|Publication number||US2512567 A|
|Publication date||Jun 20, 1950|
|Filing date||May 22, 1948|
|Priority date||May 22, 1948|
|Publication number||US 2512567 A, US 2512567A, US-A-2512567, US2512567 A, US2512567A|
|Inventors||Milligan Lowell H|
|Original Assignee||Norton Co|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (3), Referenced by (5), Classifications (10)|
|External Links: USPTO, USPTO Assignment, Espacenet|
| H. MILLIGAN June 20, 1950 BATT Filed May 22, 1948 Inventor LOWELL H. MILL/GEN Patented June 20, 1950 BATT Lowell H. Milligan, Worcester, Mass, assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application May 22, 1948, Serial No. 28,690
The invention relates to batts for use in kilns, furnaces and the like.
One object of the invention is to provide a refractory batt capable of withstanding intense thermal shock. Another object of the invention is to provide a refractory batt capable of Withstanding irregular heating or cooling of high differential, that-iswhere one part of the batt is at a different temperature from that of another part. Another object of the invention is to provide a batt which is mechanically strong and resistant to heat shock and thermal differential. Another object of the invention is to provide a batt of the character indicated of long life. Another object of theinvention is to provide a long-life batt of largesize. Another'object is to provide a longlife batt for building stands of ware that are to bev heated and cooled from the directions of the edges of thebatts. Another object of the invention' is to provide long-life batts for use in a kiln provided with sources of heat above and/or below the batt; Another object of the invention is to provide a round batt with one or more of the above characteristics. Other objects will be in part obvious or in par pointedout hereinafter.- I w i The invention accordingl consists in the features of construction, combinations of elements and arrangements of parts all as will be illustratively described herein and the scope of the a plication of "which will be indicated in the following claims; -:';In the accompanying drawings illustrating one of many possible embodiments of the mechanical features of this invention,
I Figurel is a plan view of the batt on a small scale,
Figure 2 is a fragmentary plan view of the batt on a larger scale,
Figure 3 is an elevation of the batt looking in the direction of the arrows v33 of Figure 2.
As conducive to a clearer understanding of the present invention, a batt is a plate or other shape to hold ceramic or other ware during a heating operation. Thus, for example, green ceramic articles, such as unfired molded spark plugs, dishes or grinding wheels ar placed on batts which are then put into or passed through a kiln, and the spark plugs, grinding wheels or dishes are fired,
that is to say, vitrified. The batt is therefore necessarily a refractory article.
Many ceramic manufacturers have estimated the cost of batts on the total cost of their product and in practically all cases it has been found that the cost of batts is a large percentage of the cost 4 Claims. (01. -25153) of manufacturing the ceramic product which is sold. This is so because there is not merely a first cost of the batts but the cost of continually replacing batts. A batt is cold when it is placed in a kiln but becomes heated to the firing temperature or temperatures, usuall high, in the kiln, then it'is allowed to cool or may be rapidly cooled byspecial means such as blowing air on it, and later on, after becoming cold, it is used again to support more green ware and is again heated, allowed to cool, and so on. Batts do not indefinitely survive this alternate heating to high temperaturesand cooling even if the temperature gradients are gentle; Eventually the batts break or crack and While a cracked batt may be used, it eventually becomes a broken batt and thereafter useful if at all only for smaller pieces of ware, and eventually, after further cracking or breaking, not at all. The foregoing being true even when the slope of the temperature-time curve is very slightyit is all the more true and the percentage of the cost of batts to the total cost of manufacture of the product is much greater when the slop of thetemperature-time curve is steep. Batts are customarily made of materials that are maturedto a strong condition at temperatures higher than those experienced by the batt in use. This gives aproduct having maximum stability in use against change in dimensions, etc. It is advantageous to employ materials of as low expansivity' as feasible so as to reduce the amount of dimensional change and resulting stress as a function of temperature change. Batts and other kiln furniture hav long been made of refractory fire clays. These give products of satisfactory expansivity characteristics but of relatively low strength and low heat conductivity. Silicon carbide as the main ingredient of batt mixtures gives improved products because in addition to'lowexpansivity they'have high strength andhigh heat conductivity. Likewise, batts composed of mullite which mullite may have been essentially originally of the electric furnace fused variety, or may have been developed by the maturing operation to which the batt was subjected in manufacture, hav advantages over fire clay batts. Furthermore; refractory'batts for very high temperature use "m-ay now be made as sintered or recrystallized products, often substantially bondless, many of which may be classed as pure oxide refractories. This invention, although described particularly for silicon carbide products, is also advantageous when embodied in batts composed of other refractory materials.
As an example of a bonded silicon carbide composition for batts according to the present invention, I may make a mixture according to the following formula:
The silicon carbide is the ordinary black-grade and is put into a mixing machine of conventional type and the dextrine is added. After mixingfor a minute or two the water is added and mixing is continued for-a minuteortwdmore; Then: the balliclay: and rye-.fiour are screenedinto themix together: and the; mixing is; continued 1' for five minutesmore. This-:pr.ocedure. producesaxdamp granular mixture that is suitable for tamping or pressing.
Figures 1. 2iand3'show. anzrexample of: a batt according: to this: invention; This is round and flat, thatis to' say it'xisza circular. disc-and may or may not have a central hole it. Preferably it has an essentially flat side Hand anessentiallyfiat sidel'z bound by acylindrica'l edge: l3.- Although theside ll isshownzas thetop sideand therside l 2 as the bottom side, the batt is reversible in the example given,
The batt has apluralitynof?indentations arranged in clusters l5, each cluster'of indentations being elongated and 'extending-in-radiai directions from the periphery or, edge :l-Sltowardfthe: center of the batt but preferably stoppingishortt thereof and. each indentation extendingzfrom asurface H or I2, therebeing-preferably:ineachucluster at least oneindentationfrom each surface. This construction is: accordion-like with the indentations running radially so that; differences. Ofx expansicn-betweenconcentric circlesof tthetbatt are accommodated-and will nottcrack the..batt;.
The invention can havema'ny practical embodiments but forillustration :there'is herein disclosed the best embodimentnow: lmowntor me which is simple, well balanced, and easy to: manufacture. Thus, and referring now especially to Figure 3, each cluster!Ecomprisesthreeradially extending tapered bores l6, l1 and IBceXtending fromthe periphery orredge 13 about half way. to the center ofthe batt, the;bores:: lS-and [8 being connected by straight slots: l9: and with: the surface I2 andthe bore I! being: connected. by a straight: slot 2|: with the surface: H. As-illus trated, thebores; i 6, 1 land; I 8; are. all of the-same dimensions" and. likewise the: slots l9; 20 and 21 are'of' the same dimensions;-:, This-radialiboring and. slotting off thev batti leaves: connecting wall portions. 22; and 23 asiwell as; connecting wall portions-24, 25;and 26;which, being-thinner than the: total thickness of theabatt can flex somewhat more-than a solidbattcould flex without breakage and; furthermore if, each one; of; the portions: 2.3 to- 25 flexes: a little bit, the total deformation without breakage can be much greater than could the total deformation in the case of a solid batt.
In a circular batt the greatest strains and stresses are likely to be set up near the periphery. Furthermore, such strains and stresses are exerted along concentric circles. By the construction described thesestrains and stresses are adequately absorbedup to extreme conditions of differential heating or thermal shock.
It will thus be seen that there has been provided by this invention a batt in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may bepmad-e, ofthe above invention and as many changes might be made in the embodiments above. set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
1. A batt for kilns, furnaces andthe like genorally inthe form of a" circular disc; having a plurality of clusters of indentations each cluster being elongated and extend'ingin radial directions from the periphery'towardsthe center oftheibatt and each cluster comprising'bores connected by straight slots with a: surface ofthe batt the slots being tapered inwardly towards. the center of the batt;
2; A batt for kilns, furnaces'and thelike generally in the form of a circular" disc; having a plurality of clusters of indentations'eachcluster being elongated and extendin in radial directions from the periphery towards the-center ofthe batt and each cluster comprisingbores connected by straight slots with a surface of the batt the slots being tapered inwardly towards the center of the batt and each cluster' having at least one slot'extending from each surfaceofthebatt.
3. A batt for kilns, furnaces and: the likegenerally in the form of a circular disc, having aplu ralityo-f clusters of indentations each cluster-being elongated and extending in-radial' directions fromthe periphery towards the center of the batt, there being an indentation in eachsideof-the batt in each cluster, each indentationextendlng from-a surface of-the batt at least halfway to the other surface of the bait along the major portionof its length but the indentations anotextending clearthrough' the batt along any considerable radial distance, and there being between the indentations wall portions of the batt which are'thinner than'the total thickness of the bait;
4. A batt according to claim3' in which-the indentations are tapered inwardly towards the center of the batt.
LOWELL H. MLHGAN;
REFERENCES CITED The following references are of record in th file of this patent:
UNITED STATES PATENTS lf urrlbe Name- Date 1,215,067 Simonds Feb. 6; 191'? 1,485,110 Beth Feb. '26; 1924 1,393,123 Beth Jan; 8, 1938
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US1215067 *||Mar 25, 1916||Feb 6, 1917||Herbert R Simonds||Apparatus and process for baking emery-wheels and the like.|
|US1485110 *||Dec 15, 1920||Feb 26, 1924||Norton Co||Tunnel kiln|
|US1893123 *||Feb 13, 1931||Jan 3, 1933||Norton Co||Tunnel kiln car|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4536153 *||Feb 23, 1983||Aug 20, 1985||Anthony Frank H||Refractory shelf for home hobbyist kiln and method of making kiln|
|US4725474 *||Jul 23, 1984||Feb 16, 1988||Norton Company||Batt of refractory material|
|US4778383 *||Aug 25, 1987||Oct 18, 1988||Hutschenreuther Ag||Apparatus for firing ceramic shaped products|
|DE10307341A1 *||Feb 21, 2003||Sep 2, 2004||Bayerische Motoren Werke Ag||Ceramic support plate for crown wheel, includes cylindrical support disks which are supported by frame such that each support disk consists of 68 percent silicon dioxide, 18 percent silicon carbide, and 14 percent aluminum oxide|
|DE10307341B4 *||Feb 21, 2003||Feb 2, 2006||Bayerische Motoren Werke Ag||Tragplatte zur Aufnahme eines Tellerrades|
|International Classification||F27D3/12, B28B11/24, F27D5/00, B28B11/00|
|Cooperative Classification||F27D5/00, B28B11/24, F27D2003/124|
|European Classification||B28B11/24, F27D5/00|