US1329094A - Plastic composition - Google Patents

Description

UNITED STATES PATENT OFFICE.

FRANQOIS RICHARD ANDFRAI Q'CIS M. BRADY, 0F CLEVELAND, OHIO.

PLASTIC COMPOSITION.

N 0 Drawing.

To all whom it may concern:

Be it known that we, FRANQOIS RICHARD and FRANCIS M. BRADY, citizens of the French Republic and United States, respectively, both residing at 7800 Finney ave., city of Cleveland, in the county of Cuyahoga and State of Ohio, have invented a new and useful Improvement in Plastic Composition, of which the following is a specification, the principle of the inventionbeing herein explained and the best mode in which We have contemplated applying that principle, so as to distinguish it from other inventions.

Our invention pertains to a plastic composition and more particularly to a vitric composition adapted to serve as a high tension and high voltage insulator, and besides fill a need in the manufacture of spark plugs.

The object has. been to produce a compound of the character stated which will be of great strength, which will be unimpaired by subjection to even sudden changes of temperature, and which may be easilydlnd economically manufactured in the forms desired.

The composition comprises the following ingredients (chemical substances) in substantially the proportions now given.

Silica fifty-five to sixty-five (5565) per cent. Alumina twenty (20) Ferrous oxid five to nine (59) Lime one to two 51-2) Magnesia .two to three 2-3) A1kalis s .tl1ree to five (3-5) The composition differs in appearance before and after vitrifaction'. It is whitish gray when first molded to shape While in a plastic state, but after becoming a fused compound takes on a reddish brown color. 1

The percentages are approximately as follows: Silica .sixtyper cent. Alumina a "twenty (20) per cent. Ferrous oxid .seven (7) per cent. Lime v0 (2) per cent. Magnesia two (2) per cent. Alkalis our (4) per cent.

'dred degrees (800-900) Fahrenheit Specification of Letters Patent. Patented J 311. 2'7, 1920. Application filed May,2, 1917.

Serial No. 165,833.

They are too friable and are over sensitive to quick temperature changes such as those which attend rain storms on excessively hot summer daysl.

Our invention is not merely dependent upon the essential substances nor upon the relative quantities used, but is vitally dependent upon the discovery of how best to approach the maximum degrees of heat.

The silica is the primary insulator, while the alumina and ferrous oxid lend the requisite toughness and strength respectively. The two oxids do not impair the predomi nant function of the silica as an insulator because they are themselves non-conductors.

The ingredients in the percentages previously listed are found in certain natural clays and are first pulverized, then put into plastic form by the addition of a suitable amount of water and worked or molded into the shape desired. Next the humidity is partly driven off with a dry warm air at a temperature of about one hundred degrees (100). If the humidity is not first driven off the mass will swell, warp and crack. The temperature must be left low untilall the steam has been driven ofi. Then a gradually increasing heat is applied to-start the burning of the carbon which is present in natural condition in such natural clay as has proven suitable. When eight to nine hunreached thecarbon will have been burned, and the metal oxids have fused or sintered. The carbon must be burned very slowly at temperature increases of, say, one hundred degrees (100) Fahreneit at intervals of about an hour. If the temperature is quickly raised the carbon gases inflate and disrupt the mass with the result that a light porous clinker ensues. After the carbon is Wholly burned the temperature may be raised with any rapidity.

At sixteen hundred degrees (1600) Fahrenheit a contraction ensues tending to effect a binding action. Thereafter the temperature is raised into the thousands sufficiently to fuse the ferrous oxid while still leaving the silica mainly in its natural state, that is, unfused.

The resultant vitrified product assumes a reddish brown color. The white specks in the sample are due to the dispensable pres-- ence of magnesia. The lime slags the silica and tends to help bind the Whole. The alkalis merely assist in some measure to efiect become partially hundred degrees (140W) which is also favorable to bind the mass.

Our composition has withstood a pressure of several tons to the square inch. It has been heated to from eight hundred to a thousand degrees (800-1000) Fahrenheit and then suddenly nnmersed in water without injurious results of any kind. It has satisfied the most extreme requirements of high tension insulation.

For practical use it would be preferable to glaze the exterior surface to minimize the adherence of soot in such quantity as might, if moistened, act as a conductor.

Another advantage which our composition has over fused aluminous compounds such as porcelain, is that it vitrifies at lower temperatures. The temperatures required in the making of porcelain are so high as to melt the steel cores on which it is frequently desirable and quite possible to vitrify our composition preparatory to shrinking the form thereon. In the case of our composition it is feasible to obtain a high tension insulator having a steel core as asupport therefor by subjecting such support to the vitrifying temperature together with our enveloping composition without injury to the steel. Moreover, an economy is realized in manufacturing our composition owing to the comparatively low temperatures at which the kiln may be operated.

Theemployment, together with the silica, offtwo. metal oxids which are fusible at different temperatures is an adoption which is thought to constitute a distinguishing feature.

We claim:

1. The process of making aninsulator which consists in mixing silica and carbon with lesser quantities of alumina and ferrous oxid with the addition of water and a binding substance, forming the mass, driving off the humidity by subjecting to a temperature around 100 Fahrenheit, gradually raising the temperature to 800 or 900 degrees Fahrenheit so as to burn out the carbon, thereafter rapidly increasing the heat applied until a contraction ensues, and finally raising the temperature sufliciently to inciplently fuse the ferrous oxid WllllG leaving the silica mainly unfused.

2. The above described process of producing an insulator by mixing with water a pulverized natural clay containing about sixty per cent. of silica, twenty per cent. of alumina, seven per cent. of ferrous oxid and the remaining per cent. lime, magnesia, carbon and alkalis, forming the mass to desired shape, subjecting the mass to low heat over a long period of time until the carbon is slowly burned out, and then greatly increasing the heat to partiall fuse the whole.

3. The process of ma ring a vitreous insulator, which consists in mixing a pulverized clay containing carbon, silica, alumina and ferrous oxid with enough water to make a plastic mass, shaping the same, heating slightly for a considerable period of time to slowly drive off steam, presently increasing the temperature and malntaining it at about SOO-900 until the carbon is burned out and finallygreatly increasing the heat until the mass is partiallyfused whereby to obtain a hard and tough product.

Signed by us, this 26th day of April, 1917.

FRANQOIS RICHARD. F. M. BRADY.

' Attested by- CURT B. MUELLER, PAUL MUnLLEn.