US652504A - Electric heater. - Google Patents

Description

E. B E N N ETT.E

ELECTRIC HBA-IER.

(Application led Tf", 1899J;

l'llllll /NVE/VTOH aml M TTOHNEY.

v W/TNESSES VUNITED STATES PrrruNTy QFBICE. 'I

wEsmNeHousE, or PITTSBURG, PENNSYLVANIA# Application tied December 7, 1899. seriarmsam. (Nqmtaeief:

^ L.To all whom it may concern:

Beit known that I, EDWARDKBENNETT, a

a citizen of the United States, residing at Jeannette, in the county of Westmoreland and State of Pennsylvania, have invented a new and useful Improvement in Electric Heaters,

(Case No. 852,) of which the following is a specification.

My invention relates to electric heaters, and has particular reference to devices employed in connection with electric lamps of the class in which the glowers are non-conductors of electricity when cold, but become luminousconductors when heated to the proper temperature.

The object of my inventionv is to provide a heater for use in raising the lamp-glowers to a proper temperature which shall be simple and inexpensive in construction and effective in operation and one which shall be less liable to injury in process of construction and in use than the devices heretofore employed for performing the same function.

It has been proposed prior to 'my invention to wind the heater-wire in a helical coil on the surface of a tube of insulating refractory material and to fasten the ends of such wire to terminal wires of larger size. The means heretofore employed for fastening the terminal wires to the tube comprised notches cut in the tube near. its ends, the terminal wires being-wound about the tube in such notches and their free ends twisted together` It was found in practice that the notches'cut in the tube weakened it very materially and the twisting of the terminal wires together was liable to result in breaking either them or the tube or both. The bending and twisting of the terminal wires also frequently loosened the heater-wire from the surface of the tube and left it exposed, so that it was fused by the first rush of current when the heater was put into use.

In order to avoid the difficulties and objections specifled above,l have devised the heater shown in the accompanying drawings, in whichl Figure l is a side elevation of one forni of heater-tube, showing the terminal wires in position and the heater-wire before the outer ELECTRIC HEATER.

SPECIFICATION forming par@ of Letters Patent No. 652,504, dateat'unei 12e',-'lato coating is applied. 1?`ig.f2,is,any endgeleyation of the heater shown inligfl'. 'Figsgfaand 4 are respectively a side and. attendueleyation of the form of heater shotynngFigsflfand 2 with the heater-wire covered andcuibodying4 a slightly-modified arrangemen-t'of ,terminal wires. Figs. 5 and are' resptivelyaplan view and an end elevation of a heate'ryhaving the modified form oftube`-f` Referring particularlytoFigsl to t elusive, the tube l is moldedlfrq .talcum or other suitable insulating'refractory material and subsequently baked. iBefore being baked, however, holes"slightlylarger than the terminal wire to be employedlare' punched through the tube near each end." i The tihli nal wires 2 are .threaded'througlr the'holes, and a small quantity of sui-table'paste -isfthen .applied to each hole around 'the' wire.- The tube is then baked until it becomes sufficiently hard for the purpose for which it is to be elnployed. In the baking operation the paste applied to the apertures becomes fused` and seals the terminal wires securely in position. The heater-Wire 3 is then wound about the tube l as a helical coil and its ends attached to the ends of the terminal Wires 2, project* ing from one side of the tube.

In case the heater is to be high-voltage circuit and the heater-wire is consequently small in cross-section the ends of the wire may be attached to thev terminal wires by wrapping them around the ends of the latter, as indicated in Figs. 2 and 4, and at the right hand in Figs. l and 3, after which theprojecting'ends of the terminal wires may be bent over against the surface of the tube, as' indicated at the left in Figs. 1 and 3. In case the heater is to be employed in low-'voltage circuits carrying relatively-large currents the heater-wire is fused to the lead-wire at the start, and at the completion of the winding it is twisted around the other leadwire and fused to it and then bent down to the surface of the tube. is rendered necessary in order to avoid the destruction of the heater-wire by' reason of the poor contact which would be made by merely twisting the same around the terminal Wire.

employed in a.

Thisl construction In case the tube is to be applied to a spindle or mandrel for the purpose of winding the the port-ion of the termi- A tion of the terminal and heater wires is also made in the same manner as that already described.

Whatever may be the form of the heater it will preferably be provided with a coating 4 of -non conducting refractory material of sufficient thickness to cover and embed the heater-wire.

I desire it to be understood that the composition, size, and arrangement of the several parts of the heater may be varied from "what is shown without departing from my invention and that the heater is not necessarily restricted to use in connection withwelectric lamps. r,

I' claim as my invention- 1. An electric heater comprising a tube of insulating,refractory material,terminal wires y projecting through perforations adjacent to the ends of the tube and fused therein, and a heater-wire helically coiled around the tube and having its ends joined to the terminal Wires, `Substantially as described.

2. An electric heater comprising a tube of insulating, refractory material having apertures adjacent to its ends, terminal wires projecting through said apertures and fused therein, and a heater-wire helically coiled around the tube and having each end joined to a projecting end of a terminal Wire, substantially as described.

3. An electric heater for electric lamps of the. type described comprising a attened tube of insulating, refractory material' provided with terminal wires projecting through and fused into openings in said tube and having a coiled heater-Wire joined to the terminal wires, substantially as desc-ribed.

4. An electric heater comprising a tube of insulating, refractory material of approximately-elliptical cross-section and having ap ertures adjacent to its ends, terminal wires projecting through and fused into said apertures, and a heater-wire coiled around the tube and joined at. its ends. to the terminal wire, substantially as described.

In testimony whereof l have hereunto subscribed my name this 5th day of December, 1899.

ED\VARD BENNETT.

iVitnc-sscs:

H. A. (JRooKs, WESLEY G. CARR.

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