US2201989A

US2201989A - Ceramic support

Info

Publication number: US2201989A
Application number: US178285A
Authority: US
Inventors: Arthur L Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-12-06
Filing date: 1937-12-06
Publication date: 1940-05-28
Anticipated expiration: 1957-05-28

Description

May 28, 1940. A. L. DAVIS 2,201,989

CERAMIC SUPPORT Filed Dec. 6, 1937 2 Sheets-Sheet 1 FIG l FIG. 3

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FIG. IO FIG. I2

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|NvENToR May 28, A DAVls CERAMIC SUPPORT Filed Dec. 6, 1937 2 Sheets-Sheet 2 FIG. I3

FIG. I4

INVENTOR Patented May 28, 1940 (Granted under the act of March 1883, as amended April 30, 1928; 370 O. G. 757) OFFICE The invention hereinv described may be manufactured and used by or for the Government for governmental purposes Without the payment to me of any royalty thereon.

lain type ceramic ware. In the hitherto known methods of firing, the processes commonly used do not provide any Way for bracing the centers of the ware, which have a tendency to drop if the This invention relates to the art of ring Ware is thin; the processes used do not make it 5 ceramic ware in kilns and particularly to an impossible to stack the ware to a suiiicient height, proved ceramic support element. say not more than 12 high; the processes used l One of the objects of this invention is to prodo not appear to overcome strains which are invide a support for formed ceramic ilatware troduced into the ware during the forming opwhich provides for the firing of ceramic ware eration; the processes used have a tendency to l0 more uniformly by forced circulation of the atshow up the internal strains after a biscuit is mosphere in the firing zone adjacent to the ware. fired in spite of the bracing; the materials used Another object of this invention is to provide for. bracing carry an excessive amount of dust;

a support for formed ceramic flatware articles the materials used for bracing considerably af- 15 which will hold the articles in substantially perfect the ti'anslucency of the ware and have a 15 feet alignment during firing notwithstanding the tendency to pack and fuse into the ware; and presence of internal strains resulting from the the materials .used for bracing have to be reprocess of forming these articles. Another object ground or otherwise treated before re-use. of this invention is to provide support elements I have discovered a ceramic ware support elelo for use in firing a plurality of ceramic atware ment for use in a vertically aligned assemblybf articles in order that assemblies containing a a plurality of superposed fired ceramic ware suplarge number of these articles may be red with port elements and a plurality of unred ceramic the production of a maximum number of perfect articles in which each article is between two articles as a result of the firing. Other objects support elements. 'Ilie respective ceramic ware of this invention include the provision for rsupport elements are comprised of a ring of uni- 25 ing formed ceramic fiatwire articles in an ecoform thickness with the upper side in a true nomical manner on ceramic support elements horizontal plane and with a plurality of oblique which may be economically reused by firing sucapertures through the ring or on the lower side cessive assemblies of the articles. of the ring so that an aperture is formed when :zo Ceramic flatware is easily formed by jiggering the ring rests upon a support element immeor casting from semi-vitreous or hotel china type diately below it. These oblique apertures pass bodies, but such articles present a difficult probthrough the ring at substantiallythe same angle lem in delivering the ware straight from the lirin substantially a horizontal plane. lThe presing kiln. Deformation in lred ceramic articles ence of such oblique apertures accelerate the pasis caused for the most part by internal strains sage of the atmosphere of the kiln both above and 35 arising from one or more of the following l below the article being `red and thereby cause sources: characteristics of the plastic body from a more rapid heat transfer which consequently which the articles are formed, method of formresults in maintaining a more uniform temperaing the ceramic articles, and skill or lack of skill tui-e throughout the ring operation, Such im- 4o exhibited during the forming operation. These proved Circulation of the gaseous atmosphere 40 internal strains are subsequently evidenced, first, generally results in reduced firing time- Inciduring the drying 0f the f ofmed Ceramic article dentally the use of such support elements mateand second, during the ring of the dried formed riauy reduced the time required for drying the ceramic articles. Kiln placing methods, such as ceramic Ware before ming used in the manufacture of true ppmeltam In the accompanying drawings, which form a 45 Beneek' and bone .chma www m a satlsfac Ory part of the specication, and wherein reference product but the kiln capacities are severely reb 1 f t rk t h r the C u stricted. This latter objectionable feature might Sym 0S re er o 1 8 par s w e ever y o c r be overcome provided a kiln ill equal to or better Flg' 1 ls a plan Vlew 0f the bverse 51de of one than that obtained using semi-vitreous or hotel Shape of? forme@ Ceramlf: artlcle; 50

china type ware could be employed wherein sand, Flg- 2 1S a Vertlcal Sectlon of F1g- L cicined kaoiin and mixture of caicined kaoiin Fig. 3 is a plan view 0f the Obverse 51de 0f anand alumina are filled in between the plates. other shape of a formed ceramic article.

This has not, however, been hitherto attained Fig. 4 is a vertical sectional view of Fig. 3. particularly in connection with the use of porce- Fig. 5 is a plan view of the obverse side of a 55 fired ceramic support for use in connection with ring the article shown in Figs. 1 and 2.

Fig. 6 is a vertical sectional view` of Fig. 5.

Fig. '7 is a. plan view of theebverse side of a fired ceramic support for use in connection with firing the article shown in Figs. 3 and 4.

Fig. 8 is a vertical sectional view of Fig. 7.

Fig. 9 is a plan view of a fired refractory setter for ring the ceramic article shown in Figs. 1 and 2.

Fig. 10 is a vertical sectional view of Fig. 9.

Fig. l1 is a plan view of a fired refractory setter for firing the ceramic article shown in Figs. 3 and 4.

Fig. 12 is a vertical sectional view of Fig. 11.

Fig. 13 is a vertical sectional view of an assembly of the red ceramic supports as shown in Fig. 6 and Fig. 8, a plurality of formed ceramic articles shown in Figs. 2 and 4, (with only two such articles shown for purposes of illustration), and a ilred refractory setter as shown in Fig. 10 and Fig. 12.

Fig. 14 is a vertical sectional view of the assembly shown in Fig. 13 after ring the ceramic articles to the desired maturity.

In'Fig. 1, Fig. 2, Fig. 3, and Fig. 4, formed ceramic articles, represented by ceramic article 2, are shown prepared for firing.

In Fig. 5, Fig. 6, Fig. 7, and Fig. 8, fired ceramic supports, represented by ceramic support 4, are shown ready for assembly prior to firing ceramic articles 2. The fired ceramic support 4, is provided with an outer ring 6, embodying a plurality of pilot stud recesses, represented by pilot stud recess 8, and a plurality of pilot studs, represented by pilot stud I0, allowing inter-engagement of the stud and recesses when the supports are stacked. Adjacent to and integral with the outer ring 6, an inwardly projecting flange l2, is provided, whose upper side I4, and lower side I6, are both inwardly declined corresponding to the reverse and obverse sides respectively of the finished articles. Passing through the outer ring 6, and flange l2, obliquely to the perifery of the ring 6, are a plurality of apertures, represented by aperture I8. Attached'to the flange I2, are a plurality of arms, represented by arm 2D, inwardly declined and converging to a center portion 22, which supports the center of the unfired ceramic article 2.

In Fig. 9, Fig. l0, Fig. ll, and Fig. l2, fired refractory setters, represented by fired refractory setter 24, are shown ready for assembly prior to firing ceramic articles 2.

In Fig. 13, a plurality of unilred ceramic articles 2, as shown in Fig. 2 and Fig. 4, and a plurality of red ceramic supports 4, as shown in Fig. 6 and Fig. 8, are assembled on a fired refractory setter 24, as shown in Fig. 10 and Fig. 12. The ceramic article 2, rests on the upper side I4, of the flange l2, and the center portion 22, of the fired ceramic support 4. The lower side I6, of the flange l2, of the fired ceramic support resting on the aforementioned fired ceramic support 4, is complementary to a portion of the obverse side of the unfired ceramic article 2, with sufficient distance between the lower side of the fired ceramic support and thr obverse of the unfired ceramic article 2, to be within the tolerance limit of the ceramic article.

In Fig. 14, the lower side IE, of the flange l2, is shown within substantially the tolerance limit of the fired ceramic article 26, whereby the rim of the ceramic article 26, has been maintained accurately positioned within the tolerance limit throughout the entire firing operation.

It is evident that there are numerous factors which will influence conditions for the most satisfactory operation of my invention, the actual limits/'of which cannot be established except by "fitailed study of each set of raw materials and finished products involved.

The ceramic support elements are preferably made from a body which will not impart any undesirable discoloration during firing, but, of course this will depend upon the material of the ware being fired, the temperature to which it is fired and the nature of the atmosphere in which it is ilred.

The ceramic support elements may be formed by conventional methods such as jiggering or casting. In order, however, that the elements may be uniform to obtain perfect horizontal and vertical alignment during assembly, it is generally necessary to machine a part or all of the respective faces of the element before firing or after firing in order that the fired support elements prepared for use may have the necessary uniformity.

The support elements used in an assembly for firing a plurality of ceramic articles, should all have substantially the same coefficient of expansion. Furthermore they should be of such a composition that they do not exhibit any appreciable plasticity at the temperature of firing of the ware in order that there be practically no deformation of the supports and consequently provide accurate support for the ware.

Each support element is provided with a ring of uniform thickness in at least three zones or an equivalent for the purpose of accurate vertical alignment. Each ring is provided in the zone intermediate to the zones of uniform thickness with an aperture or apertures suitable for admitting the heated gaseous atmosphere contained within the firing zone in order that the ware being fired may be heated more uniformly. Generally the ware so heated can be brought to the desired maturity in a shorter period of time than is possible by conventional methods. By more uniformly heating the ceramic article during the various stages of firing it is possible to obtain less deformation than would otherwise result.

The ceramic flatware articles may be formed by conventional methods, such as jiggering or casting. This invention relates specifically to the support elements used in the production of ceramic flatware articles with an exterior edge or rim of any desired shape. This invention is particularly adapted for use in the production of ceramic flatware articles having intricate design on the obverse and/or rim.

The zones of deformation of a formed ceramic flatware article during firing are first, the center of the article at which gravity probably exerts the most predominate influence, second, the zone through the center line of the foot and third, and by far the most important, the exterior rim of the article where deformation is caused by gravity on the one hand and marked unevenness by the effect of internal strains in the body of the formed ware on the other hand.

Deformation of ceramic flatware articles during firing can be substantially reduced by firing stacks of flatware articles with their respective zones of most serious deformation, supported by an element which has a central portion of such size and so positioned as to support at least the perifery of the central area of the reverse of the ceramic article and a flange, connected by arms to the center portion, inwardly declined with the upper side of the ange complementary to a portion of the reverse of the ceramic article at the rim of the latter. In addition, each such flange has a lower side which is complementary to a portion of the obverse of another ceramic article in the assembly, immediately below the first mentioned ceramic article, at the rim of the former with a space between the lower side of the flange and the obverse of the ceramic article within the tolerance limit of the ceramic article. This maintains the ceramic article being fired in positive alignment throughout the entire firing operation.

It is generally desirable to use a true shape refractory setter with its obverse side so shaped as to be complementary to the reverse of one of the ceramic support eleilients.

In assemblying the ce amic support elements and the unred ceramic ware alternately, the support elements may be vertically aligned in an alignment rack or the support elements may be originally provided with the necessary pilot studs and pilot stud recesses or their equivalent.

It may be necessary to separate the unred ceramic articles and the support elements from each other, when assembled for firing the former, by the use of a finely divided refractory which is substantially neutral to the body from which these elements are made at the temperature of subsequent firing. A finely divided alumina, such as finer than mesh, has been found suitable for this purpose,

As assembly of ceramic support elements and unred ceramic articles are fired under conditions of temperature, time and atmosphere to obtain the desired maturity. During the firing there is appreciable shrinkage of all the originally unfired ceramic articles in the assembly with this shrinkage varying considerably with the plastic material from which the articles are formed. They may, for example, vary from 8 to 18%.

After firing the assembly is dismantled and the finely divided refractory adhering to the fired ceramic articles is removed from the articles and the support elements inspected and made available for use in firing subsequent assemblies.

Certain terms used throughout the description and claims are understood to have the following meaning: obverse refers to the top of the article or element as assembled for firing regardless of how the article or element is actually formed and likewise reverse refers to the bottom of the article or element as assembled for firing regardless of how the article or element is actually formed.

It will be seen, therefore, that this invention actually may be carried out by the use of various modifications and changes without departing. from its spirit and scope, with only such limitations placed thereon as are imposed by the prior art.

I claim:

1. In a vertically aligned assembly of a plurality oi' superposed fired ceramic ware support elements and a plurality of unred ceramic articles in which each article is between two support elements, a ceramic ware support element which comprises a member having a continuous outer portion of uniform thickness and substantially uniform width defining a space of greater extent than that occupied by the ceramicarticle, and an inwardly declined continuous portion integral therewith for supporting the reverse of a superposed unred ceramic article adjacent to the rim of said article; a plurality of oblique apertures extending through both of said portions for effecting a circ-ulation of a fluid heating medium between'adjacent ceramic articles; a plurality of spaced nwardly declined arms integral with said porti s; and a continuous center portion integral with the ends of said arms opposite said first named portions for supporting the central area of the reverse of a ceramic article.

2. In a vertically aligned assembly of a plurality of superposed red ceramic ware support elements and a plurality of unred ceramic articles in which each article is between two support elements, a ceramic ware support element which comprises a member having a continuous outer portion of uniform thickness and substantially uniform width defining a space of greater extent; than that occupied by the ceramic article and an inwardly declined continuous portion integral therewith for supporting the reverse of a superposed unred ceramic article adjacent to the rim of said article and to maintain the obverse of a subjacent unred ceramic article adjacent to the rim of said article in positive alignment; a plurality of oblique apertures extending through both of said portions for effecting a circulation of a fluid heating medium between adjacent ceramic articles; a plurality of spaced inwardly declined arms integral with said portions; and a continuous center portion integral with the ends of said. arms opposite said first named portions for supporting the central area of the reverse of a ceramic article.

ARTHUR L. DAVIS.