US1458387A - Process of treating concrete aggregate - Google Patents

Description

June 112, H928. 11,458,387 c. L. BOURNE PROCESS OF TREATING CONCRETE AGGREGATE Filed M y 17 1920 Patented June 12, 1923.

arren stares laiifidiiti CHARLES LUTHER BOURNE, or ivrrnnnaroms, MINNESOTA.

PROCESS OF TREATING CONCRETE AGGREGATE.

Application filed May 1"], 1920. Serial No. 381,925.

T 0 aZZ whom it may concern:

Be it known that 1, CHARLES LUTHER Bonnnn, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improven'ients in Processes of Treating Concrete Aggregate; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same. 1

My invention has for its object to provide an improved process of removing the softer or less tough particles from the harder or tough particles of substances, such as gravel; and to such ends, generally stated, the invention consists of the novel treatment or steps of manipulation hereinafter described and defined in the claims.

Especially, the invention is directed to means for insuring better aggregate for concrete by removing from gravel all of the softer or less tough particles, such as soft rock, shale, and dried clay or dirt.

My improved process consists in projecting the uncleaned aggregate, containing all of the harder and softer particles, against a hard surface at such high velocity, or otherwise subjecting the same to an impact so that the impact produced will finely break up or pulverize all of the relatively soft or less tough undesirable substances or in other words, the substances having a co-efficient of hardness below a certain standard, such as soft rock, shale, dried clay or dirt, but will leave intact, or, in any event, not break up to any considerable extent, nor pulverize the hard or tough substances or thus having a co-eflicient of hardness above a certain standard. This step of the process reduces the aggregate to such a condition that all of the soft or less tough substances can be re-v moved and separated from the harder or tougher substances by a screening action, or otherwise, as by washing orair blast. The extent to which the softer or less tough substances will be finely broken up or pulverized may be varied, first by varying the force of each impact, and second, by varying the number of impacts or repetitions.

The harder or tougher substances thus left in the cleaned aggregate will, of course, produce the highest possible grade of concrete, such as required for pavements, or any concrete work that is subject to high stresses.

One of the chief causes of rapid Wear or dis.-

integration of concrete pavements is due to wearing away by the action of abrasion or the weather, of exposed relatively soft or less tough particles. v

The aggregate may be projected, as stated,

in different Ways, as, for example, by ceni trifugal force, by gravity, or bydirect force.

One form of the. apparatus suitable for performing the process above described is illustrated in the accompanying drawings wherein like characters lndicate like throughout the several views.

Referring to the drawings:

Fig. 1 is a vertical section illustrating the apparatus; and i Fig. 2 is a transverse section taken on the line 2-2 of Fig.1. I

The numeral 3 indicates a larger outer slightly inclined drum, preferably, of sheet metal. This drum, at its lower portion, is

parts shown as provided with two axially spaced spider-like heads that are rotatably mounted on an inclined shaft 5, which latter, at itslower end, is journaled in a fixed bearing pedestal 6, and at its upper end is journaled to a fixed bearing pedestal 7. Atits upper or receiving end, the outer drum 3 isirigidly secured to an inwardly projected deflecting cone 8, which, inturn, is rigidly secured to the arms of a spider-like head 9 carried by a sleeve 10 rotatively mounted on the shaft 5. Approximately-in line with the defleeting cone 8, the drum 3 is shownas provided with axially spaced outstanding flanges 11 that afford an annular channel into which the lower end of a fixed hopper 12 projects for the delivery of the aggregate into said drum 3 through closely adjacent circumferentially spaced ports 13.

VVoi-king within the outer drum 3 and so cured to and carried by the shaft 5 is an inner drum 14 that extends through the contracted portion of the deflecting cone 8, at its upper end, but at its lower end, terminates short of the inner of the two headset. This inner drum 14; is provided with circumfereir tially spaced longitudinally extended heavy hard metal. or steel impact cleats 15. The outer drum 3, on its inner surface, is provided with longitudinally extended circumferentially spaced similar impactcleats 16. At intervals between said cleats 16, the drum 3 is provided with internal lifting flights. 17. That portion of the outer drum 3 that is between the heads 4, is shown as perforated so lli) as to I afford-Kan larger pulley 27 which, as

' into the receiving end of the a it drum '14.

c theimpacting aiiiiular screen 18 that will deliver into a receiving hopper 19. The numeral 20 At its upper end, the shaft provided with a pulley 23that is driven through a belt adapted to lb'edriv'en. at variable speed under the vcontrol of-a rheostat 26.

The sleeve 10 is provided with a relatively shown, v is. driven through a belt% from another electricmotor--29- that is adapted to be driven at varispeed of the respective motors. However, it

will be understood thatv this apparatus is nly one ,of the many forms that may, be

used for'p'erforming-the process.

Describin the apparatus illustratedin its use, for performingtli-eprocess,-it willjfirst be noted that the" aggregate, will be delivered outer drurn and, onto the receiving end of, the. inner By the rotation of, said inner druin at highfsjpeed, the-aggregate will be thrown o'utward by centrifugal force against plates 16- ofrthe outer drum and the'require'd impacts will be produced. These impacts will be repeated over and over a ain as the a t re rate' r'aduall works D t) D b downw rd to the delivery. or lower end of the inner drum. The aggregate thrown against the inner surface of the outer drum will, by. the lifting flights '17, be carried upi i walr'd over [and over again, and dropped'by centrifugal force onto the cleaned surface- 1 of the inner drum, thus the aggregate will-be-sub'ject to the repetitions of the pacts already noted.

The beveled faces ofthe cleats 16 also assist in returning theaggregate over and over again onto the cleated surface of the: inner dru'rn'yand as the aggregate falls back indicates a non-rotary head that isfixed to the'ljr'aelieflG' and closes the lower ,end of the drum 3-, except for a discharge passage 21 that delivers into discharge spout 22.

against said inner drum, the cleats 15, striking the same at high velocity, will also produce impactswhich assist in breaking up theso-fter or less tough substances.

After the aggregate has been treated, as described, it is" delivered onto the rotating annular screen 18, and, under rotation thereof, the pulverized orfinely broken particles will be sifted out and intothe hopper 19, while the harder and larger particles will be carried on andfdelivered into the discharge spout 22. Y

may be varied by varying the inclination of the drums, it being, of coarse, understood that the greater the inclination of the drums,

the more rapid will be the progress of the aggregate through the outer drum, and hence, theless the number of impacts; the crushing action may be; varied'by varying the speed of rotation of the innerdra n However, as already indicated, the process may be performed by various other forms of apparat' What I claim is;

1. They process of treating. aggregate material. compris ng gravel or other rock parwith softer particles, such as soft rock, shale, clay, dirt andthelike', which consists in subjecting said material? to ticles associated repeated impacts between relatively moving surfaces, regulatingsuch impacts in number and force so asto break up part cles having The number of impacts us,or by any other suitable means; I,

a vco-efficient of hardness less than a certain standard but not to break up the particles having a co-efficient of hardness greater than said standard, anddthen separating the broken-up particles from the unbroken particles to produce an aggregate material new ing a standardof hardness suitable for cori- I crete, v 2. The process of treating an: aggregate material comprising, gravel associated vwith r ds t cl y,

P cle o .sqfi t hei and other soft particles, which consists n projecting said inaterial'by centrifugal force and producing impact-s thereon by. moving surfaces so regulating I said impacts as to break up the particles of soft rock,',shale,

clayand other so ft material, bueaettq A break up thehar'd particles, then separating the broken-up particles from the hard'particles to produce an aggregate of hard particles suitable for concrete. y l

In testimony whereof IfifiiX s'i J tters; CHARLES LUTHER BOU' NE.

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