US2556486A

US2556486A - Sand treating apparatus

Info

Publication number: US2556486A
Application number: US68820A
Authority: US
Inventors: Benjamin A Smith
Original assignee: Co Bartlett & Snow Co
Current assignee: C O Bartlett & Snow Co; Co Bartlett & Snow Co
Priority date: 1949-01-03
Filing date: 1949-01-03
Publication date: 1951-06-12
Anticipated expiration: 1968-06-12

Description

June 12, 1951 B. A. SMITH SAND TREATING APPARATUS Filed Jan. 5, 1949 INVENTOR. fiEPUQP IJNA f/wul/ ATTOIZNEXS.

Patented June 12, 1951 UNITE SATES' "NT Fries"- SAND TREATING APPARATUS Benjamin A. Smith, Cleveland Ohio, assignor to The C. 0. Bartlett & Snow Company, Cleveland, Ohio, a corporation of Ohio Application January 3, 1949, Serial No. 68,820

prise sand. grains with predetermined quantities of bonding materials and water uniformly dis.- tributed therein for imparting the desired. properties for. the intended foundry purposes. Of

courseinpouring metal intothemold made from such sand mixtures or intreating the cores made from such mixtures, the-moisture thereinisdrive'n off by the 'heat and likewise-the bonding-material-- also tends to burn out and lose its efficiency when exposed to the high temperatures to'which ordi-- narily subjected whereas the sand itself is not adversely affected by such heat. Therefore,- the foundry sands can be rendered re-usable by restoring-the originalpercentages of bonding mate'- rial and water andintimatelyblendingsuch ingredients so as to coatthe individual-sandpar ticles and thus cause them to adhere to each other and leave voids for'the escape of gases.:- For so preparing foundry-sands, various fo'rmsof mixers have been devised heretofore but each are open to the objection that the sand introduced thereinto for treatment must be relatively cool,

thisoperation taking considerable time or else requiring additional elaborate and expensive equipment Prior attempts to incorporate' cool ing means in the mixer proper have proved' un' successful and costly to install with theresult that mixers such as those which are adapted to successively knead and agitate a batch of san'd' therein can only accommodate. pre cooled sands.

Accordingly, it is a primary object of this irrvention to provide a method and apparatuswhichi obviates the necessity of pre-cooling sand' being treated. Another object is to provide-a method and' apk" paratus for concurrently cooling and thoroughly mixing.v sand being treated,. such cooling incidentally effecting thorough aeration of the sand and .being accomplishediwith a minimumof 'additional apparatus and. within a. time? period no longer than theiusual-zmixingcycle.

Anotherobject is the-provision offa sandttreate ingrmethod" and apparatus in whichco'olingofith'e sandiis-z effectedxwhile'; :the sandiis whirledi and 21 thus thoroughly agitated, whereby a greater number of sand particles are subjected to the aforesaid influences and with a minimum quantity of coolant.

Still another object is the provision of a sand treating method and apparatus wherein the b10W- ing of a coolant through the sand in the region of agitationthereof further assures a more uni.-

formdistribution of the conditioning ingredients thereof.

Other objects and advantages will appear as" the description proceeds.

To the accomplishment of the foregoing" and" related ends, said invention, then; comprises the features hereinafter fully described and particularly pointedout in the claims, the following description and the annexed drawingsetting forth in-detail one'illustrative embodiment of the-in vention, this being indicative, however, ofbut one of the various ways in Which-the principle'of the invention may be employed.

In said annexed drawing:

Fig; 1 is a perspective View of one form of mix ing'apparatus Fig. 2 is a cross-sectionview-taken substantiale 1y along the plane indicated by'the line2--2; Fig.1;

Fig. 3 is a cross-section view taken substantially along the plane indicated by the line 3 3, Fig; 2';

Fig. 4 is a cross-section View taken substantiallyalong the plane indicated by'the line-4+4, Fig. 2;:and

Fig; 5 is. a cross-section view similar to Fig. 2"

except illustrating a power driven agitator.

Referring-now more particularly'to-the draw ing; the mixing apparatus exemplarilyxillustrated comprises'a base I supporting a bowlshapedcontainer' 2 for rotation in a horizontal planeab'out' its vertically disposed central axis;.the" driving:-

means forsaid container comprisingas 'forexampl'era motor 3 supported 'on'said base" below the" container and driving-the latter through intergearing 4'.

Within said containerandsupported on said:

base I for rotation about a horizontally disposed axis are vertically adjustablekneading-rolls 5-'ro"- tatably carried on a-shaft 5," having its opposite" endsfixedin'blocks' l, and said blocks-in turn being adjustable in vertical guidewaysformedin said base. as 'shown' with the peripheral faces thereof a de"' sired distance directly above the'an'nularhorizontally disposed area of th -bottom of 'saidcontain'er and substantially co-extensive with the radial'width of such area. Aswill hereinafter ap Said rolls 5 are-preferably cylindrical pear, the purpose of the rolls 5 is to knead and work bonding material into sand contained in said container and to break up the lumps in the sand. As evident, said rolls 5 will exert a combined squeezing and smearing action on the sand carried thereunder during rotation of said container. The clearance space between rolls 5 and container 2 may be varied as desired between zero and several inches.

Between said rolls 5 and likewise above the flat annular area of the container 2 is an agitator 8 formed with a vertically disposed tubular portion 9 and a star wheel is at the lower end of said portion 9. Said agitator is supported for rotation and limited vertical reciprocation on a tubular arm ll mounted on base I. The star wheel 10 has a bore l2 through the hub thereof and is formed with a plurality of radiating arms 3.

formed with tunnels or grooves IQ on the bottom side leading from such bore i2 to the ends of the tangentially extending tips l5 on said arms, said tips and arms being of such shape as to induce rotation of the agitator in a counter-clockwise direction as viewed in Fig. l in response to driving of the container 2 with the batch of sand therein in the same direction. The essential purposes of the agitator B are to improve the mixing characteristics of the apparatus, to break up lumps in the sand and prevent caking of the sand by the kneading action of rolls 5, and to clear the sand from the bottom of the container.

As best shown in Fig. 2, the tubular arm H and agitator 8 define a duct or passageway IE5 leading to the tips 15 of the agitator whereby a coolant (preferably air at room temperature) may be forced through said duct as from the end ll thereof and blown through the whirlingly agitated sand particles surrounding the agitator. Such blowing of coolant through the whirling sand not only effects a desired reduction in temperature of the hot sand which may be loaded into the apparatus by driving off any excess moisture but additionally aerates the sand to render the same fluffy and easy to ram into a mold, facilitates breaking up of the sand, and further tends to impel the agitator 8 in the same direction as caused by the movement of sand therepast whereby to still more effectively agitate and thus more thoroughly mix the sand.

On the other side of the container 2 is a scraper disk l8 which is mounted on said base I for free rotation about its central horizontally disposed axis and for swinging movement about a vertical axis from a position with its leading edge engaging the rim of the container and inwardly facing surface deflecting the sand being treated inwardly for kneading by the rolls 5 to a position with its leading edge spaced from the rim of the container whereby said rim and th other surface of the disk define a channel for collecting the thoroughly mixed and cooled sand and causing such sand to overflow the rim for discharge through any suitable chute into a receptacle disposed below said container.

It can now be seen that with hot sand and other necessary ingredients charged into container 2 to restore the respective percentages of the latter to a desired amount and thus condition the sand for subsequent use and with the container 2 driven counter-clockwise as shown, the rolls 5 will knead or squeeze the sand passing thereunder and the rotating agitator 8 will impart a rotary whirling action in the sand. At the same time room temperature air caused to flow under pressure through the passageway 16 will be blown through such whirling sand whereby to effectively reduce the temperature thereof and otherwise influence the sand in the partieslars already described. Thus, the air issuing from the tunnels It will cool the sand to a desired temperature and at the same time aerate the same and facilitate thorough agitation thereof. The coolant which, as indicated, may be room temperature air, is preferably forced through the passageway it by a turbine blower or pressure fan at a pressure less than 1 p. s. i., viz. about /2 p.:S. i.

To further facilitate thorough mixing and aeration of the sand being treated, the agitator may be power driven as shown in Fig. 5, said, agitator and drive therefor comprising a starwheel in, preferably the same as that previously I8 provided with.

described; a tubular portion lateral ports is adjacent its upper end and connected at its lower end to said star wheel IE, and

a conduit 2i] supporting said agitator for rotation. about a vertically disposed axis and forming: therewith an annular chamber 2! through which.

air or other coolant may flow to the ports i3 and thence through the tubular portion 18, and tunnels l4 in said star wheel during rotation of said agitator. Power driving of said agitator as herein exemplarily illustrated is effected by an electric motor 22 mounted on conduit 20 and meshing

bevel gears

23 and 24 respectively keyed to the drive shaft of said motor and to the upper end of the agitator. Said gears are enclosed within a housing 25 and thus protected from damage by the sand.

As apparent, when coolant is forced through the conduit 2s and through the agitator and while the motor 22 is energized, the apparatus as a whole will function in the manner indicated above except that because of the power driving of the agitator at a desired speed independent of the speed of rotation of the container 2, a more thorough mixing and aeration of the sand is made possible.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a sand treating apparatus, the combination of a rotary container for sand to be treated, a roll exerting pressure on the sand in said container, and a rotary agitator in said container circumferentially spaced from said roll and adapted to be buried in the sand, means supporting said agitator for rotation in the sand moving therepast to thus impart a rotary agitating motion to the sand, said agitator being provided with a coolant supply passage therein terminating near the bottom of the container so that air is discharged adjacent the bottom of the container for aerating the sand.

2. The method of treating sand comprising successively kneading and inducing a whirling agitating action in the kneaded sand, and during the agitation blowing a coolant through the sand from a point below the surface thereof and in the region of the whirling agitating action.

3. In a sand treating apparatus, the combination of a horizontally disposed bowl-shaped container for sand to be treated, a base supporting said container for rotation about its central vertical axis, means for rotating said container.

and the sand therein, a pair of circumferentially spaced kneading rolls having their central axes disposed in a horizontal plane and extending generally radially of said container and having their peripheral faces spaced a desired distance above the bottom of said container whereby to exert pressure on the sand in said container, means supporting said rolls for rotation about their central axes whereupon movement of the sand under said rolls during rotation of said container causes rotation of said rolls and consequent kneading and squeezing of the sand, an agitator in said container disposed between said rollers and adapted to be buried in the sand in said container, and means supporting said agitator for rotation about a vertically disposed axis, said agitator being provided with agitating elements in the sand operative to rotate said agitator responsive to movement of the sand therepast during rotation of said container and thus agitate the sand, said agitator further being provided with an air supply duct terminating near the bottom of the container so that air is discharged adjacent the bottom of the con tainer.

4. In a sand treating apparatus, the combination of a horizontally disposed bowl-shaped container for sand to be treated, a base supporting said container for rotation about its central vertical axis, means for rotating said container and the sand therein, a pair of circumferentially spaced kneading rolls having their central axes disposed in a horizontal plane and extending generally radiall of said container and having their peripheral faces spaced a desired distance above the bottom of said container whereby to exert pressure on the sand in said container, means supporting said rolls for rotation about their central axes whereupon movement of the sand under said rolls during rotation of said container causes rotation of said rolls and consequent kneading and squeezing of the sand, an agitator in said container disposed between said rollers and adapted to be buried in the sand in said container, and means supporting said agitator for rotation about a vertically disposed axis, said agitator being provided with a plurality of radially extending arms buried in the sand and closely adjacent the bottom of said container operative to rotate said agitator responsive to movement of the sand therepast during rotation of said container and thus agitate the sand and free the sand squeezed against the bottom of said container by said rolls, said agitator further being provided with an air supply duct leading to the arms of said agitator and discharging adjacent the bottom of the said container for aerating the sand.

5. In a sand treating apparatus, the combination of a horizontally disposed bowl-shaped container for sand to be treated, a base supporting said container for rotation about its central vertical axis, means for rotating said container and the sand therein, a pair of circumferentially spaced kneading rolls having their central axes disposed in a horizontal plane and extending generally radially of said container and having their peripheral faces spaced a desired distance above the bottom of said container whereby to exert pressure on the sand in said container, means supporting said rolls for rotation about their central axes whereupon movement of the sand under said rolls during rotation of said container causes rotation of said rolls and consequent kneading and squeezing of the sand, an agitator in said container disposed between said rollers and adapted to be buried in the sand in said container, and means supporting said agitator for rotation about a vertically disposed axis, said agitator being provided with a plurality of radially extending arms buried in the sand and closely adjacent the bottom of said container operative to rotate said agitator responsive to movement of the sand therepast during rotation of said container and thus agitate the sand and free the sand squeezed against the bottom of said container by said rolls, said agitator further being provided with an air supply duct leading to the outer ends of the arms of said agitator for aerating the sand during agitation thereof.

6. In a sand treating apparatus, the combination of a horizontally disposed bowl-shaped container for sand to be treated, a base supporting said container for rotation about its central vertical axis, means for rotating said container and the sand therein, a pair of circumferentially spaced kneading rolls having their central axes disposed in a horizontal plane and extending generally radially of said container and having their peripheral faces spaced a desired distance above the bottom of said container whereby to exert pressure on the sand in said container, means supporting said rolls for rotation about their central axes whereupon movement of the sand under said rolls during rotation of said container causes rotation of said rolls and consequent kneading and squeezing of the sand, an agitator in said container disposed between said rollers and adapted to be buried in the sand in said container, and means supporting said agitator for rotation about a vertically disposed axis, said agitator being provided with a plurality of radially extending arms buried in the sand and closely adjacent the bottom of said container operative to rotate said agitator responsive to movement of the sand therepast during rotation of said container and thus agitate the sand and free the sand squeezed against the bottom of said container by said rolls, said agitator further being provided with an air supply duct leading to the outer ends of the arms of said agitator for aerating the sand during agitation thereof, the under side of said arms being formed with radially extending channels leading to the outer ends of said arms.

'7. In a sand treating apparatus, the combination of a horizontally disposed bowl-shaped container for sand to be treated, a base supporting said container for rotation about its central vertical axis, means for rotating said container and the sand therein, a pair of circumferentially spaced kneading rolls having their central axes disposed in a horizontal plane and extending generally radially of said container and having their peripheral faces spaced a desired distance above the bottom of said container whereby to exert pressure on the sand in said container, means supporting said rolls for rotation about their central axes whereupon movement of the sand under said rolls during rotation of said container causes rotation of said rolls and consequent kneading and squeezing of the sand, an agitator in said container disposed between said rollers and adapted to be buried in the sand in said container, and means supporting said agitator for rotation about a vertically disposed axis, said agitator being provided with a plurality of radially extending arms buried in the sand and closely adjacent the bottom of said container operative to rotate said agitator responsiv'e to movement of the sand therepast during rotation of said container and thus agitate the sand and free the sand squeezed against the bottom of said container by said rolls, said agitator further being provided with an air supply duct leading to the outer ends of the arms of said agitator for aerating the sand during agitation thereof, the under side of said arms being formed with radially extending channels leading to the outer ends of said arms, said 8. The structure defined in claim 1 including power means for rotating said agitator. BENJAMIN A. SMITH.

8 REFERENCES CITED.

The following references are of 'recordin the file of this patent:

UNITED STATES PATENTS Number Name Date 660,278 Smith Oct. 23, 1900 1,374,445 Greenawalt Apr. 12, 1921 1,445,935 Daman Feb. 20, 1923 1,526,596 Greenawalt Feb. 17, 1925 1,718,004 Reed June 18, 1929 1,806,077 McMurray May 19, 1931 2,217,231 Morse Oct. 8. 1940 2,314,486 Dvorak Mar. 23, 1943 2,433,738 Christensen Dec. 20 1947