US508653A

US508653A - Insulating composition

Info

Publication number: US508653A
Authority: US
Publication date: 1893-11-14
Anticipated expiration: 1910-11-14

Description

(No Model.)

THOMSON. INSULATING (JGMPOSITION;

Patented Nov. '14

L E F WITNESSES- ms NATIONAL umcqmmme ccMPANv.

WASHINGYON. n4 0.

ELIHU THOMSON, OF SWAMPSCOTT,

:PATENT OFFICE.

MASSACHUSETTS, ASSIGNOR TO THE THOMSON-HOUSTON ELECTRIC COMPANY, OF CONNECTICUT.

INSULATING COMPOSITION.

SPECIFICATION forming part of Letters Patent No. 508,653, dated November 14, 1893.

Application find November 2, 1891.

To all whom it may concern.-

Be it known that I, ELIHU THOMSON, a citizen of the United States, residing at-Swampscott, in the county of Essex and State of Massachusetts,have invented certain new and usefullmprovements in Insulating Compositions, of which the following is a specification.

My present invention relates to the production of slabs of insulating material suchas are suitable for use in the construction of dynamo electric machines in place of mica where strength, together with some flexibility is required, and wherethe material must resist the formation of carbonized lines or carbonized paths through the same transverselyto the sheet or slab.

In the accompanying drawings Figure 1 inch in thickness, more or less,) and coat or impregnate the same with a deposit or a thin layer of mineral substance such as a mixture of fine kaolin or silicious compound or equivalent thereto and soluble silicate of soda. This may be done by applying a silicious solution to the paper. I pile these sheets as shown in Fig. 1, into a mass A, which gives a slab of the desired thickness. The silicious material will thus be incorporated more or less with the paper and may penetrate throughout the same or may be mostly on the surface,in the form of a coating or layer, which should, however, be as thin as practicable. The mass is then dried out so as to remove all moisture from it, and then forms thin slabs of insulating material which are adaptable to many purposes, the strength being conferred by the paper while the deposit or layers of silicious matter form insulating layers which prevent the formation of a carbonized line of particles across the same. Hence the compound may be used in commutator insulation between the segments or the like. The alternate ar- Serial No 410,603. (No specimens.)

rangement of the paper layers a and the sili cious coatings b is indicated in Fig.2. While the material simply. dried in this manner is adapted for many purposes, I prefer to perfect the substance-by baking it at a moderate red heat whereby the paper is more or less carbonized and the silicious matter more or less vitrified or fritted together into a thin, flexible slab with carbonized paper more or less incorporated therewith. In other cases I heat the slab in contact with air for a sufficient time to burn out the carbonaceous matter left by the paper. In this latter case however, the strength will not be as great. By baking as described, there is obtained a series ofthin slabs of insulating material resembling baked porcelain, clay, or half formed glass which may be retained in the form of a slab or split up into layers, as desired.

I prefer to make the silicious deposit mainly as a coating or external layer, so as to give distinct silicious layers in the completed article. By burning out the paper completely it is even possible to separate the layers after baking so as to obtain thin flat sheets of what would resemble porcelain. In this case the invention is practiced as follows, the object being to produce a series of thin plates of porcelain biscuit or unglazed porcelain made at a comparatively low temperature. I take the paper sheets and place between them thin slabs of the clay or silicate mixture and pile them one above the other,-paper, clay mixture, paper, clay mixture, &c., to any desired thickness. I then thoroughly dry the mass as uniformly as possible so as to avoid warping. It is then baked at a moderately high temperature such as a bright red heat and if desired the heat continued until the paper being carbonized is burned out by the presence of oxygen. 1 then haveabundle of thin slabs which may be either used as such or by separating them one from the other, as desired, by splitting them apart. By shaping the coated paper into the proper form, the finished material may be made to take any form de sired, for example that indicated in Figs. 3 and 4, and to consist of layer upon layer of the vitreous substance separated by what remains of the paper as carbonized material or as ash according to the degree of baking, although my process, as stated before, does not necessarily involve the baking process if the ma terial is not to be waterproof.

Instead of silicious compounds I may use any other materials, of the requisite insulating and non-carbonaceous nature, such for example as earthy oxides or other metallic salts. It is preferred however to employ a mixture of silicates, such as an earth silicate, giving a body, and an alkaline silicate which serves as a cementing material.

What I claim as new, and desire to secure by Letters Patent, is

1. The process of making insulating material which consists in applying non-carbonaceous material to sheets of paper, piling said sheets together, and drying the resultingmass.

2. The process of making insulating material which consists in applying silicious or equivalent material to sheets of paper, piling said sheets together, and drying and baking the resulting mass so as to consolidate the same.

3. The process of making insulating material which consists in applying to paper sheets an earthy or mineral substance with a binding material, piling said sheets together and drying and heating the resulting mass.

4. As a new article of manufacture, an insulating material consisting of layers of carbonaceous material alternating with layers of silicious material.

5. As a new article of manufacture, an insulating material consisting of layers of more or less carbonized paper and intervening layers of more or less vitrified silicious material.

In witness whereof I have hereunto set my hand this 27th day of October, 1891.

ELIHU THOMSON.

Witnesses:

JOHN W. GIBBONEY, ALBERT L. ROHRER.