Mixer

May 3, 1966 _L. _A. mikkelsen 3,249,342

MIXER Filed July 14, 1964

35^1

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ATTORNEY

3,249,342

Patented May 3, 1966

United States Patent Office

3,249,342 MIXER

Laurits A. Mikkelsen, 10353 Amboy Ave., Pacoima, Calif. Filed July 14,1964, Ser. No. 382,616

Claims. (Cl. 259—138)

This invention relates to a mixer and more particularly to a mixing device which simultaneously circulates the mixture and at the same time cuts up lumps of the material which are not readily mixing.

The present invention is particularly useful in the mixing of thin wall plaster which is to be applied over wallboard. The plaster is added to water and it is necessary to thoroughly mix these materials in order to obtain the desired consistency for application to the wallboard. Mixers with helical blades have been utilized for moving one material through another for mixing purposes. However, these mixers have no means by which the lumps of material, such as the plaster mix, can be cut up at the same time as the mixing is taking place. Therefore, an excessive amount of time is required to obtain a uniform mixture since the lumps of plaster are difficult to break up simply by stirring action of the helical blade.

The mixer of the present invention utilizes a helical blade mounted around a frame for mixing the plaster with the water and the frame carries a plurality of cutters extending transversely across the axis of the helical blade. The cutters, such as wires, slice through lumps of material and provide a cutting action which is independent of the mixing action of the helical blade. Thus, dry material can be mixed with a fluid material by the movement of the substance with the helical blade and by severing lumps of dry material which becomes wet around the circumference only. The mixing device is spring suspended for manual movement through the mixture and by moving the mixer through all parts of the material, the cutting and mixing action can be uniformly applied throughout the body of the mix. When a cone shaped mixing container is utilized, the mixer has the same taper as the container so that the mixer can be placed very near to the walls of the container and when the mixer is at the bottom of the container, it mixes the material in the entire bottom of the container.

It is therefore an object of the present invention to provide a mixer for mixing materials together by moving the materials by a helical blade and by cutting through the material by a plurality of cutters.

Another object of the invention is to provide a mixer in which the materials to be mixed are moved along the axis of the mixer by a helical blade and the materials are simultaneously cut by cutter wires extending transversely of the axis of the helical blade.

A further object of the invention is to provide a mixer which is suitable for mixing of fine powdered material with a liquid said mixer moving the powdered material through the liquid by means of a helical blade and cutting up lumps of the dry material with cutters consisting of wires rotating with the helical blade.

These and other objects of the invention not specifically set forth above will become readily apparent from the accompanying description and drawings in which:

FIGURE 1 is a side elevational view, partly in section, of the mixer in a container and illustrating the spring suspension for the motor;

FIGURE la is a partial sectional view similar to FIG2

URE 1 showing the mixer in a different position within the container;

FIGURE 2 is an enlarged perspective view of the mixer showing the helical blade and the transverse cutting wires; 5 FIGURE 3 is a side elevational view of a modification of the mixer in which the top circular band is eliminated;

FIGURE 4 is a perspective view of the modified mixer of FIGURE 3;

FIGURE 5 is a perspective view of another modifica10 tion of the invention in which the mixer frame is square instead of tapered.

Referring to the embodiment of the invention chosen for purpose of illustration, mixer device 10 consists of a frame 11 which has a top cross member 12, a bottom 15 cross member 13 and tapered sides 14 and 15. Sides 14 and 15 are connected at their ends to the cross members 12 and 13. Shaft 16 passes through and is secured at its end to cross member 13. A circular ring 17 of flat metal is supported by the cross member 12 while a cir20 cular ring 18 of the same material is supported by the cross member 13. A helical blade 19 in the form of a flat metal band is attached at end 20 to the top circular ring 17 and follows a helical path around frame 11 to the point where end 21 attaches to bottom ring 18. The 25 blade 19 is attached to sides 14 and 15 at points 25 and 26, respectively, where the blade passes the side members. It is understood that a suitable welding or brazing process can be used to connect the frame members together and to connect the blade to the frame members. A plurality 30 of spaced cutter wires 30 extend between the sides 14 and 15 and through the shaft 16 and each wire is attached to the sides and to the shaft. The wires 30 can be evenly spaced along the helical axis of the blade between the top and bottom cross members 12 and 13 or the spacing can 35 be varied.

As illustrated in FIGURE 1, shaft 16 is connected by a coupling 31 to a motor 32 having handles 33 and the motor is suspended by a coil spring 34 attached to a horizontal arm 35 of frame 36. The substances to be mixed ⁴⁰ are placed in a conical container 40 which is supported by a ring 41 carried by stand 42 having three legs 43, only two of which are shown. The bottom outlet 45 of the container is normally closed by a plate 46 which is connected to a movable linkage 47 supported in any suit45 able manner by the frame 42 for movement relative to the frame in order to pivot the plate 46 about pivot 48 into the open, dotted line position illustrated in FIGURE 1. The frame 36 is attached to the frame 43 for rigid support over the open end of the container 40. As illus50 trated in FIGURE 1, the sides 14 and 15 have the same taper as the conical shaped container 40 so that when the mixer 10 is positioned in the lowest part of the container, it substantially covers the lower end of the container 40.

When it is desired to mix two substances together, ³³ such as water and thin wall plaster, water is first placed into the container 40 while the plate 46 is in closed position. Thereafter, a sack of dry plaster is poured into the water within the container. The two substances fill the conical container about half full so that the materials 60 will not splash out of the container during the mixing operation. In one example, about five gallons of water is placed in a container about four feet high and an 80 pound sack of plaster is then added to the water.

Missing of the substances in the container is com65 menced by starting motor 32 and the operator grips the handles 33 of the motor to move the mixer device 10

3,349,342 around in ths container. Rotation of the mixing device 1® causes the helical blade 19 to move both the water and the plaster axially along the shaft 16 in a direction determined by the direction of rotation of the shaft. When mixing plaster, the shaft preferably rotates clockwise in order to pull the dry plaster downwardly into the liquid and the mixture will be moved toward the bottom of the container where it will reverse and flow upwardly through the container as illustrated by the arrows of FIGURE 1. However, if the mixer 10 is driven counter-clockwise, the materials will be moved toward the top of the mixture. The helical blade 19 can be made of sufficient width to provide the desired flow of material since the amount of material that is moved increased with blade width. For mixing dry wall plaster, the blade can be about one quarter inch wide and about one-sixteenth inch thick for stability. Also, the velocity at which material mixes can be controlled by controlling the speed of the motor 31. Thus, the time required to complete the mixing process will be effected by blade width and motor speed.

When a fine dry material, such as plaster, is mixed with a liquid, the dry material tends to become coated with liquid and form plaster lumps within the liquid which are difficult to break up solely by a stirring action. These lumps move with the mixture and are cut up by the wires 3® which extend transversely to the direction and movement of the mixture. As the material moves through the helical blade area, the lumps are cut successively by the spaced wires 3® so that the resulting lumps become smaller and smaller and make them easier to mix. The cutting wires are spaced apart to permit the material to flow past the wires while still providing a cutting action. During the mixing operation, the spring suspension 34 of the motor makes it easy for the operator to move the mixer 10· around within the mixture into position such as illustrated in FIGURE la so that all of the material will be subject to the mixing action of the mixer device 10. By moving the mixer up and down and transversely in the liquid, all lumps can be cut up and all the material moved around to become thoroughly mixed.

A modification of the invention as illustrated in FIGURES 3 and 4 wherein the top ring 17 is eliminated and the top end 20' of the blade 19' connects directly to the top frame member 12. The lower end 21' of the blade connects with lower ring 18. Another modification of the invention is illustrated in FIGURE 5, wherein mixing device 59 comprises a frame 51 which is square in shape. The frame 51 consists of top and bottom cross members 52 and 53, respectively, which are connected by sides 54 and 55. The shaft 16 passes through and is secured to cross member 52 and the shaft end is secured to cross member 53. The sides 54 •and 55 are connected to the cross members 52 and 53 at their ends. A helical blade 56 surrounds the frame 51 and is attached to the sides 54 and 55 at points 57 and 58, respectively. The end 69 of the blade is connected to the end of cross member 52 while the end 61 is connected to a lower ring 62 which is connected at points 63 to the lower cross member 53. A plurality of cutting wires 64 extend between the sides 54 and 55 •and pass through the shaft 16. The ends of the wires are secured through the side members by welding or in any other suitable manner. The device 50 illustrated in FIGURE 5 can be used in cylindrical tanks and can be moved up and down in such a tank parallel to the side wall of the tank. The helical blade 55 serves to move the material in the same manner as the blades 19 and 19' of the other embodiments and the wires 64 serve to cut up any lumps of material which are not being mixed.

It is apparent that the use of top and bottom rings, such as 17 and 18 in FIGURE 2, permit the helical blade to be attached to the ring at any point around its circumference whereas in the embodiments of FIGURES 4 and 5, the blade starts, at the end of the top cross piece although it can end at any location around the bottom ring. Mixers of other shapes than tapered 5 or square can be constructed for particular purposes and the size of the mixer is determined by the materials to be mixed and the size of the container in which the mixing is to be done. After the materials are properly mixed, the mixture is discharged from the container by opening the valve, such as plate 46. It is understood that more than two substances can be mixed and that the overall size of the mixing device can also be varied for operating on the intended materials. Also, the frame can comprise more than two cross members and 15 side members which are located in different planes transverse of the shaft so that the helix will be supported at more locations and straight cutting wires can run between different frame members at an angle to one another. Various other modifications are contemplated by 20 those skilled in the art without departing from the spirit and scope of the invention as hereinafter defined by the appended claims.