US3365177A - Mixing apparatus - Google Patents

Description

JanQ23, 1968 A. c. DAMAN I 3,365,177

MIXING APPARATUS Filed sg t'. 5, 1965 INVENTOR; ARTHUR c. DAMAN 3 Sheets-Sheet 1 ATTORNEYS 13 1.23, 1968 ,DAM-A- 3,365,177

MIXING APPARATUS Filedsept. 5, 1965 's Sheets-Sheet 2.

in 1 IT.

- I INVENTOR. ARTHUR -c. DAMAN BWM%M v ATTORNEYS Jan. 23, 1968 A. c. DAMAN 3,3 7

MIXING APPARATUS Filed Sept. 5, 1965 3Sheets-Sheet 5 'f v INVENTOR. N ARTHUR c. DAMAN- ATTORNEYS United States Patent 3,365,177 MIXING APPARATUS Arthur C. Daman, Denver, Colo., assignor to Denver Equipment Company, Denver, Colo., a corporation of Colorado Filed Sept. 3, 1965. Ser. No. 484,940 3 Claims. (Cl. 25923) ABSTRACT (IF THE DISCLOSURE A mixer of the helical type for mixing high viscosity materials. The mixer includes helical members having an increased width formed adjacent one end thereof and having sidewalls extending upwardly therefrom, impeller means for effecting a directional change in the flow pattern in the material being mixed, means for supplying a cleaning fluid between the side walls of the helical members, means for supplying, during the mixing operation, a material or a fluid to a predetermined area within the material being mixed to insure positive incorporation therein and intermixing of the added material, and means for supplying, during the mixing operation, a pressurized fluid adjacent the impeller means.

This invention relates generally to a mixin apparatus and more particularly to a mixing apparatus of the helical type incorporating novel features for maintaining and improving flow patterns within the material to be mixed during the mixing operation, novel means for automatically cleaning the helical blade members used therein, and novel means for incorporating a material or fiuid within the material being mixed during the mixing operation.

Mixing apparatuses of the helical type have proven to be particularly advantageous in handling difflcult, highviscosity materials such as are encountered in the manufacture of synthetic rubber, non-Newtonian liquids, and

plastics as well as for mixing slurry fuels with high solids contents. In addition to improving the quality of mixing for such materials, this type of mixing apparatus requires less horsepower and obtains excellent results with shorter mixing times than has been heretofore possible with other types of mixers. Mixers of the helical type are broadly classified into two groupsa vertical helical mixer of the cylindrical type and a cone-type or conical helical mixer. Although the vertical helical mixer of the cylindrical type is generally considered to be most suitable for viscosities varying from 20,000 to 1,000,000 centipoises and the conical helical mixer is generally considered to be best for viscosities above 1,000,000 centipoises, experience has shown that both types of helical mixers can be used to good advantage for handling products with viscosities falling outside of the above indicated ranges.

Although mixers of the helical type have been found to be quite advantageous in mixing certain kinds of materials, it has been found that the mixing performance or capability and the overall mixing rate can be improved considerably as compared with prior art mixers. These improvements result from using a mixing apparatus incorporating therein a helical member having an increased width formed at one end thereof, impeller means for efficiently effecting a directional change in the flow pattern of the material being mixed, novel means for Supplying a cleaning fluid to a portion of one of the helical members used therein, and novel means for supplying a material or a fluid to the material being mixed at a point within such material being mixed to insure positive in corporation therein and intermixing of the added material.

A mixing apparatus constructed in accordance with this invention comprises a longitudinally extending mem- 3,365,177 Patented Jan. 23, 1968 her, a first helical member disposed about a portion of said longitudinally extending member, and a second helical member disposed radially outwardly from said first helical member. The second helical member has an opposite thread to that of the first helical member and beneficially improves the flow pattern of the material being mixed by having an end portion thereof formed of increased width. The longitudinally extending member preferably has impeller means formed adjacent one end thereof for moving a portion of the material to be mixed generally radially outwardly therefrom and toward the area through which the portion of increased width of said helical member travels. The impeller means is mounted upon said longitudinally extending member opposite the end of the second helical member formed of an increased width. The mixer preferably includes means for supplying a fluid to a portion of the second helical member during rotation thereof as well as when said helical memher is stationary. This is accomplished through the use of a container and conduit means which is mounted for simultaneous rotation with said second helical member. A material fluid or reagent may be easily and accurately fed into the material being mixed through the use of a container and conduit means mounted for simultaneous rotation with said second helical member, said conduit means having openings formed therein and positioned at predetermined points within the material to be mixed.

One of the principal objects of this invention is to provide an improved mixer of the helical type incorporating novel means for beneficially improving within the mixer the flow pattern of the material being mixed.

Another object of this invention is to provide a mixer of the helical type incorporating novel means for automatically cleaning the helical member used therein.

Another object of this invention is to provide a mixer of the helical type incorporating therein means for automatically supplying during the mixing operation predetermined quantities of the material to be incorporated within the material being mixed.

Another object of this invention is to provide a mixer of the helical type utilizing a helical member having one end thereof formed of increased width.

Another object of this invention is to provide a mixer of the helical type incorporating therein means for supplying a pressurized fluid to the material being mixed.

Another object of this invention is to provide a mixer of the helical type having impeller means for radially directing a portion of the material to be mixed.

Other objects, features and advantages will be apparent from the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is an elevat-ional view in partial cross section of a mixer of the helical type constructed in accordance with this invention;

FIGURE 2 view is a plan view of the mixing apparatus shown in FIG. 1;

FIGURE 3 is a view taken FIGURE 1;

FIGURE 4 is an elevational view somewhat similar to that of FIGURE 1 but showing the use of a single, outer helical member;

FIGURE 5 is a view similar to that of FIGURE 4 showing the use of a conical helical outer member in lieu of the outer helical member of the cylindrical type; and

FIGURE 6 is a view somewhat similar to that of FIGURE 5 showing the use of a pair of symmetrically disposed conical helical outer members and a modified mixing container.

Referring now to the drawings, and more particularly to FIGURES 13, a preferred embodiment of a mixing apparatus of the helical type constructed in accordance along the lines 3-3 of with this invention is shown comprising a longitudinally extending member 11 a first helical member 12 mounted upon and disposed along a portion of said longitudinally extending member 10, impeller means 14 mounted upon the lower end of longitudinally extending member and extending generally radially outwardly therefrom, a pair of second helical members 16 symmetrically disposed with respect to said first helical member 12 and positioned radially outwardly therefrom, means 18 for supplying a liquid to a portion of each of said helical members 16 during rotation thereof, means 26' for supplying during the mixing operation a predetermined quantity of material or fluid to the material being mixed, means 22 for rotating said longitudinally extending member 10, said first helical member 12, said impeller means 14 and said pair of second helical members 16, a mixing container 24, a support 26 for said mixing container 24, and a shield means 28.

The longitudinally extending member 10, which is attached to a hollow drive shaft 29, has an opening 30 formed therein and extending longitudinally therethrough. Shaft 29 has an opening 31 formed therethrough. Opening 31 interconnects through a swivel joint (not shown) opening 30 with a source (not shown) of pressurized fluid such as compressed gas or air or a liquid which may be admitted through the lower end of longitudinally extending member 10 into the material being mixed for the purpose of achieving a more uniform degree of mixture in the same or less amount of time or for adding a material to be incorporated within the material being mixed. Longitudinally extending member 10 has a check valve 32 mounted in the lower end thereof. Check valve 32 permits the flow of pressurized fluid such as compressed air downwardly through longitudinally extending member 10 and into the material being mixed in the mixing container 24 but does not permit the material being mixed to flow upwardly through longitudinally extending member 10.

The first helical member 12 is securely attached to the outer surface of the longitudinally extending member 10. It will be noted that the first helical member 12 is of a right hand thread construction. It will also be observed that upon rotation of longitudinally extending member 10 in a counter-clockwise manner as viewed from FIG- URE 3, such rotation will result in the first helical member 12 operating as a screw conveyor to move a portion of the material being mixed in a generally downwardly direction along longitudinally extending member 10.

The pair of second helical members 16 are, as previously indicated, disposed radially outwardly from the first helical member 12. Both of said second helical members 16 are firmly secured to the longitudinally extending member 18 by strut means 34. Thus, it will be readily apparent that all of the helical members are mounted for simultaneous rotation with each other and the longitudinally extending member 10. Both of said second helical members 16 preferably have side walls 36 extending in the direction in which said members 16 move the material being mixed which is in an upwardly direction in FIGURE 1. It will be noted that width of both of said helical members 16 is substantially uniform therealong except the lower portion 38 of each said member 16 which is formed of flared construction or of considerably increased width. The purpose of portion 33 being formed of increased width will be later explained. It is to be noted that both of said second helical members 16 are of the left hand thread construction or, in other words, have a thread construction opposite to that of said first helical member 12. Thus, it should be readily apparent that upon rotation of longitudinally extending member 10 in a counter-clockwise direction as viewed from FIGURE 3 both of said second helical members 16 will rotate in the same direction. Upon rotation of said second helical members 16, the flared end or portion 38 of each of said second helical members 16 functions in the manner of a scoop thereby causing a portion of material to be mixed to rise generally upwardly in a direction opposite to the direction of flow of the material disposed adjacent the longitudinal member 10.

The helical mixer shown in FIGURE 1 also contains a means 18 for supplying a liquid to a portion of both of said second helical members 16. Said means 18 comprises a stationary conduit or pipe 40' and a container 42 and a pair of conduits 44 attached to said container 42. The conduit or pipe 40 is connected to a source (not shown) of fluid. The container 42 is securely attached to the outer surface of the longitudinally extending member 10 and rotates therewith. Each of the conduits 44 are connected to the lower portion of the container 42. Each of said conduits 44 have a valve 46 mounted therein for controlling the amount of fluid flowing through said conduits 44. Each of said conduits 44 have a nozzle means 48 mounted on the lower end thereof. Each nozzle means 48 is positioned above a respective one of said second helical members 16 thereby facilitating the directing of a fluid from conduit 40 through tank 42 and conduit 44 onto the upper portion of the second helical member 16.

The helical mixer shown in FIGURE 1 also includes means 20 for supplying a material or a fluid to preselected points within the mixing container 24. This means 20 includes a container 50, conduits 52, and a fill pipe 54. Container 50 is securely attached to the outer surface of longitudinally extending member 1% and thus rotates simultaneously with longitudinally extending member 10 as well as with helical members 12 and 16. Container 50 is preferably positioned beneath container 42 in order to permit container 42 to be filled without shutting down the mixing apparatus. Container 50 is of suflicient size to hold an adequate quantity of material or fluid which might be used for several batch mixing operations. The upper end of conduit 54 contains a removable, ventable plug 56 which, although vented, prevents the material or fluid contained within container 50 from being centrifuged out thereof. Conduits 52 are firmly attached to the lower portion of container 50, the outer surface of longitudinally extending member 10 and to the lower surface of helical members 16 as shown. Conduits 52 have openings 58 through which the material or fluid contained within the container 50 passes into the material being mixed within the mixing container 24. It will be noted that each conduit 52 is constructed with one or more openings 58 of predetermined disposition with respect to the position of the helical members 16. It is important that the openings 58 :be positioned whereby rotation thereof will produce a reduced pressure as compared with the pressure existing within the container 50 thereby insuring a positive feed of the material or fluid contained within the container 50 into the material being mixed within the mixing container 24. It will be readily appreciated that openings 58 cannot be located pointing in the direction of rotation since such positioning would result in material contained within the mixing container 24 entering said openings and thereby interfering with the feeding of the fluid or material contained within container 50 into the material being mixed within mixing container 24. The upper portion of each of the conduits 52 is preferably flexible and mounted within a pinch valve 60. Pinch valve 60 may be appropriately adjusted to control the amount of material or fluid flowing through conduits.

The helical mixer shown in FIGURE 1 also includes a means 22 for rotating longitudinally extending member 10 and the helical members 12 and 16. This means 22 comprises a motor 62, a step cone pulley drive 64 and a worm gear speed reducer 66. The motor 62 is connected to the step cone pulley drive 64 by means of a belt 68. The motor 62 drives the step cone pulley drive 64 which in turn operates the worm gear speed reducer 66 and the longitudinally extending member 10. The motor 62 is supported upon cross member or platform 70. The worm gear speed reducer 66 is maintained in position by member 72 which in turn is supported upon platform 70. The platform 70 is in turn supported by members 28.

A shield 28 surrounds a substantial portion of the mixing container 24 to prevent unnecessary splashing of the material being mixed therein. Mixing container 24 is supported upon member 74 which comprises a part of the support means 26. Member 74 has a pair of parallel recesses 76 formed therein. The tines (not shown) of a forklift may be inserted within recesses 76 for effecting separation between the mixing container 24 and member 74. Member 74 preferably has a recess 78 formed on the bottom surface thereof for the purpose of receiving the tines of a forklift. Member 74 is in turn supported upon members 80 which are attached to the members 28.

Mixing container 24 preferably includes a plurality of radially inwardly extending members 82 which further enhances and facilitates the mixing to be accomplished Within the container 24.

Referring now to FIGURE 4, the helical mixer shown in FIGURE 4 is similar to that shown in FIGURE 1 except that a single second helical member 84 is used in lieu of a pair of second helical members 16 as shown in FIGURE 1, and single conduits 44 and 52 are used in lieu of a pair of such conduits as shown in FIGURE 1. The single second helical member 84 is preferably formed with a smaller pitch than helical members 16 of FIGURE 1. The lower portion 86 of second helical member 84 is flared or formed of increased width similar to the portion 38 for helical members 16 as shown in FIGURES 1 and 3. Since the remaining parts of the helical mixer as shown in FIGURE 4 are substantially identical to those shown in FIGURE 1, further description thereof is not deemed necessary.

The helical mixer shown in FIGURE 5 is quite similar to that shown in FIGURE 4 except that the second helical member 88 is conical in shape. The lower portion 90 is flared or of increased width similar to lower portions 38 and 86 of FIGURES 1 and 4, respectively.

The helical mixer shown in FIGURE 6 is similar to that shown in FIGURE 1 except that a pair of conical helical members 92 are used in lieu of a pair of helical members 16 as shown in FIGURE 1 and a modified mixing container 94 and modified support 96 therefore are likewise used. The lower portions 98 of said conical helical members 92 are formed of increased width the same as helical members 16 of FIGURE 1. It is contemplated that mixiing container 94 will remain more or less stationary with respect to the helical members 12 and 92. Thus, to facilitate removal of the material that has been mixed, the lower portion 100 of mixing container 94 is inclined as shown and is connected to an outlet 162. A valve means 104 is installed in outlet 102. Support means 96 is preferably formed with an opening 106 in which is positioned outlet 102. Member 96 also preferably contains a pair of parallel recesses 108 similar to recesses 76 as shown in member 74 of FIGURE 1. Members 110 are of greater height than the length of outlet 102 to permit the combined container 94 and support member 96 to be placed upon a support without injuring or damaging outlet 102 and valve 104.

The operation of the mixing apparatus shown in FIG- URE 1 is now described. The materials which are to be mixed or blended together are placed within the mixing container 24. Such materials may be deposited in the mixing container 24 when the mixing container 24 is positioned as shown or prior to the positioning of mixing container 24 as shown. Container 50 is filled with the material, fluid or reagent which is to be incorporated into and blended within the material being mixed during the mixing operation. Next, conduit 40 and container 42 are connected to a source of fluid such as a suitable cleaning fluid and the opening 30 formed through longitudinally extending member is connected to a source of pressurized fluid. The motor is turned on and rotary movement is thus imparted to the longitudinally extending member 10, impeller means 14, and helical members 12 and 16.

During the mixing operation, counter-clockwise rotation of right hand threaded, helical member 12 results in helical member 12 operating as a screw conveyor thereby moving a portion of the material to be mixed downwardly along longitudinally extending member 10 and toward the impeller means 14. Upon reaching the lower end of longitudinally extending member 10 the flow pattern thus established by the rotation of helical member 12 undergoes a generally 90 degree directional change, such change being aided or enhanced by the rotation of the impeller means 14 which distributes the material within such flow pattern in a generally radial direction. When the material contained within this flow pattern reaches the vicinity through which the lower portions 38 of helical members 16 travel, such material undergoes another general 90 degree directional change, flowing upwardly toward the top of the mixing container 24 and adjacent the outer periphery thereof. It will be noted that the change in fiow pattern at this particular point is greatly enhanced through the use of the novelly formed portion 38 of increased width or flared in shape. As a matter of fact, the use of a helical member 16 having a portion 38 as described enables a more accurate control of the flow pattern existing within the mixing container 24 while producing a more uniform blend or mixture within a shorter mixing interval. Upon rising to the top, the material contained within the flow pattern then travels radially inwardly and occupies the space vacated by the material which has started its downward movement under the action of rotating helical member 12.

During the mixing operation, the material, fluid or reagent contained within the container 51) is admitted into the material being mixed within the mixing container 24 in a predetermined amount and at selected points. Although the pinch valve 60' normally used in a mixer of this type is manually adjustable, it will be readily appreciated that remotely controlled pinch valves may be used if desired or required. Thus, the admission of a material, fluid or reagent from container 50 into the material being mixed within the container 24 may be appropriately controlled to permit quantities thereof to be admitted continuously, intermittently or at varying rates. Although most mixing operations are performed at a uniform or constant speed of rotation, it will be readily appreciated that where variable speeds are involved the use of remotely controlled pinch valves 60 will provide more accurate control over the quantity of material, fluid or reagent being fed from container 50 through openings 58 formed in conduits 52 since otherwise larger quantities of material, fluid or reagent would be admitted into the material being mixed within mixing container 24 during increased speeds of rotation due to the increased pressure difference existing between openings 58 and the interior of container 50. Increased intermixing is obtained through the admission of a pressurized fluid through opening 30 in member 19.

Upon completion of the mixing operation, the mixing container 24- and its contents are supported in any suitable manner such as through the insertion of the tines (not shown) of a fork lift into recesses 76. Next, member 74 is removed from support member and then the mixing container 24 and its contents are vertically lowered and then removed from the vicinity of the mixing machine. Following this, a cleaning fluid is applied to the upper surface of helical members 16 via conduit 40, container 42, conduits 44 and nozzles 48. It will be noted that the cleaning fluid can be applied to helical members 16 whether or not such helical members 16 are stationary or rotating. The fluid used to clean the helical members 16 normally is exhausted through a drain (not shown) which is disposed in the floor (not shown) beneath the mixing apparatus. If desired, an empty mixing container may be positioned beneath the mixing machine prior to the cleaning of the helical members 16.

Referring now to FIGURE 6, for large batch mixing operations, a modified mixing container 94 may be used which, although removable, normally remains positioned beneath the helical members 12 and 92. Upon completion of the mixing operation, the valve 104 mounted in the outlet 102 leading from the bottom of the mixing container 94 is open and the mixed material is removed. Following the removal of the mixed material, the valve 104 may be left in the open position or closed, as desired, and the cleaning fluid is admitted through nozzles 48. It will be understood that the cleaning fluid will be exhausted through valve 104 to a different place than that to which the mixed material was removed. The operation of the mixing apparatus as shown in FIGURES 46 is quite similar to that described above in connection with FIGURE 1. Although the flow pattern of the material to be mixed will vary slight y between the apparatuses shown in FIG- URES 1 and 4-6, good results are, nevertheless, obtained for each apparatus shown.

From the foregoing, it will be readily appreciated that a new and improved helical mixing apparatus has been described and that improved mixing capabilities as well as increased mixing rates are obtainable through the use of a mixing apparatus constructed in accordance with this invention, Improved mixing capabilities are attributable in part to the use of an outer, helical member having one end thereof of flared construction or formed with an increased width, and through the use of impeller means for efl ect ing a directional change in the flow pattern of the material being mixed. Increased mixing rates are attributable in part to the use of novel means for applying a cleaning fluid to the outer helical member or members.

It is to be understood that this invention is not limited to the exact embodiments of the apparatuses shown and described, which merely are by way of illustration and not apparent to those skilled in the art, and it is therefore intended that the appended claims cover all such changes and modifications. For example, although the conduits 52 may be connected to the container 50 as shown in FIG- URE 1 since the mixer is operated at relatively low s eeds, it will be readily appreciated that the upper ends of the conduits 52 may be connected to said container 50 to insure flow from said container into said conduits 52 notwithstanding the etfects of centrifugal force applied to the fluid disposed within the container during rotation thereof. It is intended that the term helical member as used herein includes helical members of the cylindrical type as well as of the cone or conical types.

What is claimed is:

1. A helical mixer comprising a longitudinally extending member; a first helical member disposed about a portion of said longitudinally extending member and being adapted upon rotation thereof to move a portion of the material to be mixed in a direction longitudinal of said longitudinally extending member; a pair of second helical members disposed about said first helical member and radially outwardly therefrom and mounted for simultaneous rotation with said first helical member, both of said second helical members having an opposite thread to that of said first helical member and being adapted upon rotation thereof to move a portion of the material to be mixed in a direction generally opposite to that in which the material is moved by said first helical member, said second helical members having side walls formed along each side thereof, both of said second helical members having a portion thereof of increased width formed adjacent the end which received a portion of the material to be mixed for initial movement of such material in a direction generally opposite to that in which the material is moved. by said first helical member, means for supplying a cleaning fluid between a portion of the side Walls of each of said second helical members during rotation thereof, impeller means for moving a portion of the material to be mixed generally radially outwardly from said longitudinally extending member, said impeller means being mounted on the end of said longitudinally extending member disposed opposite the portion of each of said helical members having an increased width, means for supplying, during the mixing operation, to a predetermined area immediately adjacent the sides of each of said second helical members a material to be incorporated within the material being mixed, and means for supplying, during the mixing operation, a pressurized fluid adjacent the impeller means, said pressurized fluid supply means including a passageway formed longitudinally through said longitudinally extending member.

2. A helical mixer as described in claim 1 in which said cleaning fluid supply means is mounted to supply cleaning fluid between end portions of the side walls of each of said second helical members.

3. A helical mixer as described in claim 2 in which each of said second helical members are of conical configuration.

References Cited UNITED STATES PATENTS 509,987 12/1893 Wilcox.

879,590 2/1908 Roth 259- 1,724,808 8/ 1929 Snyder 259-23 2,293,009 8/ 1942 Patterson 259-134 X 2,437,917 3/1948 Hoeh 259-24 2,515,713 7/1950 Johnson et a1. 259-134 3,278,166 10/1966 Miles 259-23 X FOREIGN PATENTS 292,479 6/1916 Germany.

586,159 10/1933 Germany. 1,054,811 4/ 1959 Germany.

WALTER A. SCHEEL, Primary Examiner.

l. M. BELL, Assistant Examiner.

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