US2144384A

US2144384A - Soft stone eliminator

Info

Publication number: US2144384A
Application number: US704159A
Authority: US
Inventors: Mikan Victor
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-12-27
Filing date: 1933-12-27
Publication date: 1939-01-17
Anticipated expiration: 1956-01-17

Description

Jan. 17, 1939. MIKAN 2,144,384

SOFT STONE ELIMINATOR Filed Dec. 27, 1933 2 Sheets-Sheef; 1

o o O O 4 We for Ni/ran Jan. 17, 1939.

v. MIKAN SOFT STONE ELIMINATIOR 2 Sheets-Sheet 2 Filed Dec. 27, 1953 Vie for Mike/7 Patented Jan. 17, 1939 UNITED STATES PATENT OFFICE sor'r STONE ELIMINATOR' Victor Mil ran, Durand, Mich. V ApplicationDecember 27, 1933, Serial No. 704,156

3 Claims.

This invention relates to a machine and to a method for the reduction or disintegration of soft particles present in a mixture of soft and hard particles to permit the separation of onemechanical eliminators are built on the principle of throwing the individual stones against a wall or plate with sufficient force to cause the soft stone particles to break. In the theory and practice this design is incorrect, and it vis usually found that quite ahigh percentage of good stone is reduced and rendered unfit. The reason is, that the kinetic energy, in the'thus thrown stone, is a function of its mass, and the hard stone being heavier than the .soft stone, 9. large portion of the good or hard stone is thrown with sufficient force to reduce the same to an objectionable extent during the reducing of the soft stone. A further undesirable feature of these machines is that the impact which the individual particles receive is wholly uncontrolled. A still further undesirable feature is that due to the inherent design of the machines of this type, replacements of wearing parts are frequent and usually quite costly.

It is an object of ,this invention to. eliminate 7 the above undesirable features and to provide a machine which will readily and effectively elim- A still further object of this invention is to provide anew method of eliminating soft stone from gravel, which consists in subjecting the gravelto. a series of impacts of controlled intensity'to break the soft stone and to render the gravel suitable. for separating the 'broken'soft (cl. act-#94) stone from the hard stone by screening or the like.

These and other objects will be apparent when taken with the specification and accompanying drawings in which,

Fig. 1 is a perspective view of Fig. 2 is a side elevation,

Fig. 3 is a vertical section taken on theline III-III of Fig. l,

the invention,

Fig. 4 is a vertical section taken on line IV--IV of Fig. 2, and

Fig. 5 is a vertical section taken on the central axis of an impact bar.

The soft stone eliminator I is mounted on a supporting frame 2. The principle element of the invention is the rotor 3 which consists of impact bars 4, a mounting plate 5 and an annular plate ii. The mounting plate 5 is sup,-

ported and attached to a flanged hub I which plates into which they are fitted, as at l2. The

impact bars 4 are prevented from rotating on their own axes by lugs l3 fitting in small bores M. It has been found that there is a great amount. of wear on the inside faces of the impact bars 4 and practically none on the outside faces. The impact bars 4 are therefore designed as shown in Fig. 4 heavily built up on-the wearing side. To the inside of the mounting plate-.5 is attached a deflecting ring if: to deflect the gravel which enters the machine ,through'the hopper IE to the impact bars 4.

The rotor 3 is enclosed in front by plates I1,

and i8 and in the rear by plates Hand 20. Between the front andrear plates the casing'casting 22 is mounted by means of bolts M. The

casing casting 22 surrounds substantially the en-' tire periphery of the rotor 3 and with the plates l1 and 20 defines the exit chute 23 through which 'treated gravel is discharged onto a sizing screen not shown, or into any suitable container. The plates l1 and IB are constructed with a suitable opening to permit the reception and attachment of the hopper l6.

' The operation is as follows: Gravel containing soft stone is introduced to the. machine through the hopper I6. It strikes the deflecting ring [5 and is deflected downwardly to the impact bars 4, which" are rotating with the rotor 3, and the individual particles are struck one or more blows. The characteristics of the hard and soft stone in the gravel will vary with each gravel pit and for this reason it is necessary to regulate the peripheral speed of the rotor until a satisfactory reduction in soft stone is accomplished. By reg ulating the rate of rotation of the rotor the intensity of the impact of the bars 4 may be controlled to the point that substantially all the soft stone is reduced without breaking up the good or hard stone to any objectionable amount. In'

, some cases it may-even be desired to increase the speed of the rotor 3 to the point where the hard stone is reduced to a controlled degree to improve its characteristics for certain types of construction work. In practice it has been found that with most grades of gravel rotation of a 36 inch rotor between 475 to 600 revolutions per minute will result irr'the reduction of soft stone in the gravel to less than 1% without objectionable reduction of good or hard stone. Following impact by the bars 4, the gravel is carried by its own velocity and in some cases by additional impacts out against the casing casting 22. From there it is carried around the rotor 3, bearing heavily, due to centrifugal force'against the casingcasting 22 and is discharged unharmed out of the exit chute 23. -In the event that a soft piece of stone drops through the hopper l6 into the machine it is struck one or more blows by the impact bars 4. Usually theflrst blow breaks the soft stone into many smaller pieces, and these pieces are carried through in the same manner as the good stone. The blows of the impact bars 4 and the abrasive action of the casing casting 22 on the soft stone particles as they are carried around between the casing casting 22 and the rotor 3, together with the scrubbing action they receive from the other pieces of stone in the machine disintegrates or reduces them to.

stantiated. The particles appearto be given sev- I eral impacts before they leave the confines of the rotor and casing casting. While it is believed that the particles rebound to a certain extent, between the rotor 3 and the casin this theory is not wholly borne o by the appearance of the machine after continued use, for there is practically no wear on the outsides of the impact bars 4. It has been found that the best results are obtained when water is admitted to the machine with the gravel, the water reducing wear and assisting in the removal of broken down or disintegrated soft stone.

A novel and important feature of this invention is the operation of the deflecting ring IS in conjunction with the impact bars 4. When the dcfiecting ring is new, its shape causes it to deflect 4 the gravel to a point on the impact bars 4 near casting 22,

the gravel to a point on the impact bars nearer life of the impact bars is considerably lengthened. That my improved method of disintegrating the soft stone can. be carried out in apparatus other than the one heretofore described is fully'appreciated. The essential features reside in directing a stream of gravel containing both hard and soft stone with relatively slight velocity into a region where both the hard and soft stones are acted upon by impact members or equivalent means having considerable velocity with equal intensity; the kinetic energy of the impact members being so controlled as to result substantially only in the disintegration of the soft stone without breakage or reduction of thehard or good stone beyond an objectionable amount. In this respect my method varies from other methods employed in similarv machines in which the kinetic energy of the gravel itself is utilized to disintegrate the soft stone.

By gravel, small stones having a diameter ofv not greater than. three inches, is meant. The soft stone referred to may be either separate or attached to hard or good stone, and'includes, for

-to the operation and characteristics of my. ma-

chine and improved method of removing soft stone from gravel apply equally as well in the reduction of soft particles in other mixtures where ,it is desired to so reduce the soft particles to permit separation from hard particles by screening or equivalent methods. For example, my improved apparatus and method has application in the reduction of rock saltto permit the hard shale present to be separate from the salt by screening. Also in the refining of gypsum being softer than the dolomite, the latter may be separated by screening upon the reduction of the softer particles of gypsum.

In the claims the referenceto gravel and the like is used to designate generally mixtures of hard and soft particles including besides gravel other mixtures having similar characteristics including' those specifically mentioned in the foregoing paragraph. I

While the specification discloses a single embodiment of the invention it is apparent that it is merely illustrative of the broad principles in- V.olved and it is not intended that it be limited except by the scope of the following claims.

I claim:

1. A method of processing gravel used asan aggregate in concrete construction to reduce the soft stone commingled with the gravel to a" fineness permitting separation by screening or washing comprising, directing a stream of gravel downwardly to flow by gravity, subjecting substantially all the particles in the flowing stream of gravel to impact blows of substantially uniform intensityapplied transversely across the line of flow by moving a series of impact members in single file in the same direction across the line of flow, regulating the intensity of such blows so that the force of such blows will be sufficient to disintegrate soft particles without appreciable fracturing of hard particles, further treating the gravel and soft stone by said impact members to effect a rubbing and abrasive action thereon and simultaneously discharging both hard and soft particles. x

2. 'I'he method of processing gravel for use as an aggregate in concrete construction which gravel consists of hard stone pieces capable of bearing load forces encountered in use and soft stone pieces likely to break down under load forces of use comprising, directing a stream of such gravel to travel in a predetermined path and at substantially uniform speed, and subjecting substantiallyall of the stone pieces in the stream of gravel to impact blows of substantially uniform intensity applied transversely across the line of flow by moving a series of impact members in single file in the same direction across the line of flow and regulating the intensity of such blows so that the force of the blows is sufficient to disintegrate soft stone pieces without appreciable fracture of hard stone pieces.

3. The method ofprocessing gravel for use as .an aggregate in concrete construction which gravel consists of hard stone pieces capable of bearing load forces encountered in use and soft stone pieces likely to break down under load forces of use comprising, directing a stream of such gravel to travel in a predetermined path and at substantially uniform speed, subjecting substantially all of the stone pieces in the stream of gravel to impact blows of substantially uniform intensity applied. transversely across the line of flow by moving a series of impact members in single 'flle in the same direction across the line of flow and regulating theintensity of such blows so that the force of the blows is sufficient to disintegrate soft stone'pieces without appreciable fracture of hard stone pieces, and confining the material following the application of the impact blows to travel with the unfractured hard stone pieces and the fractured soft stone particles intermixed and discharging the same through an outlet.

vicroa MIKAN.