US 252386 A
Description (OCR text may contain errors)
(NVOMOdeL) L. H. LATIMER.
PROCESS 0F MANUFACTURING CARBONS.
Patented Jan. 17,1882.
'f iV// Fig.' 3
UNITED STATES PATENT. OFFICE.
LEWIS H. LATIMER, OF NEW YORK, N. Y., ASSIGNOR TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF SAME PLACE.
PROCESS'OF MANUFACTURING CARBONS.
SPECIFICATION forming' part of Letters Patent No. 252,386, dated January 17, 1882.',
Application tiled February 19, 1881. (No model.)
To all whom it may concern:
Be it known that I, LEWIS H. LATIMER, of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in the Manufacture of Carbons for Electric Lamps, of which the following is a specification, reference being had to the drawings accompanying and forming a part thereof.
1o My invention relates more particularly to carbonizing the conductors for incandescent lamps, though it is equally applicable to the manufacture of delicate sheets or strips of dense and tough carbon designed for any purpose whatever; and it consists in carbonizing blanks and forms of textile, fibrous, or other carbonizable material in protecting-envelopes of a material whose rate of contraction, when exposed to a high temperature and under conzo ditions which preclude the admission of air, is
the same, or approximately the same, as their own.
In the methods ofcarbonizing employed previous to my invent-ion the blanks cut from fibrous or textile materials were confined in grooves or laid between plates of metal or carbon and charred inasutableclosed inutile. To prevent the strips from adhering to the plates they were coated with graphite or laid between 3o strips of thin tissue-paper. W hen heated the confining-plates expand, while the blinks between them contract very considerably under the intense heat of the furnace, so that many ofthem are broken and distortedin consequence of their extremely-delicate structure and their tendency to shift their position between the plates. This I avoid by the method I propose, and which is illustrated in the accompanying drawings, in which- Figure 1 illustrates the method of inclosing the blanks in the protective envelopes; Fig. 2, sectional view of the earbonizer, and Fig 3 a plan -view of a portion of the cover for use therewith.
The blanks a, of fibrous material, usually such as paper, strips of wood, or the like, are inclosed in small envelopes composed of sheets ot' card-board b c, which are sufiiciently strong to prevent cracking or crumbling when carbon- 5o ized.
The blanks are prevented from sticking to the envelopes by coating them or the inner faces ot' the envelopes with graphite, lampblack, or similar non-adhesive substance,or by interposing between the two strips of tiss'ue- 55 paper.
A is a retort or mue for carbonizing the blanks. It is composed of a box of refractory material with handle B and a corrugated bottom, C, upon which is placed a block or plate, 6o F, of fire-clay, metal, or other refractory material. Upon this plate F are spread a. number of the envelopesH, inclosing the blanks to be carbonized. Over these another plate, ofsimilar character, is laid, then other enveloped blanks and plates until the box is' nearly full. The whole is covered by a perforated plate, D, on which is placed a layer of sand, some raw cotton being spread over the perforations E in the cover to prevent the sand from filtering 7o through into the carbonizer. This also prevents the access of air into the box, while allowing the gas driven off by the heat to escape. The plat-es F are somewhat smaller than the interior ofthe boxfA, so that the gases which are driven 'off by the heat, or which may be introduced in the process of carbonization, have free passage for their escape, as shown by the arrows in Fig.2. The weightof the superposed cover and sand exerts a continuouspressure on 8o the layers ot' blanks between the plates, thus lessening their tendency to buckle or warp, and confining their only injurious movement to a horizontal contraction. By the use ofthe paper sheets or envelopes inclosing the delicate blanks, the latter are protected from attrition with the plates when the latter are expanded by the heat.
The sheets b c must be of reasonably stout cardboard, or of a substance of such tenacity 9c of liber that it will not easily crack or break when carbonized.
I would also state that instead of an envelope for each blank several blanks may be inclosed in each envelope; but the arrangement shown is the one preferred by me, as in practice I have found it the most practicable and productive of the best results.
I am aware that blanks of the kind described have been carbonized in a closed muide or tlask roo and between plates of iron, carbon, or other refractory material. I am also aware that for preventing the blanks from adhering to the said plates, strips ot' tissue-paper have been laid between them, and this I have described in conjtuiction'nith my present invention, but do not desire to lay claim herein to the same, broadly; but, v
Having now described my invention, what I claim is- 1. The process of earbonizing shapes or blanks of carbonizable material, substantially as described, which consists in subjecting the same to a high temperature while inclosed in envelopes or between sheets of card-board or equivalent material whose rate of expansion L. H. LATIMER.
EDWARD P. ROBERTS, JOSEPH V. NICHOLS.