US678488A - Method of tempering molding-sand. - Google Patents

Description

UNITED STATES PATENT OFFICE.

GEORGE K. I-IOOPER, OF DEDI IAM, MASSACHUSETTS.

METHOD OF TEMPERING MOLDING-SAND.

$PEGIFIGATION fOrming part of Letters Patent N0. 678,488, dated July 16, 1901. Application filed April 12, 1901. SeriaI N0. 56,591. (No specimens.)

To all whom it may concern.-

Be it known that I, GEORGE K. HOOPER, a citizen of the United States, and a resident of Dedham, in the countyof Norfolk and State of Massachusetts,have invented a'new and Improved Methodof Tempering Molding-Sand, of which the following is a specification.

My invention consists of a new method of tempering molding-sand 'for foundry purposes, whereby a determined initial amount of moisture is imparted to the mass of sand uni formly and to a desired degree throughout,-

thus enabling the workman to dispense with the tentative and in many cases unsatisfactory mixing processes which have heretofore been in vogue. v

Tempering molding-sand consists in bringing the mass of sand to adegree of dampness which adapts it to the work of making molds for castings. The precise degree to. which molding-sand is moistened varies with the experience and estimation of different foundry masters, and within fairly narrow limits the moisture of tempering sand difiers in different foundries; but in all cases heretofore known to me the method with which molding-sand has been impregnated with moisture is as follows: The molding-sand when turned out of the molds to be broken up and screened is too dry for'use in molding and has to be moistened; As thesand passes through the various screening and mixing operations it absorbs more or less moisture, according to the condition of the atmosphere, and therefore when the work of moistening is begun no one knows actually how much water to add to a given mass of sand. The moistening has been done in a very crude way, water being added to the mass of sand, which is then mixed either by hand or machinery until the moisture is distributed as evenly and thoroughly as possible by such methods, when the workman tests the temper of the sand by feeling of it. If in his opinion it is too dry, more Water is added and the mixing repeated. If it is too wet, a rudely-measured quantity of dry sand is thrown into the moist mass and the mixing repeated, and by such methods as these the sand is gradually brought to a condition which satisfies the operator. This requires a high degree of skill based upon long experience, and even then is not uniformly satisfactory, as the imperfections in castings testify.

My method of preparing molding-sand for moist. The degree to which this moisture 6 may be brought may be satisfactorily regulated by regulating the charge of the moisture of the atmosphere in the room where the tempering is done. The man in charge by observing a hygrometer placed in the room can readily produce the desired degree of charge of moisture in the atmosphere by means of admitting vapor from steam-pipes or by atomizer-sprays which fill the air with finely-subdivided particles of water, and by noting the correspondence between a given indication of the hygrometer and the desired temper of the sand the operator can at all times produce and maintain an atmospheric condition perfectly suited to the accomplish- 8o ment of his purpose. By this means the sand comes to the final tempering process in an exactly=determined condition of moisture,and the man in charge of the work knows beforehand exactly how much water to add to a given weight or bulk of sand. A short experience with the moisture-charged air enables the sand-temperer to measure out the requisite quantity of water, add it to the initially-moistened the mixing, confident that no further testing or manipulation will be necessary. All the tentative hand manipulation and rule-of thumb addition of water is done away with.

The sand which goes to the molding-room is 5 practically uniform in quality and no poor castings need be expected to result from improperly-tempered sand. This method will be found especially valuable in foundries wherein a continuous=conveyer system of 100 The dry sand absorbs moisture from 60 sand, and then proceed with molding and casting is employed which calls completing the moistening by adding to the for rapid and uniform delivery of tempered sand a quantity of water in bulk, the said sand to the molding department. quantity being proportionately determined What I claim, and desire to secure by Let with reference to the atmospheric moisture of 15 5 ters Patent, is-'- preparation.

The method of tempering molding-sand, Signed bymeatBoston,Massachusetts,this which consists of maintaining a moisture- 4th day of April, 1901.

charged atmosphere in aninclosed space, ma- GEORGE K. HOOPER. nipulating the sand in the said atmosphere, Witnesses: 10 thereby imparting to the sand a uniform ini- E. TOLSTOLL,

tial degree of moisture, and subsequently FRANK S. HARTNETT.