US1960030A - Mixing machine - Google Patents

Description

May 22, 1934. A, SACKETT 1,960,030

MIXING MACHINE Filed 15, 1931 /.9 '6

Patented May 22, 1934 NITED STATES MIXING MACHINE Application August 15,

16 Claims.

The invention relates to a machine for mixing a gaseous or vaporous chemical reagent with a solid, the particular object in view in connection with the development of the present machine being the mixing of nitrogen most conveniently supplied to the machine in the form of liquid anhydrous ammonia or ammonia gas with commercial phosphates most easily obtainable in the form of ground bone or ground phosphate rock. This material, to make it available for the purposes in hand, is to the best advantage first treated with acid and thus changed to the commodity known in the fertilizer trade as super phosphate. The references hereinafter contained to comminuted solid material, have particular reference to super phosphate and other solids capable of being directly combined with gases as anhydrous ammonia and the like. The machine in the form of the invention shown is so devised as to present comminuted phosphate and nitrogen, the latter in an active or nascent form to a mixing cham her in which a mechanical mixer circulates the powdered material and the nitrogen continuously and more or less in an orbital path. In the preferred form the materials discharged from the said mixing chamber are subsequenty treated in another mixing device wherein the solid material is further passed through one or more additional mixing steps to be finally discharged into a hopper from which it is delivered to an elevator for storage or for immediate distribution, as required by the circumstances.

The continuous operation of the machine referred to is of considerable importance as the materials can not be mixed in this way in the required quantities otherwise than by a continuously operating apparatus to which the comminuted material and the reagent are fed continuously and from which the mixed material is continuously discharged, although the machine may be operated for any desired period.

In the accompanying drawing I have illustrated a mixing machine embodying the invention in the preferred form.

In the drawing:

Figure l is a vertical central section on the axis of the rotary mixer also showing the dry mixing units which in the illustration are of the gravity type in section on the same plane.

Figure 2 is a vertical section on the line 2, 2 of Figure 1 in a plane at right angles to the plane of Figure 1.

Figure 3 is a horizontal section on the line :1:, :c in Figure 1.

Referring to the drawing by numerals, each of which is used to indicate the same or similar parts in the different figures, the machine as shown includes a hopper or a funnel 1 into which the dry material is fed. This hopper discharges by way of a slide valve 2, or in any suitable man- 1931, Serial No. 557,257

ner, into a conveyor or feeding cylinder 3 which in the preferred form contains a rotary conveyor 4 of the propeller type which in turn discharges into a mixing drum 6 of double conical form enclosing a rotary mixing beater fan 7 to be further described. The mixing drum 6 is supplied by way of nozzles 8 with liquid vaporous or gaseous material which would ordinarily be nitrogen to be mixed with the comminuted solid material which in the present instance is ordinarily phosphate. The material mixed in the drum 6 is discharged downwardly into a gravity mixer 9 which discharges at the bottom through a discharge pipe 10 into a hopper not shown.

Referring more specifically to the construction illustrated, the slide valve 2 is operated by means of a rack 5 and pinion 5, the latter being secured to a pulley 12 which is rotated from below by means of a cord or belt 14. The rotary conveyor 4 which is fed from the hopper 1 by way of the slide valve 2 or in any convenient manner, receives its rotary motion from a pulley 15 over which a suitable drive belt 16 is passed.

The conveyor 4 is provided with inclined propeller blades 17, which in the form of machine shown, are rotated counterclockwise as seen from the right in Figure 1, to feed the solid material to the right in said figure into the chamber 6. The mixer fan '7 is shown as provided with beater blades 18, which are particularly effective in advancing and drawing in the dry material from the conveyor 4 and circulating it. At the ends of these beater blades 18, which are preferably inclined after the manner of the blades 17 as best shown in section, Figure 1, the mixing beater or fan is shown as provided with fan blades 19, the inner portions 20 of which adjacent the conveyor blades are preferably in a radial plane of the axis, the outer ends at 21 of said fan or mixer blades being bent backwardly at a suitable angle, being shown as deflected backwardly oppositely to the direction of rotation at an angle of about 45 degrees from the radial plane.

The fan shaft 60 preferably carries in addition to the beater and fan blades 18, 19, the clearing blades 61 and 62 on each side of beater fan '7. These extend into close proximity with the casing. They are provided to overcome the tendency of the material to settle and clog in the peripheral corners 63 and 64. Blades 61 are inclined in the same direction as are conveyor blades 17 to throw the material to the right in Figure 1 by counterclockwise rotation. Blades 62 have this inner portion 65 nearest shaft 60 inclined similarly to the conveyor blades 17 to throw the material to the right in Figure 1, but the end portions of these blades are oppositely inclined to remove the material which tends to accumulate in the corner 64. Said end portions are shown at 66.

The anhydrous ammonia or other liquid or gaseous or vaporous material to be mixed with the solid comminuted material is supplied under pressure to the drum 6 by way of pipe 22 which in the form shown encircles the chamber at 24 having nozzles 25 shown as directed inwardly and forwardly at the periphery of the drum in the direction of rotation which is counterclockwise. The pipe 22, as shown, is also connected to nozzles 8 which enter the drum 6 in the vicinity of the conveyor cylinder 3 where it is joined to the drum at 26, said nozzles being preferably directed toward the center of the drum in the direction of motion of the dry material as it enters to be mingled with the stream of particles of dry material. Inaccordance with the preferred practice constituting the method of the invention. The solid material mixed with. the nitrogen or other gas or fluid more or less intimately is circulated by the fan not only in an orbital path about the drum 6 as indicated by the arrows, but downwardly through the discharge opening 27 into the gravity mixer 9, part of it being withdrawn by the action of the fan or mixer upwardly through said open ing 27 into the drum, the main portion of the solid being dropped from the draft or current of gas or vapor and comminuted solid into the top gravity mixing unit 28. This unit 28 in the form of the invention shown consists of concentric cylinders 29, 30, open at the top and bottom, the cross section of the chamber or gravity mixer 9 being closed at this point periodically by doors or shutters 31 shown in open position in Figure 2. The dry material accumulates most rapidly in the center cylinder 29, the shutters 31 being closed, and from this cylinder it overflows into the outer shorter cylinder 30 shown as of less altitude and hence into the peripheral space 32. the cylinder 30 being thus spaced inwardly from the walls of the gravity mixer 9. The doors and shutters 31 are supported or counter balanced in any suitable manner as by means of a weight 23 supported on a belt or band 33, passed over a pulley 34 and divided at 34 where it is led downwardly about the peripherally grooved segments 35 which are secured to the shafts 36 of the shutters or doors 31. When the mming unit 28 has received the predetermined load or batch, sufficient to raise the weight 32, the doors or shutters 31 are opened as shown in Figure 2 dropping the material thus successively distributed in the unit 28 at one time into the lower chamber 37 of the gravity mixer, and thus accomplishing a definite mixing step as in my previous Patent No. 1,590,647, tending to further equalize the previous mixing of the liquid or gaseous and solid material.

Beneath the shutters 31 in the chamber 37 in the form of the invention shown, there is an inwardly disposed conical spreader 38 encircled by a frustro conical annular deflecting or concentrating surface 39. The spreading and deflecting members 38 and 39 have the effect of turning outwardly the material at center and turning inwardly the material at the sides, accomplishing an additional gravity mixing operation.

It is of interest to note at this point that the members 38, 39 are formed with their bottom surfaces also of inclined or conical or frusto conical outline as indicated at 40, 41, and the gravity or dry mixer 9 is formed with its top surface 42 and its bottom 43 also of frustro conical or incline arrangement, and the drum 6 is of double conical form. An object of so constructing and arranging the apparatus is to avoid pocketing of the gas. To avoid building up an excess pressure in the lower chamber due to the action of the ammonia or other chemical upon the solid as phosphata'the chamber 37 below the shutters 31 is connected to the chamber 44 above the shutters by a bypass pipe 45, shown particularly in Figure 2, permitting the gases to escape from the lower with the upper chamber and if necessary to be discharged through the hopper.

Below the spreader and deflector members 38,

39 is still another gravity mixer unit consisting sides into the cylinder 46 and into the space 48 between the outer cylinder and the walls of the mixer. When sufiicient of the material has been accumulated in this mixing unit, the entire accumulation is dropped simultaneously by the opening of shutters 50, 51, hinged to shafts 52, 53 and controlled by segments 54 on shaft 52 operated by weight 55 on split cord 55' as in the previous instance. The segments 54 are connected to the shafts 53 by cranks 55 on said shafts, and connecting rods 56 joins them to said segments or in any suitable manner so that the shutters operate simultaneously.

The operation of the machine has been quite fully described in connection with the description of the structure. The dry material introduced through the hopper l is moved to the right into the drum 6 by the rotary conveyor 4. In the drum 6 it is rapidly circulated by means of the fan 7 having the double blades 18, 19, which beat and circulate gaseous and liquid material at a high speed producing an exceedingly intimate mixture. The circulation in addition to the orbital path carries the material downwardly into the gravity mixer 19 through the opening 27, the bulk of the solid being released from the draft and dropped, and the gas and air being carried back into the drum 6, together with the portion of the solid material which continues in the draft.

In the gravity mixer 9 the solid material already combined with the liquid or gaseous chemical reagent, is mixed and remixed in the three gravity mixing'units 28, 38, 39, 46, 47, 48, giving an extremely uniform distribution of the nitrogen or other chemical reagent which is applied to the solid. Further, the shutters 31 and 50, 51 are preferably operated alternately, the load being first accumulated in the upper unit. The shutters 31 are then opened whereby the material is all dropped simultaneously in the mixing operation as explained and transferred to the lower unit which, being empty, is closed to receive it. The shutters 31 are then closed. When the load from the upper unit has been transferred to the lower unit, the shutters 50, 51 are in turn opened by gravity, discharging the ma terial from the mixer by way of shaft 10. Shutters 50, 51 are then immediately closed to receive the subsequent load which is first accumulated in the upper unit. 7

While the operation described is the preferred operation, it will be understood that a fairly satisfactory result in the way of mixing the gaseous reagent and solid may be attained without the lower portion of the apparatus, i. e., the dry mixer.

I have thus described specifically and in detail a mixer for combining active nitrogen or j and moving other gaseous or liquid chemical reagent, with solid comminuted material, as phosphate, the description being specific and in detail, in order that the manner of constructing, operating, applying and using the invention may be fully understood; however, the specific terms herein are used descriptively rather than in a limiting sense, the scope of the invention being defined in the claims.

What I claim as new and desire to secure by Letters Patent is:

1. The method of mixing continuously a gaseous reagent and solid material which consists in injecting the normally gaseous reagent in liquid form into a chamber and moving the comminuted solid at high speed in an orbital path in said chamber, the reagent being directed into said path from points spaced along said path, discharging the comminuted solid thus treated from said chamber and subjecting it thereafter to further mixing steps whereby the variations in the strength of the mixture of reagent and comminuted solid are equalized, the gaseous reagent being confined in close contact with the comminuted solid throughout the mixing operation thus specified.

2. The method of mixing continuously a gaseous reagent and solid material which consists in injecting the normally gaseous reagent in liquid form into a chamber and moving the comminuted solid at high speed in an orbital path in said chamber, the reagent being directed into said path from points spaced along said path, discharging the comminuted solid thus treated from said chamber and subjecting it thereafter to further mixing steps whereby the variations in the strength of the mixture of reagent and comminuted solid are equalized, said further mixing steps consisting in accumulating in adjacent enclosures portions of the material discharged successively partially distributing them from one enclosure to the other, and discharging the accumulation simultaneously, the gaseous reagent being confined in close contact with the comminuted solid throughout the mixing operation thus specified.

3. The method of mixing continuously a gaseous reagent and solid material which consists in injecting the reagent in liquid form into a chamber the comminuted solid at high speed in an orbital path in said chamber, the reagent being directed into said path, removing the comminuted solid thus treated from said path and subjecting it thereafter to further mixing steps whereby the variations in the strength of the mixture of reagent and comminuted solid are equalized, said further mixing steps consisting in accumulating in adjacent areas portions of the material dropped successively partially distributing them from one area to the other, dropping the accumulation simultaneously, and turning the portions at the centre outwardly and the portions at the periphery inwardly, the gaseous reagent being confined in close contact with the comrninuted solid throughout the mixing operation thus specified.

a. The method of mixing gaseous reagent and solid material which consists in spraying the reagent into a chamber and moving the comminuted solid at high speed in an orbital path in said chamber, the reagent being directed into said path, removing the comminuted solid thus treated from said path and subjecting it thereafter to further mixing steps whereby the variations in the strength of the mixture of reagent and comminuted solid are equalized; said further mixing steps consisting in accumulating in adjacent areas portions of the material dropped successively partially distributing them from one said area to the other, dropping the accumulation simultaneously, turning the portions at the center outwardly and the portions at the periphery inwardly, and further mixing the solid comminu'ted materials thus treated.

5. An apparatus for the continuous or gaseous mixing of gaseous or liquid material and comminuted solid which consists of a rotary beater having conveyor blades and fan blades projecting beyond the conveyor blades, a chamber for enclosing the same, nozzles arranged about the periphery of the chamber directed inwardly for injecting the gaseous or liquid material into the path of the beater, a mixer for comminuted solids below said beater and connected to the said chamber whereby the mixture of the gaseous or liquid material with the solid comminuted material is projected into the said latter mixer and further equalized.

6. The combination in an apparatus for the continuous mixing of gaseous or liquid material with comminuted solid which consists of a rotary conveyor for the comminuted solid, a beater chamber receiving the solid from the conveyor, a beater in said chamber having fan blades projecting beyond the beater, means for injecting gaseous or liquid material into the path of the beater, a gravity mixer chamber connected tothe beater chamber by a relatively large passage, permitting the circulation caused by the fan to pass the material into the said latter mixer chamber and to draw a portion of it out of the mixer chamber, the solid material being dropped in the mixer.

'7. The combination in an apparatus for the continuous mixing of gaseous or liquid reagent with comminuted solid which consists of a conveyor for the comminuted solid, a beater chamber receiving the solid from the conveyor, a beater in said chamber having fan blades inclined backwardly as to the direction of rotation, means for injecting gaseous or liquid reagent into the path of the beater, a mixer chamber connected to the beater chamber by a relatively large passage permitting the circulation caused by the fan to pass the material into said mixer chamber and draw a portion of its out of the mixer chamber, the dry material being includes a plurality of mixing units.

8. The combination in an apparatus for mixing gaseous or liquid material with comminuted so id which consists of a rotary conveyor for the comminuted solid, a solid from the conveyor, a beater in said chainoer having fan blades projecting from the beater and inclined backwardly as to the direction of rotation, means for injecting gaseous or liquid reagent into the path of the beater, a mixer connected to the beater chamber by a relatively large passage permitting the circulation caused by the fan to pass the material into said latter mixer and draw a portion of it out of the chamber, the dry material being includes a plurality of gravity mixing units, which consist of adjacent containers spaced apart and open at the top and bottom and shutters at the bottom of said containers permitting the material to accumulate successively in said containers and to overflow from one to the other, such accumulations being dropped simultaneously by the shutters.

9. The combination in an apparatus for mixing gaseous or liquid'reagent with comminuted solid deposited in the mixer which beater chamber receiving the dropped in. the mixer, which which consists of a rotary conveyor for the comminuted solid, a heater chamber receiving the solid from the conveyor, a beater in said chamber having fan blades projecting from the heater and inclined backwardly as to the direction of rota tion, means for injecting gaseous or liquid reagent into the path of ti e beater, a gravity mixer cham ber connected to the beater chamber by a relatively large passage permitting the circulation caused by the fan to pass the material into said latter mixer and draw a portion of it out of the chamber, the dry material being dropped in the mixer, which includes a plurality of gravity mixing units, one said unit consisting of concentric containers spaced apart and open at the top and bottom, and shutters at the bottom of said containers, permitting the material to accumulate successively in said containers and to overflow from one to the other, such accumulations being dropped simultaneously by the shutters, and means below said shutters for turning the material at the center outwardly and for turning the material at th outside inwardly.

10. The combination in an apparatus for mixing gaseous or liquid reagent with comminuted solid which consists of a rotary conveyor for the commiiiuted solid, a beater chamber receiving the solid from the conveyor, a beater in said chamber having fan blades, means for injecting gaseous or liquid reagent into the path of the beater, a gravity mix r chamber connected to the beater chamber by a relatively large passage permitting the circulation caused by the fan to pass the material unto said latter mixer and draw a portion of it out of the chamber, the dry material being dropped in the mixer, which contains a mixing unit, which consists of adjacent containers spaced apart and open at the top and bottom and shutters for closing the bottom of said containers, permitting the material to accumulate successively in said containers and overflow from one to the other, such accumulations being dropped simultaneously by the shutters, and a bypass connecting the space on the two sides of the shutters to equalize the gas pressure in the gravity mixer, said chamber and said gravity mixer being closed throughout to prevent the escape of the gases or fumes of the reagent prior to the discharge of the mixture at the end of the mixing operation.

11. In a machine for the continuous mixing of gaseous or liquid reagent with comminuted solid, a beater having conveyor blades and fan blades projecting outwardly therefrom, a cham-.

ber enclosing the same, means for feeding comminuted solids to the center of the chamber, means for feeding the reagent into the path of the feeder and a mixer for solid comminuted material connected to the beater chamber to receive the solid material from the beater and complete the mixing operation.

12. In a machine for mixing gaseous or liqm'd reagent with comminuted solid, a rotary beater, a conveyor for feeding comminuted solid to the beater near the center, means for feeding the reagent into the path of the beater, a casing for the beater of double conical form the beater being located at the zone of greatest diameter of said casing and a mixer for comminuted solid material connected to said casing to receive the comminuted material treated with the reagent projected therefrom and to further equalize and complete the mixing operation.

13. In a machine for mixing gaseous or liquid reagent with comininuted solid, a rotary beater, a conveyor for feeding the comminuted solid to the beater near the center, means for feeding the reagent into the path of the beater, a casing for the beater having its walls inclined and otherwise formed to prevent pocketing of gases, said beater being located at the point of greatest diameter of said casing, which conforms closely at this point to the path of the outer portion of the beater and a mixer for comminuted solid material connected to said casing to receive the comminuted material treated with the reagent and projected therefrom and to further equalize and complete the mixing operation, said mixer for the comminuted solid material having portions of its walls inclined and being otherwise formed to prevent pocketing of the materials.

14. In a continuously operating machine for the dry mixing of gaseous or liquid reagent with comminuted solid, a beater having conveyor blades and fan blades projectin outwardly therefrom, a chamber enclosing the same, means for feeding comminuted solids to the center of the chamber, means for feeding reagent to the chamher, the apparatus including a gastight container enclosing the beater having surfaces disposed toward the beater causing the comminuted material to return to the path of the beater when it is thrown outwardly therefrom whereby the beater serves to keep the coinminuted material in suspension in the gas throughout the beating.

operation, and means for discharging the comminuted solid from the container.

15. In a machine for continuous mixing of gaseous or liquid reagent with comminuted solid, a beater having conveyor blades and fan blades projecting outwardly therefrom, a chamber enclosing the same, means for feeding gaseous reagent to the chamber and means for feeding coinminuted solids to the center of the chamber, a mixer for solid comminuted material connected to the beater chamber to receive the solid material from the beater and complete the mixing operation, keeping the comminuted material constantly in motion and in suspension in an atmosphere of the gaseous reagent, the chamber being substantially gastight to prevent the escape of the gaseous reagent.

16. The method of mixing anhydrous ammonia with comminuted phosphate rock and similar solids in the manufacture of fertilizer which consists in retaining the reagent in liquid form under pressure in excess of atmosphere and injecting the reagent into a chamber where it becomes gasifled by the release of the pressure, moving the comminuted solid at high speed in an orbital path in said chamber, the reagent being directed into said path and continuing the mixing operation, keeping the comminuted solid constantly in circulation in contact with the gaseous reagent until the gaseous reagent is completely absorbed by the solid, the chamber being tightly closed so as to prevent discharge of the reagent except as combined with the solid, and further mixing the dry material whereby any variation in the strength of the mixture of the reagent and the comminuted solid is equalized.

AUGUSTUS J. SACKETT.

Images