US1587621A - Process of conditioning sand for foundry use - Google Patents

Description

June 8 1926.

G. WALTHER PROCESS orconnmoume SAND'FOR FOUNDRY USE 1924 2 Sheets-Sheet 1 Filed April 4 //v VE/V 7-0/3 7 M,

June 8 1926.

G. WALTHER PROCESS OF CONDITIONING S-AND FOR FOUNDRY USE Filed April 4, 1924 2 Sheets-Sheet 2 WVE Tb/z WW1;

,4 770/?NEY Patented June 8, 1926.

UNITED STATES 1,587,621 PATENT OFFICE.

GEORGE WALTHER, OF MONTGOMERY COUNTY, NEAR DAYTON, 0310, ASBIGNOR TO THE DAYTON STEEL FOUNDRY COMPANY, OF DAYTON, OHIO, A CORPORATION OF OHIO.

PROCESS OF CONDITIONING SAND FOR FOUNDRY USE.

Application filed April 4, 1924. Serial No. 704,208.

This invention relates to a new and useful process of, and means for, conditioning sand for foundry use, and relates particularly to a progressive method of conditioning new and old sand for molding.

Used or hea sand, after being removed from the m0 ds, is first cleaned of all foreign substances such as wires, nails and metal particles which may get into it from the spilling of the molten metal, and also of all unusable or refuse sand.

Since at this point the used sand is still too hot from the castings to be used immediately, it is one of the principal objects of my invention to' cool the used sand to a normal temperature by suitable agitating and air blast means.

A concurrent step in my sand conditioning process is the drying of the new sand which, when received at the foundry, usually has a moisture content that is too high for use. By suitable agitating and heat projecting means, the new sand is dried at the same time the old sand is cooled.

The heap sand which has been cooled and the new sand that has been dried, are then properly proportioned and discharged automatically upon a conveyor by which they are carried to a bar mill where they are mixed and milled, or, in the nomenclature of the foundry, conditioned. This may be accomplished by any suitable means such as a revolving cylinder in which loose bars or balls increase the mixing action of the sand so that it may be discharged properly conditioned and ready for use in the molds. 1

Under my process the used sand need notv be cooled, nor the new sand dried, separately, but the cooling of the old sand and the dryingof the new sand may be accomplished by mixing them together in a suitable container such as a revolving cylinder, where the heat of the used sand evaporates the dampness of the new vsand; The used and the new sand while thus being mixed, are subjected to an air blast to aid in tempering the admixture by neutralizinlg the ex-. cess of heat in the old sand and the excess of dampness in the new.

The used sand and the new sand thus tempered, are then carried to the bar mill where a thorough mixture of the new and old sand is elfected by suitable agitating" devices such as round bars or balls,

preparatory for delivery to the. mac mes.

My process may be further simplified by passing the new sand direct from the sand storage, and the old sand direct from the cleaning means, to the bar mill where, the new and old sand are thoroughly mixed together in the presence of a. blast of air which neutralizes the excess of moisture in the former and the excess of heat in the latter.

From the bar mill, where its mixture is effected by suitable agitating devices, the new sand and the used sand are discharged as a properly conditioned mixture for delivery by suitable means to the conditioned sand pits and from them to the molding machines.

In its natural state the sand is ver open and without bmder. To give it consistency anartificial binder such as fire cla is applied to it, accompanied by a t orough mixing, so that the crystals of the sand may be coated with the binder to produce the proper adhesiveness during my progressive conditioning process.

Methods heretofore used are subject to the whims of the o erator, who can discharge the sand be ore it is thoroughly mixed. In my process the sand is handled automatically and cannot be discharged from the mill until it is thoroughly mixed. The time of mixing is predetermined by the incline of the mill, the quantity and weight of the agitating bars or balls and the speed at which the mill is revolved.

in the accompanying drawings, Figure l is a panoramic view of the means for carrying into eifect my process when separate devices are provided for cooling the old sand and drying the new sand. Figure 2 is a side elevationali view of the temperin and mixing means that may be employe for accomplishing my. process when the molding new sand and the old'sand are mixed to-.

gether, and subjected to a blast of air, in a revolving cylinder, prior to their introduction in a tempered condition to the bar mill. And- Figure 3 is. a side elevational view of the means. I employ for carrying into effect my process when the admixture of the new and old sand is carried on in the bar mill itself. I I

The hot used sand and the moist new sand may be properly conditioned for molding by my progressive process before outlined, by the use of se arate means for coohng the used sand an dryin'g the new sand, or by performing that operation in a single cylinder in the presence of an air blast, fore the tempered mixture enters the bar mill, or those operations may be accomplished in the bar mill itself, or any place alo the line.

. en the cooling and drying operations are performed separately, I preferably emloy the progressive means illustrated 1n i re 1. Included within these means is a suitablea 'tating device 1' from which the heap san from the shake-out is received, thoroughly agitated and deposited upon a suitable conveyorsuch as the belt 2 which asses over a magnetic pulley 3 in a screenmg device 4. From the latter the refuse is discharged by a chute 5 u on a ile while the screened sand passest roug the device and is deposited upon a'conveyer belt 7. By this belt the screened used sand is carried to the base of a suitable elevator 8 which raises it and discharges it into a suitable cooling cylinder 9, where it is agitated by a suitable agitating device 10 therein. Into this cylinder a blast of air is blown through a tube 11 to cool the used sand to a normal temperature during its agitation. s I

The screened used sand thus cooled is automatically de osited upon a conveyer such as the belt 12, y which it is carried to a bar mill 13 preferably on a floor 14 below. The latter is preferably the first floor, upon which the screenin device 4 and the agitating device 1. are a so supported. The cooling cylinder 9 is preferably mounted on the second floor 15. (See Figure 1.)

Also mounted on the second floor 15, opposite the cooling cylinder 9, is-a suitable drying cylinder 16 which receives the new sand through ,a chute 17. This new sand, which ordinarily has a high moisture content, is dried in this cylinder by any suitable means such as the oil flame 18 projected into the cylinder from a burner 19 secured in its inner head. Secured within the cylinder 16 v are axial agitating members 20 so that when the cylinder is revolved by suitable driving means, the new sand will be thoroughly agitated in it while .exposedto the flame 19.

. The c linder 16 automatically discharges the dri new sand upon a conveyer belt 12 in the sand w i is automatically de osited;u on the belt in proper proportions y the cylinder 9. The new and the" old sand are then conveyed together to the bar mill 13 where they are thoroughly mixed and milled by round bars or other suitable elements therein which increase the mixing action when the "mill isrotated. v

' 'lhe sand thus conditionedis deposited in the bottom part ofan elevator 22 by which means.

roger proportions to the cooled old it is raised for discharge into molding machine pits 23. By means of an elevator 24 the conditioned sand may then be raised from these pits and delivered to a chute 25 which discharges it into the molding machines 26.

As before brought out, the used sand may be cooled and the new sand dried by mixture together in a cylinder where the heat of the used sand will eva crate the dampness of the new sand. Thls combined step of my process may be carried out in any suitable device such as the cylinder 27 shown in Figure 2. The used sand which has been cleaned and screened by any suitable means such as those shown in Figure 1, is delivered, with the new sand from the new sand storage, into a chute 28 on the cylinder 27, the latter adapted to be revolved by any suitable To this chute the old sand is delivered by the elevator 8, and the new sand by a'conveyer belt 29.

Secured within the cylinder 27 are suitable agitating members 30 for thoroughly mixing the used and the new sand to permit the heat of the former to evaporate the dampness of the latter. Projecting into the chute end of the c linder 27 is a tube 31 in an air line from a an or blower (not shown) through which a blast of air is projected into the cylinder to aid in tempering the mixed sand by neutralizing the excess of heat in the used sand and the excess of dampness in the old sand.

The admixture of the used sand and the new sand thus tempered, is discharged from the rear end of the cylinder 27 upon a'conveyer belt 32 by which it is carried to a bar mill 33, where it is thoroughly mixed and milled in the same manner as in the bar mill 13. The conditioned sand is then discharged by the bar mill 33 into the lower portion of an elevator 34 by which it is delivered to the conditioned sand pits 23 shown in Fi and from thence to the molding machines 26 by the means therein outlined.

I As a more simplified form of my process, the used sand from the cleaning means, and the new sand from the new sand stora e, may be delivered directly to the bar mill or the purpose of conditioning with respect to coolm the used sand, dr ing the new sand and t oroughly mixing t em together. In Fi re 3 I have illustrated a bar mill 35 provi ed with an end chute 36 in which the used sand is depositedby the elevator 8 and to which the new sand is conveyed by the belt 29. Within this bar mill which 1s revolved by suitable means, are round bars 37 that preferably run the length of the bar mill to increasethemixing action, although other suitable agitating devices could be emplo ed if desired.

- y means of an air line 38 from a fan or blower not shown, an air blast may be pro- III jected into the bar mill 35 during the mixing operation, to temper the admixture by neutralizin the excess of heat in the old sand and t e excess of moisture in the new sand. If the new sand should come to the bar mill dry, as in warm weather, and the used sand should be delivered to it after standing a sufiicient time to cool, then the air blast may be reduced or shut-ofi entirely. The new sand and the used sand when tempered and mixed in the bar mill '35, may be delivered to the molding machines by the means illustrated and described.

In order to impart consistency to the sand so that it may hold its shape, a bindersuch as fire clay should be added, and thoroughly.

mixed with it, to coat the crystals of the sand to produce the pro er adhesiveness.

Under my process t e sand is handled automatically and can not be discharged from the bar mill until it is thoroughly mixed. Furthermore, the process is progressive, economical and efiicient, and eliminates many separate and distinct steps and operations which areby my method combined in a progressive and unified whole.

It is also possible under my process to just condition the oldsand in the bar mill, and use it as facing and molding sand and occasionally mix it with the new sand.

Having described my invention, I claim: 1. The herein described process-of mixmg new sand and old sand for molding, which consists in bringing the new sand and the old sand together, and then introducing air into the mixture to neutralize the excess of dampness in the new sand and the excess of heat in the old sand.

' 2. The herein described process of conditioning new sand and old sand for molding, which consists in bringing the new sand and the old sand together, then introducing air to themixture to neutralize the excess of dampness in the new sand and the excess of heat in the old sand, and then mixing the tempered new sand and old sand.

3. The herein described process of 0011- ditioning new sand and old sand for molding, which consists in first bringing the.

new sand and the old sand together, then introducing the same to a mixing. chamber,

5. The herein described process of conditioning sand for molding, which consists in mixing new sand and old sand together while subjected to a blast of air, and thereafter mixing and milling the tempered sand.

6. The herein described process of conditioning sand for molding, which consists in revolving new sand and old sand together while subjected to a blast of air, and thereafter revolving the tempered sand.

' 7. The herein described process of conditioning' sand for molding, which consistsin first cleaning old sand, then mixing it' with new sand while subjected to a blast of air, and thereafter mixing and milling the tempered sand.

In witness whereof I have hereunto set my hand this 2nd day of April, 1924.

GEORGE WALTHER,

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