US690856A - Method of making glowers for electric lamps. - Google Patents

Description

No. 690,856." Patented Jan. 7, I902.

m. w. HANKS.

METHOD QF'MAKING GLUWERS FOR ELECTRIC LAMPS.

(Application filed June 7, 1900.)

(No Model.)

WITNESSES INVEH T0 if @m THE norms Pz'rgns co. wommwoqwlxsumcron. o c.

UNITED STATES PATENT OFFICE.

I/IARSHALL WILFRED HANKS, OF PITTSBURG, PENNSYLVANIA,ASSIGNOR TO GEORGE WESTINGHOUSE, OF PITTSBURG, PENNSYLVANIA.

METHOD OF MAKING GLOWERS FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 690,856, dated January '7, 1902. Application filed June 7, 1900. Serial No. 19,382- (No specimens.)

To CtZZ whom it may concern:

Be it known that I, MARSHALL WILFRED HANKs, a citizen of the United States, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Methods of Making Glowers for Electric Lamps, of which the following is a specification.

My invention relates to the manufacture of electric-lamp glowers that are non-conductive when cold and conductive when hot; and it has for its object to provide certain improved methods in the manufacture and treatment of glowers which shall facilitate such manufacture and treatment and at the same time insure the production of glowers that are more nearly perfect in composition and form than those heretofore generally produced.

With these ends in view I have devised the improvements which will be hereinafter described.

Certain means for practicing my invention are illustratedin the accompanying drawings, in which-= Figure 1 is a diagrammatic view of a threephase arc-furnace for treating glowers. Fig. 2 is a diagrammatic view of a two-carbon arcfurnace; and Fig. 3 is a view similar to Fig. 2, but illustrating the furnace operated from a constant-current circuit.

It has been my usual practice in the manufacture of glowers to utilize the are formed between two carbon electrodes in order to form a bead on each end of the glower, in which is embedded one end of a platinum terminal wire, and since an alternating current is usually employed for this purpose it has usually been found necessary to manipulate the glowcr by hand in order to keep the melted bead exactly on the end of the blank, the are being so unsteady as to have a tendency to move around to either one side or the other of the melted bead, and thus correspondingly move the bead to one side or the other. I have found that by employing threephase currents and three carbon electrodes a steady arc may be secured, so that the glowers may be fed into the arc automatically I have also These impurities have been found very injurious, and I have therefore devised means for preventing such deposits. It has been usual prior to my present invention to prevent the condensation of the fumes on the glower by blowing ajet of air on the are from above the same; but this was found undesirable, for the reason that it disturbed the arc, so as to prevent the securing, of satisfactory results in the formation of beads. In order to overcome the difficulties above stated, I

place the open end of a tube beneath the arc and connect the other end of the tube with a suitable apparatus for producing suction therein, and thus draw down all fumes or other foreign matter introduced into the are from the electrodes,and thus prevent deposits upon the glower. I find in practice that the use of this suction not only removes all impurities from the are, but does it without disturbing or interfering with its operation in connection with the glower.

Referring now more particularly to the drawings, in Fig. 1 the carbon electrodes or pencils 1, 2, and 3 are supplied with threephase currents from a source 4, which may be either a three-phase dynamo or the secondary of a transformer. Inasmuch as it is desirable to maintain a constant current in the arc-furnace, I include in each conductor between each pencil or electrode and the source of the current a steadying resistance 5, switches 6 being also shown for disconnecting thefurnace from the source of current. The resistance 5 may be adjustable, if desired, in order to vary the temperature of the are produced between the electrodes 1, 2, and 3. The means for producing suction to remove the fumes is indicated as a pipe 7, the open end of which is located adjacent to and beneath the ends of the electrodes between which the arcs are formed. A blank 8, from which a glower is formed, is shown as supported by means of a pair of tweezers 9, so that its lower end is located in the are for the purpose of forming a terminal bead thereon.

In Fig. 2 I have shown the two carbon electrodes 10 and 11 as supplied with energy from a constant-potential circuit 12, the stead-ying resistances 13 being employed for the purpose of maintaining a substantially constant current. The apparatus here shown is also employed for the purpose of forming a head on the end of the blank, the suction device 7 being used for the same purpose as in the apparatus shown in Fig. 1. In Fig. 3 the arrangement is the same as that shown in Fig. 2, except that the circuit 14 for supplying the current to the electrodes 10 and 11 is a constant-current circuit, and consequently the steadying resistances 13 are not employed. In this figure a resistance 15is shown as connected in shunt to the arc.

In each of the forms of apparatus illustrated it is of course possible to vary the amount of resistance in circuit, and though no specific means has been shown for this purpose the feasibility of adjusting or varying the amount of resistance in a circuit is so well known in the art that illustration thereof has been deemed unnecessary.

I do not desire to limit my invention to any specific apparatus or to all the steps hereinbefore described. My invention is therefore .not to be considered as restricted, exceptin so far as limitations may be definitely expressed in the claims.

I claim as my invention 1. The improvement in the art of treating glowers which consists in subjecting a glowerblank to an electric are formed between a plurality of carbon electrodes and at the same time withdrawing the products of combustion.-

electrodes and at the same time withdraw-' ing the products of combustion by suction.

3. The improvement in the art of making glowers which consists in subjecting the glower-blank or some part of it to an are formed between three electrodes supplied with current from a three-phase circuit.

4. The improvement in the art .of making glowers which consists in forming a terminal head on the end of the glower in an electric are formed between three carbon electrodes traversed by three-phase currents.

5. The improvement in the art of making glowers which consists in forming a terminal bead on the end of a glower in an electric are formed between three carbon electrodes traversed by three-phase currents and at the same time withdrawing the products of combustion by suction- In testimony whereof I have hereunto subscribed my name this 4th day of June, 1900.

I MARSHALL WILFRED HANKS.

Witnesses:

MURRAY CHARLES BEEBE, EDWARD BENNETT.

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