US1908002A - Mixing apparatus - Google Patents

Description

May K9, 1933.

K. s. vALENj'lNE MIXING APPARATUS 3 Sheets-Sheet l Filed Oct. .'50, 1930 0 May 9, 1933. K. s. VALENTINE 1,908,002

MIXING APPARATUS Filed 00ct. so. 1930 Y 3 sheets-sheet 2 INVENTOR //wa ATTORNEYS MIXING APPARATUS Filed oct. so, 1930 3 sheets-sheet 3 INVENTOR ff/04d' /viA ATTORNEYS Patented May 9, 1933 narran teoaooz HINNFTH S. VALENTINE, @E HOLLIS, NEW YORK, ASSCGNF, T@ EME TURBU-MIKLER CQRPQRATION, NEW EURE, itl.- 'A GOREQFLATXtlN @F NEW YORK tramite azz-iranienne Fpplication filed ctohcr 30, 1.930. @aerial No.. 492,19@

This invention relates to mixing apparatus. lt may be used for mixing true liquids, but is particularly adapted for mixing materials of a class that have been recently denominated pseudo-plastics. As illustrative of pseudoplastic, mention maybe made of heavy dat White paint, asphalt emulsions, and clay slurries. Paper pulp also exhibits some of the characteristics of pseudo-plastics.

To efect rapid and thorough mixing, it is necessary that currents shall'be caused to flow in such manner that the currents intermingle with one another and eect a complete shifting and intermingling of all of the elementary volumes that make up the entire volume of material. For eihcient operation the currents must be induced smoothly and flow smoothly, Without thelformation of areas of vacuum and without splashing or churning otherwise'a heavy braking action is imposed on the moving parts of the apparatus, thus re-f quiring the expenditure of a large amount of power.

' general object of the invention is to provide mixing apparatus which will quickly and thoroughly mix 'a Vquantity of material with a minimum expenditure of power.

` Another object of the invention is to provide mixing. apparatus particularly suited for mixing pseudo-plastics and suspensions of fibrous sollds in water or other liquids.

lA furtherobject of the invention is to'provide simple, effective and efficient mixing apparatus which will operate/smoothly, without vibration. i

Other objects of the inventionwill be obvious from the following description taken in connection with the accompanying drawings.

In the forms of the invention disclosed, a rotary shaft carries one or more impellers comprising a circular flow directing plate concentric with the shaft andcarrying mvolute impeller blades. The l'iow directing plate is inclined with respect to a plane perpendicular to the shaft, so that Vas the impeller rotates, wave motion is set up in the mass of material. This wave motion greatly accelerates the mixing action with the result that a thorou h mixing is obtained in a very short time. he impellers specifically disand 3 of the drawings.

closed are provided with shrouding, which 1s advantageous m mixing certain materials.

For mixing other materials e. g. paper pulp)` the shroudingis preferably omitted.

Fig. 1 of the drawings is a fragmentary vertical section showing one form of the present invention.

Fig. 2 is a section taken on line 2 2 of 1l, on which is mounted a mixing impeller designated as a whole by12. Impeller 12 may be made up of several separate parts, but is shown as cast in onepiece. The impeller comprises a hub 14, surrounded by a circular flow directing p1ate`15, from which projects a series of involute impeller blades 16. Carried by the blades is shroudingas at 17 and 18. l

As best shownin Fig. 1, liow directing plate 15 isv inclined wi'threspect to a plane perpendicular to shaft 11. As the impeller rotates, the discharge along any given radius of the tankgradually shifts from a downward inclined direction to an upwardly inclined direction and then back to a downwardly inclined directiom- This shifting of the direction of discharge of the impeller takes place gradually' and cyclically, thereby causing a smoothvertical wavemotion in the material being mixed. This wave 'motion greatly accentuates the mixing action, without placing any substantial braking force on the impeller; i

In the form of impeller shown in Figs. i 1, 2 and 3, all of the impeller blades start at,

a distance from the hub and extend to a considerable distance beyond the edge of ow directing plate 15. The impeller shown in Fig. 4 differs in that only alternate blades 20 are similar to-the blades' 1 6 in Figs. 1 to 3, while the intermediate blades 21 begin at the hub 22 and extend clear across and beyond plate 23. Shrouding is provided at 24 and 25. For mixing some materials, the

5 form of impeller shown in Figs. 1 to 3 is preferable, and for mixing other materials the form shown in Fig. 4 is preferable.

ln Fig. 5 a tank or container has depending therein a shaft 31,-provided with two impellers designated as a whole by 32 and 33, respectively. The lower portion of the shaft may be reduced as at 31; the impellers separated by a spacing sleeve 34 and clamped by a nut 35. Each of the impellers shown .in this figure is of the same construction as the impeller shown in Figs. 1, 2 and 3, inclusive. The impellers are preferably mounted on shaft 31 in corresponding rotative position as shown in the drawings, but may be mounted 180 apart. Both impellers rotate in the same direction and at the same speed. Each of the impellers sets up a vertical wave motion in the material being mixed; and the interaction between the two sets of waves results in an exceedingly rapid and thorough mixing. Since both impellers rotate in the same '.direction, the inter-action between the two wave motions takes place smoothly, without agitation or churning.

As clearly shownv in Fig. 1, material is drawn into the impeller from both top and bottom, and. is directly outwardly by the flow directingplate 15,.andblades 16. The dispeller'until it has passed a considerable distance beyond the periphery of the How directing plate 15. Thus the streams coming from the top and bottom of the tank will so mix that some of the material from the bottom of the tank will be discharged to the top of theftank, and vice versa.

This action is greatly accentuated by the tilt of flow directing plate 15. Consider the right hand side of the impeller for the instant shown in Fig. 1.. Half of the intake of the impeller comes from the top of the tank and half comes from the bottom of the tank; but since the direction of discharge is inclined downwardly, the major portion ofthe instantaneous discharge is to the bottom of the tank. Conversely for the left hand side of the impeller for the instant shown in Fig.

1. Half of the intake is from theftop of the n tank, and half from the bottom of the tank; but since the direction of discharge is inclined upwardly, the maj or portion of the instantaneousdischarge is to the top of the tank. Thus the net result for the entire impeller is that a very flarge portion ofY the i material drawn from the bottom of the tank is discharged to the top of the tank, and vice versa.

The amplitude of the vertical wave motion is determined by theiangle of inclination of s the flow directing plate 15. The optimum charged material is not released by the im.

angle of inclination varies somewhat with the particular material being mixed, but 1 found that for. most purposes an angle between 4 and Z1/f is preferable. too great, churning action results, which laces a heavy braking action upon the impeller. I have found if the angle-be increased beyond 25, this churning action becomes very objectionable.

To obtain smooth action the impeller should be balanced, both` statically and dynamically. The dynamic balance should take into consideration, the kinetic energy of the currentsmoving against the impeller, so that there will be no tendency for the impeller to vibrate, shift its center of rotation,

If the angle be or place a bending moment on the shaft, when the impeller is in operation.

It is realized that the present invention may be embodied in forms other than those particularly disclosed, and hence the present disclosure is merely illustrative in compliance with the patent statutes and is not to be considered as limiting. f

What I claim is:

1. Non-churning mixing apparatus com` prising a shaft; a flow directing plate carried by said shaft, said plate being inclined approximately 6 degrees with respect to a plane perpendicular to the shaft; and a plurality of vinvolute impeller blades projecting from opposite sides of said plate.

2. Non-churning mixing apparatus comf prising a shaft; a flow directing plate carried by said shaft, said plate being inclined approximately 6 degrees with respect'to a plane perpendicular to said shaft; and a plurality of impeller blades projecting outwardl beyond the edge of said plate.

3. lyon-churning mixing apparatus coinprising a shaft; a flow directing plate carried by said shaft, said plate being inclined approximately 6 degrees with respect to a plane perpendicular to said shaft; a plurality of impeller blades projecting out prising a shaft; a plurality of impellerVY blades rotatable with said Shaft, said blades being disposed with their center lines in a plane inclined at an angle of 4to 10 degrees with respect to a plane perpendicular to the shaft; and shroudmg carried by said blades.

6. Non-churning mixing apparatus comprising a shaft, a flow'directing plate carried by said shaft, said plate being inclined at an angle of 4 to 71/2 degrees with respect to a plane perpendicular to the shaft; a plurality of involute impeller blades projecting from opposite sides of said plate; and shrouding carried by said blades.

7. Mixing apparatus comprising a hub; a substantially circular plate concentric with said hub, said plate being inclined with respect to a plane perpendicular to the axis of said hub; and a plurality of involute impeller blades projecting from said plate, certain of said blades extending to said hub and other of said blades terminating short of said hub.

8. Mixing apparatus comprising a hub; a substantially circular plate concentric with said hub, said plate being inclined approximately 6 degrees with respect to a plane perpendicular to the axis of said hub; and a plurality of involute impeller blades projecting from said plate, certain of said blades extending to said hub and other of said blades terminating short of said hub.

9. Non-churning mixing apparatus com prising a hub; a substantially circular plate concentric with said hub, said plate being inclined approximately 6 degrees with respect to a plane perpendicular to the axis of said hub; and a plurality of involute impeller blades projecting from opposite sides of said plate and substantially perpendicular thereto. f

10. Non-churning mixing apparatus comprising a shaft; a-plurality of flow directing plates mounted in spaced relation on said shaft for rotation in the same direction, each of said plates being inclined with respect to a plane perpendicular to the axis of the shaft; and a plurality of impeller blades projecting from each of said plates.

11; Non-churning mixing apparatus comprising a shaft; a plurality of flow directing plates mounted in spaced relation on said shaft for rotation in the same direction, each of said'plates being inclined with respect to a plane perpendicular to the axis of the shaft and the plates being parallel to one another; `.and a plurality of impeller blades projecting from each of said plates.

12. Non-churning mixing apparatus comprising a shaft; a plurality of flow directing plates mounted in spaced relation on said shaft for rotation in the same direction, each of said plates being inclined with respect to a plane perpendicular to the axis of the shaft; and a plurality of involute impeller blades projecting from opposite sides of each of said plates.

13. Non-churning mixing apparatus comprising a shaft; a plurality of liow directing plates mounted in spaced relation on said shaft for rotation in the same direction, each of said plates being inclined with respect to a plane perpendicular to the axis of the shaft and the plates being parallel to one another; and a plurality of involute impeller blades projecting from opposite sides of each of said plates.

14. Non-churning mixing apparatus comprising a shaft; and a plurality of impellers mountedin spaced relation on said shaft for rotation in the same direction, each of said impellers comprising a plurality of blades having their center lines located in a plane which is inclined with respect to a plane perpendicular to said shaft, and shrouding carried by said blades.

15. The method of mixing a body of Huid material without churning the same which comprises drawing two main streams of the material toward one another from opposite directions, subdividing each of the main streams into a plurality of secondary streams, discharging the secondary streams in directions outwardly of the main streams while commmgling the secondary streams from one mam stream with respective secondary streams from the other main stream, and gradually and cyclically shifting the angle between the secondary streams and the main streams.

16. The method of mixing a body of fluid i material without churning the same which comprises establishing an annular generally horizontal mixing zone; drawing two main streams of material to the zone, one from above the zone and the other from beneath theY zone; mixing material from one stream with material from the other stream in proporj tions varying in different parts of the mixing zone; discharging obliquely upwardly the elemental streams ofthe mix containing a preponderance of material drawn from beneath the mixing zone; and discharging obliquely downwardly the elemental streams of the -mix containing a preponderance of material drawn from above the mixing zone.

17. Non-churning mixing apparatus comprising a shaft; a flow directing plate carried y said shaft, said plate being inclined at an angle of A4 to 10 degrees with respect to a plane perpendicular to the shaft; and a plurality of involute impeller blades projecting from opposite sides of said v late.

\ KENNETH S. VALENTINE.

Images