US3203674A

US3203674A - Mixing apparatus and method

Info

Publication number: US3203674A
Application number: US225570A
Authority: US
Inventors: James W Watson
Original assignee: Swift and Co Inc
Current assignee: JBS USA LLC; Endoscopic Technologies Inc
Priority date: 1962-09-24
Filing date: 1962-09-24
Publication date: 1965-08-31
Anticipated expiration: 1982-08-31

Description

19965 J. w. WATSON 3,203,674

MIXING APPARATUS AND METHOD Filed Sept. 24, 1962 2 Sheets-Sheet 1 IN VEN TOR. James VIZ/111a:- Watscrn Aug. 31, 1965 J. w. WATSON MIXING APPARATUS AND METHOD 2 Sheets-Sheet 2 Filed Sept. 24, 1962 INVENTOR. James SA/[Hist Wafis an United States Patent Office 3,203,674 Patented Aug. 31, 1965- 3,203,674 MIXIYG APPARATUS AND lVIETHGI) James W. Watson, Lansing, Ill., assignor to Swift & Company, Chicago, Ill, a corporation of Illinois Filed Sept. 24, 1962, Ser. No. 225,570 14 Claims. (Cl. 259-3) This invention relates to an improved method and apparatus for the batch mixing of materials. More particularly, this invention relates to a method for mixing or granulating material in a rotary drum mixer and for discharging the material therefrom; and to an improved rotary drum mixer having an improved discharge device.

In the past, rotary drum mixers have generally consisted of a rotatable drum having an opening in the center of one end for introducing materials to be processed and an opening in the center of the other end for discharging the processed material. A door is generally located at the discharge end for closing the opening when filling and mixing. A series of longitudinal flights are generally located within the drum. These flights pick up material from the bottom of the drum and shower the material from the top of the drum as it rotates. To effect the discharge, the door is removed from the discharge end of the drum and a chute is inserted through the center opening. This chute intercepts the showering material and diverts it through the opening to the outside of the drum.

Where it is desired to roll the materials along a smooth surface to mix and agglomerate them as in granulation, the flights have been found to interfere with the desired rolling action. Many attempts have been made to modify the conventional rotary mixer to overcome this problem. These modifications usually consist in some manner of shortening the height of the flights. By such modifications, an attempt is made at achieving a rolling bed such as is found in a continuous granulator. However, since the flights are only partially removed, the rolling bed falls short of that found in a continuous granulator and thus granulation is only partially affected. Further, the alteration of the flights slows the speed of discharge since the material must still be raised and showered onto a chute for discharge through a center opening. These shorter flights carry less material, and hence must make more revolutions in order to discharge the same amount of material as conventional flights.

It is therefore an object of this invention to provide an improved granulator.

Another object of this invention is to provide an improved rotary drum mixer having a continuous, uninterrupted interior wall.

Another object of this invention is to provide an improved discharge device for a rotary drum mixer.

Another object of this invention is to provide an improved method for granulating material in a rotary drum.

Still another object of this invention is to provide an improved method of discharging material from a rotating granulator.

Other objects and advantages will become apparent from the following description and drawings.

Briefly, my invention comprises sealing one end of a rotatable cylindrical zone, introducing material into the zone, rotating the zone, and opening an annular area about the periphery of said one end of the zone to allow a selected amount of said material to pass out of the zone through said annular opening. This method may be implemented by a hollow cylindrical means having a continuous uninterrupted inner surface, a 'means connected to said cylindrical means for imparting rotary motion thereto, and closing means connected to one end of said cylindrical means, said closing means being adapt ed to completely seal' the end of the cylindrical means during mixing .and to open an annular area about the periphery of the end of said cylindrical means for discharging material therethrough. The system may be used with either batch type or continuous type operations by regulating the size of the annular opening and the amount of time which it is open. The closing means preferably is, in effect, an expandable door and comprises an expandable closure means mounted between.the discharge end of the cylindrical means and an end member spaced therefrom. The expandable means is preferably an inflatable tube, mounted in such a manner that when the tube is inflated, it will fill the space between the discharge end of the cylindrical means and the end member. Whenthe tube is deflated, it contracts leaving an annular spacebetween the discharge end of the cylindrical means and'the end member.

While my invention may be eflectively used for various purposes, it hasbeen found to be particularly effective in granulating'plant food of fertilizer. In this process the lower end of iacylindrical zone is sealed and the zone is rotated. Solids and liquids are introduced into the interior of the zonelthrough an opening in the center of the higher end. After the solids and liquids have remained in therot'ating zone for a suflicient period to form granules, or to receive any other desired treatment, an annular area is opened about the periphery of' the lower 'end of thev'zone, and the treated material is allowed to pass out of the rotating zone through the am nular opening.

It is readily apparent that the method of discharging through an annular opening, which may be sealed by an inflatable tube or similar device, has the unique advan-. tages of: 1) providing a rolling bed such as would be found in a continuous. granulator, (2) allowing the bed to be treated with various liquids, (3) allowing the agglomeration ofmaterial to form granules without the detrimental interference of flights, and (4) allowing the granules to flow rapidly out of the mixer by natural means as the mixer rotates.

Further objects and advantages of my invention may be more fully understood from the following description and drawings wherein:

FIGURE 1 is a side elevation, in a vertical section, of a preferred embodiment of my invention with the' discharging means in the open position.

FIGURE 2 is a side elevation, in vertical section, of a portion of the same embodiment showing the closing means 'in closed position. i

FIGURE? 'is an end elevation taken along line 3-3 of FIGURE 1.

FIGURE 4 is a side elevation in vertical section of a portion of a modification of the device shown in FIG- URE 1. V

FIGURE 5 is a side elevation in vertical section of a portion of another modificationof the device shown in FIGURE 1.

FIGURE 6 is a side elevation in vertical section of a portion of still another modification of the device shown in FIGURE 1. I

The present method will be better explained through a description of the structure and operation of apparatus by which it is practiced. It will become apparent that all forms of the apparatus include a rotatable drum, an end member spaced from the drum, and an expandable annular means located between the drum and end member.

Referring to FIGURES 1, 2 and 3, the preferred apparatus is a cylindrical drum 10 having an inclined longitudinal axis and tracks 12 about the periphery thereof. The tracks 12 ride on-rollers 14 which support the drum and allow it to rotate about its longitudinal axis. A ring gear 16 is attached to the periphery of the drum 10 and is engaged by a pinion 18 mounted on the output shaft of a power source 20. When the power source 20 is energized, pinion 18 is revolved causing ring gear 16, and hence drum 10, to rotate. A central opening 22 is provided in the higher end of drum 10 for the introduction of materials. The opening is centrally located and small enough to prevent material within the rotating drum from discharging therethrough.

A hopper 48 is located directly beneath the opposite, and lower, discharge end of drum 10 to receive the material therefrom. A substantially circular rim 24 is mounted in the center of the discharge end of the drum 10 by means of a plurality of brackets 26 which are rigidly attached to the outer wall of the drum 10 and to the outer side of the rim 24. Securely mounted about the periphery of the rim 24 is an inflatable annular tube 28 having an internal air chamber 30. Astem 32, extending from the inflatable tube 28, connects the air chamber 30 with a radial tube 34 mounted internally of rim 24. Tube 34 leads to a junction 30 located in the center of rim 24. An air line 38 is journaled through an air-sealed bearing 40 into the junction 36. The air line 38 is bifurcated and connected through

valves

42 and 44 shown illustratively, in FIGURE .1, respectively to sources of air under pressure and vacuum (notshown).

As described, the drum has an inclined longitudinal axis to aid in discharging its contents by gravity; however, the slope is not essential to the operation of the apparatus. Also, it will be readily apparent that in many applications a connection to a source of vacuum will not be necessary since the nature of the inflatable tube will be to return to its uninflated posture upon disconnecting the pressure source. Obviously, deflating tube 28 tends to decrease the outside diameter of a discharge end, formed by rim 24 and tube 28, of the cylindrical zone formed generally by drum 10.

FIGURES 4, 5 and 6 represent further embodiments of the apparatus shown in FIGURES l, 2 and 3. Details of the connection of the inflatable means to sources of air under pressure and vacuum have been omitted in the interest of clarity. However, it will be apparent that such connections may be similar to that shown in FIGURE 1, or otherwise within the knowledge of a person skilled in the mechanical .arts.

Referring to FIGURE 4, an annular tube support, or channel, 52 is formedin, or otherwise attached to, the periphery of one end of a drum 10'. An inflatable annular tube 54, which is adapted to expand inwardly of the drum, is mounted in the tube support 52. A circular end plate 56, of a diameterless than the drum 10', having an outer flange 58 is concentrically held within the tube support by means of brackets in such a manner that the outer flange of the end plate is spaced a short radial distance inwardly of the tube support 52 and tube 54. Thus an annular opening is provided between the flange 58 of the circular end plate 56 and the inward surface of tube 54, when the latter is deflated. When the tube 54 is inflated, it expands inwardly contacting flange 58 sealing the end of drum 10'.

Referring to FIGURE 5, an annular tube support 62 is mounted concentrically on the outer surface and end of a drum 10". A circular end plate 64, approximately equal to support 62 in diameter, is rigidly connected to the tube support by means of brackets 66 and is spaced a short longitudinal distance from the end of drum 10". An inflatable annular tube 68, which is adapted to expand laterally against the circular end plate 64, is mounted within the support 62. The space between the tube 68, when deflated, and the inside wall of circular end plate 64 provides an annular opening 70 through which processed material may pass. When tube 68 is inflated,

it expands laterally contacting the inside wall of circular end plate 64 and closes the end of drum 10".

The modification shown in FIGURE 6 is essentially a reversal of parts of the apparatus of FIGURE 5.

Referring to FIGURE 6, a circular end plate 72, having an annular tube support 74 mounted about its periphery, is concentrically positioned adjacent the end of the wall of drum 10" by brackets 76. The tube support 74 is located between end plate 72 and an end of drum 10". An annular flange 78 is secured about the outer circumference of that end of drum 10" spaced directly opposite the tube support 74. An annular inflatable tube 80, which is adapted to expand laterally into contact with flange 78 to close the end of drum 10", is mounted within the tube support 74. The space existing between the flange 78 and the tube 80, when deflated, provides an annular opening 82 through which material may be discharged from the drum.

Operation of the apparatus of FIGURES 1-3 is illustrative. The drum is charged with materials to be processed after first causing the annular tube 28 to be inflated to close the space between the rim 24 and the end of drum 10. Rotation of the drum is commenced, either before, during, or following the charging step by energizing the motor 20 to turn pinion 18 and cause ring gear 16, and hence drum 10, to revolve. This revolving motion is also imparted to the end member, namely, rim 24, which is rigidly secured to the drum. The pressure of the contact between the drum wall and the inflatable tube is suflicient to effectively seal the end of drum 10 against escape of the materials therein. The material is allowed to remain in the revolving drum until it has received the desired treatment. When the treatment is complete, the annular tube is deflated by connecting it to the atmosphere or by closing valve 42 and opening valve 44 to positively withdraw the air from air chamber 30. Upon deflation, an annular opening is exposed at the end of the drum 10 and the treated material will discharge therethrough by gravity and rotation.

It is clear that many modifications and variations of the invention as hereinbefore set forth may be made without departing from its spirit and scope, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. An improved method of discharging material from a rotatable cylindrical zone comprising: rotating the cylindrical zone and opening an annular area about the periphery of one end of the rotating cylindrical zone by decreasing the outside diameter of said end of said zone to allow the material to be discharged through said annular area.

2. An improved method for processing material in a rotating cylindrical zone comprising: sealing one end of the rotating cylindrical zone; introducing material into the cylindrical zone; and decreasing the outside diameter of said end thereby opening an annular area about the periphery of said one end of the rotating cylindrical zone to allow a selected amount of the material to pass therethrough.

3. An improved method for treating material in a rotatable cylindrical zone comprising: closing one end of the cylindrical zone; introducing the material into the zone through an opening in the center of the other end of the zone; rotating the zone; allowing the material to remain in the rotating zone for a sufficient period of time to accomplish the desired treatment; opening an annular area about the periphery of the sealed end of the zone by decreasing the outside diameter of said end; and discharging a selected amount of the processed material from the zone through the annular opening while rotating said zone.

4. An improved method for granulating plant food materials comprising: introducing the materials into a closed cylindrical zone; rotating said cylindrical zone about its longitudinal axis to mix and agglomerate the materials; decreasing the outside diameter of one end of said zone to create an annular opening about the periphery of said zone at one end thereof; and discharging the mixed materials through said opening while rotating said zone.

5. An improved rotary mixing device comprising: a hollow cylindrical means; means connected to said cylindrical means for imparting rotary motion about the longitudinal axis thereof; and closing means connected to one end of said drum, said closing means being adapted to expand to seal said end of the cylindrical zone dur ing mixing and to contract to open an annular area about the periphery of said end of said cylindrical zone for discharging material therethrough.

6. An improved rotary drum mixed comprising a cylindrical means having an inclined longitudinal axis; means connected to said cylindrical means for imparting rotary motion about said axis; means located at the higher end of said cylindrical means for allowing the introduction of materials to the interior of said cylindrical means; and closing means located at the lower end of said cylindrical means, said closing means being adapted to expand to seal said lower end of said cylindrical means and to contract to provide an annular discharge area about the periphery of said lower end of said cylindrical means.

7. An improved rotary drum mixer comprising a rotatable cylindrical drum having a charging end and a discharge end; an end member spaced adjacent the discharge end of said drum; an annular expandable closure means positioned between said discharge end of said drum and said end member, said closure means filling the space between said drum and said end member only when expanded; and means to expand and contract said closure means.

8. An improved rotary drum mixer comprising a rotatable cylindrical drum having a charging end and a discharge end; a substantially circular end member spaced adjacent the discharge end of said drum, said end member being connected to said drum at spaced locations so as to be rotatable therewith; an annular expandable closure means mounted on one of said drum and said end member in opposition to the other positioned between said discharge end of said drum and said end member, said closure means filling the space between said drum and said end member only when expanded, and means to expand and contract said closure means.

9. An improved plant food mixer comprising: a cylindrical drum having a smooth continuous uninterrupted inner wall; means connected to said drum for imparting rotary motion thereto; means located at one end of said drum for allowing the introduction of materials to be treated and for preventing their discharge therethrough; and closing means located at the other end of said drum, said closing means comprising a rim mounted in the center of said other end of said drum, an annular inflatable means disposed about the perimeter of said rim and adjacent to said inner wall of said drum, said inflatable means being spaced from the said inner wall of said drum when deflated and in contact with said inside wall of said drum when inflated; and means operatively connected to said tube for inflating and deflating such inflatable means.

10. An improved discharge device for a rotary drum mixer comprising: an expandable door mounted in the discharge end of the drum, said expandable door being adapted to expand to seal the end of the drum and to contract to provide an annular discharge area about the periphery of said end of said drum.

11. An improved discharge device for a rotary drum mixer comprising: a rim mounted in the center of one end of the drum; an inflatable annular tube disposed about the perimeter of said rim and adjacent to the inside wall of the drum, said inflatable tube 'being spaced from the inside wall of the drum when deflated and in contact with the inside of the wall of said drum when inflated; and means operatively connected to said tube for inflating and deflating said tube.

12. An improved discharge device for a rotary drum mixer comprising: a tube support mounted concentrically on the outer surface of one end of the drum; a circular end plate connected to the drum and spaced a short lateral distance therefrom; an inflatable annular tube mounted within said tube support and adjacent to said end plate, said inflatable tube being spaced from the end plate when deflated and in contact with said end plate when inflated; and means operatively connected to said tube for inflating and deflating said tube.

13. An improved discharge device for a rotary drum mixer comprising: an annular tube support mounted on one end of the drum; a circular end plate concentrically mounted on the tube support with the outer edge of said end plate being spaced a short radial distance inwardly of the tube support; an inflatable annular tube mounted within said tube support and adjacent said outer edge of said end plate, said tube being spaced from the outer edge of said end plate when deflated and in contact with said end plate when inflated; and means operatively connected to said tube for inflating and deflating said tube.

14. An improved discharge device for a rotary drum mixer comprising: a circular end plate mounted adjacent the end of the drum; an annular tube support mounted on said end plate between the end plate and the end of the drum; an inflatable annular tube mounted in said tube support and adjacent the end of said drum, said tube being spaced from the end of said drum when deflated and in contact with the end of the wall of said drum when inflated; and means operatively connected to said tube for inflating and deflating said tube.

References Cited by the Examiner UNITED STATES PATENTS 539,568 5/95 Bride 277-34 X 849,732 4/07 Flora 259-171 1,074,388 9/ 13 Stedman 259-175 1,379,586 5/21 Faber 259-175 1,834,988 12/31 White 277-34 X 2,497,736 2/50 Muller 259-175 3,038,488 6/62 Welch et al. 277-34 X 3,042,360 7/62 Sneddon 198-65 X FOREIGN PATENTS 1,054,798 4/59 Germany.

CHARLES A. WILLMUTH, Primary Examiner.