repeatedly elevate and drop material as the drum rotates in one direction,

and a generally radially extending chute mounted in said compartment and rotatable with the drum, said chute extending outwardly to said peripheral Wall and being there provided with an inlet opening facing opposite to the mentioned direction of drum rotation, the radial extent of said inlet opening being so limited that substantially none of the material dropping from the flights in rotation of the drum in the mentioned direction Will enter the opening, said chute being provided at its inner end with an outlet opening through which material entering the inlet opening of the chute is returned to the shaft for flow therethrough toward the discharge opening there- 14. A blender as set forth in claim 13 with the addition that the inlet opening of the chute has, at the peripheral Wall, an axial extent substantially equal to that of the compartment, the inner portion of the chute having a Width less than the axial extent of the compartt ment.

15. A blender as set forth in claim 13 with the addition that the inlet opening of the chute has, at the peripheral wall, an axial extent substantially equal to that of the compartment.

References Cited by the Examiner UNITED STATES PATENTS 2,504,378 4/1950 Bell 259-3 2,638,625 5/1953 Studebaker et al. 259-3 2,797,070 6/1957 Winn et al. 259-3 FOREIGN PATENTS 233,465 4/1961 Australia.

CHARLES A. WILLMUTH, Primary Examiner.

Claims

5. IN A BLENDER, A DRUM MOUNTED FOR ROTATION ABOUT A GENERALLY HORIZONTAL AXIS AND INCLUDING A BLENDING COMPARTMENT, MEANS FOR FEEDING LOOSE MATERIAL INTO SAID COMPARTMENT, SAID DRUM BEING PROVIDED AROUND THE PERIPHERY OF SAID COMPARTMENT WITH A SERIES OF FLIGHT WHICH REPEATEDLY ELEVATE AND DROP MATERIAL WHEN THE DRUM ROTATES IN ONE DIRECTION, DISCHARGE MEANS LOCATED NEAR THE DRUM AXIS FOR CONVEYING MATERIAL FROM THE COMPARTMENT, AND A GENERALLY RADIALLY EXTENDING CHUTE MOUNTED IN THE COMPARTMENT AND ROTATABLE WITH THE DRUM, SAID CHUTE BEING ARRANGED TO DISCHARGE INTO SAID DISCHARGE MEANS, SAID CHUTE HAVING AN OPEN SIDE AND THE CHUTE AND FLIGHTS BEING SO ARRANGED AND DISPOSED THAT SOME OF THE MATERIAL ELEVATED BY AND DROPING FROM THE FLIGHTS WILL FALL INTO THE CHUTE THROUGH THE OPEN SIDE THEREOF WHILE THE CHUTE IS IN AN INWARDLY AND DOWNWARDLY SLOPING POSITION TO GUIDE THE RECEIVED MATERIAL INTO SAID DISCHARGE MEANS.