US1577218A - Method and means of mixing concrete - Google Patents

Description

March 16 ,1926. r

M. FLETCHER METHOD AND MEANS OF MIXING CONCRETE.

Filed July l4 1925 2 Sheets-Sheet 1 INVENTOR Maiihews'fieicller 'ATTo EY March 16 192 6.-

- 1 ,577,218 M. FLETCHER METHOD AND MEANS OF MIXING CONCRETE Filed July 14, 1925 2 Sheets-Sheet 2 INVENTOR Mazihewsilei'cken 9 ATTORNEY Patented Mar. 16, 1926.

uN TED srA'rss 'MA 'rrrnws FLETCHER, or INDIAN-seems, INDIANA;

' METHOD AND MEANS OF MIXING CON CRETE Application filed July 14, 1925. Serial No. 43,631.

To all whom it may concern:

' Be it known that I, MATTHEWS FLn'roHnn, a citizen of the United States, residing at lndianapolis,-in the county of Marion and State of Indiana, have'invented certain new and-useful Improvements in Methods and Means of Mixing Concrete, of which the fol- "lowing is a specification.

My invention relates to a method of mixing concrete and a mechanism for carrying out such-method and it is an object thereof to provide a device in which the process of mixing shall be a rapid and violent stirring action applied to a rapid and continuous succession of small batches of materials in place of the customary process of mixing in which slow tumbling and stirring action is applied to j a slow repetition of comparatively large batches of materials.

The common method of producing concrete by machine is to load 'a batch of ingredients into a slowly revolving cylinder or drum'where the mass is mixed by tumbling, discharged, and the process'lrepeated with another batch; a The drum must' revolve slowly inorder to prevent simply whirling the mass without mixing, and consequently the time required to thoroughly mix a batch is practically thesame for large and small machines. Tl1' advantages of 7 rapid and violent agitation to secure intimate mixing and adhesion of cement are well known, but heretofore these advantages have not been obtained generally in'a portable machine of commercial capacity on account of the struc tural and mechanical difficulties attending the rapid and violent agitation of the heavy semi-liquid mixture of concrete in. large quantities. My method contemplates overcoming these diflicultiesby greatly reducing the size of the batch or unit of production, assembling a rapid succession or continuation'of batches, and rapidly mixing them in and dischargingthem from a small machine of violent action.

Among other advantages of 111y-1netliod and device may be mentioned the fact that they produce an intimate mixing and ad- 5 hesion of cement to other particles with consequent density and strength in the ultimate concrete, the fact that they provide for accurate control of the proportions of the materials entering into themixture, the .fact

- that they-provide for the conimingling of the solid materials in predetermined constant,- proportion before entering the final mixin process, and the fact that they provide for the production of concrete mixture in a practically uninterrupted flow with consequent-large average output per unit of time. Q r V Referring to the accompanying drawings which are made a part hereof and on which similar reference characters indicate similar parts, I

Figure 1 is a plan of a mechanism constituting a preferred embodiment of my invention,

,. Figure 2, a side elevation partly in section, Figure 3, a section online 33 of Fig.1, f Figure 4, a detailof a part as seen from the right in Figure. 3,, 1

Figure 5, a section at right angles to Fig with modifications of certain/parts, and a Figure 6, a fragmentary section on linev 6-6 0f Figure 5. I V In the drawings reference characters 10, 11 and 12 indicate separate bins for different solid ingredients, said bins being indicated in the present embodiment of the invention and for the present purpose, as containing respectively, sand, gravel and cement.

Each bin is shown as having an outletat its lower end as indicated at 13 by'means of which the material in the corresponding bin is'permitted to flow down upon the'upper run of a conveyor belt 14: in a'continuous stream, and this material forms a continuous ridge or stream on the belt in the channel between two of a series of partitions or walls '15 supported above and extending along thebeltl l. Each of the channcls'betweenpairsof partitions 15 is provided with a gate 16 adjustable vertically and held in position by any suitable means, which gates serve to limit adjust-ably the 'amount of material which will move forward with the coin veyor; in the respective channels, thereby providing a means'of proportioning the materials in any ratio desired. The and arrangement of bins,.the inclination of the conveyor, the distance the, conveyor travels and all such minor details may be varied to suit particular circumstances or preferences.

Another conveyor 1'7, which may convennumber iently be referred to as a sweeper, is provided adjacent to the forward end of the conveyor 14; and this secondary conveyor or sweeper provided with brushes or blades 18 at suitable intervals in its length and so placed and guided that the brushcsor blades or similar suitaldc devices 18 will travel in a constant path across the upper run of the primary conveyor lat and along a trough 20 (Fig. 3) extending beyond its edge, thereby carrying batches of commingled materials oil the primary ctmveyor, through the trough 9t) and into the hopper 21. In this way, it will be seen that the brushes take a cross section of each stream of material and so carry suitable increments of all materials which make up the mixture. The sweeper l7 is regarded as carrying successive small batches of commingled materials to hopper 21 where they may he allowed to accumulate in a mass the ingredients of which are nearly uniformly proportioned throughout. Or it might be regarded as operated step by step and provided with more positive batchconveying means whereljiy the successive small batches would be more or less independently fed to a mixing device or series of devices. A pipe 22 with a valve .23 provides a means of adding water to the materials in the hopper 21.

A mixing device suitable to accomplish the final mixing oil the commingled solids with *ater or other suitable liquid islocated beneath an opening; in the bottom of hopper 21. My mixing device consists of a vertical passage or clunnber formed by a stationary casing 2a which forms with the hopper a device shaped approximately like an hourglass and is oi? circular cross section. In this chamber an agitator 25 is rapidly revolved by means oi. a. shaft which preferably is concentric with the vertical axis. of the chamber and which may enter the chamber from above through the opening in the bottom of hopper 91 without the necessity of providing a striding-box, all as shown in Figs. 2, 3 and The chamber is open at the top to receive the mass or batches of n'iaterials from the hopper and it extends downward to an open bowlor pan 27 provided to catch the mixture and thereby retard its rate of flow tl'irough the mixing chamber above in order that it may be re tained long enough to be subjected to thorough stirring by the agitator 5. The pan 2T provided with an overflow spout 28 in the side or rin'i, or means may be provided for removing the mixture at the desired rate by intermittently tilting the pan or by undermining by means of a conveyor 30 which may operate on the mass through an opening in the pan 2? at the bottom of the mixing; clunnber as shown by Fig. The cross sectional area of the mixing chamber may be constant throughout its length as in astraight tube or it may be *aried, preterably increasing from top to bottom as shown. The agitator 25 consists of a series of blades, paddles, or irregularities 29 which can be rapidly revolved about a vertical axis concentric with the axis of the chamber. The surfaces ot the. blades may be warped or formed into the shape of a screw to exert a vertical pressure upon the mixture in addition to the stirring: action, and such a screw may extend up into the hopper 21 to provide a positive means of feeding the mass into the mixer. all as shown.

In the use of my device the materials are placed in separate hopper bills from which they pass to separate channels or chutes the bottoms of which are formed by a moving conveyor belt apron or platform which drags or pushes the materials through the channels and under grates or scrapers which areadjustcd to limit the quantities that will emerge in constant proportion and will fol low on the conveyor in continuously formed parallel streams.

The parallel streams of materials in constant proportion are carried forward. by the conveyor from which a cross section or batch of them is swept or pushed at. intervals by a series of flexible or pliant brushes or blades moved by a. belt or wheel revolving trainsversely to the direction of the streams, and the batches thus formed are swept or pushed oil of the conveyor and into a hopper.

The batches of solid ingredients in predeterinined; proportion enter either intermittently: or contimiously into the hopper 21L into which the liquid ingredient (as water) also flows, and from which the mass flows through a mixing chamber 24; where it is violently agitated and mixed as it flows by a series of rapidly revolving blades preferably revolving on a vertical axis concentric with the vertical axis of the mixing chamher. The mixture is kept from simply falling through the chanlber, with consequent sepamtion ot the particles, by the pan or bowl 2? which being placed beneath the botton'i opening of the mixing chamber tends to support the mixture in the chamber and retards its rate of flow enough to allow time for proper mixing. The pressure exerted by the weight of incoming batches, which n'essure may be increased by the downward pressure exerted by the screw-slmped agitator. causes the finished mixture to flow or (to use a word that recently has come into general use to accurately describe the action) to slmnyf over the edge or brim ot the pan at the overflow spout. In place: of the slump process of discharging the finished mixtin'e, a more positive means of discharging by umlermining the mixture, or by intermittent- 1y tilting the pan may be provided and suit ably synchronized. The arrangement of an agitator revolvingon an axis concentric with the vertical axis oi? a mixing chamber of receiving parallel streams for circular horizontal section allows of a very rapid rate of rotation. of the agitator Without piling up the mixture .to one side (as occurs Where an agitator is revolved rapidly 011a horizontal axis) and consequently the materials can be subjected to very forceful stirring tvhich causes the particles to collide with and impinge upon each-other with great violence and thereby to tend to,

each other and K to become thoroughly and intimately mixed in a very short time. The screw-shaped agitator and the flared? chamber provide additional means by which even stiff mixtures (that is, mixtures containing little or no excess water) may be forced through the mixing process. lhus is produced an intimate mixa ing and adhesion of cement with consequent density and strength in the ultimate concrete.

It will be obvious to those skilled in the adhere to art that various changes may be made in my device without departing from the splrit of the invention and therefore I do not limit myself to what is shown in the drawings and described in the specification but only as indicated in the appended claims.

Having thus fully described my said in vention, What I claim as new and desire to secure by Letters Patent, is t 1. A methodof mixing concrete Which consists in simultaneously. and continuously moving sundry ingredients in small parallel streams, disposed'laterally with relation to each other, and moving forward portions of the mass transversely of the path of movement of the streams to mix and discharge the same, substantially as set forth.

2. A, continuous process of mixing concrete or the like by producingcontinuous slowly moving parallel streams of different solid ingredients, and simultaneously hori Zontally and transversely ,mixing and feeding cross sectional increments of each stream into a mixing chamber, substantially as set forthQ i 3. The combination in a concrete mixing machine of a hopper having a plurality 'of' partitions forming a plurality of bins, and conveyor disposed beneath said hopper for of solid material of different character therefro-i'n, substantially as set forth.

l. lhc combination in a concrete mixing machine of a hopper having a plurality of partitions forming a plurality of bins, a conveyor disposed beneath said hopper receiving material of different character therefrom, means for feeding batches of material comprising a cross section of each stream simultaneously into a chamber, means for add ing Water thereto, and a rotary agitator in the chamber, substantially as set forth.

5. A concrete mixer as in claim 3, with parallel streams of solid independent means for adjusting the feed of solid material in each stream, substantially as set forth.

6. A concrete mixeras in claim 8, com prising a conveyor belt for supporting all of said streams of solid material, substantially as set forth.

7. A concrete mixer as in claim 3, comprising a conveyor belt for supporting all of saidstreams of solid material, and means keeping thep'arallel streams separate, substantially as set forth.

.8. A concrete mixer comprising a plurality of bins for solid r aterial, means for feeding material in parallel horizontal streams from the respective bins, guiding means for separating the streams from each other, gates for regulating the flow of ma terial in said streams, and a mixingchamher for receivin such material substantiall a conveyor movable transversely of the path of said streams, a mixing chamber to which said conveyor carries increments of material from each of said streams, means for supplying Waterto said mixing chamber, and

agitating means for the mixture, substantially as set forth. I

12. A concrete mixer comprising a con veyor for feeding solid material in parallel streams, a sweeper movable transversely of the path of said streams, brushes on the sweeper, a mixing chamber to Which said sweeper carries increments of material from each of said streams, means for supplying Water to said mixing chamber, and agitating means for the mixture, substantially as set forth.

13. A concrete mixer comprising means for feeding a parallel series of streams of solid material of different characteristics, a conveyor movable transversely of said feeding means, a trough in which said conveyor travels, amixing chamber at the farther end of the trough, means for feeding Water to the mixing chamber, and a rotary agitator in the mixing chamber, substantially "as set forth.

l layA. concrete mixer comprising means for f edingsolid material in pa "allel streams,

and conveying means movable transversely oi diii'rrnni solid ingrndiorig sinlnltnnuonsiy (hinnninn tho ingg'rndion'is Mid oonnnirnriing said dnnnnod ingredients by moving them in n sidrn'isn diroriioin snhsinni inily as set forth.

16. A method of mixing concrete (.(Hl'lPliS- in;- providing rontinnmish' moving streams of diiim'nnil solid in 'redimlts, sinlnitnnoonsiy ch'nnniinn; tho i11 11 innln and connningling' said dnnnnm ingredients by moving thnni in. n sidmviw direc-iion, nndi'hur :nrfter rapidly and violvniiy agitating the uonnningind ingroijhvnhts n passing: Them in conhicr with rapidly riiintinp; hhnins, Sililftiifitiielii) an 90tforth.

.17. A prmsrssi oi mining coi'ioroio corn ing: i nvding relntii'oiy sn'niii hatches of tho ingrndinnin in'io n hopper and downwnrdi paint an nprighi running wrrw conveyor,

.i i hopper at :11]. i'inneez, and discharging :1 produlorniinvd mmntit'v of thn mixture from the ho) 101' by :1 shnnjnn notion n 3011 the :1)-

L i r:

piicnfion of :i oorrespomiing amount of tho ingredients in the entrance 0nd of the hopper, snhstnniinll as sot forth.

18. A conveyor coinprisiing' :1 heh; hni 'ingy; :1 continuous row of brushes at one side and n sci-ins of spaced brushes extending; ncrons the bait from mid (:(niiinnons brushes, and :Riiifii'itllilY as set it'orih.

in winning whereof, I have hereunto Set my hnnd and seen] at Indi:innpolis, lfndinnn ihis 6th day of July, A. D. nineteen hundred n nd i \i'OlliiW-ihlfi.

MATIHEV S FLETGHE 1.

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